# US 10,121,661 B2 · Self aligned pattern formation post spacer etchback in tight pitch configurations

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- Number: US 10,121,661 B2
- Document ID: US10121661B2
- Status: Granted
- Kind: B2
- Application number: 15/786,090
- Filed: 2017-10-17
- Published: 2018-07-12
- Granted: 2018-11-06
- Earliest claimed: 2017-01-11
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Sean D. Burns; Lawrence A. Clevenger; Matthew E. Colburn; Nelson M. Felix; Sivananda K. Kanakasabapathy; Christopher J. Penny; Roger A. Quon; Nicole A. Saulnier
- Web page: https://patentgrep.com/patent/US10121661B2

## CPC

- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 50/71: {using masks for conductive or resistive materials}
- H10P 50/73: {using masks for insulating materials}
- H10W 20/063: {by forming conductive members before forming protective insulating material}
- H10W 20/0633: {using subtractive patterning of the conductive members}
- H10W 20/089: {using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning}
- H10W 20/43: Layouts of interconnections
- H10D 64/01326: {Aspects related to lithography, isolation or planarisation of the conductor}
- H10K 71/233: {by photolithographic etching}
- H10N 70/063: {by etching of pre-deposited switching material layers, e.g. lithography}
- H10P 14/60: of insulating materials
- H10P 76/2041: {Photolithographic processes}
- H10W 20/069: {by forming self-aligned vias or self-aligned contact plugs}
- H10W 72/01255: {by using masks}
- H10W 72/01951: {Changing the shapes of bond pads}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A method of forming a structure for etch masking that includes forming first dielectric spacers on sidewalls of a plurality of mandrel structures and forming non-mandrel structures in space between adjacent first dielectric spacers. Second dielectric spacers are formed on sidewalls of an etch mask having a window that exposes a connecting portion of a centralized first dielectric spacer. The connecting portion of the centralized first dielectric spacer is removed. The mandrel structures and non-mandrel structures are removed selectively to the first dielectric spacers to provide an etch mask. The connecting portion removed from the centralized first dielectric spacer provides an opening connecting a first trench corresponding to the mandrel structures and a second trench corresponding to the non-mandrel structures.

## Claims

### Claim 1

An etch method comprising:
forming first dielectric spacers on sidewalls of a plurality of mandrel structures that are present on a substrate;
forming second dielectric spacers on sidewalls of an etch mask having a window that exposes a connecting portion of a centralized first dielectric spacer in the etch window, wherein the second dielectric spacers cover said first dielectric spacers that do not include the connecting portion;
removing the connecting portion of the centralized first dielectric spacer; and
etching the substrate using the first dielectric spacers as an etch mask, wherein an opening is formed from the space provided by said removing the connecting portion of the centralized first dielectric spacer that connects a first trench proximate to the mandrel structure and a second trench proximate to a non-mandrel structure.

### Claim 2 (depends on 1)

The etch method of claim 1, wherein the substrate is a silicon containing dielectric layer.

### Claim 3 (depends on 2)

The etch method of claim 2, wherein the opening in the substrate is filled to provide a metal line.

### Claim 4 (depends on 1)

The etch method of claim 1, wherein forming the first dielectric spacers on sidewalls of the mandrel structures comprises:
conformally depositing a material layer for the dielectric spacers on the plurality of mandrel structures; and
etching the material layer, wherein the horizontally orientated portions are removed, and the vertically orientated portions of the material layer remains to provide the first dielectric spacers.

### Claim 5 (depends on 1)

The etch method of claim 1, wherein forming said etch mask comprises:
depositing a photoresist layer; and
patterning the photoresist layer to provide said etch window.

### Claim 6 (depends on 5)

The etch method of claim 5, wherein the etch window exposes the connecting portion of the centralized first dielectric spacer.

### Claim 7 (depends on 1)

The etch method of claim 1, wherein said removing the connecting portion of the centralized first dielectric spacer comprises an etch that is selective to the second dielectric spacers.

### Claim 8 (depends on 1)

The etch method of claim 1, further comprising removing the mandrel structures and non-mandrel structures selectively to the first dielectric spacers.

### Claim 9 (depends on 1)

The etch method of claim 1, wherein the mandrel structures, the non-mandrel structure and the first dielectric spacers have geometries that are arranged to provide a self-aligned double patterning (SADP) etch process.

### Claim 10

A method of forming a structure for etch masking comprising:
forming first dielectric spacers on sidewalls of a plurality of mandrel structures;
forming second dielectric spacers on sidewalls of an etch mask having a window that exposes a connecting portion of a centralized first dielectric spacer in the etch window, wherein the second dielectric spacers have a height greater than said first dielectric spacers;
removing the connecting portion of the centralized first dielectric spacer; and
removing the mandrel structures and a non-mandrel material, wherein remaining portions of the first dielectric spacers provide an etch mask, and the connecting portion removed from the centralized first dielectric spacer provides an opening connecting a first trench proximate to the mandrel structures and a second trench proximate to the non-mandrel structures.

### Claim 11 (depends on 10)

The method of claim 10, wherein forming the first dielectric spacers on sidewalls of the mandrel structures comprises conformally depositing a material layer for the dielectric spacers on the plurality of mandrel structures.

### Claim 12 (depends on 11)

The method of claim 11, wherein forming the dielectric spacers further comprises etching the material layer, wherein the horizontally orientated portions are removed, and the vertically orientated portions of the material layer remains to provide the first dielectric spacers.

### Claim 13 (depends on 10)

The method of claim 10, wherein forming said etch mask comprises depositing a photoresist layer; and patterning the photoresist layer to provide said etch window.

### Claim 14 (depends on 13)

The method of claim 13, wherein the etch window exposes the connecting portion of the centralized first dielectric spacer.

### Claim 15 (depends on 10)

The method of claim 10, wherein said removing the connecting portion of the centralized first dielectric spacer comprises an etch that is selective to the second dielectric spacers.

### Claim 16 (depends on 10)

The method of claim 10, wherein said removing the mandrel structures and non-mandrel structures comprises an etch that is selective to the first dielectric spacers.

### Claim 17 (depends on 10)

The method of claim 10, wherein the mandrel structures, the non-mandrel structure and the first dielectric spacers have geometries that are arranged to provide a self-aligned double patterning (SADP) etch process.