Device and method for measuring residual electrostatic adsorption force

Abstract

The invention provides a device and a method for measuring residual electrostatic adsorption force. The device comprises a plurality of ejector pin supporting seats distributed in the circumferential direction, a plurality of pressure sensors, a plurality of vacuum penetration pieces, a fixed bottom plate and a data processing module. One pressure sensor is arranged at the upper end part of each ejector pin supporting seat; the lower end part of each ejector pin supporting seat is fixed on the fixed bottom plate; the upper end part of each vacuum through piece is in vacuum tight connection with one pressure sensor, and the lower end part of each vacuum through piece penetrates through the fixed bottom plate and is connected to the data processing module; and the data processing module is configured to calculate residual electrostatic adsorption force according to the signal transmitted by the pressure sensor and judge whether the wafer has a desorption condition or not.

Description

Technical Field

[0001] The present invention relates to semiconductor equipment, and in particular to a device and method for measuring residual electrostatic adsorption force. Background Art

[0002] In the current high-temperature carbon mask process, due to the high temperature of the wafer, the bow value of the wafer on the heating plate is generally high, so a relatively large electrostatic adsorption voltage is required to hold the wafer. The heating plate has a higher resistance at a higher temperature. When the wafer is desorbed, more residual charge is easily generated between the wafer and the heating plate, causing the wafer to break during desorption.

[0003] In traditional PECVD equipment, there are two methods to determine whether the desorption conditions are met: one is an indirect method, such as by detecting the capacitance between the wafer and the heating plate, or by detecting the change in the current flowing through the heating plate electrode; the other is a direct method, that is, by detecting the force when the wafer is lifted from the heating plate. The indirect method cannot directly detect the residual adsorption force, and the electrical signal used is easily interfered, so the judgment accuracy is not high; the direct method, such as using a torque meter to measure the force when lifting the wafer in real time, is mostly used in the configuration of movable ejector pins, and is large in size and not highly integrated. Summary of the invention

[0004] In order to overcome the defects of the prior art, the present invention provides a device and method for measuring the residual electrostatic adsorption force of a fixed ejector pin.

[0005] The device for measuring the residual electrostatic adsorption force of a fixed ejector pin of the present invention comprises a plurality of ejector pin support seats distributed circumferentially, a plurality of pressure sensors, a plurality of vacuum penetration pieces, a fixed bottom plate and a data processing module.

[0006] A pressure sensor is arranged at the upper end of each ejector support seat.

[0007] The lower end of each ejector support seat is fixed on the fixed bottom plate.

[0008] The upper end of each vacuum penetration piece is vacuum-tightly connected to one of the pressure sensors, and the lower end thereof penetrates through the fixed bottom plate and is connected to the data processing module.

[0009] The data processing module is configured to calculate the residual electrostatic adsorption force according to the signal transmitted by the pressure sensor and determine whether the wafer has the desorption condition.

[0010] In one embodiment, the device for measuring wafer eccentricity using a fixed ejector pin further comprises:

[0011] A base having a plurality of through holes;

[0012] A plurality of ejector pins, supporting the wafer placed on the base, wherein each of the ejector pins passes through one of the through holes, and the base can move up and down relative to the ejector pins;

[0013] A plurality of weights, each of which is sleeved on the outer periphery of the lower end portion of one of the ejector pins.

[0014] In one embodiment, when the lower end of the ejector pin falls to the upper end of the ejector pin support seat during the descending process, the ejector pin is supported by the ejector pin support seat and no longer moves downward. As the base moves downward, the ejector pin lifts the wafer, and the pressure sensor detects the pressure exerted on it.

[0015] In one embodiment, the upper end of the ejector pin contacts the wafer, and the lower end of the ejector pin is located directly above the ejector pin support seat.

[0016] In one embodiment, the outer diameter of the upper end of the ejector pin is greater than the minimum inner diameter of the through hole, so that the upper end of the ejector pin is stuck on the upper surface of the base.

[0017] In one embodiment, the number of the plurality of ejector pins corresponds to the number of the plurality of ejector pin support seats, the plurality of pressure sensors, and the plurality of vacuum penetration members.

[0018] In one embodiment, the pressure sensor is a piezoelectric ceramic pressure sensor.

[0019] In one embodiment, when the lower end of the ejector pin falls onto the upper end of the ejector pin support seat, the pressure sensor measures the amount of charge generated thereon, and the data processing module reads the amount of charge of each pressure sensor in real time, and obtains the corresponding residual electrostatic adsorption force F_d of each ejector pin according to the following formula:

[0020] F_d=(Q / d_33)-G;

[0021] in:

[0022] Q is the charge measured by one of the pressure sensors;

[0023] d_33 is the strain coefficient of the piezoelectric ceramic;

[0024] G is the sum of the weight of 1 / N wafer, the weight of one ejector pin and the weight of a heavy hammer, wherein N is the number of the ejector pin support seats.

[0025] In one embodiment, the data processing module calculates the stress σ_d generated by the residual electrostatic adsorption force in the wafer according to the residual electrostatic adsorption force F_d.

[0026] In one embodiment, the data processing module compares whether the stress σ_d is greater than a threshold value. If it is greater than the threshold value, it is determined that the wafer does not meet the desorption conditions and the lifting action of the ejector pin is stopped, wherein the threshold value is set to be less than the limit stress of the wafer material.

[0027] The present invention also provides a method for measuring the residual electrostatic adsorption force of a fixed ejector pin, the method is performed using the device for measuring the residual electrostatic adsorption force of a fixed ejector pin as described above, and the method includes but is not limited to the following steps:

[0028] When the lower end of the ejector pin falls onto the upper end of the ejector pin support seat, measuring the amount of charge generated on the pressure sensor;

[0029] The charge amount of each pressure sensor is read in real time, and the corresponding residual electrostatic adsorption force F_d of each ejector pin is obtained according to the charge amount:

[0030] Calculate the stress σ_d generated by the residual electrostatic adsorption force in the wafer according to the residual electrostatic adsorption force F_d;

[0031] Compare whether the stress σ_d is greater than a threshold value. If it is greater than the threshold value, it is determined that the wafer does not meet the desorption condition, and the lifting action of the ejector pin is stopped, wherein the threshold value is less than the limit stress of the wafer material.

[0032] In one embodiment, obtaining the corresponding residual electrostatic adsorption force F_d of each ejector pin according to the charge amount includes calculating the residual electrostatic adsorption force F_d according to the following formula:

[0033] F_d=(Q / d_33)-G;

[0034] in:

[0035] Q is the charge measured by one of the pressure sensors;

[0036] d_33 is the strain coefficient of the piezoelectric ceramic of the pressure sensor;

[0037] G is the sum of the weight of 1 / N wafer, the weight of one ejector pin and the weight of a heavy hammer, wherein N is the number of the ejector pin support seats.

[0038] The device and method for measuring residual electrostatic adsorption force of the present invention are suitable for fixed ejector pin configuration, using a piezoelectric ceramic (such as PZT-5A) pressure sensor, and fixed on the ejector pin support seat supporting the ejector pin, to detect the charge of the ejector pin when the wafer is lifted in real time. The data processing module calculates the stress generated by the residual electrostatic adsorption force inside the wafer, and determines whether the stress is greater than the fracture limit of the wafer, thereby determining whether the desorption conditions are met. Compared with the movable ejector pin structure, the device for measuring residual electrostatic adsorption force of the present invention is smaller in size and more integrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above invention content and the following specific embodiments of the present invention will be better understood when read in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are only examples of the claimed invention. In the accompanying drawings, the same reference numerals represent the same or similar elements.

[0040] Figure 1 A schematic diagram showing a device for measuring residual electrostatic adsorption force of a wafer for a fixed ejector pin according to an embodiment of the present invention;

[0041] Figure 2 A cross-sectional view showing a device for measuring residual electrostatic adsorption force of a wafer for a fixed ejector pin according to an embodiment of the present invention;

[0042] Figure 3 An enlarged cross-sectional view of an ejector pin support seat according to an embodiment of the present invention is shown;

[0043] Figure 4 An overall schematic diagram of a device for measuring residual electrostatic adsorption force of a wafer for a fixed ejector pin according to an embodiment of the present invention is shown;

[0044] Figure 5A , Figure 5B , Figure 5C Schematic diagrams showing different stages of the ejector pin descending according to an embodiment of the present invention are shown respectively. DETAILED DESCRIPTION

[0045] The detailed features and advantages of the present invention are described in detail in the specific embodiments below, and the content is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly, and according to the description, claims and drawings disclosed in this specification, those skilled in the art can easily understand the relevant purposes and advantages of the present invention. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0048] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, channels, components, regions, layers and / or parts, these components, channels, components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, channels, components, regions, layers and / or parts. In addition, the terms "first", "second", "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0049] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0050] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0051] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0052] Figure 1 A schematic diagram of a device for measuring the residual electrostatic adsorption force of a wafer for a fixed ejector according to an embodiment of the present invention is shown. The device includes a base 101, an ejector 102, a weight 103, an ejector support seat 104, a fixed bottom plate 105, a pressure sensor 106, a vacuum through piece ( Figure 1 Not shown, Figure 2 ), data processing module ( Figure 1 Not shown, Figure 4 ).

[0053] The base 101 is used to carry and heat the wafer 107. The base 101 has a plurality of through holes corresponding to the number of ejector pins.

[0054] In one embodiment, the base 101 is a heating plate.

[0055] The ejector pin 102 is inserted into the through hole. The outer diameter of the upper end of the ejector pin 102 is larger than the minimum inner diameter of the through hole, so that the upper end of the ejector pin 102 is stuck on the upper surface of the base 101 without falling.

[0056] The upper end of the ejector pin 102 supports the wafer placed on the susceptor 101 .

[0057] The weight 103 is sleeved on the outer periphery of the lower end of the ejector pin 102 .

[0058] The ejector pin support seat 104 is disposed below the ejector pin 102 and is used to support the ejector pin 102 .

[0059] The upper end of the ejector support seat 104 is fixed or integrated with a pressure sensor 106, and the lower end is fixed on the fixed bottom plate 105. When the base 101 drives the ejector 102 to descend, when the lower end of the ejector 102 falls to the upper end of the ejector support seat 104, the ejector 102 is held by the ejector support seat 104 and no longer moves downward. As the base 101 continues to move downward, the ejector 102 lifts the wafer 107, and the pressure sensor 106 can detect the pressure on it.

[0060] In one embodiment, the number of ejector pins is three, and the three ejector pins are evenly distributed along the circumferential direction.

[0061] In one embodiment, the pressure sensor 106 is a piezoelectric ceramic pressure sensor, which may be made of PZT-5A material. The advantage of piezoelectric ceramics is that they are highly sensitive and can induce more charges for a small deformation.

[0062] The pressure sensor 106 transmits the signal to a data processing module (not shown) for processing, so as to detect the amount of charge generated thereon (or the force applied thereon) in real time. The data processing module calculates the residual electrostatic adsorption force, and determines whether the stress generated inside the wafer by the residual electrostatic adsorption force is greater than a preset value, wherein the preset value is set to be less than the fracture limit (limit stress) of the wafer. If the stress is less than the preset value, it is determined that the wafer has the conditions for desorption. If the stress is greater than or equal to the preset value, it is considered that the wafer does not have the conditions for desorption, the ejector pin lifting action is stopped, and a system alarm is issued.

[0063] It should be pointed out that the desorption condition described in this article means that the stress generated inside the wafer when the ejector pin lifts the wafer is less than the fracture limit stress of the wafer.

[0064] In addition, the device for measuring the residual electrostatic adsorption force of a wafer of the present invention is preferably applied to a fixed ejector pin. Compared with a movable ejector pin structure, the device for measuring the residual electrostatic adsorption force of the present invention is smaller in size and has a higher degree of integration.

[0065] Figure 2 FIG. 2 is a cross-sectional view of a device for measuring residual electrostatic adsorption force of a fixed ejector pin according to an embodiment of the present invention. Figure 2 As shown, the ejector pin support seat 104 is located below the ejector pin 102. A pressure sensor 106 is integrated at the upper end of the ejector pin support seat 104, and the pressure sensor 106 transmits the measured signal to the data processing module through the vacuum penetration piece 201.

[0066] Figure 3FIG. 2 shows an enlarged cross-sectional view of an ejector support seat according to an embodiment of the present invention. The ejector support seat 104 is fixed on the fixed base plate 105. A pressure sensor 106 is provided at the upper end of the ejector support seat 104. The vacuum penetration member 201 has an upper end 301 and a lower end 302. The upper end 301 is sealed and connected to the pressure sensor 106, and the lower end 302 penetrates the fixed base plate 105 and is connected to an external data processing module through its cable.

[0067] The upper end 301 of the vacuum penetration piece 201 is connected to a high vacuum, and the lower end 302 is connected to the atmosphere. The vacuum penetration piece 201 is mainly used to introduce electrical signals into the high vacuum, while also maintaining a good seal.

[0068] Figure 4 FIG. 2 is a schematic diagram showing an overall structure of a device for measuring residual electrostatic adsorption force of a fixed ejector pin according to an embodiment of the present invention. Figure 4 As shown, the external data processing module is connected to the cable at the lower end of the vacuum feedthrough.

[0069] Figure 5A , Figure 5B , Figure 5C Schematic diagrams showing different stages of the ejector pin descending according to an embodiment of the present invention are shown respectively.

[0070] At the beginning, the ejector pin and the weight are separated from the ejector pin support seat. Figure 5A When the base (heating plate) moves downward, the ejector pin and the weight come into contact with the support seat, as shown in the figure. Figure 5B When the desorption conditions of the susceptor (heating plate) are met, the susceptor continues to move downward, and the wafer is lifted up by the ejector pins, as shown in FIG. Figure 5C As shown, at this time, the force applied to each pressure sensor (piezoelectric ceramic (such as PZT-5A) sensor) is the sum G of the weight of the 1 / N wafer, the weight of a pin and the weight of a heavy hammer.

[0071] It should be noted that N here represents the number of ejector pins or ejector pin support seats. When the desorption conditions are met, after the wafer is lifted up, the force applied to each pressure sensor is the sum G of 1 / N wafer weight, one ejector pin weight and one weight.

[0072] The following uses three ejector pins as an example to illustrate how to measure the residual electrostatic adsorption force and determine whether the desorption conditions are met.

[0073] When the wafer needs to be lifted, but the electrostatic adsorption force of the heating plate is not completely released, if there is residual charge, the force F1, F2, and F3 applied to the three piezoelectric ceramic (such as PZT-5A) pressure sensors are the sum G of 1 / 3 of the wafer weight, the weight of a pin, and the weight of a heavy hammer, and the residual electrostatic adsorption force F_d1, F_d2, and F_d3 corresponding to each pin. That is:

[0074] F1=G+F_d1;

[0075] F2=G+F_d2;

[0076] F3=G+F_d3.

[0077] For a piezoelectric ceramic (such as PZT-5A) pressure sensor, when a pressure F is applied, equal and opposite charges will be generated on the lower surface. The amount of charge is proportional to F, as follows:

[0078] Q=d_33*F

[0079] in:

[0080] Q is the charge, F is the pressure, and d_33 is the strain coefficient, an intrinsic characteristic of piezoelectric ceramics.

[0081] Therefore, the amount of charge output by each piezoelectric ceramic (such as PZT-5A) pressure sensor is:

[0082] Q1 = d_33*(G+F_d1);

[0083] Q2 = d_33*(G+F_d2);

[0084] Q3 = d_33*(G+F_d3);

[0085] The data processing module is connected to the vacuum feedthrough through a lead wire, and reads the charge of the three pressure sensors in real time, and infers the corresponding residual electrostatic adsorption forces F_d1, F_d2, and F_d3 of the three ejector pins:

[0086] F_d1=(Q1 / d_33)-G;

[0087] F_d2=(Q2 / d_33)-G;

[0088] F_d3=(Q3 / d_33)-G;

[0089] Where Q1, Q2, Q3 are the charges measured by each pressure sensor, d_33 is the strain coefficient of the piezoelectric ceramic, and G is the force applied to each pressure sensor, which is the sum of 1 / 3 of the wafer weight, a pin weight, and a heavy hammer weight.

[0090] The data processing module calculates the stress σ_d1, σ_d2, σ_d3 generated by the residual electrostatic adsorption force in the wafer based on the residual electrostatic adsorption force F_d1, F_d2, F_d3. When the stress σ_d1, σ_d2, σ_d3 generated by any residual electrostatic adsorption force F_d1, F_d2, F_d3 in the wafer is higher than the ultimate stress of the wafer material, the wafer will break; therefore, a threshold F_t can be set in the data processing module. When any residual electrostatic adsorption force F_d1, F_d2, F_d3 is greater than this threshold, it indicates that the wafer is at risk of breaking, the system alarms, and the ejection action of the ejector stops.

[0091] The present invention also provides a method for measuring the residual electrostatic adsorption force of a fixed ejector pin, the method is performed using the device for measuring the residual electrostatic adsorption force of a fixed ejector pin as described above, and the method includes but is not limited to the following steps:

[0092] When the lower end of the ejector pin falls onto the upper end of the ejector pin support seat, measuring the amount of charge generated on the pressure sensor;

[0093] The charge amount of each pressure sensor is read in real time, and the corresponding residual electrostatic adsorption force F_d of each ejector pin is obtained according to the charge amount:

[0094] Calculate the stress σ_d generated by the residual electrostatic adsorption force in the wafer according to the residual electrostatic adsorption force F_d;

[0095] Compare whether the stress σ_d is greater than a threshold value. If it is greater than the threshold value, it is determined that the wafer does not meet the desorption condition, and the lifting action of the ejector pin is stopped, wherein the threshold value is less than the limit stress of the wafer material.

[0096] In one embodiment, obtaining the residual electrostatic adsorption force F_d corresponding to each ejector pin according to the charge amount includes calculating the residual electrostatic adsorption force F_d according to the following formula (corresponding to each ejector pin, they are F_d1, F_d2, and F_d3 respectively):

[0097] F_d=(Q / d_33)-G;

[0098] in:

[0099] Q is the charge measured by one of the pressure sensors;

[0100] d_33 is the strain coefficient of the piezoelectric ceramic of the pressure sensor;

[0101] G is the sum of the weight of 1 / N wafer, the weight of one ejector pin and the weight of a heavy hammer, wherein N is the number of the ejector pin support seats.

[0102] Those skilled in the art will appreciate that the various illustrative components, modules, blocks, units, circuits, systems, and steps described in conjunction with the embodiments disclosed herein may be implemented by hardware, software (including firmware, resident software, microcode, etc.), or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, modules, blocks, units, circuits, systems, and steps are described above in general terms in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0103] Flowcharts are used in the present application to illustrate the operations or steps performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations or steps are not necessarily performed accurately in order. On the contrary, various operations or steps may be processed in reverse order or simultaneously. At the same time, other operations or steps may be added to these processes, or one or more operations or steps may be removed from these processes.

[0104] Unless explicitly stated in the claims, the order of the processing elements and sequences, the use of alphanumeric characters, or the use of other names described in the present application are not intended to limit the order of the processes and methods of the present application.

[0105] Furthermore, aspects of the present application may take the form of a computer product embodied in one or more computer-readable media including computer-readable program code.

[0106] A computer readable signal medium may include a propagated data signal containing computer program code, such as in baseband or as part of a carrier wave. The propagated signal may have a variety of forms, including electromagnetic, optical, etc., or a suitable combination. A computer readable signal medium may be any computer readable medium other than a computer readable storage medium, which may be connected to an instruction execution system, device or apparatus to communicate, propagate or transmit a program for use. The program code on the computer readable signal medium may be propagated through any suitable medium, including radio, cable, fiber optic cable, RF, or similar media, or any combination of the above media.

[0107] The computer program coding required for the operation of each part of the application can be written in any one or more programming languages, including object-oriented programming languages ​​such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python, etc., conventional procedural programming languages ​​such as C language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages ​​such as Python, Ruby and Groovy, or other programming languages, etc. The program coding can be run completely on the user's computer, or run on the user's computer as an independent software package, or run partly on the user's computer and partly on the remote computer, or run completely on the remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any network form, such as a local area network (LAN) or a wide area network (WAN), or connected to an external computer (e.g., via the Internet), or in a cloud computing environment, or used as a service such as software as a service (SaaS).

[0108] Those skilled in the art will appreciate that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0109] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be directly embodied in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. In an alternative, a processor and a storage medium may reside in a user terminal as discrete components.

[0110] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0111] The terms and expressions used above are for descriptive purposes only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean to exclude any equivalent features of the illustrations and descriptions (or parts thereof), and it should be recognized that various modifications that may exist should also be included in the scope of the claims. Other modifications, changes and substitutions may also exist. Accordingly, the claims should be deemed to cover all such equivalents.

[0112] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus facilitate the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, multiple features are sometimes combined into one embodiment, drawing or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims.

[0113] Similarly, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present invention, they will fall within the scope of the claims of this application.

Claims

1. A device for measuring residual electrostatic adsorption force, characterized in that: include: Multiple ejector support seats, multiple pressure sensors, multiple vacuum penetration parts, a fixed base plate and a data processing module distributed in the circumferential direction; A pressure sensor is disposed at the upper end of each ejector support seat; The lower end of each ejector support seat is fixed to the fixed bottom plate; The upper end of each vacuum penetration piece is vacuum-tightly connected to one of the pressure sensors, and the lower end thereof penetrates the fixed bottom plate and is connected to the data processing module; The data processing module is configured to calculate the residual electrostatic adsorption force according to the signal transmitted by the pressure sensor and determine whether the wafer has the desorption condition.

2. The device for measuring residual electrostatic adsorption force according to claim 1, characterized in that: Also includes: A base having a plurality of through holes; A plurality of ejector pins, supporting the wafer placed on the base, wherein each of the ejector pins passes through one of the through holes, and the base can move up and down relative to the ejector pins; A plurality of weights, each of which is sleeved on the outer periphery of the lower end portion of one of the ejector pins.

3. The device for measuring residual electrostatic adsorption force according to claim 2, characterized in that: When the lower end of the ejector pin falls to the upper end of the ejector pin support seat during the descending process, the ejector pin is supported by the ejector pin support seat and no longer moves downward. As the base moves downward, the ejector pin lifts the wafer, and the pressure sensor detects the pressure exerted on it.

4. The device for measuring residual electrostatic adsorption force according to claim 2, characterized in that: The upper end of the ejector pin contacts the wafer, and the lower end of the ejector pin is located directly above the ejector pin supporting seat.

5. The device for measuring residual electrostatic adsorption force according to claim 2, characterized in that: The outer diameter of the upper end of the ejector pin is greater than the minimum inner diameter of the through hole, so that the upper end of the ejector pin is stuck on the upper surface of the base.

6. The device for measuring residual electrostatic adsorption force according to claim 2, characterized in that: The number of the plurality of ejector pins corresponds to the number of the plurality of ejector pin support seats, the plurality of pressure sensors, and the plurality of vacuum penetration pieces.

7. The device for measuring residual electrostatic adsorption force according to claim 1, characterized in that: The pressure sensor is a piezoelectric ceramic pressure sensor.

8. The device for measuring residual electrostatic adsorption force according to claim 7, characterized in that: When the lower end of the ejector pin falls onto the upper end of the ejector pin support seat, the pressure sensor measures the amount of charge generated thereon, and the data processing module reads the amount of charge of each pressure sensor in real time, and obtains the corresponding residual electrostatic adsorption force F_d of each ejector pin according to the following formula: F_d=(Q / d_33)-G; in: Q is the charge measured by one of the pressure sensors; d_33 is the strain coefficient of the piezoelectric ceramic; G is the sum of the weight of 1 / N wafer, the weight of one ejector pin and the weight of a heavy hammer, wherein N is the number of the ejector pin support seats.

9. The device for measuring residual electrostatic adsorption force according to claim 8, characterized in that: The data processing module calculates the stress σ_d generated by the residual electrostatic adsorption force in the wafer according to the residual electrostatic adsorption force F_d.

10. The device for measuring residual electrostatic adsorption force according to claim 9, characterized in that: The data processing module compares whether the stress σ_d is greater than a threshold value. If it is greater than the threshold value, it is determined that the wafer does not meet the desorption conditions and the lifting action of the ejector pin is stopped, wherein the threshold value is set to be less than the ultimate stress of the wafer material.

11. A method for measuring residual electrostatic adsorption force, characterized in that: The method is performed using the device for measuring residual electrostatic adsorption force of a fixed ejector according to claim 1, and the method comprises: When the lower end of the ejector pin falls onto the upper end of the ejector pin support seat, measuring the amount of charge generated on the pressure sensor; The charge amount of each pressure sensor is read in real time, and the corresponding residual electrostatic adsorption force F_d of each ejector pin is obtained according to the charge amount: Calculate the stress σ_d generated by the residual electrostatic adsorption force in the wafer according to the residual electrostatic adsorption force F_d; Compare whether the stress σ_d is greater than a threshold value. If it is greater than the threshold value, it is determined that the wafer does not meet the desorption conditions, and the lifting action of the ejector pin is stopped, wherein the threshold value is set to be less than the ultimate stress of the wafer material.

12. The method for measuring residual electrostatic adsorption force according to claim 11, characterized in that: Obtaining the corresponding residual electrostatic adsorption force F_d of each ejector pin according to the charge amount includes calculating the residual electrostatic adsorption force F_d according to the following formula: F_d=(Q / d_33)-G; in: Q is the charge measured by one of the pressure sensors; d_33 is the strain coefficient of the piezoelectric ceramic of the pressure sensor; G is the sum of the weight of 1 / N wafer, the weight of one ejector pin and the weight of a heavy hammer, wherein N is the number of the ejector pin support seats.

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