Surface treatment method for covering ring in thin film deposition

Abstract

The invention discloses a surface treatment method for a covering ring in thin film deposition. The surface treatment method comprises the steps that a multi-abrasive-particle ruling tool, a clamping assembly and a covering ring fixing chuck are designed; a uniform scratch structure of the target surface roughness is realized by setting a scribing processing path and mechanical parameters; according to mechanical parameter setting, the axial feeding amount is specifically adjusted, the set displacement amount is converted into elastic potential energy of a spring, and therefore quantitative and controllable loads are applied to press a tool bit and the surface of a covering ring; the scribing processing path setting specifically sets the rotation angle of the multi-abrasive-particle scribing tool according to the structural characteristics of multi-abrasive-particle arrangement of the multi-abrasive-particle scribing tool, the abrasive particle spacing, the rotation angle and the scratch coverage rate, and the rotation angle is an acute angle. According to the method, wide-range control over the surface roughness of the covering ring can be achieved, surface pollution and damage are effectively reduced, the adhesive force and surface integrity of a film on the surface of the covering ring are improved, and therefore the service life of the film is effectively prolonged, the cavity opening cleaning frequency is reduced, and the stability and production efficiency of the film deposition process are improved.

Description

Technical Field

[0001] The invention relates to the technical field of precision machining and surface treatment, and in particular to a surface treatment method for a cover ring in thin film deposition. Background Art

[0002] The cover ring is a key component of thin film deposition process equipment in semiconductor processes such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). Its surface roughness, morphology, surface defects and contamination are directly related to the quality of thin film deposition and process stability. In process chambers such as CVD and ALD, the precursor gas not only deposits thin films on the wafer, but also inevitably forms a covering layer on the surface of the cover ring. Once the surface roughness of the cover ring is too high or too low, the morphology is irregular, and there are residual debris on the surface, cracks or shedding may occur during the film deposition process. If the broken film fragments fall onto the wafer surface, it may cause wafer damage, which in turn causes process defects and affects the stability and production efficiency of the overall process. Therefore, optimizing the surface processing method of the cover ring and accurately controlling its surface roughness and surface quality can effectively improve the adhesion of the film, prolong the integrity of the film layer, and reduce the frequency of open cavity cleaning, thereby significantly improving the yield and production capacity of the thin film deposition process.

[0003] Sandblasting is a traditional method for surface treatment of cover rings, but there are still many limitations. First, due to the influence of multiple factors such as sand particle shape, spray angle, sandblasting pressure and time, it is difficult to achieve precise roughness control in sandblasting, and the surface usually has large roughness fluctuations, which will lead to uneven film deposition. Secondly, tiny sand particles may remain on the surface during the sandblasting process. These residues will become a source of contamination in the subsequent deposition process and affect the deposition quality of the film. In addition, sandblasting depends on multiple variables, which makes it easy to produce uneven micromorphology during the surface treatment process, thereby affecting the uniformity of gas flow and reaction, and further affecting the quality of thin film deposition. Finally, for cover rings with complex shapes or large areas, the uniformity of sandblasting is also easily affected by the surface shape and processing environment, resulting in uneven treatment in certain areas, affecting the overall treatment effect.

[0004] In summary, traditional sandblasting cannot meet the requirements of modern thin film deposition processes for cover rings. It is urgent to develop a new cover ring surface treatment method to accurately control roughness, reduce contamination and improve uniformity to meet the high quality requirements of thin film deposition. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a surface treatment method for a cover ring in thin film deposition, which can achieve wide-range precise control of roughness (4-5 μm), effectively reduce surface stress concentration, and reduce microscopic damage, thereby significantly improving the mechanical bonding force between the film and the cover ring surface, and improving the stability and production efficiency of the thin film deposition process. In order to achieve the above-mentioned purpose and other advantages according to the present invention, a surface treatment method for a cover ring in thin film deposition is provided, comprising:

[0006] Design of multi-abrasive scoring tools, clamping assemblies and cover ring fixed chucks;

[0007] The target surface roughness can be uniformly controlled by setting the scratching process path and mechanical parameters;

[0008] The mechanical parameter setting specifically adjusts the axial feed amount, converts the set displacement amount into the elastic potential energy of the spring, thereby applying a quantitative and controllable load to press the cutter head and the cover ring surface;

[0009] The scratching processing path setting is specifically to set the rotation angle of the multi-abrasive scratching tool through the structural characteristics of the multi-abrasive arrangement of the multi-abrasive scratching tool, the abrasive spacing, the rotation angle and the scratch coverage, and the rotation angle is an acute angle.

[0010] The multi-abrasive tool scoring processing method adopted by the present invention has significant advantages. A uniform microscopic scratch structure is gradually formed on the surface of the cover ring by using the controllable design of the abrasive arrangement and the rotation angle, thereby achieving precise control of the surface roughness of the cover ring, making it stable within the range of 4 to 5 μm. In addition, less debris is generated and it is easy to clean, reducing the risk of surface contamination, and solving the problem that traditional methods such as sandblasting cannot accurately control the roughness of the processed surface, and that sand particles usually remain on the surface after sandblasting, making it difficult to clean thoroughly.

[0011] Multi-abrasive tool engraving can form uniform micro scratches over a large area, and the tool life is long, and the cost of consumables and equipment maintenance is low, which solves the problem that traditional laser processing is difficult to achieve large-area surface texture processing and the processing cost is high.

[0012] In terms of processing efficiency, the multi-abrasive arrangement improves the removal efficiency and shortens the processing time while ensuring the stability of the roughness. Finally, due to the improvement of the film adhesion performance and the extension of the film layer integrity, the present invention effectively reduces the frequency of cavity cleaning, thereby significantly improving the production efficiency of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structure of a multi-abrasive scribing tool for a surface treatment method of a cover ring in thin film deposition according to the present invention;

[0014] Figure 2 It is a schematic structural diagram of the change of the abrasive grain spacing after the multi-abrasive grain scribing tool used in the surface treatment method of the cover ring in thin film deposition according to the present invention is rotated;

[0015] Figure 3 It is a schematic diagram of the structure of a clamping assembly used in the surface treatment method of a cover ring in thin film deposition according to the present invention;

[0016] Figure 4 It is a schematic diagram of the assembly structure of the cover ring and the chuck according to the surface treatment method of the cover ring in thin film deposition of the present invention;

[0017] Figure 5 It is a schematic diagram of the assembly structure of a chuck and a rotating platform for the surface treatment method of a cover ring in thin film deposition according to the present invention;

[0018] Figure 6 It is a schematic diagram of the overall processing structure of the surface treatment method for a cover ring in thin film deposition according to the present invention.

[0019] In the figure: 1—covering ring; 2—tool head; 3—abrasive; 4—multi-abrasive scoring tool; 5—spring sleeve; 6—sleeve; 7—spring; 8—bolt; 9—slideway; 10—through hole; 11—tool handle; 12—hole on the tool handle; 13—covering ring fixing chuck; 14—circular ring groove; 15—threaded hole; 16—screw; 17—rotating worktable; 18—turntable; 19—flat key; 20—keyway; 21—machining platform; 22—clamp; 23—horizontal slideway; 24—vertical slideway; L—tool head length; b—tool head width; D—distance between adjacent abrasives; D*—controllable distance between abrasives. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Reference Figure 1 , a surface treatment method for a cover ring in thin film deposition, comprising:

[0022] Design a multi-abrasive scoring tool 4, a clamping assembly and a cover ring to fix the chuck 13;

[0023] The target surface roughness can be uniformly controlled by setting the scratching process path and mechanical parameters;

[0024] The mechanical parameter setting specifically adjusts the axial feed amount, converts the set displacement into the elastic potential energy of the spring, and thus applies a quantitative and controllable load to press the cutter head and the cover ring surface; in terms of theoretical research, according to the target roughness (4-5 μm), the processing parameters are calculated: surface roughness R a The relationship between the scratch depth h and the scratch spacing p can be approximately expressed as:

[0025]

[0026] According to the formula, the scratch shape can be approximated as a V shape, the angle of the abrasive is θ = 60°, and the relationship between the scratch width w and depth h is

[0027] w=2·h·tan(θ / 2)

[0028] Substituting the width w into the roughness formula, we can get the deformation formula of roughness:

[0029]

[0030] When the scratch spacing is between 300 and 400 μm, the scratch depth corresponds to a range of 50 to 100 μm, and the roughness R a The range is consistent with the target roughness range (4-5μm).

[0031] The scratching processing path setting is specifically to set the rotation angle of the multi-abrasive scratching tool through the structural characteristics of the multi-abrasive arrangement of the multi-abrasive scratching tool, the abrasive spacing, the rotation angle and the scratch coverage, and the rotation angle is an acute angle. In terms of path design, based on the structural characteristics of the multi-abrasive arrangement of the tool, the abrasive spacing, the rotation angle and the scratch coverage are comprehensively considered, and the tool is rotated by a certain angle so that the abrasive along the processing direction falls between the two abrasives in the vertical processing direction, so that the rotation angle can be reasonably adjusted to achieve the control of the abrasive spacing, so that the abrasive spacing can be controlled, ensuring that the final surface roughness is stable within the target range. The specific rotation angle is calculated as follows:

[0032] According to the above calculation, the scratch spacing of the target roughness ranges from 300 to 400 μm, and the distance between adjacent abrasive particles is 1.2 mm. Here, the rotation angle is

[0033]

[0034] Conclusion

[0035] In terms of machining parameter setting, by adjusting the axial feed amount, the set displacement is converted into the elastic potential energy of the spring, thereby applying a quantitative and controllable load to press the cutter head and the cover ring surface to avoid machining defects caused by insufficient or overload. According to the abrasive arrangement and the scratch depth requirements that meet the target roughness, the load that needs to be applied to a single abrasive is first calculated:

[0036] The applied load F is related to the scratch depth h, the material contact shape factor k, the yield strength σ of the cover ring material, and the scratch contact area A. First, assume that the tool is a pointed cone and the abrasive tip angle θ = 60°:

[0037] A=π·r 2

[0038]

[0039] So A=9.42·h 2 The material contact shape factor k is related to the tool angle and scratch mode, usually k≈3. The yield strength σ of the cover ring material is about 300-400 MPa, so the load F required to be applied by a single abrasive particle can be calculated. s

[0040] F s = k·σ·A

[0041] When the scratch depth of a single abrasive particle is about 50-100 μm, the load required to be applied by a single abrasive particle is calculated to be 0.2-1.1 N. The total number of abrasive particles N t = 120, then the total load F of the cutter head on the cover ring can be calculated

[0042] F=N t ·F s

[0043] The total load applied by the cutter head to the cover ring is calculated to be 25.44 to 135.72N.

[0044] In actual operation, this design uses a force in the range of 80 to 100N to avoid damage to the tool or cover ring caused by excessive pressure. By pressing the tool against the surface of the cover ring, rotating the worktable and driving the chuck and cover ring to rotate at a speed of 10rpm / min, the abrasive grains on the tool head can evenly scratch the surface of the cover ring. Since the relative position of the cover ring and the tool is fixed, the position of the scratches produced by the abrasive grains during the rotation of the cover ring is also fixed, thus avoiding the phenomenon that the tool and the cover ring are in rigid contact under normal processing conditions, which is prone to crushing or even damaging the machine tool spindle. During the processing, the spring sleeve enables each abrasive grain to continuously scratch the corresponding scratches with a certain pressure during the rotation of the cover ring, so that the scratch depth gradually deepens until the corresponding target roughness is reached, and finally forms a microscopic scratch structure that meets the target roughness requirements. Since there is a height difference of about ±3μm between the abrasive particles during the welding process, it may not be possible for all the abrasive particles to participate in the scratching in the initial processing. However, the spring sleeve allows the cutter head to always press on the surface of the cover ring for scratching with a certain pressure. Therefore, as the scratch depth gradually deepens, the abrasive particles at a lower position can also produce a certain depth of scratches on the cover ring, which effectively enables all the abrasive particles to participate in the scratching. In addition, the target roughness requires a scratch spacing of 300 to 400μm, and the scratch depth is also 50 to 100μm. Therefore, when scratching gradually, the scratch depth gradually increases. Although there is a height difference of ±3μm, it does not affect the generation of scratch depth and the impact on roughness. Therefore, through scientific path planning and parameter design, the efficiency and consistency of the processing process are ensured, which provides important support for improving process stability and processing quality.

[0045] like Figure 1-2As shown, the multi-abrasive scoring tool 4 includes a tool handle 11, a tool head 2 fixed to the tool handle 11, and a plurality of abrasive grains 3 fixed on the tool head 2, and the geometric shape of the abrasive grains 3 is a polyhedral pyramid, and the angle of the vertex of the abrasive grains 3 is an acute angle. A plurality of parallel and spaced abrasive grains 3 are arranged on the top surface of the tool head 2, and the spacing between the abrasive grains 3 and the distance between each row are 1.2 mm. The design of the multi-abrasive tool achieves high-precision and high-consistency scoring processing performance by optimizing the material selection, geometric shape, arrangement method and height control of the abrasive grains. First, natural diamond abrasive grains with a diameter of 1 mm are selected because of their high hardness and excellent wear resistance to meet strict processing requirements. At the same time, the selected abrasive grains have a polyhedral pyramid geometry with a vertex angle close to 60° to optimize the cutting performance and ensure the uniformity of the material removal process and the consistency of the surface scratches. In terms of abrasive grain arrangement, the tool adopts a four-row parallel arrangement structure, each row contains 30 abrasive grains, and the abrasive grain spacing and each row interval are 1.2mm. This design not only covers the width of the cover ring, but also significantly improves the uniformity and coverage of surface scratches. In order to further improve the processing accuracy, the abrasive grain height tolerance is strictly controlled within ±3μm, the tool base is initially adjusted through high-precision surface grinding technology, and repeatedly calibrated with the help of high-precision measuring equipment such as laser interferometers to ensure that each abrasive grain can evenly contact the surface of the cover ring.

[0046] Furthermore, in order to fully cover the cover ring 1 during processing, the length L of the tool head 2 is 34 mm, the width b is 8 mm, and the particle size of the abrasive grains 3 is 1 mm. Considering the requirements of the target roughness for the scratch spacing d during processing, the abrasive grain spacing D is set to 1.2 mm, and the abrasive grain arrangement method of four rows of abrasive grains aligned front and back is adopted. Figure 2 As shown, for the convenience of introducing this design, the direction along the processing direction is set as the Y direction, and the direction perpendicular to the processing direction is set as the X direction. According to the calculation of the target roughness, the scratch spacing range is between 300 and 400 μm. The distance between the tips of adjacent abrasives on the tool, such as abrasives m1 and m5, and abrasives m1 and m2, is a fixed 1.2 mm. However, when we rotate the tool by a certain angle, the scratches of the four abrasives in each column, such as m1, m2, m3 and m4, will no longer overlap, but each abrasive will separately carve a scratch in the Y direction. In order to make the scratch spacing fit the above calculated range, the rotation angle is calculated so that the projection of the tips of abrasives m2, m3 and m4 in the X direction can fall between two adjacent abrasives.

[0047] like Figure 3 As shown, the clamping assembly includes a sleeve 6 sleeved on the handle 11 and a spring 7 placed in the sleeve 6;

[0048] The sleeve 6 includes a straight rod section and a spring sleeve 5 integrally connected to the straight rod section. The surface of the spring sleeve 5 is provided with two symmetrically arranged long strip-shaped slots 9, and the handle 11 is provided with two through holes, which correspond to the long strip-shaped slots 9. A long strip-shaped slot 9 with a width of 5 mm is provided at a position 7.5 mm from the bottom edge of the sleeve 6. The assembly of the bolt 8 can prevent the tool 4 from falling downward and limit its rotation around the z-axis. The inside of the sleeve 6 is a hole 10 with a diameter of 12 mm and a depth of 60 mm, which can be placed in a spring 7 with a diameter of 12 mm and a height of 20 mm. Considering the consumption of the spring 7 during the processing, it is designed as a replaceable standard part to reduce the processing cost. The design uses a spring that can generate a pressure of 40N when compressed by 1 mm. The handle 11 has a diameter of 12 mm and a length of 48 mm. There are two holes 12 with a diameter of 5 mm on the tool 4, and the diameter of the bolt 8 is 5 mm. The assembly method is to first put the spring 7 into the internal hole 10 of the sleeve, then insert the tool handle 11 of the tool into the hole 10, and then fix the tool 4 and the sleeve 6 with bolts 7. At this time, the five degrees of freedom of the tool 4 are restricted. After the assembly is completed, there will be 8mm of the tool handle 11 that has not entered the hole of the sleeve. During the processing, it can slide upward through the bolts 8 and the slide groove 9 on the sleeve to buffer the pressure on the tool and the covering ring. The design of the clamping assembly focuses on ensuring the position stability and load controllability of the tool and the covering ring during the processing, thereby improving the processing accuracy and consistency. The tool is fixed in the sleeve by bolts, and the top of the sleeve is in contact with the spring. This structure limits the five degrees of freedom of the tool and only allows it to produce controllable displacement in the vertical direction. The displacement is converted into the elastic potential energy of the spring, thereby providing a stable and adjustable axial load for the tool, ensuring that the tool is always tightly pressed on the surface of the covering ring. In terms of clamping the covering ring, a special chuck device is manufactured using 3D printing technology according to the size and shape of the covering ring, and the chuck is firmly fixed on the rotating workbench by screws. This design effectively avoids the cover ring from deflecting or vibrating during the rotation and scratching process, ensuring the accuracy of the processing path and the uniformity of the scratches. The above clamping system achieves high-precision control of the relative position between the tool and the cover ring through precise design and strict calibration, providing reliable mechanical support for the scratching process of multi-abrasive tools.

[0049] like Figure 4As shown, the cover ring fixing chuck 13 is provided with an annular groove 14, in which the cover ring 1 is embedded, and the cover ring 1 protrudes from the surface of the cover ring fixing chuck 13. The outer diameter of the cover ring 1 is 400mm, and the inner diameter is 342mm. After the cover ring 1 is modeled, a model of the chuck 13 matching it is constructed according to the shape of the cover ring, and its diameter is 430mm, which is completed by 3D printing. During the processing, the chuck 13 drives the cover ring 1 to rotate with the turntable on the rotating platform, maintaining no relative sliding with the cover ring 1, and ensuring that when the tool 4 applies a certain pressure on the cover ring for engraving, there will be no oscillation and slippage, so that each abrasive can continue to engrave the corresponding scratches during the rotation process without deviation. Considering the positional relationship between the tool 4, the cover ring 1 and the chuck 13 during processing, the design requires that after the cover ring 1 and the chuck 13 are assembled, the surface of the cover ring 1 should exceed the surface of the chuck 13 by 1mm to prevent the abrasive particles of the tool 4 from damaging and scratching other parts of the chuck 13 during processing, thereby affecting the life of the tool and the chuck. At the same time, in order to better handle the inclined surface on the inner side of the cover ring, a circular groove 14 with a depth of 15mm and a width of 26mm is designed in the area close to the inner side of the circular cover ring on the chuck 13 to avoid interference with the chuck 13 when adjusting the tool 4 to scratch the inclined surface on the inner side of the cover ring. Figure 5 As shown, there are four threaded holes 15 with a diameter of 10 mm on the chuck 13, which are connected to the turntable 18 on the rotating worktable 17 through screws 16. In order to prevent the chuck 13 and the turntable 18 from sliding relative to each other during the processing, four flat keys 19 with a length of 150 mm, a height of 10 mm, and a width of 30 mm are set at the bottom of the chuck 13, and corresponding keyways 20 are set on the turntable, which are fixed with screws 16 to finally form a relatively stable connection.

[0050] like Figure 6 As shown, first, the chuck 13 and the turntable 18 are fixed on the processing platform 21 by screws 16 and keys, then the covering ring 1 is placed in the chuck 13, and then the tool 4 and the sleeve 6 are assembled. After the assembly is completed, the connecting rod of the spring sleeve 5 is fixed to the fixture 22 on the processing platform, and the slide rail 23 on the processing platform is adjusted to adjust the tool to a position that can completely cover the covering ring. Then, the tool is rotated by a certain angle to adjust the scratch spacing, and then the slide rail 24 on the processing platform is adjusted to move the tool downward to the position where it connects with the surface of the covering ring, and then it continues to press down 2mm. At this time, the pressure applied by the abrasive particles on the tool to the covering ring is 80N. Finally, the rotation speed is adjusted to start the rotating platform to make the covering ring rotate and scratch, thereby gradually forming a large area of ​​micro texture on the surface of the covering ring, thereby achieving the target roughness.

[0051] The number of devices and processing scales described here are used to simplify the description of the present invention, and the application, modification and variation of the present invention will be obvious to those skilled in the art.

[0052] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A surface treatment method for a cover ring in thin film deposition, characterized in that: include: Designing a multi-abrasive scoring tool (4), a clamping assembly and a cover ring fixing chuck (13); The target surface roughness can be uniformly controlled by setting the scratching process path and mechanical parameters; The mechanical parameter setting specifically adjusts the axial feed amount, converts the set displacement amount into the elastic potential energy of the spring, thereby applying a quantitative and controllable load to press the cutter head and the cover ring surface; The scratching processing path setting is specifically to set the rotation angle of the multi-abrasive scratching tool through the structural characteristics of the multi-abrasive arrangement of the multi-abrasive scratching tool, the abrasive spacing, the rotation angle and the scratch coverage, and the rotation angle is an acute angle.

2. A surface treatment method for a cover ring in thin film deposition as claimed in claim 1, characterized in that: The quantitatively controllable load ranges from 25.44 to 135.72N.

3. A surface treatment method for a cover ring in thin film deposition as claimed in claim 1, characterized in that: The multi-abrasive grain scoring tool (4) comprises a tool handle (11), a tool head (2) fixed to the tool handle (11), and a plurality of abrasive grains (3) fixed to the tool head (2), wherein the geometric shape of the abrasive grains (3) is a polyhedral pyramid, and the vertex angle of the abrasive grains (3) is an acute angle.

4. A surface treatment method for a cover ring in thin film deposition as claimed in claim 3, characterized in that: A plurality of parallel and spaced abrasive grains (3) are arranged on the top surface of the cutter head (2), and the spacing between the abrasive grains (3) and the distance between each row are both 1.2 mm.

5. A surface treatment method for a cover ring in thin film deposition as claimed in claim 3, characterized in that: The clamping assembly comprises a sleeve (6) sleeved on the knife handle (11) and a spring (7) placed in the sleeve (6); The sleeve (6) comprises a straight rod section and a spring sleeve (5) integrally connected to the straight rod section, two symmetrically arranged long strip-shaped sliding grooves (9) are provided on the surface of the spring sleeve (5), and two through holes are provided on the handle (11), and the through holes correspond to the long strip-shaped sliding grooves (9).

6. A surface treatment method for a cover ring in thin film deposition as claimed in claim 1, characterized in that: The covering ring fixing chuck (13) is provided with an annular groove (14), a covering ring (1) is embedded in the annular groove (14), and the covering ring (1) protrudes from the surface of the covering ring fixing chuck (13).

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