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Segmented Glob Reinforcement for Extra Long Fine Pitch Wire Bond

IP.com Disclosure Number: IPCOM000009246D
Original Publication Date: 2002-Aug-13
Included in the Prior Art Database: 2002-Aug-13
Document File: 4 page(s) / 258K

Publishing Venue

Motorola

Related People

Fuaida Harun: AUTHOR [+3]

Abstract

The invention being disclosed here involves the use of single or multiple segmented reinforcement to hold long multi-tier and/or staggered ultra fine pitch wire bonds in normal, stacked, or MCM packages in their places to avoid wire deformation during glob top or molding which may lead to wire shorting. The invention disclosed here encompasses the art of wire bonding IC packages in very general terms, without reference to any specific package type. The segmented glob epoxy reinforcement can be applied to small and strategic location of the wires. The globbed epoxy can be held suspended on the wires or dispensed through the wire to the solder mask at the bottom. For extra long wires, multiple glob segments may be used for additional reinforcement. The globbed epoxy does not contact the dies.

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Segmented Glob Reinforcement for Extra Long Fine Pitch Wire Bond

 

Fuaida Harun, LC Tan, and CS Foong

Abstract

The invention being disclosed here involves the use of single or multiple segmented reinforcement to hold long multi-tier and/or staggered ultra fine pitch wire bonds in normal, stacked, or MCM packages in their places to avoid wire deformation during glob top or molding which may lead to wire shorting.

The invention disclosed here encompasses the art of wire bonding IC packages in very general terms, without reference to any specific package type.� The segmented glob epoxy reinforcement can be applied to small and strategic location of the wires.� � � The globbed epoxy can be held suspended on the wires or dispensed through the wire to the solder mask at the bottom.� For extra long wires, multiple glob segments may be used for additional reinforcement.� The globbed epoxy does not contact the dies.

Description

Ultra fine pitch wire bonding (35 um and below) are susceptible to wire damage, wire short, and wire sweep (during molding) because of their close proximity, small wire diameter, and multi-tier configuration.� Typical wire diameters are 0.8 um and possibly lower in future wire bond developments.� The use of this invention helps to secure all the wires in their places and hence will eliminate potential wire damage, wire shorts, and reduces wire sweep during molding

The invention being disclosed here involves the use of segmented reinforcement to hold long fine pitch wire bonds in their places to avoid wire deformation during handling or molding which may lead to wire shorting.� In this invention, un-coated fine pitch wires are wire bonded per normal wire bonding process.� Following the wire bonding, thin lines of glob epoxy (or other suitable material) are dispensed across the wires at strategic locations to hold the wires in their places. Once the liquid epoxy is cured, the wires will be held firmly in place.� The concept discussed here is shown in Figure 1.

Figure 1� Multiple Segmented Glob Reinforcement for Ultra Fine Pitch Wire Bonds

Depending on the wire lengths, multiple segments of reinforcements may be used.� Two different reinforcement methods may also be used.� In the first, t...