Pressureless sintering multi-scale Ag paste by a commercial vacuum reflowing furnace for massive production of power modules
Pressureless sintering multi-scale Ag paste by a commercial vacuum reflowing furnace for massive production of power modules
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DOI：
10.1007/s10854-019-01297-x
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发表时间：
2019-05-01
影响因子：
2.8
通讯作者：
Lu, Guo-Quan
中科院分区：
文献类型：
--
作者：
Yan, Haidong;Mei, Yun-Hui;Lu, Guo-Quan
空气对Ag烧结至关重要。在空气中使用银浆键合功率器件时，非金属化直接键合铜（DBC）基板的铜表面会被严重氧化。本文提出了一种在甲酸蒸汽中用工业真空回流炉无压烧结多尺度银浆的方法。研究发现，甲酸蒸汽的活化温度对多尺度银浆的烧结行为有明显的影响。采用真空回流炉在180 ℃下快速通入甲酸蒸汽，可以使多尺度银浆获得更致密的银烧结体。在甲酸蒸汽中烧结的Ag纳米粒子颈大于0.4 μ m，孔隙率低于11.3%，具有比Ag纳米粒子（NPs）浆料更好的烧结性能。通过在甲酸蒸气中烧结多尺度Ag浆料的1200 V/50 A半桥IGBT模块的热阻为0.41摄氏度/W，这比使用Pb92.5Sn5Ag2.5的商业IGBT模块的热阻低约12%。本工作克服了在工业真空回流炉中用甲酸蒸汽对非金属化DBC衬底进行Ag烧结和Cu氧化的矛盾。该方法对于传统制造商非常有用，他们不必投资任何新的烧结设备。
Air is critical to Ag sintering. The Cu surface of the non-metallized direct-bonding-copper (DBC) substrate can be oxidized seriously for bonding power devices using Ag paste in air. In this paper, we presented a pressureless sintering approach for a multi-scale Ag paste in the formic acid vapor by a commercial vacuum reflowing furnace. The study found that the activation temperature of the formic acid vapor had an obvious effect on the sintering behavior of the multi-scale Ag paste. The multi-scale Ag paste could obtain much denser sintered Ag when the formic acid vapor was rapidly injected at 180 degrees C by the vacuum reflowing furnace. The sintered Ag necks larger than 0.4m and the porosity lower than 11.3% were achieved in formic acid vapor, which had better sintering behavior than Ag nanoparticles (NPs) paste. The thermal resistance of 1200V/50A half-bridge IGBT modules by sintering the multi-scale Ag paste in formic acid vapor was 0.41 degrees C/W, which was similar to 12% lower than those of the commercial IGBT modules using Pb92.5Sn5Ag2.5. This work could overcome the contradiction between the Ag sintering and the Cu oxidation of the non-metallized DBC substrate by the formic acid vapor in a commercial vacuum reflowing furnace. The method is extremely useful for the traditional manufacturer, who do not have to invest any new facilities for the sintering.