STS Pegasus 4/Processes/LNF Ar Descum

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About this Process
Process Details
Equipment STS Pegasus 4
Technology RIE
Material all
Mask Materials none
Gases Used Argon
Date Modified 7/25/2017
Authored By Kevin Owen

LNF Ar Descum uses an Ar plasma to anisotropically and indiscriminately remove a thin layer of any material on the surface of the sample. It is intended as a combination of photoresist descum and native oxide removal prior to Si etching. This recipe is already included in all of the standard recipes.


LNF Ar Descum is included as the first process step in all standard processes, so it is not typically necessary to run as a standalone process.

The maximum etch time allowed for this process is 2 minutes.


Parameter Units Setpoint
ICP Power W 2000
Bias Power (LF) W 80
Bias Pulsing none
Pressure mTorr 5
Ar Flow sccm 100


Etch rate and uniformity

All of the etch rates below (with the exception of photoresist) are characterized using LPCVD or thermal furnace films.

Material Etch Rate Uniformity
Silicon dioxide 100 Å/min 13%
Silicon nitride 110 Å/min 11%
Low stress nitride 115 Å/min 10%
Silicon 135 Å/min 20%
SPR 220 190 Å/min 8%

Mask Selectivity

This recipe is intended for blanket descum of the wafer surface, so a mask is not necessary.


Maximum allowed etch time is 2 min.