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Method for an EUVL attenuated phase-shift mask

IP.com Disclosure Number: IPCOM000132108D
Publication Date: 2005-Dec-01
Document File: 2 page(s) / 35K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an extreme ultraviolet lithography (EUVL) attenuated phase-shift mask. Benefits include improved functionality, improved performance, and improved process simplification.

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Method for an EUVL attenuated phase-shift mask

Disclosed is a method for an extreme ultraviolet lithography (EUVL) attenuated phase-shift mask. Benefits include improved functionality, improved performance, and improved process simplification.

Background

              A phase-shift mask is conventionally achieved by etching selective multilayers. This solution is used to repair defects by shrinking the multilayer over the defect to create an intentional attenuation error to correct a phase error. Additionally, this solution is applied to the creation of intentional phase errors for creating phase shift masks. However, for EUVL, this solution is unacceptable due to oxidation of the molybdenum (Mo) layer exposed to the atmosphere.

      Localized heating is conventionally used to create fiducials, which are not as precise as  creating phase shift masks.

              Conventional transmitted-light attenuated phase-shift contact mask creation includes the following process steps:

1.           Mask pattern is written for the absorber layer.
2.           Absorber layer is etched and processed.

3.           Photoresist layer is deposited.

4.           Steps 1-3 are repeated for an attenuation/phase shift layer.

General description

      The disclosed method is localized heating of the molybdenum and silicon multilayers in a phase-shift mask to produce an intentional phase shift during phase-shift mask production.

      A heat source, such as an electron beam or laser, with a small spot size to shrink the multilayer mirrors is used to create reflective EUVL photomask blanks. The heating is controlled to shrink the multilayer, which produces the phase shift. Some control over att...