Browse Prior Art Database

Direct Chip Transfer Attach Bonding

IP.com Disclosure Number: IPCOM000100623D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Overfield, PRB: AUTHOR [+3]

Abstract

The disclosed concept is designed to overcome the shortcomings of present TAB packaging. The TAB carrier does not allow proper cleaning of outer lead bonds after soldering and requires a two-step process for inner lead bonds and outer lead bonds. Other manufacturing difficulties are experienced in TAB assembly due to the fragile nature of the leads and relate to handling during pick, excise, form and place operations prior to solder reflow. The package described overcomes these concerns.

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This is the abbreviated version, containing approximately 91% of the total text.

Direct Chip Transfer Attach Bonding

       The disclosed concept is designed to overcome the
shortcomings of present TAB packaging.  The TAB carrier does not
allow proper cleaning of outer lead bonds after soldering and
requires a two-step process for inner lead bonds and outer lead
bonds.  Other manufacturing difficulties are experienced in TAB
assembly due to the fragile nature of the leads and relate to
handling during pick, excise, form and place operations prior to
solder reflow.  The package described overcomes these concerns.

      The essential details of the disclosure are shown in Figs. 1
and 2.  The two schematics differ in the construction of heat-sink
details.  The printed circuit carrier has a fan-out pattern for outer
lead bonds (OLBs) and a cavity for the chip.  The chip carries the
inner lead bond (ILB) pads.  The beam lead pattern is fabricated to
the spacings and shape of ILB and OLB fan-out on a transfer carrier.
To complete the assembly of ILB and OLB joints, the transfer carrier
is aligned to the printed circuit carrier and gang bonded, using
temperature and pressure. Fiducials are used to align the two
carriers.

      The described packaging scheme allows both ILB and OLB to be
bonded in one step.  It also permits visual inspection and 100
percent testability of joints.  In addition, the absence of tape
allows thorough cleaning prior to encapsulation.  There are other
advantages such as no excising and forming of leads, no han...