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Method of Protecting Plastics (Polyimide, Epoxide) during the Plasma Dry Etching Process of Printed Circuit Boards

IP.com Disclosure Number: IPCOM000117639D
Original Publication Date: 1996-Apr-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Kohler, R: AUTHOR [+4]

Abstract

Disclosed is a method for protecting plastics during the Plasma dry etch process. The protection of selective areas is done using a special ink. With this repair method, the scrap rate for Printed Circuit Boards (PCB) can be minimized.

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This is the abbreviated version, containing approximately 68% of the total text.

Method of Protecting Plastics (Polyimide, Epoxide) during the Plasma
Dry Etching Process of Printed Circuit Boards

      Disclosed is a method for protecting plastics during the Plasma
dry etch process.  The protection of selective areas is done using a
special ink.  With this repair method, the scrap rate for Printed
Circuit Boards (PCB) can be minimized.

      The method is used during manufacturing of PCB, where different
plasma etchable materials are used.

To protect the dielectric layer in the plasma process, the following
method is used:

Process steps:
  1.  After lamination of photoresist on the raw material (i.e., Cu
       foil with polyimide as dielectric), a dot pattern will be
exposed
       with film or glassmaster.  This pattern will be delveloped,
       etched and stripped.  The result are etched holes in the
copper
       foil, and the dielectric layer is visible and can be etched in
       the following plasma etch step.
        Dirt on the film or the glassmaster has the same effect as
       a regular dot, causing voids or additional holes in the copper
       foil.  These additional holes are not allowed in certain areas
of
       the PCB; i.e., in areas where the PCB design requires
dielectric
       material between conductors.
      o  To prevent scrap, the polyimide must be protected in these
          areas.
      o  This can be obtained by applying a...