# Photolithgraphy 

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This page is still under active development
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## Equipments
- Maskaligner
- Spin-corter
- Clean room

## Materials & Reagents

- SU-8 2100
- SU-8 RG remover
- SU-8 developer
- IPA
- Silicon wafer

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## Protocols

1. Clean the wafer with acetone and IPA, and spin it fast to dry.
2. Dispense about 4 ml of SU-8 2100 onto a cleaned and dehydrated 6-inch silicon wafer.
3. Coat the dispensed SU-8 uniformly on the wafer using a spin coater at 500 rpm for 10 seconds with an  acceleration of 100 rpm/sec and then sequentially spin at 1500 rpm for 30 sec with an acceleration of 300 rpm/second.

4. Soft bake the wafer for 10 min at 65 °C and for 40 min at 95 °C on a hot plate.

```{important}
Keep the coated wafers level. Although different combinations of photoresist, spin parameters and baking time can be used to generate a layer with a given thickness, we recommend the specific SU-8 photoresist formulations and spin rates that we report here, which have been optimized. I The procedure for spin-coating photoresist, photolithography, and wafer development is dependent on the specific equipment used and the process parameters (e.g., humidity, temperature, gas pressure, and UV intensity).
```

5. Use a transparency photomask printed over 20,000 dpi positioned over the wafer to produce the master by exposing the wafer to an appropriate dose of UV light as per Microchem’s protocol (350-370 J/cm2).
6. After exposure, bake the wafer for 5 min at 65 °C and for 15 min at 95 °C on the hot plate.
7. Develop 20 min in SU-8 photoresist developer. Rinse the substrate briefly with SU-8 Remover RG and IPA and gently dry it with pressurized nitrogen gas.
8. The wafer was baked for 3 min at 150℃ in the oven.