Lithographic apparatus and method of manufacturing an electrostatic clamp for a lithographic apparatus

Abstract

The invention relates to a method of manufacturing an electrostatic clamp configured to electrostatically clamp an article to an article support in a lithographic apparatus. The method includes providing a first layer of material, etching a recess in the first layer of material, and disposing an electrode in the recess of the first layer of material.

1 . A method of manufacturing an electrostatic clamp configured to electrostatically clamp an article to an article support in a lithographic apparatus, the method comprising: 
 providing a first layer of material;    etching a recess in the first layer of material; and    disposing an electrode in the recess of the first layer of material.    
   
   
       2 . A method according to  claim 1 , further comprising disposing a mask on a surface of the first layer of material, wherein the mask defines a shape of an electrode to be deposited in the first layer of material.  
   
   
       3 . A method according to  claim 1 , wherein the recess etched in the first layer of material has a depth approximately the same as the thickness of the electrode to be disposed in the first layer.  
   
   
       4 . A method according to  claim 2 , further comprising providing a coating of an electrode material on an etched surface to form the electrode and to cover the mask, wherein the coating has a thickness approximately the same as the thickness of the layer etched from the mask bearing surface.  
   
   
       5 . A method according to  claim 1 , wherein the first layer of material comprises a dielectric or semi-dielectric layer.  
   
   
       6 . A method according to  claim 3 , further comprising removing the mask from the first dielectric or semi-dielectric layer.  
   
   
       7 . A method according to  claim 1 , further comprising bonding the first layer of material in which the electrode is formed to a second layer of material to form a stack.  
   
   
       8 . A method according to  claim 7 , wherein the bonding comprises anodic bonding.  
   
   
       9 . A method according to  claim 4 , wherein said providing the coating comprises using a sputtering process, chemical vapor deposition process, or a combination thereof.  
   
   
       10 . A method according to  claim 1 , wherein disposing the electrode comprises disposing first and second electrode portions on the layer of material.  
   
   
       11 . A method according to  claim 1 , further comprising fusing the first layer of material in which the electrode is formed to a second layer of material to form a stack.  
   
   
       12 . A method according to  claim 11 , wherein the fusing comprises applying heat to the stack, applying pressure to the stack, or a combination thereof.  
   
   
       13 . A method according to  claim 1 , wherein the first layer comprises an ultra low expansion material, a glass material, a ceramic material, or a combination thereof.  
   
   
       14 . A method according to  claim 13 , wherein the first layer comprises ULE® ultra low expansion material.  
   
   
       15 . A method according to  claim 13 , wherein the first layer comprises ZERODUR® glass ceramic material.  
   
   
       16 . An electrostatic clamp manufactured according to the method of  claim 1 .  
   
   
       17 . A lithographic apparatus comprising an electrostatic clamp according to  claim 16 .  
   
   
       18 . A lithographic apparatus comprising: 
 an article support constructed to support an article in a beam path of a radiation beam;    an electrostatic clamp configured to electrostatically clamp the article against the article support, the electrostatic clamp being provided with a first layer of material and an electrode, the electrode being formed in a recess etched in the first layer of material.    
   
   
       19 . An apparatus according to  claim 18 , wherein the material is a dielectric or semi-dielectric material.  
   
   
       20 . An apparatus according to  claim 18 , wherein the electrode extends in a plane parallel to the clamping surface of the article support on a side opposite to the side of the clamping surface.  
   
   
       21 . An apparatus according to  claim 18 , further comprising a vacuum chamber for providing a vacuum beam path for the beam of radiation, the layer of material and the electrode being configured to reduce contamination of air, other contaminants, or a combination thereof from entering one or more volumes between the electrodes and the layer of material.  
   
   
       22 . An apparatus according to  claim 18 , wherein the electrostatic clamp comprises a second layer of material.  
   
   
       23 . An apparatus according to  claim 18 , wherein the electrode comprises a first portion and a second portion.  
   
   
       24 . An apparatus according to  claim 23 , wherein the electrostatic clamp comprises a second layer of material and the material of the first or the second layer is provided between the first portion and the second portion.  
   
   
       25 . An apparatus according to  claim 23 , wherein the first portion is a first electrode portion and the second portion is a second electrode portion or a shielding electrode portion.  
   
   
       26 . An apparatus according to  claim 25 , further comprising a voltage supply configured to supply a voltage to the first or second electrode portion.  
   
   
       27 . An apparatus according to  claim 25 , wherein the shielding electrode portion is grounded.  
   
   
       28 . An apparatus according to  claim 18 , wherein the material has a dielectric constant between about 1 and about 8 at about 1 MHz.  
   
   
       29 . An apparatus according to  claim 28 , wherein the material is a dielectric material and has a dielectric constant of about 4 at about 1 MHz.  
   
   
       30 . An apparatus according to  claim 28 , wherein the material is a semi-dielectric material and has a dielectric constant of about 8 at about 1 MHz.