Method of making metallic support carrier for semiconductor elements

US4065851A · kind A · utility

Assignee

• W. C. Heraeus GmbH · DE

Inventors

• Franz Kummer · Munich, DE
• Gerhard Mai
• Rolf Ruthardt · Hanau, DE
• Horst Thiede · Bruchköbel, DE

Key dates

• Filing date: Nov 3, 1976
• Grant date: Jan 3, 1978
• Expiry date: Nov 3, 1996

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49121
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

To improve the bonding layer for connecting wires to semiconductor chips with contact fingers, or contact strips, on a substrate carrier, the bonding layer is formed as spongy, microporous structure, applied to discrete positions of the contact strips by screen printing, and secured to the metallic connecting strip by a diffusion zone. Preferably, the bonding layer comprises a metal of gold, palladium, silver, aluminum and copper, or an alloy of at least two of these metals, or a base alloy of one of these metals, for example gold applied as a gold paste having an average grain size of less than 5 micro-meters, the layer being between 2 to 30 micrometers thick, preferably 3 to 10 micrometers. The metal is part of a paste of the metal in an evaporative organic carrier. After screen printing, the carrier is eliminated by heating; subsequent heating converts the metal to a spongy microporous structure bonded to the substrate carrier by a diffusion zone.