# US 8,465,991 B2 · Carbon containing low-k dielectric constant recovery using UV treatment

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- Number: US 8,465,991 B2
- Document ID: US8465991B2
- Status: Granted
- Kind: B2
- Application number: 12/973,549
- Filed: 2010-12-20
- Published: 2011-05-19
- Granted: 2013-06-18
- Earliest claimed: 2006-10-30
- Assignees: Novellus Systems, Inc.
- Applicants: Bhadri N. Varadarajan; Kevin M. McLaughlin; Bart van Schravendijk
- Inventors: Bhadri N. Varadarajan; Kevin M. McLaughlin; Bart van Schravendijk
- Web page: https://patentgrep.com/patent/US8465991B2

## CPC

- H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
- H10P 72/0436: {mainly by radiation}
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 20/088: {involving partial etching of via holes}
- H10W 20/095: {by irradiating with electromagnetic or particle radiation (plasma treatment H10W20/096)}
- 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

## Abstract

A method for the ultraviolet (UV) treatment of carbon-containing low-k dielectric and associated apparatus enables process induced damage repair. The methods of the invention are particularly applicable in the context of damascene processing to recover lost low-k property of a dielectric damaged during processing, either pre-metallization, post-planarization, or both. UV treatments can include an exposure of the subject low-k dielectric to a constrained UV spectral profile and/or chemical silylating agent, or both.

## Claims

### Claim 1

A method of forming a semiconductor device, comprising:
receiving in a processing chamber a semiconductor device substrate comprising a carbon-containing low-k dielectric having a first dielectric constant;
exposing the carbon containing low-k dielectric to a UV treatment, the treatment comprising at least one of:
(a) exposure to UV radiation having a spectral profile characterized by greater than 50% of the UV radiation power having a wavelength of greater than 300 nm; and
(b) exposure to UV radiation and a chemical silylating agent;
such that the dielectric constant of the carbon-containing low-k dielectric is decreased to a second dielectric constant;
wherein the treatment comprises exposure to the chemical silylating agent prior to the UV radiation exposure; and
wherein a second UV radiation exposure precedes the exposing the carbon containing low-k dielectric to the chemical silylating agent.

### Claim 2 (depends on 1)

The method of claim 1, wherein there is no air-break between exposures.

### Claim 3 (depends on 1)

The method of claim 1, wherein there is an air-break between one or more exposures.

### Claim 4 (depends on 1)

The method of claim 1, wherein a thermal anneal exposure precedes the exposing the carbon containing low-k dielectric to the chemical silylating agent.

### Claim 5 (depends on 1)

The method of claim 1, wherein the dielectric is selected from the group consisting of carbon doped oxides formed from octamethyl cyclotetrasiloxane (OMCTS), tetramethylcyclotetrasiloxane (TMCTS), dimethyldimethoxysilane (DMDMOS), and diethoxymethylsilane (DEMS).

### Claim 6 (depends on 5)

The method of claim 5, wherein the alkyl silane is selected from the group consisting of dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, bis(dimethylamino)dimethylsilane, dimethylaminao trimethyl silane, bis(diethylamino)dimethylsilane, ethylmethyldichlorosilane and diethyldichlorosilane, diethyldiethoxysilane.

### Claim 7 (depends on 6)

The method of claim 6, wherein the silylating agent is bis(dimethylamino)dimethylsilane.

### Claim 8 (depends on 6)

The method of claim 6, wherein the silylating agent is dimethyldichlorosilane.

### Claim 9 (depends on 1)

The method of claim 1, wherein greater than 50% of the (a) and/or (b) UV radiation power is in a wavelength range of about 300 to 450 nm.

### Claim 10 (depends on 1)

The method of claim 1, wherein greater than 50% of the (a) and/or (b) UV radiation power is in a wavelength range of about 300 to 400 nm.

### Claim 11 (depends on 1)

The method of claim 1, wherein less than 10% of the (a) and/or (b) UV radiation power is in a wavelength range below 300 nm.

### Claim 12 (depends on 1)

The method of claim 1, wherein less than 5% of the (a) and/or (b) UV radiation power is in a wavelength range below 300 nm.

### Claim 13 (depends on 1)

The method of claim 1, wherein less than 1% of the (a) and/or (b) UV radiation power is in a wavelength range below 300 nm.

### Claim 14 (depends on 1)

The method of claim 1, wherein the proportion of (a) and/or (b) UV radiation power in a wavelength range of 200 to 240 nm to UV radiation power in a wavelength range of 300 to 400 nm in the UV radiation to which the carbon containing low-k dielectric is exposed is no more than 10%.

### Claim 15 (depends on 1)

The method of claim 1, wherein a Fe-filled (“D”) bulb is used a source for the (a) and/or (b) UV radiation.

### Claim 16 (depends on 15)

The method of claim 15, wherein a high pass filter is used with the D bulb to filter out the UV radiation having a wavelength below 300 nm prior to exposure of the carbon containing low-k dielectric.

### Claim 17 (depends on 16)

The method of claim 16, wherein the filter is a 295 nm high pass filter.

### Claim 18 (depends on 1)

The method of claim 1, wherein a Ga-filled (“V”) bulb is used a source for the (a) and/or (b) UV radiation.

### Claim 19 (depends on 18)

The method of claim 18, wherein a high pass filter is used with the V bulb to filter out the UV radiation having a wavelength below 300 nm prior to exposure of the carbon containing low-k dielectric.

### Claim 20 (depends on 19)

The method of claim 19, wherein the filter is a 295 nm high pass filter.