Specific Process Knowledge/Etch/Etching of Bulk Glass/AOE etching of fused silica: Difference between revisions
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!Etch rate in fused silica | !Etch rate in fused silica | ||
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*193.2±0.4nm/min @5min etch (2013-03-26) | *193.2±0.4nm/min @5min etch (2013-03-26)(50nm Al on back side) | ||
*173.5±0.5nm/min @40min etch (2013-03-13) | *173.5±0.5nm/min @40min etch (2013-03-13) (100nm Al on back side) | ||
*208nm/min @(5+5)min (2013-08-27) (no Al on back side, He pressure 6.8T) | |||
Reduced etch rate in long etch might be due to either resist gone at the end, substrate being very hot=>larger polymerization during etch. The polymer/resist left on the wafer after etch was less than 20nm and it looked burned. | Reduced etch rate in long etch might be due to either resist gone at the end, substrate being very hot=>larger polymerization during etch. The polymer/resist left on the wafer after etch was less than 20nm and it looked burned. | ||
± refers to the variation over the wafer. | ± refers to the variation over the wafer. |
Revision as of 10:41, 27 August 2013
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Comparison of masking materials and AOE processes etching fused silica
AZ resist mask | PolySi mask | |
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Generel description | Using a photoresist mask as etching mask is often convenient, since it takes less process steps to make than hard masks. The draw backs using resist as masking material in the AOE on glass is that glass does not transfer heat well and therefore the He cooling in the AOE does not work well on glass substrates. This makes the photoresist turn very hot during the etch and that might burn the resist. Resist also has low selectivity to glass so deep glass etch is not working well with photoresist as masking material. | Using Poly Silicon as masking material in the AOE has the advantage over photoresist in the fact that the mask can stand a higher temperature. Then a recipe with higher etch can be used. It also as a higher selectivity so it is possible to etch deeper.The draw back might be higher line width reduction but this has not been expored yet. |
Mask material/thickness |
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Coil Power |
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Platen Power |
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Platen temperature |
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He flow |
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C4F8 flow |
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H2 flow |
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Pressure |
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Etch rate in fused silica |
Reduced etch rate in long etch might be due to either resist gone at the end, substrate being very hot=>larger polymerization during etch. The polymer/resist left on the wafer after etch was less than 20nm and it looked burned. ± refers to the variation over the wafer. |
± refers to the variation over the wafer. |
Selectivity to mask |
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Substrate size tried |
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