Clamping force measuring device and method of wafer clamping device

Abstract

The invention discloses a clamping force measuring device and a clamping force measuring method for a wafer clamping device. The wafer clamping device comprises an ejector pin used for clamping a wafer, and the clamping force measuring device comprises a wafer simulation disc, the edge of which is provided with a plurality of installation grooves; and the plurality of clamping force measuring units are respectively arranged in the corresponding mounting grooves, and the clamping force measuring units are configured to be in contact with the ejector pin so as to measure the clamping force of the ejector pin. According to the invention, the plurality of clamping force measuring units corresponding to the thimbles are arranged on the wafer simulation disc, so that the clamping force of the plurality of thimbles can be measured at a time, and the measuring efficiency is improved; meanwhile, the clamping force measuring unit is simple in structure, low in cost and convenient to operate; and the clamping force of all ejector pins on the whole wafer clamping device can be detected at one time, so that the accuracy of clamping force measurement is ensured. Therefore, the clamping force of the ejector pin can be measured more accurately, and the precision and the stability in the wafer machining process are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing, and particularly relates to a clamping force measuring device and a measuring method for a wafer clamping device. Background Art

[0002] In the wafer cleaning process, the chuck holds and rotates the wafer from multiple angles through multiple ejector pins, and at the same time, the chemical liquid sprayed from the nozzle above the wafer is used to clean the wafer surface. The clamping force of the ejector pins on the wafer has a significant impact on the process effect and the part life. On the one hand, if the clamping force is too small, the friction between the wafer and the ejector pins is insufficient, which will cause relative slippage between the two, and ultimately result in the splashing of the chemical liquid and excessive wear of the ejector pins. On the other hand, if the clamping force is too large, the ejector pins are overloaded, which is prone to fracture or deformation failure.

[0003] Although designers have obtained valuable estimated values for the clamping force by establishing a contact theoretical model between the wafer and the ejector pins and performing theoretical calculations, the accuracy cannot be guaranteed. The main reason for the lack of accuracy guarantee lies in the complexity of friction and local plastic deformation of the ejector pins. Therefore, it is of practical significance and necessity to actually measure the clamping force through experiments. At present, when detecting the clamping force of the ejector pins in this field, generally, a sensor and a controller are set on a workpiece simulating the wafer, and the two cooperate to perform intelligent measurement of the ejector pin clamping force. However, the clamping force measuring device of this method has a high manufacturing cost. Therefore, when setting it up, in order to reduce costs, generally, a sensor is selected to be set on the workpiece simulating the wafer to measure the clamping force of the ejector pins. This results in the clamping force of only one ejector pin being measured at a time. When multiple ejector pins are set on the chuck, after measuring the clamping force of one ejector pin, the workpiece needs to be rotated to continue measuring the clamping force of the next ejector pin. This will lead to, on the one hand: multiple repeated measurement operations are required, and zeroing is required for each measurement of the clamping force of an ejector pin, resulting in low measurement efficiency; on the other hand, there are errors in the roundness accuracy of the workpiece during the processing, and there will be positioning errors after each rotation of the workpiece, which will lead to errors in the measurement of the clamping force.

[0004] Therefore, it is necessary to study new methods to improve the efficiency and accuracy of ejector pin clamping force measurement. Summary of the Invention

[0005] In order to improve the accuracy and convenience of the clamping force detection of the wafer clamping device, the present invention provides a clamping force measuring device and a measuring method for the wafer clamping device.

[0006] On the one hand, a clamping force measuring device for a wafer clamping device, the wafer clamping device includes ejector pins for clamping a wafer, and the clamping force measuring device includes:

[0007] A wafer simulation disk, wherein a plurality of mounting grooves are formed in the edge of the wafer simulation disk;

[0008] A plurality of clamping force measuring units are respectively arranged in the corresponding mounting grooves, and the clamping force measuring unit is configured to contact the ejector pin to measure the clamping force of the ejector pin.

[0009] According to the specific implementation manner of the embodiment of the present application, the clamping force measuring unit includes:

[0010] A main scale, which is fixedly arranged on the side wall of the mounting groove;

[0011] A vernier scale, which is configured to be movable along the length direction of the main scale;

[0012] An elastic member, one end of the elastic member is fixedly connected to the vernier scale, and the other end of the elastic member is fixedly connected to the wafer simulation disk;

[0013] The clamping force measuring unit is configured to: during the measurement process, the ejector pin applies a clamping force to the vernier scale, the vernier scale transmits the clamping force to the elastic member, and the elastic member is compressed to generate deformation.

[0014] According to the specific implementation manner of the embodiment of the present application, the zero scale of the main scale coincides with the edge of the wafer simulation disk.

[0015] According to the specific implementation manner of the embodiment of the present application, the clamping force measuring unit is further configured to: based on Hooke's law and the deformation amount of the elastic member in the horizontal direction, measure the clamping force of the ejector pin.

[0016] According to the specific implementation manner of the embodiment of the present application, the clamping force measuring device further includes a controller communicatively connected to the clamping force measuring unit, and the controller is configured to: preset a target value of the clamping force, compare the measured clamping force with the target value, and when the measured clamping force is not equal to the target value, the controller issues a reminder message.

[0017] According to the specific implementation manner of the embodiment of the present application, the controller is further configured to: compare the clamping forces of the plurality of measured ejector pins, and when the clamping forces of the plurality of ejector pins are not equal, the controller issues a reminder message.

[0018] According to the specific implementation manner of the embodiment of the present application, the clamping force measuring device further includes: a guiding mechanism, which is configured to keep the vernier scale and the elastic member of the clamping force measuring unit moving in the length direction of the main scale.

[0019] According to the specific implementation manner of the embodiment of the present application, the guiding mechanism includes:

[0020] A guide rail, on which a sliding groove is formed, and the extending direction of the sliding groove is parallel to the length direction of the main scale;

[0021] A slider, on which a convex block matching the sliding groove is provided, the slider is slidably connected to the sliding groove through the convex block, and the slider is fixedly connected to the vernier scale.

[0022] On the other hand, a method for measuring the clamping force of a wafer clamping device. The clamping force measuring device is placed on the chuck of the wafer clamping device. The clamping force measuring units of the clamping force measuring device are arranged in one-to-one correspondence with the thimbles for clamping the wafer. Each clamping force measuring unit abuts against the corresponding thimble to measure the clamping force of the thimble. Among them, the clamping force measuring device includes:

[0023] A wafer simulation disk, on the edge of which a plurality of mounting grooves are formed;

[0024] A plurality of clamping force measuring units, which are arranged in the mounting grooves.

[0025] The clamping force measuring device and the measuring method of the wafer clamping device of the present invention can measure the clamping forces of a plurality of thimbles at one time by arranging a plurality of clamping force measuring units corresponding to the thimbles on the wafer simulation disk, thereby improving the measuring efficiency. At the same time, the clamping force measuring unit of the present invention has a simple structure, low cost and convenient operation. Moreover, it can detect the clamping forces of all the thimbles on the entire wafer clamping device at one time, avoiding the phenomenon that due to the inconsistent roundness of the edge area of the wafer simulation disk, when measuring the thimbles one by one, the contact parts of the thimbles change after rotating the wafer simulation disk, and then the forces applied by the thimbles will deviate, resulting in measurement errors, and ensuring the accuracy of the clamping force measurement. Therefore, the present invention can measure the clamping force of the thimble more accurately, and ensure the accuracy and stability in the wafer processing process.

[0026] Other features and advantages of the present invention will be described in the following description of the specification, and part of them will become obvious from the description of the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures pointed out in the specification, the claims and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 A schematic structural diagram of a wafer clamping device according to an embodiment of the present invention is shown;

[0029] Figure 2 The structural schematic diagram when a wafer according to an embodiment of the present invention is disposed on a wafer clamping device is shown;

[0030] Figure 3 The structural schematic diagram when a clamping force measuring device according to an embodiment of the present invention replaces the wafer and is assembled on the wafer clamping device is shown;

[0031] Figure 4 The structural schematic diagram of a clamping force measuring device according to an embodiment of the present invention is shown;

[0032] Figure 5 It shows Figure 3 The enlarged partial view of AC in; and

[0033] Figure 6 The structural schematic diagram of a clamping force measuring device including a guiding mechanism according to an embodiment of the present invention is shown. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment 1

[0036] Before the wafer cleaning process starts, the wafer needs to be placed on a wafer clamping device. Please refer to Figure 1 and Figure 2, the wafer clamping device includes a chuck 100. The chuck 100 is connected to a large gear 300 through a bearing 200. The large gear 300 is concentrically arranged with the chuck 100 and the bearing 200. A number of ejector pins 400 are arranged around the large gear 300 in an annular array, and one end of the large gear 300 is meshed with the ejector pins 400. The other end of the ejector pin 400 is used to clamp the wafer 500. At least one spring 600 is arranged on the chuck 100. Exemplarily, four springs 600 are arranged in the embodiment of the present invention. One end of each spring 600 is fixedly connected to the chuck 100 respectively, and the other end of each spring 600 is connected to the large gear 300 respectively. At least one cylinder (not shown) is arranged on the large gear 300. The direction in which the cylinder drives the large gear 300 to rotate is opposite to the direction in which the spring 600 drives the large gear 300 to rotate. The spring 600 acts on the chuck 100 and the large gear 300, causing relative rotation between the two. The large gear 300 drives the ejector pins 400 to rotate so that the ejector pins 400 clamp the wafer. The greater the acting force of the spring 600, the greater the clamping force of the ejector pins 400 on the wafer. It should be understood that the driving method for the ejector pins 400 to clamp and release the wafer is not limited to the above structure. For example, a cylinder can also be used alone to drive the ejector pins 400 to clamp and release the wafer. The specific method for the ejector pins 400 to clamp and release the wafer can be set according to actual needs. The above structure is still used for exemplary illustration in the following exemplary description of this article.

[0037] During the cleaning process, a driving device (not shown) drives the chuck 100 to rotate, and the wafer 500 placed on the wafer clamping device rotates accordingly. At the same time, the chemical liquid flowing out from a nozzle (not shown) above the wafer 500 is used to clean the surface of the wafer 500. During the cleaning process, the clamping force of the ejector pins 400 on the wafer 500 has a significant impact on the process effect and the part life. Therefore, it is necessary to ensure the clamping force of the wafer 500 with high precision. In the prior art, when measuring the clamping force of the ejector pins, on the one hand, the cost is high and the operation is complex. On the other hand, and more critically, errors will occur during the process of measuring the clamping forces of multiple ejector pins separately.

[0038] To solve the above problems, the embodiment disclosed in the present invention provides a clamping force measuring device for a wafer clamping device. Please refer to Figure 3, the device includes: a wafer simulation disk 700 and a plurality of clamping force measurement units 800. The wafer simulation disk 700 simulates a real wafer 500 and is configured to act as the wafer 500 during the cleaning process when measuring the thimble clamping force. An installation groove 701 corresponding to the thimble is formed at the edge of the wafer simulation disk 700, and a plurality of clamping force measurement units 800 are respectively arranged in the installation groove 701. The clamping force measurement unit 800 is configured to contact the thimble 400 to measure the thimble clamping force. It should be understood that the number of the clamping force measurement units 800 should be at least equal to the number of the thimbles 400, and the set positions should match the positions of the thimbles 400, so that when using the clamping force measurement device to measure the clamping force, a plurality of thimbles 400 can simultaneously contact the corresponding clamping force measurement units 800 to synchronously measure the clamping force.

[0039] Specifically, please refer to Figure 4 , the clamping force measurement unit 800 includes a main scale 801, a vernier scale 802, and an elastic member 803. The main scale 801 is fixedly arranged on the side wall 7011 of the installation groove 701 formed in the wafer simulation disk 700, and the zero scale of the main scale 801 coincides with the edge of the wafer simulation disk 700. The vernier scale 802 is arranged below the main scale 801, parallel to the main scale 801, and can move along the length direction of the main scale 801. One end of the vernier scale 802 away from the zero scale of the main scale 801 is connected to one end of the elastic member 803. The elastic member 803 is horizontally arranged, and the other end of the elastic member 803 is connected to the bottom wall 7012 of the installation groove 701. Exemplarily, the elastic member 803 includes but is not limited to a leaf spring, a helical spring, a diaphragm, a bellows, etc., and can be specifically selected according to actual process requirements. Further, the elastic coefficient of the elastic member 803 can be 1 - 10 N / m.

[0040] Please combine Figure 1 , Figure 4 and Figure 5, when measuring the thimble clamping force, the clamping force measuring device is placed on the chuck 100 of the wafer clamping device instead of the wafer 500 in the cleaning process, and the vernier 802 of the clamping force measuring unit 800 of the clamping force measuring device is aligned with the thimble 400 respectively, and then the thimble 400 clamps the vernier 802. The thimble 400 applies a force in the horizontal direction to the center of the wafer simulation disk 700 to push the vernier 802 to move horizontally towards the center of the wafer simulation disk 700, and then transmits the clamping force of the thimble 400 to the elastic member 803. The elastic member 803 is subjected to a clamping force in the horizontal direction and is compressed to generate deformation. At this time, the deformation amount of the elastic member 803 can be obtained as a specific value by combining the main scale 801 and the vernier 802. Based on the deformation amount of the elastic member 803 in the horizontal direction, the thimble clamping force is calculated by conversion in combination with Hooke's law of elasticity. Exemplarily, when the elastic member 803 selects a helical spring with a spring constant of 2 N / mm, during the measurement process, the deformation amount of the elastic member 803 is 5 mm, then according to Hooke's law of elasticity, the clamping force of the thimble 400 at this time can be calculated as 10 N. It should be understood that when the elastic member 803 is selected, the elastic coefficient of the elastic member 803 is a fixed value, and the scales on the main scale 801 and the vernier 802 can be the deformation amount of the elastic member 803 or the force value after conversion based on the law of elasticity.

[0041] By arranging a plurality of clamping force measuring units 800 corresponding to the thimbles 400 on the wafer simulation disk 700, the present application can measure the clamping forces of multiple thimbles 400 at one time, improving the measurement efficiency. The structure of this clamping force measuring unit 800 is simple, the cost is low, and the operation is convenient; at the same time, it can detect the clamping forces of all the thimbles 400 on the entire wafer clamping device at one time, avoiding the phenomenon that due to the inconsistent roundness of the edge area of the wafer simulation disk, when measuring the thimbles 400 one by one, the contact part of the thimble 400 changes after rotating the wafer simulation disk 700, and then the force applied by the thimble 400 will deviate, resulting in measurement errors, ensuring the accuracy of the clamping force measurement. Therefore, the present application can measure the thimble clamping force more accurately, ensuring the accuracy and stability in the wafer processing process.

[0042] Furthermore, in order to ensure that the moving directions of the elastic member 803 and the vernier 802 are along the length direction of the main scale 801, the clamping force measuring device further includes: a guiding mechanism. The guiding mechanism is configured to keep the vernier 802 and the elastic member 803 of the clamping force measuring unit moving in the length direction of the main scale 801.

[0043] Specifically, please refer to Figure 6 , the guiding mechanism includes: a guide rail 901 and a slider 902.

[0044] The guide rail 901 is a strip-shaped structure, and the extending direction of its length is the setting direction of the vernier 802. A chute 903 is provided on the end face of the guide rail 901 along the extending direction of its length. A slider 902 is slidably disposed on the guide rail 901. A convex block 904 matching the chute 903 is provided on the slider 902, and the slider 902 is fixedly connected to the vernier 802. In this embodiment, the guiding mechanism is disposed above the vernier 802. Therefore, in this example, the chute 903 is provided on the lower end face of the guide rail 901, and the upper end face of the convex block 904 disposed in matching with the chute 903 is disposed in the chute 903, and the lower end face of the slider 902 is fixedly connected to the upper end face of the vernier 802. During the measurement of the clamping force, when the thimble 400 pushes the vernier 802 to move, under the restricting action of the slider 902 and the guide rail 901, the vernier 802 and the elastic member 803 are pushed to move only in the length direction of the main scale 801, thereby ensuring the accuracy of the detection.

[0045] It should be understood that the setting manner of the guiding mechanism illustrated in the embodiments of the present invention does not limit the actual structure and setting manner of the guiding mechanism. During actual use, the guiding mechanism may be the structure of this embodiment but disposed below the vernier, or may be other components that can enable the vernier and the elastic member to move in the length direction of the main scale.

[0046] Embodiment 2

[0047] This embodiment provides a clamping force measuring device for a wafer clamping device. The structure of the clamping force measuring device of the wafer clamping device is basically the same as that of the clamping force measuring device of the wafer clamping device in Embodiment 1. The difference is that the clamping force measuring device further includes a controller communicatively connected to the clamping force measuring unit. During the measurement process, a target value of the thimble clamping force is preset in advance. The controller is configured to: compare the measured clamping force with the preset target value of the thimble clamping force. When the measured thimble clamping force is not equal to the preset target value, the controller issues a reminder message to remind the staff to adjust the thimble clamping force to reach the target value. It should be noted that when clamping wafers with the same wafer clamping device, different types and sizes of wafers require different clamping forces. Therefore, when presetting the target value of the thimble clamping force, it is also necessary to set according to the type and size of the wafer. It should be understood that in the context of this embodiment, "equal" allows a certain deviation range. For example, if the error between the measured thimble clamping force and the preset target value of the thimble clamping force is within ±10%, it is considered normal. If it exceeds ±10%, it is considered abnormal, and the controller will issue a reminder message.

[0048] Embodiment 3

[0049] This embodiment provides a clamping force measuring device for a wafer clamping device. The structure of the clamping force measuring device for the wafer clamping device is basically the same as that of the clamping force measuring device for the wafer clamping device in Embodiment 2. The difference is that when the clamping force requirements of multiple ejector pins 400 on the same wafer clamping device are equal, the controller is further configured to: compare the measured clamping forces of the multiple ejector pins 400, and when the clamping forces of the multiple ejector pins 400 are not equal, the controller issues a reminder message.

[0050] Specifically, in the actual process, the clamping forces of multiple ejector pins 400 on the same wafer clamping device can be equal or not equal, and need to be adjusted according to process requirements. When the clamping force requirements of the ejector pins 400 on the same wafer clamping device are equal, the controller compares the clamping forces of each ejector pin 400. When the clamping forces of the multiple ejector pins 400 are not equal, it indicates that the clamping force of some ejector pins does not meet the requirements. At this time, the controller issues a reminder message to remind the staff to adjust the clamping force of the ejector pins to reach the target value, and the clamping forces of each ejector pin 400 are adjusted to be equal. Similarly, in the context of this embodiment, "equal" allows a certain deviation range. For example, if the difference in the clamping forces of any two measured ejector pins is within the set range, such as 0 - 0.5N, it is considered normal. If it exceeds the set range, it is considered abnormal, and the controller will issue a reminder message.

[0051] Embodiment 4

[0052] The embodiment of the present invention provides a method for measuring the clamping force of a wafer clamping device. The clamping force measuring device is placed on the chuck of the wafer clamping device. The clamping force measuring units of the clamping force measuring device are arranged in one-to-one correspondence with the ejector pins for clamping the wafer. Each clamping force measuring unit abuts against the corresponding ejector pin to measure the clamping force of the ejector pin; wherein, the clamping force measuring device includes:

[0053] A wafer simulation disk, with a plurality of mounting grooves formed at the edge of the wafer simulation disk;

[0054] A plurality of clamping force measuring units, arranged in the mounting grooves.

[0055] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A clamping force measuring device for a wafer clamping device, the wafer clamping device including a thimble for clamping a wafer, characterized in that: The clamping force measuring device includes: A wafer simulation disk, with a plurality of mounting grooves formed at the edge of the wafer simulation disk; A plurality of clamping force measuring units, respectively arranged in the corresponding mounting grooves, and the clamping force measuring units are configured to contact the thimble to measure the clamping force of the thimble.

2. The clamping force measuring device according to claim 1, wherein: The clamping force measuring unit includes: A main scale, which is fixedly arranged on the side wall of the mounting groove; A vernier scale, which is configured to be movable along the length direction of the main scale; An elastic member, one end of the elastic member is fixedly connected to the vernier scale, and the other end of the elastic member is fixedly connected to the wafer simulation disk; The clamping force measuring unit is configured to: during the measurement process, the thimble applies a clamping force to the vernier scale, the vernier scale transmits the clamping force to the elastic member, and the elastic member is compressed to generate deformation.

3. The clamping force measuring device according to claim 2, characterized in that: The zero scale of the main scale coincides with the edge of the wafer simulation disk.

4. The clamping force measuring device according to claim 2, wherein: The clamping force measuring unit is further configured to: measure the clamping force of the thimble based on Hooke's law in combination with the deformation amount of the elastic member in the horizontal direction.

5. The clamping force measuring device according to claim 1, wherein: The clamping force measuring device further includes a controller communicatively connected to the clamping force measuring unit, and the controller is configured to: preset a target value of the clamping force, compare the measured clamping force with the target value, and when the measured clamping force is not equal to the target value, the controller issues a reminder message.

6. The clamping force measuring device according to claim 1, wherein: The clamping force measuring device further includes a controller communicatively connected to the clamping force measuring unit, and the controller is configured to: compare the measured clamping forces of multiple thimbles, and when the clamping forces of multiple thimbles are not equal, the controller issues a reminder message.

7. The clamping force measuring device according to claim 2, wherein: The clamping force measuring device further includes: a guiding mechanism, which is configured to keep the vernier scale and the elastic member of the clamping force measuring unit moving in the length direction of the main scale.

8. The clamping force measuring device according to claim 7, wherein: The guiding mechanism includes: A guide rail, with a chute formed on the guide rail, and the extending direction of the chute is parallel to the length direction of the main scale; A slider, with a convex block matching the chute provided on the slider, and the slider is slidably connected to the chute through the convex block, and the slider is fixedly connected to the vernier scale.

9. A method for measuring the clamping force of a wafer clamping device, wherein: Place the clamping force measuring device on the chuck of the wafer clamping device, and the clamping force measuring units of the clamping force measuring device are arranged in one-to-one correspondence with the thimbles for clamping the wafer, and each clamping force measuring unit abuts against the corresponding thimble to measure the clamping force of the thimble; wherein, the clamping force measuring device includes: A wafer simulation disk, with a plurality of mounting grooves formed at the edge of the wafer simulation disk; Multiple clamping force measurement units are arranged in the installation groove.

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