Specific Process Knowledge/Lithography/Pretreatment: Difference between revisions
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'''Feedback to this page''': '''[mailto:photolith@ | '''Feedback to this page''': '''[mailto:photolith@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Pretreatment click here]''' | ||
=Pretreatment= | =Pretreatment= | ||
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=HMDS= | =HMDS= | ||
'''Feedback to this section''': '''[mailto:photolith@ | '''Feedback to this section''': '''[mailto:photolith@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Pretreatment#HMDS click here]''' | ||
The chemical treatment with hexamethyldisilazane (HMDS) before the spin coating can be used to promote the adhesion for photoresist. Vapor priming with HMDS leaves a mono-layer of TMS (trimethylsilyl) on the Si or SiO<sub>2</sub> surface. The process dehydrates the substrate surface, and lowers the surface tension. | The chemical treatment with hexamethyldisilazane (HMDS) before the spin coating can be used to promote the adhesion for photoresist. Vapor priming with HMDS leaves a mono-layer of TMS (trimethylsilyl) on the Si or SiO<sub>2</sub> surface. The process dehydrates the substrate surface, and lowers the surface tension. | ||
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'''The user manual, user APV, and contact information can be found in LabManager:''' | '''The user manual, user APV, and contact information can be found in LabManager:''' | ||
[http://labmanager | [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=54 HMDS oven in LabManager] | ||
===Process information=== | ===Process information=== | ||
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'''Additional information about the spin track and processes can be found in Labadviser:''' | '''Additional information about the spin track and processes can be found in Labadviser:''' | ||
[http://labadviser | [http://labadviser.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Coaters#Spin_Track_1_.2B_2 Spin track 1 + 2 labadviser page] | ||
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'''Additional information about the spin coater and processes can be found in Labadviser:''' | '''Additional information about the spin coater and processes can be found in Labadviser:''' | ||
[http://labadviser | [http://labadviser.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Coaters#gamma_uv Spincoater: Gamma UV labadviser page] | ||
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=Buffered HF-Clean= | =Buffered HF-Clean= | ||
'''Feedback to this section''': '''[mailto:labadviser@ | '''Feedback to this section''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Pretreatment#Buffered_HF-Clean click here]''' | ||
[[Image:BHF_RR3.jpg|300x300px|thumb|Buffered HF-Clean in C-1]] | [[Image:BHF_RR3.jpg|300x300px|thumb|Buffered HF-Clean in C-1]] | ||
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'''The user manual, user APV, and contact information can be found in LabManager:''' | '''The user manual, user APV, and contact information can be found in LabManager:''' | ||
[http://labmanager. | [http://labmanager.nanolab.dtu.dk/function.php?module=Machine&view=view&mach=64 Buffered HF-Clean in LabManager] | ||
===Process information=== | ===Process information=== | ||
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=Oven 250C= | =Oven 250C= | ||
'''Feedback to this section''': '''[mailto:labadviser@ | '''Feedback to this section''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Lithography/Pretreatment#Oven_250C click here]''' | ||
[[Image:Oven_250_degrees_for_pretreatment_cr3.jpg|300x300px|thumb|Oven 250C for pretreatment in C-1]] | [[Image:Oven_250_degrees_for_pretreatment_cr3.jpg|300x300px|thumb|Oven 250C for pretreatment in C-1]] | ||
The oven is typically used for pretreatment (dehydration) of Si and glass substrates to promote the resist adhesion. We recommend to place the wafers in metal carrier in the oven at least for 4 hours, better during the night, and spin the resist on them asap. | The oven is typically used for pretreatment (dehydration) of Si and glass substrates to promote the resist adhesion. We recommend to place the wafers in metal carrier in the oven at least for 4 hours, better during the night, and spin the resist on them asap. | ||
'''The user manual, and contact information can be found in LabManager: [http://labmanager | '''The user manual, and contact information can be found in LabManager: [http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=117 Oven 250C]''' | ||
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Revision as of 17:37, 25 November 2019
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Pretreatment
All surfaces can be divided to hydrophilic or hydrophobic surfaces. Oxidized surfaces such as SiO2 or surfaces with native oxide (e.g. Si or Al substrates) are considered to be hydrophilic and have very bad wetting with hydrophobic resist. The adhesion of most resists on hydrophilic surfaces is deteriorated if moisture is present on the surface.
Therefore it is very important to do the pretreatment step before the spinning. Here we will give an overview of treatments available at Danchip to promote photoresist adhesion.
Comparing pretreatment methods
HMDS | Buffered HF-Clean | Oven 250C | |
---|---|---|---|
Generel description |
Vapor priming |
Native oxide strip |
Dehydration |
Chemical |
hexamethyldisilazane (HMDS) |
12%HF with Ammoniumflouride |
none |
Substrate size |
|
|
|
Allowed materials |
Silicon, glass, and polymer substrates Film or pattern of all but types, except type IV and resist/polymer |
|
|
Restrictions | Type IV and resist/polymer on polymer substrate | Wafers with metal is not allowed | Resist is not allowed |
HMDS
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The chemical treatment with hexamethyldisilazane (HMDS) before the spin coating can be used to promote the adhesion for photoresist. Vapor priming with HMDS leaves a mono-layer of TMS (trimethylsilyl) on the Si or SiO2 surface. The process dehydrates the substrate surface, and lowers the surface tension.
The molecular formula for hexamethyldisilazane, or bis(trimethylsilyl)amine, is C6H19NSi2. Here is a schematic overview of HMDS treatment of silicon-oxide surface.
Comparing HMDS priming
Equipment | HMDS oven | Oven: HMDS 2 | Spin Track 1 + 2 | Gamma UV | |
---|---|---|---|---|---|
Purpose |
|
|
|
| |
Priming chemical |
hexamethyldisilizane (HMDS) | ||||
Performance | Contact angle |
|
|
Track 1 [Track 2]:
|
Fast recipe [standard recipe]:
|
Process parameters | Process temperature |
150°C |
150°C |
50°C |
120°C |
Process time |
32.5 minutes |
25 minutes |
3 min / wafer |
1 min / wafer | |
Substrates | Substrate size |
|
|
|
|
Allowed materials |
Silicon, glass, and polymer substrates III-V materials on silicon carrier Film or pattern of all but types, except type IV and resist/polymer |
Silicon, glass, and polymer substrates III-V materials on silicon carrier Film or pattern of all but types, except type IV and resist/polymer |
Silicon and glass wafers Film or pattern of all types |
Silicon and glass wafers Film or pattern of all but types, except type IV and resist/polymer | |
Batch |
1 - 25, multiple batches possible |
1 - 25, multiple batches possible |
1 - 25 |
1 - 25 |
HMDS oven
At Danchip we use Star2000 model from IMTEC to do vapor deposition of hexamethyldisilizane (HMDS) under the special conditions: low pressure and high chamber temperature. The result of the dehydration bake and HMDS prime is that the wafers become hydrophobic after the treatment.
The user manual, user APV, and contact information can be found in LabManager:
Process information
- Recipe 4: baseline prime process with 5 min priming time
Baseline prime process description:
1. Pump-down, 2 min
2. Nitrogen purge, 3.5 min
3. Heat-up, 10 min
4. Pump-down to 3 mBar
5. HMDS prime, 5 min
6. Chamber exhaust, 3 min
7. Nitrogen purge, 3.5 min
Oven: HMDS 2
The user manual, user APV, and contact information can be found in LabManager:
Process information
- Recipe 1: baseline prime process with 5 min HMDS priming time
Spin track 1 + 2
The user manual, user APV, and contact information can be found in LabManager:
Spin track 1 + 2 labmanager page
Additional information about the spin track and processes can be found in Labadviser:
Spin track 1 + 2 labadviser page
Spincoater: gamma UV
The user manual, user APV, and contact information can be found in LabManager:
Spincoater: Gamma UV labmanager page
Additional information about the spin coater and processes can be found in Labadviser:
Spincoater: Gamma UV labadviser page
Buffered HF-Clean
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Another commonly used method to render the surface of silicon wafers hydrophobic is the dilute HF dip.
BHF is mostly used to do pretreatment step for new Si wafers. The native dioxide layer will be removed during 30 sec etching and in this way we will promote the resist adhesion on the Si substrates. We recommend to spin resist asap after the procedure.
The user manual, user APV, and contact information can be found in LabManager:
Buffered HF-Clean in LabManager
Process information
For more information on this BHF bath take a look here: Wet Silicon Oxide Etch (BHF)
Oven 250C
Feedback to this section: click here
The oven is typically used for pretreatment (dehydration) of Si and glass substrates to promote the resist adhesion. We recommend to place the wafers in metal carrier in the oven at least for 4 hours, better during the night, and spin the resist on them asap.
The user manual, and contact information can be found in LabManager: Oven 250C