Electrostatic surface cleaning

Abstract

Embodiments of the present invention generally provide apparatus and methods for cleaning a substrate, such as a mask. One embodiment of the present invention provides an apparatus for cleaning a substrate comprising a substrate support configured to receive and support the substrate, a collecting tip connected with an electrostatic power source, wherein the collecting tip is configured to pickup particles on a surface of the substrate using electrostatic force, and an indexing mechanism configured to provide relative movement between the collecting tip and the substrate support.

1 . An apparatus for cleaning a substrate, comprising:
 a substrate support configured to receive and support the substrate;   a collecting tip connected with an electrostatic power source, wherein the collecting tip is configured to pick up particles on a surface of the substrate using electrostatic force; and   an indexing mechanism configured to provide relative movement between the collecting tip and the substrate support.   
   
   
       2 . The apparatus of  claim 1 , wherein the collecting tip comprises a tapered end pointing at the surface of the substrate. 
   
   
       3 . The apparatus of  claim 2 , wherein the size of the tapered end is determined according to the size of the particles to be picked up. 
   
   
       4 . The apparatus of  claim 1 , wherein the collecting tip is mounted near a moving end of a rotating arm and the indexing mechanism comprises an arm actuator configured to rotate the rotating arm about a fixed end of the rotating arm and to move the collecting tip above the substrate support. 
   
   
       5 . The apparatus of  claim 4 , wherein the indexing mechanism further comprises a support actuator configured to rotate the substrate support about a central axis of the substrate support. 
   
   
       6 . The apparatus of  claim 1 , wherein the indexing mechanism comprises a stage connected to the substrate support, and the stage is configured to move the substrate support along x and y coordinates. 
   
   
       7 . The apparatus of  claim 1 , wherein the electrostatic power source is configured to apply an electrostatic force between about 50 Volt to about 250 Volt to the collecting tip. 
   
   
       8 . The apparatus of  claim 7 , wherein the electrostatic force applied to the collecting tip is between about 50 Volt to about 100 Volt. 
   
   
       9 . An apparatus for removing particles from a substrate, comprising:
 a substrate support configured to receive and support the substrate;   a probe assembly configured to remove particles from the substrate, wherein the probe assembly comprises:
 an arm having a free end and a fixed end, wherein the free end is movably disposed above the substrate support; 
 a collecting tip mounted near the free end of the arm; and 
 an electrostatic power source coupled to the collecting tip, wherein the electrostatic power source is configured to provide an electrostatic force to the collecting tip. 
   
   
   
       10 . The apparatus of  claim 9 , wherein the collecting tip has a tapered end, and a size of the tapered end is determined by the size of the particles to be removed. 
   
   
       11 . The apparatus of  claim 9 , wherein the substrate support is rotatable about a central axis of the substrate support, and the arm is rotatable about the fixed end. 
   
   
       12 . The apparatus of  claim 9 , further comprises an indexing stage coupled to the substrate support, wherein the two dimension stage is configured to move the substrate relative to the probe assembly. 
   
   
       13 . The apparatus of  claim 9 , wherein the electrostatic force is between about 50 volt to about 250 volt. 
   
   
       14 . The apparatus of  claim 9 , wherein the electrostatic force is between about 50 volt to about 100 volt. 
   
   
       15 . The apparatus of  claim 9 , wherein the substrate is a mask used in a lithography process during semiconductor processing. 
   
   
       16 . A method configured for cleaning a substrate, comprising:
 providing a collecting tip configured to pick up particles from the substrate;   applying an electrostatic force to the collecting tip; and   moving the collecting tip towards the particles on the substrate to pick up the particles.   
   
   
       17 . The method of  claim 16 , wherein providing a collecting tip comprises choosing a diameter of the collecting tip according to sizes of the particles to be picked up. 
   
   
       18 . The method of  claim 16 , wherein moving the collecting tip comprises:
 rotating the substrate about a central axis of the substrate while moving the collecting tip across the substrate from the central axis outwards.   
   
   
       19 . The method of  claim 16 , wherein moving the collecting tip comprises:
 scanning the substrate using the collecting tip.   
   
   
       20 . The method of  claim 16 , further comprising, prior to moving the collecting tip, inspecting the substrate to locate the particles. 
   
   
       21 . The method of  claim 16 , further comprising, prior to applying the electrostatic force, performing a wet cleaning to the substrate. 
   
   
       22 . The method of  claim 16 , wherein applying an electrostatic force comprises applying an electrostatic power between about 50 volt to about 250 volt to the collecting tip. 
   
   
       23 . The method of  claim 22 , wherein the electrostatic power is between about 50 volt to about 100 volt.