Specific Process Knowledge/Etch/Etching of Silicon Oxide/SiO2 etch using ASE/tests CHF3+H2
Tests performed with UV resist:
The tests were performed on a 100mm wafer patterned on MLA3, with 2.2um AZ5214E resist.
| Recipe | Recipe parameters | Duration (min) | Date | SEM picture | Redeposition - top view | Profile angles | Etch rate in SiO2 | Etch rate in resist (AZ5214E inverse) |
Selectivity (SiO2:resist) |
|---|---|---|---|---|---|---|---|---|---|
| CHF3_t1 | CHF3= 22.5 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
12:00 | 04/09/2023 | 
|
|
69.7 nm/min +/- 10.5% |
57.3 nm/min +/- 12.9% |
1.22 | |
| CHF3_t2 | CHF3= 22.5 sccm Coil= 150W Platen= 25W Press= 2.5mTorr Temp= 20°C |
25:00 | 04/09/2023 | 
|
|
|
26.7 nm/min +/- 11.9% |
24.2 nm/min +/- 21.1% |
1.1 |
| CHF3 t2 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 25W Press= 2.5mTorr Temp= 20°C |
10:00 | 22/09/2023 | 
|
|
|
9,7 nm/min +/- 34.4% |
1,8 nm/min +/- 46.5% |
5.4 |
| CHF3_t1 | CHF3= 22.5 sccm H2= 10 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 12/09/2023 | 
|
|
|
59,6 nm/min +/- 12.9% |
47,5 nm/min +/- 21.5% |
1.25 |
| CHF3_t1 | CHF3= 22.5 sccm O2= 10 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 11/09/2023 | 
|
|
|
60,6 nm/min +/- 10.1% |
130,8 nm/min +/- 8.8% |
0.46 |
| CHF3 t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 20/09/2023 | 
|
|
|
47,3 nm/min +/- 12% |
26,4 nm/min +/- 17,4% |
1.8 |
| CHF3 t1 | CHF3= 22.5 sccm H2= 35 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 22/09/2023 | 
|
|
|
36,5 nm/min +/- 10.6% |
17,5 nm/min +/- 13.9% |
2.09 |
| CHF3 t1 | CHF3= 35 sccm H2= 35 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 22/09/2023 | 
|
|
|
42 nm/min +/- 15.4% |
23,8 nm/min +/- 22.2% |
1.76 |
| CHF3 t1 | CHF3= 22.5 sccm CF4= 22.5 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
10:00 | 22/09/2023 | 
|
|
|
75,8 nm/min +/- 13.1% |
74,9 nm/min +/- 10.8% |
1.01 |
| CHF3 t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 15W Press= 25mTorr Temp= 20°C |
10:00 | 22/09/2023 | 
|
|
|
- | - | no etch done, polymer deposited |
| CHF3 t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 0°C |
10:00 | 22/09/2023 | 
|
|
|
48 nm/min +/- 11.2% |
23,3 nm/min +/- 13.7% |
2.06 |
Tests performed with DUV resist:
The resist used was a negative DUV resist (UVN) with 915nm + 88nm BARC layer.
| Recipe | Recipe parameters | Duration (min) | Date | SEM picture | Etch rate in SiO2 | Etch rate in resist (UVN) |
Selectivity (SiO2:resist) |
|---|---|---|---|---|---|---|---|
| CHF3_t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 30W Press= 2.5mTorr Temp= 20°C |
10:00 | 13/11/23 |  
|
47 | 24.6 | 1.9 |
| CHF3_t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 45W Press= 2.5mTorr Temp= 20°C |
10:00 | 13/11/23 |  
|
59 | 30 | 1.9 |
| CHF3_t1 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 45W Press= 2.5mTorr Temp= 0°C |
10:00 | 07/12/23 | 
|
96 | 56 | 1.7 |
| CHF3_t2 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 25W Press= 2.5mTorr Temp= 20°C |
10:00 | 23/10/23 | 
|
27 | 12,5 | 2.1 |
| CHF3_t2 | CHF3= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 25W Press= 2.5mTorr Temp= 20°C |
20:00 | 23/10/23 | 
|
8.15 | 7.5 | 1.1 |
SiO2 test - 5 jan 2024
- The SiO2 layer deposited was 2um, deposited on the C1 furnace (recipe: WET1100, 12h40+00:20).
- They were patterned with 915 UVN resist (DUV negative) and 65nm of BARC.
- The following results were processed on chips (2*2cm) bonded to a 100mm dummy wafer.
| Recipe | Time (min) | Date | SEM picture | Etch rate SiO2 (nm/min) | Etch rate resist (nm/min) | Selectivity (SiO2:resist) |
|---|---|---|---|---|---|---|
| CHF3_t1 CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 30W Press= 2.5mTorr Temp= 20°C |
10:00 | 25/01 -2024 |
   
|
250nm- 61,99 500nm- 68,12 1000nm- 74,7 2000nm- 76,55 |
250nm- 61,31 500nm- 49,85 1000nm- 46,83 2000nm- 47,3 |
250nm- 1,01 500nm- 1,37 1000nm- 1,6 2000nm- 1,62 |
| CHF3_t1 CHF3= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 45W Press= 2.5mTorr Temp= 20°C |
10:00 | 25/01 -2024 |
   
|
250nm- 90,74 500nm- 84,63 1000nm- 89,33 2000nm- 94,34 |
250nm- 81,1 500nm- 53,77 1000nm- 52,23 2000nm- 54,81 |
250nm- 1,12 500nm- 1,57 1000nm- 1,71 2000nm- 1,72 |
| CHF3_t2 CF4= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 45W Press= 2.5mTorr Temp= 20°C |
15:00 | 25/01 -2024 |
    *it's visible that redeposits, so the ER and selectivity may not be correct. |
250nm- 9,18 500nm- 22,46 1000nm- 28,03 2000nm- 28,75 |
250nm- 11,09 500nm- 3,96 1000nm- 4,22 2000nm- 4,40 |
250nm- 0,83 500nm- 5,67 1000nm- 6,64 2000nm- 6,5 |
Etch test of Silicon Nitride
- The nitride layer deposited was 560nm, on the PECVD4 (recipe: Standard HF SiN with wafer clean, for 1h).
- They were patterned with 750 DUV resist and 65nm of BARC (exposure:355 J/m2, focus:-3.1).
- The following results were processed on chips (2*2cm) bonded to a 100mm dummy wafer.
| Recipe | Time (min) | Date | SEM picture | Redeposition - top view | Etch rate SiN (nm/min) | Etch rate resist (nm/min) | Selectivity (SiN:resist) |
|---|---|---|---|---|---|---|---|
| CHF3_t1 CHF3= 22.5 sccm H2= 22.5 sccm Coil= 800W Platen= 15W Press= 2.5mTorr Temp= 20°C |
2:30 | 29/02 -2024 |
   
|
 
|
250nm- 155,08 500nm- 170,32 1000nm- 174,45 2000nm- 179,76 |
250nm- 65,52 500nm- 56,36 1000nm- 64,56 2000nm- 68,84 |
250nm- 2,37 500nm- 3,02 1000nm- 2,70 2000nm- 2,61 |
| CHF3_t2 CHF3= 22.5 sccm H2= 22.5 sccm Coil= 150W Platen= 45W Press= 2.5mTorr Temp= 20°C |
5:00 | 29/02 -2024 |
   
|
 
|
250nm- 28,12 500nm- 41,86 1000nm- 66 2000nm- 63,62 |
250nm- 23,26 500nm- 22,60 1000nm- 16,74 2000nm- 15,34 |
250nm- 1.21 500nm- 1.85 1000nm- 3.94 2000nm- 4.15 |