| 摘要 |
PURPOSE:To detect the shape and position of an electrode by projecting a lighting beam from a direction of a Brewster's angle to vertical of the surface of a chip, and generating the maxumum difference in the intensity of a light reflected by the surfaces of a mtal electrode and a semiconductor with a deflector. CONSTITUTION:An optical beam having a wavelength of red color range is generated from a generator 15, and is incident to a GaP chip 10 at a Brewster's angle thetaB. The beam passed through a deflector 18, and the deflected surface becomes parallel to the incident surface. This deflected light is reflected on the surface of the metal electrode, while the incident light to the surface of the GaP chip in which no ohmic meta electrode exists is not reflected at all but passes through the GaP. Accordingly, an image of the electrode incident to an image sensor 16 has extremely high intensity, and the light intensity of the image of the chip is extremely weak. Thus, the image and position of the electrode become extremely good in contrast to the other zone, thereby enabling accurate detection. |
