Specific Process Knowledge/Etch/Etching of Silicon Oxide/SiO2 etch using ASE/More test with CF4/H2, CHF3 and C4F8/H2 - SiO2 etch: Difference between revisions
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===Recent results - <span style="background:#FFD850">CF<sub>4</sub> / H<sub>2</sub> tests</span> === | ===Recent results - <span style="background:#FFD850">CF<sub>4</sub> / H<sub>2</sub> tests</span> === | ||
The following results were processed on chips bonded to a 100mm wafer. They were patterned with 915 UVN resist (DUV negative) and 65nm of BARC. The SiO2 layer was 2um (deposited on the C1 furnace). | The following results were processed on chips bonded to a 100mm wafer. They were patterned with 915 UVN resist (DUV negative) and 65nm of BARC. The SiO2 layer was 2um (deposited on the C1 furnace). <br> | ||
(25 jan 2024) | (25 jan 2024) | ||
Revision as of 14:06, 22 April 2024
More test with CF4/H2 - SiO2 etch
Tests performed by Maria Farinha @DTU Nanolab
The gas flows were combined and the following results were achieved. It´s visible that with higher CF4 the selectivity is not good, so by adding H2, until 1:1, the selectivity improves. Additionally, the uniformity gets slightly worse while going for 1:1 of gas chemistry.
The recipe CF4lowCP 22.5/22.5 seems to be the only one good enough to use. It is a slow etch recipe, with good selectivity with AZ5214E resist.
CF4ICP | SiO2 ER (nm/min) | Uniformity (SiO2 etch) | Selectivity (SiO2:resist) | Si3N4 ER (nm/min) | SixN ER (nm/min) |
---|---|---|---|---|---|
45 CF4 + 0 H2 | |||||
35 CF4 + 10 H2 | |||||
22.5 CF4 + 22.5 H2 |
- The uniformity considers a 100mm wafer, calculated with 5 points.
CF4lowCP | SiO2 ER (nm/min) | Uniformity (SiO2 etch) | Selectivity (SiO2:resist) | Si3N4 ER (nm/min) | SixN ER (nm/min) |
---|---|---|---|---|---|
45 CF4 + 0 H2 | |||||
35 CF4 + 10 H2 | |||||
22.5 CF4 + 22.5 H2 |
Profile pictures of some tests - April 2023
Even in the cases with the resist strip (plasma asher 2 processing for 10/15min), there are some traces of resist left on the edges of the features.
Also, it´s noticeable that the feature profile is trenching, being more evident with faster etch rates.
Recipes and results - CF4 / H2 tests
Recent results - CF4 / H2 tests
The following results were processed on chips bonded to a 100mm wafer. They were patterned with 915 UVN resist (DUV negative) and 65nm of BARC. The SiO2 layer was 2um (deposited on the C1 furnace).
(25 jan 2024)