Difference between revisions of "Soft Lithography"

From Quattrone Nanofabrication Facility
Jump to navigation Jump to search
(Created page with "Category:Lithography Category:Soft Lithography '''THIS PAGE IS UNDER CONSTRUCTION''' * [https://wiki.nano.upenn.edu/wiki/images/c/cf/Microfluidics_Process_Flow.pdf Pr...")
 
 
(16 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
[[Category:Lithography]] [[Category:Soft Lithography]]
 
[[Category:Lithography]] [[Category:Soft Lithography]]
 +
__NOTOC__
 +
===About===
 +
Soft lithography is the transfer of patterned microstructures with molded elastomer. The most common elastomer used in this technique is PDMS (polydimethylsiloxane), which is <u>soft</u>, low cost and easy to mold. It is also bio-compatible with high thermal stability and high chemical stability, is chemically inert, insulating, transparent to UV and visible light, mechanically flexible and durable, allowing many applications. The most common devices fabricated with this technique are microfluidics. <br>
 +
<u><small>'''NOTE</u>:'''</small> You might hear soft lithography equated to "microfluidics fabrication." However, it is important to remember that not all microfluidic devices are fabricated by soft lithography and not all soft lithography is for microfluidic applications!
  
−
'''THIS PAGE IS UNDER CONSTRUCTION'''
+
===Process Flow===
−
* [https://wiki.nano.upenn.edu/wiki/images/c/cf/Microfluidics_Process_Flow.pdf Process Flow]
+
*The master used can be fabricated out of photoresist or etched silicon. The most commonly used materials are epoxy-based negative photoresist (SU8 or HARE SQ). For a negative photoresist, the parts exposed to UV become cross-linked, while the remainder of the film remains soluble and can be washed away during development. The height of this structure is determined by the thickness of the resist, which we control through our application method. The length and width of features are patterned through the UV exposure, either by mask or direct write tools.<br>
−
* [https://upenn.box.com/s/b6e694cf6r5qul32cmsjkbr9oydc6d7o Course Material for the QNF Soft Lithography Workshop]
+
*For molding success, there are two important components to think about -- master durability and PDMS removal. Etched silicon molds will be more durable than patterned photoresist. However, an O2 plasma treatment under vacuum before applying resist has shown more than sufficient adhesion for patterned HARE SQ in our own tests. To enable easy release of the PDMS from the mold, it can be beneficial to do a silanization treatment before applying the PDMS.<br>
−
* [https://upenn.box.com/s/xrlkb6agcqae7ietb16mk5d84zqbcbr0 PDF Presentation for Biological Researchers]
+
*An O2 plasma step is included if applying the PDMS to glass or another piece of PDMS to make a device.
−
* [https://upenn.box.com/s/10wkjldwrt3f6it5ted0jo74b72eu0m4 PDF Presentation for ESE 536]
 
−
* Training Videos
 
−
:* [https://www.youtube.com/watch?v=ybFHtd2pPYs Training Video - Spin Coating Thick Resist]
 
−
:* [https://www.youtube.com/watch?v=cRzLljt0VLs Training Video - Use of MA-03, ABM Mask Aligner]
 
−
:* [https://www.youtube.com/watch?v=SCs87pYIn5w Training Video - Negative Resist First Mask Alignment Mark]
 
−
:* [https://www.youtube.com/watch?v=Wzrsv_01ZNE Training Video - Developing SU8 Resist]
 
−
:* [https://www.youtube.com/watch?v=powcV3r4IhM Training Video - Degassing PDMS]
 
  
 +
=====QNF Example Protocols=====
 +
* [https://wiki.nano.upenn.edu/wiki/images/c/cf/Microfluidics_Process_Flow.pdf Making a Master: HARE SQ, MA-03]
 +
* Making a Device: PDMS to PDMS bonding
 +
<pdf height="500" width="1100"> File:SOP Microfluidics.pdf</pdf>
  
 +
=====Videos=====
 +
* [https://www.youtube.com/watch?v=ybFHtd2pPYs Spin Coating Thick Resist]
 +
* [https://www.youtube.com/watch?v=SCs87pYIn5w Negative Resist First Mask Alignment Mark]
 +
* [https://www.youtube.com/watch?v=Wzrsv_01ZNE Developing SU8 Resist]
 +
* [https://www.youtube.com/watch?v=powcV3r4IhM Degassing PDMS]
 +
 +
===Equipment at QNF===
 +
===== Soft Materials =====
 +
* '''DE-07:''' [[Anatech SCE-106 Barrel Asher | Anatech SCE-106 Barrel Asher]]
 +
* '''MA-03:''' [[ABM Mask Aligner | ABM Mask Aligner]]
 +
* '''PVD-08:''' Silanization Dessicator
 +
* '''SPN-08:''' [[ CEE Apogee Spinner | CEE Apogee Spinner - Negative Epoxy]]
 +
* '''SPN-09:''' [[ CEE Apogee Spinner | CEE Apogee Spinner - PDMS]]
 +
* '''LW-02:''' [[Nanoscribe Photonic Professional GT | Nanoscribe Photonic Professional GT]]
 +
===== Main Cleanroom =====
 +
* '''LW-01:''' [[Heidelberg DWL 66+ Laser Writer | Heidelberg DWL 66+ Laser Writer]]
 +
* '''LW-03:''' [[DMO MicroWriter ML3 Pro | DMO MicroWriter ML3 Pro ]]
 +
* '''MA-01:''' [[SUSS MicroTec MA6 Gen3 Mask Aligner | SUSS MicroTec MA6 Gen3 Mask Aligner]]
 +
* '''DE-03:''' [[SPTS Si DRIE | SPTS Si DRIE]] 
 +
 +
===Additional Information===
 +
=====Related Wiki Pages=====
 +
* [[Photolithography]]
 +
* [[Resists at QNF]]
 
* [[How to Make a Mask]]
 
* [[How to Make a Mask]]
−
* [[Resists at QNF]]
 
  
−
=====Resources=====
+
=====Internal Reports & Presentations=====
 +
*[https://repository.upenn.edu/entities/publication/ae5bbb10-7b45-4568-9f0f-f2f27e7d95c2 T-Topping Study Report]
 +
*HARE SQ Adhesion Study ''- coming soon''
 +
* [https://upenn.box.com/s/b6e694cf6r5qul32cmsjkbr9oydc6d7o QNF Soft Lithography Workshop Process Flow - SU8 3050]
 +
* [https://upenn.box.com/s/xrlkb6agcqae7ietb16mk5d84zqbcbr0 Presentation for Workshop - Biological Researchers (PDF Format)]
 +
* [https://upenn.box.com/s/10wkjldwrt3f6it5ted0jo74b72eu0m4 Presentation for ESE 536 Course Module (PDF Format)]
 +
=====External Resources=====
 +
*[https://df393c79-ecb8-453c-bf20-359d99bdbc77.filesusr.com/ugd/5b8579_bc178fb3a8fb47828522de434712b455.pdf HARE SQ Dispensing and Handling Techniques - KemLab]
 +
*[https://piescientific.com/resource-pdms-bonding/ PDMS Bonding - PIE Scientific]
 +
*Microfluidics and Nanofluidics Handbook: SU-8 Photolithography and Its Impact on Microfluidics by Rodrigo Martinez-Duarte and Marc J. Madou

Latest revision as of 15:25, 26 August 2025


About

Soft lithography is the transfer of patterned microstructures with molded elastomer. The most common elastomer used in this technique is PDMS (polydimethylsiloxane), which is soft, low cost and easy to mold. It is also bio-compatible with high thermal stability and high chemical stability, is chemically inert, insulating, transparent to UV and visible light, mechanically flexible and durable, allowing many applications. The most common devices fabricated with this technique are microfluidics.
NOTE: You might hear soft lithography equated to "microfluidics fabrication." However, it is important to remember that not all microfluidic devices are fabricated by soft lithography and not all soft lithography is for microfluidic applications!

Process Flow

  • The master used can be fabricated out of photoresist or etched silicon. The most commonly used materials are epoxy-based negative photoresist (SU8 or HARE SQ). For a negative photoresist, the parts exposed to UV become cross-linked, while the remainder of the film remains soluble and can be washed away during development. The height of this structure is determined by the thickness of the resist, which we control through our application method. The length and width of features are patterned through the UV exposure, either by mask or direct write tools.
  • For molding success, there are two important components to think about -- master durability and PDMS removal. Etched silicon molds will be more durable than patterned photoresist. However, an O2 plasma treatment under vacuum before applying resist has shown more than sufficient adhesion for patterned HARE SQ in our own tests. To enable easy release of the PDMS from the mold, it can be beneficial to do a silanization treatment before applying the PDMS.
  • An O2 plasma step is included if applying the PDMS to glass or another piece of PDMS to make a device.
QNF Example Protocols

Videos

Equipment at QNF

Soft Materials
Main Cleanroom

Additional Information

Related Wiki Pages
Internal Reports & Presentations
External Resources
Retrieved from "https://wiki.nano.upenn.edu/wiki/index.php?title=Soft_Lithography&oldid=2896"