Method for adjusting spectrum width of narrow-band laser

Abstract

An upper limit and a lower limit are preliminarily set for a spectral line width common to a plurality of narrow-band laser devices. When delivered or subjected to maintenance, the narrow-band laser device is caused to laser oscillate to detect its spectral line width before it is used as a light source for semiconductor exposure. A spectral line width adjustment unit provided in the narrow-band laser device is adjusted so that the spectral line width assumes a value between the upper limit and the lower limit. The present invention is able to suppress the variation in spectral line width such as E95 bandwidth caused by machine differences during the manufacture of the laser device, or by replacement or maintenance of the laser device, whereby the quality of integrated circuit patterns formed by the semiconductor exposure tool can be stabilized.

1 - 8 . (canceled) 
     
     
         9 . A narrow-band laser device used as a light source for semiconductor exposure, comprising:
 a laser chamber configured to oscillate laser light;   a line narrowing unit arranged on a rear side of the laser chamber and configured to narrow a spectral line width of the laser light output from the laser chamber;   a spectral detecting unit configured to detect the spectral line width; and   a spectral line width adjustment unit configured to adjust the spectral line width;   wherein the spectral line width adjustment unit is arranged on a front side of the laser chamber and has a cylindrical convex lens and a cylindrical concave lens which are arranged on an optical path of the laser light.   
     
     
         10 . The narrow-band laser device according to  claim 9 , wherein the spectral line width adjustment unit adjusts the spectral line width, before a semiconductor exposure, into a value between an upper limit and a lower limit of a spectral line width, which are allowed for the semiconductor exposure and which are common to a plurality of narrow-band laser devices. 
     
     
         11 . A spectral line width adjustment method of adjusting a spectral line width of laser light emitted from a narrow-band laser device used as a light source for semiconductor exposure, comprising:
 oscillating the laser light with the narrow-band laser device;   detecting a spectral line width of the laser light oscillated with the narrow-band laser device; and   adjusting the spectral line width with a spectral line width adjustment unit of the narrow-band laser device;   wherein the spectral line width adjustment unit is arranged on a front side of the laser chamber and has a cylindrical convex lens and a cylindrical concave lens which are arranged on an optical path of the laser light.   
     
     
         12 . The spectral line width adjustment method according to  claim 11 , wherein:
 the method is performed before a semiconductor exposure, and further comprises the step of setting an upper limit and a lower limit of a spectral line width, before said oscillating of the laser light, which are allowed for the semiconductor exposure and which are common to a plurality of narrow-band laser devices; and   said adjusting of the spectral line width adjusts the spectral line width into a value between the upper limit and the lower limit