Micro tensile test specimens of thin film single crystal silicon for the most useful structural materials in MEMS (Micro Electro Mechanical System) devices were fabricated using SOI (Silicon-on-Insulator) wafers and MEMS processes. Dimensions of micro tensile test specimens were thickness of $7mu extrm{m}$, width of 50~$350mu extrm{m}$, and length of 2mm. Top and bottom silicon were etched using by deep RIE (Reactive Ion Etching). Thin film aluminum markers on testing region of specimens with width of $5mu extrm{m}$, lengths of 30~$180mu extrm{m}$ and thickness of 200 nm for measuring tensile strain were fabricated by aluminum wet etching method. Fabricated side wall angles of aluminum marker were about $45^{circ}~50^{circ}$. He-Ne laser with wavelength of 633nm was used for checking fringed patterns.