Photoresist

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.

Contents

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.