In this paper, we present the development of a low cost chip/wafer bumping technique for flip chip assembly and microelectromechanical systems integration using a bump transfer approach. In this method, high melting temperature bumps such as copper, nickel, and gold bumps are fabricated on a lowcost, flexible carrier and then transferred onto the target chip/wafer/board for flip chip assembly. The aluminum pads on test chips were remetallized with electroless nickel and gold layers to facilitate the bonding of bumps to the chips using thermocompression bonding. Parallel bonding and transfer of bumps has been achieved. Thermal cycling and bump shear test showed that reliable bonding was obtained between the bumps and the pads. Surface study using laser ionization mass analysis found no traces of of the polymer carrier on the surface of the bumps on the test chip after the completion of the bump transfer process.

通过摩擦学系统分析，指出了目前人工关节无润滑系统的结构缺陷，为解决此缺陷提出一种包括生物浓液、人工关节摩擦配副和仿生关节囊的新型人工仿生关节学系统结构，并对系统设计以及其改善现有人工关节系统润滑的潜在优越进行了讨论，采用销-盘摩擦试验机对影响人工关节仿生润滑系统摩擦学性能的滑液进行了模拟试验前的快事速初步评价，结果表明，滑液可显著改善人工关节副的摩擦学特性，但其效果同系统条件其结构无素有关，在研记生滑液和设计其摩擦学特性模拟试验方法时，必须结合这些影响因素进行设计和试验。

We prostheses that omit many functions of the lubricant and the joint capsule. The new structure is composed of three components: lubricant, artificial joint and artificial joint capsule. The lubricant sealed in the capsule can not only reduce the wear of the artificial joint but also prevents the wear particles leaking into the body. So unexpected reactions between the wear particles and body can be avoided completely. A three-dimensional (3-D) finite element analysis (FEA) model was created for a bionic knee joint with capsule. The stresses and their distribution in the artificial capsule were simulated with different thickness, loadings, and flexion angles. The results show that the maximum stress occurs in the area between the artificial joint and the capsule. The effects of capsule thickness and the angles of flexion on stress are discussed in detail.

Flip chip joining technology using anisotropically conductive films (ACFs) has become an attractive technique for electronic packaging. However, several factors have hindered the wide spread use of this technology. Along with the reliability issue, these factors also include the low availability and high cost of the bumped wafers. This paper introduces the feasibilities of using unbumped die with respect to ACF joints for flip-chip-on-flex (FCOF) assemblies. The unbumped dies contain only bare aluminum pads. Untill now the performance of ACF to Al metallization is a controversial issue from the published reports. In this study, two different test vehicles were used to study contact resistance and adhesion performance. Reliability of contact resistance for ACF joints with the unbumped dies was investigated in terms of varying the thickness of the Al pads. Adhesion performance of ACF to the Al metallization was compared with the adhesion performance of ACF to a glass substrate using the same ACF and the same bonding parameters. FCOF assemblies containing dies with thinner aluminum pads showed lower initial contact resistance and a lower rate of increment during accelerated aging tests. Three factors were considered as the potential causes for the above results: (1) lower concentration of aluminum oxide on the thin Al pad, (2) larger contact area per deformed particle with Au/Ni/Cu electrode for the interconnection of thin Al pad and (3) lower concentration of the defects in the thin Al pad. Contact resistance was found to increase during accelerated testing because of aluminum oxide formation on top of the pads. Contrary to the usual expectation, adhesion strength of ACF with the Al metallization was increased during 60C/95% RH testing. After 500 h of such moisture-soak testing, the adhesion strength becomes 3 times the initial value. The change in chemical state on the aluminum surface is considered to be responsible for higher adhesion strength. It is proposed that oxidation of Al surface due to diffused moisture and the new chemical bond formation at the adhesives/aluminum interface are the key reasons for good adhesion reliability.

基于仿生人工关节结构，利用连杆机构模似关节弯曲/拉伸运动方式建立了仿生人工关节评价装置，同时对以小牛血清作为润滑介质的氧化锆-超高子量聚乙烯（ZrO-UHMWPE）人工关节配副进行磨损性能测试，结果表明：所建立的装置不仅可以加速考察人工关节配副的磨损特性，还能够加速评价仿生关节囊的动态疲劳性能，同时实现转速、载荷以及运动角度等参数可调并具有较强可操作性；UHMWPE 的磨损量与运动周期近似呈线性关系，UHMWPE 的体积磨损率相对稳定，约为70～80mm3/10周期，且具有较好的重复性与可靠性。