| 摘要 |
<p>A wafer mapping system is provided to sense normally wafers loaded into a top end and a bottom end of a wafer cassette by using a moving unit including a stepping motor for generating rotatory power and a ball screw for moving a wafer sensor. A wafer sensor(310) is installed to sense a plurality of wafers which are loaded into a wafer cassette. One or more LM guides(320) are installed vertically to the wafers loaded into the wafer cassette at a position adjacent to the wafer cassette. A moving unit(330) moves a wafer sensor along the LM guide. A control unit(340) outputs control signals to the wafer sensor and the moving unit in order to sense sequentially the wafers loaded into the wafer cassette while the wafer sensor is moved along the LM guides by the moving unit. The wafer sensor includes a photo sensor. The moving unit includes a ball screw(332) to be rotated in order to move the wafer sensor or a block for supporting the wafer sensor, and a stepping motor(334) for generating rotatory power to rotate the ball screw according to the control signals of the control unit.</p> |
