Browse Prior Art Database

Transparent Flip Chip for Monitoring Flux Cleaning

IP.com Disclosure Number: IPCOM000085210D
Original Publication Date: 1976-Mar-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Herdzik, RJ: AUTHOR [+3]

Abstract

The removal of flux residue from under product flip chips or wafers soldered to a substrate, is monitored by use of a transparent test chip provided with the same connection metallurgy as the product chips or wafers.

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Transparent Flip Chip for Monitoring Flux Cleaning

The removal of flux residue from under product flip chips or wafers soldered to a substrate, is monitored by use of a transparent test chip provided with the same connection metallurgy as the product chips or wafers.

Clear glass chip 1 is provided with a number of solder pads 2 which are attached to chip 1 by evaporated Cr-Cu-Au metallurgy 3, in the same manner as in the case of product flip chips or wafers, not shown. Chip 1 is placed over ceramic substrate 4 having an interconnection pattern 5 matching pads 2. After the solder is reflowed to establish connection between pattern 5 and pads 2, the assemblage is cleaned to remove the flux residue from under the chip 1 and around the pads 2. The test and product wafers may be processed at the same time.

By examining the substrate surface through the transparent test chip 1 during the chip joining operation, the effectiveness of the cleaning procedure can be assessed and the optimum cleaning time can be determined for removing flux residue underneath the product chips and around the solder pads.

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