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Teos2

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 

ALARM ACK twice

 

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

 ALARM ACK once

 

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

ALARM ACK twice

 

Load pump program

 

Run Pump program

 

Measure wafers and log results

 

Disable the furnace on Coral.

 

Process Monitoring and Machine Qualification

Purpose:

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

 

Frequency:

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.

 

Documentation:

Test results are recorded on Coral.

 

Procedure:

  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.


 


 

Measure:

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:

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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