Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Silicon Nitride Etch using AOE
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Silicon nitride etch with STS recommended silicon nitride recipe
| Parameter | Recipe name: Si3N4_res (Si3N4 etch with resist mask) |
|---|---|
| Coil Power [W] | 1300 |
| Platen Power [W] | 350 |
| Platen temperature [oC] | 0 |
| He flow [sccm] | 174 |
| CF4 flow [sccm] | 40 |
| Pressure [mTorr] | 4 |
| Typical results | Test Results |
|---|---|
| Etch of Si3N4 with DUV mask | See images here |
| Etch rate of Si3N4 | ~435nm/min (50% etch load) |
| Etch rate of Silicon | ~264nm/min (50% etch load) |
| Etch rate of DUV resist] | ~600nm/min (50% etch load)
|
| Profile [o] | close to 90 degrees see the images |
Silicon nitride etch with the standard silicon oxide etch
The standard recipe for oxide etching with photo resist as masking material is called: SiO2_res. It can also be used for nitride etching- The parameters and results so fare are as follows:
| Parameter | Recipe name: SiO2_res (SiO2 etch with resist mask) |
|---|---|
| Coil Power [W] | 1300 |
| Platen Power [W] | 200 |
| Platen temperature [oC] | 0 |
| He flow [sccm] | 174 |
| C4F8 flow [sccm] | 5 |
| H2 flow [sccm] | 4 |
| Pressure [mTorr] | 4 |
| Typical results | Test Results |
|---|---|
| Etch rate of Silicon rich nitride from furnace B2 | 136nm was etched in 1min (whole wafer) - etched in October 2015 by bghe@danchip |
| Etch of Si3N4 with DUV mask | See images here
|
| Etch rate of thermal oxide | ~230nm/min (5% etch load) |
| Selectivity SiO2 to AZ resist [:1] | ~3 |
| Selectivity SiO2 to DUV resist [:1] | ~2.0 - tested May 2013 by Christian Østergaard @nanotech. |
| Profile [o] | ~90 |
Silicon nitride etch with lower etch rate
Test of etch in silicon nitride (LPCVD). 105nm nitride had to be removed - it was removed after 1min and 40s with a very small over etch in Si.
| Parameter | Recipe name: Nitr_res (Silicon Nitride etch using resist mask) |
|---|---|
| Coil Power [W] | 700 |
| Platen Power [W] | 100 |
| Platen temperature [oC] | 0 |
| CF flow [sccm] | 5 |
| He flow [sccm] | 174 |
| H flow [sccm] | 4 |
| Pressure [mTorr] | 4 |
| Typical results | Resist mask | Resist mask |
|---|---|---|
| Silicon nitride (LPCVD) etch rate | ~60 nm/min | 99-108 nm/min (LN/BGE 20130512) |
| Selectivity to photo resist [:1] | ? | ~between 2.5 and 4.0 (LN/BGE 20130512) |
| Etch rate in Si | ? | ? |
| Etch rate in SiO2 | ? | ? |
| Profile [o] | not tested | not tested |
| Etch uniforminty over a wafer [o] | not tested | ± 1.1% to ±1.8% (Eric Jensen @nanotech, oct. 2013) |
| Images | . | . |
| Comments | . | . |