| 摘要 |
PURPOSE:To position a line of chips and the moving direction of a stage parallel to each other with accuracy and facility by a method wherein the movement of semiconductor devices being successively manufactured is made to look roughly immobile by regularly interrupting the light beam thrown upon a moving wafer or by regulary interrupting the reflection from the wafer. CONSTITUTION:For the satisfaction of an equation theta=0, a light beam, serving the operator watching the pattern on a wafer on a stage moving back and forth by means of a microscope or the like, is regularly interrupted at frequency T that equals Nd/v, where d is the repetition frequency of chips 22, v the traveling speed of the stage, and N a natural number. When a traveling wafer is exposed to a light beam switched off and on at frequency T, the wafer seems to the operator as if occupying the same position every time the light is switched on, provided theta equals 0. When the frequency is so chosen somewhere between several tens to several 100mm. per second as to fall in the range of the afterimage phenomenon, the chips 22 as the operator watches them seem to be immobile. When theta-, the chips 22 seem to move slowly up and down as the stage reciprocates. It is easy to adjust and realize theta=0. |
