# US 2010/0167182 A1 · Backside phase grating mask and method for manufacturing the same

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- Number: US 2010/0167182 A1
- Document ID: US20100167182A1
- Status: Published application
- Kind: A1
- Application number: 12/493,075
- Filed: 2009-06-26
- Published: 2010-07-01
- Earliest claimed: 2008-12-26
- Assignees: Hynix Semiconductor Inc.
- Inventors: Sung Hyun OH; Byung Ho Nam
- Web page: https://patentgrep.com/patent/US20100167182A1

## CPC

- G03F 7/70158: {Diffractive optical elements}
- G03F 1/50: Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
- 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)

## Abstract

A mask includes mask patterns formed over a frontside of a substrate and a phase grating formed over a backside of the substrate. The mask patterns correspond to a layout of diagonal patterns extending in a direction rotated toward a predetermined direction from an axis of a rectangular coordinate system. The phase grating extends in a direction parallel to the extending direction of the mask patterns. The phase grating includes first and second phase regions alternately arranged over the backside of the substrate with a phase difference of 180° therebetween. The first and second phase regions induce a phase interference that blocks a zero-order light of an exposure light incident to the substrate and allows a primary light to be incident to the mask patterns.

## Claims

### Claim 1

A mask, comprising:
a substrate;
mask patterns formed over a frontside of the substrate, the mask patterns corresponding to a layout of diagonal patterns extending in a direction rotated toward a predetermined direction from an axis of a rectangular coordinate system; and
a phase grating with a linear shape formed over a backside of the substrate, the phase grating extending in a direction parallel to the extending direction of the mask patterns.

### Claim 2 (depends on 1)

The mask of claim 1, wherein the diagonal patterns correspond to a layout of active regions in a 6F2 cell arrangement.

### Claim 3 (depends on 1)

The mask of claim 1, wherein the phase grating includes first and second phase regions alternately arranged over the backside of the substrate with a phase difference of 180° therebetween, wherein the first and second phase regions induce a phase interference that blocks a zero-order light of an exposure light incident to the substrate and allows a primary light to be incident to the mask patterns.

### Claim 4 (depends on 3)

The mask of claim 3, wherein the first phase region includes a trench having a depth providing the phase difference of 180° to a surface of the backside of the substrate, and the second phase region is a surface region of the backside of the substrate which is delimited by the trench.

### Claim 5 (depends on 3)

The mask of claim 3, wherein a grating pitch including widths of the first phase region and the second phase region is approximately two times a pattern pitch including a width of each mask pattern and a width of a spacing of adjacent mask patterns.

### Claim 6 (depends on 3)

The mask of claim 3, wherein the phase grating is arranged in a region broadened by 800 to 1000 μm relative to an outside of a region in which the mask patterns are arranged.

### Claim 7

A mask, comprising:
a substrate;
a first region having first mask patterns formed over a frontside of the substrate, the first mask patterns corresponding to a layout of diagonal patterns extending in a direction rotated toward a predetermined direction from an axis of a rectangular coordinate system;
a second region having second mask patterns extending in an axial direction of the rectangular coordinate system; and
a phase grating with a linear shape selectively formed over a backside region of the substrate, wherein the phase grating corresponds to the first region and extends in a direction parallel to the extending direction of the first mask patterns.

### Claim 8 (depends on 7)

The mask of claim 7, wherein the diagonal patterns correspond to a layout of active regions in a 6F2 cell arrangement.

### Claim 9 (depends on 8)

The mask of claim 8, wherein the phase grating includes first and second phase regions alternately arranged over the backside of the substrate with a phase difference of 180° therebetween, wherein the first and second phase regions induce a phase interference that blocks a zero-order light of an exposure light incident to the substrate and allows a primary light to be incident to the mask patterns.

### Claim 10 (depends on 9)

The mask of claim 9, wherein the first phase region includes a trench having a depth providing the phase difference of 180° to a surface of the backside of the substrate, and the second phase region is a surface region of the backside of the substrate which is delimited by the trench.

### Claim 11 (depends on 9)

The mask of claim 9, wherein a grating pitch including widths of the first phase region and the second phase region is approximately two times a pattern pitch including a width of each mask pattern and a width of a spacing of adjacent mask patterns.

### Claim 12 (depends on 9)

The mask of claim 9, wherein the phase grating is arranged in a region broadened by 800 to 1000 μm relative to an outside of a region in which the mask patterns are arranged.

### Claim 13

A method for manufacturing a mask, comprising:
forming mask patterns over a frontside of a substrate, the mask patterns corresponding to a layout of diagonal patterns extending in a direction rotated toward a predetermined direction from an axis of a rectangular coordinate system; and
forming a phase grating with a linear shape over a backside of the substrate, the phase grating extending in a direction parallel to the extending direction of the mask patterns.

### Claim 14 (depends on 13)

The method of claim 13, wherein the forming of the phase grating includes:
forming a photoresist pattern over the backside of the substrate; and
forming trenches having a depth providing a phase difference of 180° to a surface of the backside of the substrate by performing a selective etch on the backside of the substrate exposed by the photoresist pattern.

### Claim 15 (depends on 14)

The method of claim 14, wherein the trenches are formed to have a pitch that is approximately two times a pattern pitch including a width of each mask pattern and a width of a spacing of adjacent mask patterns.

### Claim 16 (depends on 13)

The method of claim 13, wherein the forming of the photoresist pattern includes:
forming an Anti Reflective Coating (ARC) over the backside of the substrate;
coating a photoresist layer over the ARC;
making a mother mask having a pattern layout of the phase grating; and
selectively exposing and developing some of the photoresist layer using the mother mask.

### Claim 17 (depends on 13)

The method of claim 13, wherein the diagonal patterns correspond to a layout of active regions in a 6F2 cell arrangement.