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[6]  Handling Guide 

 

110 

3.4.2 Inspection 

Sequence 

1.  Do not insert devices in the wrong orientation. Make sure that the 

positive and negative electrodes of the power supply are correctly 
connected. Otherwise, the rated maximum current or maximum power 
dissipation may be exceeded and the device may break down or undergo 
performance degradation, causing it to catch fire or explode, resulting in 
injury to the user. 

2.  When conducting any kind of evaluation, inspection or testing using AC 

power with a peak voltage of 42.4 V or DC power exceeding 60 V, be sure 
to connect the electrodes or probes of the testing equipment to the device 
under test before powering it on. Connecting the electrodes or probes of 
testing equipment to a device while it is powered on may result in electric 
shock, causing injury. 

 

(1)  Apply voltage to the test jig only after inserting the device securely into it. When applying or 

removing power, observe the relevant precautions, if any. 

(2)  Make sure that the voltage applied to the device is off before removing the device from the test jig. 

Otherwise, the device may undergo performance degradation or be destroyed. 

(3)  Make sure that no surge voltages from the measuring equipment are applied to the device. 
(4)  The chips housed in tape carrier packages (TCPs) are bare chips and are therefore exposed. 

During inspection take care not to crack the chip or cause any flaws in it. 
Electrical contact may also cause a chip to become faulty. Therefore make sure that nothing 
comes into electrical contact with the chip. 

 

3.5 Mounting 

There are essentially two main types of semiconductor device package: lead insertion and surface 

mount. During mounting on printed circuit boards, devices can become contaminated by flux or 
damaged by thermal stress from the soldering process. With surface-mount devices in particular, the 
most significant problem is thermal stress from solder reflow, when the entire package is subjected to 
heat. This section describes a recommended temperature profile for each mounting method, as well as 
general precautions which you should take when mounting devices on printed circuit boards. Note, 
however, that even for devices with the same package type, the appropriate mounting method varies 
according to the size of the chip and the size and shape of the lead frame. Therefore, please consult 
the relevant technical datasheet and databook. 

 

3.5.1  

Lead 

Forming 

 

1.  Always wear protective glasses when cutting the leads of a device with 

clippers or a similar tool. If you do not, small bits of metal flying off the 
cut ends may damage your eyes. 

2.  Do not touch the tips of device leads. Because some types of device have 

leads with pointed tips, you may prick your finger. 

 

Semiconductor devices must undergo a process in which the leads are cut and formed before the 

devices can be mounted on a printed circuit board. If undue stress is applied to the interior of a device 
during this process, mechanical breakdown or performance degradation can result. This is 
attributable primarily to differences between the stress on the device’s external leads and the stress 

Содержание Semiconductor

Страница 1: ...ucts specifications Also please keep in mind the precautions and conditions set forth in the Handling Guide for Semiconductor Devices or TOSHIBA Semiconductor Reliability Handbook etc The TOSHIBA products listed in this document are intended for usage in general electronics applications computer personal equipment office equipment measuring equipment industrial robotics domestic appliances etc The...

Страница 2: ...u move on to the detailed descriptions of the precautions Explanation of labels Indicates an imminently hazardous situation which will result in death or serious injury if you do not follow instructions Indicates a potentially hazardous situation which could result in death or serious injury if you do not follow instructions Indicates a potentially hazardous situation which if not avoided may resu...

Страница 3: ... device is on do not touch the device s heat sink Heat sinks become hot so you may burn your hand Do not touch the tips of device leads Because some types of device have leads with pointed tips you may prick your finger When conducting any kind of evaluation inspection or testing be sure to connect the testing equipment s electrodes or probes to the pins of the device under test before powering it...

Страница 4: ...area are grounded to earth Place a conductive mat over the floor of the work area or take other appropriate measures so that the floor surface is protected against static electricity and is grounded to earth The surface resistivity should be 104 to 108 Ω sq and the resistance between surface and ground 7 5 105 to 108 Ω Cover the workbench surface also with a conductive mat with a surface resistivi...

Страница 5: ...gs that are made of anti static materials or materials which dissipate electrostatic charge Make sure that cart surfaces which come into contact with device packaging are made of materials which will conduct static electricity and verify that they are grounded to the floor surface via a grounding chain In any location where the level of static electricity is to be closely controlled the ground res...

Страница 6: ...s and devices in canister type packages which have empty space inside them are subject to damage from vibration and shock because the bonding wires are secured only at their ends Plastic molded devices on the other hand have a relatively high level of resistance to vibration and mechanical shock because their bonding wires are enveloped and fixed in resin However when any device or package type is...

Страница 7: ...ul especially corrosive gases or in dusty conditions Use storage areas where there is minimal temperature fluctuation Rapid temperature changes can cause moisture to form on stored devices resulting in lead oxidation or corrosion As a result the solderability of the leads will be degraded When repacking devices use anti static containers Do not allow external forces or loads to be applied to devic...

Страница 8: ...peration even for an instant Although absolute maximum ratings differ from product to product they essentially concern the voltage and current at each pin the allowable power dissipation and the junction and storage temperatures If the voltage or current on any pin exceeds the absolute maximum rating the device s internal circuitry can become degraded In the worst case heat generated in internal c...

Страница 9: ...sumption in comparison with bipolar digital ICs and therefore it only needs a low capacity power supply However in practice CMOS consumes power during transition and therefore it is necessary to keep the high frequency impedance of the power source at a low level It is advisable to make the wiring of the power source VCC and GND lines thick and short and insert as a high frequency filter a capacit...

Страница 10: ...o the output and both flow out IOH and flow in IOL current drive is possible For this reason excessive current will flow in a C2MOSTM output when the high level output line is shorted to the GND line or when the low level output line is shorted to the VCC line In particular when the supply voltage is high IOH and IOL are excessive and may damage the device care must be taken not to cause an output...

Страница 11: ...ue to their physical and electrical characteristics the Mini MOS Series are apt to cause overshoot and undershoot this leads to malfunction of the circuit or the breakdown of passive ICs These problems can be prevented to some extent by terminating the signal line Figure 3 4 shows examples of termination a Termination Using RC Components b Termination Using Diodes Figure 3 4 Examples of Terminatio...

Страница 12: ...to account the timing at power on As the VCC and VSS levels vary from device to device please refer to the datasheet for the device in question 2 Do not subject the device to abnormal noise 3 Fix the potential of any unused input pins to VCC or VSS 4 Do not connect output pins directly to other output pins or to VCC or VSS Since ample margin against latch up is provided there is no problem if Min ...

Страница 13: ...ms are malfunction due to induced noise or destruction of the input output elements due to a surge Reducing the signal line impedance driving impedance or inserting noise eliminating circuits on the receiving side are two ways of dealing with the former problem surge protection measures are taken to cope with the latter Figure 3 7 shows an example of noise and surge protection Alternatively the PC...

Страница 14: ...that the timing requirements specified in the data sheet be observed When a synchronous signal is used care must be taken with the output signal Figure 3 8 shows an example of how to solve this problem In this case if the difference in phase between CK1 and CK2 is the same as the tpd output clock of the first stage flip flop care must be taken Note If CK1 and CK2 cannot be used together the synchr...

Страница 15: ...ich θja thermal resistance between junction and surrounding air C W θjc thermal resistance between junction and package surface or internal thermal resistance C W θca thermal resistance between package surface and surrounding air or external thermal resistance C W Tj junction temperature or chip temperature C Tc package surface temperature or case temperature C Ta ambient temperature C P power dis...

Страница 16: ...anate from each component in a piece of equipment For this reason it is only after the prototype equipment has been completed that the designer can take measurements using a dedicated instrument to determine the strength of electromagnetic interference waves Yet it is possible during system design to incorporate some measures for the prevention of electromagnetic interference which can facilitate ...

Страница 17: ...ic field surface leakage may occur due to the charge up phenomenon resulting in device malfunction In such cases take appropriate measures to prevent this problem for example by protecting the package surface with a conductive shield 3 With some microcomputers and MOS memory devices caution is required when powering on or resetting the device To ensure that your design does not violate device spec...

Страница 18: ... faulty Therefore make sure that nothing comes into electrical contact with the chip 3 5 Mounting There are essentially two main types of semiconductor device package lead insertion and surface mount During mounting on printed circuit boards devices can become contaminated by flux or damaged by thermal stress from the soldering process With surface mount devices in particular the most significant ...

Страница 19: ...e Also avoid bending or stretching device leads repeatedly Be careful not to damage the lead during lead forming Follow any other precautions described in the individual datasheets and databooks for each device and package type 3 5 2 Socket Mounting 1 When socket mounting devices on a printed circuit board use sockets which match the inserted device s package 2 Use sockets whose contacts have the ...

Страница 20: ...gure 3 10 Heating Top and Bottom with Long or Medium Infrared Rays Complete the infrared ray reflow process within 30 seconds at a package surface temperature of between 210 C and 240 C Refer to Figure 3 11 for an example of a good temperature profile for infrared or hot air reflow Figure 3 11 Sample Temperature Profile for Infrared or Hot Air Reflow 3 Using hot air reflow Complete hot air reflow ...

Страница 21: ...methods When immersing devices in a solvent or steam bath make sure that the temperature of the liquid is 50 C or below and that the circuit board is removed from the bath within one minute 5 Ultrasonic cleaning should not be used with hermetically sealed ceramic packages such as a leadless chip carrier LCC pin grid array PGA or charge coupled device CCD because the bonding wires can become discon...

Страница 22: ...e cleaned However if the flux used contains only a small amount of halogen 0 05 W or less the devices may be used without cleaning without any problems 3 5 6 Circuit Board Coating When devices are to be used in equipment requiring a high degree of reliability or in extreme environments where moisture corrosive gas or dust is present circuit boards may be coated for protection However before doing ...

Страница 23: ... due to the occurrence of electrostatic discharge Unless damp proofing measures have been specifically taken use devices only in environments with appropriate ambient moisture levels i e within a relative humidity range of 40 to 60 3 6 3 Corrosive Gases Corrosive gases can cause chemical reactions in devices degrading device characteristics For example sulphur bearing corrosive gases emanating fro...

Страница 24: ...ll adversely affect a device s electrical characteristics To avoid this problem do not use devices in dusty or oily environments This is especially important for optical devices because dust and oil can affect a device s optical characteristics as well as its physical integrity and the electrical performance factors mentioned above 3 6 8 Fire Semiconductor devices are combustible they can emit smo...

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