Mask blank, transfer mask, and methods of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9470971-B2
Application number	US-201314391345-A
Country	US
Kind code	B2
Filing date	May 9, 2013
Priority date	May 16, 2012
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.

First claim

The invention claimed is:

1. A mask blank, comprising:
a transparent substrate having a main surface; and
a thin film for forming a transfer pattern on the main surface of the transparent substrate;
wherein the thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen,
wherein the thin film has as a surface layer an oxide layer having an oxygen content higher than an oxygen content of the thin film of a region excluding the surface layer,
wherein the thin film is formed so that a thickness of an outer peripheral portion is greater than a thickness of a central portion on a side of the main surface, and
wherein the oxide layer is formed so that a thickness of the outer peripheral portion is greater than a thickness of the central portion on the side of the main surface.

2. The mask blank according to claim 1 , wherein the thin film is a semitransmissive film having a transmittance of 1% or more for exposure light.

3. The mask blank according to claim 2 , wherein the thin film is formed so that an in-plane distribution of the transmittance is in a range of 0.6%.

4. The mask blank according to claim 1 , wherein the thin film is a halftone phase shift film having a transmittance of 1% or more for exposure light and adapted to produce a predetermined phase difference between exposure light transmitted through the thin film and exposure light transmitted in air for a distance equal to a thickness of the thin film.

5. The mask blank according to claim 4 , wherein the thin film is formed so that an in-plane distribution of the phase difference is in a range of 4 degrees.

6. The mask blank according to claim 4 , wherein the thin film is formed so that an in-plane distribution of the transmittance is in a range of 0.6%.

7. A transfer mask, comprising:
the transfer pattern formed in the thin film of the mask blank according to claim 1 .

Assignees

• Hoya Corp

Inventors

• Umezawa Teiichiro
• Ishiyama Masafumi

Classifications

• G03F1/26 Primary

  Phase shift masks [PSM]; PSM blanks; Preparation thereof · CPC title

• C23C14/0036

  Reactive sputtering · CPC title

• C23C14/225

  Oblique incidence of vaporised material on substrate · CPC title

• C23C14/0676

  Oxynitrides · CPC title

• G03F1/32 Primary

  Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof · CPC title