Browse Prior Art Database

BENDING AND USING TUNGSTEN NEEDLES FOR ELECTRICAL CONTACTS ON BUMP PROCESS PLATING HOODS

IP.com Disclosure Number: IPCOM000007064D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2002-Feb-22
Document File: 1 page(s) / 43K

Publishing Venue

Motorola

Related People

Robert L. Kelley, Jr.: AUTHOR [+2]

Abstract

The 5 inch bump plating process for flip chip was experiencing non-plating and missing plating on bumped wafers. The wafers with non-plated bumps are scrapped.

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MOTOROLA INC. Technical Developments Volume20 October 1993

BENDING AND USING TUNGSTEN NEEDLES FOR ELECTRICAL CONTACTS ON BUMP PROCESS PLATING HOODS

by Robert L. Kelley, Jr. and M. Carmen Brown

contact to contact resistance of 20 OHMS or more. The tubing bend would break under the plastic tub- ing resulting in poor or no plating. The tubing made quite a large gouge in the wafer. This could cause damage to the saw blade in the wafer sawing.

PROBLEM

  The 5 inch bump plating process for flip chip was experiencing non-plating and missing plating on bumped wafers. The wafers with non-plated bumps are scrapped.

SOLUTION

PRIOR ART

  The 5 inch plating fixture used a piece of stain- less steel surgical tubing, cut with diagonal cutters. The tubing gouged through the photoresist to make contact with the sputtered copper beneath. This con- tact was not always good. Many times there was a

  We used a standard 1%" long tungsten needle, normally used for wafer probing, bent it for use in our present fixture, and found the contact to contact resistance to have dropped to under 1 ohm. These needles have never been used as an electro-plating current contact device.

Tungston needle bending and application.

7

Photoresist -

WAFE2

6 Motorola. Inc. 1993 151

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