Optimization of gas-flow condition for a real scale semiconductor packaging process using the Photodesmear® method

Abstract

In recent years, the requirements of semiconductor packaging technology have become smaller and finer, while the miniaturization of the semiconductor and the shrinkage of the package size are demanded. The fine process as that used in the semiconductor manufacturing process is attempted in for the production of the semiconductor packaging process, but it is so difficult due to large size work, different materials, controlling process conditions and so on. We have been studying the practical application of the Photodesmear® process using vacuum ultraviolet (VUV) light. (Habu et al. 46th Int. Symp. in Microelectronics, 2013, Horibe et al. The Japan Institute of Electronics Packaging 2014, 2014, Habu et al. IMAPS 2015, 48th Int. Symp. in Microelectronics, 2015, Namai et al. IEEE2016 Electric Components and Technology Conf., 2016, Endo et al. IMAPS 2016 49th Int. Symp. in Microelectronics, 2016, Takezoe et al. Japan Patent WO2015/108184, 2015, Hirose et al. Japan Patent 5987815, 2016, Takezoe et al. Japan Patent 6135764, 2017, Endo et al. Int. Microsystem Packaging Assembly and Circuit Technology Conf., 2017, Endo et al. Micro Electronics Symp. 2019, 2019). Photodesmear® processes that utilize high power VUV light and high oxygen concentration atmospheres have the potential to replace desmear processing in future semiconductor packaging processes. In this study, we particularly focused on the oxygen flow velocity in optimizing the Photodesmear® process. We evaluated the uniformity of the desmear process with a large practical size device and found the problems associated with the increase in size. By measuring and calculating the ozone concentration and oxygen concentration in the atmosphere, the factors of the flow velocity dependence of the reaction gas were considered for the improvement of the uniformity in the Photodesmear® process.