A graphite sheet having a ratio of thermal diffusivity in horizontal and vertical directions of 300 or more is disclosed. Also, a graphite sheet having a ratio of thermal diffusivity in a vertical direction of 2.0 mm.sup.2/s or less is disclosed. The graphite sheet has excellent thermal conductivity in horizontal and vertical directions and excellent flexibility at the same time and can be produced at low manufacturing cost, thereby holding an economic advantage.

A semiconductor device has an electrical component and a first TIM with a first compliant property is disposed over a surface of the electrical component. A second TIM having a second compliant property greater than the first compliant property is disposed over the surface of the electrical component within the first TIM. A third TIM can be disposed over the surface of the electrical component along the first TIM. A heat sink is disposed over the first TIM and second TIM. The second TIM has a shape of a star pattern, grid of dots, parallel lines, serpentine, or concentric geometric shapes. The first TIM provides adhesion for joint reliability and the second TIM provides stress relief. Alternatively, a heat spreader is disposed over the first TIM and second TIM and a heat sink is disposed over a third TIM and fourth TIM on the heat spreader.

In a general aspect, an apparatus can include an inner package including a first silicon carbide die having a die gate conductor coupled to a common gate conductor, and a second silicon carbide die having a die gate conductor coupled to the common gate conductor. The apparatus can include an outer package including a substrate coupled to the common gate conductor, and a clip coupled to the inner package and coupled to the substrate.

Enhanced thermal energy transfer systems for semiconductor packages are provided. A thermally conductive member is disposed in the interstitial space between an upper surface of a semiconductor package and a lower surface of a thermal member. The thermally conductive member is disposed above a first portion of the upper surface of the semiconductor package having a relatively higher thermal energy output when the semiconductor package is operating. A thermal interface material is disposed in the interstitial space and a force applied to the thermal member. The thermally conductive member forms a relatively higher pressure region above the first portion of the semiconductor package and a relatively lower pressure region in other portions of the semiconductor package remote from the thermally conductive member. The increased pressure region proximate the thermally conductive member beneficially enhances the flow of thermal energy from the first portion of the semiconductor package to the thermal member.

Provided is a thermal conduction sheet, including graphite particles (A) of at least one kind selected from the group consisting of flake-shaped particles, ellipsoidal particles, and rod-shaped particles, in which: when the graphite particles (A) are flake-shaped particles, a planar direction of the graphite particles (A) is oriented in a thickness direction of the thermal conduction sheet, when the graphite particles (A) are ellipsoidal particles, a major axis direction of the graphite particles (A) is oriented in the thickness direction of the thermal conduction sheet, when the graphite particles (A) are rod-like particles, a longitudinal direction of the graphite particles (A) is oriented in the thickness direction of the thermal conduction sheet, the thermal conduction sheet has an elastic modulus of 1.4 MPa or less under a compression stress of 0.1 MPa at 150° C., and the thermal conduction sheet has a tack strength of 5.0 N.Math.mm or higher at 25° C.

A package structure including a circuit board and a heat generating element is provided. The circuit board includes a plurality of circuit layers and a composite material layer. A thermal conductivity of the composite material layer is between 450 W/mK and 700 W/mK. The heat generating element is disposed on the circuit board and electrically connected to the circuit layers. Heat generated by the heat generating element is transmitted to an external environment through the composite material layer.

A package structure including a circuit board and a heat generating element is provided. The circuit board includes a plurality of circuit layers and a composite material layer. A thermal conductivity of the composite material layer is between 450 W/mK and 700 W/mK. The heat generating element is disposed on the circuit board and electrically connected to the circuit layers. Heat generated by the heat generating element is transmitted to an external environment through the composite material layer.

Heat is transferred to a cold plate from one or more subassemblies in an array of subassemblies in an electronic package. The cold plate has a thermally conductive cold plate substrate, a pressure header, a pressure passage, and one or more pressure connections. Each of the pressure connections connects through a housing opening to housing volume defined by a flexible housing in an encapsulated liquid thermal interface (LTI). The flexible housing is in physical and thermal contact with one of the subassemblies through a housing bottom and a top surface of one or more components in the subassembly. A thermally conductive fluid fills the housing volume, housing opening, pressure connections, pressure passage, and pressure header which are all in fluid communication along with one or more other connections, housing openings, and LTIs on other subassemblies. The system transfers heat from the subassemblies to the cold plate while maintaining a constant pressure/stress on each of the subassemblies. The system pressure on each of the subassemblies is equal. The system pressure can be controlled to a preloaded pressure to insure good electrical contact between components. Shear on the subassemblies is minimized by the LTIs.

Heat is transferred to a cold plate from one or more subassemblies in an array of subassemblies in an electronic package. The cold plate has a thermally conductive cold plate substrate, a pressure header, a pressure passage, and one or more pressure connections. Each of the pressure connections connects through a housing opening to housing volume defined by a flexible housing in an encapsulated liquid thermal interface (LTI). The flexible housing is in physical and thermal contact with one of the subassemblies through a housing bottom and a top surface of one or more components in the subassembly. A thermally conductive fluid fills the housing volume, housing opening, pressure connections, pressure passage, and pressure header which are all in fluid communication along with one or more other connections, housing openings, and LTIs on other subassemblies. The system transfers heat from the subassemblies to the cold plate while maintaining a constant pressure/stress on each of the subassemblies. The system pressure on each of the subassemblies is equal. The system pressure can be controlled to a preloaded pressure to insure good electrical contact between components. Shear on the subassemblies is minimized by the LTIs.

An electronic assembly includes a flexible printed circuit board (PCB) circumferentially disposed around a motor and a thermal management assembly (TMA) thermally connected to the flexible PCB. One or more switching semiconductor devices are disposed on a first surface of the flexible PCB. The TMA includes a cooling jacket, at least one jacket manifold formed through the cooling jacket and a thermal compensation base layer thermally coupled to the cooling jacket. The cooling jacket is mounted around a circumference of the motor and has a mounting surface concentric with the circumference of the motor. The mounting surface is coupled to the first surface of the flexible PCB. The at least one jacket manifold has a fluid inlet and a fluid outlet defining a fluid flow area therebetween. The thermal compensation base layer is thermally coupled to the cooling jacket and the one or more switching semiconductor devices.