Browse Prior Art Database

Plug and Socket Chip Joining

IP.com Disclosure Number: IPCOM000046541D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Jones, HC: AUTHOR [+2]

Abstract

Defining socket areas in a photoresist dielectric, and using solder plugs to make alloy contacts to pads located in the sockets, permits a simple bonding process to be used with complicated circuits which are easy to handle during intermediate process steps or storage. The previous controlled collapse process used to bond chips to the chip carrier requires both deposition of the interface metallurgy and the solder on both pieces to be bonded by controlled collapse of the solder during heating. The bonding takes place because of the reduction in surface energy of the combined melt under the weight of the chip. This process (shown schematically in the figure) has solder plugs deposited only on one of the two parts to be bonded; the other part has a coating of photoresist dielectric.

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Plug and Socket Chip Joining

Defining socket areas in a photoresist dielectric, and using solder plugs to make alloy contacts to pads located in the sockets, permits a simple bonding process to be used with complicated circuits which are easy to handle during intermediate process steps or storage. The previous controlled collapse process used to bond chips to the chip carrier requires both deposition of the interface metallurgy and the solder on both pieces to be bonded by controlled collapse of the solder during heating. The bonding takes place because of the reduction in surface energy of the combined melt under the weight of the chip. This process (shown schematically in the figure) has solder plugs deposited only on one of the two parts to be bonded; the other part has a coating of photoresist dielectric. The photoresist dielectric is exposed and etched to leave sockets for the solder plugs on the other part. The photoresist dielectric should have the following properties: A. It must have chemical stability. B.

It can be deposited, exposed and properly etched for thicknesses as great as .05 mm or more. Bonding is done by aligning the plugs of one part over the sockets of the matching part after an appropriate cleaning. The parts are heated, and the bonding takes place between the plugs and the interface metallurgy. Ultrasonic bonding is also a viable bonding process. The bonding between the plug and the interface metallurgy (which may be AuPd) is more favorab...