Browse Prior Art Database

Specially Shaped Chip Carrier Interface to Lead Frame

IP.com Disclosure Number: IPCOM000106922D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Belazzouz, M: AUTHOR [+2]

Abstract

Disclosed is an improved design of a wire-bonded chip carrier substrate. The improved design will allow a 50-mil-thick substrate, carrying a chip which is bonded to a lead frame to fit within the specifications of a metallized ceramic (MC) tool in a manufacturing process. This improvement has the advantage of reducing the overall thickness of the package. See Figs. 1, 2 and 3.

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Specially Shaped Chip Carrier Interface to Lead Frame

       Disclosed is an improved design of a wire-bonded chip
carrier substrate. The improved design will allow a 50-mil-thick
substrate, carrying a chip which is bonded to a lead frame to fit
within the specifications of a metallized ceramic (MC) tool in a
manufacturing process. This improvement has the advantage of reducing
the overall thickness of the package. See Figs. 1, 2 and 3.

      The improved substrate design has a cavity in which the chip is
bonded. The depth of the cavity is equal to the thickness of the
chip.  The lead frame sits on a recess cut around the perimeter of
the sub strate. By making the recess equal to one half the thickness
of the substrate to accommodate the lead frame, the lead frame can be
positioned midway on the substrate. The result is a flat lead frame
package. See Fig. 2.

      The substrate can be made of aluminum oxide, or silicon carbide
or TEFLON*, and the wire bonds can be either aluminum, copper,
chromium or a mixture thereof. The wire bonds can be formed on the
substrate using an appropriate process including evaporation,
sputtering or etching, and the carrier can be molded or protected
with a conformal coating.
*  Trademark of E. I. du Pont de Nemours & Co.