基于填充式缓冲结构的低应力TSV设计OA

With the continuous advancement of three-dimensional integration and MEMS devices toward higher integration density and reliability,interfacial thermal stress concentration induced by the mismatch of coefficients of thermal expansion under thermal loading is increasingly observed in conventional through-silicon via(TSV)structures and is regarded as a critical factor affecting device reliability.To address this issue,a filled buffer-structure TSV design is proposed without altering the main TSV via structure or the existing basic fabrication process.An annular buffer trench filled with a low-Young's-modulus material is introduced around the via to alleviate interfacial stress concentration.Based on this structural design,the effects of TSV geometric parameters and buffer-structure parameters on thermal stress are analyzed using finite element simulations.The results indicate that when the via is cylindrical with a diameter of 50 μm,the buffer width,spacing and depth are each set to 5 μm,and benzocyclobutene(BCB)is selected as the filling material,the maximum thermal stress of the TSV is reduced to 540.35 MPa,corresponding to a reduction of approximately 28.6%compared with a TSV without a buffer structure.This design provides a feasible approach for achieving low-stress and high-reliability TSV interconnections within the existing process framework.