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