New method for chrome reticle inspection
Original Publication Date: 2001-Apr-01
Included in the Prior Art Database: 2003-Jul-23
Reticles consist of patterns to be printed on wafers. Historically chrome has been used for blocking unwanted radiation, however any material that has blocking properties for UV, deep UV and shorter wavelengths can be used. If the density of the blocking material is insufficient light goes through the reticle ( mask) and is structuring the resist in an undesired area. This may be caused by quality variations of the material itself ( blanks ) or by process variations during reticle manufacturing. These reticle defects print ghost patterns in the resist. In future the resist thickness will be further reduced and such patterns caused by chrome leakage will show more influence compared to technologies with a higher resist thickness.