Application of WLP with barrier trench structure in precision screen printing technology by glass frit

This paper reports on glass frit wafer bonding, which is a universally usable technology for Micro-Electronics Mechanical System (MEMS) wafer level encapsulation and packaging. The package process demonstrated from DEK-APi screen printing of glass frit, firing to wafer bonding by glass frit. However, the dimensions of glass frit after bonding are nonuniform and some frit widens to reach MEMS device, resulting in package failure. A new improved technology (Barrier trench technology, BTT) is developed. And in process of bonding, glass frit expanding in bonding force is resisted by the BTT. The uniformity of bonded glass frit dimension can be achieved. It allows hermetic sealing and a high process yield. And shear test, water test for the gross leak and fine leak test results fulfilled the corresponding MIL-STD.