Lake Shore Cryotronics CRX-6.5K User Manual Download Page 110

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100

CHAPTER 4:

Basic Operation

Model CRX-6.5K Probe Station

Probe station cool down

to base temperature

Maintaining sample

stage at base temp

Operating sample

stage 10 K t0 350 K

Returning probe station

to room temperature

CCR control
settings

Main power

On/Off

Off

Electronic
control
settings

Sample stage

Heater range

Off

See TABLE 4-5

High (100 W)

Nominal power

—

See TABLE 4-5

100%

Radiation shield stage

Heater range

Off

On (50 W)

Nominal power

—

100%

TABLE 4-4

General CCR and electronic control settings

Sample stage

Base to 20 K

20 K to 100 K

100 K to 250 K

250 K to 350 K

Nominal power

10% at 10 K

13% at 50 K

21% at 200 K

33% at 350 K

Heater range

Med

High

Proportional (P)

100

Integral (I)

Derivative (D)

Heater power values are based on a 4-arm configuration with probe mounts tied to the sample stage.

TABLE 4-5

Base temperature and up electronic control settings for the sample stage

Summary of Contents for CRX-6.5K

Page 1: ... support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice ...

Page 2: ...Lake Shore undertakes no responsibility that the products will be fit for any particular purpose for which you may be buying the Products Any implied warranty is limited in duration to the warranty period No oral or written information or advice given by the Company its Agents or Employees shall create a warranty or in any way increase the scope of this limited warranty Some countries states or pr...

Page 3: ...re those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or symbol Apiezon is a registered trademark of M I Materials Ltd Parker s Perfect is a is a registered trademark of Edmund Optics Kimwipes is a registered trademark of Kimberly Clark Worldwide Stycast is a registered trademark of Emerson Cuming Tarn X is a regi...

Page 4: ...Model CRX 6 5K Probe Station ...

Page 5: ...icrowave Compatible Probes 18 2 3 3 2 Microwave Compatible Cables and Connectors 19 2 3 3 3 Microwave Calibration Substrate 19 2 3 4 Optical Fiber Assembly 20 2 3 5 Sample Holders 20 2 3 5 1 Grounded Sample Holders 20 2 3 5 2 Isolated Sample Holders 20 2 3 5 3 Coaxial Sample Holders 21 2 3 5 4 Triaxial Sample Holders 21 2 3 6 Vision System Configuration 21 2 3 6 1 Microscopes 21 2 3 6 2 Lighting T...

Page 6: ... 2 6 7 Lab Protocol 41 Chapter 3 Installation and Setup 3 1 General 43 3 1 1 Lake Shore Assisted Installation 43 3 2 Site Requirements 43 3 2 1 Space Requirements and Suggested Layout 44 3 2 2 Environmental Requirements and Concerns 45 3 2 2 1 Vibration 45 3 2 2 2 Electrical Noise 45 3 2 2 3 Ventilation 45 3 2 2 4 Safety Compliance 45 3 2 3 Power Requirements 46 3 2 4 Water Requirements 47 3 2 4 1...

Page 7: ...ing a ZN50 Probe 70 3 7 2 1 Installing the ZN50 Probe Mount 71 3 7 2 2 Installing the ZN50 Probe Blade 72 3 7 3 Removing a ZN50 Probe 73 3 7 3 1 Removing the ZN50 Probe Blade 73 3 7 3 2 Removing the ZN50 Probe Mount 75 3 7 4 Installing a Microwave Probe 75 3 7 5 Removing a Microwave Probe 77 3 8 System Verification and Testing 78 3 8 1 Instrumentation Verification 78 3 8 1 1 Verifying Voltages 78 ...

Page 8: ...educing Condensation on the Sample 105 5 2 1 1 Heated Cycle Purge 105 5 2 1 2 Maintaining the Sample at Room Temperature While Cooling the Probe Station 106 5 2 2 High Temperature Sample Stage Operation 106 5 2 2 1 Configuring the Model CRX 6 5K for High Temperature Sample Stage Operation 106 5 2 2 2 HT Sample Stage Installation 108 5 2 2 3 HT Sample Stage Removal 109 5 2 2 4 Reconfiguring the Mod...

Page 9: ... the Vacuum Chamber 134 6 3 Troubleshooting Procedures 135 6 3 1 Vacuum Troubleshooting 135 6 3 1 1 Testing the Turbo Vacuum Pump Alone 136 6 3 1 2 Testing the Vacuum Pumping System Along with the Connection to the Probe Station 136 6 3 1 3 Testing the Vacuum Pumping System the Connection to the Probe Station and the Probe Station Vacuum Chamber 137 6 3 1 4 The Impact of Cryopumping 137 6 3 1 5 Va...

Page 10: ...6 6 3 5 3 Loss of Continuity 146 6 4 Service Reference 147 6 4 1 Power Requirements 147 6 4 2 Pin Outs 148 6 4 3 Instrumentation Wiring Diagram 149 6 5 Technical Inquiries 151 6 5 1 Contacting Lake Shore 151 6 5 2 Return of Equipment 151 6 5 3 RMA Valid Period 151 6 5 4 Shipping Charges 151 6 5 5 Restocking Fee 151 ...

Page 11: ...looking for the convenience of cryogen free operation and the excep tional measurement performance of a Lake Shore product Using a self contained closed cycle refrigerator CCR the station will cool down to cryogenic temperatures unassisted eliminating the need for monitoring by the researcher Various options and configurations on the Model CRX 6 5K enable the researchertoconduct exacting challengi...

Page 12: ...anchoredaslistedinthe Probingsection below CONTROL STABILITY Sample stage temperature Stability Base temperature no heater control Not specified 10 K 25 mK 11 K to 350 K 10 mK Cooling source 50 mK VACUUM Room temperature 5 10 4 Torr Base temperature 1 10 5 Torr Maximum temperature 5 10 5 Torr CYCLE TIME LHe 6 25 h Pump down 0 5 h Station cool down 3 5 h Station warm up 2 25 h VIBRATION AT SAMPLE 2...

Page 13: ... Fiber optic probes Available for electro optical measurements Probe landing All probes can land at single point in 25 4 mm 1 in diameter circle CRYOGEN CONSUMPTION Room to base temperature total Not required Helium at 5 K Not required TABLE 1 1 Model CRX 6 5K probe station specifications ...

Page 14: ...all Chamber access 152 mm 6 in diameter opening Viewport 63 5 mm 2 5 in diameter fused quartz Viewing area 54 0 mm 2 13 in diameter Pump port NW 25 with included vacuum isolation valve Gauge port NW 25 Gas port 0 25 in NPT with valve Over pressure safety 3 5 kPa 0 5 psi pressure relief valve RADIATION SHIELDING Material Electroless nickel plated aluminum Sample access 132 mm 5 2 in diameter lid Vi...

Page 15: ...ons not to exceed 10 of the nominal voltage D Overvoltage category II D Pollution degree 2 Power and Ground Connections 1 phase to minimize shock hazard the probe station is equipped with a 3 conductor AC power cable Plug the power cable into an approved 3 contact electrical outlet or use a 3 contact adapter with the grounding wire green firmly connected to an elec trical ground safety ground at t...

Page 16: ...o Class II of IEC 536 see Annex H CAUTION High voltages danger of electric shock background color yellow symbol and outline black CAUTION or WARNING See instrument documentation background color yellow symbol and outline black Off supply On supply Frame or chassis terminal Protective conductor terminal Earth ground terminal Alternating or direct current power line Alternating current power line ...

Page 17: ...hapter 1 2 2 Major Components This section is intended as a reference for identifying assemblies operator interfaces and controls called out in later chapters A Model CRX 6 5K probe station comprises the probe station itself and five major sub systems FIGURE 2 1 illustrates an overall view of the full system Each major component is detailed in the following sections FIGURE 2 1 CRX 6 5K probe stati...

Page 18: ...of the probe station include the vacuum chamber sample cooling assembly baseplate and outer stand probe arm assemblies two stage closed cycle refrigerator CCR CCR stand and ballast weights FIGURE 2 2 illustrates the probe station components FIGURE 2 2 Probe station CCR cold head Vacuum chamber Baseplate Probe arm assembly Probe arm assembly Samplecoolingassembly CCR stand CCR second stage Cryocool...

Page 19: ...ation isolation bellows Major components of the vacuum chamber include the vacuum chamber lid chamber viewport vacuum line purge valve pressure relief valve electrical feedthroughs and auxiliary gauge port Major components of the CCR vacuum shroud are the vacuum isolation valve and the electrical feedthrough for the CCR thermometry FIGURE 2 3 illustrates the vacuum chamber and CCR vacuum shroud FI...

Page 20: ... sensor and resistive heating element on the sample stage provide a means for sample temperature control Temperature sensors and heaters on the radiation shield CCR first and CCR second stages allow temperature monitoring and quick warm up to room temperature for sample exchange FIGURE 2 4 illustrates the sample cooling assembly FIGURE 2 4 Sample cooling assembly Radiation shield viewport Radiatio...

Page 21: ...e cold head is a two stage Gifford McMahon GM cycle cryocooler The compressor unit supplies the power to the cold head via the cold head power cable and it supplies the high pressure helium gas to the cold head via the flexible helium lines The compressor unit requires cooling water and power for operation FIGURE 2 5 illustrates the CCR FIGURE 2 5 Closed cycle refrigerator Input power cable to fac...

Page 22: ...ipulated translation stages with micrometer or hand dial controls probe arm base top feedthrough for user configurable signal connector bellows probe arm arm shield braids probe arm sensor provided on one arm and optional planarization adjustment FIGURE 2 6 and FIGURE 2 7 illustrate the micro manipulated stages FIGURE 2 6 Micro manipulated stage FIGURE 2 7 Micro manipulated stage showing optional ...

Page 23: ...K probe station includes a Model 336 temperature controller FIGURE 2 8 illustrates the temperature instrumentation and provides a summary of the probe station component that is monitored or controlled by each controller input FIGURE 2 8 Model 336 temperature controller ...

Page 24: ...utput pressure regulator pressure gauges and gas output Pure dry inert gas such as argon or nitrogen is recommended to purge the vacuum chamber FIGURE 2 9 illustrates the pressurized gas system FIGURE 2 9 Pressurized gas system profile Shut off Output pressure regulator Output pressure gauge Tank pressure gauge Pressurized gas tank Gas output ...

Page 25: ...or components of the turbo pumping system typically include the controller turbo pump oil free dry scroll backing pump vacuum gauge and vent valve FIGURE 2 11 illustrates the TPS FRG turbo pumping system FIGURE 2 10 Vision system with ring light shown Hand dial Microscope Ring light Viewport Chamber Monitor Horizontal boom swing arm S video cable Color CCD camera Optical fiber cable Light source V...

Page 26: ...r for monitoring nominal arm temperature Additional sensors are available as PA SEN temperature sensor options but must be ordered with the arm and base assembly Probing configurations are divided into three basic groups DC RF section 2 3 2 microwave section 2 3 3 and optical fiber section 2 3 4 2 3 2 DC RF ZN50 Probe Configurations DC RF ZN50 probes are commonly used for electrical probing in the...

Page 27: ...the guard contact The connector s signal to guard resistance is specified at 10 G and is typically 50 G when it is clean and dry The impact of leakage current on measurement uncertainty is further reduced by proper guarding The Teflon insulated ultra miniature cryogenic coaxial cable provides operation up to 50 MHz and 500 K with low thermal conductivity The probe arm sensor should be monitored wh...

Page 28: ...by the connector used The microwave probe must be specified with the same frequency and connector type as the probe cable All microwave probes are constructed with ground signal ground GSG geometry and are designed for use with coplanar waveguides The BeCu signal and ground points are 10 µm to 12 µm planar triangular structures The pitch or spacing between the probe points can be specified from 50...

Page 29: ...uration can also be used with external measurement cables with either K connectors or SMA connectors The semirigid microwave cable is limited to operation below 350 K 2 V connector 1 85 mm with semirigid cable this is a precision microwave connection rated for continuous mode free operation from DC to 67 GHz V connectors mate to 2 4 mm connectors This configuration can be used with external measur...

Page 30: ...red to as grounded because the back side of the sample is held at system ground They are recommended for routine measurements especially when samples are patterned on highly insulating substrates or leakage current is not a concern They are constructed out of solid metal making them the most thermally and electrically conductive The smallest thermal gradient between the sample stage and sample mou...

Page 31: ... to medium thermal gradients between the sample stage and sample mounting surface should be expected The maximum operating temperature is 350 K 2 3 6 Vision System Configuration The probe station s vision system is critical for distinguishing characteristics of the sample and properly landing probes The vision system can be optimized for the type of sample that is most frequently probed There are ...

Page 32: ...the sample This allows the vision system to image very highly reflective samples such as those patterned on polished silicon FIGURE 2 18 left is an image of four gold circles 10 µm to 100 µm in diameter patterned on a highly reflective surface illuminated with a coaxial light Although the image appears relatively flat and has modest contrast it is more than adequate for properly landing probes FIG...

Page 33: ...TP KIT option contains the necessary connections and adapters for connecting the Model TPS FRG to the probe station Pumping systems can also be sourced locally Turbo pumps with similar base pressure and pumping speed to those listed in TABLE 2 2 are recommended A vacuum line and fittings to adapt the pump system to the Model CRX 6 5K probe station s NW 40 vacuum isolation valve must also be provid...

Page 34: ...on Prior to June of 2013 the Model CRX 6 5K refrigerator needed to be configured at the factory with the electrical wiring for operating the HT sample stage After that date the Model CRX 6 5K refrigerator is pre wired for upgrade to the high temperature stage 2 3 9 Pump Line Vibration Isolator PS PLVI 40 Vacuum pumps are a common source of vibration that can impact sensitive measurements A pump li...

Page 35: ...cuum chamber is typically tied to earth ground to form a shield around the sample and probes The Model CRX 6 5K is configured this way if it is assembled according to the instructions in Chapter 3 The shield conductor of the temperature controller cable is used to give the chamber a low impedance path to earth ground FIGURE 2 20 Grounding the vacuum chamber through the Model 336 is not appropriate...

Page 36: ...ing the effect of ground loops can be difficult some experimentation may be required to achieve the best results One of the biggest difficulties is that signal sources and acquisition electronics often operate with one lead internally referenced to earth ground so the overall grounding system must take this into account The best approach is to make the system a poor receiver for the noise Never re...

Page 37: ... wire so the shielding can be carried inside the chamber and down the probe arm Outside the chamber shielding is recommended for all signal cables but the shielding must not be allowed to create ground loops as described in section 2 4 1 2 It is often necessary to connect the shield at only one end of the cable 2 4 1 4 Noise Isolation Every attempt was made in the design and construction of the Mo...

Page 38: ...t electrical and thermal contact to the sample stage This is the most basic measurement configuration and it suits the needs of many DC research applications FIGURE 2 21 FIGURE 2 21 Basic configuration for DC measurements Radiation shield stage ZN50 probe Sample stage Cryogenic coaxial cable Coaxial BNC signal connector Probe arm base Probe arm shield To temperature controller chassis 19 pin conne...

Page 39: ... can add additional information it shows the forward transmission response of a pair of ZN50 probes configured with K connectors and semirigid cable While the probes do have a response out to 1 GHz the separation of the ground path from the single signal tip of the ZN50 blade causes a large dip in transmission forward gain at 0 3 GHz 300 MHz Depending on the configuration of the probes and measure...

Page 40: ...easurements The noise isolation features described in section 2 4 1 4 may be insufficient when making low noise measurements Please consider the following when setting up a low noise experiment Never remove earth safety ground protection from electronic equipment 1 Make every effort to isolate other noisy components pumps compressors switching power supplies when they are added to the system 2 Ele...

Page 41: ...ture longer before taking data It often takes several minutes after the sample stage temperature sensor stabilizes before the sample comes to equilibrium Cryogenic experiments are most often designed to cool the system to base temperature first Temperature is then increased between data points to provide the best sample temperature stability 3 Vibration isolation the vibration present in a typical...

Page 42: ...ally flows between conductors in the leads used to connect the sample to measurement electronics The most common leakage path is between the signal leads and their respective shield or ground Properly configured a guarded measurement system can reduce leakage current by three orders of magnitude or more which would allow a system capable of accurately measuring 10 M to 100 M to measure 10 G to 100...

Page 43: ...le must be guarded in addition to the cables There is a potential leakage path through the sample substrate to a standard grounded sample holder The SH 1 25 C or SH 2 00 C coaxial sample holder is recommended for guarding samples in the Model CRX 6 5K The FT BNC coaxial feedthrough is used to bring the guard voltage into the chamber and to the sample holder When the experiment requires guarding an...

Page 44: ...ally designed to ensure operator safety when these voltages are present Because Lake Shore has no way to predict how the hazardous live voltages would be configured or operated it is impossible for us to guarantee safety in the event of improper operation accidentalmisconnectionor componentfailure The ModelCRX 6 5K does not include the safety interlocks current limits or earth safety ground system...

Page 45: ...urements in the probe station Properly installed the cables provide a low loss broad band electrical path with minimal crosstalk Also they need to be compatible with the cryogenic temperatures and vacuum for the Model CRX 6 5K The geometry of the Model CRX 6 5K requires that the cables extend 229 mm 9 in into the vacuum chamber with a single 90 degree bend The total length of the microwave cable i...

Page 46: ...two outer points of the GSG probe tip The outer conductor is also electrically connected to the microwave probe body so the measurement reference ground is electrically connected to the sample cooling assembly through the probe mount braids Keep in mind that this electrical connection may be broken if desired by removing the anchors from the sample stage however please note that this will also rem...

Page 47: ...crosstalk between adjacent probes Probe tips that are properly landed on measurement pads that have 50 impedance radiate very little signal Poorly landed or open probe tips radiate significantly more Therefore properly land or move away any active probes that are not involved with the measurement or calibration Probes that are oriented across from each other in line have higher crosstalk coupling ...

Page 48: ...ion substrate The measurements were made using a commercial VNA calibration using mechanical standards that places the measurement reference plane at the end of the VNA measurement cables that are connected to the input connectors of the 67 GHz probe arms FIGURE 2 33 shows the frequency dependent characteristics of the probe station with the 67 GHz probes and probe arms The performance looks very ...

Page 49: ... 300 K temperature Note the error in the calibration as compared to FIGURE 2 34 The error is due in part to the temperature changes in the arms and probes as well as the coplanar waveguide physically changing geometry which causes errors in the VNA calibration correction coefficients The calibration error is on the order of 1 to 2 dB for this particular calibration that spans 40 MHz to 67 GHz and ...

Page 50: ...1 2 6 2 Contact Area In addition to contact material contact area is a major factor in the ultimate contact resistance Lake Shore offers probe tips with a variety of radii In general a larger tip radius will create a larger contact area but this may not translate to lower contact resistance as several factors dictate how much surface is actually in contact Focusing on the metal to metal interface ...

Page 51: ...ed when oxides or other contamination is present between the conductive surfaces They exhibit a non linear relationship between current and voltage more closely resembling a diode This is undesirable because signals resulting from the contact cannot easily be subtracted from the desired signal of the sample 2 6 6 Measuring Contact Quality Measuring contact quality is always recommended for critica...

Page 52: ...42 CHAPTER 2 System Overview Model CRX 6 5K Probe Station ...

Page 53: ...ns engineer contact information shortly after the order is placed To avoid delays in the installation process please read the form carefully as soon as it arrives Customers are responsible for completing section 3 2 through section 3 5 before an installation trip can be scheduled 3 2 Site Requirements This section describes the space utilities and equipment that must be provided at the installatio...

Page 54: ...ing a risk to the operator A suggested floor plan is illustrated in FIGURE 3 1 The suggested layout can be mirrored or rearranged to fit in the available space FIGURE 3 2 illustrates the necessary ceiling height for the probe station and associated components FIGURE 3 1 Suggested floor plan FIGURE 3 2 Suggested elevation CCR compressor Vacuum pump Probe station Light source Monitor Model 336 Heliu...

Page 55: ...void interference withprobemeasurements Commonelectricalnoise sourcesinbuildings are power distribution panels high capacity power lines communications distribution centers and RF radio transmitters Line power quality can also impact electrical measurements performed in the probe station When possible avoid long or indirect power routing circuits that are shared with motors or other noisy loads un...

Page 56: ...cal safety codes to the CCR compressor The turbo pumping station should be powered from a separate circuit to isolate electrical noise from the sensitive electronic instruments The circuit protection used for the turbo pumping system should be capable of handling high inrush currents The CCR compressor will draw high inrush currents when powered on Circuit protection capable of handling these shor...

Page 57: ...TABLE 3 4 for specific parameters for the CCR compressor Do not use demineralized water because it may cause a leakage or malfunction When cooling with tap water chemistry is less of an issue because fresh water is constantly running through the system diluting any contamination Use a well maintained water filter to remove any sediment that could cause a clog Recirculating water systems have many ...

Page 58: ...e the ability to attain at least 10 3 Torr in the probe station while at room temperature A vacuum isolation valve with an NW 25 flange is included on the CCR vacuum shroud Lake Shore offers the TPS FRG for evacuating the chamber Components and specifications for these options are in section 2 3 7 You should use these specifications as a guideline if you purchase the pumping system separately If y...

Page 59: ...signs of rough handling such as damage to the shipping container or broken shock indicators attached to the outside and inside of the shipping container If any physical damage is suspected do not open containers before photographing the damage and informing the shipping agents and Lake Shore or your local representative Contact information for Lake Shore service is given in section 6 5 Shipping co...

Page 60: ...r CCR stand must be locked together with the locking bolts and red spacing washers shown in Failure to secure these together before lifting will result in permanent damage to the probe station 3 3 5 Uncrating the Probe Station These steps will assist you in safely removing the probe station from its crate 1 Using a Phillips head screw driver remove the screws from the top of the crate containing t...

Page 61: ...manipulation stages 6 Using lifting equipment lift the probe station off the crate base FIGURE 3 3 7 Move the crate materials out of the work area It is advisable to save these in the event that you need to return the probe station 8 Move the probe station to its final location When you set it on the floor the weight of the entire station will be on the long red cross braces secured to the outer p...

Page 62: ...and FIGURE 3 6 Do not lower the probe station stand feet so that thebottom of the probestation stand is more than 85 mm above the floor Doing so will disengage the feet from the stand causing the station to tip and possible injury or death c Using a q in or adjustable wrench remove the bolts that secure the long red cross braces from the probe station FIGURE 3 7 d Move the long red cross braces ou...

Page 63: ...ides the temperature monitoring and control for the Model CRX 6 5K To unpack the controller remove the packaging and prepare the cables for routing Refer to the Model 336 user s manual if you need further information 3 3 7 2 Unpacking the Vision System The vision system is packed in its own box within the crate The microscope components are packed in bubble wrap and boxes The display is packed in ...

Page 64: ... base 3 Remove the braces securing the compressor to the wooden base 4 Lower the ramps 5 Confirm that the wheels are secure 6 Roll the compressor off of the wooden base 7 Move the crate materials out of the working area Save these in the event you need to return the CCR compressor 8 Place the compressor in its final location relative to the probe station 9 The compressor is shipped with a shipping...

Page 65: ...ting the system setup and assembly Remove the turbo pumping station from its box The turbo vacuum pump can be placed on the floor near the probe station or placed on a cart D PS TP KIT the turbo pumping kit consists of a 1 meter long NW40 flexible stainless steel vacuum line in a plastic bag A separate plastic bag contains the fittings nec essary to connect the turbo pumping system to the probe st...

Page 66: ...ining Consult the Installation section of the HC 4E1 Helium Compressor Technical Manual for instructions on connecting the power to the compressor Refer to the section above for power requirements information 3 4 2 Cooling Water Connections The water requirements for the CCR compressor are described in section 3 2 4 1 Locate the 1 2 in Swagelok compression internal connection on the compressor mar...

Page 67: ...chased from Lake Shore or separately Follow this procedure to verify proper operation of the turbo vacuum pump and gauge 1 Complete steps 1 through 2 of section 3 6 5 2 to install the gauge on the turbo vacuum pump 2 Complete section 6 3 1 1 to test the turbo vacuum pumping system 3 If a Lake Shore installation and training was purchased record the pressure achieved on the site preparation form Th...

Page 68: ...wrench provided in the Model CRX 6 5K tool kit Use it to lower the CCR stand feet until they just touch the red pads Do not add tension to the feet at this step 3 Using a q in or adjustable wrench remove the four bolts that lock the CCR stand to the probe station stand 4 Using the in wrench continue to lower the CCR stand feet until the weight of the CCR stand is removed from the four red spacing ...

Page 69: ...bottom of the CCR stand 3 6 2 Connecting the CCR Compressor to the Probe Station The flexible helium lines and electrical cable must be connected to the coldhead located in the probe station and to the CCR compressor unit Read the warnings and cautions below prior to following the steps to make these connections The CCR cold head compressor and flexible helium lines contain high pressure 1 86 MPA ...

Page 70: ...ot compromised allowing the helium gas to escape a Using your fingers start the threading of the self sealing nut b Using the two wrenches provided in the CCR tool set tighten the self sealing nut Hold the nut with one wrench and turn with the other as shown in FIGURE 3 12 Do not over tighten the maximum allowable torque is 50 Nm 4 Connect the return line to the compressor unit 5 Connect the suppl...

Page 71: ...re off FIGURE 3 14 2 Connect the cable to the cold head Note the orientation of the guiding keys and rotate as necessary to align the plug to the receptacle Thread securely FIGURE 3 15 3 Connect the cable to the compressor Note the orientation of the guiding keys and rotate as necessary to align the plug to the receptacle Thread securely FIGURE 3 15 CCR operation will be verified in section 3 8 Pr...

Page 72: ...uum chamber which has a corresponding 19 pin connection FIGURE 3 16 Note the orientation of the guiding lugs and rotate as necessary The outer shell will rotate and click into place for a secure connection 3 Locate the temperature control and sensing cable labeled DC0922 CCR that is connected to the Model 336 temperature controller 4 Attach the CCR 19 pin connector to the side of the CCR vacuum sh...

Page 73: ...either one or two shafts The Zoom 70 has one shaft and the Zoom 160 has two 1 Install the microscope vertical post as shown in FIGURE 3 18 To install the post remove the one or two M5 screws in the bottom of the post 2 Align the post so that one of the two screw holes on the vertical post mount is over the hole that is closest to the vacuum chamber The other screw hole will align with the third ho...

Page 74: ...nd dial 3 Slide the horizontal boom onto the vertical post as shown in FIGURE 3 19 You may need to turn the quick release handle counterclockwise to allow it to slide easily If the microscope physically touches the vacuum chamber lid adjust the shaft collar before moving on section 6 3 4 5 describes how to adjust the shaft collar FIGURE 3 18 Left Installing the microscope vertical post Middle Four...

Page 75: ...power supply to the monitor This is a 12 V DC connection 3 Connect the optical fiber cable The steps vary depending on whether you are using the ring light or the coaxial light Ring Light a Screw the light source adapter onto the bottom of the microscope using the three screws supplied FIGURE 3 21 Finger tighten only b Insert the fiber optic cable into the light source Finger tighten only FIGURE 3...

Page 76: ...re the set screw e Insert the fiber optic cable into the light source Finger tighten only f Connect the power cord to the light source refer to TABLE 3 1 for power requirements FIGURE 3 21 Left Installing the ring light onto the adapter Middle Tighten the ring light thumbscrews Right Fiber optic cable attached to the light source FIGURE 3 22 Left Loosen the set screw on the fiber optic cable fitti...

Page 77: ...out one minute the pressure relief valve on the chamber will open and release gas 4 Close the purge valve completely 5 The gas line can be left in place or removed 3 6 5 2 Preparing the Turbo Vacuum Pump If you purchased the turbo pump specified by Lake Shore follow this procedure to prepare it Locate the turbo pumping kit in the accessories box It contains the necessary fittings to connect the tu...

Page 78: ...IGURE 3 25 c Holding an NW 40 centering ring in place set the vacuum line against the centering ring FIGURE 3 25 d Close the clamp around the fitting e Finger tighten the clamp with the screw FIGURE 3 25 4 Remove the blank off plate from the NW 40 vacuum isolation valve on the probe station The clamp and centering ring are used when the vacuum hose is attached in the next step FIGURE 3 24 Vacuum g...

Page 79: ...obe Station Options Some options require some assembly while others come fully assembled This section explains how to assemble the options and attach them to the probe station The PS HTSTAGE high temperature stage option is explained in section 5 2 2 3 6 6 1 Assembling the Pump Line Vibration Isolator PS PLVI 40 The PS PLVI 40 is for the PS V81DPC turbo pumping system The pump line vibration isola...

Page 80: ...robe type 1 Open the vacuum chamber and radiation shield using the guidelines in section 4 3 1 2 If you purchased semirigid cables or coaxial cables there will be safety ties on the arms Cut these off and remove the ties from all cables Be careful not to cut the Kapton tape on the coaxial cables You may need to use the x axis hand dial to move the probe arms in or out so that the ties are more acc...

Page 81: ...unt in place 5 Attach the braid block The braid block is used as a thermal connection between the probe tip and the anchor location Use this procedure to attach the braid block to the sample stage before installing the probe tip to minimize the chance of accidentally hitting the probe tip a Using the x axis hand dial and y axis micrometer move the probe arm to expose the braid block mounting holes...

Page 82: ...t FIGURE 3 32 Its bottom edge should be square and flush with the bottom of the probe mount Hold the new blade in position Positioning the blade so its bottom is flush with the bottom of the probe mount ensures that the SMA connector will not contact the probe mount During operation the body of the SMA connector may have a different voltage potential on it than the probe mount and therefore it sho...

Page 83: ...pe prevents contact with the radiation shield curtains the flexible aluminized strips covering the openings or other conductive elements in the sample area which would short the guard signal to ground 3 7 3 Removing a ZN50 Probe The ZN50 series probes consist of a probe mount ceramic blade with SMA electrical connector and probe tip You can simply remove the alumina probe blade on ZN50 probes if i...

Page 84: ...e 1 5 mm hex driver loosen the visible probe mount set screw FIGURE 3 35 5 Rotate the probe mount to access the set screw on the other side of the probe mount and loosen that screw as well 6 Gently work the blade up and down to release and remove it Avoid sideways force to minimize the chance of cracking the alumina 7 Remove the blade from the system and place it back into its storage case making ...

Page 85: ...separate probe mount the microwave probe has an integrated mount that attaches to the probe arm and includes probe mount braids and a braid block for attachment to the thermal anchor point GSG microwave probe tips are extremely delicate the slightest touch on the probe tips can disturb the ground signal ground GSG transmission line geometry thereby degrading performance Due to the high cost of rep...

Page 86: ... onto the probe connector socket The probe can be rotated slightly to better align it as you thread Refer to section 5 3 6 3 if the cable length seems inappropriate 8 If the connector is properly aligned it will make good contact simply by finger tightening It is acceptable if the back of the copper probe body is not flush with the copper end of the probe arm A wrench should not be usedto tighten ...

Page 87: ... Follow this procedure to remove a microwave probe from the probe arm 1 Detach the braid block using these steps a Use the x y and z axis micrometer controls to position the probe so that the braid block can be removed without disturbing the probe tips b Using the 2 5 mm hex driver loosen the two captive screws on the braid block until it is free Detach the thermal braid block very carefully so as...

Page 88: ...t You can find more information on the controller in its manual 3 8 2 Temperature Sensor and Heater Test Each of the four stages in the Model CRX 6 5K sample stage radiation shield stage and cryocooler first and second stages has a temperature sensor and heater Prior to heating or cooling the system it is important to verify that the sensor heater cabling and temperature controller are all configu...

Page 89: ...ction 4 5 1 Do not allow the temperature on any stage to cool more than 10 K below room temperature when the system is not under vacuum Doing so will cause condensation inside the vacuum chamber which will increase the pump down time to reach the vacuum pressure required to initiate a cool down 5 Follow the procedure in section 4 5 2 2 to start the CCR and run it for 30 s The CCR second stage and ...

Page 90: ...h Follow this procedure to check the probe arm reach 1 Remove the vacuum chamber lid and radiation shield lid section 4 3 1 2 Use the z axis micrometers to raise all probes up 3 mm to 4 mm above the sample stage 3 Slowly move one probe towards the sample stage using the x axis hand dial 4 Watch for interference of the probe cable connector and blades 5 Using the x and y micrometers to adjust posit...

Page 91: ...o section 6 3 5 3 8 7 Vacuum Chamber Leak Test Follow this procedure to verify vacuum chamber integrity 1 Test the turbo vacuum pump along with the connection to the probe station section 6 3 1 2 2 Test the turbo vacuum pump connection to the probe station and the probe station vacuum chamber section 6 3 1 3 Failure to turn off and properly vent the vacuum pump before opening the vacuum isolation ...

Page 92: ...82 CHAPTER 3 Installation and Setup Model CRX 6 5K Probe Station ...

Page 93: ...ssembly when it is not under vacuum D Heating the sample cooling assembly when the CCR is off D Not raising the probe tips before evacuating the chamber D Not raising the probe tips before changing temperature D Not checking that all probe tips can contact the sample under test before cooling down 4 1 2 Temperature Limits The maximum temperature limits for the multiple stages and components of the...

Page 94: ...o the end of its travel Restriction can sometimes also be caused by interference inside the chamber In either case never force one of the controls or damage to the probe or sample cooling assembly may result Instead remove the vacuum chamber lid and radiation shield section 4 3 1 and identify the restriction before proceeding The probe arm translation stage has a greater range of motion than is ac...

Page 95: ...te revolution of the micrometer moves the probe 0 5 mm The graduated scale on the outside of the micrometer shows 0 01 mm divisions For those probe assemblies that are shipped with microwave probes planarization rotation of the probe arm is described in section 4 6 3 Procedures to install the planarization assembly are in section 5 3 8 FIGURE 4 2 Micro manipulated stage illustrating the axes ...

Page 96: ...e 4 Recommended connect a tank of dry inert gas such as nitrogen or argon to the purge valve and follow the instructions for purging the vacuum chamber section 4 4 4 Input 6 9 kPa to 13 8 kPa 1 to 2 psi into the chamber during the remainder of this procedure Alternate to release the vacuum to atmosphere slowly open the purge valve by turning the hand knob on the top of the valve counterclockwise 5...

Page 97: ... of the connector 2 Screw the lifter tool into the sample holder There are two holes available for the lifter Use the most convenient FIGURE 4 5 3 Using the 2 5 mm hex driver loosen the four M3 screws Be careful not to drop them inside the chamber 4 Lift the screws out with tweezers or leave them in their holes and lift them out with the sample holder 5 Using the lifter tool lift out the sample ho...

Page 98: ...4 3 3 2 Reducing the Risk of Cracking Wafers Larger whole wafers pose the most difficult challenge for sample mounting Good thermal contact with the sample holder is desirable to prevent thermal gradients across the wafer but because of their size differences in thermal expansion can cause the wafer to crack when cooled There are two common methods for reducing the risk of cracking wafers D Flexib...

Page 99: ... for larger or smaller samples respectively VGE 7031 varnish may be air dried or baked according to manufacturer s recommendations D To remove you can remove the sample by soaking in ethanol or toluene A solution of equal parts of ethanol and toluene has also been very successful at removing samples mounted with VGE 7031 varnish Grooves in the sample holder permit the remover to flow under the sam...

Page 100: ...ool FIGURE 4 6 5 If you are mounting an optional triaxial or coaxial sample holder align the socket on the sample holder with the cable location 6 Using the 2 5 mm hex driver fasten the sample holder to the sample stage by starting all four M3 screws in a few threads before tightening any screws to pre vent cross threading 7 Tighten the four screws securely this is the source of thermal contact be...

Page 101: ...eld body 3 Clean the o ring groove in the vacuum chamber Clean inspect and lightly grease the o ring with vacuum grease and place it in the groove FIGURE 4 8 Make sure that the o ring does not twist as it is being installed 4 Place the vacuum chamber lid onto the o ring FIGURE 4 8 5 Push down squarely on the vacuum chamber lid and turn the quarter turn fas teners until they lock into place Do not ...

Page 102: ...ted manually Some turbo pumping systems include an automatic venting feature for the turbo pump but most are manual Specific instructions for vacuum operation are included in the remainder of this section and section 4 5 General descriptions and recommendations for these controls are given below however your pump manufacturer s recommendations should always take precedence D Purge valve the purge ...

Page 103: ...the gauge located on the vacuum chamber itself For more accurate vacuum pressure readings the gauge can be moved to an available port on the vacuum chamber or as shown in FIGURE 6 4 4 4 1 3 Vacuum Performance A room temperature vacuum level of 10 3 Torr in the vacuum chamber is required for the probe station to meet its specified base temperature and cooling time Each probe station is tested prior...

Page 104: ... should reach full speed in approximately 5 min The chamber should pump below 10 3 Torr in approximately 30 to 60 min If it does not refer to section 6 3 1 8 for troubleshooting At this point in the process operation of the vacuum pump and isolation valve are dependent on the intended application 4 4 3 Shutting Down the Turbo Pump Follow this procedure to shut down the turbo pumping system This pr...

Page 105: ...purge valve fitting A p in NPT to p in OD tube adapter is included in the Model CRX 6 5K spares kit 3 Regulate the gas pressure from 6 89 kPa to 13 79 kPa 1 psi to 2 psi 4 Open the purge valve slowly until it is fully open In about 1 min the pressure relief valve on the chamber will open and release gas 5 Open the vacuum chamber lid for sample exchange with the gas flowing The dry gas will prevent...

Page 106: ...asurements is to allow the entire CRX 6 5K station to cool to base temperature and then to warm the sample stage to the desired measurement setpoint 4 5 1 Controls for Temperature Operation The Model CRX 6 5K uses the CCR and two electronic control loops one for each stage to establish and regulate temperature This section details the CCR controls first followed by the electronic controls 4 5 1 1 ...

Page 107: ...be set to zero or the heaters should be turned off The sample stage control operates with different control settings at different temperatures Nominal values for operation are described in each of the following sections and summarized in the temperature controller configuration table TABLE 4 2 Some adjustments to these settings will be required during operation Control of the other three stages is...

Page 108: ...ple stage to elevated temperatures The turbo pump should remain running at all times to maintain proper vacuum in the chamber any time the sample stage is heated above 77 K To minimize the heat load at the sample turn the microscope light down or off This procedure assumes that you have cooled the probe station to base temperature and wish to bring it up to the temperature your experiment requires...

Page 109: ... the vacuum isolation valve f Turn off and vent the turbo vacuum pump section 4 4 3 4 5 5 Temperature Control Summary The temperature controller configuration table TABLE 4 2 and the CCR and electronic control settings table TABLE 4 4 and TABLE 4 5 summarize the typical settings needed to maintain the Model CRX 6 5K temperature control TABLE 4 5 provides the sample stage electronic control setting...

Page 110: ...ominal power See TABLE 4 5 100 Radiation shield stage Heater range Off Off Off On 50 W Nominal power 100 TABLE 4 4 General CCR and electronic control settings Sample stage Base to 20 K 20 K to 100 K 100 K to 250 K 250 K to 350 K Nominal power 10 at 10 K 13 at 50 K 21 at 200 K 33 at 350 K Heater range Med High High High Proportional P 100 100 100 100 Integral I 25 25 25 25 Derivative D 0 0 0 0 Heat...

Page 111: ... repeatable 4 6 1 Using the Microscope to Image the Sample Follow this procedure to use the microscope to image the sample 1 Remove the dust cap from the bottom of the microscope 2 Loosen the thumbscrew on the vertical microscope shaft swing the microscope over the center of the viewport and tighten the thumbscrew This process is repeated for fine positioning providing the first axis of motion 3 R...

Page 112: ...he sample Fail ure to do so will potentially cause damage to the probe tip or scratch the sample surface 3 Position the probe tips over the sample or landing pads using the x axis hand dial and y axis micrometer 4 Swing the microscope over the viewport 5 Adjust the microscope to fill the monitor with the sample image and focus at the height of the landing pads or landing surface 6 Use the z axis m...

Page 113: ...bstrate prior to evacuating and cooling the system Gold plated pads are specifically recommended because the following procedure requires landing the probe on the substrate and visually verifying landing marks Soft gold plating allows the landing marks to be more visible 4 6 3 1 Adjusting the Angle of the Planarization Assembly Follow this procedure to planarize a microwave probe any time it has b...

Page 114: ...on the metallization 7 If the adjustment range of the differential knob is inadequate the probe must be manually rotated in the probe arm inside the vacuum chamber by loosening the probe arm set screws and manually rotating the probe body Once the probe has been properly planarized raise the probe 3 mm to 4 mm to avoid damage 8 Carefully tighten the four M4 screws holding the bellows flange to the...

Page 115: ...m the surfaces and can be pumped out more quickly The Model CRX 6 5K cannot be baked out because its components will not tolerate the high temperatures required however controlled warming and cycle purging can improve vacuum integrity The following procedure can be performed with the sample already in the probe station as long as the sample will not be affected by the elevated temperature or the g...

Page 116: ...he HT sample stage is a coaxially isolated stage that is designed for 51 mm 2 in diameter wafers The HT stage option installa tion and removal from the Model CRX 6 5K probe station is similar to the sample holder installation and removal The HT sample stage has a platinum sensor embed ded in the top sample plate that is calibrated from 6 K up to 675 K for rated tempera ture operation in the Model ...

Page 117: ... which has a corresponding 6 pin connection Note the orientation of the guiding lugs and rotate as necessary The outer shell will rotate and click into place for a secure connection 5 2 2 1 2 Reconfigure the Model 336 Temperature Controller for HT Sample Stage Operation 1 Verify that Input D of the Model 336 temperature controller is properly config ured for the HT stage as listed in TABLE 5 1 2 R...

Page 118: ...ample holder removal tool install the HT stage plug into the socket 5 Using a 2 5 mm hex driver tighten the four M3 screws at the base of the HT stage to the sample stage by starting all four screws in a few threads before tightening any screws to prevent cross threading 6 Tighten the four screws securely this is the source of thermal contact between the HT sample stage and the sample stage It is ...

Page 119: ...om the station being care ful of the delicate lead wires Take care not to damage the cryogenic coaxial wire when removing the HT sample stage from the probe station 6 Place the HT stage in a clean secure dry location 5 2 2 4 Reconfiguring the Model CRX 6 5K for Standard Operation Follow this procedure to reconfigure the CRX 6 5K probe station for standard opera tion without the HT sample stage 1 D...

Page 120: ...tentially cause damage to the probe tip or scratch the sample surface 2 Use the controller settings given in TABLE 5 2 for operating the HT sample stage above base temperature to set the P I and D and to set the proper heater range for the temperature setpoint 3 Change the setpoint for the HT sample stage Model 336 temperature controller Output 1 to the desired temperature Do not operate the HT sa...

Page 121: ...m hex driver unscrew the four M4 screws from the arm port blank on the vacuum chamber if present Remove the blank and set it aside 6 Clean the o ring groove in the probe arm port FIGURE 5 6 Clean inspect and lightly grease the o ring with vacuum grease and place it in the groove 7 Slide the stage onto the probe arm location and carefully guide the cable and probe arm through the arm port FIGURE 5 ...

Page 122: ...maining two M4 diagonally opposing screws c Fully tighten the first two diagonally opposing M4 screws that attach the bellows to the vacuum chamber d Using the x axis hand dial move the probe arm stage forward toward the vacuum chamber e Fully tighten the remaining two M4 screws that attach the bellows to the vacuum chamber 11 Attach the arm shield braids to the radiation shield a Use tweezers to ...

Page 123: ...ction 3 7 5 respectively Do not remove optical fiber probes they should be left in place 3 Use a 7 mm wrench to loosen the hex screws that hold the spade lugs at the ends of the arm shield braids to the radiation shield FIGURE 5 9 but do not fully remove these screws Slide the spade lugs from under the screw heads and let the arm shield braids fall 4 Using a 3 mm hex driver remove the four M4 scre...

Page 124: ... location as directed in section 5 3 2 Follow this pro cedure to remove a probe arm and base 1 Using a 3 mm hex driver loosen and remove the four long M4 horizontal screws that attach the bellows to the z axis stage FIGURE 5 12 2 Grasp the square end flange of the bellows and with a twisting motion work the bellows end flange off the probe arm base This should be done slowly and with a great deal ...

Page 125: ... arm base is loosely secured to the z axis stage with two stainless steel threaded dowels Unscrew the threaded dowels and then pull both dowels out FIGURE 5 13 Access to the threaded dowels may be to the side of the z axis stage as shown in FIGURE 5 13 or to the top of the z axis stage 6 Lift the probe arm and base off the z axis stage Pull the probe arm and base out of the stage FIGURE 5 12 Left ...

Page 126: ...ptured by the dowels It is free to rotate even when you secure the dowels 3 If you do not have a planarization assembly using a 3 mm hex driver tighten the M4 screw to secure the stabilization bracket to the probe arm base FIGURE 5 14 4 If you have a planarization assembly using a 2 5 mm hex driver tighten the two M3 screws to secure it to the probe arm base FIGURE 5 15 5 If the probe arm has a fl...

Page 127: ...e the probe arm and base using the instructions in section 5 3 3 3 Using a 2 5 mm hex driver remove the four M3 screws that attach the cable feed through assembly to the probe arm base FIGURE 5 17 4 Remove any ties or tape securing the coaxial cable to the probe arm 5 Lift the cable feedthrough assembly from the probe arm base 5 3 5 2 Installing an Ultra miniature Cryogenic Coaxial Cable Ultra min...

Page 128: ... the end of the probe arm b Thread the SMA completely onto the ZN50 probe ensuring there is no ten sion on the coaxial cable c If the cable is not long enough cut the dental floss ties unwrap 1 to 2 coils of the coaxial cable and repeat steps 5 and 6 until the fit is correct d Remove the ZN50 probe to prevent damage to the probe tip 8 Install the probe arm and base using the steps in section 5 3 4...

Page 129: ...e cable is removed 5 3 6 2 Installing a Microwave Cable Semirigid cables are used with microwave probes Follow this procedure to install a semirigid cable onto a probe arm assembly 1 Clean the o ring groove of the cable feedthrough in the probe arm base Clean inspect and lightly grease the o ring with vacuum grease and place it in the groove 2 Carefully insert the cable into the probe arm base Con...

Page 130: ...ese are listed in order of increasing difficulty The more difficult methods allow for more adjustment range First Method Rotate the Cable Feedthrough Assembly 1 Remove the micro manipulated stage following the steps in section 5 3 2 2 Optional Remove the bellows following steps 1 to 2 in section 5 3 3 3 Remove the top set of four M3 screws holding the cable feedthrough to the feedthrough tower FIG...

Page 131: ...irst method of this section for a final adjustment 6 Test the fit If there is not enough adjustment with this method go to the third method 7 Install the probe arm and base to the micro manipulated stage using the instruc tions in section 5 3 4 8 Install the micro manipulated stage to the probe station using the instructions in section 5 3 1 Third Method Adjust the Arm Length 1 Remove the micro ma...

Page 132: ...ttached optical fiber out of the probe arm Handle the fragile optical fiber carefully it should not be bent sharply or it may break 7 If you are changing probe types remove the feedthrough extension and probe mount as necessary 5 3 7 2 Installing an Optical Fiber Assembly The optical fiber assembly includes the optical fiber terminations and feedthroughs To remove the optical fiber reference secti...

Page 133: ...ng a 2 5 mm hex driver attach the feedthrough to the feedthrough extension with four M3 screws 10 Loosely wrap the fiber around the probe arm to take up any slack 11 Insert the optical fiber tip into the opening in the probe mount FIGURE 5 25 12 Using a 2 5 mm hex driver secure the tip by gently tightening the M3 screw FIGURE 5 25 FIGURE 5 23 Left Attaching the feedthrough extension to the probe a...

Page 134: ...ing section 5 3 1 16 Attach the braid block following step 5 a to c in section 3 7 2 1 17 Before initiating a cryogen transfer test probe arm reach It is very costly and time consuming to initiate cool down only to find the probe mount braids pre vent full probe travel FIGURE 5 25 Left Inserting the optical fiber tip into the opening in the probe mount Right Securing the optical fiber tip by tight...

Page 135: ...o the probe arm base can rotate FIGURE 5 27 Simply loosen them two to three rotations do not remove them 3 Remove the lock nut from the end of the planarization assembly 4 With the mounting holes on the planarization assembly bracket facing the mounting holes on the probe arm base thread the shaft through the hole for the planarization assembly shaft FIGURE 5 28 5 When the mounting holes in the br...

Page 136: ...que of 112 N mm 16 in ounces The torque required is much lower than one might think would be needed We recommend using a torque wrench to ensure these screws are not over torqued If these screws are over torqued the z axis stage and bel lows may be damaged FIGURE 5 29 Left Thread the nut onto the bottom of the shaft Right Tighten the four long horizontal M4 screws ...

Page 137: ...e Tailor the schedule to fit your own probe station use Maintenance Every use 3 months 6 months 12 months As needed Maintain a safe clean work space Clean the top surface of the sample holder Inspect for condensation during cooling Observe changes in cooling behavior Close and evacuate the vacuum chamber when finished Clean the inside of the vacuum chamber Clean the sample holder Pump out the cham...

Page 138: ...lid D Radiation shield lid D Main chamber o ring D Sample holder D Probes 2 Wipe down the following surfaces with a lint free wipe like Kimwipes and isopropyl alcohol Do not clean the viewports during this step D Top edge of the radiation shield mating surface D Mating surfaces of the radiation shield lid D Any surface that shows fingerprints D Any surface likely touched during sample exchange D S...

Page 139: ... anti fog solution to a small folded optical cloth 2 Wipe onto the surface of the viewport using a circular and overlapping motion 3 Allow the solution to dry until a slight haze appears 4 Apply a second coat using a new cloth and fresh solution to ensure complete and uniform coverage 5 Remove the final haze with a clean dry cotton cloth 6 2 5 O Ring Maintenance O rings are generally reliable and ...

Page 140: ...ct Lake Shore service before attempting to drop the sample cooling assembly if you suspect a leak Vacuum chamber base feedthroughs there are a number of electrical and mechanical feedthroughs located on the base of the vacuum chamber and each contains an o ring The seals on these feedthroughs are not normally broken during reconfiguration of the probe station Please contact Lake Shore service befo...

Page 141: ...ted States The probe tips are very delicate Do not touch them during this procedure Failure to comply may result in damaged or broken probe tips Follow this procedure to clean BeCu probe tips 1 Wearing gloves remove the probe from the probe arm 2 Place a small drip cup under the probe tip 3 Wearing gloves dispense one full strength drop of liquid tarnish remover just above the probe tip letting th...

Page 142: ... the probe backwards 1 mm Thisprocessquickly removes the oxide but also removes someof the tipmaterial and can result in reduced probe life 4 After removing oxidation clean the probe as described in section 6 2 8 1 6 2 9 Probe Arm Maintenance The probe arms and stages require very little maintenance however some of the fasteners do need to be re tightened periodically due to thermal cycling or rep...

Page 143: ... your local representative to obtain a replacement adsorber Refer to the HC 4E1 Compressor Unit Technical Instruction for the manufacturer s part number and specific instructions on changing the adsorber 6 2 11 Vacuum Pump Maintenance It is difficult to give specific instructions for all possible combinations of pumps that may be used with the Model CRX 6 5K Refer to the information included with ...

Page 144: ...off and properly vent the turbo pump The turbo pump should not be used in this process until all visible water has evaporated from the chamber 3 Allow all stages to warm to room temperature 300 K The temperature control lers can be used for warm up but they should be monitored closely in case any of the sensors were damaged Never heat any part of the probe station sample cooling assembly above roo...

Page 145: ...ge located on the chamber If your vacuum does not perform similar to the curve illustrated in FIGURE 6 2 the following sections describe some common problems and simple diagnostic procedures to remedy this If the problem is caused by a very small leak it may be necessary to use a leak detector to troubleshoot it properly Leak detector operation is not covered in this manual Consult your leak detec...

Page 146: ...ping 6 Do not continue to the next steps if this pressure is not achieved contact Lake Shore or your vacuum pump manufacturer directly for technical assistance 7 If 10 6 Torr is achieved turn off the turbo pump and vent the turbo 6 3 1 2 Testing the Vacuum Pumping System Along with the Connection to the Probe Station 1 Remove the NW 40 blank off plate from the inlet T on the vacuum pumping system ...

Page 147: ...are functioning properly 9 Continue through the remainder of section 6 3 1 and if these pressures are not achieved contact Lake Shore for technical assistance 6 3 1 4 The Impact of Cryopumping Any time the sample cooling assembly is cold gas molecules in the chamber will freeze onto the cryogen cooled surfaces cryopump An otherwise functioning probe station can cryopump well enough to overcome a p...

Page 148: ...mechanical and should be relatively easy to identify Follow this procedure to find the issue D Open and fully close the purge valve purge valve seats sometimes do not fully close D Close the turbo vent valve if it is not closed automatically D Visually inspect the pressure relief valve to verify that it is properly seated D Check the alignment of the vacuum chamber lid D Verify that the chamber li...

Page 149: ...nd good vacuum practices were not followed D The system has been overheated or operated when not under vacuum D The system has been vented to atmosphere while cold To minimize the effects of contamination D Follow the guidelines in section 6 2 3 D Follow the guidelines in section 6 2 12 Suspect a very small leak if D The pump passed a blank off test D The system is clean and poor vacuum persists D...

Page 150: ...fy that the radiation shield stage temperature control output is off If the radiation shield stage temperature control is off then your problem may be a result of a malfunction with the CCR cold head first stage Stop operation and contact Lake Shore 6 3 3 4 Sample Stage Does Not Reach Base Temperature The Model CRX 6 5K sample stage should be able to cool to within 1 K of base temperature in appro...

Page 151: ... base temperature As the system approaches maximum temperature short term control stability degrades somewhat but should remain below 1 K in a properly tuned system Considerations when regulating with electronic temperature controls When operating with the electronic temperature controllers the following problems may cause unstable or erratic temperature readings D Controller PID parameters are no...

Page 152: ...is required to properly illuminate the sample If a higher output is required or the sample remains too dark at 100 output the light source may be out of alignment To verify proper alignment do the following D Turn off the light source and allow it to cool D Remove the fiber optic bundle from the light source D Remove any dust on the end of the fiber optic bundle D Check that the bulb is centered i...

Page 153: ...ibration Vibration can come from many sources including the CCR itself vacuum pumps motors and fans running in the vicinity of the probe station Vibrations can also affect the microscope directly Make sure the electrical wires and fiber optic bundle going to the microscope are not stretched tight and do not pass over the vacuum line or any other vibration source Isolate the light source from the p...

Page 154: ...t go back through the assembly procedures section 3 6 4 and the earlier parts of section 6 3 4 and try to identify the problem The image obtained with the chamber and shield lids off is better than can be expected with them on The viewport optics will always degrade image quality no matter how well the system is optimized Experiment with different sample materials first with the lids off then add ...

Page 155: ...he probe tips the cautions throughout this manual instruct operators to raise probe tips before cooling or warming the system when applying vacuum and when moving probes in the x or y direction Probes that are damaged when vacuum is applied or while being moved when landed are generally the ones that are very severely damaged Probes damaged during temperature change often take on a characteristic ...

Page 156: ...pplications Not every tip material is compatible with every sample material For more information please reference section 2 3 2 1 Dirty or damaged tips some tip materials especially BeCu form an insulating oxide when exposed to air Tips also get dirty during normal use Bent or damaged tips generally make very poor electrical contact Clean and inspect probe tips for damage regularly For more inform...

Page 157: ... from the sensitive electronic instruments The circuit protection used for the turbo pumping system should be capable of handling high inrush currents The CCR compressor will draw high inrush currents when powered on Circuit protection capable of handling these short duration inrush currents is required to prevent nuisance tripping of the safetydevices Thermal circuit breakers perform best when av...

Page 158: ...um shroud A Red V 4 CCR second stage sensor 1 6 pin DIN B Black red V 2 C White I 5 D Black white I 1 No connection Gray tin Cable shield 3 E Red Signal CCR second stage heater 1 Single banana F Black Ground Connector body Gray tin Ground Signalb CCR second stage Single banana G Red V 4 CCR first stage sensor 2 6 pin DIN H Black red V 2 J White I 5 K Black white I 1 No connection Gray tin Cable sh...

Page 159: ...m FIGURE 6 8 shows the system wiring diagram It details the electrical interconnec tions for the probe station and Model 336 temperature controller Lake Shore part numbers of individual cables are also shown Contact Lake Shore if you need replace ment cables ...

Page 160: ...nnector Probe arm assembly any Input B Rad shield stage Si diode Heater output 1 Sample stage 100 W heater Heater output 2 50 W heater Input C Probe arm Si diode Input D CCR 2nd stage Model 336 sensor connectors typical 5 places Pin Signal 1 I 2 V 3 Sensor cable shield 4 V 5 I 6 NC Input A Sample stage Si diode SENSOR 2 SENSOR 1 SENSOR 1 HEATER 1 Model 336 temperature controller GND DC0616 PROBE A...

Page 161: ... required by the carrier as evidence to support claims Call Lake Shore for return and repair instructions All equipment returns must be approved by a member of the Lake Shore Systems Service department The service engineer will use the information provided in the service request form and will issue a Return Material Authorization RMA Once the RMA has been approved you will receive appropriate docu...

Page 162: ...152 CHAPTER 6 Maintenance and Troubleshooting Model CRX 6 5K Probe Station ...

Page 163: ...ents 46 ground loops 27 groundedsampleholder 21 26 28 cleaning 130 grounding 25 26 27 high impedance measure ments 32 vacuum chamber 26 ground signal ground 19 34 73 guarding 32 configurations for 32 H hall 1 I installation 41 coaxial cable 116 microwave probes 73 optical fiber 121 probe arm and base 115 semi rigid cable 118 translation stage 110 L landing the probe 100 leakage low leakage measure...

Page 164: ...s 41 specifications 1 subsystems 7 unpacking 47 probe tips 17 probes installing a ZN50 68 landing 100 misaligned 74 pitch 19 20 36 removing 68 removing a ZN50 72 troubleshooting 146 probing configurations 17 purge heated cycle purge 103 R radiation shield lid removal 83 RF measurements 29 30 S sample imaging and probing 98 low resistance 31 permanent mounting 87 semi permanent mounting 86 temporar...

Page 165: ...bleshooting 135 Vector Network Analyzer 20 37 vibration 43 56 vibration isolation 67 low noise measurements 31 viewport window maintenance 129 vision system 16 assembly 61 power requirements 147 troubleshooting 142 unpacking 51 voltage biasing 30 33 W warm up purging 92 removingcondensation 134 sensors and heaters 10 water requirements 45 wiring diagram 149 Z ZN50 compatible probe cables 18 ZN50 c...

Page 166: ...156 INDEX Model CRX 6 5K Probe Station ...

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Lake Shore Cryotronics CRX-6.5K, User Manual

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