Reliable material parameters, correct boundary condition settings, and a reasonably simplified numerical model are key to obtain reliable and reasonable analysis results. A new finite element analysis model for the HgCdTe infrared focal plane array detector is presented, which includes the core column. The thermal stress and strain of the new model and current model are analyzed, and their distribution laws are obtained. The results are compared, and the reasons are analyzed, which can provide some references for the simulation of infrared detector package structure.

Electron beam welding of TC4 titanium alloy and 4J29 Kovar alloy was performed by using different thicknesses of silver interlayers. The microstructure and the composition of welded joints were characterized by scanning electron microscopy, X-ray diffraction, and energy-dipersive spectrometry. The mechanical properties of welded joints were evaluated by tensile strength tests. The results indicated that Ag thickness has great effects on the weld appearance, microstructure, and mechanical properties of electron beam-welded joints. In case of 0.3 and 0.4 mm thickness of Ag interlayers, a considerable part of 4J29 and TC4 melts and a large amount of Fe, Ti, and Ni elements diffuse into the molten pool forming intermetallic compounds (IMCs) such as TiFe₂, NiTi, and FeTi. In case of 0.6 mm thickness of Ag interlayer, the welded joint exhibits brazing characteristics with little IMCs near the fusion line of 4J29 Kovar alloy side. When the thickness of the Ag interlayer increases to 0.8 mm, the diffusion of Ti and Fe elements is completely inhibited by Ag. As the thickness of the Ag interlayer increases from 0.3 to 0.8 mm, the tensile strength of the welded sample shows a phenomenon that first rises and then falls, and the largest tensile strength is 243 MPa.

Si₃N₄ and Invar alloy brazed joints were achieved using two types of Ag-based interlayers: a Ag–Cu–In–Ti foil and a Ag–Cu–In–Ti/Cu/Ag–Cu multi-interlayer. The results showed that when only using a single Ag–Cu–In–Ti filler, the wave-shaped Fe₂Ti + Ni₃Ti intermetallic compounds are concentrated in the middle of the brazing seam. When adding Cu as the interlayer, the dissolution of the Cu interlayer formed a large number of Cu(s,s) blocks of different sizes in the brazing seam, which hindered the concentrated distribution of Fe₂Ti + Ni₃Ti intermetallic compounds in the brazing seam. As a result, Fe₂Ti and Ni₃Ti were dispersedly distributed in the brazing seam, increasing the shear strength of the brazed joint. The shear strength of brazed joints was increased by 82 % compared to joints brazed with a single Ag–Cu–In–Ti filler when the Cu interlayer was added.

High-speed digital microsystems has emerged as one of the most important solutions for improving system performance, bandwidth, and power consumption. Based on mature micro-system processing technology, a material extraction approach for silicon interposer applied for high-speed digital microsystems was presented in order to obtain frequency-dependent precise material parameters. By combining microwave theory and mathematical model of iterative algorithm, the dielectric constant (Dk) and the dissipation factor (Df) of polyimide dielectric layer is acquired, which minimizes testing costs and streamlines testing process. The method is based on two-port transmission/reflection measurements. Vector Network Analyzer (VNA) is used to extract the scattering parameters with an extraction range of 1 MHz to 10 GHz. The algorithm is programmed using MATLAB. The observed Dk values at 2 GHz, 6 GHz, 8 GHz, and 10 GHz are, respectively, 3.22, 3.04, 2.96, 3.03, and 2.91, while the corresponding Df values are 0.021, 0.025, 0.026, 0.026, and 0.024. Finally, the complex permittivity derived is simulated and analyzed using Ansys HFSS. The results verify the validity of the theoretical method and proves that the values of the complex permittivity obtained by the method in this paper are reliable.