International Business Machines Corporation

John Gillette Davis

Joseph Donald Poole

Michael A Gaynes

Mark Vincent Pierson

Amit Kumar Sarkhel

Ajit Kumar Trivedi

Christian Robert Le Coz

Alan Harris Crudo

Michael Camillo Weller

Allen Thomas Mays

Joseph Michael Kielbasa

Kris Allan Slesinger

Richard Joseph Noreika

James Westcott Heater

Kris Allen Slesinger

Curved surfaces of a preform of thermoplastic adhesive provide improved regulation of heating and exclusion of gas as surfaces to be bonded are heated and pressed against the thermoplastic adhesive preform. Particulate or filamentary materials can be added to the thermoplastic adhesive for adjustment of coefficient of thermal expansion or further increase of heat transfer through the adhesive or both. The preform is preferably fabricated by molding, preferably in combination with die-cutting of a preform of desired volume from a web of approximately the same thickness as the completed bond.

Thermoplastic adhesive preform for heat sink attachment

A method for applying pressure to circuit components during a manufacturing operation. The method utilizes a plurality of compressed air pressure cylinders which are supported on a plurality of horizontal arms along different axes over a circuit board. Compressed air is supplied simultaneously to each of the cylinders, and the cylinders force the component onto a bonding position on the circuit board. The method permits heat sinks to be pressed against components located on the circuit board to bond the heat sinks to the components.

Universal tool for uniformly applying a force to a plurality of components on a circuit board

A method of mounting a component on a substrate includes applying a conductive adhesive on a contact pad joined to a substrate, aligning a component with the substrate such that at least one lead of the component is juxtaposed with the conductive adhesive, performing a partial cure of the conductive adhesive, testing performance of the component, and performing a full cure of the conductive adhesive. Another method includes the additional steps of applying a tacky film to the substrate and juxtaposing the component with the tacky film. When the testing in either embodiment shows a defective or misaligned component, the component may be replaced or repositioned by cold separation of the at least one component lead from the partially cured conductive adhesive. Optionally, additional conductive adhesive may be applied, when needed, before replacement or repositioning of a component. A composition for mounting a component on a circuit board includes a conductive adhesive screened on a contact pad, the conductive adhesive being partially cured, wherein the composition allows cold separation of the component from the substrate and may be fully cured by heat exposure. An apparatus is also provided including a component, a substrate, and a means for temporarily mounting and electrically connecting the component on the substrate.

Method and composition for mounting an electronic component and device formed therewith

A transfer fluxing apparatus is provided. The apparatus is a flux reservoir for holding flux, a compliant pad attached to an opening in the flux reservoir and a means for controlling deposition of flux onto the compliant pad. The apparatus can be attached to an automated component placement machine. In the preferred embodiment of the invention, the control means is a valve located within the flux reservoir. The valve is opened by applying pressure to a plunger that extends through the compliant pad. When the plunger is pressed, the valve opens, and flux falls onto the compliant pad. Flux then passes through the pad to a component placement site. A method for automated fluxing and to component placement also is provided.

Transfer fluxing method and apparatus for component placement on substrate

A method and apparatus for efficiently repairing or reworking a printed circuit board having a solder ball grid array thereon efficiently and at minimum cost includes the steps of drilling out a plated-through hole to sever electrical connections between a ball grid array pad on one surface of the printed circuit board and internal circuits and circuits on an opposite surface of the printed circuit board; inserting a pin having an insulated sleeve surrounding a portion thereof into the drilled-out hole, the pin having attached to one end a wire for attachment to the ball grid array on one surface of the printed circuit board and a post at the other end of the pin for attachment of a wire to the post; the pin having a stop along its length to control vertical positioning of the pin in the drilled-out hole, the pin referred to as a via replacement (VR) pin. Alternately, after the plated through hole is drilled out, an insulated wire may be inserted into the hole with insulation removed from the length of the wire which extends beyond one surface of the printed circuit board. The bare length of wire is bent parallel to the surface of the printed circuit board and attached thereto by a solder reflow process. In a dog bone configuration, the wire is formed around a pad on the surface of the printed circuit board which receives the solder ball.

Apparatus and method for printed circuit board repair

A process for making a removably interlockable connector assembly that includes a first connector having a head on a mesa and a second connector having an opening that receives the head on the first connector. The head on the mesa of the first connector and the material defining the opening in the second connector are flexible and sized, so that the head on the mesa of the first connector and the material defining the opening in the second connector flex as the head on the mesa of the first connector is inserted into the opening in the second connector. The head on the mesa of the first connector is formed by selectively etching portions of a first pad layer through openings in an etch resistant layer.

Process of manufacturing a removably interlockable assembly

Apparatus for printed circuit board repair

A method and device for attaching a module having a ball grid array or column grid array of solder material thereon arranged in a given pattern or footprint to a substrate having an array of connector pads arranged in the same pattern is provided. A preformed alignment device has an array of through holes therein aligned in the same pattern or footprint as the ball grid array or column pattern on the module and the pattern of contact pads on the substrate. The through holes in the preform are filled with a solder material which can be either a solder paste or a solid solder or with a curable conductive adhesive. The solder preferably is a lead-tin eutectic, but in any event has a melting point of less than about 240&deg; C. and in the case of the conduction adhesive, will cure below about 240&deg; C. The preform with the filled through holes is interposed between the module and the substrate with the material in the holes in contact with the solder balls or columns and the contact pads. Heat is applied to reflow the solder or cure the adhesive in the holes to join the module to the substrate. Depending upon the composition of the solder of the balls or columns, they might or might not melt. In the case of solid solder, thin films of flux material can be applied to opposite faces of the preform to prevent the solder from dislodging therefrom and to act as a flux when the solder is reflowed.

Method and apparatus for soldering ball grid array modules to substrates

A removably interlockable connector assembly and process for making the assembly that include a first connector having a head on a mesa and a second connector having an opening that receives the head on the first connector. The head on the first connector and the material defining the opening in the second connector are flexible and sized, so that the head on the first connector and the material defining the opening in the second connector flex as the head on the first connector is inserted into the opening in the second connector.

Removable interlockable first and second connectors having engaging flexible members and process of making same

A multiple force tool for applying pressure to circuit components during a manufacturing operation. A plurality of compressed air pressure cylinders are supported on a plurality of horizontal arms over a circuit board. A pressure foot of each compressed air pressure cylinder is extendable when an air controller foot switch is depressed. Positioning of each of the cylinders is afforded along two axes, so that the cylinders may be positioned over components which are to be pressed against the circuit board. Heat sinks may be pressed against components located on the circuit board to bond the heat sinks to the components.

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Charlotte, NC, United States of America

John Gillette Davis