PECVD Recipes

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Back to Vacuum Deposition Recipes.

PECVD 1 (PlasmaTherm 790)

PECVD 1 Process Control Plots - Plots of all process control data

SiO2 deposition (PECVD #1)

SiN deposition (PECVD #1)

Low Stress Si3N4 (PECVD#1)

plot of SiN stress and Refractive Index vs. N2 flow.
Example of Si3N4 modified stress via. varying N2 flow.  Refractive index is relatively constant (one outlier), and stress varies continuously from tensile to compressive.  (Demis D. John 2011, Blumenthal Group)

SiOxNy deposition (PECVD #1)

Standard Cleaning Procedure (PECVD #1)

The cleaning procedure is very important in order to have consistent result on this tool and also to keep particulate count low. After each deposition you should clean the tool following instructions carefully. The clean is done in two steps:

  1. Wet cleaning (start cleaning by using a cleanroom wipe sprayed with DI. Wipe chamber sidewalls with it. Finish cleaning by using the cleanroom wipe sprayed with IPA. )
  2. Load the recipe for cleaning "CF4/O2 Clean" (edit the recipe and change ONLY time of cleaning). Follow instructions regarding a required time for cleaning.
Table of Cleaning Times
Film Dep'd Cleaning Time
SiO2 TBD
Si3N4 TBD
SiOxNy Same as XYZ

Standard Cleaning Recipe (PECVD#1): "CF4/O2 Clean"

Click the above link for a screenshot of the standard cleaning recipe, for which you will enter a custom time. The recipe is set up so that it will pop up a window for the cleaning time upon running the recipe - you do not need to edit the recipe before running it.

PECVD 2 (Advanced Vacuum)

PECVD 2 Process Control Plots - Plots of all process control data

SiO2 deposition (PECVD #2)

SiN deposition (PECVD #2)

Low-Stress SiN deposition (PECVD #2)

Low-Stress Silicon Nitride, Si3N4 (< ±100 MPa)

Low-Stress SiN 3xTime (PECVD #2)

This Low-Stress SiN recipe is more stable over time (months), because each step is 3x longer (so each compressive/tensile layer is thicker), making it less susceptible to RF ignition delays as the grounding strap is etched over time. – 2024-09 Demis & Biljana

Amorphous-Si deposition (PECVD #2)

Standard Cleaning Procedure (PECVD #2)

The cleaning procedure is very important in order to have consistent result on this tool and also to keep particulate count low. After each deposition you should clean the tool following instructions carefully. The clean is done in two steps:

  1. (If >29min dep time) Wet cleaning: Start cleaning by using a cleanroom wipe sprayed with DI. Wipe upper chamber sidewalls with it. Finish cleaning by using the cleanroom wipe sprayed with IPA & wiping again.
  2. Load the recipe for cleaning "STD CF4/O2 Clean" (edit the recipe and change ONLY time of cleaning). Follow instructions regarding required time for cleaning.

Standard Clean Recipe (PECVD#2): "STD CF4/O2 Clean"

Click the above link for a screenshot of the standard cleaning recipe, for which you will enter a custom time. The recipe is set up so that it will pop up a window for the cleaning time upon running the recipe - you do not need to edit the recipe before running it.


Clean Times (PECVD#2)

Film Deposited Cleaning Time (Dry)
SiO2 1 min. clean for every 1 min. deposition
Si3N4 1 min. clean for every 7 min of deposition
If > 29min total dep time

(Season + Dep)

Wet Clean the Upper Lid/Chamber

DI water then Isopropyl Alcohol on chamber wall & portholes

ICP-PECVD (Unaxis VLR)

2020-02: New recipes have been characterized for low particulate count and repeatability.  Only staff-supplied recipes are allowed in the tool. Please follow the new procedures to ensure low particle counts in the chamber.

The system currently has Deuterated Silane (SiD4) installed - identical to the regular Silicon precursor SiH4, except that it significantly lowers optical absorption in the near-infrared due to shifted molecular vibrations/molecular weights. This gas is more expensive and thus more applicable to optical application than to general-purpose SiN films.

Process Control Data (Unaxis ICP-PECVD)

Low Deposition Rate SiO2 [ICP-PECVD]

High Deposition Rate SiO2 [ICP-PECVD]

Gap-Fill SiO2 [ICP-PECVD]

Recipe designed by Warren Jin, please consider our publication policy if you publish using this recipe. 

NOTE: Please contact tool supervisor before running this recipe - this recipe must often be scheduled to prevent excessive chamber maintenance.

Able to effectively fill ~1:1 and ~1:2 aspect ratio gaps in Silicon and Glass structures (eg. waveguides/optical gratings) with void-free filling.

The recipe uses a high 400W RF Bias to reduce buildup on corners that causes voids during growth.

  • Category = SiO2 GapFill - Std.
  • FLOW: SiO2 GapFill 250C
    • Will run the sequence SiO2 GapFill 250C 450W. Do not change this!
  • STEP (edit TIME only): SiO2 GapFill 250C
  • Deposition rate = 99.968nm/min [9/20/23]

Si3N4 [ICP-PECVD]

Low Stress Si3N4 [ICP-PECVD]

Standard Seasoning Procedure [ICP-PECVD]

You must edit the seasoning recipes (SiO2 Seasoning - Std, SiN seasoning - Std). You are allowed to change only seasoning time [time needed to coat chamber walls with ~200nm of film]. Seasoning recipes:

Standard Cleaning Procedure [ICP-PECVD]

You must edit the Post-Dep Clean recipe to correspond to your deposited thickness and material. See the Operating Procedure on the Unaxis Tool Page for details.

  • SiNx etches at 20nm/min
  • SiO2 etches at 40nm/min

Standard Clean Recipe

General Recipe Notes (Unaxis VLR ICP-PECVD)

  • RF1 = Bias
  • RF2 = ICP Power
  • All recipes start with an Argon pre-clean with 0W bias (gentle), to improve adhesion/nucleation.
  • Maximum SiO2 Dep. thickness allowed: 800nm
    • Above this thickness, you must run a chamber clean/season before depositing more onto your product wafer.
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