| 摘要 |
<p>PURPOSE:To chuck a semiconductor wafer with high accuracy by eliminating the influence by dust and by preventing the deformation of the semiconductor wafer. CONSTITUTION:The plurality of suction grooves 4, each having a suction hole 6 on its bottom, are formed concentrically on a suction face 2 and dust adhesion preventing grooves 5 having a width larger than that of the suction groove 4 are concentrically formed on the suction face 2 which are located between the adjacent suction grooves 4 and a vacuum pump 9 is installed for setting the pressure in the suction grooves 4 at a required vacuum pressure through each suction hole 6. By installing a pressure adjustor 12 which adjusts the pressure of the inside of each dust adhesion preventing groove 5 to the required pressure through an air hole made on the bottom of each groove 5, the pressure of the inside of the dust adhesion preventing grooves is made to have such a value that it may not have any influence by suction from the suction grooves or by the width of the dust adhesion preventing grooves.</p> |
