Lift-off resist

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About this Process
LORpic.png
Process Details
Equipment Lift-off resist
Technology Lithography


LOR or lift off resist process is a method of getting better definition of structures while using liftoff. By using 2 layers of material you are able to create a negative profile and are able to get better definition of the features. You can purchase tubes of LOR 10B through the LNF store.

Procedure

You can purchase LOR 10A, LOR 10B, and PMGI SF 6 from the LNF store. Follow the links to get process specific information for these chemicals.

General LOR thickness table in µm

Product 1krpm thickness 4krpm thickness
LOR 1A 0.2 0.1
PMGI SF5 0.3 0.15
PMGI SF 6 0.4 0.24
LOR 3A 0.6 0.3
LOR 5A 1.0 0.5
LOR 10A & LOR 10B 1.8 0.9
LOR 20B 3.9 1.9
LOR 30B 5.9 2.8

Additional information

  • When baked at 190C LOR will be somewhat conformal
  • When baked at 275C LOR will flow and become planar
  • LOR is compatible with most resists including Ebeam resist

Limitations

  • LOR is soluble in developers so it will continue to undercut the top photoresits for as long as it is developing. Therefore develop time is critical to achieve small features.
  • Exposure will vary depending on substrate
  • Develop time/rate will vary depending on thickness and baking time and temperature of the LOR
  • Bake times for glass are longer and higher temperature