Photoresist Strip SOP

Example of Photoresist on Surface of Chip

Photoresist Removed post-strip

Parameters

Total Time	1 minute
Acetone Spray Time	20 seconds
Isopropyl Alcohol Rinse Time	10 seconds
Nitrogen Blow Dry Time	10 seconds

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Purpose

Stripping removes all photoresist from a chip. This is typically done after an etch step is completed, though it can also be used to remove resist before etching if you need to redo patterning.

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Tools

1. Fume Hood with Sink

2. N2 gun

Materials

1. Chip with photoresist

2. Acetone

3. Isopropanol

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Troubleshooting and Best Practices

Chip flying out of tweezers during nitrogen blow drying

Lie the chip flat on a cleanroom wipe surface while still holding it with the tweezers.

Only apply nitrogen normal to the surface of the chip, so it presses against the cleanroom wipe instead of lifting it up.

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Procedure

Stripping

1. Spray the entire chip with acetone

2. Rinse with IPA

   1. IPA must always be used after acetone to remove any acetone residue

3. Dry with nitrogen gun until the surface is entirely dry

   1. This requires you to blow dry the back of the chip as well. Surface tension tends to pull the liquid towards the back

Safety

Be sure to spray the chip over a sink. Do not use near source of high heat.