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Plating and Tinning Technique for Screened Rh Conductors

IP.com Disclosure Number: IPCOM000052041D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Glasspool, WO: AUTHOR [+2]

Abstract

We have developed a technique to remove the hard film of rhodium oxide and then plate copper over screen conductors using an alkaline plating bath. This provides a desirable tinning characteristic.

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Plating and Tinning Technique for Screened Rh Conductors

We have developed a technique to remove the hard film of rhodium oxide and then plate copper over screen conductors using an alkaline plating bath. This provides a desirable tinning characteristic.

It is accomplished by the following steps: 1) The parts are cleaned thoroughly in tribasic sodium phosphate solution using mild ultrasonic at about 65 degrees C, followed by rinsing and drying. Immediately, they must be cleaned in solvent at about 55 degrees C using mild ultrasonic. 2) All the contacts must be shorted together at the end opposite to the terminals. This is accomplished by using Ag conductive epoxy or a 100% metal contact, such as sputtered metal. 3) Electrochemically etch rhodium oxide using 4% KOH solution (weight percent) at 6 V for 5 minutes. It will remove the film of rhodium oxide, leaving behind a fresh layer of rhodium. 4) Rinse parts in deionized water and perform electroplating for copper using copper pyrophosphate bath. The current density is 24 APF, the pH is maintained at 8.3, and the operating temperature is 40/45 degrees C. Plating must be carried out for 6 to 8 minutes. 5) Rinse and dry the parts. 6) Tin pads using eutectic solder and active flux.

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