Grating test machine and grating test method

Abstract

The invention relates to the field of semiconductor lithography, in particular to a grating testing machine and a grating testing method.The grating testing machine comprises a movable workpiece table, a degree-of-freedom measuring assembly, a machine testing surface and a signal processing end; the movable workpiece table is arranged on the testing surface of the machine table and comprises a testing reading head; a grating to be tested is arranged above the testing surface of the machine table and is opposite to the testing reading head; the movable workpiece table can move on the testing surface of the machine table to drive the reading head to scan the grating to be tested; the reading head obtains scanning degree-of-freedom change data by scanning the grating to be measured; the degree-of-freedom measurement assembly is used for measuring the movable workpiece table to obtain reference degree-of-freedom change data of the movable workpiece table; and the signal processing end is used for obtaining defect surface type information of the grating to be detected according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data. According to the invention, the working stability and positioning accuracy of the to-be-detected grating are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor lithography, and in particular to a grating testing machine and a grating testing method. Background Art

[0002] Currently, the positioning of a lithography machine (i.e., a photolithography machine) is usually performed with the aid of a positioning grating, which includes many closely arranged fine gratings. The lithography machine reads the grating information on the positioning grating through a reader, and can determine the relative changes between the reader and the positioning grating in each degree of freedom.

[0003] However, as the structural size on the grating is getting smaller and smaller, the manufacturing of the positioning grating is becoming more and more difficult, which leads to a lower and lower yield rate in actual production. The gratings that pass the good product inspection will also have more or less defects. These defects will cause inaccurate measurements and wafer worktable movement jumps in the subsequent process of using the positioning grating for degree of freedom measurement, and ultimately lead to exposure errors. The current solution is to perform fault-tolerant processing through the two-dimensional grating reader and algorithm on the wafer worktable.

[0004] However, with the development of process technology, the requirements for accuracy of positioning and degree of freedom measurement are becoming increasingly higher. Therefore, how to eliminate the wafer worktable movement jump caused by defects in the positioning grating during the production process and reduce exposure errors has become an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a grating testing machine and a grating testing method to solve the problems of wafer worktable position jump and large exposure error in the prior art.

[0006] In order to solve the above technical problems, the present invention provides a grating test machine, including a movable workpiece table, a degree of freedom measurement component, a machine test surface and a signal processing end;

[0007] The movable workpiece stage is arranged on the test surface of the machine stage and includes a test reader;

[0008] The grating to be tested is arranged above the test surface of the machine platform and opposite to the test reading head;

[0009] The movable workpiece table can move on the test surface of the machine table, driving the reading head to scan the grating to be tested;

[0010] The reading head obtains scanning degree of freedom change data by scanning the grating to be measured;

[0011] The degree of freedom measurement component is used to measure the mobile workpiece stage to obtain reference degree of freedom change data of the mobile workpiece stage;

[0012] The signal processing end is used to obtain the defective surface profile information of the grating to be measured according to the reference degree of freedom change data and the scanning degree of freedom change data.

[0013] Optionally, in the grating testing machine, the moving workpiece table is a floating workpiece table.

[0014] Optionally, in the grating testing machine, the floating workpiece table is a magnetic levitation workpiece table;

[0015] The machine table testing surface includes a permanent magnet disposed below the magnetic levitation workpiece table.

[0016] Optionally, in the grating testing machine, the magnetic levitation workpiece table includes a working motor and a moving component;

[0017] The magnetic levitation workbench drives the moving component to move on the machine table testing surface through the working motor.

[0018] Optionally, in the grating testing machine, the magnetic levitation workpiece table is disposed in a vacuum chamber.

[0019] Optionally, in the grating testing machine, the testing read head is a two-dimensional read head.

[0020] Optionally, in the grating testing machine, the degree of freedom measurement component includes an x-direction interferometer, a y-direction interferometer, and a z-direction interferometer;

[0021] The moving workpiece table includes an x-direction mirror, a y-direction mirror, and a z-direction first mirror; a z-direction second mirror is further disposed above the moving workpiece table;

[0022] The x-direction mirror is perpendicularly disposed to the light output direction of the x-direction interferometer, and the y-direction mirror is perpendicularly disposed to the light output direction of the y-direction interferometer;

[0023] The emitted light of the z-direction interferometer is reflected by the z-direction first mirror, then vertically enters the z-direction second mirror upward in a direction perpendicular to the movement direction of the moving workpiece table, and is reflected by the z-direction second mirror, passes through the z-direction first mirror, and returns to the z-direction interferometer.

[0024] Optionally, in the grating testing machine, the degree of freedom measurement component includes one x-direction interferometer, one y-direction interferometer, and two z-direction interferometers;

[0025] The two z-direction interferometers respectively correspond to two opposite sides of the moving workpiece table.

[0026] A grating testing method, which is a grating testing method implemented by any one of the above-mentioned grating testing machines, includes:

[0027] Sending a moving scan instruction to the moving workbench;

[0028] During the moving scan of the moving workbench, receiving the reference degree-of-freedom change data corresponding to each sampling point from the degree-of-freedom testing component, and receiving the scan degree-of-freedom change data corresponding to the sampling point from the test read head;

[0029] Obtaining the defective surface profile information of the grating to be tested according to the reference degree-of-freedom change data and the scan degree-of-freedom change data.

[0030] Optionally, in the grating testing method, the sending a moving scan instruction to the moving workbench includes:

[0031] Sending a step scan instruction to the moving workbench; wherein, a sampling point is determined after each step; the range of the step distance corresponding to the step scan instruction is from 0.01 mm to 0.10 mm, including the endpoint values.

[0032] The grating testing machine provided by the present invention includes a moving workpiece stage, a degree-of-freedom measurement component, a machine table testing surface, and a signal processing end; the moving workpiece stage is arranged on the machine table testing surface and includes a testing read head; the grating to be tested is arranged above the machine table testing surface and is opposite to the testing read head; the moving workpiece stage can move on the machine table testing surface, driving the read head to scan the grating to be tested; the read head obtains scanning degree-of-freedom change data through scanning the grating to be tested; the degree-of-freedom measurement component is used to measure the moving workpiece stage to obtain the reference degree-of-freedom change data of the moving workpiece stage; the signal processing end is used to obtain the defective surface profile information of the grating to be tested according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data. In the present invention, the grating to be tested is pre-placed on the grating testing machine. While scanning the grating to be tested with the testing read head to read the degree-of-freedom change data during scanning, another set of degree-of-freedom measurement components is also used to read the degree-of-freedom change data of the moving workpiece stage where the read head is located during scanning. Since the read head is fixed on the moving workpiece stage, ideally, the degree-of-freedom change data from the above two sources should be consistent. However, in fact, due to the defects of the grating to be tested, the two sets of degree-of-freedom change data may not be consistent. Therefore, by comparing the reference degree-of-freedom change data with the scanning degree-of-freedom change data, the defective surface profile information of the grating to be tested can be obtained, that is, the defect distribution and specific defect parameters on the grating to be tested can be known, thereby avoiding unknown wafer workpiece stage position jumps and exposure errors during the subsequent working process of the grating to be tested, and improving the working stability and positioning accuracy of the grating to be tested. The present invention also provides a grating testing method having the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0034] Figure 1 FIG. is a schematic structural diagram of a specific embodiment of the grating testing machine provided by the present invention;

[0035] Figure 2 FIG. is a partial structural diagram of another specific embodiment of the grating testing machine provided by the present invention;

[0036] Figure 3 FIG. is a partial structural diagram of yet another specific embodiment of the grating testing machine provided by the present invention;

[0037] Figure 4A partial structural schematic diagram of still another specific embodiment of the grating testing machine provided by the present invention;

[0038] Figure 5 A partial structural schematic diagram of yet another specific embodiment of the grating testing machine provided by the present invention;

[0039] Figure 6 A partial structural schematic diagram of a specific embodiment of the grating testing machine provided by the present invention;

[0040] Figure 7 A flowchart of a specific embodiment of the grating testing method provided by the present invention;

[0041] Figure 8 A schematic diagram of a grating to be tested in a specific embodiment of the grating testing method provided by the present invention.

[0042] In the figure, it includes: 10 - machine table testing surface, 20 - moving workpiece table, 30 - degree - of - freedom measurement component, 40 - signal processing end, 01 - grating to be tested, 02 - special mark, 21 - testing read head, 22 - permanent magnet, 23 - x - direction mirror, 24 - y - direction mirror, 25 - z - direction first mirror, 26 - z - direction second mirror, 31 - x - direction interferometer, 32 - y - direction interferometer, 33 - z - direction interferometer. Specific embodiment

[0043] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] The core of the present invention is to provide a grating testing machine. A structural schematic diagram of one of its specific embodiments is as Figure 1 shown, which is called Specific Embodiment 1, and includes a moving workpiece table 20, a degree - of - freedom measurement component 30, a machine table testing surface 10, and a signal processing end 40;

[0045] The moving workpiece table 20 is arranged on the machine table testing surface 10 and includes a testing read head 21;

[0046] The grating to be tested 01 is arranged above the machine table testing surface 10 and is opposite to the testing read head 21;

[0047] The moving workpiece table 20 can move on the machine table testing surface 10, driving the read head to scan the grating to be tested 01;

[0048] The reading head obtains the scanning degree-of-freedom change data by scanning the grating 01 to be measured;

[0049] The degree-of-freedom measurement component 30 is used to measure the moving workpiece table 20 to obtain the reference degree-of-freedom change data of the moving workpiece table 20;

[0050] The signal processing end 40 is used to obtain the defective surface profile information of the grating 01 to be measured according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data.

[0051] The defective surface profile information is the defective distribution information on the surface of the grating 01 to be measured tested by this grating testing machine.

[0052] As a preferred embodiment, the moving workpiece table 20 is a floating workpiece table.

[0053] The floating workpiece table can be an air-floating workpiece table or a magnetic levitation worktable. The floating workpiece table does not need to consider the contact friction force with the testing surface 10 of the machine. The position adjustment of the floating workpiece table is more controllable, and the scanning position and distance control of the reading head are more accurate, which can improve the accuracy of the finally obtained defective surface profile information.

[0054] Furthermore, the floating workpiece table is a magnetic levitation workpiece table;

[0055] The testing surface 10 of the machine includes a permanent magnet 22 arranged below the magnetic levitation workpiece table.

[0056] In this preferred embodiment, it is defined that the floating workpiece table is a magnetic levitation workpiece table. The magnetic levitation worktable works more stably and moves more controllably, which can further improve the accuracy of the finally obtained defective surface profile information.

[0057] Furthermore, the magnetic levitation workpiece table includes a working motor and a moving component;

[0058] The magnetic levitation worktable drives the moving component to move on the testing surface 10 of the machine through the working motor.

[0059] In other words, in this preferred embodiment, the mechanism for driving the magnetic levitation worktable to move on the testing surface 10 of the machine is arranged on the magnetic levitation worktable. The magnetic levitation worktable does not need to realize its own movement through an external structure, which can further improve the positioning accuracy of the magnetic levitation worktable, drive the movement accuracy of the testing reading head 21, reduce the system complexity at the same time, improve the system integration degree, and is beneficial to the normal and stable operation of the equipment.

[0060] Furthermore, the magnetic levitation workpiece table is arranged in a vacuum chamber.

[0061] Since the defects on the grating 01 to be measured are very small and are extremely vulnerable to environmental factors during the testing process, in this preferred embodiment, the magnetic levitation workpiece stage is placed in a vacuum chamber, thus avoiding the problem of inaccurate measurement caused by air disturbance and local air pressure change in the test head 21 and the degree of freedom measurement component 30, and further improving the accuracy of the finally obtained defect surface profile information.

[0062] Among them, the test head 21 is a two-dimensional head.

[0063] Please refer to Figure 2 and Figure 3 , Figure 2 which is a schematic diagram of the optical signal interaction between the test head 21 and the grating 01 to be measured when moving in the X or Y direction provided by the embodiment of the present application; Figure 3 which is a schematic diagram of the optical signal interaction between the test head 21 and the grating 01 to be measured when moving in the Z direction provided by the embodiment of the present application. Each test head includes two measurement light sources and one reference light source. The two measurement light sources correspond to two measurement lights (including the first measurement light A and the second measurement light B), and one reference light source corresponds to one reference light C. In the area corresponding to the grating 01 to be measured, the test head 21 emits the reference light and the measurement light to the corresponding grating 01 to be measured. After the diffraction of the reference light and the measurement light by the grating 01 to be measured, positive and negative first-order lights are generated, and the grating 01 to be measured reflects the positive and negative first-order lights back to the test head 21. The position information of the magnetic levitation wafer workbench can be analyzed according to the generated positive and negative first-order lights. As Figure 2 and Figure 3 shown, if moving in the horizontal direction (X, Y direction), the positive and negative first-order light information is the same, and if moving in the vertical direction (Z direction), the positive and negative first-order light information is opposite. For details, please refer to the related technology, and the present invention will not be elaborated in detail here.

[0064] As a preferred embodiment, the degree of freedom measurement component 30 includes an x-direction interferometer 31, a y-direction interferometer 32, and a z-direction interferometer 33;

[0065] The moving workpiece stage 20 includes an x-direction mirror 23, a y-direction mirror 24, and a z-direction first mirror 25; a z-direction second mirror 26 is further provided above the moving workpiece stage 20;

[0066] The x-direction mirror 23 is perpendicularly arranged to the light output direction of the x-direction interferometer 31, and the y-direction mirror 24 is perpendicularly arranged to the light output direction of the y-direction interferometer 32;

[0067] After the outgoing light emitted by the z-direction interferometer 33 is reflected by the first z-direction mirror 25, it enters the second z-direction mirror 26 vertically upward in the direction perpendicular to the movement direction of the moving workpiece table 20, and is reflected by the second z-direction mirror 26, passes through the first z-direction mirror 25, and returns to the z-direction interferometer 33.

[0068] Please refer to Figure 4 , in this preferred embodiment, an interferometer is used in cooperation with a corresponding mirror in each direction to measure the change in the degree of freedom of the moving worktable. It can also be referred to Figure 6 , the x-direction mirror 23 faces the outgoing light direction of the x-direction interferometer 31. After the outgoing light of the x-direction interferometer 31 is emitted, when it encounters the x-direction mirror 23, it is directly reflected back to the x-direction interferometer 31 for distance measurement. Similarly, for the y-direction interferometer 32 and the corresponding y-direction mirror 24, while the z-direction interferometer 33 and the corresponding first z-direction mirror 25 and second z-direction mirror 26 are slightly more complex. Since the measurement target of the z-direction interferometer 33 is to measure the position change of the moving workpiece table 20 in the z direction, therefore, it is necessary to make the light of the z-direction interferometer 33 include a travel in the z direction. In this specific embodiment, first, the first z-direction mirror 25 is used to reflect the outgoing light of the z-direction interferometer 33 whose outgoing light direction is in the plane of the moving workpiece table 20 once, so that the reflected outgoing light travels upward in the direction perpendicular to the movement direction of the moving workpiece table 20, that is, in the z direction. And the second z-direction mirror 26 is set above the moving workpiece table 20 in advance to return the light along the original path and re-enter the z-direction interferometer 33. Thus, the acquisition of the data on the change in the degree of freedom in the z direction is completed. It can be referred to Figure 5 , Figure 5 is a three-dimensional schematic diagram of the moving workpiece table 20 in this specific embodiment. In this preferred embodiment, an interferometer and a corresponding mirror are adopted, which greatly improves the accuracy of the degree-of-freedom detection of the degree-of-freedom detection component, and further improves the accuracy of the finally obtained defective surface shape information.

[0069] Furthermore, the degree-of-freedom measurement component 30 includes one x-direction interferometer 31, one y-direction interferometer 32 and two z-direction interferometers 33;

[0070] The two z-direction interferometers 33 respectively correspond to two opposite sides of the moving workpiece table 20.

[0071] In this preferred embodiment, there are two z-direction interferometers 33 disposed opposite to the moving workpiece table 20. The two z-direction interferometers 33 can respectively detect the changes in the z direction of two opposite surfaces of the moving workpiece table 20, so as to further determine the warping degree of the moving workpiece table 20 in the direction of the connection line of the two opposite surfaces, that is, the degrees of freedom that can be measured by the degree-of-freedom measurement assembly 30 are increased, and the versatility of the grating testing machine platform is improved.

[0072] Specifically, the above three interferometers are all multi-point interferometers. Each multi-point interferometer corresponds to multiple measurement points. For example, the x-direction interferometer 31 may include three measurement points, and the three measurement points form an "L" shape. According to the difference in the distance changes between the measurement points, the rotational change of the corresponding surface of the moving workpiece table 20 along the connection line between any two of the three measurement points can be measured, and the changes in the six degrees of freedom of the moving workpiece table 20 can be calculated.

[0073] Furthermore, two sets of z-direction interferometers 33 can be respectively disposed on two sets of opposite side surfaces of the moving workpiece table 20, so that the warping degrees of the moving workpiece table 20 in the x direction and the y direction can be obtained, further improving the versatility of the present invention and the guiding significance of the obtained data for subsequent other processes.

[0074] The grating testing machine provided by the present invention includes a moving workpiece stage 20, a degree-of-freedom measurement component 30, a machine testing surface 10, and a signal processing end 40; the moving workpiece stage 20 is arranged on the machine testing surface 10 and includes a testing head 21; a grating to be tested 01 is arranged above the machine testing surface 10 and is opposite to the testing head 21; the moving workpiece stage 20 can move on the machine testing surface 10, driving the testing head to scan the grating to be tested 01; the testing head obtains scanning degree-of-freedom change data through scanning the grating to be tested 01; the degree-of-freedom measurement component 30 is used to measure the moving workpiece stage 20 to obtain the reference degree-of-freedom change data of the moving workpiece stage 20; the signal processing end 40 is used to obtain the defective surface profile information of the grating to be tested 01 according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data. In the present invention, the grating to be tested 01 is pre-placed on the grating testing machine. While scanning the grating to be tested 01 with the testing head 21 to read the degree-of-freedom change data during scanning, another set of degree-of-freedom measurement component 30 is also used to read the degree-of-freedom change data of the moving workpiece stage 20 where the testing head is located during scanning. Since the testing head is fixed on the moving workpiece stage 20, ideally, the degree-of-freedom change data from the above two sources should be consistent. However, in fact, due to the defects of the grating to be tested 01, the two sets of degree-of-freedom change data may not be consistent. Therefore, by comparing the scanning degree-of-freedom change data with the reference degree-of-freedom change data, the defective surface profile information of the grating to be tested 01 can be obtained, that is, the defect distribution and specific defect parameters on the grating to be tested 01 can be known, thereby avoiding unknown wafer workpiece stage position jumps and exposure errors during the subsequent working process of the grating to be tested 01, and improving the working stability and positioning accuracy of the grating to be tested 01.

[0075] The present invention also provides a grating testing method. The schematic flow diagram of a specific embodiment is as Figure 7 shown, which is called the second specific embodiment. The grating testing method is a grating testing method implemented by the grating testing machine as described in any one of the above. It includes:

[0076] S101: Send a moving scan instruction to the moving workbench.

[0077] After sending the moving scan instruction, the moving workbench starts to work, and the data acquisition in the subsequent steps is all obtained during the working process of the moving workbench.

[0078] As a preferred embodiment, this step includes:

[0079] Send a stepping scan instruction to the moving workbench; wherein, a sampling point is determined after each step; the range of the step distance corresponding to the stepping scan instruction is from 0.01 mm to 0.10 mm, including the endpoint values.

[0080] In this preferred embodiment, using the stepping scan instruction, the moving workbench makes a stepping movement. Each time it moves one step, the stopped position is a sampling point. The stepping scan has strong operability, and the collected data is more regular, which can reduce the amount of calculation required to obtain the defective surface shape information subsequently.

[0081] In this preferred embodiment, the range of the step distance of the stepping scan instruction is further given as from 0.01 mm to 0.10 mm, including the endpoint values, such as any one of 0.010 mm, 0.032 mm, or 0.100 mm. It can be seen that if the step distance is too small, the time spent will increase greatly, and the cost will also increase accordingly. However, if the step distance is too large, the representativeness of the final sampled data will decrease, resulting in a decrease in the accuracy of the final defective surface shape information. The above range is the best range after a large number of theoretical calculations and actual tests. Of course, it can also be changed accordingly according to the actual situation, and the present invention does not limit this here. For example, further, the range of the step distance can be limited to from 0.01 mm to 0.05 mm.

[0082] S102: During the movement and scan of the moving workbench, receive the reference degree-of-freedom change data corresponding to each sampling point from the degree-of-freedom test component, and receive the scan degree-of-freedom change data corresponding to the sampling point from the test head 21.

[0083] S103: Obtain the defective surface shape information of the grating 01 to be measured according to the reference degree-of-freedom change data and the scan degree-of-freedom change data.

[0084] The grating testing method in this specific embodiment corresponds to the grating testing machine platform in the previous text. Therefore, the steps and specific details in this specific embodiment can refer to the specific description of the grating testing machine platform in the previous text, and will not be elaborated here one by one.

[0085] As a preferred embodiment, after obtaining the defective surface shape information, it further includes:

[0086] A1: Receive a grating surface shape calibration instruction.

[0087] A2: Correct the grating surface shape calibration instruction according to the defective surface shape information to obtain a target surface shape calibration instruction.

[0088] The grating surface profile measurement and calibration instruction refers to other surface profile measurement and calibration instructions for the surface profile of the grating 01 to be measured. That is, after obtaining the defective surface profile information of the present invention, other measurement and calibration can be corrected according to the defective surface profile information, improving the accuracy of other measurement and calibration of the grating 01 to be measured and enhancing the creativity of the present invention. The surface profile of the grating is the characteristic information on the surface of the grating. For example, the defective surface profile information refers to the defective distribution information on the surface of the grating, and there are also other types of surface profile information. The surface profile measurement and calibration instruction is used to obtain the corresponding surface profile information.

[0089] The grating testing method provided by the present invention includes sending a moving scan instruction to the moving workbench; during the moving scan of the moving workbench, receiving the corresponding reference degree-of-freedom change data for each sampling point from the degree-of-freedom testing component, and receiving the corresponding scan degree-of-freedom change data for the sampling point from the test head 21; and obtaining the defective surface profile information of the grating 01 to be measured according to the reference degree-of-freedom change data and the scan degree-of-freedom change data. The present invention pre-places the grating 01 to be measured on the grating testing machine table. While using the test head 21 to scan the grating 01 to be measured to read the degree-of-freedom change data during scanning, another set of degree-of-freedom measurement components 30 is also used to read the degree-of-freedom change data of the moving workpiece table 20 where the head is located during scanning. Since the head is fixed on the moving workpiece table 20, in an ideal state, the degree-of-freedom change data from the above two sources should be consistent. However, in reality, due to the defects of the grating 01 to be measured, the two sets of degree-of-freedom change data may not be consistent. Therefore, by comparing the reference degree-of-freedom change data with the scan degree-of-freedom change data, the defective surface profile information of the grating 01 to be measured can be obtained, that is, the defect distribution and specific defect parameters on the grating 01 to be measured can be known, thereby avoiding unknown wafer workpiece table position jumps during the subsequent working process of the grating 01 to be measured, which may cause exposure errors, and improving the working stability and positioning accuracy of the grating 01 to be measured.

[0090] The following gives a step of testing the grating 01 to be measured in actual operation, including:

[0091] Step 1: Determine the zero position after measuring the special mark 02 on the grating 01 to be measured (as Figure 8 shown, Figure 8 a grating to be measured including a special mark 02 for positioning the zero position is given).

[0092] Step 2: Select a certain step size, such as 0.05 mm or 0.01 mm, for row-by-row scanning.

[0093] Step 3: The two-dimensional grating head can read out the grating surface profile and the relative position, and this relative position corresponds one-to-one with the position measured by the interferometer method.

[0094] Step 4: However, when there are defects on the grating, the two-dimensional grating reader will jump (vertically or horizontally) at the defective points. Since the interferometer system is not affected, the interferometer will record this position information, and thus the defects on the grating will be recorded.

[0095] Step 5: After the reader completes the full-area scan on each grating, the surface profile information and defect information of the grating are recorded. Thus, the full-area information of the grating is obtained.

[0096] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0097] It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0098] The grating testing machine platform and the grating testing method provided by the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A grating testing machine, characterized in that, It includes a moving workpiece stage, a degree-of-freedom measurement component, a machine table test surface, and a signal processing end; The moving workpiece stage is arranged on the machine table test surface and includes a test head; The grating to be measured is arranged above the machine table test surface and is opposite to the test head; The moving workpiece stage can move on the machine table test surface, driving the test head to scan the grating to be measured; The test head obtains scanning degree-of-freedom change data by scanning the grating to be measured; The degree-of-freedom measurement component is used to measure the moving workpiece stage to obtain the reference degree-of-freedom change data of the moving workpiece stage; The signal processing end is used to obtain the defective surface profile information of the grating to be measured according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data.

2. The grating testing machine according to claim 1, wherein The moving workpiece stage is a floating workpiece stage.

3. The grating testing machine according to claim 2, characterized in that, The floating workpiece stage is a magnetic levitation workpiece stage; The machine table test surface includes a permanent magnet arranged below the magnetic levitation workpiece stage.

4. The grating testing machine according to claim 3, wherein The magnetic levitation workpiece stage includes a working motor and a moving component; The magnetic levitation workbench drives the moving component to move on the machine table test surface through the working motor.

5. The grating testing machine according to claim 3, wherein The magnetic levitation workpiece stage is arranged in a vacuum chamber.

6. The grating testing machine according to claim 1, wherein, The test head is a two-dimensional test head.

7. The grating testing machine according to any one of claims 1 to 6, characterized in that, The degree-of-freedom measurement component includes an x-direction interferometer, a y-direction interferometer, and a z-direction interferometer; The moving workpiece stage includes an x-direction mirror, a y-direction mirror, and a z-direction first mirror; a z-direction second mirror is also arranged above the moving workpiece stage; The x-direction mirror is arranged perpendicular to the light output direction of the x-direction interferometer, and the y-direction mirror is arranged perpendicular to the light output direction of the y-direction interferometer; The light emitted by the z-direction interferometer is reflected by the z-direction first mirror, then vertically enters the z-direction second mirror upward perpendicular to the moving direction of the moving workpiece stage, and is reflected by the z-direction second mirror, passes through the z-direction first mirror, and returns to the z-direction interferometer.

8. The grating testing machine according to claim 7, wherein, The degree-of-freedom measurement component includes one x-direction interferometer, one y-direction interferometer, and two z-direction interferometers; The two z-direction interferometers respectively correspond to two opposite sides of the moving workpiece stage.

9. A grating testing method, characterized in that, The grating test method is a grating test method implemented by the grating test machine table according to any one of claims 1 to 8, and includes: Sending a moving scan instruction to the moving workbench; During the moving scan of the moving workbench, receiving the reference degree-of-freedom change data corresponding to each sampling point from the degree-of-freedom test component, and receiving the scanning degree-of-freedom change data corresponding to the sampling point from the test head; Obtaining the defective surface profile information of the grating to be measured according to the reference degree-of-freedom change data and the scanning degree-of-freedom change data.

10. The grating testing method according to claim 9, characterized in that, The sending the moving scan instruction to the moving workbench includes: Sending a step scan instruction to the moving workbench; wherein, a sampling point is determined after each step; the range of the step size corresponding to the step scan instruction is from 0.01 mm to 0.10 mm, including the endpoint values.

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