METHODS TO IMPROVE THE IN-FILM DEFECTIVITY OF PECVD AMORPHOUS CARBON FILMS
An article having a protective coating for use in semiconductor applications and methods for making the same are provided. In certain embodiments, a method of coating an aluminum surface of an article utilized in a semiconductor processing chamber is provided. The method comprises providing a processing chamber; placing the article into the processing chamber; flowing a first gas comprising a carbon source into the processing chamber; flowing a second gas comprising a nitrogen source into the processing chamber; forming a plasma in the chamber; and depositing a coating material on the aluminum surface. In certain embodiments, the coating material comprises an amorphous carbon nitrogen containing layer. In certain embodiments, the article comprises a showerhead configured to deliver a gas to the processing chamber.
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This application if a continuation of U.S. patent application Ser. No. 12/255,638 filed Oct. 21, 2008, and published Feb. 19, 2009, as United States Patent Publication 2009/0044753, which is a divisional application of U.S. patent application Ser. No. 11/689,278, filed Feb. 28, 2007, and patented Apr. 7, 2009, as U.S. Pat. No. 7,514,125, which claims benefit of U.S. provisional patent application Ser. No. 60/805,706 (APPM/011269L), filed Jun. 23, 2006, all of which are incorporated herein by reference.
BACKGROUND1. Field
Embodiments of the invention as recited by the claims generally relate to an article having a protective coating for use in a semiconductor processing chamber and a method of making the same.
2. Description of the Related Art
Integrated circuits have evolved into complex devices that can include millions of transistors, capacitors and resistors on a single chip. The evolution of chip designs continually requires faster circuitry and greater circuit density that demand increasingly precise fabrication techniques and processes. One fabrication process frequently used is plasma enhanced chemical vapor deposition (PECVD).
PECVD is generally employed to deposit a thin film on a substrate or a semiconductor wafer. PECVD is generally accomplished by introducing a precursor gas or gases into a vacuum chamber. The precursor gas is typically directed through a showerhead typically fabricated from aluminum situated near the top of the chamber. Plasma is formed in the vacuum chamber. The precursor gas reacts with the plasma to deposit a thin layer of material on the surface of the substrate that is positioned on a substrate support. Purge gas is routed through holes in the support to the edge of the substrate to prevent deposition at the substrate's edge that may cause the substrate to adhere to the support. Deposition by-products produced during the reaction are pumped from the chamber through an exhaust system.
One material frequently formed on substrates using a PECVD process is amorphous carbon. Amorphous carbon is used as a hard mask material in semiconductor application because of its chemical inertness, optical transparency, and good mechanical properties. Precursor gases that may be used to form amorphous carbon generally include a hydrocarbon, such as propylene and hydrogen.
The etch selectivity of amorphous carbon films has been correlated to film density. Ion bombardment densification of amorphous carbon films is one method of increasing the etch selectivity of an amorphous carbon film, however, ion-bombardment induced film densification invariably leads to a proportional increase in the compressive film stress, both on the showerhead of the PECVD chamber and the substrate. Highly compressive carbon residues on the showerhead poorly adhere to the showerhead surfaces, producing flakes and particles during prolonged durations of deposition. The stray carbon residue builds on the showerhead and may become a source of contamination in the chamber. Eventually, the stray carbon residue may clog the holes in the showerhead that facilitate passage of the precursor gas therethrough thus necessitating removal and cleaning of the showerhead or possibly replacement.
Therefore, there is a need for an apparatus or method that reduces formation of loose carbon deposits on aluminum surfaces in semiconductor processing chambers.
SUMMARYEmbodiments of the present invention as recited by the claims generally provide an apparatus and method that reduces formation of loose carbon deposits on aluminum surfaces and reduces in-film particle formation in semiconductor processing chambers.
An article having a protective coating for use in semiconductor applications and methods for making the same are provided. In certain embodiments, a method of coating an aluminum surface of an article utilized in a semiconductor processing chamber is provided. The method comprises providing a processing chamber, placing the article into the processing chamber, flowing a first gas comprising a carbon source into the processing chamber, flowing a second gas comprising a nitrogen source into the processing chamber, and depositing a coating material on the aluminum surface. In certain embodiments, the coating material comprises a nitrogen containing amorphous carbon layer. In certain embodiments, the coated article is a showerhead configured to deliver a gas to the processing chamber.
In certain embodiments, a method of reducing contaminants in a layer deposited in a semiconductor processing chamber containing an aluminum surface is provided. The method comprises providing a semiconductor processing chamber, placing a substrate into the processing chamber, flowing a first gas comprising a carbon source into the processing chamber, flowing a second gas comprising a hydrogen source into the processing chamber, forming a plasma from an inert gas in the chamber, and depositing a layer on the substrate.
In certain embodiments, an article for use in a semiconductor processing chamber is provided. The article comprises a showerhead, a support pedestal, or a vacuum chamber body having an aluminum surface and a coating material comprising a nitrogen containing amorphous carbon material applied on the aluminum surface in a plasma enhanced chemical vapor deposition process.
In certain embodiments a showerhead having an aluminum surface coated with a nitrogen containing amorphous carbon material is provided. The nitrogen containing amorphous carbon material is applied to the showerhead by a method comprising flowing a first gas comprising a carbon source into the processing chamber, flowing a second gas comprising a nitrogen source into the processing chamber, forming a plasma in the chamber, and depositing the nitrogen containing amorphous carbon material on the aluminum surface.
In certain embodiments, a showerhead configured to deliver gas to a semiconductor processing chamber is provided. The showerhead comprises an upper surface, a lower surface comprising aluminum, wherein the lower surface has a surface roughness of between about 30 nm and about 50 nm, and a plurality of openings formed between the upper surface and the lower surface.
A more particular description of the invention, briefly summarized above, may be had by reference to certain embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain embodiments and are therefore not to be considered limiting of its scope.
To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures. It is contemplated that elements and/or process steps of one or more embodiments may be beneficially incorporated in one or more other embodiments without additional recitation.
DETAILED DESCRIPTIONIn certain embodiments, a processing system having coated aluminum surfaces that are advantageous for the deposition of amorphous carbon and other films is disclosed.
Plasma enhanced chemical vapor deposition (PECVD) techniques generally promote excitation and/or disassociation of the reactant gases by the application of an electric field to a reaction zone near the substrate surface, creating a plasma of reactive species immediately above the substrate surface. The reactivity of the species in the plasma reduces the energy required for a chemical reaction to take place, in effect lowering the required temperature for such PECVD processes.
In operation, the substrate 120 can be secured to the substrate pedestal 115 by providing a vacuum therebetween. The temperature of the substrate is elevated to a pre-determined process temperature by regulating thermal transfer to the substrate pedestal 115 by, for example, a heating element (not shown). During the deposition process, the substrate is heated to a steady temperature typically between about 200° C. and 700° C.
Gaseous components, which in certain embodiments may include propylene and hydrogen, can be supplied to the process chamber assembly 100 via the gas nozzle openings 142 in showerhead 110. A plasma is formed in the process chamber assembly 100 by applying RF power to a gas source such as argon or nitrogen. The gaseous mixture reacts to form a layer of amorphous carbon, for example Advanced Patterning Film or “APF” available from Applied Materials, Inc. of Santa Clara, Calif., on the surface of the substrate 120.
In certain embodiments, the coating material 210 comprises a layer of nitrogen containing amorphous carbon or other material that inhibits flaking of carbon residue from the showerhead 110. The thickness of the coating material 210 is sufficient to provide a “sticky” seasoned layer and is typically between about 500 Å and about 3000 Å, such as between about 1000 Å and about 2000 Å, for example about 1500 Å. The coating material 210 functions as an adhesion promoting layer between the bare lower surface 205 of the showerhead 110 and the carbon residues deposited on the showerhead 110 during the amorphous carbon deposition. Thus the coating material 210 adheres to aluminum surfaces as well as amorphous carbon surfaces. Since nitrogen can bond with carbon as well as aluminum surfaces, it can create a “sticky” seasoned layer. In certain embodiments, the seasoned layer can be predominantly carbon which can allow forthcoming amorphous carbon residues to adhere to the showerhead and thereby can inhibit flaking or fall-on particles.
Typical carbon sources include hydrocarbon compounds with the general formula CxHy where x has a range of between 2 and 10 and y has a range of between 2 and 22. For example, propylene (C3H6), propyne (C3H4), propane (C3H8), butane (C4H10), butylene (C4H8), butadiene (C4H6), acetelyne (C2H2), pentane, pentene, pentadiene, cyclopentane, cyclopentadiene, benzene, toluene, alpha terpinene, phenol, cymene, norbornadiene, as well as combinations thereof, may be used as the hydrocarbon compound. Liquid precursors may be used to deposit amorphous carbon films. The use of liquid precursors in the deposition of amorphous carbon films is further discussed in United States Patent Application Publication No. 2005/0287771, published Dec. 29, 2005, entitled LIQUID PRECURSORS FOR THE CVD DEPOSITION OF AMORPHOUS CARBON FILMS, which is herein incorporated by reference to the extent it does not conflict with the current specification. These liquid precursors include, but are not limited to, toluene, alpha terpinene (A-TRP), and norbornadiene (BCHD).
Similarly, a variety of gases such as hydrogen (H2), nitrogen (N2), ammonia (NH3), or combinations thereof, among others, can be added to the gas mixture, if desired. Argon (Ar), helium (He), and nitrogen (N2) can be used to control the density and deposition rate of the amorphous carbon layer.
The carbon source compound may be introduced into the chamber at a flow rate of between about 200 sccm and about 2000 sccm, such as between about 1,500 sccm and about 2,000 sccm, for example, 700 sccm. The nitrogen source may be introduced into the chamber at a flow rate of between about 100 sccm and about 15,000 sccm, such as between about 5,000 sccm and about 10,000 sccm, for example, 8,000 sccm. Optionally, a carrier gas can be introduced into the chamber at a flow rate of between about 0 sccm and about 20,000 sccm. The carrier gas may be nitrogen gas or an inert gas. In certain embodiments, the flow rates are chosen such that the coating material is predominately carbon. For example, the carbon source compound may be introduced into the chamber at a first flow rate, and the nitrogen source compound may be introduced into the chamber at a second flow rate such that the ratio of the second flow rate to the first flow rate is between about 50:1 and about 1:1, such as between about 10:1 and about 1:1, for example, about 7:1. In certain embodiments, the carbon source compound is propylene and the nitrogen source is nitrogen.
In certain embodiments, during deposition of the nitrogen containing amorphous carbon layer, the substrate can be typically maintained at a temperature between about 200° C. and about 700° C., preferably between about 250° C. and about 350° C., such as about 300° C. In certain embodiments, a RF power level of between about 20 W and about 1,600 W, for example, about 1,000 W, for a 300 mm substrate is typically used in the chamber. The RF power can be provided at a frequency between about 0.01 MHz and 300 MHz, for example, 13.56 MHz. In certain embodiments, the RF power can be provided to a gas distribution assembly or “showerhead” electrode in the chamber. In certain embodiments, the RE power may be applied to a substrate support in the chamber. In certain embodiments, the RF power may be provided at a mixed frequency, such as at a high frequency of about 13.56 MHz and a low frequency of about 350 kHz. The RF power may be cycled or pulsed and continuous or discontinuous.
In certain embodiments, the spacing between the showerhead and support pedestal during the deposition of the nitrogen containing amorphous carbon layer may be between about 280 mils and about 1,500 mils, for example, 400 mils, and the pressure in the chamber may be between about 1 Torr and about 10 Torr, for example, 7 Torr.
Still referring to
In certain embodiments a method for improving the adhesion strength of the lower surface 205 of the showerhead 110 is provided.
In certain embodiments,
In certain embodiments, a method of reducing the presence of in-film adders is provided. The method comprises the addition of H2 as a dilution gas during the bulk deposition process. In certain embodiments, this method may be used with deposition processes described in United States Patent Application Publication No. 2005/0287771, published Dec. 29, 2005, entitled LIQUID PRECURSORS FOR THE CVD DEPOSITION OF AMORPHOUS CARBON FILMS and U.S. patent application Ser. No. 11/427,324, filed Jun. 28, 2006, entitled METHOD FOR DEPOSITING AN AMORPHOUS CARBON FILM WITH IMPROVED DENSITY AND STEP COVERAGE which are herein incorporated by reference to the extent they do not conflict with the current specification. In certain embodiments, the addition of H2 has been shown to significantly reduce the in-film particles. It is believed that several mechanisms play a role in this phenomenon. For example, hydrogen species can passivate the gas phase CHx species, thereby limiting the growth of these radicals into potential particle nuclei. Additionally, for example, the addition of H2 may lead to a widening of the plasma sheath at the electrode surfaces, thus leading to a reduction in the momentum of the ions bombarding the electrodes.
In certain embodiments,
While the foregoing is directed to certain embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims
1. An article for use in a semiconductor processing chamber, the article comprising:
- a showerhead, a support assembly, or a vacuum chamber body having an aluminum surface; and
- a coating material comprising a nitrogen containing amorphous carbon layer applied on the aluminum surface in a plasma enhanced chemical vapor deposition process.
2. The article of claim 1, wherein the nitrogen containing amorphous carbon layer has a thickness between about 500 Å and about 3000 Å.
3. The article of claim 1, wherein the coating has a thickness between about 500 Å and about 3000 Å.
4. The article of claim 1, wherein the coating promotes adhesion of carbon to the article.
5. The article of claim 1, wherein the coating has a thickness between about 500 Å and about 3000 Å, and a surface roughness between about 30 nm and about 50 nm.
6. The article of claim 1, wherein the nitrogen containing amorphous carbon layer is formed by placing the article in a processing chamber, providing a gas mixture comprising a carbon source and a nitrogen source to the chamber, and forming a plasma in the chamber.
7. The article of claim 6, wherein the gas mixture further comprises an inert gas.
8. The article of claim 6, wherein the carbon source is a hydrocarbon.
9. The article of claim 6, wherein the carbon source has a general formula CxHy, where x is between 2 and 10, and y is between 2 and 22.
10. The article of claim 6, wherein the carbon source is selected from the group consisting of propylene, propyne, propane, butane, butylene, butadiene, acetylene, pentane, pentene, pentadiene, cyclopentane, cyclopentadiene, benzene, toluene, alpha terpinene, phenol, cymene, norbornadiene, and combinations thereof.
11. The article of claim 6, wherein the carbon source is propylene and the nitrogen source is nitrogen gas.
12. A semiconductor processing chamber, comprising:
- a chamber body;
- a showerhead; and
- a substrate support assembly, wherein at least one of the chamber body, the showerhead, and the substrate support assembly has an aluminum surface and a coating comprising a nitrogen containing amorphous carbon layer applied to the aluminum surface in a plasma enhanced chemical vapor deposition process.
13. The semiconductor processing chamber of claim 12, wherein the coating has a thickness between about 500 Å and about 3000 Å, and a surface roughness between about 30 nm and about 50 nm.
Type: Application
Filed: Apr 26, 2012
Publication Date: Aug 16, 2012
Applicant: APPLIED MATERIALS, INC. (Santa Clara, CA)
Inventors: Deenesh Padhi (Sunnyvale, CA), Chiu Chan (Foster City, CA), Sudha Rathi (San Jose, CA), Ganesh Balasubramanian (Sunnyvale, CA), Jianhua Zhou (San Jose, CA), Karthik Janakiraman (San Jose, CA), Martin J. Seamons (San Jose, CA), Visweswaren Sivaramakrishnan (Santa Clara, CA), Derek R. Witty (Fremont, CA), Hichem M'Saad (Santa Clara, CA)
Application Number: 13/456,447
International Classification: C23C 16/50 (20060101);