International Business Machines Corporation

Viswanadham Puligandla

Michael A Gaynes

Jerzy Maria Zalesinski

Charles Gerard Woychik

Alan J Emerick

Ravi F Saraf

Judith Marie Roldan

Richard B Booth

Lenas J Hedlund

Deepak K Verma

Robert M Murco

Robert M Murcko

Chip stacks with decreased conductor length and improved noise immunity are formed by laser drilling of individual chips, such as memory chips, preferably near but within the periphery thereof, and forming conductors therethrough, preferably by metallization or filling with conductive paste which may be stabilized by transient liquid phase (TLP) processes and preferably with or during metallization of conductive pads, possibly including connector patterns on both sides of at least some of the chips in the stack. At least some of the chips in the stack then have electrical and mechanical connections made therebetween, preferably with electroplated solder preforms consistent with TLP processes. The connections may be contained by a layer of resilient material surrounding the connections and which may be formed in-situ. High density circuit packages thus obtained may be mounted on a carrier by surface mount techniques or separable connectors such as a plug and socket arrangement. The carrier may be of the same material as the chip stacks to match coefficients of thermal expansion. High-density circuit packages may also be in the form of removable memory modules in generally planar or prism shaped form similar to a pen or as a thermal conduction module.

High density integrated circuit packaging with chip stacking and via interconnections

High density integrated circuit packaging with chip stacking and via

A simple process for card assembly by Direct Chip Attachment (DCA) uses electrically conductive adhesives. Two methods create the same intermediate wafer product with a layer of insulative thermoplastic and conductive thermoplastic bumps. After sawing or dicing the wafer to form the chips, the chips are adhered to chip carriers with conductive pads which match the conductive thermoplastic bumps, using heat and pressure. Chips may be easily removed and replaced using heat.

Direct chip attachment (DCA) with electrically conductive adhesives

A method for electroless nickel plating of silicon-iron which has been heat treated prior to the plating operation and subjected to thermal shock after the plating operation includes the steps of cleaning the surface of the silicon-iron with a fluoride etch salt, forming a thin deposit of palladium on the clean surface of the silicon-iron, hardening the palladium deposit by treatment with a solution of ammonium hydroxide and nickel plating the silicon-iron using an electroless nickel plating solution, followed by baking at about 250.degree. F. for about six hours.

Palladium activation of 2.5% silicon iron prior to electroless nickel

An oil-based corrosion inhibitor containing an aliphatic amine, a fatty acid and its ester, and an organotin compound provides improved corrosion resistance to metals and is easily removed when the metals are to be processed.

Corrosion inhibiting compositions for metals

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Lewisville, TX, United States of America

Viswanadham Puligandla