Patent ID: 7798195

Claim:
A suction unit to hold a plate member by sucking an adhesive sheet, comprising: a table having a face side comprising having a suction face and a support face provided outside the suction face, the suction face being in a round shape with a center thereof; an air groove provided in the table, the air groove sucking air from substantially all area of the suction face; a first groove provided on the suction face, the first groove having a first looped periphery on the suction face to provide a first opening; a second groove provided on the suction face, the second groove having a second looped periphery on the suction face to provide a second opening; a third groove provided on the support face, the third groove having a third looped periphery on the support face to provide a third opening, wherein the first and third grooves are aligned in a concentric manner, a first radius from the center to the first groove being different from a second radius from the center to the third groove, wherein the first groove located under the plate member is filled with a filling member; wherein a plate member with the adhesive sheet is placed on the suction face, wherein the adhesive sheet is larger than the plate member to extend beyond the plate member, wherein a part of the adhesive sheet extended beyond the plate member covers the second or third opening without the filling member, wherein when the air groove sucks air, the adhesive sheet extending beyond the plate member is sucked in the second or third groove without the filling member.