Browse Prior Art Database

C-4 Joint Structure

IP.com Disclosure Number: IPCOM000051369D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Bartush, TA: AUTHOR [+2]

Abstract

A C-4 joint structure is formed by combining a vertical wire process an a top round and reflow process to provide improved stress, thermal and electrical properties.

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C-4 Joint Structure

A C-4 joint structure is formed by combining a vertical wire process an a top round and reflow process to provide improved stress, thermal and electrical properties.

Substrate 1 carries metal layer 2 and quartz layer 3 with a vertical wire via 4 connection of Al-Cu formed by a combination of the metal lift-off and reactive ion etch processes. The ball limiting metallurgy (BLM) 6 is formed of Cr-Cu-Au or Cr-Cu-Ni-Au. Pb/In solder 7 is formed by flux reflowing at 160 degrees C. The vertical wiring avoids BLM side wall neck down, undercutting and etch bias of conventional via formation. The low temperature and top round provides a uniform inter-metallic structure.

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