均匀钎料熔滴喷射装置设计

针对现有焊球生产设备结构复杂、成本高等缺点，设计了实验室用均匀钎料熔滴喷射装置。该装置分为压力控制器、液滴生成器、气体保护装置以及冷却凝固装置四个部分。其中液滴生成器采用喷嘴局部缩径，使熔滴在表面张力差及重力的作用下实现分离，有效地简化了装置的结构，降低了成本。利用所设计的装置对Sn3.0Ag0.5Cu焊球的制备工艺进行优化，并对优化工艺参数下制备的焊球从表面形貌与球形度、焊球尺寸分布以及钎料微观组织等方面进行质量评定。结果表明：喷射压力、喷嘴到冷却介质表面的距离以及喷嘴内径是影响焊球成形的主要因素。优化工艺参数下制备的焊球尺寸均匀、表面光亮、球形度好、内部组织细密无缺陷。所设计的装置能够满足实验室研究钎料喷射过程以及焊球制备的需要。

Design of Uniform Solder Droplets Jet System

As the existing commercial equipment for solder ball fabrication are commonly complicated and expensive, a simple solder jet system which can produce uniform solder droplets is presented for the experimental researches. There are four main components in this novel system, i.e. the pressure controller, the droplet generator, the shielding gas chamber, and the cooling and solidifying system. To simplify the droplet generator structure, the jetting tube with a shrinkage tip is used to force the solder droplet to separate from the nozzle under the effects of gravity and surface tension. The process optimization for Sn3.0Ag0.5Cu solder balls fabrication is performed. The solder balls produced by the presented equipment are evaluated in the following aspects: the solder topography and sphericity, the solder size deviation, and the microstructure of the solder. It is found that the jetting pressure, the distance from the nozzle to the surface of cooling medium, and the inner diameter of the jetting tube are the major factors that influence the formation of solder balls. The solder balls fabricated under the optimized process parameters are uniform, spherical, non-oxidation, and have fine and flawless microstructures. The presented equipment can meet the requirements for the experimental researches of the solder jetting process and the solder balls fabrication.