# US 9,437,481 B2 · Self-aligned double patterning process for two dimensional patterns

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- Number: US 9,437,481 B2
- Document ID: US9437481B2
- Status: Granted
- Kind: B2
- Application number: 14/674,792
- Filed: 2015-03-31
- Published: 2016-06-09
- Granted: 2016-09-06
- Earliest claimed: 2014-12-05
- Assignees: Globalfoundries Inc.
- Applicants: GLOBALFOUNDRIES Inc.
- Inventors: Lei Yuan; Jia Zeng; Youngtag Woo; Jongwook Kye
- Web page: https://patentgrep.com/patent/US9437481B2

## CPC

- H10W 20/081: {by forming openings in the dielectric parts}
- H10P 50/73: {using masks for insulating materials}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/089: {using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning}
- H10P 50/71: {using masks for conductive or resistive materials}
- H10P 76/00: Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography
- H10P 76/40: of masks comprising inorganic materials
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

One method includes forming a mandrel element above a hard mask layer, forming first and second spacers on the mandrel element, removing the mandrel element, a first opening being defined between the first and second spacers and exposing a portion of the hard mask layer and having a longitudinal axis extending in a first direction, forming a block mask covering a middle portion of the first opening, the block mask having a longitudinal axis extending in a second direction different than the first direction, etching the hard mask layer in the presence of the block mask and the first and second spacers to define aligned first and second line segment openings in the hard mask layer extending in the first direction, etching recesses in a dielectric layer disposed beneath the hard mask layer based on the first and second line segment openings, and filling the recesses with a conductive material.

## Claims

### Claim 1

A method, comprising:
forming a patterning template including a plurality of lines above a hard mask layer, wherein a portion of said hard mask layer is exposed between adjacent lines;
forming a block mask covering a middle portion of said plurality of lines;
etching said hard mask layer in the presence of said block mask and said patterning template to define aligned first and second line segment openings in said hard mask layer;
removing said block mask and said patterning template;
forming a cut mask above said hard mask layer after removing said block mask and said patterning template, said cut mask being patterned to define an opening disposed between said first and second line segment openings and exposing said hard mask layer;
etching said hard mask layer in the presence of said cut mask to define a line opening in said hard mask layer between said first and second line segment openings;
etching recesses in a dielectric layer disposed beneath said hard mask layer based on said first and second line segment openings and said line opening; and
filling said recesses with a conductive material.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming said patterning template comprises:
forming a mandrel element above said hard mask layer;
forming spacers on sidewalls of said mandrel element; and
removing said mandrel element, said spacers defining said plurality of lines.

### Claim 3 (depends on 1)

The method of claim 1, wherein said line opening is perpendicular to said first and second line segment openings.

### Claim 4 (depends on 1)

The method of claim 1, wherein said patterning template exposes a plurality of portions of said hard mask layer between sets of adjacent lines and etching said hard mask layer comprises etching said hard mask layer in the presence of said block mask to define sets of aligned first and second line segment openings in said hard mask layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein said line opening is disposed between said first and second line segment openings in each set.

### Claim 6 (depends on 1)

The method of claim 1, wherein said block mask comprises a first photoresist mask.

### Claim 7 (depends on 6)

The method of claim 6, wherein said cut mask comprises a second photoresist mask.

### Claim 8 (depends on 1)

The method of claim 1, wherein said etching of said hard mask layer in the presence of said block mask occurs prior to said etching of said hard mask layer in the presence of said cut mask.

### Claim 9 (depends on 1)

The method of claim 1, wherein said first and second line segment openings have a first longitudinal axis in a first direction and said line opening has a second longitudinal direction substantially perpendicular to said first direction.

### Claim 10 (depends on 1)

The method of claim 1, wherein a tip-to-tip spacing of said first and second line segment openings is defined by a width of said block mask.

### Claim 11

A method, comprising:
forming a hard mask layer above a dielectric layer;
forming a mandrel element above said hard mask layer;
forming first and second spacers on sidewalls of said mandrel element;
removing said mandrel element, a first opening being defined between said first and second spacers, said first opening exposing a portion of said hard mask layer and having a first longitudinal axis extending in a first direction;
forming a block mask covering a middle portion of said first opening, said block mask having a second longitudinal axis extending in a second direction different than said first direction;
etching said hard mask layer in the presence of said block mask and said first and second spacers to define aligned first and second line segment openings in said hard mask layer extending in said first direction and exposing portions of said dielectric layer;
removing said block mask and said first and second spacers;
etching recesses in said exposed portions of said dielectric layer through said first and second line segment openings in said hard mask layer; and
filling said recesses with a conductive material.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
forming a cut mask above said hard mask layer after removing said block mask and said patterning template, said cut mask being patterned to define an opening having a longitudinal axis in said second direction, said opening being disposed between said first and second line segment openings and exposing said hard mask layer; and
etching said hard mask layer in the presence of said cut mask to define a line opening disposed between said first and second line segment openings prior to etching said recesses.

### Claim 13 (depends on 12)

The method of claim 12, wherein said block mask comprises a first photoresist mask and said cut mask comprises a second photoresist mask.

### Claim 14 (depends on 12)

The method of claim 12, wherein said etching of said hard mask layer in the presence of said block mask occurs prior to said etching of said hard mask layer in the presence of said cut mask.

### Claim 15 (depends on 12)

The method of claim 12, wherein said line opening is perpendicular to said first and second line segment openings.

### Claim 16 (depends on 11)

The method of claim 11, wherein a tip-to-tip spacing of said first and second line segment openings is defined by a width of said block mask.

### Claim 17 (depends on 11)

The method of claim 11, wherein said first opening comprises one of a plurality of openings in a patterning template exposing said hard mask layer, and etching said hard mask layer comprises etching said hard mask layer in the presence of said block mask to define sets of aligned first and second line segment openings in said hard mask layer.

### Claim 18 (depends on 17)

The method of claim 17, wherein said line opening is disposed between said first and second line segment openings in each set.

### Claim 19 (depends on 11)

The method of claim 11, wherein said mandrel element comprises a one dimensional pattern.

### Claim 20 (depends on 19)

The method of claim 19, wherein said block mask and said cut mask comprise one dimensional patterns.