AZ 4620 process


INRF application note

Process Name:

AZ4620 Resist Photolithography (12 μm)


Qingzhou Xu and Liang (Lily) Wu, Spring 2002.  Adapted for AMPEL ANF, M. Beaudoin, April 2014.

The process described here is to deposit thick (12 μm) AZ4620 resist, which can be used as electroplating molds, with good resolution and reproducibility. The patterning of AZ4620 photoresist is performed by using a mask and an UV light contact aligner. This is a level-2 process; it requires superuser instruction.
Time Needed:

The spin steps take approximately 20 minutes. The lithography (exposure and develop) take approximately 10-15 minutes. The entire process needs approximately half an hour.

Materials Needed:
  • AZ4620 photoresist
  • Mask
  • Developer solution
  • Glass container

Make developer solution of 1 part AZ400K and 3 parts DI water (by volume).


Place substrate on spinner chuck. Pour a puddle of AZ4620 on the center of the substrate to be coated.

Spin on thick AZ4620 photoresist coatings on substrate by a one-step spin process at 2000 rpm for 40 seconds with an acceleration of 425rpm/s to achieve approximately a thickness of 12 μm. Bake the resist coatings at 90oC in an oven for 12 minutes.

Expose AZ4620 photoresist coatings for 1.5 minutes using the Karl Suss aligner.

Develop AZ4620 photoresist coatings for approximately 1.5 minutes. It is important to keep watching in order to avoid over-developing. Rinse the substrate completely with DI water followed by blow drying.

Post-bake at 90oC for 20 minutes is optional. It is not recommended for thick films since it causes distortion of the patterns due to reflow.

Inspect the patterned wafer to ensure that there is no residue and that all features have patterned properly.


Dispose the developer waste in a labeled container. Rinse all glassware with DI water. Spray the interior of the spinner with acetone. Wipe down the spinner with lint-free wipes, paying attention to the lid and the chuck.

Safety & Emergency:

All ANF safety and procedural regulations must be followed. Review the ANF standard operating procedures for fire, chemical spill, and chemical exposure. Photoresist and acetone are flammable chemicals. Do not store the photoresist or acetone near the hotplate or any other source of heat. Any small spills should be wiped up immediately with wipes. Dispose the wipes in the flammable waste container.

In case of exposure to skin or eyes, flush immediately with water for 15 minutes. Remove all clothing that are exposed and flush with water. Report to ANF staff or report to UBC Risk Management. Seek medical attention to ensure that the burns are minimal. In case of large spill, follow the ANF Standard Operating Procedure for chemical spills.