Step 11. Nitride removal

Step	Process	Date	Operator
11.1	Photoresist strip Matrix 2.5 min O2 ashing	06/08/07	Pongracz
11.2	Standard clean wafers Sink8 Piranha	06/08/07
11.3	Nitride wet etch Sink7 - fresh phosphoric acid (3 bottles) @ 160 ^oC - water dripping 1 drop/10s to keep the liquid level - no HF dip before Etch rate slows down from 27 A/min (fresh) to 17 A/min W# 3,4,5,6,7,8,9 125 min W# 1,2,10,11,12,13,14,15 140 min Monitor the etch rate after 50 min, 100 min (QDR, SRD) Measure oxide/nitride thickness with Nanoduv Oxide thickness after etching ~ 250 A, ~100 A on opened areas	06/12/07
11.4	Pad oxide wet etch 5:1 BHF @ Sink8 until PCH dewet ~ 45 s	06/18/07