Browse Prior Art Database

Ground Plane Connection for Three-layer Tapes

IP.com Disclosure Number: IPCOM000099509D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Grandguillot, M: AUTHOR [+3]

Abstract

The technique presented here allows the obtention of a ground plane on TAB tapes. It is based on the cheap standard three-layer technology, thus answering the increasing demand for better signal propagation speed. In such an application: - the first side of metal is for the ground plane; that ground plane decreases the line impedance of the package, and

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Ground Plane Connection for Three-layer Tapes

       The technique presented here allows the obtention of a
ground plane on TAB tapes. It is based on the cheap standard
three-layer technology, thus answering the increasing demand for
better signal propagation speed.
    In such an application:
    - the first side of metal is for the ground plane; that ground
plane decreases the line impedance of the package, and

      - the second side of metal is the connecting layer for the
chip-to-card connection.

      It is, therefore, proposed to process the three-layer tape
technology as usual, but the incoming polyimide tape is replaced by a
metallized polyimide tape. The first metallization can be a copper
layer which is glued or electro-deposited on the polyimide.  At the
beginning of the three-layer tape process, the metallized tape is
punched in the same way as the polyimide is punched for the standard
product.

      At the end of the three-layer tape process the tape will have
two metallized sides:
    1- side 1: the ground plane which will not have any lead.
    2- side 2: the connecting plane, which will ensure all the
chip-to-card connections.

      An appendix of the ground lead (the lead connected to the
ground) will make the link between the ground lead of the connecting
layer on side 2 and the ground plane on side 1, as shown in Fig.
1 which shows a top view of the tape (connecting plane up).

      The new steps of the manufact...