Development of wafer level glass frit bonding by using barrier trench technology and precision screen printing

A new technology in wafer-level packaging by glass frit bonding is developed for wafer level encapsulation of MEMS devices. To improve the uniformity of the dimension of glass frit, a new barrier trench technology (BTT) is developed during bonding process. Glass frit expanding caused by bonding force is well resisted by the BTT. An improved uniformity of bonded glass frit dimension is achieved. Meanwhile, the residual stress of glass frit bonded MEMS wafer with BTT is analyzed by using Finite Element Analysis method. Shear test and water test are also carried out, the gross leak and fine leak test demonstrate that the results fulfill the corresponding MIL-STD. A hermetic sealing and a high process yield are realized.

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► The small glass frit with 100 μm in width by precise screen printing was achieved.
► An improved uniformity of bonded glass frit dimension is achieved by BTT.
► The residual stress of glass frit with BTT and without BTT is analyzed by using FEA.
► A hermetic sealing and a high process yield are realized by WLP glass frit bonding.