Reflector flatness detection method, device and system

Abstract

The invention discloses a reflector flatness detection method, device and system, and relates to the technical field of flatness detection. The reflector flatness detection method comprises the following steps: selecting a plurality of target bare chip units arranged along a first direction from a wafer placed on a motion platform; the motion platform is controlled to move along the target straight line, a laser beam is emitted to the strip-shaped reflector through the laser interferometer, and measurement position information of all reflector areas of the strip-shaped reflector in the second direction is measured one by one; performing linear fitting on the arrangement sequence of each reflector area in the first direction and the measurement position information in the second direction to obtain a target fitting function; the difference between the measurement position information of each reflector area and the corresponding theoretical position information on the target fitting function is obtained, and the measurement deviation corresponding to each reflector area is obtained; and determining the flatness of the strip-shaped reflector according to the measurement deviation corresponding to each reflector area.

Description

Technical Field

[0001] The present application belongs to the technical field of flatness detection, and in particular, relates to a method, device and system for detecting the flatness of a reflector. Background Art

[0002] In the chip manufacturing process, the measurement of key dimensions is an important part of ensuring product yield. When measuring key dimensions, it mainly relies on the laser interferometer to emit a laser beam to the reflector, and the wafer is accurately positioned based on the laser beam fed back by the reflector. However, the flatness error of the reflector will interfere with the precise positioning of the wafer, so the flatness of the reflector needs to be tested.

[0003] In the existing method, the flatness of the reflector is mainly detected by a detector for detecting the flatness of mechanical parts.

[0004] However, the measuring accuracy of the detector is only at the sub-micron level, which results in low detection accuracy of the flatness of the reflector. Summary of the invention

[0005] The embodiments of the present application provide a method, device and system for detecting the flatness of a reflector, which can improve the detection accuracy of the flatness of the reflector.

[0006] In one aspect of an embodiment of the present application, a method for detecting the flatness of a reflector is provided, comprising:

[0007] Selecting a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform, the wafer comprising regularly arranged bare die units, and the moving platform is equipped with a strip-shaped reflector arranged along the first direction;

[0008] Controlling the motion platform to move along the target straight line, using a laser interferometer to emit a laser beam to the strip reflector, measuring the measurement position information of each reflector area of ​​the strip reflector in the second direction one by one, the first direction is perpendicular to the second direction, the target straight line is a straight line where a plurality of target bare chip units are located, and the reflector area corresponds to the target bare chip unit one by one;

[0009] Performing linear fitting on the order in which each reflector region is arranged in the first direction and the measured position information in the second direction to obtain a target fitting function;

[0010] Subtract the measured position information of each reflector area from the corresponding theoretical position information on the target fitting function to obtain the measurement deviation corresponding to each reflector area;

[0011] The flatness of the strip reflector is determined based on the measured deviations corresponding to each reflector area.

[0012] In one aspect of an embodiment of the present application, a device for detecting the flatness of a reflector is provided, comprising:

[0013] A unit selection module is used to select a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform, the wafer comprising regularly arranged bare die units, and a strip-shaped reflector arranged along the first direction is installed on the moving platform;

[0014] A position measurement module is used to control the motion platform to move along a target straight line, emit a laser beam to the strip reflector by using a laser interferometer, and measure the measurement position information of each reflector area of ​​the strip reflector in a second direction one by one, wherein the first direction is perpendicular to the second direction, the target straight line is a straight line where a plurality of target bare chip units are located, and the reflector area corresponds to the target bare chip unit one by one;

[0015] A function fitting module, used for performing linear fitting on the order of arrangement of each reflector region in the first direction and the measurement position information in the second direction to obtain a target fitting function;

[0016] A deviation determination module is used to subtract the measured position information of each reflector area from the corresponding theoretical position information on the target fitting function to obtain the measurement deviation corresponding to each reflector area;

[0017] The flatness determination module is used to determine the flatness of the strip reflector according to the measurement deviation corresponding to each reflector area.

[0018] In one aspect of an embodiment of the present application, a system for detecting the flatness of a reflector is provided, comprising a motion platform, a scanning electron microscope, a laser interferometer, a strip reflector, a photodetector, and a controller;

[0019] A motion platform is connected to the controller and is used to move the wafer placed on the motion platform along the direction of the target straight line in response to a movement instruction of the controller;

[0020] A scanning electron microscope is connected to the controller and is used to respond to the recognition instruction of the controller and recognize whether the motion platform deviates from the direction of the target straight line when the controller controls the motion platform to move along the direction of the target straight line;

[0021] A laser interferometer, connected to the controller, for emitting a laser beam toward the strip-shaped reflector in response to a detection instruction of the controller;

[0022] The strip reflector is installed on the motion platform and connected to the photodetector to receive the laser beam sent by the laser interferometer and feed back the laser beam to the photodetector;

[0023] A photoelectric detector is connected to the strip reflector and the controller, and is used to determine the measurement position information of the reflector area of ​​the strip reflector in the second direction according to the laser beam fed back by the strip reflector, and send the measurement position information to the controller;

[0024] A controller is used to execute the method for detecting the flatness of a reflector provided in any aspect of the above-mentioned embodiments of the present application.

[0025] In one aspect of an embodiment of the present application, an electronic device is provided, which includes: a memory and a program or instruction stored in the memory and executable on a processor, wherein when the program or instruction is executed by the processor, a method for detecting the flatness of a reflector provided in any aspect of the above-mentioned embodiment of the present application is implemented.

[0026] In one aspect of an embodiment of the present application, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, a method for detecting the flatness of a reflector provided in any aspect of the above-mentioned embodiment of the present application is implemented.

[0027] In one aspect of an embodiment of the present application, a computer program product is provided. When instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes a method for detecting the flatness of a reflector provided in any aspect of the above-mentioned embodiment of the present application.

[0028] In the detection method of the flatness of the reflector provided in the embodiment of the present application, by selecting a plurality of target bare chip units arranged along the first direction and located on the target straight line in the wafer, an ideal straight line is selected as a reference on the wafer with nanometer-level precision in the process. Thus, the motion platform can be controlled to move accurately along the first direction according to the target straight line to avoid the motion platform from offsetting during the movement. In the case where the motion platform moves accurately along the first direction, the strip reflector installed on the motion platform will also move accurately along the first direction. At this time, the measurement position information of each reflector area corresponding to the target bare chip unit in the strip reflector in the second direction will remain the same in principle. Thus, according to the change of the measurement position information of each reflector area in the second direction, the flatness of the strip reflector can be accurately obtained. In this way, the embodiment of the present application can realize the accurate movement of the motion platform and the strip reflector in the first direction by selecting an ideal straight line arranged along the first direction on the wafer as the reference line, thereby improving the detection accuracy of the flatness of the reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 It is a schematic flow chart of a method for detecting the flatness of a reflector provided in one embodiment of the present application;

[0031] Figure 2 is a schematic diagram of the flatness of a strip reflector provided by an embodiment of the present application;

[0032] Figure 3 is a schematic diagram of selecting a target bare chip unit provided by an embodiment of the present application;

[0033] Figure 4 It is a structural schematic diagram of a device for detecting the flatness of a reflector provided in one embodiment of the present application;

[0034] Figure 5 It is a schematic diagram of the structure of a device for detecting the flatness of a reflector provided in one embodiment of the present application. DETAILED DESCRIPTION

[0035] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0037] It should be noted that the acquisition, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of national laws and regulations.

[0038] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned, and they should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0039] In the related art, the flatness of the reflector is mainly detected by a detector for detecting the flatness of mechanical parts. However, the measurement accuracy of the detector is only sub-micron level, resulting in low detection accuracy of the flatness of the reflector.

[0040] The purpose of the present application is to provide a method, device and system for detecting the flatness of a reflector. In the method for detecting the flatness of a reflector provided in the embodiment of the present application, by selecting a plurality of target bare chip units arranged along a first direction in a wafer and located on a target straight line, an ideal straight line is selected on a wafer with a process of nanometer precision as a reference. Thus, the motion platform can be controlled to move accurately along the first direction according to the target straight line to avoid the motion platform from being offset during the movement. In the case where the motion platform moves accurately along the first direction, the strip reflector mounted on the motion platform will also move accurately along the first direction. At this time, the measurement position information of each reflector area corresponding to the target bare chip unit in the strip reflector in the second direction will remain the same in principle. Thus, according to the change of the measurement position information of each reflector area in the second direction, the flatness of the strip reflector can be accurately obtained. In this way, the embodiment of the present application can realize the accurate movement of the motion platform and the strip reflector in the first direction by selecting an ideal straight line arranged along the first direction on the wafer as a reference line, thereby improving the detection accuracy of the flatness of the reflector. The following describes the specific embodiments of the method, device and system for detecting the flatness of the reflector provided in the embodiments of the present application. First, the method for detecting the flatness of the reflector is described.

[0041] Figure 1 A schematic flow chart of a method for detecting the flatness of a reflector is provided. The method for detecting the flatness of a reflector can be applied to a controller of a system for detecting the flatness of a reflector. The method for detecting the flatness of a reflector can include the following steps S101 to S105.

[0042] S101, selecting a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform, the wafer comprising regularly arranged bare die units, and a strip-shaped reflector arranged along the first direction is installed on the moving platform.

[0043] In this embodiment, the first direction is a preset direction for selecting the target bare chip unit. For example, the first direction can be along the X-axis direction or along the Y-axis direction. The X-axis is perpendicular to the Y-axis, and the plane formed by the two is parallel to the wafer surface. In addition, the motion platform can move linearly along the X-axis and can also move linearly along the Y-axis.

[0044] The strip reflector is installed on the edge of the moving platform and arranged in a first direction. For example, the length direction of the strip reflector can be arranged along the X-axis direction, or along the Y-axis direction.

[0045] As an example, Figure 2 As shown, the controller selects a plurality of target bare die units located in a straight line along the X-axis direction from the bare die units regularly arranged in the wafer placed on the motion platform.

[0046] Specifically, multiple target die units may be randomly selected in a straight line, or multiple target die units may be selected in a straight line according to a preset selection rule. For example, the preset selection rule may be to select a target die unit every other die unit.

[0047] S102, according to each target bare chip unit, control the motion platform to move along the target straight line, use the laser interferometer to emit a laser beam to the strip reflector, and measure the measurement position information of each reflector area of ​​the strip reflector in the second direction one by one, the first direction is perpendicular to the second direction, the target straight line is the straight line where multiple target bare chip units are located, and the reflector area corresponds to the target bare chip unit one by one.

[0048] In this embodiment, the measured position information is position information measured by a laser interferometer, specifically, the measured distance between the laser interferometer and each reflector region of the strip reflector in the second direction.

[0049] The second direction is a direction perpendicular to the first direction. For example, when the first direction is the X-axis direction, the second direction is the Y-axis direction; when the first direction is the Y-axis direction, the second direction is the X-axis direction.

[0050] The strip reflector includes multiple reflector areas, and the position information of each reflector area in the first direction is the same as the position information of the corresponding target bare chip unit in the first direction, and the serial number of each reflector area in the first direction is also the same as the serial number of the corresponding target bare chip unit in the first direction.

[0051] As an example, Figure 2As shown, when the first direction is the X-axis direction, the controller controls the motion platform to move along the target straight line where the target bare chip unit is located, and then uses the laser interferometer to emit a laser beam to the strip reflector arranged along the X-axis direction, and measures the measurement position information of each reflector area corresponding to the target bare chip unit in the strip reflector in the second direction one by one according to the laser beam fed back by the strip reflector.

[0052] As another example, as shown in Table 1 below, a data table of measurement position information of each reflector region in the strip reflector in the X-axis direction is provided when the first direction is the Y-axis direction.

[0053] Table 1 Data table of measurement position information of each reflector area in the strip reflector in the X-axis direction

[0054]

[0055] S103, performing linear fitting on the arrangement order of each reflector region in the first direction and the measured position information in the second direction to obtain a target fitting function.

[0056] In this embodiment, the target fitting function is a linear function obtained by performing linear fitting on the measurement position information corresponding to each reflector region.

[0057] As an example, the controller fits a linear function according to the arrangement order of each reflector region in the X-axis direction and the measured position information of each reflector region in the Y-axis direction.

[0058] As another example, the controller may perform linear fitting on the measured position information of each reflector region in the X-axis direction in Table 1 above, so as to obtain a corresponding linear function: y=-0.000002x+0.0004.

[0059] S104, subtracting the measured position information of each reflector region from the corresponding theoretical position information on the target fitting function to obtain the measurement deviation corresponding to each reflector region.

[0060] In this embodiment, the theoretical position information is the position information corresponding to the reflector region on the target fitting function.

[0061] As an example, for each reflector area corresponding to each target bare die unit on the target straight line, the controller calculates the theoretical position information corresponding to the target fitting function, and then calculates the difference between the theoretical position information of each reflector area and the measured position information of the corresponding reflector area.

[0062] As another example, when the controller obtains the target fitting function as: y=-0.000002x+0.0004, the controller performs a difference calculation on the measured position information in Table 1 above and the theoretical position information on the corresponding target fitting function, and a measurement deviation data table of each reflector area in the strip reflector as shown in Table 2 below can be obtained.

[0063] Table 2 Measurement deviation data table of each reflector area in the strip reflector

[0064]

[0065] S105, determining the flatness of the strip-shaped reflector according to the measurement deviation corresponding to each reflector region.

[0066] In this embodiment, as an example, the controller may regard the measurement deviation corresponding to each reflector area as the flatness error of the corresponding position of the strip reflector.

[0067] As another example, the controller may determine the difference between the maximum deviation and the minimum deviation in the measured deviations corresponding to each reflector region as the flatness of the strip reflector.

[0068] like Figure 3 According to the measurement deviation data table of each reflector area in the strip reflector shown in Table 2, it can be drawn to obtain Figure 3 Schematic diagram of the flatness of the strip reflector shown in FIG. Figure 3 It can be seen that the difference between the maximum value of the measured deviation data and the minimum value of the measured deviation data is 837 nm, that is, the flatness of the strip reflector is 837 nm.

[0069] Through this embodiment, multiple target bare chip units arranged along the first direction and located on the target straight line are selected in the wafer, and an ideal straight line is selected as a reference on the wafer with nanometer-level precision in the process. Therefore, the motion platform can be controlled to move accurately along the first direction according to the target straight line to avoid the motion platform from offsetting during the movement. When the motion platform moves accurately along the first direction, the strip reflector installed on the motion platform will also move accurately along the first direction. At this time, the measurement position information of each reflector area corresponding to the target bare chip unit in the strip reflector in the second direction will remain the same in principle. Therefore, according to the change of the measurement position information of each reflector area in the second direction, the flatness of the strip reflector can be accurately obtained. In this way, the embodiment of the present application can realize the accurate movement of the motion platform and the strip reflector in the first direction by selecting an ideal straight line arranged along the first direction on the wafer as the reference line, thereby improving the detection accuracy of the reflector flatness.

[0070] As an optional embodiment, S101 may specifically include:

[0071] acquiring a wafer image of a wafer placed on a motion platform;

[0072] Based on the wafer image, a plurality of target bare die units arranged along a first direction are selected from the wafer placed on the moving platform.

[0073] In this embodiment, the wafer image is an image representing the surface features of the wafer.

[0074] As an example, the controller uses an electron beam to scan the surface of a wafer placed on the moving platform to obtain a wafer image of the wafer placed on the moving platform, and then selects a plurality of target bare die units arranged along a first direction from the wafer placed on the moving platform according to the wafer image.

[0075] Through this embodiment, a wafer image of a wafer placed on a moving platform is obtained, and then a plurality of target bare die units arranged along a first direction are selected from the wafer using the wafer image. By obtaining the wafer image, the surface features of the wafer can be intuitively obtained, which helps to select a suitable target bare die unit, and further an ideal straight line can be obtained as a reference line, thereby improving the detection accuracy of the flatness of the reflector.

[0076] As an optional embodiment, based on the wafer image, selecting a plurality of target bare die units arranged along the first direction from the wafer placed on the moving platform may specifically include:

[0077] Based on the wafer image, a central bare die unit corresponding to the center of a circle in the wafer placed on the motion platform is obtained;

[0078] Extending from the central bare die unit toward the first direction, a plurality of target bare die units in the wafer placed on the moving platform are selected.

[0079] In this embodiment, the central die unit is a die unit corresponding to the center of the wafer.

[0080] As an example, Figure 2 As shown, a schematic diagram of selecting a target bare die unit is provided. The controller determines the position of the center of the circle in the wafer according to the wafer image of the wafer placed on the motion platform, and then determines that the bare die unit marked with a solid center is the central bare die unit according to the position of the center of the circle.

[0081] Then, when the first direction is the X-axis direction, after determining the central bare chip unit, the controller extends to both ends along the X-axis direction, and determines each bare chip unit on the same straight line with the central bare chip unit as the target bare chip unit, thereby obtaining the target straight line as the diameter passing through the center of the circle.

[0082] After obtaining each target bare chip unit, the controller controls the motion platform to move along the target straight line where the target bare chip unit is located, and then uses the laser interferometer to emit a laser beam to the strip reflector set along the X-axis direction. According to the laser beam fed back by the strip reflector, the measurement position information of each reflector area of ​​the strip reflector in the Y-axis direction can be measured one by one.

[0083] Through this embodiment, the central die unit corresponding to the center of the wafer is obtained, and multiple target die units on the wafer diameter are extended from the central die unit to the first direction. In this way, the embodiment of the present application can ensure that the reflector flatness of each position of the strip reflector can be detected by selecting multiple target die units on the wafer diameter, avoiding detecting only the reflector flatness of a part of the strip reflector, and improving the overall detection accuracy of the reflector flatness.

[0084] As an optional embodiment, based on the wafer image, obtaining the central bare die unit corresponding to the center of the circle of the wafer placed on the moving platform may specifically include:

[0085] Selecting at least three wafer edge points that are not on the same straight line from the wafer edge of the wafer in the wafer image;

[0086] Determine the center position of the wafer placed on the motion platform according to at least three wafer edge points;

[0087] The die unit corresponding to the center position of the wafer is determined as the central die unit.

[0088] In this embodiment, the controller obtains at least three wafer edge points on the wafer edge of the wafer in the wafer image that are not on the same straight line based on the wafer image. Then, the center position of the wafer is calculated based on the at least three wafer edge points. Finally, the die unit where the center position of the wafer is located is determined as the central die unit.

[0089] Through this embodiment, at least three wafer edge points that are not on the same straight line are selected from the wafer edge of the wafer in the wafer image, and then the center position of the wafer can be determined based on the wafer edge points, thereby determining the central bare die unit. In this way, the embodiment of the present application can accurately obtain the center position of the wafer based on at least three wafer edge points on the wafer edge, thereby facilitating the subsequent selection of the target bare die unit on the wafer diameter and improving the overall detection accuracy of the reflector flatness.

[0090] As an optional embodiment, extending from the central bare die unit toward the first direction and selecting a plurality of target bare die units in the wafer placed on the moving platform may specifically include:

[0091] Extending from the central die unit in a first direction to obtain a target straight line;

[0092] Each bare die unit on a target straight line in a wafer placed on the moving platform is determined as a target bare die unit.

[0093] In this embodiment, after determining the central die unit, the controller extends the die unit toward both ends along the first direction to obtain the corresponding diameter in the wafer, and determines the diameter as the target straight line. Finally, each die unit corresponding to the target straight line is determined as the target die unit.

[0094] Through this embodiment, each bare die unit corresponding to the diameter is determined as a target bare die unit, so that the flatness of the reflector at each position of the strip reflector can be detected, avoiding detecting only the flatness of the reflector at a part of the strip reflector, and improving the overall detection accuracy of the reflector flatness. As an optional embodiment, S102 may specifically include:

[0095] The following steps are executed repeatedly until each target die unit on the target line is traversed:

[0096] Control the motion platform to move along the direction of the target straight line until the preset detection point of the i-th target bare chip unit on the target straight line is located at the target position of the field of view of the scanning electron microscope, and the initial value of i is 1;

[0097] Using a laser interferometer to emit a laser beam along the strip-shaped reflector, measuring the measurement position information of the reflector area of ​​the strip-shaped reflector corresponding to the i-th target die unit in the second direction;

[0098] Determine whether i is less than N, where N is the number of target die units;

[0099] When i is less than N, i is updated to i+1.

[0100] In this embodiment, the field of view target position is a position in the field of view corresponding to a preset scanning electron microscope, and is used to identify whether the motion platform deviates from the direction of the target straight line. For example, the field of view target position may be the center position of the field of view of the scanning electron microscope.

[0101] The preset detection point is a preset measurement reference point of the target bare die unit.

[0102] As an example, the controller controls the motion platform to move along the target straight line until the preset detection point of the first target bare die unit on the target straight line is located at the target position of the field of view of the scanning electron microscope. Then, a laser interferometer is used to emit a laser beam to the strip reflector arranged along the first direction, and based on the laser beam fed back by the strip reflector, the measurement position information of the reflector area of ​​the strip reflector corresponding to the first target bare die unit in the second direction is measured.

[0103] Then, it is determined whether each target die unit on the target straight line has been traversed. If each target die unit on the target straight line has not been traversed, the controller controls the motion platform to continue to move along the direction of the target straight line until the preset detection point of the next target die unit on the target straight line is located at the target position of the field of view of the scanning electron microscope. Then, a laser interferometer is used to emit a laser beam to the strip reflector arranged along the first direction, and according to the laser beam fed back by the strip reflector, the measurement position information of the reflector area of ​​the strip reflector corresponding to the next target die unit in the second direction is measured.

[0104] When all target die units on the target straight line are traversed, the measurement of the measurement position information of the target die units in the second direction is terminated.

[0105] Through this embodiment, starting from the first target die unit, the measurement position information of the reflector area of ​​the strip reflector corresponding to each target die unit in the second direction is measured cyclically to avoid missing the target die unit. At the same time, a scanning electron microscope is used to identify whether the motion platform deviates from the direction of the first straight line. In this way, the embodiment of the present application can obtain more accurate measurement position information of the reflector area of ​​the strip reflector corresponding to each target die unit in the second direction by traversing the measurement position information of the reflector area of ​​the strip reflector corresponding to each target die unit and using a scanning electron microscope to identify whether the motion platform deviates from the direction of the target straight line, thereby improving the detection accuracy of the reflector flatness.

[0106] As an optional embodiment, the preset detection point of the target die unit is at least one point on the target detection edge of the target die unit, and the target detection edge is the edge of the target die unit that is closest to the diameter of the wafer along the first direction.

[0107] In this embodiment, as an example, when the first direction is the X-axis direction and the center of the wafer is in the upper half of the central die unit, it indicates that the line formed by the upper vertices of the target die unit is closer to the length of the diameter. At this time, the upper left vertex of the target die unit and / or the upper right vertex of the target die unit are used as preset detection points of the target die unit.

[0108] When the first direction is the X-axis direction and the center of the wafer is in the lower half of the central die unit, it indicates that the line formed by the lower vertices of the target die unit is closer to the length of the diameter. At this time, the lower left vertex of the target die unit and / or the lower right vertex of the target die unit are used as preset detection points of the target die unit.

[0109] When the first direction is the Y-axis direction and the center of the wafer is in the left half of the central die unit, it indicates that the line formed by the left vertex of the target die unit is closer to the length of the diameter. At this time, the upper left vertex of the target die unit and / or the lower left vertex of the target die unit are used as preset detection points of the target die unit.

[0110] When the first direction is the Y-axis direction and the center of the wafer is in the right half of the central die unit, it indicates that the line formed by the right vertex of the target die unit is closer to the length of the diameter. At this time, the upper right vertex of the target die unit and / or the lower right vertex of the target die unit are used as preset detection points of the target die unit.

[0111] Through this embodiment, according to the type of the first direction and the center position of the wafer, a suitable preset detection point is selected, which can ensure that the connection line formed by each preset detection point can be close to the diameter length, so that the reflector flatness of each position of the strip reflector can be detected, avoiding detecting only the reflector flatness of a part of the strip reflector, and improving the overall detection accuracy of the reflector flatness.

[0112] As an optional embodiment, S105 may specifically include:

[0113] The measurement deviations corresponding to the reflector regions are sorted in order of magnitude to obtain a measurement deviation sequence;

[0114] Obtain the first measurement deviation and the last measurement deviation in the measurement deviation sequence;

[0115] The flatness of the strip reflector is obtained by subtracting the first measured deviation from the last measured deviation.

[0116] In this embodiment, the controller first arranges the measurement deviations corresponding to the reflector regions in descending order to obtain a measurement deviation sequence. Then, the first measurement deviation and the last measurement deviation in the measurement deviation sequence are obtained, that is, the maximum value and the minimum value of the measurement deviation are obtained, and the last measurement deviation is subtracted from the first measurement deviation to obtain the flatness of the strip reflector.

[0117] Through this embodiment, the measurement deviations corresponding to each reflector area are first sorted in order of size, thereby obtaining a measurement deviation sequence. Then, the maximum value of the measurement deviation and the minimum value of the measurement deviation can be obtained according to the measurement deviation sequence, and the minimum value of the measurement deviation is subtracted from the maximum value of the measurement deviation to obtain the flatness of the strip reflector. In this way, by analyzing the measurement deviations corresponding to each reflector area in the strip reflector, the flatness of the strip reflector can be accurately obtained, thereby improving the recognition accuracy of the reflector flatness.

[0118] Based on the detection method of the flatness of the reflector. Accordingly, the present application also provides a specific embodiment of the detection system of the flatness of the reflector.

[0119] The reflector flatness detection system provided in the embodiment of the present application includes a motion platform, a scanning electron microscope, a laser interferometer, a strip reflector, a photoelectric detector and a controller;

[0120] A motion platform is connected to the controller and is used to move the wafer placed on the motion platform along the direction of the target straight line in response to a movement instruction of the controller;

[0121] A scanning electron microscope is connected to the controller and is used to respond to the recognition instruction of the controller and recognize whether the motion platform deviates from the direction of the target straight line when the controller controls the motion platform to move along the direction of the target straight line;

[0122] A laser interferometer, connected to the controller, for emitting a laser beam toward the strip-shaped reflector in response to a detection instruction of the controller;

[0123] The strip reflector is installed on the motion platform and connected to the photodetector to receive the laser beam sent by the laser interferometer and feed back the laser beam to the photodetector;

[0124] A photoelectric detector connected to the strip reflector and the controller, and used to determine the measurement position information of the reflector area of ​​the strip reflector in the second direction according to the laser beam fed back by the strip reflector, and send the measurement position information to the controller;

[0125] A controller is used to execute any one of the above methods for detecting the flatness of a reflector.

[0126] In this embodiment, when the controller detects the flatness of the reflector, it first sends a movement instruction to the motion platform and sends an identification instruction to the scanning electron microscope. The motion platform responds to the movement instruction of the controller and moves the wafer placed on the motion platform along the direction of the target straight line. At the same time, the scanning electron microscope responds to the identification instruction of the controller and identifies whether the motion platform deviates from the direction of the target straight line.

[0127] When the SEM identifies that the preset detection point of the target die unit in the wafer on the motion platform is located at the target position of the field of view of the SEM, a stop command is sent to the controller. The controller receives the stop command sent by the SEM and sends the stop command to the motion platform to stop the motion of the motion platform.

[0128] Then, the controller sends a detection instruction to the laser interferometer. In response to the detection instruction of the controller, the laser interferometer sends a laser beam to the strip reflector. The strip reflector receives the laser beam sent by the laser interferometer and feeds the laser beam back to the photodetector.

[0129] The photoelectric detector determines the measurement position information of the reflector area of ​​the strip reflector in the second direction according to the laser beam fed back by the strip reflector, and sends the measurement position information to the controller. Finally, the controller receives the measurement position information sent by the photoelectric detector and detects the reflector flatness of the strip reflector.

[0130] Based on the detection method of the flatness of the reflector. Accordingly, the present application also provides a specific embodiment of the detection device of the flatness of the reflector.

[0131] like Figure 4 As shown, the device for detecting the flatness of a reflector provided in an embodiment of the present application includes a unit selection module 410 , a position measurement module 420 , a function fitting module 430 , a deviation calculation module 440 and a flatness determination module 450 .

[0132] The unit selection module 410 is used to select a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform, the wafer includes regularly arranged bare die units, and a strip reflector arranged along the first direction is installed on the moving platform.

[0133] The position measurement module 420 is used to control the motion platform to move along the target straight line, use a laser interferometer to emit a laser beam to the strip reflector, and measure the measurement position information of each reflector area of ​​the strip reflector in the second direction one by one. The first direction is perpendicular to the second direction. The target straight line is a straight line where multiple target bare chip units are located, and the reflector area corresponds to the target bare chip unit one by one.

[0134] The function fitting module 430 is used to perform linear fitting on the order of arrangement of each reflector region in the first direction and the measured position information in the second direction to obtain a target fitting function.

[0135] The deviation determination module 440 is used to subtract the measured position information of each reflector area from the corresponding theoretical position information on the target fitting function to obtain the measurement deviation corresponding to each reflector area.

[0136] The flatness determination module 450 is used to determine the flatness of the strip reflector according to the measurement deviation corresponding to each reflector area.

[0137] As an optional embodiment, the unit selection module 410 specifically includes the following units:

[0138] An image acquisition unit, used to acquire a wafer image of a wafer placed on the motion platform;

[0139] The bare die selection unit is used to select a plurality of target bare die units arranged along a first direction from the wafer placed on the moving platform based on the wafer image.

[0140] As an optional embodiment, the die selection unit specifically includes the following subunits:

[0141] A center acquisition subunit, used for acquiring a center bare die unit corresponding to the center of a circle in a wafer placed on a motion platform based on a wafer image;

[0142] The bare die selection subunit is used to extend from the central bare die unit in a first direction to select a plurality of target bare die units in the wafer placed on the moving platform.

[0143] As an optional embodiment, the central acquisition subunit is specifically used for:

[0144] Selecting at least three wafer edge points that are not on the same straight line from the wafer edge of the wafer in the wafer image;

[0145] Determine the center position of the wafer placed on the motion platform according to at least three wafer edge points;

[0146] The die unit corresponding to the center position of the wafer is determined as the central die unit.

[0147] As an optional embodiment, the die selection subunit is specifically used for:

[0148] Extending from the central die unit in a first direction to obtain a target straight line;

[0149] Each bare die unit on a target straight line in a wafer placed on the moving platform is determined as a target bare die unit.

[0150] As an optional embodiment, the position measurement module 420 specifically includes the following units:

[0151] The loop execution unit is used to loop through the following steps until each target die unit on the target straight line is traversed:

[0152] Control the motion platform to move along the direction of the target straight line until the preset detection point of the i-th target bare chip unit on the target straight line is located at the target position of the field of view of the scanning electron microscope, and the initial value of i is 1;

[0153] Using a laser interferometer to emit a laser beam along the strip-shaped reflector to measure measurement position information of a reflector region of the strip-shaped reflector corresponding to the i-th target die unit in the second direction;

[0154] Determine whether i is less than N, where N is the number of target die units;

[0155] When i is less than N, i is updated to i+1.

[0156] As an optional embodiment, the flatness determination module 450 specifically includes the following units:

[0157] A deviation sorting unit, used to sort the measurement deviations corresponding to the reflector regions in order of magnitude to obtain a measurement deviation sequence;

[0158] A deviation acquisition unit, used to acquire the first measurement deviation and the last measurement deviation in the measurement deviation sequence;

[0159] The flatness determination unit is used to obtain the flatness of the strip reflector by combining the first measured deviation with the last measured deviation.

[0160] Based on the detection method of the flatness of the reflector. Accordingly, the present application also provides a specific embodiment of the detection device of the flatness of the reflector.

[0161] like Figure 5 As shown, the device for detecting the flatness of a reflector may include a processor 501 and a memory 502 storing computer program instructions.

[0162] Specifically, the processor 501 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0163] The memory 502 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 502 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In appropriate cases, the memory 502 may include a removable or non-removable (or fixed) medium. In appropriate cases, the memory 502 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 502 is a non-volatile solid-state memory.

[0164] The processor 501 reads and executes the computer program instructions stored in the memory 502 to implement any one of the methods for detecting the flatness of the reflector in the above embodiments.

[0165] In one example, the reflector flatness detection device may further include a communication interface 503 and a bus 510. Figure 5 As shown, the processor 501, the memory 502, and the communication interface 503 are connected via a bus 510 and communicate with each other.

[0166] The communication interface 503 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0167] Bus 510 comprises hardware, software or both, and the parts of the detection equipment of reflector flatness are coupled to each other.For example, but not limitation, bus may comprise accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front side bus (FSB), hypertransmission (HT) interconnection, industrial standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In suitable cases, bus 510 may comprise one or more buses. Although the present application embodiment describes and shows specific bus, the application considers any suitable bus or interconnection.

[0168] In addition, in combination with the reflector flatness detection method in the above embodiment, the embodiment of the present application can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by the processor, any one of the reflector flatness detection methods in the above embodiment is implemented.

[0169] In addition, in combination with the method for detecting the flatness of the reflector in the above-mentioned embodiment, the embodiment of the present application may provide a computer program product for implementation. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the method for detecting the flatness of the reflector provided in any aspect of the above-mentioned embodiment of the present application.

[0170] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0171] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0172] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0173] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0174] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for detecting the flatness of a reflector, It is characterized in that The method comprises: Selecting a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform, the wafer comprising regularly arranged bare die units, and the moving platform being provided with a strip-shaped reflector arranged along the first direction; Control the motion platform to move along the target straight line, use a laser interferometer to emit a laser beam to the strip-shaped reflector, and measure the measurement position information of each reflector area of ​​the strip-shaped reflector in a second direction one by one, wherein the first direction is perpendicular to the second direction, the target straight line is a straight line where the multiple target bare chip units are located, and the reflector areas correspond to the target bare chip units one by one; Performing linear fitting on the order in which the reflector regions are arranged in the first direction and the measured position information in the second direction to obtain a target fitting function; Subtracting the measured position information of each reflector region from the corresponding theoretical position information on the target fitting function to obtain a measurement deviation corresponding to each reflector region; The flatness of the strip-shaped reflector is determined according to the measured deviations corresponding to the reflector regions.

2. The method for detecting the flatness of a reflector according to claim 1, It is characterized in that The method of selecting a plurality of target bare die units arranged along a first direction from a wafer placed on a moving platform comprises: Acquiring a wafer image of the wafer placed on the motion platform; Based on the wafer image, a plurality of the target bare die units arranged along the first direction are selected from the wafer placed on the moving platform.

3. The method according to claim 2, It is characterized in that The step of selecting a plurality of target bare die units arranged along the first direction from the wafer placed on the moving platform based on the wafer image comprises: Based on the wafer image, obtaining a central bare die unit corresponding to the center of a circle in the wafer placed on the motion platform; Extending from the central bare die unit toward the first direction, a plurality of target bare die units in the wafer placed on the moving platform are selected.

4. The method according to claim 3, It is characterized in that The step of acquiring a central bare die unit corresponding to the center of a circle of the wafer placed on the moving platform based on the wafer image includes: Selecting at least three wafer edge points that are not on the same straight line from the wafer edge of the wafer in the wafer image; Determining the center position of the wafer placed on the motion platform according to the at least three wafer edge points; The die unit corresponding to the center position of the wafer is determined as the central die unit.

5. The method according to claim 3, It is characterized in that The step of extending from the central die unit toward the first direction to select a plurality of target die units in the wafer placed on the moving platform includes: Extending from the central die unit toward the first direction to obtain the target straight line; Each of the bare die units on the target straight line in the wafer placed on the moving platform is determined as the target bare die unit.

6. The method according to claim 3, It is characterized in that The method of controlling the motion platform to move along the target straight line, emitting a laser beam to the strip-shaped reflector by using a laser interferometer, and measuring the measurement position information of each reflector area of ​​the strip-shaped reflector in the second direction one by one, comprises: The following steps are executed in a loop until each of the target die units on the target straight line is traversed: Controlling the motion platform to move along the direction of the target straight line until the preset detection point of the i-th target bare chip unit on the target straight line is located at the target position of the field of view of the scanning electron microscope, and the initial value of i is 1; emitting a laser beam to the strip-shaped reflector by using the laser interferometer to measure the measurement position information of the reflector region of the strip-shaped reflector corresponding to the i-th target die unit in the second direction; Determine whether i is less than N, where N is the number of the target die units; When i is less than N, i is updated to i+1.

7. The method according to claim 6, It is characterized in that The preset detection point of the target bare die unit is at least one point on a target detection edge of the target bare die unit, and the target detection edge is an edge of the target bare die unit that is closest to the diameter of the wafer along the first direction.

8. The method according to any one of claims 1 to 7, It is characterized in that Determining the flatness of the strip-shaped reflector according to the measurement deviations corresponding to the reflector regions includes: Sorting the measurement deviations corresponding to the reflector regions in order of magnitude to obtain a measurement deviation sequence; Obtaining a first measurement deviation and a last measurement deviation in the measurement deviation sequence; The first measured deviation and the last measured deviation are added to obtain the flatness of the strip-shaped reflector.

9. A device for detecting the flatness of a reflector, It is characterized in that The device comprises: A unit selection module, used for selecting a plurality of target bare die units arranged along a first direction from a wafer placed on a motion platform, the wafer comprising regularly arranged bare die units, and the motion platform being equipped with a strip-shaped reflector arranged along the first direction; a position measurement module, used for controlling the motion platform to move along a target straight line, using a laser interferometer to emit a laser beam to the strip-shaped reflector, and measuring the measurement position information of each reflector area of ​​the strip-shaped reflector in a second direction one by one, wherein the first direction is perpendicular to the second direction, the target straight line is a straight line where the multiple target bare chip units are located, and the reflector areas correspond to the target bare chip units one by one; A function fitting module, used for performing linear fitting on the order of arrangement of each of the reflector regions in the first direction and the measurement position information in the second direction to obtain a target fitting function; A deviation determination module, used for subtracting the measured position information of each reflector region from the corresponding theoretical position information on the target fitting function to obtain the measurement deviation corresponding to each reflector region; The flatness determination module is used to determine the flatness of the strip-shaped reflector according to the measurement deviation corresponding to each of the reflector regions.

10. A system for detecting the flatness of a reflector. It is characterized in that The system includes a motion platform, a scanning electron microscope, a laser interferometer, a strip reflector, a photoelectric detector and a controller; The motion platform is connected to the controller and is used to move the wafer placed on the motion platform along the direction of the target straight line in response to the movement instruction of the controller; The scanning electron microscope is connected to the controller and is used to identify whether the motion platform deviates from the direction of the target straight line in response to the recognition instruction of the controller when the controller controls the motion platform to move along the direction of the target straight line; The laser interferometer is connected to the controller and is used to emit a laser beam to the strip-shaped reflective mirror in response to a detection instruction of the controller; The strip-shaped reflector is mounted on the motion platform and connected to the photoelectric detector, and is used to receive the laser beam sent by the laser interferometer and feed back the laser beam to the photoelectric detector; The photoelectric detector is connected to the strip-shaped reflector and the controller, and is used to determine the measurement position information of the reflector area of ​​the strip-shaped reflector in the second direction according to the laser beam fed back by the strip-shaped reflector, and send the measurement position information to the controller; The controller is used to execute the method for detecting the flatness of the reflector as described in any one of claims 1-8.

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