Yttria coating for plasma processing chamber components

Abstract

Constituent parts of a plasma processing chamber are provided. The yttria coating is formed on the surface of the part body. The yttria coating is deposited by aerosol deposition and annealed. The yttria coating is at least 95% by weight pure yttria.

Description

Cross - reference to related applications

[0001] This application claims the benefit of priority of U.S. Application No. 63 / 346,043, filed May 26, 2022, which is incorporated by reference herein for all purposes.

Background Art

[0002] The present disclosure relates generally to the manufacture of semiconductor devices. The present disclosure relates in particular to plasma chamber components used in the manufacture of semiconductor devices.

[0003] During the processing of semiconductor wafers, a plasma processing chamber is used to process semiconductor devices. The plasma processing chamber is exposed to plasma, and the components within the plasma processing chamber can deteriorate. Components of the plasma processing chamber that deteriorate due to plasma can become sources of contamination. Ceramic alumina (aluminum oxide (Al2O3)) is a common material used for components of plasma processing chambers because alumina has some resistance to plasma etching. However, alumina does not have sufficient plasma etching resistance.

[0004] The background art described herein is intended to generally present the content of the present disclosure. The inventions of the presently named inventors are not to be regarded as prior art to the present disclosure, either expressly or implicitly, to the extent that they are described in a manner that does not fall within the scope of the prior art at the time of filing of this background art section and the description of the prior art at the time of filing of this application.

Summary of the Invention

[0005] In order to achieve the above in accordance with the objectives of the present disclosure, components of a plasma processing chamber are provided. A yttria coating is formed on the surface of the component body. The yttria coating is deposited by aerosol deposition and annealed. The yttria coating is at least 95 wt% pure yttria.

[0006] In another embodiment, the component body is configured for use in a plasma processing chamber. An aerosol deposition coating of yttria powder is deposited on the component body. The aerosol deposition coating is at least 95 wt% yttria. The aerosol deposition coating is annealed.

[0007] These and other features of the present disclosure will be described in more detail in the following detailed description of the invention, taken in conjunction with the following drawings.

Brief Description of the Drawings

[0008] The present disclosure is described by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals mean like elements.

[0009]

Figure 1

[0010]

Figure 2A

Figure 2B

Figure 2C

[0011]

Figure 3

Detailed Description of the Invention

[0012] Here, the present disclosure is described with reference to several preferred embodiments thereof, as shown in the accompanying drawings. In the following description, several specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and / or configurations have not been described in detail so as not to obscure the present disclosure unnecessarily.

[0013] Aerosol deposition (AD) coating technology is still a method often deployed to form a "plasma-resistant or etch-resistant" film on chamber components. However, as manufacturing manufacturers transition to further technology nodes and apply stricter standards to particles than ever before, particle generation persists as a primary failure mode for these types of barrier films. Smooth-shaped AD-coated parts tend to have weak regions found at the terminal regions that are the ends of the film. Depending on the part, texturing is required. Since the film has a low density, texturing often has a high tendency to generate particles (texturing is difficult to achieve on a fully densified film).

[0014] According to some embodiments described herein, components of a plasma processing chamber are provided with a film having higher etch resistance. The film is deposited using yttrium oxide (Y2O3) (also known as yttria) powder.

[0015] Figure 1 is a high-level flowchart of a process used in an embodiment for ease of understanding. A component body is provided (step 104). Figure 2A is a schematic cross-sectional view of the component body 204 used in the embodiment. In some embodiments, the component body 204 includes a ceramic material. In some embodiments, the component body 204 is made of ceramic alumina. In some embodiments, the ceramic alumina component body 204 is a dielectric power window. In some embodiments, a borehole 206 passes through the center of the power window to provide a gas injector.

[0016] Yttria powder is provided (step 108). In this example, the yttria powder has a purity of at least 95 wt%. In some embodiments, the average particle size of the yttria powder ranges from 40 nm to 50 nm.

[0017] The aerosol deposition film of yttrium oxide powder is then deposited on the surface of the component body 204 (step 112). Aerosol deposition is achieved by passing a carrier gas through a fluidized bed of solid yttria powder. The yttria powder particles are accelerated through the nozzle by a pressure difference and form an aerosol jet at the outlet of the nozzle. The aerosol is then directed towards the surface of the component body 204, and the aerosol jet impinges on the surface at high speed. The powder mixture particles are split into nano-sized solid pieces to form a film. Optimization of the carrier gas species, gas consumption, stand-off distance, and scanning speed provides a high-quality film. As described above, aerosol deposition can be carried out at room temperature. FIG. 2B is a schematic cross-sectional view of the component body 204 after the aerosol deposition of the AD film 208 of yttria powder has been deposited.

[0018] After the AD film 208 has been deposited (step 112), a film conditioning process may be provided to the AD film 208 as needed (step 114). For example, in some embodiments, the AD film 208 may be cleaned and polished. In some embodiments, the cleaning may include a 3000 grit polish scrub of the entire window to remove polishing slurry and loose abrasive grains or debris. A scrub may then be applied following a blast of solid CO2 to remove remaining loose features and / or scrub residues. This may then be followed by a precision wet clean using deionized water. The window may then be baked.

[0019] Next, the AD coating 208 is annealed (step 116). In this embodiment, the AD coating is heated to a temperature in the range of 650°C to 890°C. In some embodiments, the AD coating is heated to a temperature in the range of 700°C to 850°C. The annealing temperature is maintained below 900°C to prevent a portion of the yttria from combining with aluminum oxide to form a yttrium aluminum oxide compound. The formation of the yttrium aluminum oxide compound would increase the porosity and result in a decrease in corrosion resistance in the terminal region. By maintaining the annealing temperature below 900°C, at least 95 wt% of the coating remains pure yttria. In some embodiments, the annealing process provides a maximum temperature for a period of 4 to 12 hours. Also, to prevent the component body 204 from cracking, the temperature is raised and lowered at a rate of 30°C or less per hour. In some embodiments, the annealing is performed in an atmosphere where oxygen can be present. FIG. 2C is a cross-sectional view of the AD coating after the AD coating has been annealed to form the annealed coating 212. Particle size measurements using a transmission electron microscope revealed that the annealing process increased the average particle size from a range of 40 nm to 50 nm to a range of 70 nm to 100 nm. In some embodiments, the annealing increases the particle size by a factor of 1.5 to 2.5. In some embodiments, a transmission electron microscope backscattering (TEM-EBS) process may be used to measure the average particle size. Also, X-ray diffraction is a method for determining the average particle size of single crystal nanoparticles or crystallites in a nanocrystalline bulk material. Scherrer's equation relates the size of the crystallites in a solid to the broadening of the peaks in the diffraction pattern. Scherrer's equation is D hkl = Kλ / (B hkl cosθ) (where D hkl = the crystallite size in the direction perpendicular to the lattice plane, hkl = the Miller indices of the plane being analyzed, K is a numerical factor often meaning the crystallite shape factor, λ is the wavelength of the X-ray, B hkl is the width (full width at half maximum) of the X-ray diffraction peak in radians, and θ is the Bragg angle).

[0020] In some embodiments, the anneal coating 212 is at least 95 (weight)% pure yttria, has a porosity of less than 1 volume%, and has an average thickness of 5 μm to 20 μm. In some embodiments, the anneal coating 212 is at least 99 weight% pure yttria.

[0021] After the AD coating 208 has been annealed (step 116), adjustment of the anneal coating 212 may be provided as needed (step 114). For example, the anneal coating 212 may be scrubbed, then blasted, and finally washed. In some embodiments, the blasting of the anneal coating 212 may be performed by blasting the anneal coating 212 with cryogenic carbon dioxide. When the annealing process causes particle growth, the annealing may cause some particles to protrude such that the particles are weakly connected or other particles are pushed out and peeled off as the surrounding particles grow. The washing process may be used to remove free particles on the anneal coating 212 that may occur in the annealing process to reduce contaminants. Some embodiments may use a washing process similar to the washing process provided after the AD coating is applied.

[0022] Post-annealing of the component having the AD coating 208 provides the possibility to "tune" the internal particle structure and porosity to achieve the morphology / characteristics of a particular material. Post-annealing provides a way to adjust the particle size in the AD yttria coating 208 by promoting particle growth. As a result of particle growth, together with the additional effect of particle fusion (reduction of internal particle porosity), the coating density is improved. At the surface level, grain coarsening (affected by annealing) can change the surface roughness and porosity. Furthermore, annealing reduces the internal stress of the AD yttria coating 208, thereby reducing crack / delamination events.

[0023] The annealing process can increase density, reduce porosity, and increase particle size, and the overall effect can lead to a low rate at which the film can be etched by hydrochloric acid (HCl). In some embodiments, the AD film 208 after annealing with 5 wt% HCl coarsens from a roughness of about 10 nm - 20 nm to a roughness of 60 nm - 100 nm in about 3 minutes. In some embodiments, the annealed film 212 with 5 wt% HCl remains at a roughness of 10 nm - 20 nm after up to 30 minutes of exposure to HCl. The HCl test shows that annealing makes the film more corrosion resistant.

[0024] The component body 204 is attached to the plasma processing chamber (step 120). In the example of the figure, the component body 204 is attached to the plasma processing chamber as a dielectric induction power window. The plasma processing chamber is used to process the substrate (step 124). Plasma is generated in the chamber to process the substrate, such as etching the substrate, and the annealed film 212 is exposed to the plasma. The annealed film 212 provides high etching resistance to protect the component body 204.

[0025] FIG. 3 schematically shows an example of a plasma processing chamber system 300 that can be used in an embodiment. The plasma processing chamber system 300 includes a plasma reactor 302 having a plasma processing confinement chamber 304 therein. A plasma power supply 306 is adjusted by a matching network 308 and supplies power to a transformer coupled plasma (TCP) coil 310 located near a dielectric induction power window 312 to generate a plasma 314 in the plasma processing confinement chamber 304 by providing inductively coupled power. A pinnacle 372 (pinnacle is a registered trademark) extends from a chamber wall 376 of the plasma processing confinement chamber 304 to the dielectric induction power window 312 to form a pinnacle ring. The pinnacle 372 is inclined with respect to the chamber wall 376 and the dielectric induction power window 312 such that an inner angle between the pinnacle 372 and the chamber wall 376 and an inner angle between the pinnacle 372 and the dielectric induction power window 312 are each greater than 90° and less than 180°. The pinnacle 372 provides an inclined ring near the top of the plasma processing confinement chamber 304 as shown in the figure. The TCP coil (upper power supply) 310 may be configured to form a uniform diffusion profile inside the plasma processing confinement chamber 304. For example, the TCP coil 310 may be configured to generate a donut-shaped power distribution within the plasma 314. The dielectric induction power window 312 is provided to separate the plasma processing confinement chamber 304 from the TCP coil 310 while allowing energy to pass from the TCP coil 310 to the plasma processing confinement chamber 304. A wafer bias voltage power supply 316 adjusted by a matching network 318 provides power to an electrode 320 to set a bias voltage on a substrate 366. The substrate 366 is supported by the electrode 320. A controller 324 controls the plasma power supply 306 and the wafer bias voltage power supply 316.

[0026] The plasma power supply 306 and the wafer bias voltage power supply 316 may be configured to operate at a specific radio frequency (e.g., 13.56 megahertz (MHz), 27 MHz, 2 MHz, 60 MHz, 400 kilohertz (kHz), 2.54 gigahertz (GHz), or a combination thereof). The plasma power supply 306 and the wafer bias voltage power supply 316 may be appropriately sized to supply a range of power to achieve the desired process performance. For example, in one embodiment, the plasma power supply 306 may supply power in the range of 50 to 5000 watts, and the wafer bias voltage power supply 316 may supply a bias voltage in the range of 20 to 2000 volts (V). Also, the TCP coil 310 and / or the electrode 320 may be composed of two or more sub-coils or sub-electrodes. The sub-coils or sub-electrodes may be powered by a single power supply or multiple power supplies.

[0027] As shown in FIG. 3, the plasma processing chamber system 300 further includes a gas source / gas supply mechanism 330. The gas source 330 is in fluid connection with the plasma processing confinement chamber 304 through a gas inlet such as a gas injector 340. The gas injector 340 may be installed at any convenient position within the plasma processing confinement chamber 304 and may take any form for injecting gas. However, it is preferred that the gas inlet can be configured to form an "adjustable" gas injection shape. The adjustable gas injection shape enables independent adjustment of the respective gas flows to multiple regions of the plasma processing confinement chamber 304. The gas injector is more preferably attached to the dielectric induction power window 312. The gas injector may be attached above or inside the power window or may form part of the power window. Process gas and by-products are removed from the plasma processing confinement chamber 304 by a pressure control valve 342 and a pump 344. The pressure control valve 342 and the pump 344 also function to maintain a specific pressure within the plasma processing confinement chamber 304. The pressure control valve 342 can maintain a pressure of less than 1 torr during processing. The edge ring 360 is installed around the substrate 366. The gas source / gas supply mechanism 330 is controlled by a controller 324. Kiyo by Lam Research Corporation of Fremont, California may be used to implement the embodiments.

[0028] In various embodiments, the component may be other components of the plasma processing chamber (e.g., confinement rings, edge rings, Corvus rings, electrostatic chucks (ESCs), ground rings, chamber liners, door liners, inner electrodes / shower heads, outer electrodes, other components through which high-frequency (RF) energy can pass, crosses, sleeves, pins, nozzles, injectors, forks, arms, etc.). Other components of other types of plasma processing chambers may be used. For example, in an embodiment, the plasma exhaust ring of a bevel etching chamber may be coated. In another example, the plasma processing chamber may be a dielectric processing chamber or a conductor processing chamber. In some embodiments, the component body 204 is formed of a ceramic material. In other embodiments, the component body 204 is formed of a silicon (Si) material. In some embodiments, one or more surfaces, but not all, are coated.

[0029] In some embodiments, the component is the inductive power window 312 with a gas injector 340 passing through the borehole 206. In such embodiments, the annealed coating 212 has a termination region 220 at the outer end of the inductive power window 312 shown in FIG. 3 and a termination region 224 shown in FIG. 2C at the inner end of the borehole 206 used to provide the gas injector 340 shown in FIG. 3. The non-annealed coating will have a higher porosity in the termination region than other parts of the coating. The higher porosity causes more corrosion and more contaminants due to corrosion. Since the gas injector 340 is above the center of the wafer, the termination region near the gas injector will generate more contaminant particles near the center of the wafer. Such an increase in contaminant particles was seen near the center of the wafer. Annealing of the coating reduces corrosion and contaminant particles near the center of the wafer. Some embodiments improve the corrosion resistance at the termination points where the coating is prone to corrosion. Some embodiments provide more uniform corrosion resistance throughout the coating including the termination region. Annealing results in grain growth, reducing the voids that cause pitting by suppressing pitting through crystal growth. In some embodiments, the coating in the termination region has a density of at least 95% by volume. In some embodiments, the coating in the termination region has a density of at least 99% by volume. In some embodiments, the coating in the termination region has a porosity of less than 1% by volume. The above HCl test helps to show such a low porosity.

[0030] This disclosure has been described in terms of some preferred embodiments, but there are changes, substitutions, modifications, and various alternative equivalents that fall within the scope of this disclosure. Note also that there are many other ways to implement the methods and apparatuses of this disclosure. Therefore, the appended claims are intended to be construed to include all such changes, substitutions, and various alternative equivalents that fall within the true spirit and scope of this disclosure.

Claims

1. A component of a plasma processing chamber, comprising: a component body; and a yttria coating on the surface of the component body, which is deposited by aerosol deposition and annealed, and at least 95% by weight of which is pure yttria. The component comprising the above.

2. The component according to Claim 1, wherein the yttria coating has an average yttria particle size in the range of 70 to 100 nm.

3. The component according to Claim 1, wherein the yttria coating is annealed at a maximum temperature in the range of 650 °C to 900 °C.

4. The component according to Claim 1, wherein the component body is formed of a ceramic material.

5. The component according to Claim 1, wherein the component body forms a power window.

6. The component according to Claim 1, wherein the yttria coating has a porosity of less than 1% by volume.

7. The component according to Claim 1, wherein the component body forms at least one power window.

8. The component according to Claim 1, wherein the yttria coating in the terminal region has a porosity of less than 1% by volume.

9. A method, comprising: providing a component body configured to be used in a plasma processing chamber; depositing an aerosol deposition coating of yttria powder on the component body, wherein at least 95% by weight of the aerosol deposition coating is yttria; and annealing the aerosol deposition coating. The method comprising the above.

10. The method according to Claim 9, wherein annealing the aerosol deposition coating comprises annealing the yttria coating at a maximum temperature in the range of 650 °C to 900 °C.

11. The method according to Claim 9, wherein the aerosol deposition coating has an average yttria particle size in the range of 70 to 100 nm.

12. The method according to Claim 9, wherein providing the component body comprises forming a ceramic component body.

13. The method according to Claim 9, wherein providing the component body comprises forming a power window.

14. The method according to Claim 9, wherein annealing the aerosol deposition coating is provided in the presence of oxygen.

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