International Business Machines Corporation

Joseph Funari

Joseph G Ameen

Bahgat Ghaleb Sammakia

Russell E Darrow

David W Sissenstein, Jr

Ronald J Moore

Thomas E Kindl

Peter Bakos

Jack A Varcoe

James V Ellerson

Christopher G Angulas

Patrick T Flynn

Randy L Orr

Scott D Reynolds

John A Goldfuss, Jr

Michael John Funari

Randall Joseph Stutzman

Joseph Donald Poole

Pedro A Chalco

William Fred Otto

John R Behun

Richard M Poliak

Nelson P Franchak

Don L Baker

J Robert Young

George C Phillips, Jr

Samuel L Smey

Terence C Godown

Diane L Redpath

George S Kotrch

Mary C Green

The invention relates to a process for attaching a demountable flexible module to a circuit board, and includes the following steps: providing a circuit board having at least one, preferably a plurality, of gold plated metal balls disposed thereon; providing a flexible module having at least one, preferably a plurality, of gold plated vias disposed therein; positioning an elastomer stop over the circuit board; positioning the flexible module over the balls; applying pressure to the flexible module for a time sufficient to form a line contact between the gold plating on the vias and the gold plating on the metal ball of the circuit board, wherein the module is removable without heating the module. The process does not use solder to attach the module to the board, and requires substantially less than 2000 psi, and preferably less than 400 psi, to attach the module which produces little, if any, deformation to the flexible module.

Process for manufacturing boards that can accept a pluggable tab module

Solder interconnection for forming connections between an integrated semiconductor device and a carrier substrate is provided. Located on the carrier substrate are electrodes and located between the electrodes and integrated semiconductor device are solder connections that have a relatively low melting point such that when the device is in operation, the solder connection will liquify thereby permitting expansion compensation between the substrate and semiconductor device.

Interconnection of a carrier substrate and a semiconductor device

The present invention provides multi-layer multi-chip circuit board comprising at least two ATAB carriers having chips thereon, stacked upon each other in a pyramid configuration and attached to a substrate, thus reducing the required area on the substrate for mounting components to form a circuit board.

Multi-layer-multi-chip pyramid and circuit board structure and method of

The present invention relates to a circuitized board having removable flexible modules disposed thereon. The flexible modules are mechanically and electrically connected to the board to provide an apertured connect, yet may be easily removed without using heat. The invention also relates to a circuit package including a substrate and a flexible module. The substrate includes a circuit board, a plurality of pads affixed to the circuit board, and a plurality of gold plated metal balls affixed atop the pads. The flexible module includes a flexible dielectric member and gold plated vias disposed in the flexible dielectric member wherein at least some of the vias are positioned over the metal balls so that a line contact is made between the vias and the metal balls.

Circuit boards that can accept a pluggable tab module that can be

Multi-layer, multi-chip pyramid and circuit board structure

A laser head for simultaneously attaching solder balls to a carrier has at least one solder tip, with the number of solder tips being equal to the number of solder balls to be attached to the carrier. Each solder tip is heated by an optical fiber in thermal contact with the tip at one end of the fiber and coupled to a laser, preferably operating in the infrared wavelength range, at the other end of the fiber via a multiplexer coupling device. A spring is used in association with each solder tip to bias each solder tip to hold the carrier in contact with the solder balls. The tip absorbs the radiant energy as it exits the optical fiber, and the tip is heated. The laser and multiplexer permit precise control over the heat imparted to the tip, which in turn permits control of the amount of the solder ball that is reflowed.

Method and apparatus for soldering with a multiple tip and associated

A flexible circuit member including a circuitized substrate of a dielectric material having a plurality of apertures therein. Located within and/or bridging selected ones of the apertures are electrical conductors, the conductors having a solder member secured thereto. A frame is also used, the circuitized substrate being secured thereto.

Flexible circuit member

An electronic package which includes a rigid first substrate (e.g., ceramic) having a plurality of conductive pins spacedly located therein. These pins each include one end portion extending below an undersurface of the substrate for positioning and electrically coupling within a second substrate (e.g., printed circuit board), while also including an opposite end portion which projects from an opposite, upper surface of the first substrate. These upwardly projecting end portions are designed for accommodating, in stacked orientation, a plurality of thin film, flexible circuitized substrates thereon, each of these substrates being electrically coupled to a respective pin, if desired, using a solder composition. In one example of the invention, solder hierarchy for various solders is used, one solder being used to connect the substrates and respective pins, and a second solder (having a higher melting point and different composition from the first solder) used to connect the semiconductor devices (chips) of the flexible circuitized substrates to the conductive circuitry of the substrates. Hydrogen is preferably used to effect solder reflow for the solder which couples the flexible substrates to the respective pins. In an alternate embodiment, the flexible circuitized substrates may include at least two separate conductive layers as part thereof.

Multilayered flexible circuit package

A method of bonding a flexible circuitized substrate to a circuitized substrate (e.g., printed circuit board) to interconnect selected circuitry of both substrates using solder. Solder paste is applied over conductive pads on the circuitized substrate and organic dewetting material (e.g., epoxy coating) adjacent thereto. The flexible substrate, having conductors located within and/or traversing an aperture in the flexible substrate's dielectric, is positioned above the solder paste and heat is applied (e.g., in an oven). The paste, dewetting from the organic material, 'balls up' and substantially surrounds a solder member (ball) attached to a bridging portion of the flexible substrate's conductor, thereby connecting both substrates. A frame member may be used to align the flexible substrate, both during solder member attachment thereto, as well as for aligning the flexible substrate having solder members attached, to the respective solder paste locations on the lower substrate.

Method for bonding flexible circuit to circuitized substrate to provide

Mutlilayered flexible circuit package

An apparatus for bonding a semiconductor device onto a substrate (e.g., a printed circuit board) such that solder elements on the device are connected, respectively, to circuit elements on the substrate. The solder elements are heated by passing hot gas onto an opposing surface of the device such that, by heat transference, the solder elements become partially molten to form the desired connections. Pressure is also applied onto the device during this formation to assure planarity at the connection sites. Following formation, cooling of the connections is accomplished. By directing heated gas onto only the semiconductor device and not onto the solder element-circuit member locations (and thus onto the substrate), direct semiconductor device bonding to lower melting point temperature substrates (e.g., those circuit boards containing fiberglass reinforced epoxy resin as a dielectric) may be achieved.

Apparatus for soldering a semiconductor device to a circuitized substrate

A method of precisely depositing accurately defined quantities of solder onto high density circuit patterns on a substrate without use of a solder mask or the like wherein solder paste is originally deposited within a precisely defined transfer member (e.g., graphite block having holes drilled therein), the transfer member then being aligned relative to the respective circuitry such that when both block and substrate are heated, solder flow and deposition will occur without the use of a solder mask or the like. Following deposition, a second circuit member (e.g., flexible circuit) may be electrically coupled to the substrate's conductors, the deposited solder providing the coupling medium. Hydrogen gas may be used during the heating of the paste and also during the soldering of the flexible circuit to the substrate.

Method of applying solder

A method for bonding a semiconductor device onto a substrate (e.g., a printed circuit board) such that solder elements on the device are connected, respectively, to circuit elements on the substrate. The solder elements are heated by passing hot gas onto an opposing surface of the device such that, by heat transference, the solder elements become partially molten to form the desired connections. Pressure is also applied onto the device during this formation to assure planarity at the connection sites. Following formation, cooling of the connections is accomplished. By directing heated gas onto only the semiconductor device and not onto the solder element-circuit member locations (and thus onto the substrate), direct semiconductor device bonding to lower melting point temperature substrates (e.g., those circuit boards containing fiberglass reinforced epoxy resin as a dielectric) may be achieved.

Method for soldering a semiconductor device to a circuitized substrate

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Vestal, NY, United States of America

Joseph Funari