hello: I am in charge of poly etch back for trench, using cl2/HBr/He-O2 gases.
etch back short loop flow: 1 poly etch back P5000 2 50:1 HF SCP 60 Second 3 SEM
S-4700 After dipping the wafer using 50:1 HF about 60 Sec. I send wafer to
S-4700 for checking poly recess depth. It seems that there is a white spike
residue on the trench groove as showing in the attachment picture. I have try to
remove the white spike by using B-Clean, and other chemical acid. But I am fail,
Can you give me some advices? Thanks!