X-Ray Stress Measurements of Single Crystal in Local Area Using Synchrotron Radiation

X-ray stress measurements in a local area of a single crystal silicon were carried out using synchrotron radiation. In the experiment, the beam line 3A (BL3A) in the Photon Factory of the High Energy Accelerator Research Organization, Tsukuba, Japan, was utilized. The χψ-oscillation method was used as the oscillation method of a specimen for detecting a perfect diffraction profile. In the case of using synchrotron radiation, a wavelength can be selected using a monochromater so that the diffraction angle may become high angle where the highly-accurate strain measurement is possible. Therefore, accuracy of the stress measurement is improved more than using characteristic X-rays. The stresses in three steps were applied on a specimen using a four-point bending device. The diffraction angles of three different diffraction planes were measured in each step using the φ50μm collimator, and the stresses were calculated from the peak shift. The measured stresses agreed well with the applied stresses evaluated using a strain gage. Also, the stress distribution near the edge of the circular hole of the diameter of 400μm which was made on a single crystal silicon was measured using the φ30μm collimator. The stress was applied using a four-point bending device, and the stresses were measured at five points from the edge of the circular hole to 240μm. The measured stress distributions agreed with the FEM result. However it is necessary that the beam size is more decreased in order to obtain the stress distributions more accurately.