International Business Machines Corporation

Other

Kurt R Grebe

Linda C Matthew

Michael J Palmer

Ho-Ming Tong

Ephraim Bemis Flint

Peter Alfred Gruber

Claudius Feger

Arthur R Zingher

Alphonso Philip Lanzetta

Teresita Ordonez Graham

Caroline A Kovac

Charles H Wilson

Helen L Yeh

John J Liutkus

Nelson R Tanner

Sampath Purushothaman

David Lee Rath

Alfred Viehbeck

Stephen L Buchwalter

Martin J Goldberg

Raymond R Horton

Stephen L Tisdale

Ismail C Noyan

William D Brewer

Edward John Yarmchuk

James M Harper

Mitchell S Cohen

Derek Brian Dove

Michael Frank Cina

Modest M Oprysko

Christoph S Harder

Harry R Bickford

Peter D Hoh

George E Keefe

Greg Costrini

Michael R Scheuermann

John J Glenning

Walter P Pawlowski

Mark J Schadt

Jack M McCreary

Kenneth Paul Jackson

Robert E Schwall

Darbha Suryanarayana

Charles J Kircher

Douglas J Hall

Irving Ames

William A Donson

Arsam Antreasyan

Wilhelm Anacker

Myra N Boenke

A flex or TAB product suitable for chip carrier applications wherein the flex reliability problems caused by copper dendrite growth and lead bending during power and thermal cycling are reduced by application of special coatings to lead areas of the flex tape.

Coated means for connecting a chip and a card

Method of applying flex tape protective coating onto a flex product

Certain organic polymeric materials are capable of reversibly accepting or donating electrons from a reducing entity. The redox sites in the polymer accept electrons and, as a result, a change in the properties of the polymer occurs. This change is useful in modifying or etching the polymeric material. The material can be modified by incorporation of metallic seeds into the material at a controlled depth. The seeds are incorporated by interaction of cations of the metals with the redox sites in the polymer, which cause the reduction of the cations to form the neutral metallic seeds. Subsequent exposure of the polymeric material containing the seeds to an electroless bath causes further deposition of metal having the desirable characteristic of good adhesion to the polymeric material. Etching of the polymeric material can be carried out as a result of an increase in solubility of the polymer in aprotic solvents when its redox sites have accepted electrons. The increased solubility allows openings to be etched in certain areas of the polymeric material that have been reduced, leaving other areas unchanged.

Method for bonding two surfaces together

A multi-chip module having very high density interconnect structures and a technique for making it, where all of the chips have their active device surfaces in a common plane. The chips are placed face down on an adjacent adhesive layer located on a substrate, which is preferably a flexible material. A conformal material is deposited over the backsides of the chips and in the spaces between the chips. A ground plane or metallic shield can then be formed over the conformal layer, if desired. The structure is then turned over and the glass layer on which the substrate is located is removed. Access vias are made through the substrate to the chip I/O's, and metallization provided to the chips. Interconnect metallization is then provided to complete the multi-chip module. In one embodiment, the substrate on which the chips are first supported is the first level of insulation above the active device surfaces of the chips and also ensures that the active device surfaces are in a common plane.

Method of forming multi-chip module with high density interconnections

The present invention relates to an improved flex (or TAB) product suitable for silicon carrier or other types of chip carrier applications, wherein the flex reliability problems caused for example by Cu thermal cycling are substantially reduced or eliminated. More particularly, the invention embodies a number of coatings for use in such products and diverse methods of making and using same.

Flex tape protective coating

A protection configuration for a semiconductor ridge waveguide laser structure is disclosed wherein layers of protective metal in the form of walls, is applied on each side of the ridge element of the ridged layer of the laser structure. The laser structure is then bonded to a mounting plate in a junction side down orientation by solder or a junction side up orientation by wire bonding. The metal layer may be composed of gold.

Waveguide ridge laser device with improved mounting and ridge protection

Disclosed is a reworkable circuit .package formed by controlled collapse chip connection ('C4') bonding of integrated circuit chips to circuit cards and boards, and direct chip attachment ('DCA') where an encapsulant is disposed under the chip. The encapsulant offers protection of the C4 connections and a thermal expansion matched to that of the C4 joints. However, most encapsulants interfere with reworkability. The disclosed circuit package overcomes this problem by the provision of a passivating layer of Parylene is reworkable, dry processable, uniformly depositable by vapor phase deposition, forming thin films on facing surfaces at the 3-5 micron film thickness corresponding to the C4 lift-off distance.

Method of fabricating a reworkable module

Certain organic polymeric materials are capable of reversibly accepting or donating electrons from a reducing entity. The redox sites in the polymer accept electrons and, as a result, a change in the properties of the polymer occurs. This change is useful in modifying or etching the polymeric material The material can be modified by incorporation of metallic seeds into the material at a controlled depth. The seeds are incorporated by interaction of cations of the metals with the redox sites in the polymer, which cause the reduction of the cations to form the neutral metallic seeds. Subsequent exposure of the polymeric material containing the seeds to an electroless bath causes further deposition of metal having the desirable characteristic of good adhesion to the polymeric material. Etching of the polymeric material can be carried out as a result of an increase in solubility of the polymer in aprotic solvents when its redox sites have accepted electrons. The increased solubility allows openings to be etched in certain areas of the polymeric material that have been reduced, leaving other areas unchanged.

Method for conditioning an organic polymeric material

The present invention comprises the use of a copper/nickel containing alloy composition or application of a protective nickel alloy coating to copper current-carrying leads to prevent electrolytic migration between tape automated bonding (TAB) package leads.

Composition and coating to prevent current induced electrochemical

Methods and apparatus are set forth for passively and precisely aligning pairs of objects, in particular, microelectronic components such as semiconductor lasers and fibers, utilizing fiducial marks. Additionally, methods and apparatus are set forth for combining passive and active alignment techniques where high degrees of alignment precision are required. Still further, techniques are described for fixing prealigned objects, independent of how the objects are prealigned, to a mounting surface in a manner that maintains the relative (aligned) position of the objects. Further yet, in order to help minimize manufacturing costs with respect to production of, for example, microelectronic assemblies, batch processing techniques are described which utilize the novel alignment procedures contemplated by the invention.

Methods and apparatus for precise alignment of objects

A heat exchanger for cooling an array of electric circuit chips disposed on a common substrate is formed as a flexible sheet of thermally conducting material with upstanding fins for transference of heat from the chips to a coolant flowing through the fins. Pin fins may be employed with air coolant. The sheet may be provided with corrugations set between sites of the chips for improved flexibility to accommodate individual orientations of the chips. The sheet is sufficiently large to cover an array of chips and is thermally joined, as by use of a thermally conductive grease, to the chips. The sheet hermetically seals the chips from contamination by the coolant. For liquid coolant, the heat exchanger may be fabricated of copper with a nickel coating, wherein the copper provides the heat conduction and the nickel protects the copper from a corrosive coolant such as water. In one embodiment of the heat exchanger, the fin thickness, the fin spacing and the sheet thickness are all approximately equal, a typical sheet thickness being approximately two mils. Another embodiment uses air cooling, and uses metal pin fins bonded to a metal sheet which is moderately thin and flexible. Transverse motion between the sheet and the array of chips is introduced concurrently with the application of pressure between the sheet and the chips to reduce the thickness of the layers of grease between the chips and the sheet, thereby to improve thermal conductivity between the heat exchanger and each of the chips.

Flexible finned heat exchanger

The superior thermal conductivity of immersion cooling combined with the service convenience of conduction cooling is provided through the use of unitary thermal transfer replaceable units positioned beneath a refrigeration source. Each unit contains electronic devices in a thermal transfer fluid. The unit construction permits replaceability in service without exposing a central fluid reservoir or opening a refrigerator.

Apparatus for temperature control of electronic devices

A heat exchanger for cooling an array of electric circuit chips disposed on a common substrate is formed as a flexible sheet of thermally conducting material with understanding fins for transference of heat from the chips to a coolant flowing through the fins. Pin fins may be employed with air coolant. The sheet may be provided with corrugations set between sites of the chips for improved flexibility to accommodate individual orientations of the chips. The sheet is sufficiently large to cover an array of chips and is thermally joined, as by use of a thermally conductive grease, to the chips. The sheet hermetically seals the chips from contamination by the coolant. For liquid coolant, the heat exchanger may be fabricated of copper with a nickel coating, wherein the copper provides the heat conduction and the nickel protects the copper from a corrosive coolant such as water. In one embodiment of the heat exchanger, the fin thickness, the fin spacing and the sheet thickness are all approximately equal, a typical sheet thickness being approximately two mils. Another embodiment uses air cooling, and uses metal pin fins bonded to a metal sheet which is moderately thin and flexible. Transverse motion between the sheet and the array of chips is introduced concurrently with the application of pressure between the sheet and the chips to reduce the thickness of the layers of grease between the chips and the sheet, thereby to improve thermal conductivity between the heat exchanger and each of the chips.

This invention employs a carrier upon which a thin conductive film has been applied. The conductive film is of a metallic material which exhibits a surface energy such that it is not readily wetted by solder. A patterned mask is disposed on the conductive film, with the mask having openings which expose selected areas of the conductive film. Solder is deposited in the mask openings and is weakly adherent to the exposed areas of the conductive film. The carrier is then disposed over and in registration with conductive land areas of a circuit carrier, such that the solder in the mask openings is aligned with the land areas of the circuit carrier. Subsequently, the carrier and circuit land areas are brought into contact, heated, the solder bonded to the lands, and the carrier is lifted away for subsequent reuse. In another species of the invention, a thin film layer of solder is directly deposited on and weakly adherent to a flexible base layer. Subsequently, tool means which registers with the areas to be soldered, presses the base layer/solder combination against the areas to be coated with solder, thereby causing the solder to adhere to the underlying circuit configuration.

Precision solder transfer method and means

Growing community of inventors

Beacon, NY, United States of America

Kurt R Grebe