Browse Prior Art Database

Field Assisted Bonding of Multilayer Packages

IP.com Disclosure Number: IPCOM000051206D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Lane, R: AUTHOR

Abstract

This article describes a new technique of bonding and hermetically glass sealing semiconductor chips to a substrate. The process uses the pressure developed while performing field-assisted bonding to compress a metal line on the substrate to metal contact on the chip.

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Field Assisted Bonding of Multilayer Packages

This article describes a new technique of bonding and hermetically glass sealing semiconductor chips to a substrate. The process uses the pressure developed while performing field-assisted bonding to compress a metal line on the substrate to metal contact on the chip.

Fig. 1 shows a cross section of a chip and the substrate. A diffused contact is made on the chip through the SiO(2). The contact is metallized with a ductile metal, such as Au, Cu, or A1. A Hf film is deposited on the SiO(2). The film thickness is between 100 Angstrom and 300 Angstrom The purpose of this film is for bonding. The substrate has the metal lines (Au, Cu, A1, etc.) deposited on it.

If via holes are desired in the substrate, they may be machined by either E-beam milling or ultrasonic machining. Alignment is achieved by viewing through the substrate. A field is applied between a negative substrate and a positive chip. The package is heated to 250 degrees C, at which temperature bonding takes place between the Hf film on the chip and the substrate. The Hf converts to HfO(2) during the bonding, so the contact pads do not short out to each other. The projecting pads and lines 3,000 Angstrom above each surface are compressed together, and all the contact pads are hermetically sealed by the bonded surfaces.

Fig. 2 shows two layers of a multilayer package. Conducting vias have pads on them made of a ductile metal. Each layer may have interconnecting...