Showa Denko Materials Co., Ltd. announced that MCL-LW-900G/910G, a low transmission loss printed wiring board material developed by the company, has been adopted for the printed wiring boards mounted on the central processing units (CPU) of the supercomputer Fugaku, currently under joint development by the RIKEN and Fujitsu Limited. The worlds No.1 supercomputer known as Fugaku aims to deliver up to 100 times the application execution performance of its predecessor, K computer that began operating in 2012, while minimizing its power consumption (30-40 MW) roughly three times that of K computer (12.7 MW). Fugaku is expected to play a major role in various fields, including COVID-19 research, artificial intelligence (AI) applications, and big data analysis. To combine superlative computing speed and power-saving performance of Fugaku, higher speed communication, larger data volumes, and higher frequency electric signals are required for printed wiring boards. However, to provide these capabilities, it is essential to reduce transmission signal attenuation (transmission loss) and signal delay within the boards. Halogen-free material is also an important requirement to reduce environmental impact. Showa Denko Materials developed MCL-LW-900G/910G as a halogen-free printed wiring board material capable of reducing transmission loss and signal delay by optimizing resin composition ratio and applying low dielectric glass cloth. This material is excellent for drilling holes and is applicable to laser drilling fine holes. It also effectively reduces the price of high layer count printed wiring boards as the material can be laminated collectively in a hybrid configuration with halogen-free FR4 (a general-purpose glass cloth base material) with different glass transition temperatures (Tg).
As a material for the supercomputer Fugaku, MCL-LW-900G/910G has been well-received for its properties such as low dielectric constant (Dk) and dielectric loss tangent (Df) related to transmission loss and signal delay, as well as insulation reliability (CAF resistance) and desmear treatment (desmear solubility) which improve printed wiring board production yields and ensure stable production. Showa Denko Materials will work to further optimize the resin composition ratios and use lower dielectric glass cloth to launch mass production of printed wiring board materials focused on low transmission loss with a view to applying these materials to fifth-generation (5G) and sixth-generation (6G) mobile communication systems providing even higher speed, higher capacity, lower latency, and multiple connections.