AZ 12XT is a chemical enhanced positive tone photo resist (PR). In a chemical enhanced PR the exposure step creates a latent image and a week acid in the PR. The chemical reaction that makes the PR soluble in developer happens during the post exposure bake (PEB). This makes the length and temperature of the PEB extremely important. One of the advantages of the chemical enhance resits for thick resist is that it eliminate the waiting steps. The resist holds up well in RIE, DRIE, wet etching and plating. We have seen some PR cracking after gold platting but have had no plating in the cracks or peeling of the PR.
|About this Process|
|Chemicals Used||AZ 12XT, AZ 726|
Users should note that this is not a DNQ resist and is not compatible with the image reversal process used in the YES-310TA.
for 10-25um layers
- HMDS in YES Image Reversal Oven
- Spin AZ 12xt
- When dispensing the AZ 12xt try to spread the puddle around as you dispense. You can get good even coverage with less resist this way.
- AZ 12xt is a high viscosity resist and will create stringers or cotton candy when spun.
- For 4 inch or larger samples you need to knock down the stringers with a swab or acetone between samples.
- 2-4K 3 minutes on a 110°C hotplate with the lid lowered
- 1K 4 minutes on a 110°C hotplate with the lid lowered
- Exposure (see characterization data below)
- 10-17um layers
- Contact Aligners 12-16 sec
- Stepper 0.22-0.24 sec, Focus:-50
- Contact Aligners 20-24sec
- 10-17um layers
- Post Exposure Bake
- For 3 and 4k spins - 1 minute on a 90° hotplate with the lid lowered
- For a 2K spin - 1.5 minutes on a 90° hotplate with the lid lowered
- For a 1K spin - 4 minutes on a 90° hotplate with the lid lowered
- Develop on the CEE Develop stations using 726 DP 60-60
- Hard Bake
- Wet processing: hard bake at 110°C for 1 minute
- If wafers have been through a plasma you MUST start with a Oxygen ash to remove most the pr. You can follow with PRS-2000 or nanostrip
- If wafer have been through any other process you can use Oxygen plasma, PRS-2000, or nanostrip.
AZ 12xt spin curve on the CEE 100
- Contact Aligners: Exposure time vs Spin Speed
- Contact Aligner: 1K spin, Softbake and PEB tests
- Contact Aligner: Exposure time vs Development time. 1K spin CEE 100.
- Exposure time vs Focus on Stepper
- Wet Etch
- Step Coverage