CPC G03F 7/70708 (2013.01) [G03F 1/66 (2013.01); G03F 7/70916 (2013.01)] | 20 Claims |
1. A method, comprising:
securing a photomask on a bottom surface of an electrostatic chuck;
generating a first voltage at a peripheral area of the bottom surface of the electrostatic chuck to attract a particle onto the peripheral area of the bottom surface of the electrostatic chuck in a direction to the bottom surface of the electrostatic chuck, wherein the peripheral area of the bottom surface of the electrostatic chuck is not directly above the photomask;
after generating the first voltage, generating a second voltage at the peripheral area of the bottom surface of the electrostatic chuck to repulse the particle, wherein the first voltage and the second voltage have opposite electrical properties; and
generating a third voltage, by using a collecting plate, near a sidewall of the photomask to attract the repulsed particle.
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