Wafer displacement identification method, device, equipment, medium and product

Abstract

The invention provides a wafer displacement identification method and device, equipment, a medium and a product, and the method comprises the steps: constructing a plane coordinate system through a plane where a to-be-detected wafer is located, and obtaining a first length value collected by a first capacitive sensor and a second length value collected by a second capacitive sensor; acquiring a first standard position coordinate of the first capacitive sensor on the plane coordinate system and a second standard position coordinate of the second capacitive sensor on the plane coordinate system; and according to the first length value, the second length value, the first standard position coordinate and the second standard position coordinate, calculating the offset from the actual circle center of the wafer to be measured to the original point. According to the method, the offset distance of the actual circle center of the wafer to be measured in the horizontal plane direction can be accurately calculated by designing the layout mode of the coplanar capacitive sensors, the method has low requirements for light conditions, contact with the wafer is not needed, the recognition accuracy is further improved, and the wafer breakage rate is reduced.

Description

Technical Field

[0001] The present invention relates to the field of wafer transfer technology, and in particular to a wafer shift identification method, device, equipment, medium and product. Background Art

[0002] The wafer transfer robot is the core part of the wafer conveying system. The wafer transfer robot can accurately sense the position, posture and state of the wafer, and realize the transfer of wafers between different stations through autonomous grasping, handling and placement operations, as well as the accurate positioning of the wafer. During the grasping process, if the wafer slips on the robot, it will cause the edge of the wafer to wear or even the entire wafer to break. When the wafer is transported to the next station, if the wafer is not positioned accurately, it will cause operation failure, such as inaccurate cutting. It can be seen that accurate positioning of the wafer is crucial.

[0003] In the prior art, optical sensors or contact sensors are installed on the robot to determine whether the wafer is shifted. Optical sensors are easily affected by ambient light, resulting in inaccurate final judgment results. Contact sensors need to be in direct contact with the wafer, which may contaminate or even damage the wafer, affecting product quality.

[0004] It can be seen that the existing wafer shift identification methods are either prone to inaccurate identification or easily cause contamination to the wafer. Summary of the invention

[0005] The present invention provides a wafer shift identification method, device, equipment, medium and product, which are used to solve the defects in the prior art that optical sensors have strict requirements on ambient light and are prone to inaccurate wafer positioning, or that contact sensors are prone to contamination of wafers, and to accurately identify wafer shift without contacting the wafer.

[0006] The present invention provides a wafer shift identification method, comprising the following steps.

[0007] A plane coordinate system is constructed with the plane where the wafer to be tested is located, wherein the coordinate origin of the plane coordinate system is the arc center of the hand fork of the manipulator; the central axis of the hand fork of the manipulator is the horizontal axis, and the vertical line perpendicular to the central axis and passing through the origin is the vertical axis; Acquire a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor respectively; wherein the first length value is a capacitance length change in a radial direction where the first capacitance sensor is located; the second length value is a capacitance length change in a radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances; Acquire a first standard position coordinate of the first capacitive sensor on the plane coordinate system, and a second standard position coordinate of the second capacitive sensor on the plane coordinate system; The offset of the actual center of the wafer to be measured from the origin is calculated according to the first length value, the second length value, the first standard position coordinates, and the second standard position coordinates.

[0008] According to a wafer shift identification method provided by the present invention, the calculation of the offset of the actual center of the wafer to be measured from the origin according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate includes: Calculate the horizontal coordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate; Calculate the ordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate; The distance between the actual center of the wafer to be measured and the origin is calculated according to the abscissa and the ordinate of the actual center of the wafer to be measured, and the distance is used as the offset of the actual center of the wafer to be measured.

[0009] According to a wafer shift identification method provided by the present invention, the coordinates of the first standard position of the first capacitive sensor are the coordinates of the first intersection between the edge of the wafer to be measured at the standard position and the radial direction of the center of the first capacitive sensor; The coordinates of the second standard position of the second capacitive sensor are the coordinates of the second intersection point between the edge of the wafer to be measured at the standard position and the radial direction of the center of the second capacitive sensor; The standard position is the position of the wafer to be tested when the center of the wafer to be tested coincides with the center of the arc of the hand fork of the robot.

[0010] The present invention also provides a wafer shift identification method, comprising the following steps: Determining a dielectric constant in a third capacitive sensor; wherein a distance between two electrodes of the third capacitive sensor is within a preset range; Before the robot grabs the wafer to be tested, obtaining a first height value collected by the third capacitive sensor; Calculating a deviation between the first height value and a preset standard height value; If the deviation is within the preset error range, it is determined that the position of the wafer to be tested is normal.

[0011] According to a wafer shift identification method provided by the present invention, the dielectric constant is preset according to the material type of the wafer to be tested.

[0012] The present invention also provides a wafer shift identification device, comprising the following modules: A plane coordinate system construction module is used to construct a plane coordinate system based on the plane where the wafer to be tested is located, wherein the coordinate origin of the plane coordinate system is the arc center of the hand fork of the manipulator; the central axis of the hand fork of the manipulator is used as the horizontal axis, and the vertical line perpendicular to the central axis and passing through the origin is used as the vertical axis; A length value measurement module, used to respectively obtain a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor; wherein the first length value is a capacitance length change in a radial direction where the first capacitance sensor is located; the second length value is a capacitance length change in a radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances; A sensor position acquisition module, used to acquire a first standard position coordinate of the first capacitive sensor on the plane coordinate system, and a second standard position coordinate of the second capacitive sensor on the plane coordinate system; The wafer offset calculation module is used to calculate the offset of the actual center of the wafer to be measured from the origin according to the first length value, the second length value, the first standard position coordinates, and the second standard position coordinates.

[0013] The present invention also provides a wafer shift identification device, comprising the following modules: A dielectric constant determination module, used to determine the dielectric constant of a third capacitive sensor; wherein the distance between two electrodes of the third capacitive sensor is within a preset range; A first height value acquisition module, used for acquiring a first height value collected by the third capacitive sensor before the robot grabs the wafer to be tested; A deviation calculation module, used for calculating the deviation between the first height value and a preset standard height value; The position determination module is used to determine that the position of the wafer to be tested is normal if the deviation is within a preset error range.

[0014] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, any one of the wafer shift identification methods described above is implemented.

[0015] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the wafer shift identification method as described in any one of the above is implemented.

[0016] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned wafer shift identification methods.

[0017] The wafer shift identification method, device, equipment, medium and product provided by the present invention are as follows: a plane coordinate system is constructed with the plane where the wafer to be tested is located, and the coordinate origin of the plane coordinate system is the arc center of the hand fork arc of the manipulator; the central axis of the hand fork of the manipulator is used as the horizontal axis, and the vertical line perpendicular to the central axis and passing through the origin is used as the vertical axis; a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor are respectively obtained; wherein the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances; the first standard position coordinates of the first capacitance sensor on the plane coordinate system and the second standard position coordinates of the second capacitance sensor on the plane coordinate system are obtained; according to the first length value, the second length value, and the first standard position coordinates and the second standard position coordinates, the offset of the actual center of the wafer to be tested from the origin is calculated. This method can accurately calculate the offset distance of the actual center of the wafer to be tested in the horizontal direction by designing the position layout of the coplanar capacitive sensors, which is conducive to the robot adjusting the position of the wafer to be tested to avoid the occurrence of wafer wear or breakage. It is also conducive to accurate positioning of the wafer and provides favorable conditions for subsequent operation steps. Compared with traditional optical sensors and contact sensors, this method has lower requirements on light conditions and does not require contact with the wafer, which further improves the recognition accuracy and reduces the wafer damage rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The figure is a simplified structural diagram of the wafer transfer robot provided by the present invention.

[0020] Figure 2This is one of the flow charts of the wafer shift identification method provided by the present invention.

[0021] Figure 3 This is one of the structural schematic diagrams of the wafer transfer robot viewed downward along the Z axis.

[0022] Figure 4 This is the second structural diagram of the wafer transfer robot viewed downward along the Z axis.

[0023] Figure 5 This is the second flow chart of the wafer shift identification method provided by the present invention.

[0024] Figure 6 It is a schematic diagram of the positions of the robot arm and the wafer in the vertical direction provided by the present invention.

[0025] Figure 7 This is the third flow chart of the wafer shift identification method provided by the present invention.

[0026] Figure 8 This is one of the structural schematic diagrams of the flat-plate capacitor provided by the present invention.

[0027] Fig. 9 This is the second structural schematic diagram of the flat-plate capacitor provided by the present invention.

[0028] Fig.10 It is a structural schematic diagram of the interdigital capacitor provided by the present invention.

[0029] Fig.11 It is a schematic diagram of the circuit structure of the capacitor provided by the present invention.

[0030] Fig.12 This is one of the structural schematic diagrams of the wafer shift identification device provided by the present invention.

[0031] Fig.13 This is the second structural schematic diagram of the wafer shift identification device provided by the present invention.

[0032] Fig.14 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Combine the following Figure 1-Figure 14Specific embodiments of the present invention are described.

[0035] like Figure 1 As shown, Figure 1 The schematic diagram of the structure of the wafer transfer robot is shown. The robot targeted by this application is an R-θ three-degree-of-freedom robot, which includes the freedom of up and down movement along the Z axis, the freedom of θ rotation movement around the Z axis, and the freedom of telescopic movement along the radial direction R of the robot. The wafer shift identification method provided in this application is only for the above-mentioned freedom of up and down movement along the Z axis and the freedom of telescopic movement along the radial direction R of the robot.

[0036] Figure 2 It is one of the flow charts of the wafer shift identification method provided by the present invention, such as Figure 2 As shown, the method is mainly used to detect whether the wafer slips on the robot hand fork. If slipping, it may cause uneven force on the wafer and cause edge wear or wafer breakage. The method includes the following steps.

[0037] Step 201, construct a plane coordinate system with the plane where the wafer to be tested is located, the coordinate origin of the plane coordinate system is the arc center of the hand fork of the robot; the central axis of the hand fork of the robot is the horizontal axis, and the vertical axis is the vertical line perpendicular to the central axis and passing through the origin.

[0038] like Figure 3 As shown, Figure 3 The schematic diagram of the robot structure when looking down along the Z axis is shown. First, the plane coordinate system OXY is determined, and the plane coordinate system OXY is constructed with the plane where the wafer to be measured is located, wherein the origin O of the plane coordinate system is the arc center of the robot's hand fork (hereinafter referred to as the hand fork center point); the central axis of the robot's hand fork is the horizontal axis (ie, the X-axis), and the vertical line perpendicular to the central axis and passing through the origin is the vertical axis (ie, the Y-axis).

[0039] Step 202: Obtain the first length value collected by the first capacitive sensor A respectively and the second length value collected by the second capacitive sensor B ; wherein, the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances.

[0040] Among them, Figure 3As shown, the first capacitance sensor A and the second capacitance sensor B are respectively installed on the hand fork of the wafer transfer robot, and are used to measure the relative movement of the wafer on the horizontal plane. For example, when the capacitance value of the first capacitance sensor A increases, it means that the wafer moves to the upper left; when the capacitance value of the first capacitance sensor A decreases, it means that the wafer moves to the lower right; when the capacitance value of the second capacitance sensor B increases, it means that the wafer moves to the lower left; when the capacitance value of the second capacitance sensor B decreases, it means that the wafer moves to the upper right.

[0041] The capacitors in the first capacitive sensor A and the second capacitive sensor B are both coplanar capacitors. Coplanar capacitors are capacitors that are realized by transverse electromagnetic coupling between coplanar electrodes, and the two electrodes are coplanar. For example, a coplanar capacitor can be a fork-finger capacitor; the two capacitive sensors adopt a rectangular structure, and the central axis parallel to the long side is extended to intersect at the above-mentioned coordinate origin O (i.e., the center point of the hand fork). On the one hand, the coplanar capacitive sensor can reduce the vertical height of the capacitive sensor, making it easier to install the sensor on the hand fork (fingers) of the wafer transfer robot; on the other hand, it is convenient to arrange the shielding electrode between the two capacitive poles to reduce the influence of the fringe electric field between the electrodes on the measurement results.

[0042] The first capacitive sensor A and the second capacitive sensor B are installed on the arc of the hand fork. The two can be symmetrically distributed with the X-axis as the symmetry axis, or they can be asymmetrically distributed. However, it must be ensured that when the center of the wafer coincides with the center O of the hand fork, the long sides of the two sensors are blocked by 1 / 2 of the wafer, so that when the wafer slides, the change in capacitance value is within the linear range (because the width of the rectangular capacitive sensor is small enough relative to the diameter of the wafer to be measured, it can be approximately considered that the change in capacitance value of the capacitive sensor is greatly affected by the factor of being blocked by the wafer in the long axis direction, and the capacitance change caused by the short side is ignored).

[0043] When the wafer to be tested slides on the horizontal plane (i.e., the OXY plane), the change in capacitance generated by the first capacitance sensor A and the second capacitance sensor B changes linearly with the length of the electrode being blocked. The lengths of the two capacitance sensors blocked by the wafer to be tested are calculated based on the change in capacitance. (i.e. the first length value) and (i.e. the second length value).

[0044] Step 203: Obtain the first standard position coordinates of the first capacitive sensor A in the plane coordinate system , and, the second standard position coordinates of the second capacitive sensor B on the plane coordinate system .

[0045] Specifically, the first standard position coordinates of the first capacitive sensor A on the plane coordinate system are That is, its ideal installation position, that is, when the wafer is in the standard position (that is, the position when the center of the wafer coincides with the center of the arc of the hand fork), the edge of the wafer and the theoretical installation position of the first capacitive sensor (that is, the central axis parallel to the long side of the capacitive sensor passes through the center O of the hand fork) in the radial direction (that is, the diameter direction passing through point O) Intersection, this is a theoretical value, which can be obtained by prior calculation and stored in the memory, and can be directly called when needed.

[0046] like Figure 4 As shown, Figure 4 The schematic diagram of the actual position of the wafer to be measured is shown. The following content explains the measurement principle and method of the actual position of the wafer.

[0047] The theoretical position of the center of the wafer to be tested is point O When the robot completes the acquisition of the wafer to be tested, the actual center of the wafer to be tested is located at Point C is The foot of the perpendicular on line AO.

[0048] Define the vector in the direction of the linear AO , , , ;but.

[0049] ; (1) ; (2) The above vector , , Substituting into equations (1) and (2) we obtain: ; (3) ; (4) Defining Line Segments Length for.

[0050] ; (5) Then the line segment Projection length in the direction of line AO for.

[0051] ; (6) Similarly, line segment Projection length in the direction of line BO for.

[0052] ; (7) It should be noted that the line segment Projection length in the direction of line AO In fact, it is the displacement of the actual center of the wafer to be measured in the radial direction of the first capacitance sensor, that is, the blocked increment or exposed increment (collectively referred to as capacitance change) of the first capacitance sensor caused by the movement of the wafer, which can be measured by the first capacitance sensor; similarly, the line segment Projection length in the direction of line BO In fact, it is the component of the displacement of the actual center of the wafer to be measured in the radial direction of the second capacitance sensor, that is, the obscured increment or exposed increment (collectively referred to as capacitance change) of the second capacitance sensor caused by the movement of the wafer, which can be measured by the second capacitance sensor.

[0053] Therefore, in the equations constructed by the above formulas (6) and (7), we need to find the unknown and , then we can find the line segment Length , according to formulas (6) and (7), we can get

[0054] ; (8) ; (9) Finally, the line segment can be obtained according to the above formula (5): Length , that is, the offset of the actual center of the wafer to be tested.

[0055] According to the above formulas (8) and (9), as long as the first standard position coordinates of the first capacitive sensor A on the plane coordinate system are measured, , the second standard position coordinates of the second capacitive sensor B on the plane coordinate system , and the length change of the first capacitive sensor A due to wafer movement , the length change of the first capacitive sensor B caused by the movement of the wafer , then we can find and , and then we can get the line segment Length , that is, the actual center offset of the wafer to be tested .

[0056] Step 204: according to the first length value The second length value , and the first standard position coordinates , the second standard position coordinates , calculate the offset of the actual center of the wafer to be tested from the origin .

[0057] Specifically, as described above, the first length value The second length value , and the first standard position coordinates , the second standard position coordinates , substituting into formula (8) and (9) to obtain and ; Then, according to formula (5), we can obtain the line segment Length , that is, the offset of the actual center of the wafer to be tested.

[0058] In the above embodiment, a plane coordinate system is constructed with the plane where the wafer to be tested is located, and the coordinate origin of the plane coordinate system is the arc center of the fork arc of the manipulator; the central axis of the fork of the manipulator is the horizontal axis, and the vertical line perpendicular to the central axis through the origin is the vertical axis; the first length value collected by the first capacitance sensor and the second length value collected by the second capacitance sensor are respectively obtained; wherein the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located; the first standard position coordinate of the first capacitance sensor on the plane coordinate system and the second standard position coordinate of the second capacitance sensor on the plane coordinate system are obtained; according to the first length value, the second length value, and the first standard position coordinate and the second standard position coordinate, the offset of the actual center of the wafer to be tested from the origin is calculated. The method can accurately calculate the offset distance of the actual center of the wafer to be tested in the horizontal plane direction by designing the position local mode of the coplanar capacitance sensor, which is beneficial for the manipulator to adjust the position of the wafer to be tested, avoid the occurrence of wafer wear or breakage, and also beneficial for accurate wafer positioning, providing favorable conditions for subsequent operation steps. Compared with traditional optical sensors and contact sensors, this method has lower requirements on light conditions and does not require contact with the wafer, which further improves recognition accuracy and reduces wafer damage rate.

[0059] In one embodiment, the above-mentioned step 204 includes: calculating the horizontal coordinate of the actual center of the wafer to be measured in the plane coordinate system according to the first length value, the second length value, and the first standard position coordinate and the second standard position coordinate; calculating the vertical coordinate of the actual center of the wafer to be measured in the plane coordinate system according to the first length value, the second length value, and the first standard position coordinate and the second standard position coordinate; calculating the distance between the actual center of the wafer to be measured and the origin according to the horizontal coordinate and the vertical coordinate of the actual center of the wafer to be measured, and taking the distance as the offset of the actual center.

[0060] Specifically, the actual center offset is calculated according to the above formulas (8), (9) and (5), which will not be described in detail here.

[0061] In the above embodiment, the actual center offset is calculated by the pre-derived formula, which can not only determine whether the wafer is offset, but also accurately calculate the offset of the wafer to be tested, which is conducive to the subsequent precise adjustment of the wafer position.

[0062] In one embodiment, the coordinates of the first standard position of the first capacitive sensor are the coordinates of the first intersection between the edge of the wafer to be measured at the standard position and the radial direction of the center of the first capacitive sensor; the first intersection can ensure that the capacitance of the first capacitive sensor is just partially blocked; the coordinates of the second standard position of the second capacitive sensor are the coordinates of the second intersection between the edge of the wafer to be measured at the standard position and the radial direction of the center of the second capacitive sensor.

[0063] The first intersection can ensure that the capacitance of the first capacitance sensor is partially blocked, so that when the wafer moves slightly on the hand fork, the blocked portion of the capacitance will change synchronously, so that the displacement of the wafer can be finally calculated based on the change in capacitance. Preferably, the second intersection can ensure that the capacitance of the first capacitance sensor is just blocked by half; wherein the standard position is the position of the wafer to be tested when the center of the wafer to be tested coincides with the center of the arc of the hand fork of the manipulator.

[0064] The above embodiment provides a necessary basis for subsequent measurement of wafer offset by laying out the installation positions of the second capacitive sensor of the first capacitive sensor.

[0065] like Figure 5 As shown, accurate wafer positioning is ensured by detecting in the horizontal direction.

[0066] In one embodiment, the present application also provides a wafer displacement identification method for identifying the position offset of a wafer in the vertical direction (i.e., the Z-axis direction). This method can be used in combination with the above-mentioned wafer displacement identification method in the horizontal plane direction, or can be used alone, or can be used in combination with other methods. The method comprises the following steps: Step 501, initializing the wafer transfer robot device.

[0067] Step 502: The robot arm takes the wafer from the Foup and lifts the wafer to a height where it can exit the Foup.

[0068] Step 503, the robot carries the wafer out of the Foup. During this process, the capacitance sensors A and B are used to monitor the changes in the capacitance values ​​of each sensor in real time, so as to determine the position change between the wafer and the hand fork and whether the wafer is slipping on the hand fork.

[0069] The specific judgment process is as described above and will not be repeated here.

[0070] Step 504, if there is no relative movement between the wafer and the hand fork, the robot completes the normal wafer picking action; if there is relative movement, an alarm message is sent to the management end, and the robot slows down until it stops.

[0071] The above embodiment, by applying the above wafer shift recognition method, can quickly and accurately detect the relative movement of the wafer on the hand fork, thereby reducing the wafer breakage rate.

[0072] like Figure 6 As shown, Figure 6 The schematic diagram of the position of the wafer and the manipulator in the vertical direction is shown. When the manipulator moves vertically, the distance the manipulator moves from the lower surface of the wafer in the vertical direction is measured by the change in the value of the third capacitance sensor. For example, the distance the manipulator moves from the lower surface of the wafer in the vertical direction can be calculated by the change in the value of the third capacitance sensor (calculating the distance between the third capacitance sensor and the lower surface of the wafer). When the value of the third capacitance sensor increases, it means that the distance between the wafer and the sensor is decreasing and the manipulator is moving upward; when the value of the third capacitance sensor decreases, it means that the distance between the wafer and the sensor is decreasing and the manipulator is moving downward. Since the position of the manipulator in the Foup (FrontOpening Unified Pod or Front Opening Universal Pod, front-opening wafer transfer box) is different, in order to ensure the accuracy of the vertical measurement, the sensor for vertical measurement cannot be reused with the sensor for horizontal measurement. When measuring in the vertical direction, the sensor needs to be installed as close to the center of the wafer as possible to ensure that the capacitance sensor is fully covered by the wafer during each lifting process.

[0073] like Figure 7 As shown, Figure 7 The second flow chart of the wafer shift identification method provided in the present application is shown, and the method includes:

[0074] Step 701, determining the dielectric constant of a third capacitive sensor; wherein two electrodes of the third capacitive sensor are arranged in a coplanar structure.

[0075] Specifically, a capacitive sensor that can adapt to a variety of wafer materials such as glass, silicon, germanium, gallium arsenide, silicon nitride, etc. can be designed, and different dielectric constants can be set for wafers of different materials, and the corresponding dielectric constants can be calibrated. Establish a dielectric constant database in the memory, use different dielectric constants to correct the data for wafer materials in different processes, and obtain the dielectric constant corresponding to the silicon wafer when the wafer to be tested is determined to be a silicon wafer. This can improve the accuracy of the measurement results, thereby enhancing the adaptability of the sensor to different materials and reducing the deviation of the measurement results caused by different materials.

[0076] The electrode layout of the third capacitive sensor adopts a coplanar electrode layout structure, that is, the two electrodes of the capacitor are coplanar or approximately coplanar (that is, the two capacitors are divided into two layers, the spacing between the two layers is less than 0.1mm). Generally, capacitor electrode 1 is a driving electrode, and capacitor electrode 2 is a sensing electrode. Generally, the distance between the driving electrode and the sensing electrode is 0.5mm~3mm. This application adopts planar capacitor electrodes. The third capacitive sensor is any one of a parallel plate capacitor or a finger capacitor. Among them, the structural schematic diagram of the parallel plate capacitor is as shown in Figure 8 or Fig. 9 As shown, the structural diagram of the interdigital capacitor is as follows Fig.10 As shown, in the interdigital capacitor, λ is the interdigital period (the distance between electrodes with the same potential), ω is the interdigital width of the interdigital capacitor, g is the interdigital gap, and l is the interdigital length.

[0077] There may or may not be a shielding electrode between the capacitor electrode 1 and the capacitor electrode 2. It is better to use a shielding electrode to reduce the influence of the edge electric field between the electrodes on the measurement results. The bottom of the sensor is composed of a protective layer, an electrode layer, a base layer, a shielding layer, a protective layer, etc. from top to bottom. The electrode layer can be divided into a driving electrode layer and a sensing electrode layer. The two layers can overlap on the same plane or be distributed on adjacent planes with a spacing of less than 0.1 mm.

[0078] The capacitance value between the two electrodes of a single planar capacitance sensor is very small, often in the pF level. The capacitance change caused by the mass change of the object to be measured is even smaller, so it is necessary to design a tiny capacitance detection circuit.

[0079] like Fig.11 As shown, the sine signal generator generates the excitation signal Capacitor to be tested The excitation then passes through the detector, outputting an AC voltage , then yes.

[0080] ; (10) like , then the above formula can be expressed as.

[0081] ; (11) in, is the excitation signal, is the capacitance to be measured, is the reference capacitor, the output AC voltage value With the capacitor to be tested Directly proportional.

[0082] The AC excitation capacitance detection circuit uses AC excitation and AC amplifier, which can effectively reduce the impact of charge injection effect and has high measurement accuracy. In parallel with the excitation signal, stray capacitance Connected to the inverting input of the operational amplifier, neither will have any effect on the output AC voltage.

[0083] Step 702: before the robot grabs the wafer to be tested, obtain a first height value collected by the third capacitive sensor.

[0084] Specifically, before the robot grabs the wafer to be tested, the third capacitive sensor measures the distance between the current robot and the lower surface of the wafer, that is, the first height value. The measurement principle is shown in the above formulas (10)-(11).

[0085] Step 703: Calculate the deviation between the first height value and a preset standard height value.

[0086] Specifically, the preset standard height value is the ideal position of the wafer. In order to determine whether the current wafer is suitable for being clamped, the difference between the current distance and the ideal distance needs to be calculated.

[0087] Step 704: If the deviation is within a preset error range, it is determined that the position of the wafer to be tested is normal.

[0088] Specifically, if the deviation is within a preset error range, the position of the wafer to be tested is judged to be normal, and the robot arm rises to perform subsequent wafer picking operations. If it is abnormal, the hand fork exits Foup and an alarm is sounded.

[0089] In the above embodiment, the dielectric constant in the third capacitance sensor is determined; wherein the spacing between the two electrodes of the third capacitance sensor is within a preset range; before the manipulator grabs the wafer to be tested, the first height value collected by the third capacitance sensor is obtained; the deviation between the first height value and the preset standard height value is calculated; if the deviation is within the preset error range, the position of the wafer to be tested is judged to be normal. This method can adapt to wafers of different material categories, accurately identify the position of the wafer in the vertical direction, effectively solve problems such as wafer sliding and inaccurate positioning, improve production efficiency and product quality, and meet the needs of this field.

[0090] The wafer shift identification device provided by the present invention is described below. The wafer shift identification device described below and the wafer shift identification method described above can be referred to each other.

[0091] like Fig.12 As shown, Fig.12 A wafer shift identification device is demonstrated, including the following modules: The plane coordinate system construction module 1201 is used to construct a plane coordinate system based on the plane where the wafer to be tested is located. The coordinate origin of the plane coordinate system is the center of the arc of the manipulator's hand fork; the central axis of the manipulator's hand fork is the horizontal axis, and the vertical axis is the vertical line perpendicular to the central axis and passing through the origin.

[0092] The length value measuring module 1202 is used to respectively obtain a first length value collected by the first capacitance sensor and a second length value collected by the second capacitance sensor; wherein the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; and the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located.

[0093] The sensor position acquisition module 1203 is used to acquire the first standard position coordinates of the first capacitive sensor in the plane coordinate system and the second standard position coordinates of the second capacitive sensor in the plane coordinate system.

[0094] The wafer offset calculation module 1204 is used to calculate the offset of the actual center of the wafer to be measured from the origin according to the first length value, the second length value, the first standard position coordinates, and the second standard position coordinates.

[0095] In one embodiment, the wafer offset calculation module 1204 is further used to: calculate the horizontal coordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate; calculate the vertical coordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, and the first standard position coordinate, and the second standard position coordinate; calculate the distance between the actual center of the wafer to be measured and the origin according to the horizontal coordinate and the vertical coordinate of the actual center of the wafer to be measured, and use the distance as the offset of the actual center.

[0096] In one embodiment, the coordinates of the first standard position of the first capacitive sensor are the coordinates of a first intersection point between an edge of the wafer to be measured at the standard position and a radial direction where a center of the first capacitive sensor is located.

[0097] The coordinates of the second standard position of the second capacitive sensor are the coordinates of a second intersection point between the edge of the wafer to be measured at the standard position and the radial direction of the center of the second capacitive sensor.

[0098] The first intersection can ensure that a portion of the capacitance of the first capacitance sensor is blocked, so that when the wafer moves slightly on the fork, the blocked portion of the capacitance will change synchronously, so that the displacement of the wafer can be finally calculated based on the change in capacitance. Preferably, the second intersection can ensure that half of the capacitance of the first capacitance sensor is blocked.

[0099] The standard position is the position of the wafer to be tested when the center of the wafer to be tested coincides with the center of the arc of the hand fork of the robot.

[0100] like Fig.13 As shown, Fig.13 A wafer shift identification device is presented, comprising the following modules.

[0101] The dielectric constant determination module 1301 is used to determine the dielectric constant of the third capacitive sensor; wherein the distance between two electrodes of the third capacitive sensor is within a preset range.

[0102] The first height value acquisition module 1302 is used to acquire the first height value collected by the third capacitive sensor before the robot grabs the wafer to be tested.

[0103] The deviation calculation module 1303 is used to calculate the deviation between the first height value and a preset standard height value.

[0104] The position determination module 1304 is configured to determine that the position of the wafer to be tested is normal if the deviation is within a preset error range.

[0105] In one embodiment, the dielectric constant is preset according to the material type of the wafer to be tested.

[0106] Fig.14 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8As shown, the electronic device may include: a processor (processor) 1410 , a communication interface (Communications Interface) 1420 , a memory (memory) 1430 and a communication bus 1440 , wherein the processor 1410 , the communication interface 1420 , and the memory 1430 communicate with each other through the communication bus 1440 . The processor 1410 can call the logic instructions in the memory 1430 to execute the wafer shift identification method, which includes: constructing a plane coordinate system with the plane where the wafer to be tested is located, and the coordinate origin of the plane coordinate system is the arc center of the manipulator's hand fork arc; taking the central axis of the manipulator's hand fork as the horizontal axis, and taking the vertical line perpendicular to the central axis and passing through the origin as the vertical axis; respectively obtaining a first length value collected by the first capacitance sensor and a second length value collected by the second capacitance sensor; wherein the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located; obtaining the first standard position coordinates of the first capacitance sensor in the plane coordinate system, and the second standard position coordinates of the second capacitance sensor in the plane coordinate system; according to the first length value, the second length value, and the first standard position coordinates and the second standard position coordinates, calculating the offset of the actual center of the wafer to be tested from the origin. And / or, the following wafer shift identification method includes: determining the dielectric constant in the third capacitance sensor; wherein the spacing between the two electrodes of the third capacitance sensor is within a preset range; before the robot grasps the wafer to be tested, obtaining a first height value collected by the third capacitance sensor; calculating the deviation between the first height value and a preset standard height value; if the deviation is within a preset error range, determining that the position of the wafer to be tested is normal.

[0107] In addition, the logic instructions in the above-mentioned memory 1430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk.

[0108] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the wafer shift identification method provided by the above methods, which method includes: constructing a plane coordinate system with the plane where the wafer to be tested is located, and the coordinate origin of the plane coordinate system is the arc center of the manipulator's hand fork arc; taking the central axis of the manipulator's hand fork as the horizontal axis, and taking the vertical line perpendicular to the central axis and passing through the origin as the vertical axis; respectively obtaining a first length value collected by a first capacitive sensor and a second length value collected by a second capacitive sensor; wherein the first length value is the capacitance length change in the radial direction where the first capacitive sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitive sensor is located; obtaining the first standard position coordinates of the first capacitive sensor in the plane coordinate system, and the second standard position coordinates of the second capacitive sensor in the plane coordinate system; according to the first length value, the second length value, and the first standard position coordinates and the second standard position coordinates, calculating the offset of the actual center of the wafer to be tested from the origin. And / or, the following wafer shift identification method includes: determining the dielectric constant in the third capacitance sensor; wherein the spacing between the two electrodes of the third capacitance sensor is within a preset range; before the robot grasps the wafer to be tested, obtaining a first height value collected by the third capacitance sensor; calculating the deviation between the first height value and a preset standard height value; if the deviation is within a preset error range, determining that the position of the wafer to be tested is normal.

[0109] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the wafer shift identification method provided by the above-mentioned methods, the method comprising: constructing a plane coordinate system with the plane where the wafer to be measured is located, the coordinate origin of the plane coordinate system being the arc center of the hand fork arc of the manipulator; taking the central axis of the hand fork of the manipulator as the horizontal axis, and taking the vertical line perpendicular to the central axis and passing through the origin as the vertical axis; respectively obtaining a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor; wherein the first length value is the capacitance length change in the radial direction where the first capacitance sensor is located; the second length value is the capacitance length change in the radial direction where the second capacitance sensor is located; obtaining the first standard position coordinates of the first capacitance sensor in the plane coordinate system, and the second standard position coordinates of the second capacitance sensor in the plane coordinate system; and calculating the offset of the actual center of the wafer to be measured from the origin based on the first length value, the second length value, and the first standard position coordinates and the second standard position coordinates. And / or, the following wafer shift identification method includes: determining the dielectric constant in the third capacitance sensor; wherein the spacing between the two electrodes of the third capacitance sensor is within a preset range; before the robot grasps the wafer to be tested, obtaining a first height value collected by the third capacitance sensor; calculating the deviation between the first height value and a preset standard height value; if the deviation is within a preset error range, determining that the position of the wafer to be tested is normal.

[0110] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0111] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer shift identification method, characterized in that: include: A plane coordinate system is constructed with the plane where the wafer to be tested is located, and the origin of the plane coordinate system is the arc center of the hand fork arc of the manipulator; The central axis of the hand fork of the manipulator is taken as the horizontal axis, and the vertical line perpendicular to the central axis and passing through the origin is taken as the vertical axis; Acquire a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor respectively; wherein the first length value is a capacitance length change in a radial direction where the first capacitance sensor is located; the second length value is a capacitance length change in a radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances; Acquire a first standard position coordinate of the first capacitive sensor on the plane coordinate system, and a second standard position coordinate of the second capacitive sensor on the plane coordinate system; The offset of the actual center of the wafer to be measured from the origin is calculated according to the first length value, the second length value, the first standard position coordinates, and the second standard position coordinates.

2. The wafer shift identification method according to claim 1, characterized in that: The calculating, according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate, to obtain the offset of the actual center of the wafer to be measured from the origin includes: Calculate the horizontal coordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate; Calculate the ordinate of the actual center of the wafer to be measured on the plane coordinate system according to the first length value, the second length value, the first standard position coordinate, and the second standard position coordinate; The distance between the actual center of the wafer to be measured and the origin is calculated according to the abscissa and the ordinate of the actual center of the wafer to be measured, and the distance is used as the offset of the actual center of the wafer to be measured.

3. The wafer shift identification method according to claim 1, characterized in that: The coordinates of the first standard position of the first capacitive sensor are the coordinates of the first intersection between the edge of the wafer to be measured at the standard position and the radial direction of the center of the first capacitive sensor; The coordinates of the second standard position of the second capacitive sensor are the coordinates of the second intersection point between the edge of the wafer to be measured at the standard position and the radial direction of the center of the second capacitive sensor; The standard position is the position of the wafer to be tested when the center of the wafer to be tested coincides with the center of the arc of the hand fork of the robot.

4. A wafer shift identification method, characterized in that: include: Determining a dielectric constant in a third capacitive sensor; wherein a distance between two electrodes of the third capacitive sensor is within a preset range; Before the robot grabs the wafer to be tested, obtaining a first height value collected by the third capacitive sensor; Calculating a deviation between the first height value and a preset standard height value; If the deviation is within the preset error range, it is determined that the position of the wafer to be tested is normal.

5. The wafer shift identification method according to claim 4, characterized in that: The dielectric constant is preset according to the material type of the wafer to be tested.

6. A wafer shift identification device, characterized in that: include: A plane coordinate system construction module is used to construct a plane coordinate system based on the plane where the wafer to be measured is located, wherein the coordinate origin of the plane coordinate system is the arc center of the hand fork arc of the manipulator; The central axis of the hand fork of the manipulator is taken as the horizontal axis, and the vertical line perpendicular to the central axis and passing through the origin is taken as the vertical axis; A length value measurement module, used to respectively obtain a first length value collected by a first capacitance sensor and a second length value collected by a second capacitance sensor; wherein the first length value is a capacitance length change in a radial direction where the first capacitance sensor is located; the second length value is a capacitance length change in a radial direction where the second capacitance sensor is located; the capacitance in the first capacitance sensor and the capacitance in the second capacitance sensor are both coplanar capacitances; A sensor position acquisition module, used to acquire a first standard position coordinate of the first capacitive sensor on the plane coordinate system, and a second standard position coordinate of the second capacitive sensor on the plane coordinate system; The wafer offset calculation module is used to calculate the offset of the actual center of the wafer to be measured from the origin according to the first length value, the second length value, the first standard position coordinates, and the second standard position coordinates.

7. A wafer shift identification device, characterized in that: include: A dielectric constant determination module, used to determine the dielectric constant of a third capacitive sensor; wherein the distance between two electrodes of the third capacitive sensor is within a preset range; A first height value acquisition module, used for acquiring a first height value collected by the third capacitive sensor before the robot grabs the wafer to be tested; A deviation calculation module, used for calculating the deviation between the first height value and a preset standard height value; The position determination module is used to determine that the position of the wafer to be tested is normal if the deviation is within a preset error range.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the wafer shift identification method according to any one of claims 1 to 5 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the wafer shift identification method according to any one of claims 1 to 5 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the wafer shift identification method according to any one of claims 1 to 5 is implemented.

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