Lsi Logic Corporation

Fairchild Camera and Instrument Corp.

Signetics

Mark R Schneider

Michael D Rostoker

Joseph H Joroski

Nicholas F Pasch

Abraham Fong Yee

Edwin M Fulcher

Janet Kirkland

Michael J Steidl

William C Schneider

Chok J Chia

Jon M Long

Dexin Liang

Robert T Trabucco

Sadanand R Patil

Ernest J Funk

Larry D Wickwar

Floyd F Oliver

Jack C Lane

Alfred S Jankowski

Edward F Duffek

William L Lehner

Len Molloy

Susan A Oliver

Method of cooling electronic systems an semiconductor devices as well as an electronic system and a semiconductor device with heat dissipating elements. The method includes the steps of providing an electronic system or a semiconductor device with a heat sink including at least a first element having a generally flat shape with a shoulder projecting from one generally flat surface, and configured to thermally engage similar elements. In one embodiment, a first and a second heat sink element are provided, with one of the first and second elements having a protrusion and the other of the first and second elements defining a depression configured to receive and retain said protrusion. Alternatively, the first and second elements may be bonded together with a thermally conductive adhesive.

Method of assembling a heat sink assembly

A stackable heat sink assembly is formed by press-fit assembly of two or more identical fin layers. Each fin layer is formed using powdered metallurgy and has a button-like projection extending from its bottom surface and a recess opening in its top surface. The button-like projection and recess opening are sized and shaped such that an interference fit is formed when the button-like projection of one fin layer is pressed into the recess of another fin layer. The use of an adaptor to increase or decrease the effective size of the button-like projection of the bottommost fin layer is described. Relieving gases that may be entrapped in the recess during assembly is described. Circular, elliptical and polygonal shapes (outlines) for the fin layers are described.

Stackable heatsink structures for semiconductor devices

A semiconductor die is mounted to a die receiving area, which is defined by inner ends of conductive leads to which the die is connected. The die is temporarily retained in a substantially fixed position relative to the die receiving area by various techniques for the purpose of permitting bond wires to be attached between the conductive leads and the die. Preferred techniques include employing a mechanical chuck, dispensing an adhesive between the die and its die receiving area, and forming an ultrasonic bond between the die and the die receiving area. Once electrical connections between the die and the conductive lines are formed, the die need not be retained in a fixed position, as the electrical connections will provide sufficient support for the die. Accordingly, conventional die attach techniques, which expose the semiconductor die to substantially elevated temperatures, are avoided. Further, dies so mounted, which are not firmly anchored in accordance with conventional the attach techniques, are not subjected to mechanical stresses resulting from a difference in die thermal expansion between the die and its die receiving area.

Technique for mounting a semiconductor die

An integrated circuit package having a die supported on a ball grid array substrate and wire bonds electrically connecting the die to the substrate. Supported on the substrate is a lock ring having a threaded opening encircling the die. Encapsulant covers the die and the wire bonds and adheres the lock ring to the substrate. A heat sink having a threaded portion can be threaded into the lock ring into an operative cooling position relative to the die and subsequently to an unthreaded removed position. When in the latter position, a repair station can be positioned over the package and the solder balls are accessible for hot gas melting thereof for removal (or replacement) of the package from the underlying motherboard.

Ball grid array with inexpensive threaded secure locking mechanism to

Apparatus for use in cooling an integrated circuit structure. The apparatus includes a heat sink having a first portion configured for thermal engagement with an integrated circuit device and a second portion configured for the dissipation of heat into an ambient fluid, such as air. The heat sink is made from a powdered metal which, in one preferred embodiment, includes copper. The heat sink may be formed from the plurality of discrete layers, each layer having a button projecting from one surface, and a depression formed in an opposing surface. The depression is configured to receive a projecting button portion from another layer. In an alternative embodiment the heat sink includes a plurality of plugs projecting from the generally flat surface.

Powder metal heat sink for integrated circuit devices

A method and apparatus for dissipating heat from a semiconductor device. A heat sink embodying the method includes an exterior surface contoured to better facilitate heat dissipation and/or direct a flow of air or fluid over the heat sink. In one embodiment, the heat sink includes a heat sink layer formed from a powdered metal. In another embodiment, the heat sink layer is contoured with a selected combination of bumps, indentations and holes. In yet another embodiment, the heat sink includes a stack of such heat sink layers which are mechanical; interfitted and thermally coupled.

Powdered metal heat sink with increased surface area

A method and apparatus for dissipating heat from a semiconductor device. A heat sink embodying the method includes an exterior surface contoured to better facilitate heat dissipation and/or direct a flow of air or fluid over the heat sink. In one embodiment, the heat sink includes a heat sink layer formed from a powdered metal. In another embodiment, the heat sink layer is contoured with a selected combination of bumps, indentations and holes. In yet another embodiment, the heat sink includes a stack of such heat sink layers which are mechanically interfitted and thermally coupled.

Method of manufacturing powdered metal heat sinks having increased

Ball grid array package with inexpensive threaded secure locking

An electronic system having improved thermal transfer from a semiconductor die in a semiconductor device assembly (package) by at least partially filling a cavity in the package with a thermally conductive fluid, immersing a heat collecting portion of a heat pipe assembly into the fluid, and sealing the cavity. In order that the thermally conductive fluid does not chemically attack the die or its electrical connections, the die and connections can be completely covered with an encapsulating coating of an inorganic dielectric material, such as silicon dioxide, by any of a variety of techniques. The heat pipe provides highly efficient heat transfer from within the package to an external heat sink by means of an evaporation-condensation cooling cycle. The optional dielectric coating over the die permits selection of the thermally conductive fluid from a wider range of fluids by isolating the die and its electrical connections from direct contact with the fluid. In another embodiment, an absorptive wick is disposed within the package to transport condensed coolant to close proximity with the die. A heat pipe and wick may be employed in combination, and the heat pipe may have hollow fins, and the wick may extend into the fins (as well as into the package cavity). The use of a wick improves the thermal characteristics of the packaged device irrespective of its physical orientation.

Electronic system having fluid-filled and gas-filled thermal cooling of

Electronic systems utilizing a plurality of integrated circuit packages having a stackable heat sink assembly is formed by press-fit assembly of two or more identical fin layers. Each fin layer is formed using powdered metallurgy and has a button-like projection extending from its bottom surface and a recess opening in its top surface. The button-like projection and recess opening are sized and shaped such that an interference fit is formed when the buttonlike projection of one fin layer is pressed into the recess of another fin layer. The use of an adaptor to increase or decrease the effective size of the button-like projection of the bottom-most fin layer is described. Relieving gases that may be entrapped in the recess during assembly is described. Circular, elliptical and polygonal shapes (outlines) for the fin layers are described.

System having stackable heat sink structures

System for producing a plurality of semiconductor device assemblies utilizing a grid array of conductive epoxy for connecting them to an electronic system. Conductive epoxy is screen printed in a desired pattern onto a printed wire board of the semiconductor device assembly. The conductive epoxy is B-staged by heating in an oven. The semiconductor device assembly is then placed onto a system printed circuit board wherein the B-staged conductive epoxy is further cured by heat and effectively makes mechanical and electrical connections between the semiconductor device assembly and the system printed circuit board.

System for fabricating conductive epoxy grid array semiconductor packages

A ball bump grid array package includes dies on one surface of a printed wiring board (PWB) and an array of ball bumps on the other surface of the PWB. The die is interconnected with the ball bumps by bond wires, traces on the one surface of the PWB, vias through the PWB and traces on the other surface of the PWB. Various die encapsulation schemes are discussed. The PWB is formed of FR4, BT, teflon or polyimide, or ceramic materials. The die may be connected to the traces on the one surface of the PWB with solder balls, rather than with bond wires. Two or more dies may be disposed on the one surface of the PWB, within the plastic molded body. The ball bumps on the other surface of the PWB may be arranged in a multiple grid pitch array--ball bumps within a central area being on a first pitch, and ball bumps without the central area being on a second pitch which is a multiple of the first pitch.

Method of assembling ball bump grid array semiconductor packages

Process for manufacturing a high interconnection density, fine-line, superconductive printed leadframes using thick-film screen-printing techniques, or other printing techniques. Generally, a superconductive leadframe pattern is printed on a backing substrate. Once the pattern is cured, the backing substrate, or portions thereof can be removed. The backing substrate can be a 'fish paper' substrate treated with a release agent, or other substrate material which can be dissolved away, etched away, or otherwise removed. Portions of the backing substrate can be used to provide mechanical integrity for the leadframe. The leadframe fingers can be printed using a superconductive paste or a superconductive precursor paste which is subsequently treated to exhibit superconductivity.

Printable superconductive leadframes for semiconductor device assembly

Method of cooling electronic systems and semiconductor devices as well as an electronic system and a semiconductor device with heat dissipating elements. The method includes the steps of providing an electronic system or a semiconductor device with a heat sink including at least a first element having a generally flat shape with a shoulder projecting from one generally flat surface, and configured to thermally engage similar elements. In one embodiment, a first and a second heat sink element are provided, with one of the first and second elements having a protrusion and the other of the first and second elements defining a depression configured to receive and retain said protrusion. Alternatively, the first and second elements may be bonded together with a thermally conductive adhesive.

Growing community of inventors

San Jose, CA, United States of America

Mark R Schneider