MAINTENANCE
5.8 Tube change LPCVD and vacuum system tubes
CAUTION
Use cleanroom gloves for handling quartz.
The tube exchange is required at the moment there has been a deposition of approx. 20 microns.
This however is strongly depending on the particle additions at processing. In case the particles get
above spec, the tube should be exchanged.
At every tube change the following has to be done:
1. Cool the system down to room temperature.
2. Remove the cantilever paddle.
Must be cleaned
.
3. Untighten the screws of the front flange of the process tube.
4. Open the door to the heating element and pull the Thermocouples 5 cm out.
5. Take the Profiling TC out of the tube.
Must be cleaned
.
6. Remove the Pressure Switch.
7. Remove tube adapters and radiation heatshields.
8. Remove the ball joint clamp and the clamp of the vacuumline and move the vacuumline
away.
Vacuumline must be cleaned
.
9. One engineer should be at the loading side and one at the rear of the system.
10. Pull the tube 2 cm to the rear so that the engineer at the loadside can take the O ring
from the tube.
Front flange must be cleaned
.
11. Gently pull the tube out of the system, while the engineer at the loadside guides the tube
out, while lifting it up so it does not scratch on the element.
Tube must be cleaned
.
12. At each tube change that is done after a number of process runs, the Mass Vac Dust trap
must be cleaned, and all new filter elements must be fitted!
13. When putting the system back together again, use the opposite procedure and:
14. Use only new O-rings on all the seals, flange, ball joint, profile TC, vacuum line, etc.
15. Clean all the vacuum flanges and o rings with isopropyl alcohol.
16. Use only cleaned quartz tube and cleaned profile TC.
17. Check the adjustment of the vacuum atmosphere switch.
18. Check system base pressure - must be < 5 mtorr at 20 degrees C.
19. Check system leakup rate - must be < than 10 mtorr / min.
20. After every tube change the system must be profiled and after profiling a coating run
should be done (for deposition systems only) and the system profiled again after coating.
21. Check system leakup rate at standby temperature.
22. Check system for any alarms.
23. System is ready for processing
F
URNACE
R
EFERENCE
M
ANUAL
5-6
