Browse Prior Art Database

Chip Conversion

IP.com Disclosure Number: IPCOM000052867D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 72K

Publishing Venue

IBM

Related People

Ward, WC: AUTHOR

Abstract

There are two basic techniques for mounting semiconductor chips on substrates. One technique is the so-called wire bonding which utilizes wire leaders from the face of the chip, and the other is the so-called flip-chip bonding wherein pads of metal are evaporated onto the face of the chip. Most of the manufacturers making wire-bonded chip are not equipped for providing pads on chips for flip-chip bonding, but it is often desirable to connect wire-bonded chips by flip-chip-bonding methods. For various reasons it is often not practical or possible to purchase a wafer and convert the whole uncut wafer to flip-chip-bonded pads and it is not economically feasible or practical to convert an individual chip from wire-bonded to flip-chip-bonded connections.

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Chip Conversion

There are two basic techniques for mounting semiconductor chips on substrates. One technique is the so-called wire bonding which utilizes wire leaders from the face of the chip, and the other is the so-called flip-chip bonding wherein pads of metal are evaporated onto the face of the chip. Most of the manufacturers making wire-bonded chip are not equipped for providing pads on chips for flip-chip bonding, but it is often desirable to connect wire-bonded chips by flip-chip-bonding methods. For various reasons it is often not practical or possible to purchase a wafer and convert the whole uncut wafer to flip-chip- bonded pads and it is not economically feasible or practical to convert an individual chip from wire-bonded to flip-chip-bonded connections. This article describes a practical technique for taking a multiplicity of wire-bonded connection chips, replicating a wafer format of the chips, and then providing the desired metal pads for flip-chip bonding on all of the chips simultaneously in the replicated wafer format.

In practicing this invention, a precision die handling system is required which can pick up a semiconductor chip and accurately align the chip to very close tolerances with respect to X,Y and Z axes and the correct angle B. One such system is the Tacmatic Die handling System manufactured by Teledyne Corporation.

As shown in Fig. 1, the present technique utilizes a conventional molybdenum mask 10 of the type used for the deposit of the various layers of metal to form the pads on an uncut wafer. This mask 10 provides a base on which to place the chips 20. The mask 10 includes conventional through openings 12 which are positioned at the locations where metal pads are to be f...