Browse Prior Art Database

Specifically Located Aqueous - Plating Mask Process

IP.com Disclosure Number: IPCOM000101620D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Freeman, MT: AUTHOR [+2]

Abstract

Disclosed is a process for selectively applying aqueous photoresist to printed circuit boards as a mask prior to nickel/gold or palladium nickel plating.

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This is the abbreviated version, containing approximately 70% of the total text.

Specifically Located Aqueous - Plating Mask Process

       Disclosed is a process for selectively applying aqueous
photoresist to printed circuit boards as a mask prior to nickel/gold
or palladium nickel plating.

      Narrow strips of aqueous photoresist are applied by resist
laminator (free standing or in-line - See Figs. 1 and 2) to selective
areas of the printed circuit board.  This lamination step replaces
the current tape application machine prior to nickel/gold plate.
Selective application of the resist eliminates the need for
photoresist development.  Exposure of the photoresist takes place by
means of a "blanket expose" lamp in-line with the resist laminator.

      The panel is then plated conventionally with nickel/gold (free
standing or in-line - See Figs. 1 and 2). Following plating, the
panel is processed through a NaOH strip chamber to remove the
photoresist mask.

      Essential features of the disclosure are as follows:
      1)   Aqueous photoresist after "blanket expose" is chemically
resistant to the pH of the subsequent plating solutions.
      2)   Cross linking of the photoresist results in a required
stripping pH of 14.
      3)   Of the planned plating chemistries, the most alkaline is
Pd/Ni at 8.3 pH.

      The novelty of the process is that it does not use
adhesive-based tapes or full-panel resist apply with a develop
operation to mask the panel, which are currently the industry
standards.  The selec...