Patent Application
20250191893
The background description provided here is for the purpose of generally presenting the context of the disclosure. Information described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The disclosure relates to parts for use in a plasma processing chamber. More specifically, the disclosure relates to dielectric, plasma exposed parts in a plasma processing chamber.
In forming semiconductor devices, plasma processing chambers are used to process the substrates. Some plasma processing chambers have dielectric parts, such as liners, gas distribution plates, and edge rings.
For some of the dielectric parts for plasma processing chambers, silicon carbide (SIC) has been widely used due to the high etch resistance of SiC. The technique to produce a SiC edge ring is predominantly through a chemical vapor deposition (CVD) method where a thick SiC coating is grown onto a graphite mandrel. After the removal of the graphite mandrel, the CVD-produced SiC blank is then machined into an edge ring. With more aggressive plasma chemistries and more stringent demand in a part lifetime, CVD-produced pure SiC cannot meet lifetime requirements.
It has been found that for cryogenic plasma processing, such as cryogenic etching, the life of a component, such as an edge ring, would be four to five times lower than the lifetime of the component in noncryogenic plasma processing.
To achieve the foregoing and in accordance with the purpose of the present disclosure, an apparatus for plasma processing a wafer at cryogenic temperatures is provided. A wafer support is adapted to support a wafer within a plasma processing chamber. A gas source provides gas to the plasma processing chamber. A cooling system provides cooling the wafer support. A component comprises a spark plasma sintered body comprising a sintering powder comprising at least one of a doped silicon carbide powder, wherein a dopant is at least one of aluminum (Al), yttrium (Y), tungsten (W), tantalum (Ta), tungsten carbide (WC), tantalum carbide (TaC), and aluminum-silicon carbide (AlSiC), or a doped carbide, wherein the carbide is at least one of boron carbide (B4C), WC, or TaC and wherein a dopant is at least one of B, W, molybdenum (Mo), Al, and Ta, or pure B4C, WC, TaC, W, or Mo.
In another manifestation, a component for use in a cryogenic plasma processing system is provided comprising a spark plasma sintered body comprising a sintering powder comprising at least one of a doped silicon carbide powder, wherein a dopant is at least one of aluminum (Al), yttrium (Y), tungsten (W), tantalum (Ta), tungsten carbide (WC), tantalum carbide (TaC), and aluminum-silicon carbide (AlSiC), or a doped carbide, wherein the carbide is at least one of boron carbide (B4C), WC, or TaC and wherein a dopant is at least one of B, W, molybdenum (Mo), Al, and Ta, or pure B4C, WC, TaC, W, or Mo.
These and other features of the present disclosure will be described in more detail below in the detailed description and in conjunction with the following figures.
The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
The present disclosure will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one 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 structures have not been described in detail in order to not unnecessarily obscure the present disclosure.
In plasma processing, various components of a plasma processing chamber may be eroded. The eroded component causes changes in the process, which may affect wafer to wafer uniformity. In addition, an eroded component may need to be replaced increasing down time of the plasma process, decreasing throughput, and increasing cost of ownership. Cryogenic plasma processing is plasma processing at a temperature of less than −20° C. It has been found that cryogenic plasma processing, such as cryogenic etching may cause components to erode four to five times faster than the components would for non-cryogenic plasma processing. In some applications, it has been found that plasma processing at cryogenic temperatures provides improved processes. Increased erosion from using such cryogenic temperature plasma processing would increase downtime, increase cost of ownership, degrade system performance, and lower throughput.
To facilitate understanding,
Referring back to
As compared to conventional sintering processes, the SPS process (also referred to as pulsed electric current sintering (PECS), Field-Assisted Sintering (FAST) or Plasma Pressure Compaction (P2C)) involves contemporaneous use of pressure and high-intensity, low-voltage (e.g., 5-12 V), pulsed current to dramatically reduce processing/heating times (e.g., 5-10 minutes (min) instead of several hours) and yield high-density components. In one embodiment, a pulsed DC current is transmitted to the deposited the sintering powder 204a using conductive pads 212 as electrodes, while pressure (e.g., between 10 megapascals (MPa) up to 500 MPa or more) is simultaneously axially applied to the sintering powder 204a via reciprocation of the conductive pads 212 under mono-axial mechanical force. A “mono-axial force” is herein defined to mean a force applied along a single axis or direction creating mono-axial compression. The mold 208 and sintering powder 204a are generally placed under vacuum during at least a portion of the process. Pulsed-current patterns (ON: OFF), typically in milliseconds, enable high heating rates (up to 1000° C./min or more), and rapid cooling/quenching rates of (up to 200° C./min or more) for heating the sintering powder 204a to temperatures ranging from under 1000° C. to 2500° C. In one embodiment, the ON-OFF DC pulse-energizing of the SPS process generates one or more of the following in the Sintering powder: 1) spark plasma, 2) spark impact pressure, 3) Joule heating, and 4) an electrical field diffusion effect.
It is appreciated that the scale and geometry of the mold 208, conductive pads 212, sintering powder 204a, and SPS-formed edge ring 204b provided in the schematic views of
In one embodiment of an SPS process, provided for exemplary purposes only, sintering of the sintering powder is conducted under vacuum (6<P(Pa)<14) while being simultaneously subjected to a pulsed current. The SPS thermal treatment may be implemented as follows: 1) a degassing treatment performed for a period between 3 minutes to 10 minutes, and preferably with the sintering powder 204a subjected to 3 minutes under limited applied load (e.g. between 10 megapascals (MPa) and 20 MPa) and 2 minutes under increasing load up to 40 MPa to 100 MPa, and 2) heating up to between 1850° C. and 1950° C. at 100° C. min−1 under an applied load between 40 MPa to 100 MPa and a soaking time of 5 minutes at maximum temperature then cooling down to room temperature. It is appreciated that one or more of the SPS process parameters, including sintering powder constituent ratios and particulate size, pressures, temperatures, treatment periods, and current pulse sequences, may be varied as appropriate to optimize the SPS process.
Referring to the side view of
Following the SPS process, the component may be further processed (step 112, e.g., polishing, machining, or like process) to specifically adapt the component for use in a plasma processing chamber. It is appreciated that the mold and/or SPS process may be structured so that the further processing in step 112 is not required. The SPS-formed edge ring 204b may be formed as a near net shape part (NNS). A NNS part requires subsequent machining removing less than 20% of the volume of the NNS part.
Referring to the side view of
The processed SPS body is then mounted or otherwise installed in a cryogenic plasma processing chamber (step 116), wherein the SPS component is used in the cryogenic plasma processing chamber (step 120) for performing cryogenic plasma processing of one or more wafers or substrates. During cryogenic plasma processing, one or more surfaces of the SPS component is exposed to plasma and/or dielectric-etch processes.
The cryogenic plasma processing performed by the cryogenic plasma processing chamber may include one or more processes of etching, depositing, passivating, or another plasma process. The cryogenic plasma processing may also be performed in combination with non-plasma processing and non-cryogenic processes. Such processes may expose the various components of the plasma processing chamber to plasmas containing halogen and/or oxygen that result in erosion or degradation of the part. In an embodiment, the SPS component is exposed to a cryogenic etch process.
The SPS process illustrated in
Accordingly,
Referring to the cross-section view of
Referring to the respective plan and side views of
Referring to the respective plan and side views of
The plasma processing components (e.g., edge ring 204c, gas distribution plate 304c) generated from the SPS process are resistant to erosion from exposure to plasma, such that the component is either no longer a consumable, or substantially inhibits consumption to limit or obviate the need to change or replace the component due to erosion. Being more etch resistant, components fabricated and installed via the process illustrated in
The SPS-formed components provide an advantage of better manufacturability and lower cost over conventional edge ring manufacturing processes where material is built up layer by layer in a CVD process.
Referring to the schematic system view of
In one exemplary configuration, the one or more processed and SPS-formed components comprise consumable plasma processing chamber components such as an edge ring, gas distribution plate, high flow liner, etc. In some embodiments, the cryogenic plasma processing system 400 comprises a gas distribution plate 406, also referred to as a “showerhead” for providing a gas inlet within a plasma processing chamber 404. The gas distribution plate 406 may be mounted in a plasma processing chamber 404 along with an electrostatic chuck (ESC) 416, all being enclosed by a chamber wall 450. Within the plasma processing chamber 404, a substrate or wafer 407 is positioned on top of the ESC 416 that acts as a wafer support to support the substrate 407. The ESC 416 may provide a bias from an ESC power source 448. A gas source 410 is connected to the plasma processing chamber 404 through the gas distribution plate 406. An ESC temperature controller 451 is connected to the ESC 416 and provides temperature control of the ESC 416. In this embodiment, the ESC temperature controller may be part of a cooling system that is able to cool the ESC 416 to cryogenic temperatures of less than-20° C. or −60° C. A radio frequency (RF) power source 430 provides RF power to the ESC 416 and an upper electrode. In this embodiment, the upper electrode is the gas distribution plate 406. In a preferred embodiment, 13.56 megahertz (MHz), 2 MHz, 60 MHz, and/or optionally, 27 MHz power sources make up the RF power source 430 and the ESC power source 448. A controller 435 is controllably connected to the RF power source 430, the ESC power source 448, an exhaust pump 420, and the gas source 410.
A high flow liner 460 is a liner within the plasma processing chamber 404, and may also be formed, installed, and used in accordance with the steps illustrated in
An edge ring 464 surrounds the substrate 407. The plasma processing chamber 404 uses the edge ring 464 to plasma process the substrate 407. It is desirable that the top surface of the edge ring 464 be level with a top surface of the substrate 407. Therefore, the use of an SPS-formed edge ring 204c as edge ring 464 obviates various mechanisms that are typically provided to move the edge ring as the edge ring is consumed in order to keep the top surface of the edge ring even with the top surface of the substrate. In addition, once an edge ring is sufficiently consumed, the edge ring must be replaced, causing downtime for the plasma processing chamber. In other embodiments, such components may be placed in locations shielded from plasma. Ceramic edge rings have a low coefficient of thermal expansion and good electrical and thermal conductivity. In addition, the component is a dielectric component with an etch resistivity of greater than 25 ohms centimeter (ohms-cm).
In other embodiments, the components may be parts of other types of plasma processing chambers such as a TCP (transformer coupled plasma) reactor, a bevel plasma processing chambers or like device. Examples of components of plasma processing chambers that may be provided in various embodiments are confinement rings, plasma exclusion rings, edge rings, the electrostatic chuck, ground rings, chamber liners, door liners, the pinnacle, a showerhead, a dielectric power window, gas injectors, edge rings, ceramic transfer arms, or other components. In some embodiments, the cryogenic temperature is a temperature of less than −60° C. In some embodiments, a cryogenic etch may be used to etch stacks of alternating layers of silicon oxide and polysilicon (OPOP) or stacks of alternating layers of silicon oxide and silicon nitride (ONON). The component may be made of sintered powders of materials that are used as hardmasks in such processes, since some hardmasks are of a plasma resistant dielectric material that provides a volatile etch product.
In various embodiments, the sintering powder consists essentially of SiC doped with Al. SiC and Al are not exotic materials. High purity SiC and Al may be obtained at a low expense. In addition, Al dopant may be evenly dispersed in the SiC grain. In various embodiments, when the component body is eroded, the sintering powder forms volatile etch products.
In various embodiments, the sintering powder consists essentially of B4C. Sintering powder that consists essentially of B4C is able to be easily densely sintered.
In various embodiments, the sintering powder consists essentially of W or Mo. In other embodiments, the sintering powder consists essentially of WC doped with at least one of B, W, Mo, Al, Ta, and B4C.
In various embodiments, the sintering powder consists essentially of SiC doped with Y. SiC and Y are not exotic materials. High purity SiC and Y may be obtained at a low expense. In embodiments where the component is made of sintered pure WC, a high density component would be easy to form by sintering.
While this disclosure has been described in terms of several preferred embodiments, there are alterations, modifications, permutations, and various substitute equivalents, which fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present disclosure. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and various substitute equivalents as fall within the true spirit and scope of the present disclosure.
This application claims the benefit of priority of U.S. Application No. 63/322,982, filed Mar. 23, 2022, which is incorporated herein by reference for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/015810 | 3/21/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63322982 | Mar 2022 | US |
