TSV constraints related to temperature excursion, pressure during molding, materials used and handling loads

Abstract

The current paper focuses on several mechanical aspects of a waferlevel packaging approach using a direct face-to-face Chip-to-Wafer (C2W) bonding of a MEMS device on an ASIC substrate wafer. Requirements of minimized inherent stress from packaging and good decoupling from forces applied in manufacturing and application are discussed with particular attention to the presence of through-silicon vias (TSV) in the substrate wafer. The paper deals with FEM analysis of temperature excursion, pressure during molding, materials used and handling load influence on mechanical stress within the TSV system and on wafer level, which can be large enough to disintegrate the system

Stress analysis of shielding electrode in chip with pressure sensor embedded in accelerometer

“…On the other hand, the finite element model of the chip with a copper shielding electrode was adopted to show the improvement after using nonlinear analysis with the stress–strain curve of copper (Falat et al , 2009; Iannuzzelli, 1991) as well. Furthermore, the maximum stress in each direction of the shielding electrode for the original and proposed designs after residual stress analysis is summarized in Table III.…”

“…The results show that as the thickness of the shielding electrode increased, the maximum von Mises stress increased at the corner and interface between the shielding electrode and the glass substrate. Also, the maximum von Mises stress of the copper shielding electrode was below its tensile strength (220 MPa) (Falat et al , 2009). Moreover, the maximum stresses in the X direction (in-plane of the chip), Y direction (out-of-plane of the chip) and XZ direction (in-plane shear of the chip) were also analyzed.…”

“…Furthermore, the stress–strain curve at various temperatures for the copper shielding electrode was used in the nonlinear analysis (Falat et al , 2009; Iannuzzelli, 1991). The difference between the linear and nonlinear analyses is discussed in this work.…”

“…Linear and nonlinear analyses were considered for discussion of the structural design of the shielding electrode; therein, stress–strain curves at various temperatures were also used for the copper shielding electrode (Falat et al , 2009; Iannuzzelli, 1991) in the nonlinear analysis. The thermal loading and boundary conditions in the finite element analysis were the same.…”