Browse Prior Art Database

Multiple Reflow Titanium Platinum Metallurgy

IP.com Disclosure Number: IPCOM000079258D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Miller, LF: AUTHOR

Abstract

Terminals for semiconductor solder pads can be made metallurgically stable by the use of a titanium-platinum layer. These joints are more resistant to heat treatment cycling than conventional chrome/copper/ gold terminals. When used as a solder wettable terminal on semiconductor devices, glass passivating layers are opened by conventional etching techniques. Thereafter, a thin layer of titanium is applied by suitable means, such as sputtering, in order to seal the openings and provide electrical connection to the device conductors, and simultaneously provide good adhesion to the device itself. Then, a platinum layer of approximately 500-10,000 angstroms thick is applied over the titanium layer to provide a solderable surface.

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Multiple Reflow Titanium Platinum Metallurgy

Terminals for semiconductor solder pads can be made metallurgically stable by the use of a titanium-platinum layer. These joints are more resistant to heat treatment cycling than conventional chrome/copper/ gold terminals. When used as a solder wettable terminal on semiconductor devices, glass passivating layers are opened by conventional etching techniques. Thereafter, a thin layer of titanium is applied by suitable means, such as sputtering, in order to seal the openings and provide electrical connection to the device conductors, and simultaneously provide good adhesion to the device itself. Then, a platinum layer of approximately 500-10,000 angstroms thick is applied over the titanium layer to provide a solderable surface. Solder then can be applied to the titanium layer by well-known methods and, thereafter, conventional processes can be employed to dice the substrates, after which chips are joined by solder reflow.

The titanium has excellent adhesion characteristics and the platinum offers an effective solderable layer. The two layers can be phased in to create a strong mixed region, but still offering a ductile solder joint chip and substrate bonding. Additionally, this system resists metallurgical reactivity and thus enhances the life of the joint.

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