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Piezoelectric Thermode for Thermocompression Shear Bonding

IP.com Disclosure Number: IPCOM000037631D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Noyan, IC: AUTHOR [+3]

Abstract

Disclosed is a device which allows thermocompression (TC) gang- bonding of multi-leaded surface mounted devices, particularly for TAB packaging, while simultaneously imposing a shear displacement to the surfaces to be bonded. This device allows the reduction of bonding temperatures and times and limits the vertical deformation (crush) in the bonding sites on the chip (the pads) required for good joints. It achieves these objectives by supplying energy in the form of a shear wave to the structures being joined.

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Piezoelectric Thermode for Thermocompression Shear Bonding

Disclosed is a device which allows thermocompression (TC) gang- bonding of multi-leaded surface mounted devices, particularly for TAB packaging, while simultaneously imposing a shear displacement to the surfaces to be bonded. This device allows the reduction of bonding temperatures and times and limits the vertical deformation (crush) in the bonding sites on the chip (the pads) required for good joints. It achieves these objectives by supplying energy in the form of a shear wave to the structures being joined.

The device applies the shear force to the joints by a radially expanding and contracting the bonding head (Figure 1) which is manufactured from a high temperature piezoelectric material such as: PbTiO3 (Tc = 492oC), LiTaO3 (Tc = 607oC), Li3Ba4Nb10O30 (Tc = 586oC), Na3Ba3Nb9WO30 (Tc = 460oC), Na2Ba4Nb10O30 (Tc = 560oC), etc. During bonding, the chip is held with a chip cavity, as shown in this drawing, to prevent the movement of the chip along with the bonding head. The heat required for bonding is supplied by a thermode body, attached to the bonding head (the piezoelectric plate) by a vacuum chuck, clip, pressure device or similar attachment which, while holding the piezo-plate in place does not constrain lateral movement.

One example of manufacture is described below: The device is manufactured in two parts. The bonding head is prepared from ceramic greensheets containing the piezoelectric material...