A new three-axis inertial switch is proposed. The triangle-structured movable electrode is designed to improve the inertial switch’s dynamic response performance, especially the movable electrode’s dynamic stability performance. The static mechanical analysis indicated that the displacement of the movable electrode to the fixed electrode in the sensitive direction is the minimum when the acceleration is applied to this designed inertial switch. The dynamic simulation analysis showed that the threshold of the designed inertial is about 235 g. The threshold in the non-sensitive direction is about 240 g, 270 g, 300 g, and 350 g when the directions of applied acceleration deviate 15°, 30°, 45°, and 60° from the sensitive direction, respectively. These results indicated that the designed inertial could resist the impact in non-sensitive directions and improve the stability in sensitive directions. The prototype of the inertial switch was fabricated and tested successfully. The testing results indicate that the threshold of the fabricated inertial switch is about 219 g. The test results verify the dynamic stability performance of the designed inertial switch.

A compact antenna is designed as a CPW fed monopole with T shape, Y shape and meander shape. Based on the larger range of the adjustable parameters of this antenna, the optimized antenna is relative compact with high radiation performance. In order to enhance the radiation performance of the antenna-in-package, an antenna-in-package based on through-silicon-interposer with embedded air cavity and polyimide dielectric micro-substrate is proposed. The shielding structure is covered among the RF device to reduce the influence of the electromagnetic interference of the AiP. Under this design, the radiant efficiency is enhanced more than 10% compared with the Si substrate antenna within large bandwidth and gain.

The in situ measurement of TSVs deformation at different temperature is meaningful for learning more about the thermal deformation schemes of 3D TSVs in the microelectronic devices. An efficient and smart hotplate based on sheet resistance is designed for offering more heat, producing a uniform temperature distribution, relieving thermal stress and heat concentration issues, and reducing room space, which was optimized by the finite element method (FEM). The fabricated hotplate is efficient and smart (2.5 cm x 2.0 cm x 0.5 cm) enough to be located in the limited space during measuring. The thermal infrared imager was employed as the temperature sensor for monitoring the temperature distribution of TSVs sample. The 3D profilometry was adopted as the observer for TSVs profiles survey. The in situ 2D top surface profiles and 3D displacement profiles of TSVs sample at the different temperature were measured by 3D profilometer. The in situ average relative deformation and effective plastic deformation of the TSV sample were measured. With optical measurement method, 3D profilometry, the TSV sample can be tested repeatedly.

Two-step direct current electroplating was used to fabricate copper microcylinders with a 50 m diameter and 150 m depth. The microstructure was characterised by electron back scattering detection. Twin boundaries appeared and the twin quantity depended on the current density. Near the edge (2 mA/cm(2)), the grain size was large (approximate to 2 m) and many twins existed, while the size was small (approximate to 0.5 m) and few twins occurred in the middle (4 mA/cm(2)). The hardness was measured by nano-indentation technique. The results showed that the hardness (2.7 GPa) at the edge of the sample was higher than that in the middle (2.2 GPa), which was probably enhanced by twins. The hardness of annealed sample was about 1.7 Gpa, which was independent of the position.

Through-silicon via (TSV) technology is the heart of 3D integration technology. An approach was proposed to simplify the integrated process flows. Dry film photoresist was introduced in the through via filling process. Cu-TSVs and Cu-pads were formed simultaneously through the electroplating process, which diminished the interface between Cu-TSVs and Cu-pads. This approach simplified the integrated process flows, enhanced the reliability, and lowered the costs dramatically compared with the most preferred TSV fabrication method in the industry today, which would have a broad application in the 3D integration industry.

Graphene has a high thermal conductivity, electrical conductivity and outstanding mechanical properties,which is considered as the good reinforcement material in the composites. In the reported literatures, graphene oxide was generally used as the precursor of reinforcement to electrodeposit the composite film, then followed by the reduction of graphene oxide to graphene. In this paper, the graphene-Cu composite film was directly electrodeposited from the electrolyte containing multilayer graphene nanosheets through pulse electrodeposition under ultrasonic stirring, which was compatible with MEMS process. The experimental results indicated that the graphene-Cu composite film in this study had much less defects density than that in the reported literature. Micromachining technology is used to test the thermal conductivity, electrical resistivity and mechanical property of the composite film. Compared to pure Cu film, the mechanical property of the graphene-Cu composite film was remarkably increased while the electrical property and thermal property were comparable.

A laterally-driven inertial micro-switch was designed and fabricated using surface micromachining technology. The dynamic response process was simulated by ANSYS software, which revealed the vibration process of movable electrode when the proof mass is shocked by acceleration in sensitive direction. The test results of fabricated inertial micro-switches with and without anti-shock beams indicated that the contact process of micro-switch with anti-shock beams is more reliable than the one without anti-shock beams. The test results indicated that three contact signals had been observed in the contact process of the inertial switch without anti-shock beams, and only one contact signal in the inertial switch with anti-shock beams, which demonstrated that the anti-shock beams can effectively constrain the vibration in non-sensitive direction.

In this paper, the through silicon via (TSV) blind holes with a diameter of 50μm and a depth of 150μm were prepared by MEMS micromachining technology. The Cu micro-cylinders (Cu-TSVs) were obtained by electrodepositing Cu in the blind holes using a direct current power. The mechanical properties of Cu-TSVs were measured using a self-made micro-compression system. The effect of current density on the mechanical property of Cu-TSVs was investigated. The experimental results indicated that when the current density increased from 1mA/cm2 to 3mA/cm2, the yield strength increased from 135.5MPa to 177.6MPa. However, when the current density further increased to 6mA/cm2 and 9mA/cm2, the yield strength decreased to 159.8MPa and 119.3MPa, respectively. Although it can improve the plating efficiency, the high current density led to the low yield strength. EBSD and XPS techniques were used to characterize the microstructure and impurities of Cu-TSVs. The grain size, grain boundary and grain orientation of Cu-TSVs electroplated at different current density were analyzed to discuss the mechanism.

A micro-compression test method was presented to evaluate the mechanical property of the TSV-Cu micropillar in this paper. Firstly, the test sample containing TSV-Cu micropillar was prepared by MEMS micromachining technology. Then, the mechanical property of TSV-Cu micropillar was measured by a self-made micro-compression system. Finally, the effect of thermal treatment on the mechanical property of TSV-Cu micropillar was studied. The experimental results showed that the average yield strength ( σ 0.2 ) of the TSV-Cu micropillar was 167 MPa. But it decreased to 137 MPa after being thermally treated at 400°C for 1 hour, which was probably due to the increased grain size of Cu.

The Cu specimens were fabricated by the UV-LIGA process using the electrodeposition bath for through-silicon-via (TSV) filling. Mechanical properties of the Cu specimens annealed at different temperatures were investigated by a uniaxial tensile test. The results indicated that the yield strength and breaking strength of as-deposited Cu specimens were higher than that of the bulk Cu, while the elastic modulus was lower than that of the bulk Cu. The elastic modulus, yield strength and breaking strength of Cu specimens decreased with the increase of the annealing temperature. When the annealing temperature was 400^oC, the elastic modulus decreased from 95 to 69GPa, the yield strength decreased from 314 to 202MPa, and the breaking strength decreased from 367 to 290MPa, respectively. In contrast, the ultimate strain increased with increasing the annealing temperature. The surface morphology, fractography and crystal structure of the Cu specimens were characterized by SEM, TEM and XRD methods. The results indicated that the particle size increased with the increase of the annealing temperature, which contributed to the decrease of the yield strength and breaking strength according to the Hall-Petch law. The XRD results indicated that as-deposited Cu specimens had a preferred orientation in (220) plane, but (311) plane became the preferred orientation with increasing the temperature. This probably contributed to the decrease of the elastic modulus with increasing the temperature.

This paper puts forward an in-situ testing method for the mechanical properties of TSV copper pillar by using micro-compression experiment. The sample for micro-compression test is prepared by the processes as follows: (a) etching TSV with deep reactive ion etching (DRIE), (b) sputtering a layer of Ti/Cu as the seed layer, (c) TSV copper plating technology, and (d) corroding the silicon to obtain the final specimen. The micro compression test is done with a micro-compression system, consisting of a three-dimensional adjustable stage, a microscope, a force sensor, and a piezoelectric motor. The experimental results show that the platform can test TSV copper pillar’s stress, the accuracy is reached mN. The yield strength of TSV copper pillar is about 199.89 MPa.

The Cu specimens were fabricated by the UV-LIGA process using the electrodeposition bath for through-silicon-via (TSV) filling. Mechanical property of th e Cu specimens was investigated by a uniaxial tensile test. The elastic modulus, yield strength, breaking stre ngth and ultimate strain are 95GPa, 314MPa, 367MPa and 12.4%, respectively. The results indicated that the yield strength and breaking strength of as-deposited Cu specimens were higher than that of the bulk Cu, while the elastic modulus was lower than that of the bulk Cu. The elastic modulus of C u thin film in surface and section are 115.7GPa and 105.4GPa measured by nanoindentation, respectively. This difference is caused by the difference of the grain orientation between the surface and section of Cu thin film.

The miniaturization trend of microelectric products gives birth to 3D stacking of chips, which is realized by using TSV （through silicon via） technique. A novel micro-tensile specimen of the uniaxial micro-tensile test for measuring the mechanical properties of Cu-TSV is proposed. Finite-Element Method （FEM） has been used to optimize the design of the supporting frame of the sample with a Cu-TSV thin film, which can effectively reduce the damage ratio of the sample during operations. The surface-treated Ti seed layer has substituted for the traditional Cr/Cu seed layer to reduce the stress concentration and prevent the specimen from alkali corrosion when etching the seed layer. The samples have been tested by the uniaxial micro-tensile system to obtain the mechanical properties of the Cu-TSV thin film. The measured Young＇s modulus and the ultimate tensile strength of Cu-TSV is 25.4--32. 9 GPa and 574--764 MPa, respectively.

A novel test sample with a micro scale free-standing specimen of Cu-TSV used for uniaxial micro-tensile test is presented in this paper. Design of a deformation-buffer reticular supporting frame of the test sample effectively reduces the deformation of Cu-TSV thin film during clamping operation. The stress resulting from electrodepositon process is minimized by fabricating Cu-TSV thin film on surface-treated titanium seed layer. The process of titanium seed layer avoids alkali corrosion and simplifies fabrication procedure compared with that of the traditional Cr/Cu seed layer. Both finite-element method (FEM) simulation and experimental results indicates the advantages of this new design. The test sample fabricated by the optimized process well coordinates with our micro-tensile system. The Young's modulus and the ultimate tensile strength of tested Cu-TSV thin film measured by our micro-tensile system are 25.4~32.9GPa and 574~764MPa, respectively.