# US 10,121,880 B2 · Fin field-effect transistor and fabrication method thereof

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- Number: US 10,121,880 B2
- Document ID: US10121880B2
- Status: Granted
- Kind: B2
- Application number: 15/398,786
- Filed: 2017-01-05
- Published: 2017-07-13
- Granted: 2018-11-06
- Earliest claimed: 2016-01-07
- Assignees: Semiconductor Manufacturing International (Shanghai) Corporation; Semiconductor Manufacturing International (Beijing) Corporation
- Applicants: Semiconductor Manufacturing International (Shanghai) Corporation; Semiconductor Manufacturing International (Beijing) Corporation
- Inventors: Gang Mao
- Web page: https://patentgrep.com/patent/US10121880B2

## CPC

- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10D 62/115: {Dielectric isolations, e.g. air gaps}
- H10D 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/8311: {the IGFETs characterised by having different channel structures}
- H10D 84/834: {comprising FinFETs}
- H10P 50/283: {by chemical means}
- H10P 50/73: {using masks for insulating materials}
- H10P 95/062: {involving a dielectric removal step}
- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H10D 84/83138: {the IGFETs characterised by having different shapes or dimensions of their gate conductors}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure provides fin field-effect transistors and fabrication methods thereof. An exemplary fabrication process includes providing a substrate having a first region and a second region; forming first fins in the first region and second fins in the second region; forming a liner oxide layer on side surfaces of the first fins, the second fins and a surface of the substrate; forming an insulating barrier layer on the liner oxide layer in the first region; forming a precursor material layer on the insulating barrier layer in the first region and on the liner oxide layer in the second region; performing a curing annealing process to convert the precursor material into an insulation layer; and removing a top portion of the insulation layer to form an isolating layer and removing portions of the liner oxide layer, the insulating barrier layer, the first oxide layer and the second oxide layer.

## Claims

### Claim 1

A method for fabricating a fin field-effect transistor (FinFET), comprising:
providing a substrate having a first region, a second region, and a plurality of first fins on the first region of the substrate and a plurality of second fins on the second region of the substrate;
forming a liner oxide layer on side surfaces of the first fins, side surfaces of the second fins and a surface of the substrate;
forming an insulating barrier layer on a portion of the liner oxide layer on the first region of the substrate;
forming a precursor material layer on the insulating barrier layer on the first region of the substrate and on the liner oxide layer on the second region of the substrate;
performing a curing annealing process to convert the precursor material layer into an insulation layer, a first oxide layer being formed on the side surfaces of the first fins, and a second oxide layer being formed on the side surfaces of the second fins, wherein a thickness of the first oxide layer is smaller than a thickness of the second oxide layer after the curing annealing process; and
removing a top portion of the insulation layer to form an isolation layer and removing portions of the liner oxide layer, the insulating barrier layer, the first oxide layer and the second oxide layer higher than a surface of the isolation layer, wherein a half width at half maximum feature size of portions of the first fins higher than the surface of the isolation layer is greater than a half width at half maximum feature size of portions of the second fins higher than the surface of the isolation layer after removing portions of the liner oxide layer, the insulation layer, the first oxide layer and the second oxide layer, that are higher than the surface of the isolation layer.

### Claim 2 (depends on 1)

The method according to claim 1, wherein:
a half width at half maximum feature size of the first fins is identical to a half width at half maximum feature size of the second fins before forming the liner oxide layer.

### Claim 3 (depends on 1)

The method according to claim 1, wherein forming the insulating barrier layer comprises:
forming an insulating barrier film on the liner oxide layer;
forming a patterned layer on the liner oxide layer on the first region of the substrate; and
removing a portion of the insulating barrier film on the second region of the substrate by etching the insulating barrier film using the patterned layer as an etching mask.

### Claim 4 (depends on 1)

The method according to claim 1, wherein:
a thickness difference between the first oxide layer and the second oxide layer is in a range of approximately 3 nm-5 nm; and
a feature size difference in half width at half maximum between portions of the first fins higher than the isolation layer and portions of the second fins higher than the isolation layer is in a range of approximately 3 nm-5 nm.

### Claim 5 (depends on 1)

The method according to claim 1, wherein:
the precursor material layer is flowable; and
the precursor material layer is formed by a flowable chemical vapor deposition process.

### Claim 6 (depends on 5)

The method according to claim 5, wherein:
precursors of the flowable chemical vapor deposition process include one or more of saline, disaline, methylsaline, dimethyl saline, trimethylsaline, tetramethylsaline, tetraethyl orthosilicate, (3-Aminopropyl) triethoxysilane, octamethyl cyclotetrasiloxane, 1,1,3,3-tetramethyldisiloxane, tetramethylcyclotetrasiloxane, trisilylamine, and disilylamine.

### Claim 7 (depends on 1)

The method according to claim 1, wherein:
the curing annealing process is performed in a H2O-containing environment.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the H2O-containing environment further comprises:
one or more gases of O2 and O3.

### Claim 9 (depends on 1)

The method according to claim 1, wherein:
a temperature of the curing annealing process is in a range of approximately 400° C.-500° C.

### Claim 10 (depends on 1)

The method according to claim 1, after the curing annealing process, further comprising:
performing a second annealing process to the insulation layer,
wherein:
a temperature of the second annealing process is in a range of approximately 900° C.-1100° C.; and
the second annealing process is performed in a N2 environment.

### Claim 11 (depends on 1)

The method according to claim 1, wherein:
the top portion of the insulation layer is removed by a wet etching process to form the isolation layer.

### Claim 12 (depends on 1)

The method according to claim 1, wherein:
the liner oxide layer is formed by an in situ steam generation oxidation process.

### Claim 13 (depends on 1)

The method according to claim 1, before forming the liner oxide layer, further comprising:
forming a hard mask layer on top surfaces of the first fins and top surfaces of the second fins,
wherein:
the insulating barrier layer covers the hard mask layer on the first region of the substrate; and
a top of the insulating barrier layer is higher than a top of the hard mask layer.

### Claim 14 (depends on 13)

The method according to claim 13, before removing the top portion of the insulation layer, further comprising:
polishing the insulation layer until a top surface of the hard mask layer is exposed.

### Claim 15 (depends on 14)

The method according to claim 14, further comprising:
removing the hard mask layer.

### Claim 16 (depends on 1)

The method according to claim 1, wherein:
the insulating barrier layer is made of one of silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, silicon oxycarbonitride, and boron nitride.

### Claim 17 (depends on 1)

The method according to claim 1, wherein:
a thickness of the insulating barrier layer is in a range of approximately 30 Å-50 Å.

### Claim 18 (depends on 1)

The method according to claim 1, wherein:
the liner oxide layer is made of silicon oxide.