International Business Machines Corporation

Anthony F Arnold

Arnold F Schmeckenbecher

Da-Yuan Shih

Willi Volksen

Mahmoud M Khojasteh

Donald Clifford Hofer

Elwood Herbert Macy

Walter F Lange

Ying Ying Cheng

Prabodh R Shah

Richard E Gegenwarth

Richard D Diller, Deceased

Patricia M Cotts

Shukla Kapur

Joseph A Corso

A method of making integrated circuit chip to substrate connections first deposits a blanket layer of CrCu over a completed wafer which has terminal vias etched in the final insulator. Then PbSn solder is electrolytically plated through a photoresist mask. After the plating is done, the resist is removed and the Cu is etched using the solder dot as a mask, and then the solder dots are melted to form spheroid or ball shapes. Next, a positive photoresist is applied in a manner that distributes the photoresist around the base of the solder balls. The solder balls are then used as a self-aligned exposure mask. Since the photoresist under the balls is not exposed, each ball has a concentric layer of resist at the base after exposure and development. This concentric layer of resist protects the Cu/PbSn interface and is used as the mask for etching excess Cr. The resist is then removed.

Resist protection of ball limiting metal during etch process

A composition for the application of a planar polyimide coating having a glass transition temperature above 300.degree. C. comprises a solution in an anhydrous, aprotic solvent of an aromatic diamine and a dialkyldihydrogen pyromellitate which is more than 90% meta isomer.

Polyimide coating compositions based on meta-dialkyldihydrogen

A multilayered thin film structure for attaching input/output pins to a ceramic substrate, and method of making the thin film structure are disclosed. A thin adhesion layer, which can suitably be a refractory metal such as titanium, vanadium, chromium or tantalum, is first formed on the surface of the substrate. A thick stress reducing layer of soft metal such as copper, silver, nickel, aluminum, gold or iron is subsequently formed over the adhesion layer. To prevent the soft metal from reacting with subsequently brazed gold-tin pin eutectic alloy, a reaction barrier layer which can be titanium or zirconium is then deposited over the soft stress reducing metal cushion layer. The process is completed by finally depositing a gold layer over the reaction barrier layer.

Multilayer thin film metallurgy for pin brazing

A process for forming a high density solder pad and fan-out metallurgy system in a ceramic substrate wherein a pattern of indented lines is formed in the surface of a green ceramic substrate, the lines filled with a conductive metal paste, a layer of dielectric green ceramic material deposited over at least a portion of the area of the pattern of indented lines, and sintering the resultant substrate.

Process for forming a high density metallurgy system on a substrate and

Growing community of inventors

Poughkeepsie, NY, United States of America

Anthony F Arnold