This paper presents the results of tensile and high cycle fatigue tests for copper thin film. Copper films coated by Sn are often used in various electro devices. Especially, when the film is used in tape carrier package (TCP), the film is repeatedly exposed to mechanical or(and) thermal stresses which results often in the failure of the component. Therefore, to guarantee the reliability of the electrical devices using a film, tensile and fatigue characteristics of the film are important. In this study, to obtain the tensile and fatigue characteristics of the film, the specimen was fabricated by an etching process to make a smooth specimen of 2000 lm width, 8000 lm length and 15.26 lm thickness. The tensile and high cycle fatigue tests were performed with the specimen using the test machine developed by the authors. These specimens had measured values of Young's modulus (72 GPa) and a 0.2 % offset yield and an ultimate strength of 358 MPa and 462 MPa, respectively. A closed-loop feedback control of the magnetic-electric actuator allowed loadcontrolled fatigue tests with 20 Hz frequency, in ambient environment and at two levels of mean stresses. The fatigue strength coefficient and exponent at 0.5 times of the ultimate tensile strength were 431 MPa and -0.0843, respectively. The fatigue strength coefficient and exponent at 0.6 times of the ultimate tensile strength were 371 MPa and -0.0923, respectively. The Goodman method is recommended when the fatigue life of thin film with mean stress will be estimated. The fatigue strength coefficient and exponent of copper thin film modified using Goodman method were 910 MPa and -0.0896, respectively.

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The influence of fabrication on the tensile and fatigue behavior of copper films manufactured by 3 kinds of fabrication methods was investigated. The tensile and high cycle fatigue tests were performed using the test machine developed by authors. Young's moduli (72, 71 and 69 GPa, respectively) are lower than the literature values (108-145 GPa), while the yield strengths were as high as 358, 350 and 346 MPa, respectively and the ultimate strengths as 462, 456 and 446 MPa, respectively. There is not much difference in the tensile properties of the 3 kinds of films. There is little difference in the fatigue properties of the 3 kinds of films but one of them has shorter fatigue life than others in high cycle region and longer fatigue life than others in low cycle region.

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