# US 9,437,415 B2 · Layer alignment in FinFET fabrication

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,437,415 B2
- Document ID: US9437415B2
- Status: Granted
- Kind: B2
- Application number: 13/912,936
- Filed: 2013-06-07
- Published: 2013-10-17
- Granted: 2016-09-06
- Earliest claimed: 2011-08-25
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Ming-Feng Shieh; Kuei-Liang Lu
- Web page: https://patentgrep.com/patent/US9437415B2

## CPC

- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- H10D 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 86/011: {comprising FinFETs}
- H10P 50/695: {characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask}
- H10W 46/00: Marks applied to devices, e.g. for alignment or identification
- H10W 46/301: {for alignment}
- H10W 46/501: {for use before dicing}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Methods for aligning layers more accurately for FinFETs fabrication. An embodiment method includes forming a first pattern in a workpiece using a first photomask, forming a second pattern in the workpiece using a second photomask, the second photomask aligned to the first pattern, and aligning a third pattern to the first and the second patterns by aligning a first feature of the third pattern to a first feature of the first pattern in a first direction, and aligning a second feature of the third pattern to a first feature of the second pattern in a second direction orthogonal to the first direction.

## Claims

### Claim 1

A method, comprising:
forming a first feature in a workpiece with a first patterning process;
after forming the first feature, forming a second feature in the workpiece with a second patterning process;
aligning a third photomask in a first direction and a second direction, the aligning in the first direction being performed by aligning one or more features of the third photomask to the first feature formed with the first patterning process and no features formed by the second patterning process, and the aligning in the second direction being performed by aligning one or more features of the third photomask to the second feature formed with the second patterning process and no features formed by the first patterning process, the second direction is different than the first direction; and
forming a third pattern using the third photomask;
wherein a second pattern is formed using a second photomask, wherein the second photomask is aligned to a first pattern formed using a first photomask, and wherein the first pattern comprises a sidewall of a fin.

### Claim 2 (depends on 1)

The method of claim 1, wherein the third pattern defines a FEOL layer, the FEOL layer being a shield layer or a polysilicon layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first pattern defines a plurality of spacer elements abutting a plurality of dummy line features.

### Claim 4 (depends on 1)

The method of claim 1, wherein the third pattern is formed by a photolithography process.

### Claim 5 (depends on 1)

The method of claim 1, further comprising trimming away end portions of spacer elements in the third pattern.

### Claim 6 (depends on 1)

The method of claim 1, wherein the third pattern defines a plurality of fins.

### Claim 7 (depends on 1)

The method of claim 1, wherein the first direction is orthogonal to the second direction.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first pattern and the second pattern are formed by a photolithography process.

### Claim 9 (depends on 1)

The method of claim 1, wherein the second pattern defines an active area.

### Claim 10 (depends on 1)

The method of claim 1, wherein the second pattern defines an alignment mark.

### Claim 11 (depends on 1)

The method of claim 1, wherein the third pattern includes a grid of fins.

### Claim 12 (depends on 1)

The method of claim 1, wherein the second pattern comprises an end of a fin.

### Claim 13 (depends on 1)

The method of claim 1, wherein the first pattern defines a plurality of spacer elements abutting a plurality of dummy line features, wherein the second pattern defines an active area.

### Claim 14 (depends on 13)

The method of claim 13, wherein at least one of the second photomask and the third photomask is one of an attenuating phase shift mask, an alternating phase shift mask, and a chromeless phase shift mask.

### Claim 15

A method, comprising:
forming a first feature in a workpiece with a first patterning process;
after forming the first feature, forming a second feature in the workpiece with a second patterning process;
aligning a third photomask in a first direction and a second direction, the aligning in the first direction being performed by aligning one or more features of the third photomask to the first feature formed with the first patterning process and no features formed by the second patterning process, and the aligning in the second direction being performed by aligning one or more features of the third photomask to the second feature formed with the second patterning process and no features formed by the first patterning process, the second direction is different than the first direction; and
forming a third pattern using the third photomask;
wherein the second pattern is formed using a second photomask, wherein the second photomask is aligned to the first pattern, and wherein the second pattern comprises an end of a fin.

### Claim 16 (depends on 15)

The method of claim 15, wherein the second pattern defines an alignment mark.

### Claim 17 (depends on 15)

The method of claim 15, wherein the third pattern defines a FEOL layer, the FEOL layer being a shield layer or a polysilicon layer.

### Claim 18 (depends on 15)

The method of claim 15, wherein the third pattern includes spacer elements having end portions removed.

### Claim 19 (depends on 15)

The method of claim 15, wherein the first pattern defines a plurality of spacer elements abutting a plurality of dummy line features, wherein the second pattern defines an active area.

### Claim 20 (depends on 15)

The method of claim 15, wherein the third pattern includes a grid of fins.