Specific Process Knowledge/Etch/Etching of Silicon Oxide/SiO2 etch using AOE/Standard recipe with resist mask/Striation: Difference between revisions
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=Striation: Side wall roughness= | =Striation: Side wall roughness= | ||
When etching silicon oxide rough sidewalls are most often seem. This effect is called striation, because it creates stripes along the etched profile. The litterature gives several coarses for this. The two main courses seems to be: # deposition on the sidewalls as the etch proceeds, coursing masking effects | When etching silicon oxide rough sidewalls are most often seem. This effect is called striation, because it creates stripes along the etched profile. The litterature gives several coarses for this. The two main courses seems to be: | ||
# deposition on the sidewalls as the etch proceeds, coursing masking effects | |||
# damage of the resist mask coursed by plasma heating and/or interaction with the resist. | # damage of the resist mask coursed by plasma heating and/or interaction with the resist. | ||
Revision as of 08:46, 20 April 2016
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Striation: Side wall roughness
When etching silicon oxide rough sidewalls are most often seem. This effect is called striation, because it creates stripes along the etched profile. The litterature gives several coarses for this. The two main courses seems to be:
- deposition on the sidewalls as the etch proceeds, coursing masking effects
- damage of the resist mask coursed by plasma heating and/or interaction with the resist.
This can be caused by polymer deposition which is a product of the process gasses. It can also be due to damage of the resist profile created during the etch this damage makes the resist edge rough and this pattern is transferred to the oxide profile. This effect is called striation, because it creates stripes along the etched profile. To avoid the polymer deposition one can chose to etch with
Sidewall roughness and resist surface after etch viewed with SEM
- Striation with different resists used
Az resist
Az resist
Az resist
Az resist - profile after etch
Mir resist
Mir resist
Mir resist
Mir resist - profile after etch
nLof
nLof
nLof
nLof resist - profile after etch
Roughness of the resist after etch measured with the AFM
AZ5214E:Ra=3.98nm, Rmax=33,0nm
AZ MIR: Ra=4.55nm, Rmax=36.3nm
AZ nLof 2020: Ra=3.31nm, Rmax=28.0nm
Sidewall roughness/resist surface roughness effected by UV curing and heat treatment of nLof resist 
| AOE etch with nLof resist with different treatments | |||||
| 1 | 2 | 3 | 4 | 5 | |
|---|---|---|---|---|---|
| Treatment | No treatment before AOE etch | No treatment after 5min AOE etch | Flood-E 70s + 1min@110dg | 5min@150dg | Flood-E 70s + 60s@110dg + 5min@150dg |
| SEM image | 
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| AFM roughness scan | Ra=2.1nm Rmax=25.1nm 
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Ra=3.31nm Rmax=28.0nm 
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Ra=3.34nm Rmax=26.8nm 
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Ra=2.45nm, Rmax=19.4nm 
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Ra=2.52nm, Rmax=23.7nm 
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| D | D1 | D2 | D3 | D4 | D5 |
Sidewall roughness/resist surface roughness effected by UV curing and heat treatment of AZ5214E resist
| AOE etch with AZ5214E resist with different treatments | |||||
| 1 | 2 | 3 | 4 | ||
|---|---|---|---|---|---|
| Treatment | No treatment before AOE etch | No treatment after 5min AOE etch | Flood-E 55s + 120s@110dg | Flood-E 55s + 120s@110dg + 5min@150dg | |
| SEM image | 
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| AFM roughness scan | Pre etch: cannot measure | Ra=4.40nm, Rmax=36.5nm 
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Ra=3.68nm, Rmax=25.6nm 
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Ra=3.57nm, Rmax=28.5nm 
| |
| D | D1 | D2 | D3 | D4 | |