We developed insulated circuit board used in IGBT (Insulated Gate Bipolar Transister) , which is used as a high power frequency conversion device such as a hybrid car, a fuel cell car, an electric vehicle, a Shinkansen, CS-DBC). In recent years, when SiC replaced Si for semiconductor, SiN for insulating ceramics, and 1mm thick copper for circuit are used. We offer ceramic/copper joints by diffusion bonding.



Features of our products

  • Improvement of thermal conductivity by absence of bonding layer
  • Strong adhesion
  • New construction method by proprietary development (S-DBC)
  • correspond to SiN · AlN · Al2O3

S-DBC method (Developed by FJ Composite)
S-DBC:Sputtering Diffusion Bonding Copper


Conventional method


S-DBC method


※In S-DBC method, better bonding of SiN and Cu is observed compared with conventional method.

Joining strength evaluation · Heat cycle test result

Joining strength evaluation of thermal diffusion bonding
(user evaluation result)

AMB (other company’s product)98 N/4mm²
S-DBC (FJ Composite)106 N/4mm² (destruction of ceramic base material)


Before testing (Cu / SiN / Cu specimen)

テスト後(接合強度 > セラミックス強度)

After testing (bond strength> ceramic strength)

Heat cycle test

①High temperature operation Reliability test (-45 to 150 ° C / cycle, dwell time 20 min, @ each Temp)
-45 ~ 150 ° / 2000 times Test passed (User evaluation)

②Observation result of DBC circuit board bonding state
-40 to 250 ° / 3000 times Test passed (AIST evaluation result)


External evaluation

Nominated for AIST’s technical support outcome case

Nominated for AIST technical support best practice In 2012, we developed a ceramic insulated circuit board (DBC) used for power semiconductors by a new bonding technology (diffusion bonding) and it was nominated one of 4 best practices of technical support for AIST’s small and medium-sized enterprises.


Newspaper posting

Establishment of mass production technology for ceramics insulating board by diffusion bonding, which is with excellent in heat dissipation was taken up in Nikkan Kogyo Shimbun (June 3, 2014 issue). Nikkan Kogyo Shimbun newspaper electronic version
Nikkan Kogyo Shimbun web version

日刊工業新聞 電子版