International Business Machines Corporation

Gregg A Knotts

Mark Kenneth Hoffmeyer

Phillip Duane Isaacs

Miles Frank Swain

Connie Jean Mathison

Burton A Towne

A direct chip attachment process and apparatus for aluminum wirebonding on copper circuitization are provided. After at least one integrated circuit chip is attached to a carrier, an aqueous cleaning solution containing citric and oxalic acid based additives is applied to the carrier and attached integrated circuit chip. Then a deionized water rinse is applied to the carrier and attached integrated circuit chip, followed drying for a set time period. Next wirebonding on copper circuitization carried by the carrier is performed.

Direct chip attachment process and apparatus for aluminum wirebonding on

A technique for filling hollow, plated-through-hole vias in multi-layer printed circuit substrates with solder and then joining the solder filled via with a solder ball on a solder ball connectable electronic module is disclosed. The filling of the vias is accomplished by depositing solder paste on one end of the hollow via and reflowing the solder particles within the solder paste to at least partially fill the PTH via. The depositing of the solder paste and the reflowing operations may be repeated until such time as the via is substantially completely filled with solid solder. The importance of the prefilling of the vias with solder is that the reflowing operation of solder balls or solder paste when joining the multi-layer printed circuit board to the electronic module, will prevent undue wicking or pulling of molten solder from the electrical connection into the PTH via, thereby preventing the formation of solder starved or unreliable electrical connections.

Growing community of inventors

Rochester, MN, United States of America

Gregg A Knotts