Michael Mason (ACSIST/ACSIST/mjmason%Acsist_Associates@mcimail.com)
Wed, 22 Mar 95 09:42 EST

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Date: Wed, 22 Mar 95 09:42 EST
From: Michael Mason
To: TechNet
Subject: Hard water vs. soft water
Message-Id: <93950322144239/0006667643NA2EM@MCIMAIL.COM

I would like to know if anyone out there can explain to me the rational behind using hardwater instead of softwater in our resist developers? We have been told by several different venders that using hard water followed by a reverse osmosis (R.O.) rinse, will give us "better set up of the resist". When I have asked these venders to explain the chemical and physical reasons for this, I have not received an answer. I have always thought that "cleaner water" (ie. soft water) was better but apparently this is not the case.


David T. Novick (David_T._Novick@ccmail.anatcp.rockwell.com)
Wed, 22 Mar 95 10:03:06 PST

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Date: Wed, 22 Mar 95 10:03:06 PST
From: "David T. Novick"
Message-Id: <9502227958.AA795895923@ccmail.anatcp.rockwell.com>
To: TechNet@ipchq.com

I cannot speak with any certainty, but can offer what might be an explanation. Hard water contains considerable mineralization. It might just be possible that these microcrystals act as growth or crystallization sites for the resist, resulting in a fine dispersion rather than large grained, or large polymer growths.