Combined machining method for silicon carbide electrode micropores
Through the composite method of water-conducting laser roughing and mechanical finishing, the problem of micropore processing of silicon carbide electrodes is solved, and efficient and high-quality micropore processing is achieved, reducing costs and improving accuracy and stability.
Patent Information
- Application Number
- CN202510397669.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-06-24
AI Technical Summary
Due to the high hardness of the material of silicon carbide electrode micropore processing, it is difficult for the existing technology to achieve efficient and high-quality processing, resulting in high processing costs, short equipment life and difficult to meet the requirements.
Using the composite processing method, firstly, a preliminary hole is formed by rough processing by water-conducting laser, and then fine-processing is carried out on the mechanical processing equipment to form positioning holes and molding holes. Combining the advantages of both, efficient and high-quality micropore processing is achieved.
It realizes efficient and high-quality silicon carbide micropore processing, extends the service life of the drill tool, reduces processing costs, and improves processing accuracy and stability.
Smart Images
Figure CN120190504A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of semiconductor etching machine parts processing, in particular to a composite processing method for silicon carbide electrode micropores. Background Art
[0002] The inner electrode, also known as the shower head or plasma diverter, is one of the core components and consumables in the dry etcher chamber. During operation, a radio frequency electric field is applied to both ends of the electrode, and the process gas is evenly dispersed through the micropores and plasmatized, and finally reaches the wafer surface to complete the etching. The inner electrode needs to form thousands of evenly distributed micropores of equal diameter on the circular plate. The diameter of the micropores is about 0.5~1.0mm, and the micropore depth-to-diameter ratio can reach 32:1.
[0003] At present, the common materials for inner electrodes are single crystal silicon and silicon carbide. Silicon carbide is more resistant to etching by process gases such as fluorine ions than single crystal silicon, so it is more suitable as a substrate material for etched parts. However, the Mohs hardness of silicon carbide material is 9.5, second only to diamond, which brings great challenges to the micro-hole processing on silicon carbide electrodes. Figure 1 As shown, there are two main types of micro-hole processing technologies for hard and brittle materials on the market: mechanical processing and special processing. Due to the high hardness of silicon carbide materials, the life of a single drill bit used in mechanical processing is often only about 100 holes, and a single hole processing requires more than 20 minutes, which greatly increases the processing costs such as equipment and time, and it is easy to cause damage such as edge collapse and cracks during the processing. Common special processing methods include electric spark, ultrasound, etc. Each method has its own advantages and disadvantages, but it is inevitable that due to poor processing stability and other reasons, the surface quality and accuracy after processing are difficult to meet the SPEC requirements; in addition, with the change of processing depth, the energy used in feature processing will inevitably decay, and then form a processing taper, which is difficult to meet the requirements of equal-diameter micro-holes.
[0004] Therefore, high-quality processing of high-aspect-ratio microholes in high-hardness silicon carbide materials has always been one of the most difficult challenges in the industry. Summary of the invention
[0005] The present invention aims to solve the above problems and provides a composite processing method for micropores in silicon carbide electrodes, the technical solution adopted by the present invention is as follows: A composite processing method for silicon carbide electrode micropores, comprising the following steps: S1. Clean the workpiece to be processed; S2. Place the workpiece to be processed on the water-guided laser device to complete a positioning; S3. For the to-be-machined hole positions on the workpiece to be machined, conduct water-jet guided laser rough machining. The diameter of a single machined hole after machining is D2, and the diameter D2 of the single hole is smaller than the predetermined formed hole diameter D1; successively complete the water-jet guided laser rough machining of all single holes at each to-be-machined hole position on the workpiece to be machined; S4. Conduct secondary cleaning on the workpiece to be machined; S5. Place the workpiece to be machined on a machining equipment for secondary positioning; S6. Conduct primary mechanical finish machining on each single hole on the workpiece to be machined successively. A positioning hole is machined at the upper end of the single hole. The cross-section of the positioning hole is conical, and the large end of the cone opens upward; S7. For each single hole with a positioning hole formed, conduct secondary mechanical finish machining successively to form each formed hole; S8. Conduct tertiary cleaning on the machined workpiece.
[0006] On the basis of the above solution, the relationship between the diameter of the single hole after water-jet guided laser rough machining and the formed hole diameter is: D2 = 0.8 * D1.
[0007] Preferably, in step S3, the water jet pressure is 30 MPa, the laser power is 50 w, the frequency is 10 KHz, the laser scanning speed is 20 mm / s, the helium gas flow rate is 15 LPM, the machining depth is the through-hole depth H of the formed hole, and the machining shape is circular.
[0008] Preferably, in step S6, a reserved margin B is set, and the tool feed depth .
[0009] On the basis of the above solution, in step S6, a positioning drill is used for primary mechanical finish machining. The tip angle of the positioning drill is 90°, and the tool head diameter is 5 mm. During mechanical machining, the rotational speed is 10000 RPM, the single cutting depth is 0.2 mm, the feed rate is 10 mm / min, and the machining depth is the through-hole depth H of the formed hole.
[0010] Preferably, the upper end diameter of the positioning hole is larger than the formed hole diameter.
[0011] Preferably, in step S7, a PCD drill is used for secondary mechanical finish machining. The tip angle of the PCD drill is 120°, the tool head diameter is D2. During mechanical machining, the rotational speed is 15000 RPM, the single cutting depth is 0.1 mm, the feed rate is 10 mm / min, and the machining depth is the through-hole depth H of the formed hole.
[0012] Preferably, when cleaning the workpiece in steps S1, S4 and S8, the workpiece is placed flat and soaked in a cleaning solution containing dodecylbenzenesulfonate, and ultrasonic cleaning is adopted, and then rinsed with pure water.
[0013] Preferably, in step S2, the workpiece to be processed is placed flat on the water-jet guided laser workbench. After being fixed by a jig, a grating ruler and a high-precision machine tool probe are used to achieve the primary positioning of the workpiece to be processed.
[0014] Preferably, in step S5, the workpiece to be processed is placed flat on the machine tool workbench. After being fixed by a jig, a grating ruler and a high-precision machine tool probe are used to achieve the secondary positioning of the workpiece to be processed.
[0015] The beneficial effects of the present invention are as follows: By combining the respective advantages of water-jet guided laser processing and mechanical processing, high-efficiency and high-quality machining of silicon carbide micro-holes can be achieved, and the service life of the drill is greatly improved, while the processing cost is reduced. Using water-jet guided laser for the first machining process can efficiently remove the central area of the micro-hole, shortening the processing time required; reducing the cutting amount that needs to be processed by the mechanical drill bit in the subsequent process, facilitating the full cooling of the drill bit, avoiding fatigue fracture caused by insufficient cooling of the drill bit, and at the same time greatly extending the service life of the drill bit, enabling the mechanical drill bit to finish machining more than 600 micro-holes, effectively reducing the production cost; reducing the replacement frequency of the drill bit and improving the processing efficiency. By performing a single mechanical finishing process to machine a positioning hole at the end of the micro-hole, it can prevent the drill from deflecting when contacting the workpiece, effectively guiding the processing position and direction of the drill, and at the same time avoiding the breakage and chipping of the hole mouth during the subsequent drilling process through the chamfer structure at the positioning hole, improving the processing quality of the hole mouth. By performing a secondary mechanical finishing process to complete the cutting of the remaining amount, covering the processing traces of the water-jet guided laser, improving the inner wall quality, removing the processing taper and the recast layer, precisely controlling the micro-hole diameter, roundness and inner wall roughness within the requirements of SPEC, and increasing the stability and reliability of the process. Description of the Drawings
[0016] Figure 1 : Process flow chart of the prior art; Figure 2 : Process flow chart of the present invention; Figure 3 : Schematic diagram of the processing effects of multiple processes of the present invention; Figure 4 : Schematic diagram of the parameters of the single mechanical finishing process of the present invention; Figure 5 : Comparative diagram of the inner wall morphology of the micro-hole when different processing parameters are adopted in the present invention. Detailed Embodiments
[0017] The present invention will be further described below with reference to the drawings and embodiments: In the present invention, unless otherwise clearly specified or limited, the terms "installed", "connected", "connected", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0018] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "length", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "primary" and "secondary" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "primary" and "secondary" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "multiple times" is two or more times.
[0019] In the present invention, unless otherwise clearly specified or limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.
[0020] As Figure 2 and Figure 3 shown, a composite processing method for micropores of a silicon carbide electrode includes the following steps: S1. Perform a primary cleaning on the workpiece to be processed; S2. Place the workpiece to be processed on a water-guided laser device to complete a primary positioning; specifically, the workpiece to be processed is placed flat on the water-guided laser workbench, fixed by a jig, and then a primary positioning of the workpiece to be processed is realized by using a grating ruler and a high-precision machine tool probe; S3. For the to-be-machined hole positions on the workpiece to be processed, conduct water-jet guided laser rough machining. The diameter of a single hole after machining is D2, and the diameter D2 of the single hole is smaller than the predetermined formed hole diameter D1, so as to leave a machining allowance for subsequent mechanical machining. Preferably, the relationship between the diameter of the single hole after water-jet guided laser rough machining and the formed hole diameter is: D2 = 0.8 * D1, so as to ensure that the subsequent mechanical machining can cover the machining traces of the water-jet guided laser while improving efficiency and enhancing the quality of the inner wall of the formed hole. Complete the water-jet guided laser rough machining of all single holes in sequence at each to-be-machined hole position on the workpiece to be processed. The schematic cross-sectional view of the inner wall of the micro-hole after water-jet guided laser rough machining is as shown in Figure 3 -a. At this time, the quality of the hole wall of the micro-hole is poor, with obvious unevenness and a significant machining taper, and the hole diameter gradually decreases from top to bottom. Specifically, the process parameters of the water-jet guided laser rough machining are: the water jet pressure is 30 MPa, the laser power is 50 w, the frequency is 10 KHz, the laser scanning speed is 20 mm / s, the helium gas flow rate is 15 LPM, the machining depth is the through-hole depth H of the formed hole, and the machining shape is circular. S4. Conduct secondary cleaning on the workpiece to be processed. S5. Place the workpiece to be processed on the mechanical processing equipment for secondary positioning. Specifically, the workpiece to be processed is placed flat on the machine tool workbench. After being fixed by a jig, use a grating ruler and a high-precision machine tool probe to achieve secondary positioning of the workpiece to be processed. S6. Conduct primary mechanical finishing on each single hole on the workpiece to be processed in sequence. A positioning hole is machined at the upper end of the single hole. The cross-section of the positioning hole is conical, and the large end of the cone opens upward. The chamfer structure at the positioning hole avoids the breakage and chipping of the hole mouth during the subsequent drilling process and improves the machining quality of the hole mouth. The schematic cross-sectional view of the inner wall of the micro-hole after primary mechanical finishing is as shown in Figure 3 -b. A chamfer shape is machined at the upper end of the micro-hole, and the diameter of the upper end of the positioning hole is larger than the formed hole diameter, that is, the positioning hole completely covers the formed hole, so as to ensure that problems such as breakage and chipping do not occur during the machining of the formed hole. As shown in Figure 4 . During primary mechanical finishing, set a reserved margin B, and the tool feed depth . The reserved margin B is the projection of the area where the positioning hole exceeds the single hole completed by the water-jet guided laser rough machining in the horizontal plane and / or the vertical plane. Specifically, the process parameters of the primary mechanical finishing are: use a positioning drill to conduct primary mechanical finishing. The tip angle of the positioning drill is 90°, and the tool head diameter is 5 mm. During mechanical machining, the rotational speed is 10000 RPM, the single cutting depth is 0.2 mm, the feed speed is 10 mm / min, and the machining depth is the through-hole depth H of the formed hole. S7. For each single hole forming the positioning hole, secondary mechanical finish machining is carried out in sequence to form each formed hole, covering the machining traces of water-guided laser during the machining process to improve the inner wall quality; the schematic cross-sectional view of the inner wall of the micro-hole after secondary mechanical finish machining is as shown in Figure 3 -c. The inner surface of the formed hole is flat and has a consistent diameter; Specifically, the process parameters of the secondary mechanical finish machining are as follows: The secondary mechanical finish machining is carried out using a PCD drill bit. The tip angle of the PCD drill bit is 120°, the diameter of the tool head is D2, the rotational speed during mechanical machining is 15000 RPM, the single cutting depth is 0.1 mm, the feed rate is 10 mm / min, and the machining depth is the through-hole depth H of the formed hole; S8. The machined workpiece is cleaned three times.
[0021] When cleaning the workpiece in step S1, step S4 and step S8, the workpiece is placed flat and soaked in a cleaning solution containing dodecylbenzenesulfonate, and ultrasonic cleaning is used, and then rinsed with pure water to remove the oil and particles on the surface of the workpiece.
[0022] As shown in Figure 5 , for different machining parameters, the inner wall morphology of the micro-hole varies greatly: Condition A: When machining the micro-hole using a single water-guided laser, obvious longitudinal grooves appear on the inner wall of the micro-hole; Condition B: When machining the micro-hole by mechanical machining method, with the drill bit rotational speed of 10000 RPM, the single cutting depth of 0.1 mm, and the feed rate of 10 mm / min, there are problems such as poor chip evacuation and overheating of the tool during the machining process, and there is a broken layer on the inner wall of the machined micro-hole; Condition C: Using the machining method and process parameters of this embodiment, the inner wall of the micro-hole is flat and smooth, and the machining quality is high; Condition D: When machining the micro-hole by mechanical machining method, with the drill bit rotational speed of 10000 RPM, the single cutting depth of 0.3 mm, and the feed rate of 10 mm / min, there are problems such as tool vibration and insufficient tool rigidity during the machining process, and there is an obvious broken layer on the inner wall of the machined micro-hole; Condition E: When machining the micro-hole by mechanical machining method, with the drill bit rotational speed of 10000 RPM, the single cutting depth of 0.2 mm, and the feed rate of 5 mm / min, there is an obvious problem of poor chip evacuation during the machining process, and there are cracks on the inner wall of the micro-hole with the same width as the chip evacuation groove of the tool; Condition F: When machining the micro-hole by mechanical machining method, with the drill bit rotational speed of 10000 RPM, the single cutting depth of 0.2 mm, and the feed rate of 20 mm / min, there are problems such as insufficient tool rigidity and difficulty in meeting the cutting requirements during the machining process, and the tool is worn; Working condition G: No positioning hole is machined at the end of the micro-hole, and there is broken edge at the hole opening, resulting in poor machining quality. Working condition H: A positioning hole is machined at the end of the micro-hole, and the hole opening has a flat shape, high roundness, and high machining quality at the hole opening.
[0023] The present invention has been described by way of example above, but the present invention is not limited to the above specific embodiments, and any modification or variation based on the present invention falls within the scope of protection required by the present invention.
Claims
1. A composite processing method for micropores in silicon carbide electrodes, characterized in that: The following steps are involved: S1. Clean the workpiece to be processed; S2. Place the workpiece to be processed on the water-guided laser device to complete a positioning; S3. Performing water-conducting laser rough machining on the hole positions to be machined on the workpiece to be machined, wherein the diameter of the single hole after machining is D2, and the single hole diameter D2 is smaller than the predetermined forming hole diameter D1; completing water-conducting laser rough machining of all single holes at each hole position to be machined on the workpiece to be machined in sequence; S4. Perform secondary cleaning on the workpiece to be processed; S5. Place the workpiece to be processed on the machining equipment for secondary positioning; S6. Each single hole on the workpiece to be processed is subjected to mechanical finishing in sequence, and a positioning hole is formed at the upper end of the single hole, wherein the positioning hole has a conical cross section and the large end of the cone opens upward; S7. For each single hole forming the positioning hole, secondary mechanical finishing is performed in sequence to form each forming hole; S8. Clean the processed workpiece three times.
2. A composite processing method for micropores in silicon carbide electrodes according to claim 1, characterized in that: The relationship between the single hole diameter completed by water-guided laser rough machining and the formed hole diameter is: D2=0.8*D1.
3. A composite processing method for silicon carbide electrode micropores according to claim 1, characterized in that: In step S3, the water jet pressure is 30 MPa, the laser power is 50 W, the frequency is 10 KHz, the laser scanning speed is 20 mm / s, the helium flow rate is 15 LPM, the processing depth is the forming hole through-hole depth H, and the processing shape is a circle.
4. A composite processing method for silicon carbide electrode micropores according to claim 1, characterized in that: In step S6, set the reserve margin B and the tool feed depth .
5. A composite processing method for micropores in silicon carbide electrodes according to claim 4, characterized in that: In step S6, a positioning drill is used for mechanical finishing, wherein the positioning drill has a tip angle of 90° and a head diameter of 5mm, the machining speed is 10000RPM, the single cutting amount is 0.2mm, the feed speed is 10mm / min, and the machining depth is the through-hole depth H of the formed hole.
6. A composite processing method for micropores in silicon carbide electrodes according to claim 1, characterized in that: The diameter of the upper end of the positioning hole is larger than the diameter of the forming hole.
7. A composite processing method for micropores in silicon carbide electrodes according to claim 1, characterized in that: In step S7, a PCD drill is used for secondary mechanical finishing. The PCD drill has a tip angle of 120° and a head diameter of D2. The rotation speed during machining is 15000 RPM, the single cutting amount is 0.1 mm, the feed speed is 10 mm / min, and the machining depth is the through-hole depth H of the formed hole.
8. The composite processing method for silicon carbide electrode micropores according to claim 1, characterized in that: When the workpiece is cleaned in step S1, step S4 and step S8, the workpiece is placed flat and immersed in a cleaning solution containing dodecylbenzene sulfonate, and is cleaned by ultrasonic wave, and then rinsed with pure water.
9. A composite processing method for micropores in silicon carbide electrodes according to claim 1, characterized in that: In step S2, the workpiece to be processed is placed flat on the water-guided laser workbench, fixed by a fixture, and then the workpiece to be processed is positioned once using a grating ruler and a high-precision machine tool probe.
10. A composite processing method for micropores in silicon carbide electrodes according to claim 1, characterized in that: In step S5, the workpiece to be processed is placed flat on the machine tool workbench, fixed by a fixture, and then a grating ruler and a high-precision machine tool probe are used to achieve secondary positioning of the workpiece to be processed.