Standard Operation Procedure for Plasma Enhanced Chemical Vapor Deposition
Purpose: to deposit a layer of various materials onto the surface of the sample
Location: Marcus and Pettit Cleanrooms
Supplies Needed: test wafer/ wafer pieces, witness wafer/ wafer piece (if necessary), tweezers
Tools Available: Plasma Therm PECVD, Uxaxis PECVD, STS PECVD 1&2, Oxford ICP PECVD, Oxford PECVD 1&2
Setup Procedures:
1. Schedule time well in advance
2. Check that both the front and back sides of the wafer are clean and free of any debris. (see wafer cleaning section)
a. No photoresist allowed in PECVDs
3. Check that the clean recipe has been run on the tool
4. If the clean recipe was not run, start the clean process
a. Chamber cleanliness can be determined by monitoring the DC bias. Each machine has a DC bias that is typical of a clean chamber. This should be noted before tool use.
5. After the clean recipe is done, vacuum the chamber and wipe down the o-ring with a dry texwipe
6. Run a seasoning run on the tool
a. Run the recipe you intend to run without a sample, and deposit at least 2000 Angstroms to condition the chamber for the recipe
7. Run a deposition test on the tool
a. Using an extra clean wafer or wafer piece, run the tool for a few minutes (typically 2-3 minutes is fine).
b. Measure the deposition with an ellipsometer or reflectometer, and determine the deposition rate
c. Calculate how long the process step must be run for the deposition thickness desired
Number of Substrates: < 1 – 4 (4” samples)
Process Procedures:
1. Load the sample and a witness sample (if possible) into the tool and run the process
2. Watch the take notes on the parameters
a. Both set point and actual values
b. If the reflected power is high (2 watts+) stop the recipe and run the clean process again
3. Check and note the color of the plasma
a. Changes in color could be due to contamination
b. If contaminated, unload your sample and run the clean process
4. Measure the deposition to make sure it is what was expected
a. If the deposition is less than expected:
i. Calculate the deposition rate for the full run
ii. Place the wafer back into the tool and run using the new deposition rate to determine the time needed
5. Run the clean recipe on the tool after removing the sample
a. Stay by the tool until the plasma strikes
b. Run it for the full clean time
6. Log off the tool and cancel any scheduled time that was not used