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An Aqueous Cleaning Method for Drill Tape Residue

IP.com Disclosure Number: IPCOM000107227D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Baldovin, TJ: AUTHOR [+4]

Abstract

Disclosed is a new method for preventing the deposition of drill-tape residue on printed circuit boards.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 90% of the total text.

An Aqueous Cleaning Method for Drill Tape Residue

      Disclosed is a new method for preventing the deposition of
drill-tape residue on printed circuit boards.

      Polyester based drill-tapes, used in masking the epoxy surface
of printed circuit boards from drill-hole cleaning
solvents/solutions, are known to leave a sticky residue on the epoxy
surface, after peeling off the tape from the board.  The presence of
this residue on the epoxy surface of the board can cause a plating
void (unplated area) after copper plating the board.  The drill tape
residue can be cleaned using the solvent methylenechloride, an ozone
depleting agent, which it is desired to eliminate from industrial
processes.  The following alternate method involves applying an
aqueous soluble resist Riston 3120 (du Pont trademark) to the board
prior to drill-tape application followed by drilling and
hole-cleaning.  After peeling off the drill tape, the resist can be
stripped by aqueous basic (1.5% sodium hydroxide) solution, without
using any solvent.

      Boards were run through the processes as mentioned above,
followed by seed application and copper plating. Evaluation of the
copper plated boards by X-ray and 100% visual inspection did not show
any plating voids on the surface or inside drilled-holes.

      The reason for void-less copper plating is obviously due to the
deposition of drill-tape residue on the resist surface (instead of on
the epoxy surface).  Efficient stripping ...