[Photolithography] Negative resist: Spin-coating, baking, exposure and development conditions: AZ nLof 2020

[Photolithography] Negative resist: Spin-coating, baking, exposure and development conditions: AZ nLof 2020

One of the most commonly used negative photoresists is AZ nLof 2020. Here, I make a note on spin-coating, baking, exposure and development conditions of the negative tone photoresist. 

Useful links:

Photoresist informaiton: http://www.microchemicals.com/products/photoresists/az_nlof_2020.html 

Data sheet (pdf): http://www.microchemicals.com/micro/AZ_nLOF2000_bulletin.pdf

AZ 2020 nLof Photoresist negative

1. Spin-coating

- Spin speed: 3000 rpm for 2.0 μm thickness (60 s)

(Data from (pdf): http://www.microchemicals.com/micro/AZ_nLOF2000_bulletin.pdf)

2. Baking

- Soft prebake: 110 ˚C, 60 seconds, hotplate, direct contact

- Postexposure bake: 110 ˚C, 60 seconds, hotplate, direct contact

In case direct contact is not available, for example, for Lithium Niobate substrates (personal parameters)

- Soft prebake: 150 ˚C, 300 s, on a dummy Si wafer, pin-up hotplate, non-contact, lid closed

- Postexposure bake: 150 ˚C, 300 s, on a dummy Si wafer, pin-up hotplate, non-contact, lid closed

(Data from (pdf): http://www.microchemicals.com/micro/AZ_nLOF2000_bulletin.pdf)

3. Exposure

- Exposure:  i-line @ 65 mJ/㎠

- MA6 mask aligner intensity in July 2016: 10.3 mW/㎠ (365 nm), 19.3 mW/㎠ (400 nm)

- Exposure time: 6 seconds (~ 61.8 mJ/㎠)

(Data from (pdf): http://www.microchemicals.com/micro/AZ_nLOF2000_bulletin.pdf)

4. Development

- Developer: AZ 726 MIF (or AZ 300 MIF)

- Development: 60 seconds (single puddle)

 

(Figure: http://www.lithoguru.com/scientist/lithobasics.html)

5. Post development bake

- Post development bake: 150 ˚C, 60 seconds, hotplate

In case direct contact is not available, for example, for Lithium Niobate substrates (personal parameters)

- Soft prebake: 180 ˚C, 300 s, on a dummy Si wafer, pin-up hotplate, non-contact, lid closed

6. Removal (after metal deposition)

- Remover: AZ 400T or AZ 770 Remover

- Alternative remover: TechniStrip® NI555 (http://www.microchemicals.com/products/remover_stripper/technistrip_ni555.html)

- More alternative removers: TechniStrip® D350 (link) or Microchem Remover PG (pdf link)

- Removal: 10 minutes immersion

- Sonication if required

17 October 2016 

Coherent Harmonic Oscillator 

겨울떨개