Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Silicon Nitride Etch using AOE
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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 | Variations over SiO2_res made in 2010 by BGHE See results here |
|---|---|---|
| Etch rate of thermal oxide | ~230nm/min (5% etch load) - etch load dependency see here | ~160-340nm/min |
| Selectivity to AZ resist [:1] | ~3 - etch load dependency [[Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Silicon Nitride Etch using AOE/AOE SiO2 etch load dependency|see here]| | 2.7-4.3 |
| Selectivity to DUV resist [:1] | ~2.0 - tested May 2013 by Christian Østergaard @nanotech. | ? |
| Profile [o] | ~90 | 83-90 |
| Images | See here | See here |
| Comments | A negative resist process was done to make the mask. I have not had so good results with a positive resist process. | |
| Etch rate of TEOS oxide (5% load) | 233nm/min ±0.7% - "±" represents the non-uniformity over a 100mm wafer - etched in Marts 2013 by LN/BGE@danchip | |
| Etch rate of PECVD1 (standard) oxide (5% load) | 242nm/min ±0.6% - "±" represents the non-uniformity over a 100mm wafer - etched in Marts 2013 by LN/BGE@danchip | |
| Etch rate of Al2O from the ALD | 50nm can be etched in 10min - etched in November 2014 by FRSTO@danchip | |
| 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 SiO2 with DUV mask | See images here |
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 | . | . |