底部填充工艺的瞬时温度环境管理

微电子组装的大部份工艺开发都要求将元件做到更小,以便在尺寸日益缩小的便携式设备上实现更多功能。阐述了大元件的底部填充,即一侧的尺寸超过15mm,底部填充的胶量介于30～50mg。大尺寸晶元的制造工艺要求比现有生产线更大的产能,这就给底部填充点胶带来更大的挑战。大元件的产能超过3000个/h时,需要点胶机点出非常多的胶水。如此多的胶水在出胶前通过点胶阀,这将会带来加热的问题-某些工艺要求出胶前胶水必须要加热。这会对胶点尺寸有影响,因为随着温度的变化,底部填充的胶水黏度也会随之变化,从而轻微影响点出的胶量。从而将影响晶元相邻的“非沾染区”。稳定的温度是点胶稳定性的保证,并且能帮助胶水流进晶元下方同时也有助胶水分离从而更容易喷射出来。从研究中可以观察到：系统温度环境（点胶机内部）对点胶的胶水质量有影响。

Managing Transient Thermal Environments During the Underfill Process

In the world of microelectronic assembly most process developments are aimed at making smaller components to fit more functions into ever smaller portable devices. This study was designed to look at large device underfill, where the silicon die is over 15 mm on a side, and the amount of underfill required is on the order of 30 to 50 nag. The manufacturing process for these large die are pushing throughput requirements to much higher levels than seen on production lines today, bringing new chal-lenges to dispensingunderfill.When such large devices are produced at rates over 3 000 uph the have to move a lot of material. The sheer volume of material passing through a jet may present problems in heating fluids to the desired process temperatures before dispensing. This impacts the accuracy of shot size because underfill fluids change viscosity with changes in temperature, and for a given cycle, a jet's shot volume can changeslightly. This in turn impacts material keep-out zones next to the die. Constant temperature of the underfill fluids results in greater repeatability of shot size, aids flow under the die, and improves fluid break off. During this study, it was also observed that the system thermal environment (inside the dispensing machine) had an impact on the shot weight dispensed.