Three dimensional micro forming of thin film metallic glass cantilevers and its application for micro probes

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1. PurposesIn order to establish the new precision microforming methods of 3D thin film metallic glass (TFMG) cantilevers, this research examined the following items. (1) Fabrication of Pd-based and Zr-based TFMGs by RF-magnetron sputtering and Measurement of physical properties of the TFMGs, (2) Examination of 3D microforming method of TFMGs at the supercooled liquid region and its accuracy as well as repeatability, (3) Application of 3D TFMG cantilevers for micro probes which use in testing equipments of LSI.2. Results(1) Physical properties of the TFMGs are tested. As a consequence, the TFMGs have high elasticity, high strength and a suitable characteristic for a spring material. Pd_<76>Cu_6Si_<18> TFMG for low electrical resistivity is successfully fabricated. Electrical resistivity of the as-sputtered Pd_<76>Cu_6Si_<18> TFMG is 64 μΩcm. When annealed at 633 K for 2700 s, Pd_<76>Cu_6Si_<18> TFMG becomes partially crystallized, and electrical resistivity decreases to 46.5 μΩcm without inducing embrittlement.(2) Micromachining methods for the two- and three-dimensional microstructures of the TFMGs using softening in the SCLR are proposed. High precision bent or 90・ bent beams and 90・ twisted beams are fabricated.(3) Microprobes are fabricated by the above studies. The dimensions of the microprobe are 200μm high, 400μm long, 50μm wide and 5μm thick. The probes achieve less than 1 Ω contact resistance to Al pad and 1mN contact load. Moreover, it became evident that the probes have sufficient durability by three hundreds of thousands touchdown test.3. Future works(1) Developments of new TFMGs, (2) Measurements of TFMG size effect in tensile test and fatigue strength, (3) The application of the 3D microprobes to probe cards.