Transformer coupled plasma window for semiconductor etching apparatus and method of making same
By designing an annular curved surface on the lower surface of the TCP window and forming a spherical microstructure, the problems of uneven plasma adsorption and long rework time were solved, enabling more efficient operation of the etching equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING GENORI IND CO LTD
- Filing Date
- 2025-05-07
- Publication Date
- 2026-05-15
AI Technical Summary
The traditional TCP window has a flat lower surface design, which leads to uneven plasma adsorption, high risk of etching cavity contamination, long reactivation time, and high maintenance costs.
The transformer-coupled plasma window adopts a toroidal curved surface design, and the lower surface is formed into a spherical microstructure through chemical etching, which enhances the plasma adsorption capacity and distribution uniformity, and optimizes the electric field distribution.
It improves the uniformity of plasma distribution, reduces contamination in the etching cavity, shortens equipment restart time, and lowers operating costs.
Smart Images
Figure CN120453149B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor etching equipment technology, and in particular to a transformer-coupled plasma window for semiconductor etching equipment and its preparation method. Background Technology
[0002] Inductively Coupled Plasma (ICP) 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 output generated by the ICP RF power supply is sent to a ring coupling coil. The gas mixed in a certain proportion is coupled and glow discharge to generate high-density plasma. This plasma bombards the surface of the silicon wafer, breaking the chemical bonds of the silicon material. The plasma reacts with the etching gas to generate byproducts, which are then removed from the silicon wafer in gaseous form and thus achieve the etching effect.
[0003] ICP etching equipment boasts advantages such as high precision and high speed, and is widely used for etching materials such as silicon, silicon nitride, oxides, and metals. The TCP (Transformer Coupled Plasma) window is a crucial component of this equipment. It receives the etching gas from the plasma etching chamber while simultaneously adsorbing and depositing complex byproduct particles such as silicon oxides and metal oxides generated during the etching process, maintaining the cleanliness of the etching chamber. In actual silicon wafer processing, to ensure process stability, various key components within the ICP equipment, including the TCP window, need to be replaced periodically. After component replacement, the equipment undergoes a pre-run. Once the parameters set within the etching chamber reach their targets, silicon wafer production commences.
[0004] Traditional TCP windows feature a standardized flat surface design with a central hole (both the upper and lower surfaces are flat). The flat surface with a certain degree of roughness faces the electrostatic chuck for assembly, and is etched by plasma during the etching process. Traditional TCP windows have the following drawbacks in actual production:
[0005] 1. The traditional TCP window has a flat surface design on the side facing the electrostatic chuck (lower surface), and the surface treatment mostly relies on physical grinding, which makes it difficult to form a uniform micro-morphology, affecting the uniformity of plasma distribution, and resulting in insufficient plasma adsorption capacity. This leads to uneven deposition of by-product particles and a high risk of contamination of the etching cavity.
[0006] 2. The traditional TCP window has 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 stable equipment operation (i.e., restart time) is long, resulting in high equipment maintenance costs. Summary of the Invention
[0007] To address the aforementioned technical problems, this application provides a transformer-coupled plasma window for semiconductor etching equipment and its fabrication method, thereby solving the problems of uneven plasma adsorption, long rework time, and high maintenance costs caused by the planar design of the lower surface of the traditional TCP window.
[0008] The first objective of this application is to provide a transformer-coupled plasma window for a semiconductor etching apparatus.
[0009] The aforementioned objective of this application is achieved through the following technical solution:
[0010] A transformer-coupled plasma window for a semiconductor etching apparatus includes a disk-shaped transformer-coupled plasma window substrate. The substrate includes an upper surface and a lower surface opposite to the upper surface. The lower surface faces an electrostatic chuck inside the etching cavity during installation. An air inlet hole penetrating the substrate is located at the center of the transformer-coupled plasma window substrate.
[0011] The transformer-coupled plasma window substrate is made of high-purity semiconductor-grade quartz ingot, 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 the lower surface is formed with a spherical microstructure by chemical etching.
[0014] Preferably, the lower surface of the transformer-coupled plasma window substrate includes an inner ring region, a middle ring region, and an outer ring region that are connected sequentially from the inside to the outside and smoothly transitioned, wherein the height of the inner ring region and the outer ring region is higher than the height of the middle ring region.
[0015] Preferably, the diameter of the quartz ingot is 400mm to 600mm, the total metal ion content is <500ppm, and the hydroxyl content is <50ppm.
[0016] Preferably, the flatness of the upper surface of the transformer-coupled plasma window substrate is <0.05mm, and the roughness is 0.15μm to 0.20μm; the roughness of the lower surface of the transformer-coupled plasma window substrate is 1.0μm to 1.3μm.
[0017] The second objective of this application is to provide a method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus as described in any of the first objectives above.
[0018] The second objective of this application is achieved through the following technical solution:
[0019] A method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus, the method comprising the following steps:
[0020] S1, a high-purity semiconductor-grade quartz ingot with a diameter of 400mm to 600mm is cut to obtain a quartz disk, and the sidewall of the quartz disk is trimmed. The quartz disk has an upper surface and a lower surface opposite to the upper surface.
[0021] S2, the upper surface of the quartz disk after trimming is processed into a flat surface as the upper surface of the transformer coupling plasma window substrate, and an air inlet hole is processed in the center of the quartz disk. A circular mounting step concentric with the air inlet hole is processed on the upper surface of the quartz disk, and the hole wall of the air inlet hole and the step surface of the mounting step are ground and polished.
[0022] S3, the lower surface of the polished quartz disk is processed into an annular curved surface to serve as the lower surface of the transformer coupling plasma window substrate;
[0023] S4. A spherical microstructure is formed 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 cutter to horizontally cut high-purity semiconductor-grade quartz ingots with a diameter of 400mm to 600mm into quartz discs with a thickness of 50mm to 80mm;
[0026] S12, the sidewall of the quartz disk is ground with a metal milling cutter to achieve a state without chipping or burrs.
[0027] Preferably, step S2 includes:
[0028] S21, the upper surface of the quartz disk is ground flat using a surface grinder to form a flat surface. The flatness of the upper surface of the ground quartz disk is <0.05mm and the roughness is 0.15μm~0.20μm.
[0029] S22, the center of the upper surface of the quartz disk is milled to create a through hole with a diameter of 5mm to 8mm as the air inlet hole.
[0030] S23, with the center of the through hole as the center, the upper surface of the quartz disk is milled to create a circular recessed step with a diameter of 40mm to 60mm and a depth of 20mm as the mounting step;
[0031] S24. Using a wool felt grinding head, and simultaneously injecting 5000-10000 grit polishing coolant, the inner wall of the through hole and the inner wall and step surface of the sunken step are ground and polished to achieve a smooth and transparent appearance.
[0032] Preferably, step S3 includes:
[0033] S31, using a spherical metal cutter, the blade moves from the stepped opening at the center of the quartz disk to the edge of the quartz disk, and the grinding feed depth is adjusted according to the preset arc contour to grind the lower surface of the quartz disk, forming an arc-shaped rough surface with a height difference, where 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, move from the stepped opening at the center of the quartz disk to the edge of the quartz disk, and adjust the grinding feed depth according to the preset arc contour to grind the arc rough surface into a finely machined annular curved surface.
[0035] Preferably, step S4 includes:
[0036] S41, the parts of the quartz disk other than the annular curved surface are shielded;
[0037] S42, the annular surface is ground using 500-800 mesh silicon carbide abrasive to remove the processing texture. After grinding, the roughness of the annular surface is 1.0μm-1.3μm.
[0038] S43, the quartz disk after grinding is immersed in a solution of 10% to 20% fluorine-containing acidic etching solution for 30 min to 60 min to etch the annular curved surface into a spherical micromorphology.
[0039] S44, the quartz disk is rinsed to remove the shielding, then cleaned and dried to obtain the transformer-coupled plasma window.
[0040] Preferably, the total metal ion content of the quartz ingot is <500ppm, and the hydroxyl content of the quartz ingot is <50ppm.
[0041] The technical solution described in this application has the following advantages over the prior art:
[0042] 1. The lower surface of the transformer-coupled plasma window prepared in this application is an annular curved surface, and a spherical microstructure is formed by chemical etching of the lower surface. Through the synergistic effect of the annular curved surface and the spherical microstructure, the plasma adsorption capacity and the uniformity of plasma distribution are effectively enhanced. When the transformer-coupled plasma is etched in the ICP etching equipment, the lower surface of the transformer-coupled plasma window can provide a stable adsorption capacity, thereby reducing the contamination of the etching cavity by particles formed by the bombardment of the lower surface of the transformer-coupled plasma window by the plasma.
[0043] 2. During the maintenance of the etching chamber of the ICP etching equipment, by replacing the annular curved surface 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. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 This is a three-dimensional structural schematic diagram of a transformer-coupled plasma window in one embodiment of this application;
[0046] Figure 2 This is a schematic diagram of the upper surface structure of the transformer-coupled plasma window in one embodiment of this application;
[0047] Figure 3 This is a radial half-section perspective view of the three-dimensional structure of the transformer-coupled plasma window in one embodiment of this application;
[0048] Figure 4 This is a microscopic image of the lower surface of the transformer-coupled plasma window in one embodiment of this application after grinding and chemical etching (magnification of 1000x).
[0049] Figure 5 This is a flowchart of a method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to an embodiment of this application. Detailed Implementation
[0050] To enable those skilled in the art to 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 described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are 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 only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or modules can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.
[0052] In addition, each functional unit in the various embodiments of this application can be integrated into a single processor, or each unit can be a separate device, or two or more units can be integrated into a single device; each functional unit in the various embodiments of this application can be implemented in 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, they perform the steps of the following method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.
[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.
[0055] like Figure 1-3As shown, this application embodiment provides a transformer-coupled plasma window for a semiconductor etching apparatus. The transformer-coupled plasma window includes a disk-shaped substrate, and the substrate includes an upper surface (…). Figure 1 and Figure 3 The bottom surface of the middle Figure 2 The top surface and the bottom surface opposite to the top surface. Figure 1 and Figure 3 The top surface of the middle Figure 2 The bottom surface of the transformer coupling plasma window substrate faces the electrostatic chuck inside the etching cavity during installation. The center of the transformer coupling plasma window substrate has an air inlet hole that penetrates the entire substrate. Figure 2 Structure 1) in the middle,
[0056] The transformer-coupled plasma window substrate is fabricated from high-purity semiconductor-grade quartz ingots, wherein...
[0057] 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. Figure 2 Structure 2) features a mounting step that is concentric with the air intake hole, with the diameter of the mounting step being larger than the diameter of the air intake hole.
[0058] The lower surface of the transformer-coupled plasma window substrate is an annular curved surface. Figure 3 Structure 3), the lower surface has a spherical microstructure formed by chemical etching (such as Figure 4 (As shown).
[0059] The transformer-coupled plasma window used in the semiconductor etching equipment in this embodiment has a toroidal curved surface on its lower surface. A spherical microstructure is formed on the lower surface by chemical etching. Through the synergistic effect of the toroidal curved surface and the spherical microstructure, the plasma adsorption capacity and the uniformity of plasma distribution are effectively enhanced. When the transformer-coupled plasma etching is performed in the ICP etching equipment, the lower surface of the transformer-coupled plasma window can provide a stable adsorption capacity, thereby reducing the contamination of the etching cavity by particles formed by the bombardment of the lower surface of the transformer-coupled plasma window by the plasma.
[0060] In addition, during the maintenance of the etching chamber of the ICP etching equipment, by replacing the annular curved 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 this example of semiconductor etching equipment, by subverting the traditional flat surface design of the lower surface of the plasma window, designs the lower surface of the plasma window as a toroidal surface. The special geometry of the toroidal surface optimizes the electric field distribution, reaction efficiency, or mechanical properties. The specific working mechanism of the toroidal surface of the plasma window with a spherical microstructure is as follows:
[0062] I. Optimize electric field and current distribution to homogenize electric field intensity
[0063] The toroidal plasma window can reduce the concentration of electric field at the edges or sharp corners, avoiding partial discharge or overheating. During plasma etching, the toroidal plasma window smooths the electric field distribution, making the plasma density more uniform and improving etching consistency.
[0064] II. Improving reaction efficiency and energy density
[0065] The surface area of the plasma window on the toroidal surface is significantly larger than that of the planar electrode, providing more active sites. Furthermore, the curved structure enhances hydrodynamic properties and accelerates the diffusion of reactants / products.
[0066] III. Enhanced adsorption capacity for etching byproducts
[0067] The spherical microstructure on the annular surface of the plasma window has a specific surface morphology that strongly adsorbs etching byproduct particles, which can better maintain the cleanliness of the vacuum chamber of the etching equipment and reduce the probability of particle detachment.
[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 that are connected sequentially from the inside out and smoothly transitioned, wherein the height of the inner ring region and the outer ring region is higher than the height of the middle ring region. The lower surface of the transformer-coupled plasma window substrate adopts an annular curved surface arc structure with a height difference, where the inner ring region is high, the middle ring region is low, and the outer ring region is high, which can effectively enhance the plasma adsorption capacity and the uniformity of plasma distribution.
[0069] In one embodiment, the quartz ingot has a diameter of 400mm to 600mm, a total metal ion content of <500ppm, and a hydroxyl content of <50ppm. In this embodiment, a high-purity, low-hydroxyl, high-temperature resistant, and low-microbubble quartz ingot blank is selected as the direct contact material with the reaction chamber, which can be used in high-end semiconductor wafer fabrication processes. Preferably, in this embodiment, the quartz material has a total metal ion content of <100ppm and a hydroxyl content of <20ppm. Such a low-metal-ion, low-carboxyl-group quartz blank is perfectly suited for high-end semiconductor wafer fabrication processes.
[0070] In one embodiment, the flatness of the upper surface of the transformer-coupled plasma window substrate is <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 requirements of high-end semiconductor wafer manufacturing processes, and more effectively enhance plasma adsorption capacity and plasma distribution uniformity.
[0072] Embodiment 1 of this application also provides a method for fabricating a transformer-coupled plasma window for a semiconductor etching device, which may include the following steps:
[0073] S1. A high-purity semiconductor-grade quartz ingot with a diameter of 400mm to 600mm is cut to obtain a quartz disk, and the sidewall of the quartz disk is trimmed. The quartz disk has an upper surface and a lower surface opposite to the upper surface.
[0074] S2, the upper surface of the quartz disk after trimming is processed into a flat surface to serve as the upper surface of the transformer coupling plasma window substrate, and an air inlet hole is processed in the center of the quartz disk. A circular mounting step concentric with the air inlet hole is processed on the upper surface of the quartz disk, and the hole wall of the air inlet hole and the step surface of the mounting step are ground and polished.
[0075] S3, the lower surface of the polished quartz disk is processed into an annular curved surface to serve as the lower surface of the transformer-coupled plasma window substrate;
[0076] S4, a spherical microstructure is formed on the lower surface of a quartz disk by chemical etching to obtain a transformer-coupled plasma window.
[0077] In this embodiment, the above process can be used to easily and quickly prepare a transformer-coupled plasma window for semiconductor etching equipment that meets the target requirements. The process is simple and facilitates the industrialization of product manufacturing.
[0078] The transformer-coupled plasma window for semiconductor etching equipment prepared by this process has a toroidal curved surface on its lower surface. A spherical microstructure is formed on the lower surface by chemical etching. Through the synergistic effect of the toroidal curved surface and the spherical microstructure, the plasma adsorption capacity and the uniformity of plasma distribution are effectively enhanced. When performing transformer-coupled plasma etching in ICP etching equipment, the lower surface of the transformer-coupled plasma window can provide a stable adsorption capacity, thereby reducing the contamination of the etching cavity by particles formed by the bombardment of the lower surface of the transformer-coupled plasma window by plasma.
[0079] In addition, during the maintenance of the etching chamber of the ICP etching equipment, by replacing the transformer-coupled plasma window with the 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 cutter to horizontally cut high-purity semiconductor-grade quartz ingots with a diameter of 400mm to 600mm into quartz discs with a thickness of 50mm to 80mm;
[0082] S12 uses a metal milling cutter to grind the sidewall of the quartz disk to achieve a state without chipping or burrs.
[0083] In one embodiment, step S2 includes:
[0084] S21. The upper surface of the quartz disk is ground flat using a surface grinder to form a flat surface. The flatness of the upper surface of the ground quartz disk is <0.05mm and the roughness is 0.15μm~0.20μm.
[0085] S22, the center of the upper surface of the quartz disk is milled to create a through hole with a diameter of 5mm to 8mm as an air inlet.
[0086] S23. Using the center of the through hole as the center, mill the upper surface of the quartz disk to create a circular recessed step with a diameter of 40mm to 60mm and a depth of 20mm as the installation step.
[0087] S24 uses a wool felt grinding head and injects 5000-10000 grit polishing coolant to grind and polish the inner wall of the through hole and the inner wall and step surface of the recessed step to achieve a smooth and transparent appearance.
[0088] In one embodiment, step S3 includes:
[0089] S31, using a spherical metal cutter, the blade moves from the stepped opening at the center of the quartz disk to the edge of the quartz disk, and the grinding feed depth is adjusted according to the preset arc contour to grind the lower surface of the quartz disk, forming an arc-shaped rough surface with a height difference, where the inner ring area is high, the middle ring area is low, and the outer ring area is high.
[0090] S32, using a metal grinding wheel, moves from the stepped opening at the center of the quartz disk to the edge of the quartz disk, adjusting the grinding feed depth according to the preset arc contour to grind the arc rough surface into a finely machined annular curved surface.
[0091] In one embodiment, step S4 includes:
[0092] S41, to shield the parts of the quartz disk except for the annular curved surface;
[0093] S42, the annular surface is ground using 500-800 mesh silicon carbide abrasive to remove machining texture. After grinding, the roughness of the annular surface is 1.0μm-1.3μm.
[0094] S43, the polished quartz disk is immersed in a 10% to 20% fluorine-containing acidic etching solution for 30 to 60 minutes to etch a spherical micromorphology into the annular curved surface.
[0095] S44. Rinse the quartz disk to remove the shielding, then clean and dry it to obtain the transformer-coupled plasma window.
[0096] In one embodiment, the total metal ion content of the quartz ingot is <500ppm, and the hydroxyl content of the quartz ingot is <50ppm.
[0097] To better understand the specific fabrication process and advantages of the transformer-coupled plasma window for semiconductor etching equipment according to the embodiments of this application, the fabrication process and advantages are described below with a specific example.
[0098] In this example, the fabrication process of the transformer-coupled plasma window for the semiconductor etching equipment is as follows:
[0099] Step 1: Select high-purity, low-hydroxyl, high-temperature resistant, and low-microbubble semiconductor-grade quartz ingots as the processing blanks for the transformer coupling plasma window. Among them, quartz ingots with a total metal ion content of <500ppm and a hydroxyl content of <50ppm are preferred.
[0100] Step 2: Slice the selected quartz ingots. Use a diamond wire cutter to cut the quartz ingots horizontally at a cutting speed of 5mm / min to cut the quartz ingots into quartz discs with a thickness of 60mm. Then use a 325# metal milling cutter to grind the side walls of the quartz discs to achieve a state without chipping or burrs.
[0101] Step 3: Flatten the upper surface of the quartz disk. After the quartz disk is fixed with wax, it is placed in a surface grinding machine for flattening. After flattening, the surface roughness Ra is 0.15μm~0.20μm and the flatness is <0.05mm.
[0102] Step 4: Mill the center of the upper surface of the quartz disk to create an 8mm diameter through hole as an air inlet. Then, use a 500# milling cutter to machine a recessed step with a diameter of 60mm and a depth of 20mm as an installation step at the center of the quartz disk.
[0103] Step 5: Using wool felt as the grinding material, polish the inner wall of the air inlet hole and the inner wall and step surface of the mounting step. Inject 8000-mesh alumina polishing coolant. Set the wool felt grinding head of the machining spindle to a high speed of 4000 r / min to perform physical polishing on the inner wall of the air inlet hole and the step surface of the mounting step. The surface roughness Ra of the air inlet hole after treatment is 0.03μm~0.05μm, the surface is transparent, without scratches, and without bubbles.
[0104] Step 6: Remove the quartz disc from the turntable, remove the wax, then apply wax to the processed upper surface to fix it, and process the lower surface.
[0105] Step 7: Set the turntable speed to 100 r / min. After tool setting, use a custom metal cutter to move from the step opening of the mounting step of the quartz disk to the edge of the quartz disk. The feed speed is 0.3 mm / min, which is equivalent to a feed amount of 0.003 mm per revolution. Adjust the grinding feed depth of the spherical metal cutter along the axial direction of the quartz disk according to the preset arc contour control curve to form different grinding amounts on the disk, thereby forming an arc rough surface. Then replace the metal cutter with a #800 metal grinding wheel and use the grinding head to grind the arc rough surface smoothly to form a finished annular curved surface.
[0106] Step 8: Remove the quartz disc from the turntable, remove the wax, and clean the quartz disc with a 3% degreaser to remove the cutting fluid.
[0107] Step 9: Protect the quartz disc by covering the upper surface and sides of the quartz disc with acid-resistant tape, and cover the air inlet and mounting steps with silicone plugs, leaving only the annular curved area exposed.
[0108] Step 10: Fix the quartz disk on the turntable, set the rotation speed to 20 r / min, and use 500-mesh silicon carbide abrasive to grind the annular surface 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 disk in 15% HF solution for 60 minutes to etch out a spherical microstructure. Then rinse with pure water to remove the masking material. First, ultrasonically clean for 15 minutes, then rinse with ultrapure water to clean it. Finally, dry to remove surface moisture to obtain the final product.
[0110] The following table compares the reset time and the preset number of wafers for the semiconductor etching equipment using the transformer-coupled plasma window prepared in this example with those of the conventional transformer-coupled plasma window in the prior art:
[0111]
[0112]
[0113] By comparison, by replacing the traditional flat TCP window with the circular curved TCP window of this application, the reactivation time was reduced from 20RF to 12RF, and the number of preheated wafers on the machine was reduced from 70 to 36, which significantly shortened the reactivation time and reduced the reactivation cost.
[0114] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.
[0115] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered 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, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.
[0117] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in these embodiments may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A transformer-coupled plasma window for a semiconductor etching apparatus, comprising a disk-shaped transformer-coupled plasma window substrate, the transformer-coupled plasma window substrate including an upper surface and a lower surface opposite to the upper surface, the lower surface being the side facing an electrostatic chuck inside the etching cavity during installation, and an air inlet 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 ingot, 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. The lower surface of the transformer-coupled plasma window substrate includes an inner ring region, a middle ring region, and an outer ring region that are connected sequentially from the inside out and smoothly transitioned. The height of the inner ring region and the outer ring region is higher than the height of the middle ring region.
2. The transformer-coupled plasma window for semiconductor etching equipment according to claim 1, characterized in that, The quartz ingot has a diameter of 400mm~600mm, a total metal ion content of <500ppm, and a hydroxyl content of <50ppm.
3. The transformer-coupled plasma window for semiconductor etching equipment according to claim 1, characterized in that, The flatness of the upper surface of the transformer-coupled plasma window substrate is <0.05mm, and the roughness is 0.15μm~0.20μm; the roughness of the lower surface of the transformer-coupled plasma window substrate is 1.0μm~1.3μm.
4. A method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus as described in claim 1, characterized in that, Includes the following steps: S1, a high-purity semiconductor-grade quartz ingot with a diameter of 400mm~600mm is cut to obtain a quartz disk, and the sidewall of the quartz disk is trimmed. The quartz disk has an upper surface and a lower surface opposite to the upper surface. S2, the upper surface of the quartz disk after trimming is processed into a flat surface as the upper surface of the transformer coupling plasma window substrate, and an air inlet hole is processed in the center of the quartz disk. A circular mounting step concentric with the air inlet hole is processed on the upper surface of the quartz disk, and the hole wall of the air inlet hole and the step surface of the mounting step are ground and polished. S3, the lower surface of the polished quartz disk is processed into an annular curved surface to serve as the lower surface of the transformer coupling plasma window substrate; S4. A spherical microstructure is formed on the lower surface of the quartz disk by chemical etching to obtain a transformer-coupled plasma window.
5. The method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to claim 4, characterized in that, Step S1 includes: S11, using a diamond wire cutter to horizontally cut high-purity semiconductor-grade quartz ingots with a diameter of 400mm~600mm into quartz discs with a thickness of 50mm~80mm; S12, the sidewall of the quartz disk is ground with a metal milling cutter to achieve a state without chipping or burrs.
6. The method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to claim 4, characterized in that, Step S2 includes: S21, the upper surface of the quartz disk is ground flat using a surface grinder to form a flat surface. The flatness of the upper surface of the ground quartz disk is <0.05mm and the roughness is 0.15μm~0.20μm. S22, the center of the upper surface of the quartz disk is milled to create a through hole with a diameter of 5mm to 8mm as the air inlet hole. S23, with the center of the through hole as the center, the upper surface of the quartz disk is milled to mill a circular recessed step with a diameter of 40mm~60mm and a depth of 20mm as the installation step; S24. Using a wool felt grinding head, and simultaneously injecting 5000~10000 grit polishing coolant, the inner wall of the through hole and the inner wall and step surface of the sunken step are ground and polished to achieve a smooth and transparent appearance.
7. The method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to claim 4, characterized in that, Step S3 includes: S31, using a spherical metal cutter, the blade moves from the stepped opening at the center of the quartz disk to the edge of the quartz disk, and the grinding feed depth is adjusted according to the preset arc contour to grind the lower surface of the quartz disk, forming an arc-shaped rough surface with a height difference, where 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, move from the stepped opening at the center of the quartz disk to the edge of the quartz disk, and adjust the grinding feed depth according to the preset arc contour to grind the arc rough surface into a finely machined annular curved surface.
8. The method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to claim 4, characterized in that, Step S4 includes: S41, the parts of the quartz disk other than the annular curved surface are shielded; S42, the annular surface is ground using 500~800 mesh silicon carbide abrasive to remove the processing texture. After grinding, the roughness of the annular surface is 1.0μm~1.3μm. S43, the quartz disk after grinding is immersed in a 10%~20% fluorine-containing acidic etching solution for 30min~60min to etch the annular curved surface into a spherical micromorphology. S44, the quartz disk is rinsed to remove the shielding, then cleaned and dried to obtain the transformer-coupled plasma window.
9. The method for fabricating a transformer-coupled plasma window for a semiconductor etching apparatus according to any one of claims 4-8, characterized in that, The total metal ion content of the quartz ingot is <500ppm, and the hydroxyl content of the quartz ingot is <50ppm.