| 摘要 |
PURPOSE:To take in an image without impairing a ball shape even if a foreign matter exists between a ball and image taking optical means and to inspect the ball shape by inspecting the ball by applying a dark field illumination to the ball to be inspected to brightly illuminate the ball. CONSTITUTION:A ball 5a is illuminated at a low angle by a low illumination angle ringlike illuminator. Then, a reflected light on a mirror-surface of a semiconductor chip 1 is not incident to an objective lens 24 but dark-illuminated. However, the reflected light direction on the part of the ball 5a is mostly incident to the lens 24 to brightly illuminate the ball 5a. An aperture diameter of a motor-driven diaphragm 51 is increased to set a shallow focal depth, and a focal distance is set to a surface of the chip 1. Then, since a reflected light from a wire 5 is less, only the ball 5a is brightly illuminated. Accordingly, even if a foreign matter exists between the ball and picture taking optical means, the shape of the ball 5a can be inspected irrespective of the pattern shape, brightness of the surface of the semiconductor. |
