International Business Machines Corporation

Hussain Shaukatullah

Michael A Gaynes

Thomas M Culnane

Ping Kwong Seto

Steven Joel Diffenderfer

Glenn David Gilda

Frank E Andros

Wayne R Storr

Don L Baker

Terrence A Quinn

A structure for removably attaching a heat sink to an electronic package. At least one heat sink engaging member engages a surface of the heat sink opposite a surface of the heat sink engaging the electronic package. At least two heat sink retaining clips extend from opposite sides of the at least one heat sink engaging member. Each retaining clip includes a first arm for extending past a side of the heat sink and a portion of the electronic package and a second arm extending from the first member for engaging the electronic package.

Structure for removably attaching a heat sink to surface mount packages

A method of making an electronic package. The method includes the step providing a leadframe of a single layer of material. The leadframe includes a semiconductor chip support, a plurality of signal leads, and a common ground portion substantially surrounding the chip support portion. A semiconductor chip having a plurality of signal sites and a plurality of ground sites is positioned on the semiconductor chip support of the leadframe. Selected ones of the signal sites of the semiconductor chip are selectively electrically connected to respective ones of the signal leads of the lead frame and selective ones of the ground sites of the semiconductor chip are selectively electrically connected to the common ground portion of the leadframe. Each of the signal leads of the leadframe are electrically isolated from each other and from the common ground portion of the leadframe.

Single layer leadframe design with groundplane capability

An aluminum or copper heat sink is attached to a ceramic cap or exposed semiconductor chip using flexible-epoxy to provide improved thermal performance. The aluminum may be coated by anodizing or chromate conversion or the copper may be coated with nickel. Such structures are especially useful for CQFP, CBGA, CCGA, CPGA, TBGA, PBGA, DCAM, MCM-L, single layer ceramic, and other chip carrier packages as well as for flip chip attachment to flexible or rigid organic circuit boards. These adhesive materials withstand thermal cycle tests of 0.degree. to 100.degree. C. for 1,500 cycles, -25.degree. to 125.degree. C. for 400 cycles, and -40.degree. to 140.degree. C. for 300 cycles; and withstand continuous exposure at 130.degree. C. for 1000 hours without loss of strength. Flexible-epoxies have a modulus of elasticity below 100,000 psi and a glass transition temperature below 250.degree. C., are much stronger than typical silicone adhesives, and do not contaminate the module or circuit board with silicone. The flexible epoxy may contain a material having a low coefficient of thermal expansion (CTE) in order to provide a CTE between that of the silicon die and the metal of the heat sink.

Apparatus for attaching heat sinks directly to chip carrier modules

An aluminum or copper heat sink is attached to a ceramic cap or exposed semiconductor chip using flexible-epoxy to provide improved thermal performance. The aluminum may be coated by anodizing or chromate conversion or the copper may be coated with nickel. Such structures are especilly useful for CQFP, CBGA, CCGA, CPGA, TBGA, PBGA, DCAM, MCM-L, single layer ceramic, and other chip carrier packages as well as for flip chip attachment to flexible or rigid organic circuit boards. These adhesive materials withstand thermal cycle tests of 0.degree. to 100.degree. C. for 1,500 cycles, -25.degree. to 125.degree. C. for 400 cycles, and -40.degree. to 140.degree. C. for 300 cycles; and withstand continuous exposure at 130.degree. C. for 1000 hours without loss of strength. Flexible-epoxies have a modulus of elasticity below 100,000 psi and a glass transition temperature below 25.degree. C., are much stronger than typical silicone adhesives, and do not contaminate the module or circuit board with silicone. The flexible epoxy may contain a material having a low coefficient of thermal expansion (CTE) in order to provide a CTE between that of the silicon die and the metal of the heat sink.

Chip carrier modules with heat sinks attached by flexible-epoxy

Method for attaching heat sinks directly to chip carrier modules using

A method of making an electronic package including providing a leadframe of a single layer of material. The leadframe includes a semiconductor device support, a plurality of signal leads, and a common ground portion surrounding the device support portion. A semiconductor device having a plurality of signal sites and a plurality of ground sites is positioned on the semiconductor device support of the leadframe. Selected ones of the signal sites are connected to respective ones of the signal leads. Selective ones of the ground sites are connected to the common ground portion of the leadframe. Each of the signal leads are electrically isolated from each other and from the common ground portion of the leadframe.

Method for making single layer leadframe having groundplane capability

An electronic package including a leadframe that includes a single layer of an electrically conducting material, a semiconductor chip support, a common ground portion surrounding the semiconductor chip support and electrically connected thereto, a plurality of signal leads electrically isolated from each other and from the common ground portion, and a plurality of ground leads electrically connected to the common ground portion. A semiconductor chip including a plurality of signal sites and a plurality of ground sites is mounted on the semiconductor chip support of the leadframe. A plurality of electrical connections are provided between selected ones of the signal sites to respective ones of the signal leads and between selected ones of the ground sites to respective ones of the ground leads. A protective enclosure is provided substantially about the semiconductor device, the semiconductor chip support, the common ground portion of the leadframe, and at least a portion of the signal leads.

A portable thermocouple template is built to have one or more separate thermocouple beads fixedly attached at predetermined locations on a thin insulator sheet, with appropriate tape or the like for holding each thermocouple and its pair of connector wires in position on the sheet. The template is mountable between interconnected electronic components, such as on the pin side of a multichip module, in order to monitor the temperature of the adjacent components under actual operating conditions. After the test is completed and the temperature data is recorded and/or displayed on a data logger, the template and related assembly wires are removed and stored until such time as the template is needed for mounting again in order for additional thermal tests to be conducted.

Growing community of inventors

Endwell, NY, United States of America

Hussain Shaukatullah