Lift-off resist
About this Process | |
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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.
- LOR 10A and LOR 10B have similar thicknesses. LOR 10A develops much slower than LOR 10B allowing for features that are closer together.
- PMGI SF 6 can be used for thinner and smaller features and it can be purchased from the LNF Store. Characterization and process information.
- For thicker Metal and larger features LOR 20B and 30B can be used. These are not sold though the LNF store.
General LOR thickness table in µm
Product | 1krpm thickness | 4krpm thickness |
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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