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Teos2 allows LPCVD deposition of silicon dioxide, using tetraethyl orthosilicate (TEOS) which can provide a more conformal coating at lower temperature than tylanbpsg films. This is a six inch tube.

Teos2 Furnace Operation (short)


Clean substrates

Diffusion clean with HF last


Enable the furnace on Coral


Verify Pump program running

Go to the furnace and use the STATUS button to verify that the system is in 'RUN' mode and running the “PUMP program”. 

End Pump program 



Verify the Tube is vented

Twenty minutes after the pump program has ended you must manually test that the tube is vented. Push MANUAL on the boat puller, push FAST, then LOOK AT THE TUBE while you hold down OUT. You should immediately see the boat start to come out.  If it does not, stop and wait 10 more minutes and test it again.


Load your program (only after verifying manually that tube is vented)

From TYCOM type "LO  <program name>  <furnace#>" <RET>.  You will be asked to enter the deposit time.


Run program


Load your wafers


Send in tube



Monitor furnace

Take pressure readings during the gross leak check, leak check and the deposition steps of the program and write the values in the logbook.


Unload wafers


End program



Load pump program


Run Pump program


Measure wafers and log results


Disable the furnace on Coral.


Process Monitoring and Machine Qualification


To provide a standard procedure to monitor Poly thickness and uniformity both wafer-to-wafer and within-a-wafer.



To be completed after major maintenance such as a tube change or on a set schedule to be determined or as needed based on user feedback.



Test results are recorded on Coral.



  1.  Use two new 'L' test wafers; <100>, P-type (boron), 10-20 ohm-cm.
  2.  Clean at wbdiff in the following sequence;  5:1:1 H2O:H2O2:NH4OH ten minutes, rinse, 5:1:1 DI;HCl:H2O2 ten minutes, rinse, 50:1 DI:HF 30 sec, rinse, spin dry.
  3.  Load program TEOS2STD into Teos2 furnace.  Time variable is 00:16:00.
  4.  Load wafers into boats using very clean tweezers or vacuum wand.  Load wafers with the major flat up into the boats in the following positions:

1st boat: (Front), 20 empty slots,

1st  two dummies,

1st boat:  two test wafers(slot 23 & 24),

1st boat: one dummy.




Use Nanospec to measure poly thickness at the flat, center, bottom, left and right on each wafer.  Test sites should be no more than about 15mm from the edge of the wafer.

locations on wafer

measure locations



Record results on the on coral. If test’s values aren’t not within 10% of plotted test average, contact the Diffusion Process/Maintenance team.


Save wafers in a box with the date, furnace number, program name and growth time.  They may be re-tested sometime in the future.




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