| In today’s era of rapid development of the electronics industry, with the development of thick film hybrid integrated circuit towards high performance, high reliability, miniaturization, high uniformity and low cost direction, put forward higher requirements of thick film hybrid circuit assembly technology and process. In the thick film hybrid integrated circuit, power module is the core device, determines the response of thick film component properties and thermal power. In the assembly of thick film power components, now the main problem is: the welding device more empty, so the heat generated when the work can not be effectively divergent, eventually make the device junction temperature is high, reducing its service life, and even individual parts due to voltage breakdown due to high temperature.There are many factors affecting the voids, through the literature, combined with the development status at home and abroad, respectively from the shell, thick film substrate size; solder composition, state(pad, solder) selection; process curve(vacuum, reducing atmosphere, temperature setting) to reduce all aspects of small hole rate, then, by the appearance of X ray, metallographic analysis, shear stress test analysis of thick film power devices, the reliability of the hole rate, find out the real reason for the formation of empty solder is in the process of sintering residual gas and oxides can not be discharged. The results show that: in the process of reflow temperature curve, welding thickness, stress analysis, find the suitable parameters to improve the welding hole problem. The temperature curve is one of the most significant factors affecting the welding hole size, vacuum welding, pressure curve, through the process of acid control, vector roughness, atmosphere analysis, found the suitable parameters to improve the welding hole, draw process curve, atmosphere protection is the most significant factors affecting the welding hole size. |
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