We have few chronic issues that need constant followup, and today I updated the status as below:
Under etch issue
Dry etch feedback whole lot seen with ITO ue. Inspected only 7 wfrs and as above seen with the circular signature around the edges of wfr with slot #14 most severe.
Remaining wafers only seen with the whitish ring at the wfr RHS. Checked under scope, brown pad seen everywhere.
Buddy run inspected good. Lot run before, tagged back to inspect also good.
Inspected under DF, photodiode no rsd. Etch Rate check before run at 344 and 355 (at edges). Talked to Hyini but do not want to accept back lot. Pls help to send email to them
Black Particle issue
Lot 44/45 hit with severe/mild Black Particle. Rework done and moved.
Both tools released. As per Engineer, to check severity. If severe, to ground tool and inform him. If BLACK PARTICLE still mild, to continue to run.
Took the Au Etch Rate wafer prepared to check ER in 3B(2mins), no loss observed. Pre ave: 9279, Post Ave: 9278. Wfr placed back in the blue box slot 25. To etch using 65mins and measure pre/post RS reading. To check backside (w photos).
Au Etch rate wafer run 65mins no loss.pre avg:9266,post avg:9262 A . Another 7 lots hold for black particles, To chk lot list in common drive. 2 lots severe lots unable to clear particles even after 2x rwk. maybe need to dip
Another 5 lots done rework & inspection no more.
Need to ask TA to change chemical for 3B and run. 4B to remain down. 50/65mins process to run only in 5B at BL 10-50.
