A matched expansion probe card for high temperature LSI testing
This paper describes the fabrication process and mechanical properties of a novel probe card were described. To match the thermal expansion between the probe card and a silicon wafer in wafer-level burn-in test, a Pyrex glass substrate with feedthrough connections was used to support the probes. To make the slantwise probe contactors, spray coating was used to form a uniform photoresist film on a deeply-wet-etched silicon wafer. The fabricated probe card has 13185 p/sup +/ silicon probe contactors at a pitch of 150 /spl mu/m on an area of 44.0 mm /spl times/ 45.7 mm. The rigidity of the probes is approximately 91.45 N/m. The planarity of the probe tips is within /spl plusmn/ 1 /spl mu/m from the base level.
Fabrication technology of CMOS-MEMS probe chip compatible with electroless nickel plating process
In this study, we use the standard TSMC 0.35 μm 2P4M process to design CMOS-MEMS probe chip. MEMS technology involves the following steps such as lithography process, electroless nickel (EN) plating process, grinding process and dry etching process. The probe chip has through silicon via (TSV) package structure, and the combination of CMOS process within the multi-layer interconnections, which could assist the connection between the probes head the external devices, and reduce the difficulty of wiring layout. In addition, passive components or circuits could be integrated with the CMOS chip to improve the frequency bandwidth and measuring quality. So far, MEMS probe exist a shortcomings that are not able to be integrated with the CMOS process, and the testing cost. The finite element method was adapted to design of probe shapes and sizes. The LIGA-like thick photoresist process and EN plating technique was used in this study, Ni-P alloy to increase the thickness of the cantilever probe to strengthen its support strength were also applied. When the probe cantilever through the EN plating of deposition time, the uneven surface was appeared, each layer structure is used by polishing process to achieve the surface coplanarity. Finally, the probes structure were suspended by the dry etching process (RIE, ICP-RIE), and this study successfully fabricated chips forming one of the probe.
Damage initiation and propagation in composite shells subjected to impact
Abstract The paper investigates the impact-induced damage initiation and propagation for laminated composite shells under low-velocity impact. A three-dimensional eight-node non-conforming element is described to analyze interlaminar stress distribution, and progressive failure. The damage analysis is performed by using Tsai–Wu quadratic failure criterion, Tsai’s damage modes and an additional delamination formula at all Gaussian points. The damage modes considered are matrix cracking, fiber breakage and delamination. The progressive failure is expressed by reducing stiffness of the material at all failed Gaussian points. Special attention is centered on curved laminates. Impact energy threshold for the onset of damage and transient damage size are predicted for composite shells. The analyses of the flat and curved laminates are compared for discussing their different damage mechanism. In addition, the influence of the stacking sequence, the thickness and the radius of curvature on damage behavior of composite shells are studied.