Step height standard sample block

Abstract

The utility model provides a step height standard sample block which is used for calibrating measurement of a step measuring instrument. The step height standard sample block comprises a substrate and a calibration plate which is arranged on the substrate and is used for calibrating the position of a probe, wherein the calibration plate is provided with a positioning area, a coarse calibration area and a fine calibration area; wherein the positioning mark has directivity and is used for indicating the center of a view field of the step measuring instrument, each of the coarse calibration area and the fine calibration area comprises at least one position calibration structure equivalent to a bulge and / or a recess of the calibration plate, and the position calibration structure of the fine calibration area is smaller than the position calibration structure of the coarse calibration area; when the probe of the step measuring instrument scans the position calibration structures in different areas, step signals related to the position calibration structures are output, and at least one time of fine calibration of the step measuring instrument can be completed according to the step signals. According to the invention, the calibration of the step measuring instrument is completed through the two position calibration structures with different sizes, and the calibration precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of step meter measurement, in particular to a step height standard sample block used for calibrating the measurement accuracy of a step meter. Background Art

[0002] With the development of the semiconductor industry, integrated circuits, large-scale integrated circuits, and micro-electromechanical systems (MEMS) devices contain a large number of step structures. These structures have a direct impact on the overall performance of the device. Therefore, accurate measurement and monitoring of step structures is an important means to ensure device quality. Currently, step height measurement instruments mainly include step meters, nanometer measuring machines, and white light interferometers.

[0003] In the semiconductor industry, step height measurement using a step gauge is a common method. The main methods for measuring steps are contact measurement and optical measurement. A common step gauge consists of a movable, rotating scanning platform, a sensor / detector for measuring interaction with the sample, and a control system for controlling the scanning platform and processing data. During measurement, the stylus of the step gauge gently slides across the surface being measured, acquiring a motion signal reflecting the sample's surface profile. The sensor / detector converts the stylus' motion signal into an electrical signal and transmits it to the control system. After a series of data processing steps, including noise reduction, filtering, and rectification, a measurement result reflecting the sample's surface topography is obtained.

[0004] In order to ensure the accuracy and reliability of the measurement results of the step measuring instrument, strict calibration work must be carried out before using it for measurement, such as calibrating the step measuring instrument with the help of a step height standard block. For example, in order not to block the navigation camera of the step measuring instrument, the stylus is not within the field of view of the navigation camera, so it is necessary to calibrate the center of the field of view of the step measuring instrument and the relative position of the stylus. However, the existing step height standard block has a single function and cannot meet the calibration needs of multiple scenarios. For example: the step height standard block only includes a raised or recessed step structure, which can realize the step height calibration of the step measuring instrument base, but cannot realize the calibration of the center of the field of view of the step measuring instrument and the relative position of the stylus, which can easily lead to deviations in the test results; for example, if the stylus is contaminated, worn or even has surface defects, if the step measuring instrument calibrated with the stylus is used for measurement without knowing it, the measurement result will be inconsistent with the actual properties of the sample, misleading the measurement personnel. Utility Model Content

[0005] The step height standard block provided by the utility model can, on the basis of conventional calibration of the step measuring instrument, also calibrate the relative position of the field of view center and the measuring needle of the step measuring instrument, and can solve the technical problem that the step height standard block in the prior art has a single function and cannot meet the calibration requirements of multiple scenarios.

[0006] In a first aspect, an embodiment of the present application provides a step height standard block for calibrating a step measuring instrument; the step height standard block includes a substrate and a calibration plate disposed on the substrate for calibrating the position of a stylus; the calibration plate is provided with a positioning area, a coarse calibration area, and a fine calibration area;

[0007] The positioning area includes at least one positioning mark for indicating the starting point of the stylus scanning; the coarse calibration area includes at least one first position calibration structure that is raised and / or recessed relative to the calibration plate; the fine calibration area is located between the positioning area and the coarse calibration area; the fine calibration area includes at least one second position calibration structure that is raised and / or recessed relative to the calibration plate, and the size of the second position calibration structure is smaller than that of the first position calibration structure.

[0008] In some embodiments, the positioning mark is a pattern with a directional intersection, and the pattern with a directional intersection is any one of a T-line, a cross line, or a triangle line, and the center of the field of view of the step measuring instrument is located at the intersection of the T-line, the cross line, or the triangle line;

[0009] The positioning mark, the first position calibration structure and the second position calibration structure are symmetrically distributed about the same position center.

[0010] In some embodiments, the step of the first position calibration structure in the coarse calibration area includes at least three step edges, namely a first step edge, a second step edge, and a third step edge; the first step edge is parallel to a first direction; the second step edge and the third step edge are not parallel to each other and are not parallel to the first direction; wherein the first direction is a preset scanning direction of the stylus;

[0011] The second position calibration structure in the fine calibration area is the same as the first position calibration structure in the coarse calibration area;

[0012] The coarse calibration area also includes an auxiliary position calibration structure; the auxiliary position calibration structure includes a raised and / or recessed step relative to the calibration plate, and at least one step edge of the step is parallel to the second step edge or the third step edge.

[0013] In some embodiments, the first position calibration structure includes two isosceles right triangles that are raised and / or recessed relative to the calibration plate, the hypotenuses of the two isosceles right triangles are parallel and arranged opposite to each other, and each of the two isosceles right triangles has a right-angled side parallel to the first direction;

[0014] Alternatively, the first position calibration structure includes two isosceles right triangles that are raised and / or recessed relative to the calibration plate, the hypotenuses of the two isosceles right triangles are arranged perpendicularly relative to each other, and each of the two isosceles right triangles has a right-angled side parallel to the first direction.

[0015] In some embodiments, a step height calibration area is further provided on the calibration plate; the step height calibration area includes a third position calibration structure that is raised and / or recessed relative to the calibration plate.

[0016] In some embodiments, a stylus defect recognition area is further provided on the calibration plate; the stylus defect recognition area includes a fourth position calibration structure that is raised or recessed and forms different angles with the first direction at different locations.

[0017] In some embodiments, the upper plane of the fourth position marking structure is a pattern with curves, and the pattern with curves is a plurality of circular rings and / or semicircular rings.

[0018] In some embodiments, the heights of the protrusions or depressions of the first position marking structure, the second position marking structure, the third position marking structure, and the fourth position marking structure are not completely the same.

[0019] In some embodiments, the step height standard block further includes a linear calibration area provided on the substrate; the linear calibration area includes a plane having an angle with the substrate, and is used for performing linear calibration on the step measuring instrument.

[0020] In some embodiments, the step height standard block further includes a detachable protective cover disposed on the base plate; the calibration plate is located in the protective cover.

[0021] The step height standard block for calibrating the measurement accuracy of a step measuring instrument provided in an embodiment of the present application includes a substrate and a calibration plate arranged on the substrate for calibrating the position of a stylus, wherein a positioning area, a coarse calibration area and a fine calibration area are provided on the calibration plate; wherein the positioning mark is a directional positioning mark for indicating the relative position of the field of view center of the step measuring instrument and the stylus, and the coarse calibration area and the fine calibration area each include at least one position calibration structure equivalent to the protrusion and / or depression of the calibration plate, wherein the position calibration structure of the fine calibration area is smaller than the position calibration structure of the coarse calibration area; when the stylus of the step measuring instrument scans to the position calibration structure of different areas, a step signal related to the position calibration structure will be output, and at least one fine calibration of the step measuring instrument can be completed according to the step signal.

[0022] This application first calibrates the step measuring instrument through the positioning marks in the positioning area and the position calibration structure in the coarse calibration area to determine the relative position between the center of the field of view and the scanning starting point of the probe, thereby reducing the error caused by the deviation of the scanning starting point. The step measuring instrument is then precisely calibrated through the position calibration structure in the fine calibration area, thereby improving the calibration accuracy and ensuring the accuracy and reliability of the measurement results of the step measuring instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] Figure 1 A top view of the structure of a step height standard sample block provided in one embodiment of the present application (the substrate is not shown);

[0025] Figure 2 A top view of the structure of the coarse calibration area provided in one embodiment of the present application;

[0026] Figure 3 A top view of a first position calibration structure provided in one embodiment of the present application;

[0027] Figure 4 A top view of the structure of a step height standard sample block provided in another embodiment of the present application;

[0028] Figure 5 A top view of a fourth position calibration structure provided in one embodiment of the present application;

[0029] Figure 6 A structural diagram of a step height standard sample block provided in another embodiment of the present application;

[0030] Figure 7 A structural diagram of a step height standard sample block provided in another embodiment of the present application.

[0031] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted under different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0033] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0034] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated before and after are in an "or" relationship. The "connection" and "connection" mentioned in this application, unless otherwise specified, include direct and indirect connections (connections).

[0035] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0036] Figure 1 This is a top view of the structure of a step height standard sample block provided in one embodiment of the present application (the substrate is not shown). Figure 1As shown, the step height standard block provided in this embodiment for calibrating a step measuring instrument includes a substrate 10 and a calibration plate 20 for calibrating the position of a stylus arranged on the substrate 10, wherein the calibration plate 20 is provided with a positioning area 201, a coarse calibration area 202 and a fine calibration area 203.

[0037] In some step measuring instruments equipped with a navigation camera, the scan length and starting point are determined based on the image captured by the navigation camera when measuring a sample. For ease of control, the step measuring instrument's control system defaults to the center of the navigation camera's field of view as the scanning starting point. The control system then moves the stylus along the defined scanning direction and the defined scanning length to complete the scan. However, in practice, to avoid obstructing the navigation camera, the center of the navigation camera's field of view and the stylus are not aligned on the same vertical line. Therefore, the relative position of the field of view center and the stylus must be calibrated before the scan begins. This allows the stylus's scanning starting point to be moved to the center of the field of view after the scan begins.

[0038] In this embodiment, the positioning area 201 includes at least one positioning mark for indicating the starting point of the stylus scanning. When calibrating the step measuring instrument, the positioning mark is used to determine the relative position of the center of the field of view of the step measuring instrument and the stylus of the step measuring instrument, that is, the positioning mark can be made to coincide with the center of the field of view of the step measuring instrument, that is, the scanning starting point of the stylus can be set based on the positioning mark.

[0039] Before calibrating the step measuring instrument, the relative position of the field of view center of the step measuring instrument and the stylus can be adjusted through the positioning mark, that is, the relative position between the field of view center and the scanning starting point of the stylus is determined. This can ensure that before the step measuring instrument scans the sample, the stylus is moved according to the positioning mark and the relative position obtained by calibration so that it coincides with the field of view center of the step measuring instrument or is on the same straight line, which can reduce the error caused by deviation of the scanning starting point.

[0040] In some embodiments, the positioning mark can be a pattern with a directional intersection, such as a T-line, a crosshair, or a triangle. These lines have two intersecting lines, and the intersection clearly points to a specific direction or position, allowing for rapid identification and understanding of their direction and positioning. Therefore, using a pattern with directional intersections, the target position can be accurately located without significant positioning errors due to minor changes in environmental factors. When the positioning mark is used to calibrate a step measuring instrument, the center of the step measuring instrument's field of view is located at the intersection of the T-line, crosshair, or triangle. That is, during the positioning process, the position of the step height standard block can be adjusted so that the directional intersection of the positioning mark in positioning area 201 is aligned with the center of the step measuring instrument's field of view.

[0041] In some embodiments, the positioning area 201 includes two positioning marks that are symmetrically distributed around the center, and one side of the positioning mark is parallel to the first direction, so that when using the step height standard block for calibration, its placement is not limited. That is, regardless of whether the step measuring instrument is controlled to scan from left to right or from right to left in the first direction, the relative position of the center of the field of view and the stylus of the step measuring instrument can be determined, thereby determining the scanning starting point of the stylus.

[0042] In this embodiment, the coarse calibration area 202 includes at least one raised and / or recessed first position calibration structure relative to the calibration plate 20. The steps of the first position calibration structure include at least three step edges, namely a first step edge, a second step edge, and a third step edge, wherein the first step edge is parallel to the first direction; the second step edge and the third step edge are not parallel to each other and are not parallel to the first direction. The first direction here is a preset scanning direction of the stylus, such as a horizontal direction. When the stylus scans the first position calibration structure, the stylus will output a first measurement result, wherein the first measurement result includes at least two first step signals related to the first position calibration structure. The first measurement result is used to perform preliminary calibration of the step measuring instrument. That is, the coarse calibration area 202 is used to perform preliminary calibration of the step measuring instrument based on the measurement results of the height and surface treatment of the first position calibration structure.

[0043] Specifically, when the stylus scans the first position calibration structure along a determined scanning direction, the step measuring instrument obtains a first measurement result representing the movement of the stylus on the surface of the first position calibration structure. The first measurement result contains at least two step signals. That is, regardless of whether the first position calibration structure is convex or concave, the first measurement result obtained must contain an ascending step signal and a descending step signal. When the center of the field of view and the scanning starting point of the stylus are determined to be the same, since the positional relationship between the first position calibration structure and the positioning mark is determined, when scanning the first position calibration structure, the deviation between the center of the field of view and the stylus (in the second direction, the second direction being the direction perpendicular to the first direction on the plane of the calibration plate 20) has a corresponding relationship with the distance between the ascending step signal and the descending step signal. Therefore, during the calibration process, the stylus is controlled to scan the first position calibration structure along the determined scanning direction, and the distance between the ascending step signal and the descending step signal in the actual first measurement result is compared with the theoretical value. In this way, the deviation between the center of the field of view of the step measuring instrument and the scanning starting point of the stylus can be determined, thereby completing the preliminary calibration of the step measuring instrument.

[0044] In some embodiments, the upper plane of the first position calibration structure within the coarse calibration area 202 may be triangular, semicircular, rectangular, or any irregular shape, that is, the cross-section of the first position calibration structure may be triangular, semicircular, or any irregular shape when viewed from above. It is understood that the stylus is controlled to use different positions in the second direction as the scanning starting point, and the stylus is controlled to start scanning along the first direction. Since the shape of the upper plane of the first position calibration structure is not rectangular, that is, scanning is started from different positions in the second direction, the cross-sectional length of the first position calibration structure obtained is different. Based on the different measurement results obtained, the deviation value between the center of the field of view and the scanning starting point of the stylus can be determined. Preferably, the upper plane of the first position calibration structure is triangular, and the deviation value between the center of the field of view and the scanning starting point of the stylus can be determined by trigonometric functions, the scanning direction, and the positional relationship of the first position calibration structure.

[0045] Figure 2 This is a top view of the structure of the rough calibration area provided in one embodiment of the present application. Figure 2 As shown, in this embodiment, the coarse calibration area 202 includes an auxiliary position calibration structure. The auxiliary position calibration structure includes at least one raised or recessed step relative to the calibration plate 20. At least one step edge of the step structure is parallel to the second step edge or the third step edge of the first position calibration structure. That is, one side of the step of the auxiliary position calibration structure is parallel to one side of the first position calibration structure and is not parallel to the first direction. When the stylus scans the auxiliary position calibration structure, the stylus outputs an auxiliary measurement result. The auxiliary measurement result includes an auxiliary step signal associated with the auxiliary position calibration structure. The auxiliary measurement result is used to calibrate whether the scanning direction of the stylus is parallel to the first direction. That is, the auxiliary position calibration structure is used to determine whether the scanning direction of the stylus is parallel to the first direction based on the measurement results of the height and surface treatment of the scanning auxiliary structure.

[0046] Specifically, for the structure of the determined coarse calibration area 202, the distance between the two parallel sides of the auxiliary position calibration structure and the first position calibration structure should be constant. If the scanning direction of the stylus is parallel to the first direction, the distance value corresponding to the two sides in the step signal can be obtained based on the scanning measurement results to determine whether the scanning direction of the stylus is parallel to the first direction.

[0047] Figure 3 This is a top view of the structure of the first position calibration structure provided by an embodiment of the present application. Figure 3As shown, in this embodiment, the first position calibration structure within the coarse calibration area 202 includes two raised and / or recessed isosceles right triangles relative to the calibration plate 20. Each of the two isosceles right triangles has a right-angled side parallel to the first direction, and the two isosceles right triangles are centrally symmetrically distributed. In this case, the stylus uses different positions in the second direction (a second direction perpendicular to the first direction) as scanning starting points. When scanning along the first direction, after completely passing through the first position calibration structure, the difference between the distance between the rising step signal and the falling step signal in the first measurement result obtained and the theoretical value is the deviation value between the current field of view center and the stylus scanning starting point in the second direction. It can be seen that the isosceles right triangle structure facilitates the calculation of the deviation value between the field of view center and the stylus scanning starting point. At the same time, since the two isosceles right triangles in the first position calibration structure are distributed symmetrically around the center, when the step height standard block is used for calibration, its placement position is not limited. That is, regardless of whether the step measuring instrument is controlled to scan from left to right or from right to left in the first direction, the deviation value between the center of the field of view and the scanning starting point of the probe can be determined.

[0048] like Figure 3 As shown in (a), in some embodiments, the first position calibration structure includes two raised and / or recessed isosceles right triangles relative to the calibration plate 20, with two right-angled sides parallel to the first and second directions, respectively, and the hypotenuses of the two isosceles right triangles are parallel and oppositely disposed. The stylus uses different positions in the second direction as scanning starting points. When scanning along the first direction, after completely passing through the first position calibration structure, the deviation between the current field of view center and the stylus scanning starting point in the second direction can be obtained based on the measurement results. Furthermore, because the hypotenuses of the two isosceles right triangles are parallel and oppositely disposed, the position of the first position calibration structure is fixed for a given step height standard block. That is, for the isosceles right triangle structure, regardless of the scanning starting point in the second direction, the distance from the stylus contacting the right-angled side parallel to the second direction is fixed. Therefore, the deviation between the current field of view center and the stylus scanning starting point in the first direction can be obtained based on the distance difference between the starting point of contact with the first position calibration structure and the first appearance of the step signal.

[0049] based on Figure 3 In the first position calibration structure shown in (a), since the hypotenuses of the two isosceles right triangles are not parallel to the first direction, the hypotenuses of the two isosceles right triangles can be used as the above-mentioned auxiliary position calibration structure. The distance difference between the rising step signal and the falling step signal corresponding to the two hypotenuses in the scanned signal can be used to determine whether the scanning direction of the probe is parallel to the first direction.

[0050] like Figure 3As shown in (b), in some embodiments, the two right-angled sides of the two isosceles right triangles of the first position calibration structure are parallel to the first direction and the second direction, respectively, and the hypotenuses are arranged perpendicularly to each other. Similarly, the deviation value in the first direction between the current field of view center and the scanning starting point of the stylus can also be obtained based on the distance difference obtained from the scanning starting point of the contact with the first position calibration structure to the appearance of the rising step signal and / or the falling step signal.

[0051] In some embodiments, for a determined step height standard sample, the positions of the positioning area 201 and the coarse calibration area 202 on the calibration plate 20 are determined, that is, the distance between the positioning mark and the first position calibration structure is determined. Therefore, based on the distance difference from the positioning mark to the first appearance of the step signal in the signal obtained by scanning the first position calibration structure, the deviation value between the current field of view center and the scanning starting point of the probe in the first direction is determined.

[0052] like Figure 1 As shown, in this embodiment, the fine calibration area 203 is located between the positioning area 201 and the coarse calibration area 202. The fine calibration area 203 includes at least one second position calibration structure that is raised and / or recessed relative to the calibration plate 20. The second position calibration structure is smaller than the first position calibration structure. When the stylus scans the second position calibration structure, the stylus outputs a second measurement result. The second measurement result includes at least two second step signals associated with the second position calibration structure. The second measurement result is used to perform a secondary calibration of the step measuring instrument. In other words, after completing the initial calibration of the step measuring instrument, the fine calibration area 203 is used to accurately calibrate the step measuring instrument based on the height and surface treatment measurement results of the second position calibration structure. If the relative position error between the center of the field of view of the step measuring instrument and the starting point of the stylus scanning calibrated in the early stage is large, even if the center of the field of view is aligned with the directional intersection of the positioning area, the stylus may not scan the second position calibration structure during the scanning process. Therefore, the first position calibration structure can be used to preliminarily calibrate the relative position of the center of the field of view of the step measuring instrument and the starting point of the stylus scanning, and preliminarily obtain a relative position with a certain degree of accuracy. Then, in the subsequent process, the stylus is made to scan the second position calibration structure to obtain a high-precision relative position.

[0053] Specifically, when the stylus scans to the second position calibration structure along a determined scanning direction, the step measuring instrument obtains a second measurement result representing the movement of the stylus on the surface of the second position calibration structure. The second measurement result contains at least two step signals, that is, regardless of whether the second position calibration structure is convex or concave, the obtained second measurement result must contain an ascending step signal and a descending step signal. When the center of the field of view and the scanning starting point of the stylus are determined to be the same, since the second position calibration structure is determined, when scanning the second position calibration structure, the distance between the ascending step signal and the descending step signal in the second measurement result can be determined in advance. Therefore, during the calibration process, the stylus is controlled to scan the second position calibration structure along the determined scanning direction, and the distance between the ascending step signal and the descending step signal in the actually obtained second measurement result is compared with the theoretical value. The deviation between the center of the field of view of the step measuring instrument and the scanning starting point of the stylus can be determined, thereby completing the secondary calibration of the step measuring instrument. At the same time, because the size of the second position calibration structure is smaller than the first position calibration structure, a more precise alignment scan is required during the scanning process. The second measurement result obtained is more accurate than the first measurement result, so it can be regarded as a secondary calibration of the step measuring instrument.

[0054] In the coarse calibration area 202, for the larger first position calibration structure, the deviation between the center of the field of view and the starting point of the stylus scanning is easily obtained during the calibration process, resulting in a certain error. For some step measuring instruments that require high-precision calibration, the calibration accuracy may not meet the requirements. For the smaller first position calibration structure, during the calibration process, the relative position of the center of the field of view and the stylus may be far apart, making it impossible to scan the first position calibration structure. Therefore, a fine calibration area 203 is set between the positioning area 201 and the coarse calibration area 202. When calibrating the step measuring instrument, the first calibration is first performed using the first position calibration structure in the coarse calibration area 202 to reduce the relative position between the center of the field of view and the starting point of the stylus scanning. Then, a second calibration is performed using the second position calibration structure in the fine calibration area 203 to improve calibration accuracy.

[0055] In some embodiments, the positioning mark of the positioning area 201, the first position calibration structure of the coarse calibration area 202, and the second position calibration structure of the fine calibration area 203 are symmetrically distributed about the same position center, so that when using the step height standard block for calibration, their placement position is not limited, that is, regardless of whether the step measuring instrument is controlled to scan from left to right or from right to left in the first direction, the relative position of the center of the field of view and the stylus of the step measuring instrument can be determined.

[0056] In some embodiments, the second position calibration structure within the calibration area is identical to the first position calibration structure within the coarse calibration area 202. Specifically, the upper plane of the second position calibration structure can be triangular, semicircular, rectangular, or any irregular shape. Furthermore, the cross-section of the first position calibration structure, viewed from a top view, can be triangular, semicircular, or any irregular shape. A step signal is obtained by scanning the second position calibration structure, and the deviation between the center of the step measuring instrument's field of view and the stylus scanning starting point is determined based on the distance between the ascending and descending steps in the step signal. The specific process is identical to the calibration process for scanning the first position calibration structure and is not further described here.

[0057] Preferably, the second position calibration structure includes two raised and / or recessed isosceles right triangles, each of the two isosceles right triangles has a right-angled side parallel to the first direction, and the hypotenuses of the two isosceles right triangles are arranged parallel to each other or perpendicular to each other, which is the same as the first position calibration structure.

[0058] In summary, the step height standard block for calibrating the measurement accuracy of a step measuring instrument provided in an embodiment of the present application includes a substrate 10 and a calibration plate 20 for calibrating the position of a stylus arranged on the substrate 10, and the calibration plate 20 is provided with a positioning area 201, a coarse calibration area 202 and a fine calibration area 203; wherein, the positioning mark is a directional positioning mark, which is used to indicate the relative position of the field of view center of the step measuring instrument and the stylus, and the coarse calibration area 202 and the fine calibration area 203 each include at least one raised and / or recessed position calibration structure relative to the calibration plate 20, wherein the position calibration structure of the fine calibration area 203 is smaller than the position calibration structure of the coarse calibration area 202; when the stylus of the step measuring instrument scans to the position calibration structure of different areas, it will output a step signal related to the position calibration structure, and at least one fine calibration of the step measuring instrument can be completed according to the step signal.

[0059] This application first uses the positioning mark of the positioning area 201 and the position calibration structure of the coarse calibration area 202 to calibrate the step measuring instrument, determines the relative position between the center of the field of view and the scanning starting point of the probe, reduces the error caused by the deviation of the scanning starting point, and then accurately calibrates the step measuring instrument through the position calibration structure of the fine calibration area 203, thereby improving the calibration accuracy and ensuring the accuracy and reliability of the measurement results of the step measuring instrument.

[0060] Figure 4 This is a top view of the structure of a step height standard sample block provided in another embodiment of the present application. Figure 4As shown, the step height standard block for calibrating and correcting the step measuring instrument provided in this embodiment includes a substrate 10 and a calibration plate 20 arranged on the substrate 10 for calibrating the position of the stylus, wherein the calibration plate 20 is provided with the positioning area 201, the rough calibration area 202, and the fine calibration area 203 described in any of the above embodiments, and also includes at least one of the step height calibration area 204 and the stylus defect recognition area 205. Therefore, by arranging multiple different innovative calibration structures on the step height standard block, different calibration items can be realized, and then the calibration program can be set to complete various and complete calibration items, realizing "one-click calibration" and simplifying the calibration operation.

[0061] In this embodiment, the step height calibration area 204 includes a third position calibration structure that is raised and / or recessed relative to the calibration plate 20 to ensure the accuracy of the step height calibration. In some embodiments, one step edge of the third position calibration structure can be parallel to the first direction. In some embodiments, the upper plane of the third position calibration structure can be rectangular, with one side of the rectangle parallel to the first direction.

[0062] Stylus defect identification area 205 includes a fourth position calibration structure with projections or depressions at different locations forming different angles with the first direction. In some embodiments, the upper surface of the fourth position calibration structure has a curved pattern with different slopes with respect to the first direction. When the stylus scans the fourth position calibration structure, the stylus outputs a fourth measurement result, which includes a fourth step signal associated with the fourth position calibration structure. The fourth measurement result is used to identify defects in the stylus. Specifically, stylus defect identification area 205 is used to determine whether the stylus of the step measuring instrument has a defect based on the height measurement result of the fourth position calibration structure.

[0063] It is understandable that because the fourth position calibration structure has raised or recessed steps that form different angles with the first direction at different locations, when the stylus scans along the first direction, the locations where the stylus contacts the fourth position calibration structure are different, resulting in different intensities of the step signals obtained. When the stylus does not have defects, it can contact the fourth position calibration structure in every orientation when scanning the fourth position calibration structure, and the step signals in each orientation should be relatively clear. If a defect occurs in one orientation of the stylus, such as a missing corner or contamination with other substances, when the stylus scans the fourth step, the signals obtained at the defective orientation and the fourth step contact surface at other orientations will be different, and the step signal will be abnormal. In other words, the scanning results can be used to determine whether the stylus of the step measuring instrument has defects.

[0064] Figure 5 This is a top view of the fourth position calibration structure provided in one embodiment of the present application. Figure 5As shown, in this embodiment, the upper surface of the fourth position calibration structure can be formed of multiple circular rings and / or semicircular rings. Because the slopes of the circular rings or semicircular rings vary, the measurement orientation can be changed by changing the position of the stylus scanning starting point in the second direction. In other words, using a curved fourth position calibration structure allows the stylus to measure a wider range of angles.

[0065] During the scanning process, the stylus contacts the stylus defect recognition structure at different positions, with contact points in different directions, perpendicular to the tangent direction of the contact position. Two different locations are selected in the second direction as the scanning starting points. For a scanning path away from the center of the semicircle, the stylus can scan angles of -45°, 135°, -30°, 120°, 0°, and 180°. For a scanning path close to the center of the semicircle, the stylus can scan angles of -60°, 150°, -50°, 140°, 0°, and 180°. In other words, when a stylus defect may exist, the scanning curve-shaped fourth position calibration structure is used to determine the location of the abnormal step signal obtained by scanning, and the corresponding scanning contact angle of the stylus is determined, thereby determining the location of the stylus defect.

[0066] It should be noted that the heights of the protrusions and depressions in the first position calibration structure in the coarse calibration area 202, the second position calibration structure in the fine calibration area 203, the third position calibration structure in the step height calibration area 204, and the fourth position calibration structure in the stylus defect identification area 205 are not identical. It is understood that the heights of the different position calibration structures simply respond to the intensity of the corresponding step signal obtained by the stylus scanning. When determining the accuracy of the calibrated step measuring instrument based on the scanning results, the distance corresponding to the step in the step signal is used, which has no direct relationship with the signal intensity. Therefore, the heights of the various position calibration structures can be the same or different.

[0067] Figure 6 This is a structural diagram of a step height standard sample block provided in another embodiment of the present application. Figure 6 As shown, the step height standard sample block for calibrating the step measuring instrument provided in this embodiment includes a substrate 10 and a calibration plate 20 arranged on the substrate 10 for calibrating the position of the stylus, wherein the calibration plate 20 is provided with the positioning area 201, the rough calibration area 202, the fine calibration area 203, the step height calibration area 204, the stylus defect recognition area 205 and the linear calibration area 206 described in any of the above embodiments.

[0068] It is understandable that during the preparation process of the step measuring instrument, factors such as processing errors, assembly errors, and structural deformation may have a nonlinear effect on the measurement results of the step measuring instrument. Specifically, when scanning a plane, the measured signal is not a straight line, but a fluctuating curve. Therefore, the step measuring instrument needs to be linearly calibrated.

[0069] In this embodiment, linear calibration region 206 includes a plane at an angle to substrate 10 and is used to perform linear calibration on the step measuring instrument. Specifically, when the stylus scans linear calibration region 206, since linear calibration region 206 is a plane at an angle to substrate 10, the stylus scanning measurement results are used to determine whether the step measuring instrument is affected by nonlinearity. Specifically, if the step signal obtained when the stylus scans linear calibration region 206 is a fluctuating curve rather than a straight line, this indicates that the step measuring instrument is affected by nonlinearity and requires further inspection for assembly issues.

[0070] Figure 7 This is a structural diagram of a step height standard sample block provided in another embodiment of the present application. Figure 7 As shown, the step height standard block provided in this embodiment for calibrating a step measuring instrument includes a base plate 10, a calibration plate 20 disposed on the base plate 10 for calibrating the position of a stylus, and a detachable protective cover 30 for protecting the calibration plate 20. The protective cover 30 forms a sealed space with the base plate 10, completely covering the calibration plate 20 and protecting the step structures of the calibration areas on the calibration plate 20 from dust and wear.

[0071] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make several simple deductions, modifications or replacements based on the ideas of the present application without departing from the scope of protection of the purpose of the present application and the claims. All of these are within the protection of the present application.

Claims

1. A step height standard block for calibrating a step measuring instrument, characterized in that: It comprises a substrate and a calibration plate provided on the substrate for calibrating the position of the stylus; the calibration plate is provided with a positioning area, a rough calibration area and a fine calibration area; The positioning area includes at least one positioning mark for indicating the starting point of the stylus scanning; the coarse calibration area includes at least one first position calibration structure that is raised and / or recessed relative to the calibration plate; the fine calibration area is located between the positioning area and the coarse calibration area; the fine calibration area includes at least one second position calibration structure that is raised and / or recessed relative to the calibration plate, and the size of the second position calibration structure is smaller than that of the first position calibration structure.

2. The step height standard block according to claim 1, characterized in that: The positioning mark is a pattern with a directional intersection, and the pattern with a directional intersection is any one of a T-line, a cross line or a triangle line, and the center of the field of view of the step measuring instrument is located at the intersection of the T-line, the cross line or the triangle line; The positioning mark, the first position calibration structure and the second position calibration structure are symmetrically distributed about the same position center.

3. The step height standard block according to claim 1, characterized in that: The step of the first position calibration structure in the coarse calibration area includes at least three step edges, namely a first step edge, a second step edge, and a third step edge; the first step edge is parallel to a first direction; the second step edge and the third step edge are not parallel to each other and are not parallel to the first direction; wherein the first direction is a preset scanning direction of the stylus; The second position calibration structure in the fine calibration area is the same as the first position calibration structure in the coarse calibration area; The coarse calibration area also includes an auxiliary position calibration structure; the auxiliary position calibration structure includes a raised and / or recessed step relative to the calibration plate, and at least one step edge of the step is parallel to the second step edge or the third step edge.

4. The step height standard block according to claim 3, characterized in that: The first position calibration structure includes two isosceles right triangles that are raised and / or recessed relative to the calibration plate, the hypotenuses of the two isosceles right triangles are parallel and arranged opposite to each other, and each of the two isosceles right triangles has a right-angled side parallel to the first direction; Alternatively, the first position calibration structure includes two isosceles right triangles that are raised and / or recessed relative to the calibration plate, the hypotenuses of the two isosceles right triangles are arranged perpendicularly relative to each other, and each of the two isosceles right triangles has a right-angled side parallel to the first direction.

5. The step height standard block according to claim 1, characterized in that: The calibration plate is also provided with a step height calibration area; The step height calibration area includes a third position calibration structure that is raised and / or recessed relative to the calibration plate.

6. The step height standard block according to claim 3, characterized in that: The calibration plate is also provided with a stylus defect recognition area; The stylus defect recognition area includes a fourth position calibration structure having protrusions or depressions at different locations forming different angles with the first direction.

7. The step height standard block according to claim 6, characterized in that: The upper plane of the fourth position marking structure is a pattern with curves, and the pattern with curves is a plurality of circular rings and / or semicircular rings.

8. The step height standard block according to claim 6, characterized in that: The heights of the protrusions or depressions of the first position marking structure, the second position marking structure, the third position marking structure, and the fourth position marking structure are not completely the same.

9. The step height standard block according to claim 1, characterized in that: It also includes a linear calibration area arranged on the substrate; the linear calibration area includes a plane with an angle with the substrate, which is used to perform linear calibration on the step measuring instrument.

10. The step height standard block according to claim 1, characterized in that: It also includes a detachable protective cover arranged on the base plate; the calibration plate is located in the protective cover.

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