氮化硅陶瓷覆铜基板制备及可靠性评估

Fabrication and Reliability Evaluation of Silicon Nitride-Copper Ceramic Substrates

氮化硅陶瓷覆铜基板优异的高可靠性使其成为高铁、电动汽车等领域功率模块最有前途的基板材料之一,目前只有日本厂商具备量产能力,国内进口困难,阻碍了相关产业的发展。采用气压烧结实现了高性能氮化硅陶瓷基板的制备,并通过活性金属钎焊工艺获得了氮化硅陶瓷覆铜基板。氮化硅陶瓷的弯曲强度800 MPa,断裂韧性8.0 MPa·m1/2,热导率90 W/(m·K),交流击穿强度40 kV/mm和体积电阻率3.7×1014Ω·cm;氮化硅陶瓷覆铜基板的剥离强度达到130 N/cm。在-45~150℃高低温循环冲击下,氮化硅陶瓷覆铜基板的冲击次数分别达到氮化铝和氧化铝覆铜基板的10倍和100倍;在铜厚0.32 mm/0.25 mm冲击次数达5000次和铜厚0.5 mm/0.5 mm冲击次数达1000次的情况下,样品均完好无损;在铜厚0.8 mm/0.8 mm冲击次数达500次时,样品仍未产生微裂纹等缺陷,这与铜厚0.32 mm/0.25 mm时氮化铝覆铜基板的循环次数相当;氮化硅陶瓷覆铜基板的可靠性明显优于现有产品。

The high reliability of silicon nitride-copper ceramic substrates makes it one of the most promising materials for the power electronics in the field of high-speed train,electric cars,and etc.The import from Japan is expensive and time consuming which is an obstacle for the development of related industries.High performance silicon nitride ceramic was fabricated by gas pressure sintering.And the silicon nitride-copper ceramic substrate was obtained by active metal brazing method.The bending strength of silicon nitride ceramics is 800 MPa.The fracture toughness is 8.0 MPa·m1/2.The thermal conductivity is 90 W/(m·K).The breakdown strength under alternate current is 40 kV/mm.The volume resistivity is 3.7×1014Ω·cm.The peeling strength of the silicon nitride-copper ceramic substrates by active metal brazing is 130 N/cm.The thermal shock test was carried out under-45-150℃.As a result,the cycles of silicon nitride-AMB-copper ceramic substrates are 10 times and 100 times than the aluminum nitride-AMB-copper and alumina-DBC-copper ceramic substrates,respectively.As the thickness of copper is 0.32 mm/0.25 mm,the cycles reach 5000 times;and the thickness of copper is 0.5 mm/0.5 mm,the cycles reach 1000 times;both the silicon nitride-AMB-copper ceramic substrates are in good condition without microcracks.As the thickness of copper is 0.8 mm/0.8 mm,the cycles reach 500 times without microcracks,which is similar to the cycles of the aluminum nitride-AMB-copper ceramic substrates with the copper thickness of 0.32 mm/0.25 mm.The reliability of silicon nitride copper-ceramic substrates is obviously better than aluminum nitride products.