Transformer coupling plasma window for semiconductor etching equipment and preparation method of transformer coupling plasma window

Abstract

The invention discloses a transformer coupling plasma window for semiconductor etching equipment and a preparation method thereof, the upper surface of a base body of the transformer coupling plasma window is a flat and straight surface, the upper surface is provided with a circular mounting step, the mounting step and an air inlet through hole are concentrically arranged, the diameter of the mounting step is larger than that of the air inlet through hole, and the diameter of the mounting step is larger than that of the air inlet through hole. The lower surface of the base body is an annular curved surface, and a spherical microstructure is formed on the lower surface through chemical etching. The structure of the lower surface of the transformer coupling plasma window is optimized, the annular curved surface structure is adopted, the spherical microstructure is formed on the lower surface through chemical etching, and the annular curved surface structure and the spherical microstructure act synergistically, so that the plasma adsorption uniformity is remarkably improved, the reset time is greatly shortened, and the equipment maintenance cost is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor etching equipment, and in particular to a transformer-coupled plasma window for semiconductor etching equipment and a preparation method thereof. Background Art

[0002] ICP (Inductively Coupled Plasma) etching is a major category of etching technology. It uses an RF power supply to excite gas to generate plasma. Under vacuum and low-pressure conditions, the RF generated by the ICP RF power supply is output to a ring-shaped coupling coil. The gases mixed in a certain proportion are coupled through glow discharge to generate high-density plasma. These plasmas bombard the surface of the silicon wafer, breaking the chemical bonds of the silicon wafer material. The by-products react with the etching gas to separate from the silicon wafer in the form of gas and are extracted away, thereby achieving the etching effect.

[0003] ICP etching equipment boasts advantages such as high precision and high speed, and is widely used in the etching of materials such as silicon, silicon nitride, oxides, and metals. The TCP (Transformer Coupled Plasma) window is a key component of the equipment, receiving the plasma etching gas in the etching equipment while maintaining the cleanliness of the etching chamber by adsorbing and depositing complex byproduct particles such as silicon oxide and metal oxide during the etching process. In the actual silicon wafer processing process, to ensure process stability, various key components within the ICP equipment, including the TCP window, need to be regularly replaced. After replacing the components, the equipment is pre-run, and silicon wafer production begins once the various parameters set within the etching chamber meet the specifications.

[0004] The traditional TCP window is designed with a standardized flat surface (both the upper and lower surfaces are flat) with a central hole. The flat surface with a certain degree of roughness is assembled facing the electrostatic chuck and receives the plasma etching during the etching process. The traditional TCP window has the following defects in the actual production process:

[0005] 1. The side of the traditional TCP window facing the electrostatic chuck (the lower surface) adopts a flat surface design, and the surface treatment mostly relies on physical grinding, which makes it difficult to form a uniform microstructure, affecting the uniformity of plasma distribution. The plasma adsorption capacity is insufficient, resulting in uneven deposition of byproduct particles and a high risk of contamination of the etching chamber.

[0006] 2. The traditional TCP window adopts a flat surface design on the side facing the electrostatic chuck, which limits the etching parameter setting range of the etching equipment. The time from component replacement to equipment operation stabilization (i.e., recovery time) is long, and the equipment maintenance cost is high. Summary of the Invention

[0007] In order to solve the above technical problems, the present application provides a transformer-coupled plasma window for semiconductor etching equipment and a preparation method thereof, so as to solve the problems of uneven plasma adsorption, long recovery time and high maintenance cost caused by the flat design of the lower surface of the traditional TCP window.

[0008] The first object of the present application is to provide a transformer-coupled plasma window for semiconductor etching equipment.

[0009] The above-mentioned application objective 1 of this application is achieved through the following technical solutions:

[0010] A transformer-coupled plasma window for semiconductor etching equipment includes a disc-shaped transformer-coupled plasma window substrate. The transformer-coupled plasma window substrate includes an upper surface and a lower surface opposite to the upper surface. The lower surface is the side facing the electrostatic chuck in the etching chamber when installed. The center of the transformer-coupled plasma window substrate is provided with an air inlet hole penetrating the transformer-coupled plasma window substrate.

[0011] The transformer coupled plasma window substrate is made of high-purity semiconductor-grade quartz ingots, wherein:

[0012] The upper surface of the transformer coupled plasma window substrate is a flat surface, and a circular mounting step is provided on the upper surface. The mounting step is concentrically arranged with the air inlet hole, and the diameter of the mounting step is larger than the diameter of the air inlet hole.

[0013] The lower surface of the transformer coupled plasma window substrate is an annular curved surface, and a spherical microstructure is formed on the lower surface through chemical etching.

[0014] Preferably, the lower surface of the transformer coupled plasma window substrate includes an inner ring area, a middle ring area and an outer ring area that are sequentially connected and smoothly transitioned from the inside to the outside, wherein the heights of the inner ring area and the outer ring area are higher than that of the middle ring area.

[0015] Preferably, the diameter of the quartz ingot is 400 mm to 600 mm, the total metal ion content is less than 500 ppm, and the hydroxyl content is less than 50 ppm.

[0016] Preferably, the flatness of the upper surface of the transformer coupled plasma window substrate is less than 0.05 mm, and the roughness is 0.15 μm to 0.20 μm; the roughness of the lower surface of the transformer coupled plasma window substrate is 1.0 μm to 1.3 μm.

[0017] The second object of the present application is to provide a method for preparing a transformer-coupled plasma window for semiconductor etching equipment as described in any one of the first objects above.

[0018] The second object of the present application is achieved through the following technical solutions:

[0019] A method for preparing a transformer-coupled plasma window for semiconductor etching equipment, the method comprising the following steps:

[0020] S1, cutting a high-purity semiconductor-grade quartz ingot having a diameter of 400 mm to 600 mm to obtain a quartz disc, and trimming a sidewall of the quartz disc, wherein the quartz disc has an upper surface and a lower surface opposite to the upper surface;

[0021] S2, machining the trimmed upper surface of the quartz disc into a flat surface as the upper surface of the transformer coupled plasma window substrate, machining an air inlet hole in the center of the quartz disc, machining a circular mounting step concentric with the air inlet hole on the upper surface of the quartz disc, and grinding and polishing the wall of the air inlet hole and the step surface of the mounting step;

[0022] S3, processing the lower surface of the ground and polished quartz disc into an annular curved surface as the lower surface of the transformer coupled plasma window substrate;

[0023] S4, machining a spherical microstructure on the lower surface of the quartz disk by chemical etching to obtain a transformer coupled plasma window.

[0024] Preferably, step S1 includes:

[0025] S11, using a diamond wire saw to horizontally cut a high-purity semiconductor-grade quartz ingot having a diameter of 400 mm to 600 mm into quartz discs having a thickness of 50 mm to 80 mm;

[0026] S12, grinding the sidewall of the quartz disc with a metal milling cutter to achieve a state without chipping and burrs.

[0027] Preferably, step S2 includes:

[0028] S21, using a surface grinder to grind the upper surface of the quartz disc to form a flat surface, wherein the flatness of the upper surface of the ground quartz disc is less than 0.05 mm and the roughness is 0.15 μm to 0.20 μm;

[0029] S22, milling the center of the upper surface of the quartz disk to form a through hole with a diameter of 5 mm to 8 mm as the air inlet hole;

[0030] S23, milling the upper surface of the quartz disc with the center of the through hole as the center of the circle to form a circular sunken step with a diameter of 40 mm to 60 mm and a depth of 20 mm as the installation step;

[0031] S24, using a wool felt grinding head and injecting 5000-10000 mesh polishing coolant at the same time, grinding and polishing the inner wall of the through hole and the inner wall and step surface of the sunken step to achieve a smooth and transparent appearance.

[0032] Preferably, step S3 includes:

[0033] S31, using a spherical metal cutter to move from the stepped opening at the center of the quartz disc toward the edge of the quartz disc, adjusting the grinding feed depth according to a preset arc profile to grind the lower surface of the quartz disc, forming an arc-shaped rough surface with a height difference, wherein the inner ring area is high, the middle ring area is low, and the outer ring area is high;

[0034] S32, using a metal grinding wheel to move from the step opening at the center of the quartz disc to the edge of the quartz disc, adjusting the grinding feed depth according to the preset arc profile to grind the arc rough surface into a smooth circular surface to form a finely machined annular surface.

[0035] Preferably, step S4 includes:

[0036] S41, performing a masking process on the other parts of the quartz disk except the annular curved surface;

[0037] S42, grinding the annular curved surface using 500-800 mesh silicon carbide abrasive to remove the processed texture, wherein after grinding, the roughness of the annular curved surface is 1.0 μm to 1.3 μm;

[0038] S43, soaking the ground quartz disk in a 10% to 20% fluorine-containing acidic etching solution for 30 to 60 minutes to etch a spherical microstructure on the annular surface;

[0039] S44, rinsing the quartz disc, removing the shielding, cleaning, and drying to obtain the transformer coupled plasma window.

[0040] Preferably, the total metal ion content of the quartz ingot is less than 500 ppm, and the hydroxyl content of the quartz ingot is less than 50 ppm.

[0041] The above technical solution of the present application has the following advantages over the prior art:

[0042] 1. The lower surface of the transformer-coupled plasma window prepared in the present application is an annular curved surface, and a spherical microstructure is formed by chemically etching the lower surface. The synergistic effect of the annular curved surface and the spherical microstructure effectively enhances the plasma adsorption capacity and the uniformity of the plasma distribution. When the ICP etching equipment performs transformer-coupled plasma etching, the lower surface of the transformer-coupled plasma window can provide stable adsorption capacity, thereby reducing the contamination of the etching chamber by particles formed by the plasma bombarding the lower surface of the transformer-coupled plasma window;

[0043] 2. During the maintenance of the etching chamber of the ICP etching equipment, by replacing the annular transformer-coupled plasma window, the process setting conditions required for normal production can be quickly achieved, significantly improving equipment utilization and reducing equipment operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 This is a schematic diagram of the three-dimensional structure of a transformer-coupled plasma window in one embodiment of the present application;

[0046] Figure 2 Schematic diagram of the upper surface structure of a transformer-coupled plasma window in one embodiment of the present application;

[0047] Figure 3 This is a schematic diagram of a radial half-section three-dimensional structure of a transformer-coupled plasma window in one embodiment of the present application;

[0048] Figure 4 This is a surface microscopic image of the lower surface of the transformer-coupled plasma window after grinding and chemical etching in one embodiment of the present application (magnification is 1000 times);

[0049] Figure 5 This is a flow chart of a method for preparing a transformer-coupled plasma window for semiconductor etching equipment in one embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to help those skilled in the art better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0051] In the embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are merely illustrative. For example, the division of units and modules is merely a logical function division. In actual implementation, there may be other division methods, such as: multiple units or modules can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0052] In addition, all functional units in the embodiments of the present application may be integrated into one processor, or each unit may be a separate device, or two or more units may be integrated into one device; each functional unit in the embodiments of the present application may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0053] Those skilled in the art will understand that all or part of the steps of the following method embodiments can be implemented by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the following method embodiments are executed; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM), magnetic disks or optical disks, and other media that can store program codes.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" or "several" means two or more, unless otherwise specifically defined.

[0055] like Figure 1-3As shown, the embodiment of the present application provides a transformer coupled plasma window for semiconductor etching equipment, the transformer coupled plasma window for semiconductor etching equipment includes a disc-shaped transformer coupled plasma window substrate, the transformer coupled plasma window substrate includes an upper surface ( Figure 1 and Figure 3 The bottom surface of Figure 2 The top surface in the figure) and the bottom surface opposite to the top surface ( Figure 1 and Figure 3 The top surface of Figure 2 The bottom surface of the transformer coupled plasma window substrate is provided with an air inlet hole ( Figure 2 The structure in 1),

[0056] The transformer coupled plasma window substrate is made of high-purity semiconductor-grade quartz ingot,

[0057] The upper surface of the transformer coupled plasma window substrate is a flat surface with a circular mounting step ( Figure 2 In structure 2), the mounting step is concentrically arranged with the air inlet hole, and the diameter of the mounting step is larger than the diameter of the air inlet hole.

[0058] The lower surface of the transformer coupled plasma window substrate is an annular curved surface ( Figure 3 The lower surface is chemically etched to form a spherical microstructure (such as Figure 4 shown).

[0059] The transformer-coupled plasma window used in the semiconductor etching equipment of this embodiment has a toroidal curved lower surface, and a spherical microstructure is formed by chemically etching the lower surface. The synergistic effect of the toroidal curved surface and the spherical microstructure effectively enhances the plasma adsorption capacity and the uniformity of the plasma distribution. When the ICP etching equipment performs transformer-coupled plasma etching, the lower surface of the transformer-coupled plasma window can provide stable adsorption capacity, thereby reducing contamination of the etching chamber by particles formed by plasma bombardment of the lower surface of the transformer-coupled plasma window.

[0060] In addition, during the maintenance of the etching chamber of the ICP etching equipment, by replacing the annular transformer-coupled plasma window, the process setting conditions required for normal production can be quickly achieved, significantly improving equipment utilization and reducing equipment operating costs.

[0061] Specifically, the transformer-coupled plasma window used in the semiconductor etching equipment of this embodiment overturns the traditional flat surface design of the plasma window lower surface and designs the plasma window lower surface into a toroidal curved surface. The special geometric shape of the toroidal curved surface optimizes the electric field distribution, reaction efficiency, or mechanical properties. The specific working mechanism of the plasma window lower surface with a spherical microstructure is as follows:

[0062] 1. Optimize the electric field and current distribution and homogenize the electric field strength

[0063] The annular plasma window can reduce the concentration of the electric field at the edge or sharp corner, avoiding local discharge or overheating. During the plasma etching process, the annular plasma window can make the plasma density more uniform by smoothing the electric field distribution, thereby improving the etching consistency.

[0064] 2. Improve reaction efficiency and energy density

[0065] The surface area of the annular curved plasma window is significantly higher than that of the flat electrode, providing more active sites. The curved surface structure can enhance the fluid dynamics and accelerate the diffusion of reactants and products.

[0066] 3. Enhance the adsorption capacity of etching by-products

[0067] The specific surface morphology of the spherical microstructure on the annular surface of the plasma window has a strong adsorption force for etching by-product particles, which can better maintain the cleanliness of the vacuum chamber of the etching equipment and reduce the chance of particle falling off.

[0068] like Figure 1 、 Figure 3 As shown, in one embodiment, the lower surface of the transformer-coupled plasma window substrate includes an inner ring region, a middle ring region, and an outer ring region, which are sequentially connected and smoothly transitioned from the inside to the outside. The inner and outer ring regions are higher than the middle ring region. The lower surface of the transformer-coupled plasma window substrate adopts an annular curved surface structure with a height difference, with the inner ring region being higher, the middle ring region being lower, and the outer ring region being higher. This effectively enhances plasma adsorption capacity and plasma distribution uniformity.

[0069] In one embodiment, the diameter of the quartz ingot is 400 mm to 600 mm, the total metal ion content is less than 500 ppm, and the hydroxyl content is less than 50 ppm. In this embodiment, high-purity, low-hydroxyl, high-temperature resistant, and low-microbubble quartz ingot blanks are selected as the quartz ingot blanks that directly contact the reaction chamber, which can be used in high-end semiconductor wafer processing technology. Preferably, in this embodiment, the total metal ion content of the quartz material is less than 100 ppm, and the hydroxyl content is less than 20 ppm. Such low-metal ion, low-carboxyl quartz blanks are just suitable for high-end semiconductor wafer processing technology.

[0070] In one embodiment, the flatness of the upper surface of the transformer coupled plasma window substrate is less than 0.05 mm, and the roughness is 0.15 μm to 0.20 μm; the roughness of the lower surface of the transformer coupled plasma window substrate is 1.0 μm to 1.3 μm.

[0071] Such surface roughness and flatness can better meet the needs of high-end semiconductor wafer manufacturing processes and more effectively enhance plasma adsorption capacity and uniformity of plasma distribution.

[0072] Example 1 of the present application further provides a method for preparing a transformer-coupled plasma window for semiconductor etching equipment, which may include the following steps:

[0073] S1, cutting a high-purity semiconductor-grade quartz ingot with a diameter of 400 mm to 600 mm to obtain a quartz disc, and trimming the sidewall of the quartz disc, wherein the quartz disc has an upper surface and a lower surface opposite to the upper surface;

[0074] S2, machining the upper surface of the trimmed quartz disc into a flat surface as the upper surface of the transformer-coupled plasma window substrate, machining an air inlet hole in the center of the quartz disc, machining a circular mounting step concentric with the air inlet hole on the upper surface of the quartz disc, and grinding and polishing the wall of the air inlet hole and the step surface of the mounting step;

[0075] S3, processing the lower surface of the ground and polished quartz disk into an annular curved surface as the lower surface of the transformer coupled plasma window substrate;

[0076] S4, a spherical microstructure is machined on the lower surface of the quartz disk by chemical etching to obtain a transformer coupled plasma window.

[0077] In this embodiment, through the above process flow, a transformer coupled plasma window for semiconductor etching equipment that meets the target requirements can be easily and quickly prepared. The process flow is simple and facilitates the industrialization of product production.

[0078] The transformer-coupled plasma window for semiconductor etching equipment prepared by this process has a ring-shaped curved surface on its lower surface, and a spherical microstructure is formed by chemically etching the lower surface. The synergistic effect of the ring-shaped curved surface and the spherical microstructure effectively enhances the plasma adsorption capacity and the uniformity of the plasma distribution. When transformer-coupled plasma etching is performed in an ICP etching device, the lower surface of the transformer-coupled plasma window can provide stable adsorption capacity, thereby reducing the contamination of the etching chamber by particles formed by plasma bombardment on the lower surface of the transformer-coupled plasma window.

[0079] In addition, during the maintenance of the etching chamber of the ICP etching equipment, by replacing the transformer-coupled plasma window with an annular curved surface prepared by this process, the process setting conditions required for normal production can be quickly achieved, significantly improving equipment utilization and reducing equipment operating costs.

[0080] In one embodiment, step S1 includes:

[0081] S11, using a diamond wire saw to horizontally cut a high-purity semiconductor-grade quartz ingot having a diameter of 400 mm to 600 mm into quartz discs having a thickness of 50 mm to 80 mm;

[0082] S12, grinding the side wall of the quartz disc by a metal milling cutter to achieve a state without chipping and burrs.

[0083] In one embodiment, step S2 includes:

[0084] S21, using a surface grinder to grind the upper surface of the quartz disc to form a flat surface, wherein the flatness of the upper surface of the ground quartz disc is less than 0.05 mm and the roughness is 0.15 μm to 0.20 μm;

[0085] S22, milling the center of the upper surface of the quartz disk to form a through hole with a diameter of 5 mm to 8 mm as an air intake hole;

[0086] S23, milling the upper surface of the quartz disc with the center of the through hole as the center of the circle to form a circular sunken step with a diameter of 40 mm to 60 mm and a depth of 20 mm as the installation step;

[0087] S24, using a wool felt grinding head and injecting 5000-10000 mesh polishing coolant, grind and polish the inner wall of the through hole and the inner wall and step surface of the sunken step to achieve a smooth and transparent appearance.

[0088] In one embodiment, step S3 includes:

[0089] S31, using a spherical metal cutter to move from the stepped opening in the center of the quartz disc toward the edge of the quartz disc, adjusting the grinding feed depth according to a preset arc profile to grind the lower surface of the quartz disc, forming an arc-shaped rough surface with a height difference, wherein the inner ring area is high, the middle ring area is low, and the outer ring area is high;

[0090] S32: Use a metal grinding wheel to move from the step opening in the center of the quartz disc to the edge of the quartz disc, adjust the grinding feed depth according to the preset arc profile, and grind the arc rough surface into a smooth circular surface to form a finely machined annular surface.

[0091] In one embodiment, step S4 includes:

[0092] S41, performing masking processing on the other parts of the quartz disk except the annular curved surface;

[0093] S42, grinding the annular surface using 500-800 mesh silicon carbide abrasive to remove the processed texture. After grinding, the roughness of the annular surface is 1.0 μm to 1.3 μm.

[0094] S43, soaking the ground quartz disk in a 10% to 20% fluorine-containing acidic etching solution for 30 to 60 minutes to etch a spherical microstructure on the annular surface;

[0095] S44, rinsing the quartz disc, removing the shielding, cleaning, and drying to obtain a transformer coupled plasma window.

[0096] In one embodiment, the total metal ion content of the quartz ingot is less than 500 ppm, and the hydroxyl content of the quartz ingot is less than 50 ppm.

[0097] In order to better understand the specific preparation process and advantages of the transformer-coupled plasma window for semiconductor etching equipment in the embodiment of the present application, its preparation process and advantages are described below using a specific example.

[0098] In this example, the preparation process of the transformer coupled plasma window for semiconductor etching equipment is as follows:

[0099] Step 1: Selecting a semiconductor-grade quartz ingot with high purity, low hydroxyl content, high temperature resistance, and few microbubbles as the processing blank for the transformer-coupled plasma window, wherein the quartz ingot is preferably of a grade with a total metal ion content of <500 ppm and a hydroxyl content of <50 ppm;

[0100] Step 2: Slice the quartz ingot of the selected specifications and use a diamond wire cutter to horizontally cut the quartz ingot at a cutting speed of 5 mm / min. Cut the quartz ingot into quartz discs with a thickness of 60 mm. Then use a 325# metal milling cutter to grind the side walls of the quartz discs to achieve a state without chipping and burrs.

[0101] Step 3: Smooth the upper surface of the quartz disc. After waxing the quartz disc, place it in a flat grinder for leveling. After leveling, the surface roughness Ra is 0.15 μm to 0.20 μm, and the flatness is <0.05 mm.

[0102] Step 4: Mill the center of the upper surface of the quartz disc to form an 8mm diameter through-hole as the air intake hole. Use a 500# milling cutter to form a 60mm diameter and 20mm deep sunken step in the center of the quartz disc as the installation step.

[0103] Step 5: Use wool felt as the grinding material for the grinding head to polish the inner wall of the air intake hole and the inner wall and step surface of the mounting step, inject 8000-mesh alumina polishing coolant, and set the machining spindle-linked wool felt grinding head at a high speed of 4000 r / min to perform physical polishing on the inner wall of the air intake hole and the step surface of the mounting step. The surface roughness Ra of the air intake hole after treatment is 0.03 μm to 0.05 μm, the surface is transparent, without scratches or bubbles;

[0104] Step 6: Remove the quartz disc from the turntable, remove the wax, fix the processed upper surface with wax, and process the lower surface;

[0105] Step 7: Set the turntable speed to 100 rpm. After tool setting, use a customized metal cutter to move from the step edge of the quartz disc's mounting step to the edge of the quartz disc. The feed speed is 0.3 mm / min, which is equivalent to a feed amount of 0.003 mm per circle. Adjust the grinding feed depth of the spherical metal cutter along the axial direction of the quartz disc according to the preset arc profile control curve to form different grinding amounts on the disc, thereby forming an arc-shaped rough surface. Then, replace the metal cutter with an #800 metal grinding wheel, and use the grinding head to grind the arc-shaped rough surface into a smooth surface to form a finished annular surface.

[0106] Step 8: Remove the quartz disc from the turntable, dewax it, and clean it with a 3% degreasing agent to remove the cutting fluid;

[0107] Step 9: Protect the quartz disc by masking it with acid-proof tape on the top and sides, and using silicone plugs to cover the air inlet holes and mounting steps, leaving only the annular curved surface exposed.

[0108] Step 10: Fix the quartz disc on a turntable, set the rotation speed to 20 r / min, and grind the annular surface with 500-mesh silicon carbide abrasive to remove the processing texture. After grinding, the surface roughness Ra reaches 1.0 μm to 1.3 μm.

[0109] Step 11: Soak the quartz disc in 15% HF solution for 60 minutes to etch a round spherical microstructure, then rinse with pure water to remove the masking material, first ultrasonically clean for 15 minutes, then rinse with ultrapure water, and then dry to remove surface moisture to obtain the final product.

[0110] The comparison results of the recovery time and the number of wafers preset for the transformer-coupled plasma window for semiconductor etching equipment prepared in this example and the conventional transformer-coupled plasma window in the prior art are shown in the following table:

[0111]

[0112]

[0113] By comparison, by replacing the traditional flat TCP window with the annular curved TCP window of this application, the restart time is reduced from the original 20RF to 12RF, and the number of preheated wafers on the machine is reduced from 70 to 36, which greatly shortens the restart time and reduces the restart cost.

[0114] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0115] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this embodiment can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0116] The steps of the methods or algorithms described in conjunction with the embodiments disclosed in this embodiment can be implemented directly using hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art.

[0117] The above description of the disclosed embodiments is intended to enable those skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this embodiment may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not limited to the embodiments shown in this example, but is intended to conform to the widest scope consistent with the principles and novel features disclosed in this embodiment.

Claims

1. A transformer-coupled plasma window for semiconductor etching equipment, comprising a disc-shaped transformer-coupled plasma window substrate, the transformer-coupled plasma window substrate comprising an upper surface and a lower surface opposite to the upper surface, the lower surface being the side facing the electrostatic chuck in the etching chamber when installed, and an air inlet through-hole penetrating the transformer-coupled plasma window substrate being provided at the center of the transformer-coupled plasma window substrate, characterized in that: The transformer coupled plasma window substrate is made of high-purity semiconductor-grade quartz ingots, wherein: The upper surface of the transformer coupled plasma window substrate is a flat surface, and a circular mounting step is provided on the upper surface. The mounting step is concentrically arranged with the air inlet hole, and the diameter of the mounting step is larger than the diameter of the air inlet hole. The lower surface of the transformer coupled plasma window substrate is an annular curved surface, and a spherical microstructure is formed on the lower surface through chemical etching.

2. The transformer coupled plasma window for semiconductor etching equipment according to claim 1, wherein: The lower surface of the transformer coupled plasma window substrate includes an inner ring area, a middle ring area and an outer ring area that are sequentially connected and smoothly transitioned from the inside to the outside, wherein the heights of the inner ring area and the outer ring area are higher than that of the middle ring area.

3. The transformer coupled plasma window for semiconductor etching equipment according to claim 1, wherein: The diameter of the quartz ingot is 400 mm to 600 mm, the total metal ion content is less than 500 ppm, and the hydroxyl content is less than 50 ppm.

4. The transformer coupled plasma window for semiconductor etching equipment according to claim 1, wherein: The flatness of the upper surface of the transformer coupled plasma window substrate is less than 0.05 mm, and the roughness is 0.15 μm to 0.20 μm; the roughness of the lower surface of the transformer coupled plasma window substrate is 1.0 μm to 1.3 μm.

5. A method for preparing a transformer coupled plasma window for semiconductor etching equipment according to claim 1, characterized in that: The steps include: S1, cutting a high-purity semiconductor-grade quartz ingot having a diameter of 400 mm to 600 mm to obtain a quartz disc, and trimming a sidewall of the quartz disc, wherein the quartz disc has an upper surface and a lower surface opposite to the upper surface; S2, machining the trimmed upper surface of the quartz disc into a flat surface as the upper surface of the transformer coupled plasma window substrate, machining an air inlet hole in the center of the quartz disc, machining a circular mounting step concentric with the air inlet hole on the upper surface of the quartz disc, and grinding and polishing the wall of the air inlet hole and the step surface of the mounting step; S3, processing the lower surface of the ground and polished quartz disc into an annular curved surface as the lower surface of the transformer coupled plasma window substrate; S4, machining a spherical microstructure on the lower surface of the quartz disk by chemical etching to obtain a transformer coupled plasma window.

6. The method for preparing a transformer coupled plasma window for semiconductor etching equipment according to claim 5, wherein: Step S1 includes: S11, using a diamond wire saw to horizontally cut a high-purity semiconductor-grade quartz ingot having a diameter of 400 mm to 600 mm into quartz discs having a thickness of 50 mm to 80 mm; S12, grinding the sidewall of the quartz disc with a metal milling cutter to achieve a state without chipping and burrs.

7. The method for preparing a transformer coupled plasma window for semiconductor etching equipment according to claim 5, wherein: Step S2 includes: S21, using a surface grinder to grind the upper surface of the quartz disc to form a flat surface, wherein the flatness of the upper surface of the ground quartz disc is less than 0.05 mm and the roughness is 0.15 μm to 0.20 μm; S22, milling the center of the upper surface of the quartz disk to form a through hole with a diameter of 5 mm to 8 mm as the air inlet hole; S23, milling the upper surface of the quartz disc with the center of the through hole as the center of the circle to form a circular sunken step with a diameter of 40 mm to 60 mm and a depth of 20 mm as the installation step; S24, using a wool felt grinding head and injecting 5000-10000 mesh polishing coolant at the same time, grinding and polishing the inner wall of the through hole and the inner wall and step surface of the sunken step to achieve a smooth and transparent appearance.

8. The method for preparing a transformer coupled plasma window for semiconductor etching equipment according to claim 5, wherein: Step S3 includes: S31, using a spherical metal cutter to move from the stepped opening at the center of the quartz disc toward the edge of the quartz disc, adjusting the grinding feed depth according to a preset arc profile to grind the lower surface of the quartz disc, forming an arc-shaped rough surface with a height difference, wherein the inner ring area is high, the middle ring area is low, and the outer ring area is high; S32, using a metal grinding wheel to move from the step opening at the center of the quartz disc to the edge of the quartz disc, adjusting the grinding feed depth according to the preset arc profile to grind the arc rough surface into a smooth circular surface to form a finely machined annular surface.

9. The method for preparing a transformer coupled plasma window for semiconductor etching equipment according to claim 5, wherein: Step S4 includes: S41, performing a masking process on the other parts of the quartz disk except the annular curved surface; S42, grinding the annular curved surface using 500-800 mesh silicon carbide abrasive to remove the processed texture, wherein after grinding, the roughness of the annular curved surface is 1.0 μm to 1.3 μm; S43, soaking the ground quartz disk in a 10% to 20% fluorine-containing acidic etching solution for 30 to 60 minutes to etch a spherical microstructure on the annular surface; S44, rinsing the quartz disc, removing the shielding, cleaning, and drying to obtain the transformer coupled plasma window.

10. The method for preparing a transformer coupled plasma window for semiconductor etching equipment according to any one of claims 5 to 9, characterized in that: The total metal ion content of the quartz ingot is less than 500 ppm, and the hydroxyl content of the quartz ingot is less than 50 ppm.

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