芯片强度改进——减薄前划片+等离子包蚀刻(英文)

Die Strength Improvement——Dbg+ Plasma Etching

对于目前的多层芯片封装和IC卡, 不仅在组装工艺的提高良品率中要求芯片强度高, 而且在封装之后还要求有更好的使用期限。根据更薄晶圆的要求, 引入了消除晶圆减薄引起损伤的各种应力解除方法, 但在应力解除之后的划片中又引起了机械损伤, 通过这些方法不可能使芯片强度达到最大。因此, 我们开发了一种结合减薄前划片(DBG)的等离子蚀刻的应力解除方法。减薄前已完成划片工序的晶圆可在其底面和划切面同时用氟基蚀刻, 从而消除机械损伤。我们已能够通过比较经历过常规应力解除芯片来确认被改进芯片强度的平均、最小、最大值。可以预期这项技术将被用于提高今后将进一步扩展的IC卡(即信用卡, 身份证)的寿命要求。

For the current multiplayer die packages and IC cards, high die strength is required not only for the enhancement of yield in the assembly process but also for better durability after the packaging. In accordance with the requirement for thinner wafers, various methods of stress relief which eliminates damage caused by the grinder have been introduced, but as the dicing after the stress relief causes mechanical damage again, it is not possible to maximize the die strength by these methods. Thus, we have developed a method which eliminates the grinding damage by combining stress relief using plasma etching with DBG （Dicing Before Grinding）. The DBG wafer which has already been diced at the time of being thinned can be etched on the ground surface and the cut surface at the same time using the F（fluorine） radical, thereby eliminating the mechanical damage. We have been able to confirm that average, minimum and maximum values for die strength could be improved compared with die that underwent the conventional stress relief. It is expected that this technology will be applied to enhance durability of IC cards （e.g., electronic money, ID cards） whose demand will be expanded in the future.