Cleaning and liquid contact with solids – Processes – For metallic – siliceous – or calcareous basework – including...
Patent
1990-08-06
1991-07-30
Morris, Theodore
Cleaning and liquid contact with solids
Processes
For metallic, siliceous, or calcareous basework, including...
134 3, 134 26, 252 794, 156651, 156656, 156664, C23G 100
Patent
active
050357492
ABSTRACT:
Disclosed is a method for removing a layer of tin or tin-lead alloy from a copper substrate of a printed circuit board employing the two different reagents in a two-step procedure without damaging the substrate, and at the same time, preventing formation of whitish precipitates in the treating solution.
In the first step, the layer of tin or tin-lead alloy is selectively removed with the first reagent having a comparatively mild oxidation capability, then in the second step the intermetallic layer consisting of tin and copper is removed with the second reagent having a comparatively strong oxidation capability.
This process ensures a smooth and effective operation in the production of high quality printed circuit boards.
REFERENCES:
patent: Re32555 (1987-12-01), Czaja
patent: 4374744 (1983-02-01), Kawanabe et al.
patent: 4379834 (1983-04-01), Herwing et al.
patent: 4397753 (1983-08-01), Czaja
patent: 4687545 (1987-08-01), Williams et al.
patent: 4713144 (1987-12-01), Schiller
Haruta Takashi
Kishimoto Takeyoshi
Nagano Takaharu
Yamada Yasushi
Yuno Tomoko
Chaudhry Saeed
MEC Co. Ltd.
Morris Theodore
LandOfFree
Process for removing tin and tin-lead alloy from copper substrat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for removing tin and tin-lead alloy from copper substrat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for removing tin and tin-lead alloy from copper substrat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1540861