| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lower chuck pad which is good in suction holding force, and proof against adhesion of impurities, an abrasive, etc. to a front surface thereof. <P>SOLUTION: The lower chuck pad is formed by arranging an adhesive layer on one surface of a lower chuck pad main body having air permeation holes penetrating through front and rear surfaces thereof. The lower chuck pad main body is made of extended porous polytetrafluoroethylene (ePTFE). The ePTFE is excellent in elasticity, water repellent, and hardly adsorb metallic ions and other impurities to which a silicon wafer is vulnerable, to thereby provide the lower chuck pad good in suction holding force and preventing impurities from adhering to the front surface thereof. Further since the lower chuck pad main body is made of ePTFE, it is good at chemical resistance against an acid, an alkali, etc., and free from the risk of abrasion even when an abrasive is employed. <P>COPYRIGHT: (C)2008,JPO&INPIT |
