Dear all

I am handling AZ P4620 now. I also was confused by the dose of print and
found with low dose of exposure you can not develop thoroughly. I can
not get the steep wall with recommended dose. My feather is hole with
diameter of 6 um and aspect ratio of above 2.5:1.

My recipe is(on wafer dice with about 20*20 mm)

Spin coating: 500 rpm 8 sec with 250 r/s; 1000 rpm 180 sec with 3000 r/s
(15 um)

Soft bake: 80 C 1 min then goes to 110 C and keep 6-8 min

EBR with tweezer

Expose 40-70 sec with broad band UV and the power is 900 w.

Develop: AZ400K : DI water 1:4, 4-5 min. shaking with hand-holding
tweezer.

Best regards!

XiaoQiang