Wafer Scanning/Coating Process Traveler ( combined/less detailed)

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WIP....

The wafers for process calibration are ordered from SVM (https://www.svmi.com/). These are: 4” Si wafers, P/Boron, <100>, 1-30 ohm-cm, 525 +/-25 microns, Polished/Etched, Particles: <=10 @ >=0.3 microns, with low LPD count (LPD= light particle detection, LPD<100).

Scan Before Deposition

Log in (access code is boss).

Scan the wafers using the standard recipes: "UCSB Gain4 (measuring small particles 0.16-1.6um ), and " UCSB Gain2 measuring small particles 1.6-28um).

Record: LPD Cnt (sum of all particles #1- #8), particles #1(0.160-0.213)um, particles #8(1.20-1.60)um, and Haze (region(%), average(ppm), peak(ppm)).

Take a picture of the scan.

Log out.

Wafer Coating Process traveler

Test run on "dummy wafer"

  • Sometimes a deposited film on the first wafer, after seasoning, might have high particle count. It is recommended to run the process on a dummy wafer to catch the particle, before the run on "real wafer". Here are the process instructions:
  • Prepare three 4" Si wafers : for seasoning, deposition (use one of previously scanned Si wafers) and cleaning.
  • Load wafers in a cassette, making sure major flat is facing outside (toward you). Try to align flats for all three wafers.
  • Load/Edit/Verify standard recipes (for seasoning, deposition, and cleaning). You can change ONLY the time in recipes.
  • Example of how to run process for the standard recipe "SiO2 LDR 250°C"
    • Load seasoning recipe " SiO2 seasoning" , time=2min
    • Load deposition recipe "SiO2 LDR 250°C" , time=780 sec
    • Load cleaning recipe "Post dep PD", t=900sec
  • Run the process
  • Unload the wafers once the process is finished
  • Check the particle count on a wafer with SiO2 film
    • If the particle count is normal (LPD<500), you can proceed to your process on "real wafers".
    • If the particle count is high (scan looks bad), you could run longer clean and try again. If the particle count is still high, please contact the tool owner.

Run on "real wafer"

  • This tool requires : seasoning, deposition and cleaning for each film you want to deposit.
  • There is a seasoning recipe for both nitrides (SiN Seasoning, t=5min), and a seasoning recipe for both oxides (SiO2 seasoning, t=2min))
    • The goal of seasoning step is to prepare the chamber for deposition (deposit ~200nm of film on walls).
  • There are standard recipes for deposition:
    • "SiO2 LDR film @250°C" time=780sec)
    • "SiO2 HDR film @250°C" time=180sec)
    • "SiN film @250°C " time=480sec)
    • "SiN LS film @250°C " (seasoning 2min, deposition=180sec)
  • There is one recipe for cleaning named as "Post-Dep Clean". You must edit the Post-Dep Clean recipe to correspond to your deposited thickness and material.
    • SiNx etches at 20nm/min (clean should be ~1500sec for 500nm thick film)
    • SiO2 etches at 40nm/min (clean should be ~750sec for 500nm thick film)

Scan After process calibration

Log in (access code is boss).

Scan the wafers using the standard recipes: "UCSB Gain4 (measuring small particles 0.16-1.6um ), and " UCSB Gain2 measuring small particles 1.6-28um).

Record: LPD Cnt (sum of all particles #1- #8), particles #1(0.160-0.213)um, particles #8(1.20-1.60)um, and Haze (region(%), average(ppm), peak(ppm)).

Take a picture of the scan.

Log out.

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