STS Pegasus 4/Processes/LNF O2 Descum
LNF O2 Descum (previously known as LNF ASH) uses an O2 plasma to isotropically remove polymers. It is intended as a photoresist descum prior to etching, although it may oxidize expose surfaces. The LNF Ar Descum is better suited for normal circumstances. This recipe may also be used for photoresist mask stripping post process, although there are other systems at the LNF with better performance for this process.
| About this Process | |
|---|---|
| Process Details | |
| Equipment | STS Pegasus 4 |
| Technology | RIE |
| Material | all |
| Mask Materials | none |
| Gases Used | O2 |
Contents
Procedure
Follow the standard operating procedure. This recipe may also be added as an additional step within another recipe. Create a helpdesk ticket for assistance.
Parameters
| Parameter | Units | Setpoint |
|---|---|---|
| ICP Power | W | 2500 |
| Bias Power (LF) | W | 75 |
| Bias Pulsing | Hz | none |
| Pressure | mTorr | 20 |
| O2 Flow | sccm | 200 |
| Ar Flow | sccm | 100 |
Capabilities
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 |
|---|---|---|
| SPR 220 | 7800 Å/min | 6% |
| Silicon dioxide | 30 Å/min | 5% |
| Silicon nitride | 22 Å/min | 5% |
| Low stress nitride | 20 Å/min | 5% |
| Silicon | 15 Å/min | 5% |
Mask Selectivity
This recipe is intended for blanket descum of the wafer surface, so a mask is not necessary.
Limitations
Maximum allowed etch time is 5 min.