Browse Prior Art Database

Inner Lead Bonding for Tab Package

IP.com Disclosure Number: IPCOM000101471D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Iguchi, Y: AUTHOR

Abstract

Bonding between inner leads and conductive pads on a chip coated with a polyimide layer is improved by proper design of contact openings of the polyimide layer.

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This is the abbreviated version, containing approximately 100% of the total text.

Inner Lead Bonding for Tab Package

       Bonding between inner leads and conductive pads on a chip
coated with a polyimide layer is improved by proper design of contact
openings of the polyimide layer.

      Fig. 1 shows prior inner lead bonding for TAB (Tape Automated
Bonding) packages.  Polyimide layer 12 on chip 10 includes
rectangular openings 14 (only one shown in Fig. 1) which expose chip
pads comprising first level metal M1 and second level metal M2.  At
the time of bonding as by a laser beam or thermode, inner leads 16
(only one shown in Fig. 1) are placed on the chip 10 to lie on
the polyimide layer 12. The height of the polyimide layer 12 and the
concave shape of the chip pads give a relatively large gap between
the inner lead 16 and the chip pads which tends to cause poor
bonding.

      Fig. 2 shows the present bonding structure.  The opening 14 of
the polyimide layer 12 is modified such that the inner lead 16
directly contacts the highest portions of the chip pad when placed on
the chip 10.  This reduces the gap between the inner lead 16 and the
recessed portion of the chip pad, significantly improving bonding
quality.