Browse Prior Art Database

New method for chrome reticle inspection

IP.com Disclosure Number: IPCOM000017621D
Original Publication Date: 2001-Apr-01
Included in the Prior Art Database: 2003-Jul-23
Document File: 1 page(s) / 13K

Publishing Venue

Siemens

Related People

Thorsten Schedel: AUTHOR [+2]

Abstract

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.

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Information / Kommunikation

New method for chrome reticle inspection

Idee: Thorsten Schedel, Dresden; John Maltabes, Dresden

Reticles consist of patterns to be printed on wafers. Historically chrome has been used forblocking unwanted radiation, however any material that has blocking properties for UV, deep UVand shorter wavelengths can be used.

If the density of the blocking material is insufficient light goes through the reticle ( mask) and isstructuring the resist in an undesired area. This may be caused by quality variations of the materialitself ( blanks ) or by process variations during reticle manufacturing. These reticle defects printghost patterns in the resist. In future the resist thickness will be further reduced and such patternscaused by chrome leakage will show more influence compared to technologies with a higher resistthickness.

Therefore a new method was developed in order to inspect reticles with an easy test which couldbe done by operators in special time periods in order to also cover migration effects.

The method proposed takes advantage of the non-patterned area of a reticle that can be bladeddown to expose only chrome on the wafer surface. An exposure matrix would then be run,exposing the wafer to up to 100 times the nominal dose. After exposure and development theresist on the wafer should show no loss of thickness. This could be inspected by a film thicknessmeasurement tool using an automated technique. If there is a loss of film thickn...