From mbadi at relgyro.stanford.edu Tue Sep 11 18:31:06 2001 From: mbadi at relgyro.stanford.edu (Mohammed H. Badi) Date: Tue, 11 Sep 2001 18:31:06 -0700 (PDT) Subject: reservation time freed up Message-ID: hi all, i've been having some trouble with my wafers and can't use my time tonight and most of tomorrow. sorry for the late notice. moe. -------- Mohammed H. Badi 650-906-0663 From yyao at intpax.com Mon Sep 24 20:42:09 2001 From: yyao at intpax.com (Yahong Yao) Date: Mon, 24 Sep 2001 22:42:09 -0500 Subject: mask for KOH etching Message-ID: <3BAFFD11.37574110@intpax.com> Dear All, Recently, I always met problems when I conducted the KOH through wafer etching. Film stack is: Nitride (4000A)/PolySi(3000A)/Nitride(4000A). Backside has the same stack. I opened the backside for KOH etching. Front side is covered by Nitride (no KOH openings). After two hours KOH etching, the front side had a lot of blisters. It seems Nitride was broken therefore the underlying PolySi was etched rapidly and worsened the situation. More interesting thing was when I didn't open the backside, just threw a wafer with film stack in KOH, after two hours, the front side was good. No blisters were observed. I tried different Nitride recipe: LONH378 and NITRIDE2. Both had the problem. I changed to TMAH solution, problem was still there. Any suggestion? Thank you in advance. Yahong -- Yahong Yao, Ph. D. Phone: (408) 252-6410 x. 407 Mobile:(408) 718-8831 Fax: (408) 252-6430