Wafer electrostatic chuck detection method

Abstract

The present application provides a method for detecting a wafer electrostatic chuck, which first obtains the Coulomb force threshold when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and the height threshold of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. Then, in a wafer-free state, a pressure gauge is used to obtain the pressure value when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and an altimeter is used to obtain the height value of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold to detect and determine the wafer electrostatic chuck. The method for detecting a wafer electrostatic chuck of the present application can successfully check whether the wafer electrostatic chuck meets the process technology requirements, thereby greatly reducing the risk of product scrapping and improving equipment utilization.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor equipment and relates to a method for detecting an electrostatic chuck of a wafer. Background Art

[0002] Electrostatic chuck (E-Chuck) is an advantageous technology that uses electrostatic adsorption technology to replace traditional mechanical clamping and vacuum adsorption methods. It is widely used in panel display, optics, semiconductors and other fields.

[0003] The E-Chuck (E-Chuck) is widely used in semiconductor ion implantation equipment. Its principle is to generate an electric field under high voltage, causing the wafer to adhere to the E-Chuck surface for ion implantation. The E-Chuck operates as follows: A high-voltage power supply applies a positive voltage to the E-Chuck, attracting electrons to the back of the wafer. The Coulomb force F, acting on the electrons and the positively charged E-Chuck, prevents the wafer from being affected by gravity and causing it to drop during the ion implantation process. When the ion implantation process is complete, the high voltage on the E-Chuck surface dissipates, and the Coulomb force on the wafer dissipates, releasing the wafer. However, residual charge remains on the wafer surface during the ion implantation process. Therefore, even if the high voltage on the E-Chuck surface is turned off, the wafer remains electrostatically attracted to the E-Chuck surface. If the robotic arm attempts to remove the wafer during this time, the residual electrostatic attraction may cause the wafer to fail, or even drop, resulting in product failure. To address this issue, existing E-chucks are equipped with a ground pin with a spring at the bottom. However, in actual use, this ground pin often fails to contact the wafer surface due to spring elasticity issues, or the spring fails to return to its original shape, resulting in wafer removal failure, wafer drop, and static electricity discharge issues.

[0004] Therefore, it is necessary to provide a method for detecting a wafer electrostatic chuck. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for detecting a wafer electrostatic chuck, so as to solve the problem in the prior art that the instability of the wafer electrostatic chuck affects the product.

[0006] To achieve the above-mentioned and other related purposes, the present application provides a method for detecting a wafer electrostatic chuck, comprising the following steps:

[0007] Providing a wafer electrostatic chuck, wherein the wafer electrostatic chuck is provided with a retractable grounding pin;

[0008] Obtaining a Coulomb force threshold when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and obtaining a height threshold at which the retractable grounding pin protrudes from the surface of the wafer electrostatic chuck;

[0009] In a wafer-free state, a pressure gauge is used to obtain a pressure value when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and an altimeter is used to obtain a height value of the retractable grounding pin protruding from the surface of the wafer electrostatic chuck;

[0010] The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold, so as to detect and determine whether the retractable grounding pin in the wafer electrostatic chuck is in a normal state.

[0011] Optionally, the method for obtaining the Coulomb force threshold when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck includes:

[0012] Obtaining equipment parameters of the wafer electrostatic chuck;

[0013] In combination with Coulomb's law, data processing is performed on the device parameters to obtain the corresponding Coulomb force threshold.

[0014] Optionally, the device parameters of the wafer electrostatic chuck include the thickness R of the insulating layer of the wafer electrostatic chuck, the voltage U applied to the wafer electrostatic chuck, and the capacitance C, and the device parameters of the wafer electrostatic chuck are substituted into the formula F 库仑力 =K·(U·C / R) 2 , to obtain the Coulomb force threshold, where K is the electrostatic constant.

[0015] Optionally, the thickness R is 15 microns to 25 microns, the voltage U is 650 volts to 1000 volts, and the capacitance C is 1E -6 Pharah ~ 4E -6 Farah.

[0016] Optionally, the height threshold range of the telescopic grounding pin includes 0.8 mm to 1.2 mm.

[0017] Optionally, when detecting and judging the wafer electrostatic chuck, when the height value is within the height threshold and when the obtained pressure value is less than the Coulomb force threshold, it is determined to be in a normal state.

[0018] Optionally, when it is determined to be an abnormal state, the method further includes replacing the retractable grounding pin.

[0019] Optionally, the pressure gauge includes a Newton pressure gauge; and the altimeter includes a vernier caliper.

[0020] Optionally, the number of the retractable grounding pins in the wafer electrostatic chuck ranges from 1 to 3, and when there are multiple retractable grounding pins, the retractable grounding pins are judged one by one.

[0021] Optionally, the detection method includes an electrostatic chuck for a wafer applied to a semiconductor ion implantation device.

[0022] As described above, the wafer electrostatic chuck detection method of the present application first obtains the Coulomb force threshold when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and the height threshold of the retractable grounding pin protruding from the surface of the wafer electrostatic chuck. Then, in the absence of a wafer, a pressure gauge is used to obtain the pressure value when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and an altimeter is used to obtain the height value of the retractable grounding pin protruding from the surface of the wafer electrostatic chuck. The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold to detect and determine the wafer electrostatic chuck. The wafer electrostatic chuck detection method of the present application can successfully check whether the wafer electrostatic chuck meets the process technology requirements, thereby greatly reducing the risk of product scrapping and improving equipment utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a flow chart of a method for detecting an electrostatic chuck of a wafer in an embodiment of the present application.

[0024] Figure 2 Shown is a schematic diagram of the structure of the wafer electrostatic chuck before adsorbing the wafer in an embodiment of the present application.

[0025] Figure 3 Shown is a schematic diagram of the state structure of the wafer electrostatic chuck when adsorbing the wafer in an embodiment of the present application.

[0026] Figure 4 Shown is a schematic structural diagram of the retractable grounding pin in an embodiment of the present application when the spring loses its elastic force.

[0027] Figure 5 It is a schematic diagram showing the structure when the spring of the telescopic grounding pin in the embodiment of the present application cannot return to its original shape.

[0028] Figure 6 Shown is a schematic diagram of the structure of the wafer electrostatic chuck when releasing the wafer in an embodiment of the present application.

[0029] Figure 7 Shown is a structural schematic diagram of obtaining the height value of the retractable grounding needle and the surface of the wafer electrostatic chuck in an embodiment of the present application.

[0030] Figure 8Shown is a structural schematic diagram of the pressure value obtained when the retractable grounding needle is flush with the surface of the wafer electrostatic chuck in an embodiment of the present application.

[0031] Component number description

[0032] 100 Wafer Electrostatic Chuck

[0033] 200 wafers

[0034] 300 telescopic ground pin

[0035] 301 ground pin

[0036] 302 Spring

[0037] Steps S1 to S4 DETAILED DESCRIPTION

[0038] The following describes the embodiments of the present application through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present application from the disclosure herein. The present application may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present application.

[0039] For example, when describing the embodiments of this application, cross-sectional views of device structures may be partially enlarged to a different scale for ease of explanation. Furthermore, these schematic views are merely illustrative and should not limit the scope of protection of this application. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0040] For ease of description, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may be present. As used herein, "between" is inclusive of both endpoints.

[0041] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0042] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner. Therefore, the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0043] like Figure 1 As shown, this embodiment provides a method for detecting a wafer electrostatic chuck, comprising the following steps:

[0044] S1: Providing a wafer electrostatic chuck, wherein the wafer electrostatic chuck is provided with a retractable grounding pin;

[0045] S2: Obtaining a Coulomb force threshold when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and obtaining a height threshold of the retractable grounding pin protruding from the surface of the wafer electrostatic chuck;

[0046] S3: In a wafer-free state, using a pressure gauge to obtain a pressure value when the retractable grounding pin is flush with the surface of the wafer electrostatic chuck, and using an altimeter to obtain a height value of the retractable grounding pin protruding from the surface of the wafer electrostatic chuck;

[0047] S4: Compare the obtained height value with the height threshold, and compare the obtained pressure value with the Coulomb force threshold, so as to detect and determine whether the retractable grounding pin in the wafer electrostatic chuck is in a normal state.

[0048] The detection method of the wafer electrostatic chuck of this embodiment first obtains the Coulomb force threshold when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and the height threshold of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. Then, in a wafer-free state, a pressure gauge is used to obtain the pressure value when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and an altimeter is used to obtain the height value of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold to detect and determine the wafer electrostatic chuck.

[0049] The wafer electrostatic chuck detection method of this embodiment can successfully check whether the wafer electrostatic chuck meets the process technology requirements, thereby greatly reducing the risk of product scrapping and improving equipment utilization.

[0050] The following combination Figures 2 to 8 The detection method of the wafer electrostatic chuck in this embodiment is further explained.

[0051] like Figure 2First, step S1 is performed to provide a wafer electrostatic chuck 100 , in which a retractable grounding pin 300 is provided.

[0052] Specifically, the retractable grounding pin 300 may include a grounding pin 301 and a spring 302 located below the grounding pin 301. The grounding pin 301 can be retracted and retracted by retracting and retracting the spring 302. The surface of the wafer electrostatic chuck 100 has a hole that can accommodate the grounding pin 301, and the retractable grounding pin 300 is grounded. Therefore, when the wafer electrostatic chuck 100 releases the wafer 200, the residual charge on the wafer 100 can be released through the grounding pin 301 in contact with the wafer 200. Figure 6 The schematic diagram of the structure of the wafer electrostatic chuck 100 when releasing the wafer 200 is shown. In the wafer-free state, the grounding pin 301 can be exposed in the hole (not shown) on the wafer electrostatic chuck 100 through the extension of the spring 302.

[0053] Figure 3 The schematic diagram of the structure of the wafer electrostatic chuck 100 in this embodiment shows the state of the wafer 200 being attracted. After the wafer 200 is placed on the surface of the wafer electrostatic chuck 100, a voltage U can be applied to the wafer electrostatic chuck 100, causing the wafer electrostatic chuck 100 to be positively charged, thereby attracting electrons to the back side of the wafer 200. The electron-carrying wafer 200 and the positively charged wafer electrostatic chuck 100, under the action of the Coulomb force F, can ensure that during the processing of the wafer 200, such as the ion implantation process, the wafer 200 is not affected by the gravitational force and thus does not fall off. After the process is completed, the high voltage acting on the surface of the wafer electrostatic chuck 100 is removed. As a result, the Coulomb force F acting on the wafer 200 will also disappear, releasing the wafer 200. However, there will still be residual charge on the surface of the wafer 200, such as during the ion implantation process. In this case, the retractable grounding pin 300 in contact with the back side of the wafer 200 can release the residual charge on the wafer 200, thereby avoiding wafer removal failure, wafer drop, and product scrapping.

[0054] like Figure 4 The schematic diagram shows the structure of the spring 302 of the retractable grounding pin 300 when the spring 302 loses its elastic force. In this case, the grounding pin 301 is not in contact with the wafer 200, and therefore, the residual charge in the wafer 200 is lost. Figure 5 The figure shows a structural diagram when the spring 302 of the retractable grounding pin 300 cannot return to its original state. This situation will also cause the wafer 200 to be unable to make good contact with the wafer electrostatic chuck 100, and there is a risk of wafer removal failure and wafer drop.

[0055] Next, step S2 is executed to obtain the Coulomb force threshold when the retractable grounding pin 300 is flush with the surface of the wafer electrostatic chuck 100 , and obtain the height threshold of the retractable grounding pin 300 protruding from the surface of the wafer electrostatic chuck 100 .

[0056] As an example, a method for obtaining a Coulomb force threshold when the retractable grounding pin 300 is flush with the surface of the wafer electrostatic chuck 100 includes:

[0057] Obtaining equipment parameters of the wafer electrostatic chuck 100;

[0058] In combination with Coulomb's law, data processing is performed on the device parameters to obtain the corresponding Coulomb force threshold.

[0059] The device parameters of the wafer electrostatic chuck 100 include the thickness R of the insulating layer of the wafer electrostatic chuck 100, the voltage U and the capacitance C applied to the wafer electrostatic chuck, and the device parameters of the wafer electrostatic chuck 100 are substituted into the formula F 库仑力 =K·Q1·Q2 / R 2 , and since Q1=Q2=U·C, then F 库仑力 =K·(U·C / R) 2 , so that the Coulomb force threshold can be obtained, where K is the electrostatic constant.

[0060] Specifically, the thickness R may be 15 μm to 25 μm, such as 15 μm, 25 μm, 25 μm, etc., the voltage U may be 650 V to 1000 V, such as 650 V, 800 V, 1000 V, etc., and the capacitance C may be 1E -6 Pharah ~ 4E -6 Farad, such as 1E -6 Farah, 2E -6 Pharah, 3E -6 Farad 4E -6 The device parameters of the wafer electrostatic chuck 100 can be selected according to the specific device type and product requirements, and are not overly limited here. The following table shows a comparison table of device parameters corresponding to several different models.

[0061]

[0062] Specifically, according to Coulomb's law F 库仑力 =K·Q1·Q2 / R 2, where K is the electrostatic constant, Q1=Q2=U·C, where U is the voltage applied to the wafer electrostatic chuck 100, which is a fixed value, R is the thickness of the insulating layer of the wafer electrostatic chuck 100, which is a fixed value, and C is the capacitance of the wafer electrostatic chuck 100, which is a fixed value. Substituting the above constants into the formula, we can get: F 库仑力 =K·(U·C / R) 2 , thereby obtaining the F of the wafer electrostatic chuck 100 库仑力 According to actual application, when the pressure value obtained later when the retractable grounding pin 300 is flush with the surface of the wafer electrostatic chuck 100 is less than the F 库仑力 When the value is 0, the wafer 200 has no abnormal phenomenon, otherwise the wafer 200 has a defective phenomenon, so the F 库仑力 The value is used as a threshold for determining the pressure value applied to the telescopic grounding pin 300 .

[0063] The method for determining the height threshold at which the retractable grounding pin 300 protrudes from the surface of the wafer electrostatic chuck 100 can be determined based on data accumulated in actual applications. The height threshold may vary depending on the product and equipment selected. Preferably, the height threshold of the retractable grounding pin is in the range of 0.8 mm to 1.2 mm, such as 0.8 mm, 1.0 mm, or 1.2 mm, without any undue restriction.

[0064] Next, execute step S3. In the wafer-free state, use a pressure gauge to obtain the pressure value F when the retractable grounding needle 300 is flush with the surface of the wafer electrostatic suction cup 100, and use an altimeter to obtain the height value Δh of the retractable grounding needle 300 protruding from the surface of the wafer electrostatic suction cup 100.

[0065] Specifically, the pressure gauge may include a Newtonian pressure gauge, and the altimeter may include a vernier caliper, but the types of the pressure gauge and the altimeter are not limited thereto and may be replaced as needed. Figure 7 It is a schematic diagram showing the structure of obtaining the height value Δh between the retractable grounding pin 300 and the surface of the wafer electrostatic chuck 100 in this embodiment. Figure 8 It is a structural diagram showing the pressure value F obtained when the retractable grounding pin 300 is flush with the surface of the wafer electrostatic chuck 100 in this embodiment.

[0066] Next, step S4 is executed to compare the obtained height value Δh with the height threshold, and to compare the obtained pressure value F with the Coulomb force threshold, so as to detect and determine whether the retractable grounding pin 300 in the wafer electrostatic chuck 100 is in a normal state.

[0067] Specifically, when inspecting and determining the wafer electrostatic chuck 100, if the height value Δh is within the height threshold and the obtained pressure value F is less than the Coulomb force threshold, the wafer is determined to be in a normal state. If the height value Δh exceeds the height threshold, or if the obtained pressure value F is less than the Coulomb force threshold, the wafer is determined to be in an abnormal state. In this case, the retractable grounding pin 300 can be replaced to obtain a suitable wafer electrostatic chuck 100, such as by replacing the spring 302.

[0068] As an example, the number of the telescopic grounding pins 300 in the wafer electrostatic chuck 100 may include 1 to 3, such as 1, 2, 3, etc., and when there are multiple telescopic grounding pins 300, the telescopic grounding pins 300 can be judged one by one to obtain the wafer electrostatic chuck 100 that meets the requirements. In this embodiment, the number of the telescopic grounding pins 300 is 2, but it is not limited to this.

[0069] As an example, the detection method may include application to a wafer electrostatic chuck of a semiconductor ion implantation device, but is not limited thereto.

[0070] In summary, the detection method of the wafer electrostatic chuck of the present application first obtains the Coulomb force threshold when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and the height threshold of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. Then, in the absence of a wafer, a pressure gauge is used to obtain the pressure value when the telescopic grounding pin is flush with the surface of the wafer electrostatic chuck, and an altimeter is used to obtain the height value of the telescopic grounding pin protruding from the surface of the wafer electrostatic chuck. The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold to detect and determine the wafer electrostatic chuck. The detection method of the wafer electrostatic chuck of the present application can successfully check whether the wafer electrostatic chuck meets the process technology requirements, thereby greatly reducing the risk of product scrapping and improving equipment utilization.

[0071] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A method for detecting a wafer electrostatic chuck, characterized in that: The following steps are involved: A wafer electrostatic chuck (100) is provided, wherein a retractable grounding pin (300) is provided in the wafer electrostatic chuck (100); Obtaining a Coulomb force threshold when the retractable grounding pin (300) is flush with the surface of the wafer electrostatic chuck (100), and obtaining a height threshold at which the retractable grounding pin (300) protrudes from the surface of the wafer electrostatic chuck (100); In a state where there is no wafer (200), a pressure gauge is used to obtain a pressure value when the retractable grounding pin (300) is flush with the surface of the wafer electrostatic chuck (100), and an altimeter is used to obtain a height value of the retractable grounding pin (300) protruding from the surface of the wafer electrostatic chuck (100); The obtained height value is compared with the height threshold, and the obtained pressure value is compared with the Coulomb force threshold, so as to detect and determine whether the telescopic grounding pin (300) in the wafer electrostatic chuck (100) is in a normal state.

2. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: The method for obtaining the Coulomb force threshold when the retractable grounding pin (300) is flush with the surface of the wafer electrostatic chuck (100) comprises: Obtaining equipment parameters of the wafer electrostatic chuck (100); In combination with Coulomb's law, data processing is performed on the device parameters to obtain the corresponding Coulomb force threshold.

3. The method for detecting a wafer electrostatic chuck according to claim 2, wherein: The device parameters of the wafer electrostatic chuck (100) include the thickness R of the insulating layer of the wafer electrostatic chuck (100), the voltage U applied to the wafer electrostatic chuck (100), and the capacitance C. The device parameters of the wafer electrostatic chuck (100) are substituted into the formula F 库仑力 =K·(U·C / R) 2 , to obtain the Coulomb force threshold, where K is the electrostatic constant.

4. The method for detecting a wafer electrostatic chuck according to claim 3, wherein: The thickness R is 15 microns to 25 microns, the voltage U is 650 volts to 1000 volts, and the capacitance C is 1E -6 Pharah ~ 4E -6 Farah.

5. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: The height threshold range of the telescopic grounding pin (300) includes 0.8 mm to 1.2 mm.

6. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: When the wafer electrostatic chuck (100) is detected and judged, when the height value is within the height threshold and when the obtained pressure value is less than the Coulomb force threshold, it is judged to be in a normal state.

7. The method for detecting a wafer electrostatic chuck according to claim 6, wherein: When it is determined to be an abnormal state, the method further includes the step of replacing the telescopic grounding pin (300).

8. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: The pressure gauge includes a Newtonian pressure gauge; the altimeter includes a vernier caliper.

9. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: The number of the retractable grounding pins (300) in the wafer electrostatic chuck (100) ranges from 1 to 3, and when there are a plurality of retractable grounding pins (300), the retractable grounding pins (300) are judged one by one.

10. The method for detecting a wafer electrostatic chuck according to claim 1, wherein: The detection method includes a wafer electrostatic chuck (100) applied to semiconductor ion implantation equipment.

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