Abstract
Estimation methods for the creep properties by measuring the micro size deformation is required for finite element method (FEM) analysis considering the creep deformation of the solder joint in-situ. The indentation creep test is one of the effective methods to directly evaluate the creep deformation of solder joint. However, the indentation test cannot give the same creep properties as the creep properties obtained by the uniaxial creep tests using a bulk specimen. The authors proposed an indentation test conducted under a constant depth to determine a suitable reference area, which leads to the same creep characteristics as those obtained by the uniaxial creep test. One of the remaining problems of the indentation test is the reference area cannot be determined without the creep data obtained by the uniaxial creep test. In this paper, a method to determine the reference area without the uniaxial creep tests using a bulk specimen is proposed. For the determination of the new reference area, numerical indentation tests under a constant depth process for four kinds of solder alloys were conducted by FEM. The numerical simulation showed that the reference area obtained considering the distribution of the principal stress gives the almost same creep characteristic as that obtained by the uniaxial creep using bulk specimens.
