Browse Prior Art Database

Flexible Film Chip Carrier with Fine Line Capabilities

IP.com Disclosure Number: IPCOM000121753D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Busacco, RA: AUTHOR [+3]

Abstract

Disclosed is a method whereby circuit lines requiring different values of copper line thickness and/or width can be selectively achieved on the same chip carrier. For example, inner leads (ILs) with narrow widths and thin copper for chip bonding may be used, and outer leads (OLs) with wider widths and thicker copper for strength and stability for bonding to the card may be used.

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

Flexible Film Chip Carrier with Fine Line Capabilities

      Disclosed is a method whereby circuit lines requiring
different values of copper line thickness and/or width can be
selectively achieved on the same chip carrier.  For example, inner
leads (ILs) with narrow widths and thin copper for chip bonding may
be used, and outer leads (OLs) with wider widths and thicker copper
for strength and stability for bonding to the card may be used.

      Two options, "A" and "B", are described as follows (also see
the figure):
      Option "A":  Single-layer carriers (circuitry on one side only)
will have two photoresist and copper plating operations,
respectively.  The first expose and plating operation would provide
the thinnest copper thickness resulting in narrow widths, and the
second expose and plating operation would provide for the larger
widths. Separate resist associated operations such as "develop and
strip" would need to be performed accordingly.  The result would be a
carrier having ILs with one thickness versus the OLs with another
thickness (fine lines and spaces in the ILs and thicker lines in the
OLs).
     Option "B":  Double-layer carriers with copper on both sides
require only one photoresist and copper plating operation.  Both
sides are applied with different thicknesses of resist respective to
the desired line widths.  "Plated-thru" via holes are necessary to
provide the desired electrical connection between the top and bottom
levels. ...