Wafer tilt detection method and wafer tilt detection apparatus

Abstract

This invention discloses a wafer tilt detection method and a wafer tilt detection device for detecting the state of a wafer on a plating head. The wafer tilt detection method includes the following steps: S10, constructing a detection area enclosed by at least three detection mechanisms, and constructing the coverage area of ​​the detection area to be larger than the area of ​​the wafer; S20, setting the object detected by the detection mechanism as the surface of the wafer to be adsorbed by the plating head; S30, before the plating head clamps the wafer and closes the clamping action, opening the detection mechanism and determining whether the outer edge of the wafer extends out of the detection area; when the wafer is within the detection area, closing the plating head and clamping the wafer; when the outer edge of the wafer extends out of the detection area, the detection mechanism triggers a signal to stop the plating head from closing the clamping action of the wafer and correspondingly stops closing the clamping action of the wafer.

Description

Technical Field

[0001] This invention relates to a method and apparatus for detecting wafer skewness. Background Technology

[0002] In the semiconductor manufacturing process, during the loading and unloading of wafers via a head, the wafer may not be placed flat for various reasons, resulting in a "skewed" phenomenon. If the head performs a closing / clamping action while the wafer is in a skewed state, it will directly lead to wafer damage.

[0003] Currently, the market urgently needs an effective wafer tilt detection mechanism. However, traditional detection mechanisms typically use optical sensors (such as photoelectric, fiber optic, laser displacement, and vision sensors) to detect the wafer surface. Whether directly measuring distance or through image analysis, these mechanisms are heavily reliant on the reflective properties of the wafer surface. However, the surface conditions of wafers in actual production are complex. Wafers require cleaning during loading and unloading, which may result in water droplets of varying thicknesses. Additionally, there are specular reflections and brightness differences caused by uneven patterns and materials. These issues severely interfere with the light propagation path and echo signals, leading to false alarms or detection failures in determining whether a wafer is in a tilted state, thus preventing reliable detection of wafer tilt. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of poor detection accuracy and high false judgment rate of the detection device in the prior art when it is in the "skewed" state, and to provide a wafer skew detection method and wafer skew detection device.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] A method for detecting wafer tilt, the method being used to detect the state of a wafer on a plating head, the method comprising the following steps:

[0007] S10. Construct a detection area enclosed by at least three detection institutions, and construct the coverage area of ​​the detection area to be larger than the area of ​​the wafer;

[0008] S20. The object detected by the detection mechanism is set as the surface of the wafer for the plating head to adsorb the wafer.

[0009] S30. Before the plating head clamps the wafer and closes the clamping action, the detection mechanism is turned on and it is determined whether the outer edge of the wafer extends out of the detection area. When the wafer is within the detection area, the plating head is closed and the wafer is clamped. When the outer edge of the wafer extends out of the detection area, the detection mechanism triggers a signal to stop the plating head from closing the clamping action of the wafer and stops the clamping action of the wafer accordingly.

[0010] In this solution, multiple detection mechanisms are set above the plating head to construct a detection area larger than the wafer. The detection target is set on the plating head, which has uniform material and surface brightness and is free of water droplets during operation, to adsorb the surface of the wafer. This completely eliminates the problem of inaccurate detection of whether the wafer is in a "skewed" state due to interference factors such as patterns, water droplets, and reflections when the detection mechanism directly detects the wafer surface. The detection stability is greatly improved and false judgments are reduced, effectively avoiding wafer damage, reducing production losses, improving yield and equipment safety. It does not depend on any characteristics of the wafer itself (type, surface film, polishing degree, etc.), and achieves universal compatibility with all known wafer types and manual / automatic plating head equipment. It is also compatible with various specifications and types of wafers. The optical path of the detection mechanism can be adjusted, which greatly improves the applicability and practicality of the detection technology.

[0011] Preferably, step S10 further includes the following step:

[0012] The detection end of the detection mechanism is directed vertically or tilted toward the plating head to adsorb the surface of the wafer.

[0013] In this scheme, the above settings enable the light beam emitted from the detection end to be effectively transmitted to the surface of the plating head used to adsorb the wafer.

[0014] Preferably, step S10 further includes the following step:

[0015] At least three of the aforementioned detection mechanisms are spaced apart and evenly distributed above the wafer.

[0016] In this solution, the above settings effectively create a detection area that provides full coverage of the outer edge of the wafer.

[0017] Preferably, step S30 further includes the following step:

[0018] When the detection mechanism is turned on, the light beam emitted by the detection mechanism is used for distance measurement. When the distance between the light beam emitted by the detection mechanism and the object being detected by the detection mechanism is lower than a preset value, it is determined that the outer edge of the wafer extends beyond the detection area.

[0019] In this solution, the detection target is set to the surface of the plating head, rather than the surface of the wafer, and the judgment is made by distance measurement. This overcomes the problem of inaccurate detection of whether the wafer is in a "skewed" state due to interference factors such as patterns, water droplets, and reflections.

[0020] Preferably, step S10 further includes the following step:

[0021] When constructing the detection area, the difference between the coverage area of ​​the detection area and the outer edge of the wafer is set to 0-2mm.

[0022] In this solution, the detection accuracy is improved by limiting the difference between the detection area and the outer edge of the wafer through the above settings.

[0023] A wafer tilt detection device, wherein the wafer tilt detection device uses the wafer tilt detection method described above to detect the state of the wafer being located inside the plating head, the wafer tilt detection device comprising:

[0024] A support is provided above the wafer that the plating head is used to adsorb; the support is provided with multiple mounting plates.

[0025] The detection mechanism includes at least three detection mechanisms, which are detachably connected to the mounting plate and electrically connected to the plating head. The detection ends of the at least three detection mechanisms are perpendicular or inclined toward the surface of the wafer to be adsorbed by the plating head and enclose a detection area larger than the wafer. When the wafer is located within the detection area, the plating head performs a closing clamping action on the wafer. When the outer edge of the wafer extends beyond the detection area, the detection mechanism sends a signal to stop the plating head from closing the clamping action on the wafer.

[0026] In this solution, a bracket and mounting plate are set above the plating head to support multiple inspection mechanisms. These mechanisms are then used to construct an inspection area larger than the wafer. The inspection target is placed on the plating head, which has a uniform material and surface brightness and is free of water droplets during operation. This method completely eliminates the problem of inaccurate detection of whether the wafer is in a "skewed" state due to interference factors such as patterns, water droplets, and reflections that cause direct inspection of the wafer surface by the inspection mechanism. The inspection stability is greatly improved and false judgments are reduced. This effectively avoids wafer damage caused by the plating head closing the wafer clamping action due to false judgments, thereby reducing production losses, improving yield, and enhancing equipment safety.

[0027] Preferably, at least three of the detection mechanisms are spaced apart from each other in the circumferential direction of the support, and the central angles corresponding to the regions between two adjacent detection mechanisms are the same.

[0028] In this solution, the above settings effectively create a detection area that provides full coverage of the outer edge of the wafer.

[0029] Preferably, a plurality of mounting holes are provided at intervals on the mounting plate along the radial direction of the bracket, and the detection mechanism is connected to the mounting plate through the mounting holes.

[0030] In this solution, the above-mentioned settings allow the position of the detection mechanism along the radial direction of the support to be adjusted, thereby allowing the range of the detection area to be adjusted for detecting whether wafers of different sizes are tilted.

[0031] Preferably, the detection area is located on the same surface of the wafer used by the plating head to adsorb the wafer;

[0032] And / or, the detection area includes at least one detection end of the detection mechanism that is perpendicular or inclined toward the plating head and is different from the surface of the plating head used to adsorb the wafer.

[0033] In this scheme, the above-described configuration allows the detection area to be formed by the beams emitted by the three detection mechanisms being located on the same plane, i.e., the surface on which the plating head adsorbs the wafer. Of course, the beams emitted by the three detection mechanisms in the detection area can also be located on different planes. For example, the beams emitted by two detection mechanisms can be located on the surface on which the plating head adsorbs the wafer, while the beam emitted by one detection mechanism can be located above or below the surface on which the plating head adsorbs the wafer, thus forming an effective detection area.

[0034] Preferably, the detection mechanism is a laser displacement sensor.

[0035] In this solution, the distance measurement function of the laser displacement sensor is used to measure distance by means of the above settings. The distance measurement value is changed by judging whether the wafer extends out of the detection area and blocks the light path of the beam, thereby improving the detection accuracy.

[0036] The positive and progressive effects of this invention are as follows: By setting multiple detection mechanisms above the plating head, a detection area larger than the wafer is constructed. The detection target is set on the plating head, which has uniform material, consistent surface brightness, and is free of water droplets during operation, to adsorb the surface of the wafer. This completely eliminates the problem of inaccurate detection of whether the wafer is in a "skewed" state due to interference factors such as patterns, water droplets, and reflections when the detection mechanism directly detects the wafer surface. The detection stability is greatly improved and false judgments are reduced, effectively avoiding wafer damage, reducing production losses, improving yield and equipment safety. It does not depend on any characteristics of the wafer itself (type, surface film, polishing degree, etc.), and achieves universal compatibility with all known wafer types and manual / automatic plating head equipment. It is also compatible with various specifications and types of wafers. The optical path of the detection mechanism can be adjusted, which greatly improves the applicability and practicality of the detection technology. Attached Figure Description

[0037] Figure 1 This is a flowchart of a preferred embodiment of the wafer tilt detection method of the present invention.

[0038] Figure 2 This is a perspective view of a wafer tilting detection device according to a preferred embodiment of the present invention.

[0039] Figure 3 This is a diagram showing the positional relationship between the outer edge of the wafer and the beam of the detection mechanism in a preferred embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the structure of a plating head used to adsorb the surface of a wafer, according to a preferred embodiment of the present invention.

[0041] Figure 5 This is a diagram showing the positional relationship between the detection mechanism and the wafer in a preferred embodiment of the present invention.

[0042] Figure 6 This is a perspective view of a bracket according to a preferred embodiment of the present invention.

[0043] Figure 7 This is a diagram showing the positional relationship between the detection mechanism and the support in a preferred embodiment of the present invention.

[0044] Figure 8 This is a diagram showing the positional relationship between the bracket and the plating head in a preferred embodiment of the present invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1. Plating head; 11. Surface; 2. Wafer; 3. Inspection mechanism; 31. Inspection area; 4. Support; 41. Mounting plate; 42. Mounting hole. Detailed Implementation

[0047] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0048] This embodiment provides a method for detecting wafer tilt, specifically as follows: Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the wafer tilt detection method is used to detect the state of wafer 2 on plating head 1. The wafer tilt detection method includes the following steps:

[0049] S10. Construct a detection area 31 enclosed by at least three detection institutions 3, and construct the coverage area of ​​the detection area 31 to be larger than the area of ​​the wafer 2;

[0050] S20. The object being tested by the testing agency 3 is set as the surface 11 of the wafer 2 to be adsorbed by the plating head 1.

[0051] S30. Before the plating head 1 clamps the wafer 2 and closes the clamping action, the detection mechanism 3 is turned on and it is determined whether the outer edge of the wafer 2 extends out of the detection area 31. When the wafer 2 is within the detection area 31, the plating head 1 is closed and the wafer 2 is clamped. When the outer edge of the wafer 2 extends out of the detection area 31, the detection mechanism 3 triggers a signal to stop the plating head 1 from closing the clamping action of the wafer 2 and stops the clamping action of the wafer 2 accordingly.

[0052] Specifically, at least three detection mechanisms 3 are provided above the surface of the plating head 1 used to hold the wafer 2. These detection mechanisms 3 can be photoelectric, fiber optic, or displacement sensors as used in the prior art, and will not be elaborated upon here. The at least three detection mechanisms 3 enclose a detection area 31, which has the same shape as the wafer 2. The surface of the detection area 31 is not the surface of the wafer 2, but rather the surface of the plating head 1 used to hold the wafer 2. The detection area 31 is slightly larger than the outer edge of the wafer 2, so that if the wafer 2 is tilted when it is on the plating head 1, its outer edge extends out of the detection area 31 and is detected by the detection mechanism 3. When the wafer 2 is not tilted, its outer edge does not extend out of the detection area 31, remaining within it. In this case, the plating head 1 stops holding the wafer 2 and continues to perform the next electroplating or other processing steps on the wafer 2.

[0053] The process of loading wafer 2 onto plating head 1 and adsorbing it in this embodiment is a step in the prior art. This embodiment does not improve upon it and will not elaborate further here.

[0054] This embodiment uses a plating head 1 with uniform material, consistent surface brightness, and no water droplets covering it during operation to adsorb the surface of the wafer 2. This completely eliminates the problem of inaccurate detection of whether the wafer 2 is in a "skewed" state caused by interference factors such as patterns, water droplets, and reflections when the detection mechanism 3 directly detects the surface of the wafer 2. The detection stability is greatly improved and false judgments are reduced. Stopping the plating head 1 and closing the wafer 2 clamping action effectively avoids damage to the wafer 2, reduces production losses, and improves yield and equipment safety. In addition, the detection method in this embodiment does not depend on any characteristics of the wafer 2 itself (type, surface film, polishing degree, etc.), achieving universal compatibility with all known wafer types and manual / automatic plating head equipment. It is also compatible with various specifications and types of wafers. The optical path of the detection mechanism can be adjusted, greatly improving the applicability and practicality of the detection technology.

[0055] Furthermore, in this embodiment, step S10 further includes the following step:

[0056] The detection end of the detection mechanism 3 is directed vertically or tilted toward the plating head 1 to adsorb the surface 11 of the wafer 2.

[0057] Specifically, taking the example where the detection end of the detection mechanism 3 is perpendicularly oriented towards the surface 11 of the plating head 1 used to adsorb the wafer 2, the light beam emitted from the detection end is perpendicularly irradiated onto the surface 11, and the light beams emitted by multiple detection mechanisms 3 surround each other to form a detection area 31, so as to effectively cover the outer periphery of the outer edge of the wafer 2. Of course, if the space above the surface 11 is limited, the detection end can also be tilted towards the surface 11, with the same purpose of forming a continuous and complete detection area 31 on the outer periphery of the outer edge of the wafer 2.

[0058] In this embodiment, step S10 further includes the following step:

[0059] At least three detection units 3 are spaced apart and evenly distributed above the wafer 2. Compared to the uneven distribution between adjacent detection units 3 in the at least three detection units 3, the detection units 3 spaced apart and evenly distributed above the wafer 2 have no blind spots in coverage, avoiding misjudgment or missed judgment in wafer 2 tilt detection.

[0060] In this embodiment, step S30 further includes the following step:

[0061] When the detection mechanism 3 is turned on, the distance is measured using the light beam emitted by the detection mechanism 3. When the distance between the light beam emitted by the detection mechanism 3 and the object detected by the detection mechanism 3 is lower than the preset value, it is determined that the outer edge of the wafer 2 extends out of the detection area 31.

[0062] Specifically, the distance between the beam emitted by the detection mechanism 3 and the surface 11 is preset. If the wafer 2 is tilted, when the outer edge of the wafer 2 extends out of the detection area 31, the wafer 2 will block the beam emitted by at least one detection mechanism 3, which will cause the distance measurement value to be different from the preset value. The reflected signal received by the detection mechanism 3 will change abruptly. After receiving this change, the signal processing unit of the detection mechanism 3 will instantly determine that it is in a "tilted" state, which can immediately trigger an alarm signal and prevent the plating head 1 from closing, thus avoiding damage to the wafer 2.

[0063] If wafer 2 remains within the detection area 31, the detection mechanism 3 will not send a signal. By setting the detection object to the surface 11 on the plating head 1, rather than the surface of wafer 2, and using distance measurement for judgment, the problem of inaccurate detection of whether wafer 2 is in a "tilted" state due to interference factors such as wafer 2 patterns, water droplets, and reflections is overcome. It is understandable that wafer 2 needs to be cleaned during the loading and unloading process, so water droplets may remain on the surface of wafer 2, causing the light beam to directly illuminate the surface of wafer 2 and resulting in inaccurate distance measurement.

[0064] In this embodiment, step S10 further includes the following step:

[0065] When constructing the detection area 31, the difference between the coverage area of ​​the detection area 31 and the outer edge of the wafer 2 is set to 0-2mm. The detection accuracy is improved by limiting the difference between the range of the detection area 31 and the outer edge of the wafer 2.

[0066] This embodiment also provides a wafer tilt detection device, which uses the above-described wafer tilt detection method to detect the state in which the wafer 2 is located within the plating head 1. The wafer tilt detection device includes:

[0067] Support 4 is positioned above the wafer 2 that is adsorbed by the plating head 1, and multiple mounting plates 41 are provided on the support 4.

[0068] The detection mechanism 3 is provided in at least three parts. The at least three detection mechanisms 3 are detachably connected to the mounting plate 41 and electrically connected to the plating head 1. The detection ends of the at least three detection mechanisms 3 are vertically or inclined toward the surface 11 of the wafer 2 to be adsorbed by the plating head 1 and enclose a detection area 31 larger than the wafer 2. When the wafer 2 is located within the detection area 31, the plating head 1 performs the action of closing the clamping action of the wafer 2. When the outer edge of the wafer 2 extends out of the detection area 31, the detection mechanism 3 sends a signal to stop the action of the plating head 1 to close the clamping action of the wafer 2.

[0069] Specifically, the bracket 4 has a disc structure with a perforated structure to allow it to be snapped or connected to the surface 11. The mounting plate 41 extends perpendicularly to the surface of the bracket 4 and towards the surface 11, and is arranged radially along the bracket 4. Through holes can be provided on the mounting plate 41, allowing the detection mechanism 3 to be connected to the mounting plate 41 via bolts inserted through these holes, thus enabling a detachable connection between the detection mechanism 3 and the mounting plate 41. Furthermore, to ensure that the detection mechanism 3 can transmit signals, it can be electrically connected to the plating head 1, so that the signals emitted by the detection mechanism 3 can be transmitted to the plating head 1 and effectively stop its operation.

[0070] In this embodiment, at least three detection mechanisms 3 are spaced apart from each other in the circumferential direction around the support 4, and the central angles corresponding to the areas between two adjacent detection mechanisms 3 are the same.

[0071] Specifically, taking three testing institutions 3 as an example, the central angle between the areas of the three testing institutions 3 is 120°, that is, each testing institution 3 equally divides the position of the support 4 in the circumferential direction. The area covered by each testing institution 3 on the surface 11 is the same, and the three testing institutions 3 cooperate with each other to effectively form a testing area 31 that fully covers the outer edge of the wafer 2.

[0072] In this embodiment, a plurality of mounting holes 42 are provided at intervals on the mounting plate 41 along the radial direction of the bracket 4, and the detection mechanism 3 is connected to the mounting plate 41 through the mounting holes 42.

[0073] Specifically, part of the inspection mechanism 3 is used to pass through the mounting hole 42 to achieve connection with the mounting plate 41. Multiple mounting holes 42 are arranged at intervals along the radial direction of the bracket 4. When the wafer skew inspection device is used to inspect wafers 2 of different specifications such as 6 inches or 8 inches, the range of the inspection area 31 can be changed by passing the inspection mechanism 3 through and installing it in the mounting holes 42 at different positions, thereby ensuring inspection accuracy and a wider range of applicability of the inspection device.

[0074] In this embodiment, the detection area 31 is located on the same surface 11 of the plating head 1 used to adsorb the wafer 2.

[0075] Specifically, surface 11 is a plane below the end of wafer 2 for adsorption. This plane remains dry and has a uniform surface roughness because it does not participate in the cleaning of wafer 2. There is no need to worry about water droplets accumulating on surface 11 causing deviations in the ranging value of the ranging beam. In this embodiment, the plane, i.e., surface 11, is set to a horizontal plane, and the preset value of the ranging beam emitted by the detection mechanism 3 can be set to the same value, reducing parameter settings.

[0076] Of course, in other embodiments, the detection area 31 includes at least one detection end of a detection mechanism 3 that is perpendicular or inclined toward the plating head 1 and is different from the surface of the plating head 1 used to adsorb the wafer 2.

[0077] Specifically, the object of detection by at least one detection mechanism 3 is a plane different from surface 11. For example, the light beams emitted by two detection mechanisms 3 are located on the surface 11 of the plating head 1 used to adsorb the wafer 2, while the light beam emitted by one detection mechanism 3 can also form an effective detection area if it is located above or below the surface 11 of the plating head 1 used to adsorb the wafer 2. It can be understood that due to the continuity of the light beams, even if the object of detection by at least one detection mechanism 3 is a plane different from surface 11, a complete and continuous detection area 31 can be formed. The constructed detection area 31, viewed from the side of the plating head 1, is an arc-shaped range whose heights are not on the same plane.

[0078] In this embodiment, the detection mechanism 3 is a laser displacement sensor. Compared to a visual sensor, the distance measurement data obtained by using the laser displacement sensor in this embodiment is more accurate. The detection accuracy is improved by determining whether the wafer 2 extends beyond the detection area 31 and blocks the light path of the beam, thus causing a change in the distance measurement value.

[0079] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for detecting wafer skewness, wherein the method is used to detect the wafer state on a plating head, characterized in that, The wafer tilt detection method includes the following steps: S10. Construct a detection area enclosed by at least three detection institutions, and construct the coverage area of ​​the detection area to be larger than the area of ​​the wafer; S20. The object detected by the detection mechanism is set as the surface of the wafer for the plating head to adsorb the wafer. S30. Before the plating head clamps the wafer and closes the clamping action, the detection mechanism is turned on and it is determined whether the outer edge of the wafer extends out of the detection area. When the wafer is within the detection area, the plating head is closed and the wafer is clamped. When the outer edge of the wafer extends out of the detection area, the detection mechanism triggers a signal to stop the plating head from closing the clamping action of the wafer and stops the clamping action of the wafer accordingly.

2. The wafer ramp detection method of claim 1, wherein, Step S10 also includes the following steps: The detection end of the detection mechanism is directed vertically or tilted toward the plating head to adsorb the surface of the wafer.

3. The wafer ramp detection method of claim 1, wherein, Step S10 also includes the following steps: At least three of the aforementioned detection mechanisms are spaced apart and evenly distributed above the wafer.

4. The wafer ramp detection method of claim 1, wherein, Step S30 also includes the following steps: When the detection mechanism is turned on, the light beam emitted by the detection mechanism is used for distance measurement. When the distance between the light beam emitted by the detection mechanism and the object being detected by the detection mechanism is lower than a preset value, it is determined that the outer edge of the wafer extends beyond the detection area.

5. The wafer skew detection method as described in claim 1, characterized in that, Step S10 also includes the following steps: When constructing the detection area, the difference between the coverage area of ​​the detection area and the outer edge of the wafer is set to 0-2mm.

6. A wafer tilting detection device, wherein the wafer tilting detection device uses the wafer tilting detection method as described in any one of claims 1-5 to detect the state of the wafer being located within the plating head, characterized in that, The wafer tilting inspection device includes: A support is provided above the wafer that the plating head is used to adsorb; the support is provided with multiple mounting plates. The detection mechanism includes at least three detection mechanisms, which are detachably connected to the mounting plate and electrically connected to the plating head. The detection ends of the at least three detection mechanisms are perpendicular or inclined toward the surface of the wafer to be adsorbed by the plating head and enclose a detection area larger than the wafer. When the wafer is located within the detection area, the plating head performs a closing clamping action on the wafer. When the outer edge of the wafer extends beyond the detection area, the detection mechanism sends a signal to stop the plating head from closing the clamping action on the wafer.

7. The wafer tilting detection device as described in claim 6, characterized in that, At least three of the detection mechanisms are spaced apart from each other in the circumferential direction of the support, and the central angles corresponding to the areas between two adjacent detection mechanisms are the same.

8. The wafer tilting detection device as described in claim 6, characterized in that, Along the radial direction of the bracket, a plurality of mounting holes are provided at intervals on the mounting plate, and the detection mechanism is connected to the mounting plate through the mounting holes.

9. The wafer tilting detection device as described in claim 6, characterized in that, The detection area is located on the same surface of the wafer used by the plating head to adsorb the wafer; And / or, the detection area includes at least one detection end of the detection mechanism that is perpendicular or inclined toward the plating head and is different from the surface of the plating head used to adsorb the wafer.

10. The wafer tilting detection device as described in claim 6, characterized in that, The detection mechanism is a laser displacement sensor.

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