Measurements of mechanical properties of microfabricated thin films

Mechanical properties of titanium thin films of 0.5 mu m thickness, microfabricated by magnetron sputtering, were measured by using a novel tensile machine. These thin films are difficult to handle because they are markedly fragile, so the thin film specimens were fabricated by using semiconductor manufacturing technology in silicon frames to protect them. The test section of these specimens was 300 mu m in width and 1.4 mm in length. By gripping the thin film specimen with a new device using a micrometer, it could be mounted on the tensile machine easily. The stress-strain diagrams of thin films were measured continuously in the atmosphere at room temperature. Tensile tests were conducted on specimens of 1.0 to 1.4 mm gauge length in order to examine the effect of gauge length on the measurements of mechanical properties. Measurements of Young's modulus, tensile strength and breaking elongation were independent of gauge length for our range of measurements. The experimental results indicated that the titanium thin films had a smaller breaking elongation although they had a larger tensile strength than bulk pure titanium.