Technical Notes

Noise suppression thermal conductive sheets Carbon fiber type

What is a thermal conductive sheet?

A thermal conductive sheet is a type of heat management material called TIM (Thermal Interface Material) that transfers heat from a heat source to a heat dissipating component. A thermal conductive sheet is inserted between an IC chip (heat source) and a heat sink (heat dissipating component) to enhance the heat dissipating effect and protect electronic devices.
Downsizing and enhanced performance of electronic devices has also led to increased heat generated from components such as IC chips, and, as a countermeasure, we began producing thermal conductive sheets in 2004. In addition to silicone and acrylic types that feature high thermal conductivity and flexibility, we have developed a carbon-fiber type for applications with higher heat generation which is now widely used in, for example, electronic devices, servers and 5G communication base stations, that require high-speed and large-capacity information processing.

Performance required for thermal conductive sheets

In addition to thermal conductive performance, an equally important characteristic upon designing a thermal conductive sheet is flexibility. When a thermal conductive sheet is adhered to an adherend, it serves to absorb the dimensional tolerance of the adherend while reducing stress on the circuit board. To do so, the sheet need to be very flexible.

Types and features of our thermal conductive sheets

The silicone type is a thermal conductive sheet that features high heat conduction, flexibility and insulation performance. This type is made of high heat resistant silicone filled with ceramic-type heat conductive filler such as alumina at high density.

The acrylic type does not produce low molecular weight siloxane that causes contact failure of components such as circuit boards, therefore, is suitable to be used in a sealed environment.

With carbon fiber as the thermal conductive filler, the carbon fiber type realizes high thermal conductivity and excellent flexibility by applying our proprietary orientation technology. This type is used for devices with high heat generation density such as LSI.

Need for noise suppression function

With recent increases in the operating frequency of components such as ICs, together with integration and downsizing of electronic devices, measures to cope not only with heat generation but also with high-frequency noise, represent a major issue. This has led us to develop the “EX10000K3 series,” a carbon-fiber type thermal conductive sheet featuring extremely high thermal conductivity　and noise-suppressing effect.

Outline of EMI countermeasures

The noise absorption effect

The noise absorption effect is a phenomenon that attenuates electromagnetic waves by magnetic, dielectric and conductor loss. Noise passing through the sheet can be reduced by using carbon fibers and magnetic materials to increase each of these losses.
In addition, shield performance can also be realized with a sealed structure, made by placing this sheet between the shield can (surrounding the IC) and the heat dissipating parts (heat sink).
This product was developed utilizing knowledge and technologies amassed through trial and error, such as optimization of material shape, combination ratio of particle diameters and mixing conditions.

Research & Development

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