Showing papers on "Heat sink published in 1990"

Terrestrial concentrator solar cell module

Abstract: Solar cells, particularly GaAs/GaSb tandem solar cells, are mechanically and electrically connected in the form of a string using a flexible circuit tape and mounted in optical alignment with solar energy concentrators in a module. A heat spreader body is attached to each cell unit as part of a heat sink and the cells are precisely positioned to provide optical alignment. The flexible circuit tape is formed by conductive strips sandwiched between layers of polymer dielectric tape and provided with tabs at predefined holes in the tape for bonding to current carrying surfaces of concentrated sunlight tandem solar cell units.

Method of sealing semiconductor device with resin by pressing a lead frame to a heat sink using an upper mold pressure member

Abstract: A method of sealing a semiconductor device with resin includes the steps of coupling the tie bar of a lead frame to a heat sink; die bonding a semiconductor chip to the surface of the heat sink; wire bonding and electrically connecting the semiconductor chip to leads of the lead frame; placing the heat sink on the bottom surface of a cavity of a lower mold, putting an upper mold on the lower mold, and pressing down the coupling portion between the heat sink and lead frame toward the bottom surface by using a pressure member mounted on the upper mold; and injecting melted resin within the cavity defined by the upper and lower molds, and hardening the resin.

Conformable pad with thermally conductive additive for heat dissipation

Abstract: A conformable, gel-like pad, preferably of silicone, with a thermally conductive additive conducts heat away from a packaged electronic power device with which it is in contact. Formed by adding particles of a thermally conductive material such as aluminum powder, nickel, aluminum oxide, iron oxide, beryllium oxide, silver, etc., to a mixture of silicone resins and curing agents poured into a mold, the molded pad can be formed to accommodate virtually any geometry and size of electronic component to provide a custom-fit at little cost. A thin, solid sheet of a thermally conductive metal such as aluminum positioned in contact with a surface of the conformable pad further increases heat removal. Another embodiment contemplates a metallic foil disposed in contact with a surface of or within the conformable pad and extending therefrom which can be coupled to a heat sink or to neutral ground potential for radiation shielding. A metallic radiation shield box may be used as a mold for forming the conformable pad and to form a combination EMI/RFI radiation shield and heat transfer device for an electronic component disposed within the box and in contact with the conformable pad.

Advances in thermodynamics

Abstract: This book covers the following: heat transfer during freezing of biological materials; condensation of azeotropic and nonazeotropic binary vapor mixtures; interface in film condensation; thermal phenomena in High-T{sub c} thin-film superconductors; a comparative analysis of multiphase transport models in porous media; a comparison of convective heat transfer in packed beds and granular flows; and microscales and scales in heat transfer.

Geothermal heat transfer system

Abstract: A geothermal system for conditioning air in an enclosed space by transferring heat between the air and a heat exchange liquid which is circulated through a line buried in the earth. The line transfers heat between the earth and the heat exchange liquid circulating through the line. The line is constructed to facilitate the expansion and contraction of the line with changes in temperature and to facilitate the transfer of heat between heat exchange liquid in the line and the earth without causing ice to form around the line.

Modular package for cooling a laser diode array

Abstract: A laser diode array is disclosed that includes a plurality of planar packages and active cooling. The laser diode array may be operated in a long duty cycle, or in continuous operation. A laser diode bar and a microchannel heat sink are thermally coupled in a compact, thin planar package having the laser diode bar located proximate to one edge. In an array, a number of such thin planar packages are secured together in a stacked configuration, in close proximity so that the laser diodes are spaced closely. The cooling means includes a microchannel heat sink that is attached proximate to the laser bar so that it absorbs heat generated by laser operation. To provide the coolant to the microchannels, each thin planar package comprises a thin inlet manifold and a thin outlet manifold connected to an inlet corridor and an outlet corridor. The inlet corridor comprises a hole extending through each of the packages in the array, and the outlet corridor comprises a hole extending through each of the packages in the array. The inlet and outlet corridors are connected to a conventional coolant circulation system. The laser diode array with active cooling has application as an optical pump for high power solid state lasers. Further, it can be incorporated in equipment such as communications devices and active sensors, and in military and space applications, and it can be useful in applications having space constraints and energy limitations.

A method for the measurement of the thermal, dielectric, and pyroelectric properties of thin pyroelectric films and their applications for integrated heat sensors

Abstract: A method is described that enables the simultaneous or consecutive determination of the specific heat, the thermal diffusivity, the dielectric constant, and the pyroelectric coefficient of thin pyroelectric films. The sample is heated by the absorption of intensity modulated light at one surface. The pyroelectric current and the transient temperatures of the sample surfaces are recorded as a function of the modulation frequency of the chopped light. The transient temperature recording is performed via thin‐film bolometers. Analysis procedures for the determination of the specific heat, the thermal diffusivity, and the spatially varying pyroelectric coefficient are introduced and discussed. A simulation of the performance of integrated pyroelectric ir sensors on silicon chips is performed by a coupling of the pyroelectric material to a heat sink. It is shown that the response of pyroelectric ir sensors integrated on silicon chips is influenced by heat wave interference effects. Experimental results are giv...

Arrangement for electronic circuit module

Abstract: Electronic circuit modules (10; 100; 400) have connector (11; 111; 411) with through pins (14, 114; 414) and a metal ground path (17) embedded therein which fit within a recess (24; 124; 424) formed by a heat sink (18; 118; 418) having a central plate portion (19) surrounded by metallic cooling fins (23). A polyimide insulating circuit base film (26; 126; 500) has conductor paths (27) and circuit components (30) on at least a top surface (28) thereof with a bottom surface (31) mounted to the top surface (21) of the heat sink plate portion (19). The connector through pins are electrically connected to the conductor paths on the polyimide base film and a cover (33;133) together with the heat sink forms an internal cavity (34; 134) for protection of the components. This structure provides a compact configuration and lower manufacturing costs for a circuit module, permits reducing RF radiation and absorption problems and permits reducing resistive connections between the through pins and the components. Also implemented are high frequency bypass capacitive networks (18, 222; 118, 325) associated with each of the conductive through pins.

Thermally enhanced semiconductor device utilizing a vacuum to ultimately enhance thermal dissipation

Abstract: A semiconductor device having a heat sink is provided in which an opening through the heat sink enables a vacuum source to be applied to a semiconductor die mounted surface. In one form, a semiconductor die is attached to a mounting surface of a leadframe. The leadframe also has a plurality of leads which are electrically coupled to the semiconductor die. The semiconductor die and portions of the leads encapsulated in a package body. Also incorporated in the package body is a heat sink. The heat sink has an opening which extends through the heat sink and exposes a portion of the mounting surface of the leadframe. The opening is used to apply a vacuum to the mounting surface during the formation of the package body so that the mounting surface and heat sink are held in close proximity. The closeness provides a good thermal conduction path from the semiconductor die to the ambient, thereby enhancing the thermal dissipation properties of the device.

Thermal energy storage heat exchanger

Abstract: A modified tube and shell heat exchanger is comprised of a tube of heat sink material having micro heat pipes extending outward into the volume between the tube and shell to enable the rapid and efficient transfer and storage of thermal energy into the heat sink from a liquid or gas circulated through the volume. Several embodiments of the invention include modifications to the heat pipes. An alternative embodiment reverses the location of the heat sink to fill the volume between the shell and tube, adapting the tube for fluid flow, and orients heat pipes inward into the tubes and outward beyond the shell in various arrangements. The heat exchanger is further shown embodied in a system for the removal, transfer, storage and dissipation of thermal energy from a heat source for ground-based and space-based applications.

Space suit cooling apparatus

Abstract: Apparatus for removing heat energy of a cooling medium passing from a space suit liquid cooling garment includes a heat sink assembly for absorbing and rejecting the heat energy and a heat transfer means for transferring the heat energy of the cooling medium to the heat sink assembly. The heat transfer means, which is comprised of an array of thermoelectric modules, regulates the quantity of heat energy transferred from the cooling medium to the heat sink assembly. The heat sink assembly includes a material which isothermally changes phase while absorbing heat energy.

Air jet impingement on miniature pin-fin heat sinks for cooling electronic components

Abstract: An air-jet impingement cooling method combined with a miniature pin-fin heat sink provides equivalent fluid flow to each IC package in a module and achieves a high heat transfer rate per volume. The packaging design is comparable to high-density packaging systems utilizing low-temperature coolant.

Apparatus for cooling circuits

Abstract: An apparatus for cooling circuit modules by use of a thermo-electric device which comprises a series of semiconductor regions and etched copper conductors designed to conduct heat in a specified direction by means of the Peltier Effect. The thermo-electric device is sandwiched between two layers of a polymer based, thermally conductive dielectric such as the dielectric used in the manufacture of Thermal Clad™. The hot layer of Thermal Clad™ (i.e., the layer that receives heat) is laminated directly to a heat sink. The cold layer of Thermal Clad™ is laminated directly to a cold plate which is, in turn, coupled to the circuit module.

Conforming heat sink assembly

Abstract: A conforming heat sink assembly including a heat dispersive element is mounted in spaced relationship to a surface from which heat is to be conducted. A thermal interface is provided for coupling the heat dispersive element to the surface from which heat is to be conducted. The thermal interface includes an elastomeric member which occupies only a portion of a volume defined by mounting the heat dispersive element proximate the surface from which heat is to be conducted. The unoccupied volume allows the elastomeric member to easily conform to the irregular surface from which heat is to be conducted to enhance thermal conductivity from the surface to the heat dispersive member.

High power semiconductor device with integral heat sink

Abstract: A high power semiconductor device with integral heat sink capable of accommodating substantial heat flux on the order of one kw per cm 2 . The integral heat sink is formed on the active surface of the semiconductor and utilizes an AlN thin film of high purity to provide a low thermal impedance heat conductor for removing heat directly from the active semiconductor surface. A microchannel heat sink is formed on the A1N thin film and has a source of cooling fluid flowing through the microchannel heat sink for conducting heat away from the sink. The result is the ability to conduct large heat fluxes away from the intimately contacted heat generating semiconductor surface to the cooling fluid in the microchannel heat sink and thus operate the semiconductor under substantially higher power than has been practical heretofore in a device of such simplicity.

Apparatus for packaging and cooling integrated circuit chips

Abstract: A packaging and cooling assembly for integrated circuit chips includes a base for reception of one or more circuit chips, and a combination heat sink and cover for attachment to the base. The circuit chips are mounted circuit side down on the base, and include flexible lead frames for attachment to bonding pads on the base. Compliant cushions that generally conform to the shape and size of the chips are held loosely between the circuit sides of the chips, and the base. The heat sink enages the back sides of the circuit chips when it is attached to the base. This causes the chips to compress the compliant cushions, thereby holding the chips firmly in position, and forming a high thermal conductivity interface between the chips and the heat sink. To further enhance the heat transfer characteristics of the interface, a thin film of fluid is coated on the back sides of each chip to fill in the microvoids which result from asperity contact of the heat sink and chip mating surfaces. A sealing gasket is provided between the heat sink and the base to form a protective enclosure for the chips. Intermediate housings or heat spreader structures may alternatively be disposed between the chips and the heat sink.

Thermoelectric therapy device

Abstract: A therapeutic device is provided for heating or cooling the skin and underlying body tissue. The device includes a handle and a thermally conductive head secured to the handle. The head includes a thermally conductive contact plate which is thermally isolated from the head. One or more Peltier effect devices are provided for heating or cooling the contact plate depending upon the polarity of the current. The head and handle function as a heat sink for dissipating heat generated by the Peltier effect devices. A fan is also provided within the head for heat dissipation purposes. A bag or pouch filled with a thermally conductive fluid may be mounted to the head and positioned adjacent to the contact plate. The bag or pouch conforms to the surface of the body to which it is applied. A porous bag may be employed if moist heat is desired. The contact plate may be connected to a high voltage source if electrical stimulation is desired.

Thermal transfer bag

Abstract: A thermal transfer means comprising a flexible bag or pouch filled with a chemically inert, electrically nonconductive, nonflammable, essentially gas-free, thermally stable, thermally conductive, body of liquid comprising fluorochemical liquid. Said bag is fabricated from a flexible, durable plastic film that has low permeability to air and the fluorochemical liquid. The configuration of the bag is conformable to adapt to the geometry of the space, formed between the surface of a heat generating component or components and the surface of a heat sink, into which the bag is inserted, thereby contacting said surfaces and providing a thermal conduction path for heat generated by the heat generating component during operation from said component to the heat sink. The liquid has a boiling point such that it down not boil at the highest operating temperature of the device. Also provided is a method for making and filling the bag such that after sealing the bag is substantially gas free.

Crash survivable enclosure for flight recorder

Abstract: A crash survivable enclosure for flight data recorders used in aircraft and other vehicles operating over land and water includes a strong, light-weight metal shell for enclosing and protecting an information storage device having power, signal, and address lines connected thereto. The memory device is supported inside the shell in a wax filler of the type having a high melting temperature and a high heat of fusion to act as a heat sink for absorbing a large quantity of heat to minimize possible damage to the memory device because of excessive heat, flames and/or high temperature. A strong lightweight metal shell is provided to enclose and protect the inner shell and contents against substantial, external mechanical forces commonly occurring in a crash and flames, heat and fire resulting therefrom. A second filler of high efficiency, heat insulating material is provided for physically supporting the inner shell and contents and for providing protection against flame, fire and heat penetration as well as physical impact and shock penetration as would be encountered in a crash of an aircraft or other vehicle carrying the enclosure. The enclosure is especially designed to withstand prolonged immersion in salt water at substantial depths to provide protection against damage to the memory device so that pertinent recorded information is available upon retrieval of the enclosure after a crash.

X ray tube anode and tube having same

Abstract: An X-ray tube anode (32) has a thin metal film first layer (31a), e.g. W, for producing hard X-rays. A diamond (31b) second layer supports the first layer, conducts heat away from it, and transmits X-rays (34a, 34b). The layers usually have a maximum thickness of about the stopping distance of incident electrons. An X-ray tube has such an anode and a heat sink (38) in contact with the layers. The sink can have a beam dump (42) and a transmission mode X-ray window (36b). A normal mode X-ray window (36a) is in the tube envelope near the anode.

Enhancement of Critical Heat Flux From High Power Microelectronic Heat Sources in a Flow Channel

Abstract: Several surface augmentation techniques were examined in an investigation of enhancement of critical heat flux (CHF) from a simulated electronic chip to a fluorocarbon (FC-72) liquid in a vertical channel. A parametric comparison of boil­ing performances is presented for a smooth surface and for surfaces with low-profile microgrooves, low-profile microstuds, and high-profile pin fins. Critical heat fluxes as high as 361 W/cm

Molded integrated circuit package incorporating heat sink

Abstract: A molded integrated circuit package includes an integrated circuit chip, a heat sink device attached directly to the chip or lead frame and a molded package encapsulating the chip. The heat sink preferably comprises a thermally conductive material having a stem which communicates between the IC chip and the exterior of the molded package for direct conduction of heat from the IC chip to the exterior of the package.

Thermal heat sink encapsulated integrated circuit

Abstract: An encapsulated integrated circuit which includes an integrated circuit die having a plurality of electric leads extending from the die. A thermal heat sink is positioned adjacent the die. The heat sink includes a thermoplastic material having a plurality of thermoconductive particles molded therein. A non-electrically conductive plastic material is sealably connected to the heat sink and encloses the die and seals around the leads. The heat sink plastic material is filled approximately 50 percent with metal particles, preferably in the form of powder. The particles may be from a group consisting of copper, aluminum, iron, carbon, aluminum nitride, silicon carbide, and boron nitride. The heat sink and the non-conductive plastic material have coacting interlocking interfaces.

Heat transfer bag with thermal via

Abstract: A heat transfer bag especially useful for cooling electronic components is made of a flexible sheet of material and is filled with a fluorochemical heat transfer liquid. A metallic thermal via extends through a hole in the bag for direct contact with an external surface of a heat-generating component. A portion of the via extends into the bag and functions as a heat radiating fin to enhance the transfer of heat from the component to the liquid within the bag.

Analytical solution for the integral contact line evaporative heat sink

Abstract: Heat transfer by evaporation from a thin film is studied theoretically. The film thickness decreases with position and approaches an asymptotic value. The film is influenced by long-range iniermolecular forces, in particular van der Waals forces. According to the model, as well as previous models, these forces may partially suppress evaporation, locally, but may draw fluid into the thin film from a bulk pool, generally. The insulation effect of the fluid is included, whereas, capillary and thermocapillary effects are not considered. Analytical expressions are presented for the film slope, curvature, and flow in terms of the film thickness. The film is semi-infinite and steady, therefore, the flow at some position is equal to evaporation from the portion of the film downstream of that position and is proportional to the integral heat sink. Curvature may become quite large for small film thicknesses. An expression for the film thickness as a function of position is presented for the special case of a relatively strong insulation effect. Also presented is an engineering model relating the integral heat sink to a reduction in the Laplace pressure driving force for porous media flow, through a dynamic contact angle.

Semiconductor device having an insertable heat sink and method for mounting the same

Abstract: A semiconductor device is disclosed having an electronic component mounted to a mounting surface opposite a heat transfer surface of a die support member. The electronic component includes a plurality of bonding pads each electrically coupled to a plurality of package leads by a number of inner leads. A package body encloses the electronic component, the inner leads, the proximal ends of the package leads and the mounting surface of the die support member. The package body includes an opening exposing a portion of the heat transfer surface of the die support member. An insertable thermally conductive heat sink extends into the opening in the package body making thermal contact with the heat transfer surface of the die support member. A thermally conductive electrically insulating adhesive joins the heat sink to the package body securing the heat sink to the package body. In the assembly process, the package body is formed prior to attachment of the heat sink. During the process of soldering the package leads of the semiconductor device to a mounting substrate, gasses within the package body can escape through the opening before excessive pressure buildup occurs within the package body.

A review of thermal enhancement techniques for electronic systems

Abstract: The demand for electronic components which will satisfy performance standards over a wide range of environmental conditions requires the use of thermal enhancement techniques. Recent thermal enhancement techniques for maximizing the thermal contact conductance, including greases, metallic foils and screens, composite materials and cements, and surface treatments are reviewed. The relative merits of the various enhancement techniques are summarized, and comparisons are made for selected thermal enhancement materials. For most electronic component uses, the use of greases poses a significant problem because of the potential for vaporization and/or migration to other surfaces in the component. The use of metallic foils and screens can provide thermal enhancement at an interface, depending upon the material properties as well as the contact temperature and applied load on the interface. There are a number of synthetic materials which can be used for thermal enhancement, and new materials are continuously being developed. Surface preparation or selected surface finishes can be used to enhance the heat transfer at an interface. Thin layers of vapor-deposited soft metals have been shown to improve the overall heat transfer at an interface significantly. >