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Cleaning Particle Contamination from Photo Masks

IP.com Disclosure Number: IPCOM000084993D
Publication Date: 2005-Mar-02
Document File: 2 page(s) / 27K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that removes particles from critical areas of photo masks; the disclosed method is particularly useful in extreme ultraviolet lithography (EUVL), where photo masks are not protected by a pellicle. Benefits include minimizing contact with the entire mask.

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Cleaning Particle Contamination from Photo Masks

Disclosed is a method that removes particles from critical areas of photo masks; the disclosed method is particularly useful in extreme ultraviolet lithography (EUVL), where photo masks are not protected by a pellicle. Benefits include minimizing contact with the entire mask.

Background

Cleaning particle defects from high-end and a EUVL photo mask is essential. This cleaning is particularly important for EUVL photo masks, since particles currently found in litho fabrication require the mask to be shipped back to the mask shop for cleaning and inspection.

Currently, photo masks are cleaned using a wet chemical process. The particles are either washed away or dissolved chemically. After cleaning, the mask is re-inspected because pattern removal, lift, and pinhole defects are often the result of repeated cleanings. This solution requires a lengthy return to the mask shop and increased downtime for wafer fabrication.

General Description

In the disclosed method, a defect is found by conventional means, and then an Atomic Force Microscope is used to map the defect and the nearby pattern. Using the Atomic Force Microscope tip, or a specially modified tip, the defect is moved to a non-critical area (e.g. against the pattern), or removed from the surface of the photo mask. Cleaning the Atomic Force Microscope tip is done in the same manner as cleaning the contact printing masks; the tip is pushed into a sticky polymer resin to remove t...