OKI Develops PCB Technology with Stepped Copper Coin Insertion to Achieve 55 Times Better Heat Dissipation in Outer Space

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The OKI Group printed circuit board (PCB) business company OKI Circuit Technology has successfully developed multi-layer PCB technology with stepped copper coin insertion to achieve 55 times better heat dissipation compared to conventional PCB. The stepped copper coin is offered in two types, circular and rectangular, to suit the shape of the electronic component mounted on the PCB. OTC is working to develop mass-production technologies with the aim of introducing PCBs incorporating this new technology into markets for compact devices or devices used in outer space or other environments where air cooling technology cannot be used.

As semiconductors have become smaller and more sophisticated, countermeasures against the heat generated when processing large volumes of data at high speed have become an issue. In cases where device miniaturization prevents the installation of cooling fans or heat sinks or in vacuum environments such as outer space where air cooling technology cannot be used, PCBs are required to have heat dissipation structures with high heat conduction efficiency capable of transferring and dissipating the heat generated by PCB-mounted electronic components to the outside such as to a casing.

In 2015, OTC developed proprietary design and mass production technologies for multi-layer PCBs based on copper coin insertion. This innovation embeds cylindrical copper coins with high thermal conductivity (Note 2) into PCB through-holes (Note 3) and bonds them to heat-generating electronic components to dissipate heat to the underside of the substrate. The use of copper coins that transfer heat to the underside of the PCB achieves high heat dissipation efficiency in cases where it is not possible to mount heat-dissipating devices directly to electronic components due to dimensional constraints of the device or where heat-dissipating devices cannot be mounted to certain functional surfaces (e.g., image sensors or light-emitting components). This time, OTC has made further progress with this technology and succeeded in developing the stepped copper coin that achieves approximately twice the heat dissipation efficiency (Note 4).

The newly developed stepped copper coin features a larger heat-dissipating area relative to the bonding surface with the heat-generating electronic component to improve heat conduction efficiency. Additionally, aiming for an optimal heat dissipation structure to suit the shape of each electronic component, a rectangular type featuring a rectangular component installation surface and rectangular heat-dissipating surface has been developed, in addition to the conventional circular type, to increase the contact area and heat-dissipating area for rectangular electronic components to improve heat dissipation efficiency. Both types can be customized to obtain an optimal heat dissipation structure for the given shapes of the mounted component and the PCB itself and the substrate thickness. According to OTC President Masaya Suzuki, the stepped copper coin enables heat dissipation structures with high heat conduction efficiency to transfer and dissipate the heat generated by PCB-mounted electronic components to the outside such as to a casing in compact devices or in environments such as outer space where air cooling technology cannot be used.

Having positioned the aerospace markets as a key focal point for its EMS business, OKI provides “space-quality” manufacturing services (EMS) ranging from the design and production of PCBs certified for all seven schedules of the JAXA (Japan Aerospace Exploration Agency) standards, cables, and other core components; simulations at the design stage; component screening and process diagnostics; to device reliability evaluations and failure analysis; PCB mounting (soldering and resin sealing); and unit assembly. OKI plans to continue advancing technology development and expanding sales for the global aerospace markets.