Method for Exposing an Area on a Substrate to a Beam and Photolithographic System

Abstract

Embodiments of the invention describe a method for exposing an area on a substrate to a beam. The method includes adjusting a focus offset of the beam with respect to the area on the substrate, tilting the beam or tilting the substrate, and exposing the area on the substrate with the beam, thereby generating locations within the area exposed with different foci. Furthermore embodiments describe computer programs for controlling a photolithographic system to do the same and a photolithographic system for doing the same.

What is claimed is: 
     
         1 . A computer program comprising machine readable instructions for controlling a photolithographic system to exposure an area on a substrate to a beam by adjusting a focus offset of the beam with respect to the area on the substrate;
 tilting the beam or tilting the substrate; and   exposing the area on the substrate with the beam, thereby generating locations within the area exposed with different foci.   
     
     
         2 . A computer program comprising machine readable instructions for exposing different measurement points in one focus exposure field of a focus exposure matrix on a wafer covered with photo resist, by adjusting a focus offset of a photolithographic beam with respect to the focus exposure field on the wafer covered with photo resist;
 tilting the photolithographic beam or tilting the wafer relative to the photolithographic beam;   setting a dose for exposing the focus exposure field on the wafer with the photolithographic beam; and   exposing the focus exposure field on the wafer with the photolithographic beam, thereby generating different measurement points within the focus exposure field exposed with different foci.   
     
     
         3 . A photolithographic system comprising:
 a beam source configured to emit a beam of an adjustable intensity for exposing a first area on a substrate;   a shutter, configured to block the beam or let the beam through, so that an exposure time of the first area on the substrate with the beam is controllable;   a lens-system, configured to image the beam on the first area on the substrate;   a mask holder, configured to support a mask so that a pattern on the mask can be transferred onto the first area on the substrate;   a chuck, configured to move and support the substrate, fixable thereon; and   a control unit configured to control a focus offset, a tilt angle of the beam or a tilt angle of the substrate and an exposure dose for the first area on the substrate to be exposed so that locations within the pattern, which is transferred onto the first area, are exposed with different foci.   
     
     
         4 . The photolithographic system according to  claim 3 , wherein the control unit is further configured to move the chuck to a second position so that an exposure of a second area on the substrate to be exposed is repeatable, wherein adjusting, tilting and exposing is repeated for the second area, with one of the focus offset, tilt angle and dose being modified, when compared to exposing the first area on the substrate. 
     
     
         5 . The photolithographic system according to  3 , wherein the control unit is further configured to move the chuck with a substrate fixable thereon, to a plurality of areas arranged in a focus exposure matrix on the substrate, wherein adjusting, tilting and exposing is repeated for each area of the focus exposure matrix, with one of the focus offset, the tilt angle and the dose of the beam being modified, when compared to other areas. 
     
     
         6 . The photolithographic system according to  3 , wherein the control unit is further configured to move the chuck with a substrate fixable thereon, to a plurality of areas arranged in a focus exposure matrix on the substrate, wherein adjusting, tilting and exposing is repeated for each area of the focus exposure matrix, with at least one area of the focus exposure matrix, with all of the focus offset, the tilt angle and the dose of the beam being modified, when compared to other areas of the focus exposure matrix.