Specific Process Knowledge/Wafer cleaning/RCA: Difference between revisions
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! HF | ! HF | ||
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|'''General description''' | |'''General description''' | ||
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Used for removal of oxide generated in RCA1 and RCA2 | Used for removal of oxide generated in RCA1 and RCA2 | ||
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|'''Chemical solution''' | |'''Chemical solution''' | ||
|H<sub>2</sub>O, NH<sub>4</sub>OH(25-29%) and H<sub>2</sub>O<sub>2</sub>(30%) (5:1:1) | |H<sub>2</sub>O, NH<sub>4</sub>OH(25-29%) and H<sub>2</sub>O<sub>2</sub>(30%) (5:1:1) | ||
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|5% HF | |5% HF | ||
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|'''Process temperature''' | |'''Process temperature''' | ||
|70-80 <sup>o</sup>C | |70-80 <sup>o</sup>C | ||
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|Room temperature | |Room temperature | ||
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|'''Process time''' | |'''Process time''' | ||
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30 sec. | 30 sec. | ||
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|'''Life time of the chemical solutions''' | |'''Life time of the chemical solutions''' | ||
|Can only be heated one time. When hot: it lasts for ~1h | |Can only be heated one time. When hot: it lasts for ~1h | ||
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|~2 months | |~2 months | ||
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|'''Allowed materials''' | |'''Allowed materials''' | ||
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*Silicon nitride | *Silicon nitride | ||
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|'''Batch size''' | |'''Batch size''' | ||
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1-25 2",4" or 6" wafers at a time | 1-25 2",4" or 6" wafers at a time | ||
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|'''Size of substrate''' | |'''Size of substrate''' | ||
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Revision as of 11:43, 3 March 2014
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RCA cleaning
RCA1 - RCA2 - HF - BHF(pre-dep wafers)
The RCA clean is used for cleaning the wafers before taking them into the furnaces and a few other equipments (check the cross contamination sheet). It consists of two solutions: RCA1 and RCA2 plus diluted HF. A crucial part of the RCA clean is the oxidation by H2O2. Therefore the life time of the RCA solutions are limited by the presence of the H2O2 which is highly volatile at 70 oC.
- The RCA1 contains: H2O, NH4OH and H2O2 (5:1:1). It is used for removal of light organics, particles and metals.
- The RCA2 contains: H2O, HCl and H2O2 (5:1:1). It is used for removal of alkalis, metal hydroxides, and residual metals.
You can find the APV here
RCA procedure
- RCA1: 10 min
- DI water rinsing (dumping three times)
- HF: 30 sec (you may avoid this step in case of a very thin oxide (0-200 Å) as the top layer)
- DI water rinsing (dumping three times)
- RCA2: 10 min
- DI water rinsing (dumping three times)
- Optional: HF: 30 sec (avoid it if you have a very thin oxide (0-200 Å) as the top layer)
- DI water rinsing (dumping three times)
For procedure details please look in the user manual in LabManager.
The user manual, user APV and contact information can be found in LabManager: RCA info page in LabManager
Overview of RCA process data
| RCA1 | RCA2 | HF | |
|---|---|---|---|
| General description |
Used for removal of light organics, particles and desorption of trace metals (Au, Ag, Ni, Cd, Zn, Co, Cr, etc). |
Used for removal of alkali ions, metal hydroxides (of Al, Fe, Mg, Zn) and residual trace metals (e.g. Cu and Au). |
Used for removal of oxide generated in RCA1 and RCA2 |
| Chemical solution | H2O, NH4OH(25-29%) and H2O2(30%) (5:1:1) | H2O, HCl(37%) and H2O2(30%) (5:1:1) | 5% HF |
| Process temperature | 70-80 oC | 70-80 oC | Room temperature |
| Process time |
10 min. |
10 min. |
30 sec. |
| Life time of the chemical solutions | Can only be heated one time. When hot: it lasts for ~1h | Can only be heated one time. When hot: it lasts for ~1h | ~2 months |
| Allowed materials |
|
|
|
| Batch size |
1-25 2",4" or 6" wafers at a time |
1-25 2",4" or 6" wafers at a time |
1-25 2",4" or 6" wafers at a time |
| Size of substrate |
4"-6" wafers |
4"-6" wafers |
4"-6" wafers |