Photoresist

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Photoresist is a photoactive polymer suspended in a solvent used in Lithography processing. We have positive novolak based resists for use with our mask aligners and stepper, negative epoxy based resists ..... and e-beam resists for use with the JOEL.


LNF Supported Photoresists

Name LNF stock Positive/Negative Reversible Min Thickness (um) Max Thickness (um) Exposure type RIE Wet Etching Plating Lift-off Comments
[SPR 955 (0.9)] Y Pos Y 0.97 0.97 UV Good OK Good OK Considered a high resolution resist. The material underneath the resist has a significant impact on the required dose
[SPR 220 (3.0)] Y Pos Y 2 5 UV Good OK Good OK Not recommended for long wet etches (specially after exposure to plasma)
SPR 220 7.0 N Pos Y 6 12 UV Good OK Bad OK
AZ 12XT N Pos N 10 25 UV Good Good OK OK This is a chemically enhanced PR.
AZ 5214E N Pos Y 1 2 UV OK OK Bad Good Image Reversal Resist for High Resolution and intended for lift-off
Shipley 1813 Y Pos Y 1 1.3 UV OK Good Bad Good It must be hard baked for wet etches. It is thin and not good for long wet etches.
PMGI SF 6 N N/A N/A 0.28 0.68 N/A Bad Bad Bad Good This is an LOR resist. The thickness should be at least 1.5x the thickness or metal. Other LOR versions are available for different thicknesses.
LOR 10B N N/A N/A 0.9 1.8 N/A Bad Bad Bad Good LOR thickness should be at least 1.5x the thickness or metal. Other LOR versions are available for different thicknesses.
KMPR 1010 N Neg N 10 20 UV Good Good OK Bad Resist can swell during metal coating.
[KMPR 1025] N Neg N 20 70 UV Good Good OK Bad Resist can swell during metal coating.
SU-8 2005 N Neg N 4 7 UV Good Good OK Bad This resist is considered a thick chemically and thermally stable epoxy. Coating only allow in Wet Chemistry. Extremely hard to remove.
SU-8 2010 N Neg N 10 20 UV Good Good OK Bad This resist is considered a thick chemically and thermally stable epoxy. Coating only allow in Wet Chemistry. Extremely hard to remove.
SU-8 2050 N Neg N 40 170 UV Good Good OK Bad This resist is considered a thick chemically and thermally stable epoxy. Coating only allow in Wet Chemistry. Extremely hard to remove.
PMMA 950 A2 Y Pos N 0.05 0.10 E-beam OK OK Good Good It is use for direct writing on the e-beam
[PMMA 950 A4] Y Pos N 0.20 0.40 E-beam OK OK Good Good It is use for direct writing on the e-beam
[PMMA 950 A9] Y Pos N 1.5 2.8 E-beam OK OK Good Good It is use for direct writing on the e-beam
[PMMA 495 A2] Y Pos N 0.05 0.10 E-beam Bad OK Good Good It is use for direct writing on the e-beam
[PMMA 495 A4] Y Pos N 0.18 0.30 E-beam Bad OK Good Good It is use for direct writing on the e-beam
ZEP 520A N Pos N E-beam Good Bad It is use for direct writing on the e-beam


LNF stock: This parameter indicates if the resist is supplied by LNF.

Positive/Negative: Positive resist develop the exposed areas, negative resists develope unexposed areas.

Reversible: Some photoresist allowed to have the polarity reverse.

Applications

Etch

  • RIE - Photoresist used in RIE needs to be thermally stable and resistant to the etch chemistry.
  • Wet Etch - A photoresists adhesion is very important as any adhesion failure greatly increases undercut.

Deposition

  • Liftoff - Need a photoresist profile that prevents sidewall deposition. Often this is done by using a bi-layer stack and undercutting the bottom layer.
  • Plating
  • Molding


Below you can find a list of public and private approved photoresists for the LNF. If you would like to bring a new photoresist into the robin lab or clean room, then please create a help desk ticket or email info@lnf.umich.edu. All photoresists must be handled using the green polychloroprene gloves.