# US 2019/0377255 A1 · Chromeless Phase Shift Mask Structure and Process

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- Number: US 2019/0377255 A1
- Document ID: US20190377255A1
- Status: Published application
- Kind: A1
- Application number: 16/548,273
- Filed: 2019-08-22
- Published: 2019-12-12
- Earliest claimed: 2016-08-25
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Yun-Yue Lin; Hsin-Chang Lee
- Web page: https://patentgrep.com/patent/US20190377255A1

## CPC

- G03F 1/26: Phase shift masks [PSM]; PSM blanks; Preparation thereof
- G03F 1/34: Phase-edge PSM, e.g. chromeless PSM; Preparation thereof
- G03F 1/38: Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
- G03F 1/80: Etching
- H10P 30/22: using masks
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure provides a mask. The mask includes a substrate; an etch stop layer disposed on the substrate, wherein the etch stop layer includes at least one of ruthenium oxide, tungsten nitride, and titanium nitride and is doped with at least one of phosphorous (P), calcium (Ca), and sodium (Na); and a material layer disposed on the etch stop layer and patterned to have an opening, wherein the etch stop layer completely covers a portion of the substrate within the opening.

## Claims

### Claim 1

A mask, comprising:
a substrate;
an etch stop layer disposed on the substrate, wherein the etch stop layer includes at least one of ruthenium oxide, tungsten nitride, and titanium nitride and is doped with at least one of phosphorous (P), calcium (Ca), and sodium (Na); and
a material layer disposed on the etch stop layer and patterned to have an opening, wherein the etch stop layer completely covers a portion of the substrate within the opening.

### Claim 2 (depends on 1)

The mask of claim 1, wherein the material layer is designed to provide a phase shift and further designed to provide a transmittance greater than 90% to a light radiation of a lithography process.

### Claim 3 (depends on 2)

The mask of claim 2, wherein the material layer includes a thickness such that the phase shift is substantially 180 degrees.

### Claim 4 (depends on 2)

The mask of claim 2, wherein the material layer is separated from the substrate by the etch stop layer and is designed to provide a transmittance in a range from 90% to 99%.

### Claim 5 (depends on 2)

The mask of claim 2, wherein the transparent substrate includes fused quartz and the material layer includes silicon oxide doped with carbon.

### Claim 6 (depends on 2)

The mask of claim 2, wherein the material layer includes silicon (Si), oxygen (O), carbon (C), nitrogen (N), phosphorous (P), and boron (B).

### Claim 7 (depends on 2)

The mask of claim 2, wherein the material layer includes silicate glass dispersed with chromophore.

### Claim 8 (depends on 2)

The mask of claim 2, wherein the material layer is a sol-gel silicate film.

### Claim 9 (depends on 2)

The mask of claim 2, wherein the opening of the material layer defines a circuit feature of a circuit design layout.

### Claim 12 (depends on 1)

The mask of claim 1, wherein the material layer is patterned to further include an island that defines a circuit feature of a circuit design layout, wherein the island further includes a through-opening that has a sub-resolution dimension.

### Claim 13

A mask, comprising:
a transparent substrate having a first region and a second region being adjacent the first region;
a material layer substantially transparent and disposed over the transparent substrate and patterned to form a transparent feature within the first region and an opening within the second region; and
an etch stop layer interposed between the material layer and the transparent substrate, wherein the etch stop layer includes at least one of ruthenium oxide, tungsten nitride, and titanium nitride and is doped with at least one of phosphorous (P), calcium (Ca), and sodium (Na), and continuously extends from the first region to the second region.

### Claim 14 (depends on 13)

The mask of claim 13, wherein
one of the transparent feature and the opening defines a circuit feature to be imaged on a semiconductor substrate using a light radiation during a lithography process;
the transparent feature has a transmittance larger than 90% to the light radiation; and
the material layer has a thickness and composition to provide a phase difference of about 180° between a first beam of the light radiation transmitted through the mask within the first region and a second beam of the light radiation transmitted through the mask within the second region during a lithography process.

### Claim 15 (depends on 13)

The mask of claim 13, wherein the etch stop layer completely covers the first region and the second region,

### Claim 16 (depends on 13)

The mask of claim 13, wherein
the transparent substrate includes fused quartz; and
the material layer includes a material selected from the group consisting of silicon oxide doped with carbon, silicate glass dispersed with chromophore and sol-gel silicate.

### Claim 17 (depends on 13)

The mask of claim 13, wherein the material layer includes silicon (Si), oxygen (O), carbon (C), nitrogen (N), phosphorous (P), and boron (B).

### Claim 18 (depends on 13)

The mask of claim 13, wherein the material layer includes silicon at an atomic percentage between 30% and 60%, oxygen at an atomic percentage between 30% and 60%, and carbon at an atomic percentage below 10%, and wherein the etch stop layer includes tungsten nitride doped with sodium (Na).

### Claim 19 (depends on 13)

The mask of claim 13, wherein the etch stop layer includes at least one of titanium nitride doped with boron (B), and tungsten nitride doped with sodium (Na).

### Claim 20

A method for integrated circuit fabrication, comprising:
providing a semiconductor substrate;
providing a photoresist layer over the semiconductor substrate;
providing a mask that includes
a substrate;
an etch stop layer disposed on the substrate, wherein the etch stop layer includes at least one of ruthenium oxide, tungsten nitride, and titanium nitride and is doped with at least one of phosphorous (P), calcium (Ca), and sodium (Na); and
a material layer substantially transparent to a light radiation and disposed on the etch stop layer and patterned according to an integrated circuit pattern; and
forming the integrated circuit pattern on the semiconductor substrate by utilizing the mask in a lithography process including
performing a lithography exposure process to the semiconductor substrate utilizing the mask; and
developing the exposed photoresist layer.