# US 8,772,159 B2 · Method of fabricating electrical contact

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- Number: US 8,772,159 B2
- Document ID: US8772159B2
- Status: Granted
- Kind: B2
- Application number: 13/364,289
- Filed: 2012-02-01
- Published: 2013-08-01
- Granted: 2014-07-08
- Earliest claimed: 2012-02-01
- Assignees: United Microelectronics Corp.
- Applicants: I-Ming Tseng; Tsung-Lung Tsai; Yi-Wei Chen
- Inventors: I-Ming Tseng; Tsung-Lung Tsai; Yi-Wei Chen
- Web page: https://patentgrep.com/patent/US8772159B2

## CPC

- H10W 70/66: Conductive materials thereof
- H10D 64/0112: {using conductive layers comprising silicides}
- H10D 64/01125: {the silicides being formed by chemical reaction with the semiconductor after the contact hole formation}
- H10D 84/017: {Manufacturing their source or drain regions, e.g. silicided source or drain regions}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10W 20/033: {in openings in dielectrics}
- H10W 20/047: {by introducing additional elements therein}
- H10W 20/40: Interconnections external to wafers or substrates, e.g. back-end-of-line [BEOL] metallisations or vias connecting to gate electrodes
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method of fabricating an electrical contact comprises the following steps. A substrate having at least a silicon region is provided. At least an insulation layer is formed on the substrate, wherein the insulation layer comprises at least a contact hole which exposes the silicon region. A metal layer is formed on sidewalls and bottom of the contact hole. An annealing process is performed to form a first metal silicide layer in the silicon region nearby the bottom of the contact hole. A conductive layer covering the metal layer and filling up the contact hole is then formed, wherein the first metal silicide layer is transformed into a second metal silicide layer when the conductive layer is formed.

## Claims

### Claim 1

A method of fabricating an electrical contact, comprising:
providing a substrate having at least a silicon region;
forming at least an insulation layer on the substrate, wherein the insulation layer comprises at least a contact hole exposing the silicon region and having sidewalls and a bottom surface;
forming a metal layer on the sidewalls and the bottom of the contact hole;
performing an annealing process to form a first metal silicide layer in the silicon region nearby the bottom of the contact hole; and
forming a conductive layer covering the metal layer and filling up the contact hole, wherein the first metal silicide layer is transformed into a second metal silicide layer when forming the conductive layer, wherein a temperature of the annealing process is lower than a temperature applied in a step for forming the conductive layer.

### Claim 2 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein a thickness of the metal layer adjacent to the bottom face is reduced simultaneously when performing the annealing process.

### Claim 3 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the metal layer adjacent to the bottom surface disappears simultaneously when performing the annealing process.

### Claim 4 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the temperature of the annealing process is lower than 350° C.

### Claim 5 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the second metal silicide layer and the metal layer have same metal components.

### Claim 6 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the first metal silicide layer has larger resistivity than the second metal silicide layer.

### Claim 7 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the contact hole is a slot contact hole.

### Claim 8 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the annealing process is a rapid thermal annealing process.

### Claim 9 (depends on 1)

The method of fabricating the electrical contact according to claim 1, after forming the metal layer and before performing the annealing process, further comprising:
forming a barrier layer on the metal layer.

### Claim 10 (depends on 1)

The method of fabricating the electrical contact according to claim 1, wherein the silicon region comprises monocrystalline silicon or polysilicon and comprises phosphor, arsenic, boron, germanium or a combination thereof.