Film thickness standard sheets and their preparation methods, and calibration methods for film thickness measuring equipment.

Abstract

This invention provides a film thickness standard sheet, its preparation method, and a calibration method for a film thickness measuring device. In this film thickness standard sheet, grooves and / or protrusions are formed on a substrate, and a thin film layer covers these grooves and / or protrusions. This allows for accurate determination of the film thickness value on the standard sheet based on the dimensional changes of the grooves and / or protrusions before and after covering the film layer, thus meeting the requirements of a standard sheet. The film thickness standard sheet provided by this invention can be directly prepared using existing equipment, significantly reducing the cost of the standard sheet. Furthermore, when at least two calibration areas of different thickness levels are simultaneously formed on the standard sheet, multiple calibration processes with different thicknesses can be performed using the same standard sheet, further saving on standard sheet expenses. It also avoids the need to change multiple standard sheets, improving the calibration efficiency of the equipment and reducing the risk of breakage during sheet changes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a film thickness standard wafer and its preparation method, as well as a calibration method for film thickness measuring equipment. Background Technology

[0002] In the semiconductor manufacturing process, thin film layers are deposited on substrates using physical or chemical methods, followed by photolithography, etching, and other processes to form circuit structures. After thin film deposition, the substrate is typically transferred to a thickness measurement device for testing to determine the thickness of the thin film layer. Therefore, the thickness measurement device plays a crucial role, and ensuring its accuracy is paramount. This accuracy can generally be guaranteed through regular calibration of the equipment.

[0003] Specifically, when calibrating a film thickness measurement device, a standard sheet is required. This standard sheet has a thin film layer of a predetermined thickness formed on it. The film thickness measurement device measures the thickness of the thin film layer on the standard sheet, and the measured value is compared with the standard value for the thickness of the thin film layer to determine whether the device has high measurement accuracy. Currently, the standard sheets used generally need to be purchased separately, and they are expensive. In addition, multiple standard sheets of different thickness grades are usually provided so that the film thickness measurement device has corresponding standard sheets for calibration when performing calibration processes for various thicknesses, thereby ensuring the accuracy of the measurement device. However, using multiple standard sheets for calibration not only incurs high costs, but also requires multiple loading and unloading of each standard sheet, wasting time, reducing machine output, and increasing the risk of standard sheet damage during transportation. Summary of the Invention

[0004] The purpose of this invention is to provide a film thickness standard sheet and its preparation method, so as to solve the problem of the high price of the currently used film thickness standard sheets.

[0005] To address this, the present invention provides a film thickness standard sheet, comprising: a substrate and a thin film layer formed on the substrate, the substrate having at least one calibration region, and the thin film layer at least covering the calibration region. Specifically, at least one groove is formed within the calibration region of the substrate, the groove having a first opening size, the thin film layer covering the groove and the top surface of the substrate, the thin film layer covering the groove reducing the opening region of the groove to a second opening size, and the thickness value of the thin film layer being obtained based on the difference between the first opening size and the second opening size; and / or, at least one protrusion is formed within the calibration region of the substrate, the protrusion having a first width size, the thin film layer covering the protrusion and the top surface of the substrate, the thin film layer covering the protrusion forming a second width size, and the thickness value of the thin film layer being obtained based on the difference between the second width size and the first width size.

[0006] Optionally, at least two grooves are formed in the calibration area of ​​the substrate, and the substrate forms a first protrusion of the at least one protrusion corresponding to the portion between two adjacent grooves.

[0007] Optionally, the groove and the protrusion are formed in the calibration region of the substrate, a first thickness value is obtained based on the first opening size and the second opening size, a second thickness value is obtained based on the first width size and the second width size, and the thickness value of the thin film layer is obtained based on the average of the first thickness value and the second thickness value.

[0008] Optionally, the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold.

[0009] Optionally, the at least one protrusion includes a second protrusion that protrudes from the top surface of the substrate.

[0010] Optionally, the sidewall inclination of the groove is 85°-95°; and / or, the sidewall inclination of the protrusion is 85°-95°.

[0011] Optionally, the substrate has at least two calibration regions, and the thickness of the thin film layer formed in at least a portion of the calibration regions is different from that of the others.

[0012] Optionally, the substrate has at least two calibration regions, wherein a portion of the calibration region is located in the central region of the substrate, and another portion of the calibration region is located in the edge region of the substrate.

[0013] The present invention also provides a method for preparing a film thickness standard sheet, comprising the following steps: First step, providing a substrate, wherein at least one calibration region is defined on the substrate. Second step, forming at least one groove within the calibration region of the substrate and obtaining a first opening size of the groove; and / or, forming at least one protrusion within the calibration region of the substrate and obtaining a first width size of the protrusion. Third step, forming a thin film layer on the substrate, the thin film layer at least covering the calibration region; wherein, when a groove is formed within the calibration region, obtaining a second opening size of the opening region of the groove after covering the thin film layer; and when a protrusion is formed within the calibration region, obtaining a second width size of the protrusion after covering the thin film layer. Fourth step, obtaining a thickness value of the thin film layer based on the difference between the first opening size and the second opening size, and / or the difference between the second width size and the first width size.

[0014] Optionally, at least two grooves are formed in the substrate, and a first protrusion of the at least one protrusion is formed in the portion of the substrate corresponding to the space between adjacent grooves.

[0015] Optionally, the substrate has the groove and the protrusion formed in the calibration area, and after obtaining the first thickness value based on the first opening size and the second opening size, and obtaining the second thickness value based on the first width size and the second width size, the method further includes: determining whether the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold; if yes, the formed thin film layer meets the requirements of the standard sheet, and the thickness value of the thin film layer is obtained based on the first thickness value and the second thickness value; if no, rework is performed to reformat the thin film layer until the absolute value of the difference between the obtained first thickness value and the second thickness value is less than or equal to the preset threshold.

[0016] Optionally, the at least one protrusion includes a second protrusion that protrudes from the top surface of the substrate.

[0017] Optionally, the substrate has at least two calibration regions, and the thickness of the thin film layer formed in at least a portion of the calibration regions is different from that of the others.

[0018] Optionally, the at least two calibration regions include a first calibration region and a second calibration region. A first thin film layer is formed in the first calibration region, and a second thin film layer is formed in the second calibration region. The method for forming a second thin film layer includes: forming at least one groove and / or at least one protrusion in each calibration region of the substrate; forming a first thin film layer in the first calibration region and obtaining the thickness value of the first thin film layer; and forming a second thin film layer in the second calibration region and obtaining the thickness value of the second thin film layer.

[0019] Optionally, the sidewall inclination of the groove is 85°-95°; and / or, the sidewall inclination of the protrusion is 85°-95°.

[0020] The present invention also provides a calibration method for a film thickness measuring device, comprising: providing a film thickness standard sheet as described above; using a film thickness measuring device to measure the thickness of a thin film layer on the film thickness standard sheet to obtain a thickness measurement value of the thin film layer on the standard sheet; and comparing the thickness measurement value of the thin film layer with the standard value of the thickness of the thin film layer to determine whether the film thickness measuring device is malfunctioning.

[0021] Optionally, the film thickness standard sheet has at least two calibration areas; the film thickness measuring device first measures the thickness of the film layer in one of the calibration areas, and then moves the measurement point to another calibration area and measures the thickness thereon, so as to achieve a calibration process for different thicknesses.

[0022] The present invention also provides a method for obtaining film thickness, comprising the following steps: Step 1, forming at least one groove on a substrate and obtaining a first opening size of the groove; and / or, forming at least one protrusion on the substrate and obtaining a first width size of the protrusion. Step 2, forming a thin film layer on the substrate, wherein when a groove is formed on the substrate, the thin film layer covers the groove, and obtaining a second opening size of the opening area of ​​the groove after covering the thin film layer; and, when a protrusion is formed on the substrate, the thin film layer covers the protrusion, and obtaining a second width size of the protrusion after covering the thin film layer. Step 3, obtaining the thickness value of the thin film layer based on the difference between the first opening size and the second opening size, and / or the difference between the second width size and the first width size.

[0023] Optionally, at least two grooves are formed in the substrate, and a first protrusion of the at least one protrusion is formed in the portion of the substrate corresponding to the space between adjacent grooves.

[0024] Optionally, the substrate has the groove and the protrusion formed thereon, and after obtaining the first thickness value based on the first opening size and the second opening size, and obtaining the second thickness value based on the first width size and the second width size, the method further includes: determining whether the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold; if so, obtaining the thickness value of the thin film layer based on the average value of the first thickness value and the second thickness value.

[0025] Optionally, the sidewall inclination of the groove is 85°-95°; and / or, the sidewall inclination of the protrusion is 85°-95°.

[0026] In the film thickness standard sheet provided by this invention, by forming grooves and / or protrusions on a substrate and covering the grooves and / or protrusions with a thin film layer, the thickness value of the thin film layer on the standard sheet can be accurately obtained based on the dimensional changes of the grooves and / or protrusions before and after covering the thin film layer, thus meeting the requirements of a standard sheet. Furthermore, this invention converts the longitudinal thickness value of the thin film layer into the lateral dimensional changes of the grooves and / or protrusions before and after covering the thin film layer. Compared with traditional film thickness measurement methods, the film thickness measurement method provided by this invention not only accurately obtains the film thickness value but also reduces the difficulty of thickness measurement. In addition, the film thickness standard sheet provided by this invention can be directly prepared using existing equipment, greatly reducing the cost of the standard sheet.

[0027] Furthermore, at least two calibration areas of different thickness levels can be set on the same standard sheet, so that the film thickness measurement equipment can perform multiple calibration processes of different thicknesses based on the same standard sheet during calibration. Compared with the traditional calibration process that requires multiple standard sheets to perform different thicknesses, the present invention only requires one standard sheet to complete the process, which can effectively save the cost of standard sheets. At the same time, it also avoids the process of loading and unloading multiple standard sheets one by one, improves the calibration efficiency of the equipment, and reduces the risk of sheet breakage that may be caused during the sheet replacement process.

[0028] Furthermore, the technical concept provided by this invention, which uses the dimensional changes of grooves and / or protrusions before and after covering the thin film layer to obtain the thickness value of the thin film layer, can also be directly applied to semiconductor processing to accurately obtain the thickness of the thin film layer during its fabrication. Moreover, the thickness difference between the thin film layer covering the grooves and protrusions can be used to achieve real-time monitoring of the uniformity of the currently formed thin film layer, and this can further reflect the performance of the thin film deposition equipment used and determine whether any abnormalities exist. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a film thickness standard sheet in one embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram showing the distribution of multiple calibration regions of a film thickness standard sheet in one embodiment of the present invention.

[0031] Figure 3 This is a schematic flowchart of a method for preparing a film thickness standard sheet according to an embodiment of the present invention.

[0032] Figures 4-5 This is a schematic diagram of the structure of a film thickness standard sheet in the preparation process of an embodiment of the present invention. Detailed Implementation

[0033] The core idea of ​​this invention is to provide a film thickness standard sheet, in which the thickness of the thin film layer can be accurately obtained to meet the requirements of the standard sheet. This standard sheet can be directly prepared using existing equipment, thereby reducing the cost of the standard sheet.

[0034] Specifically, the film standard sheet provided by the present invention includes a substrate and a thin film layer formed on the substrate. The substrate has at least one calibration region, and the thin film layer at least covers the calibration region of the substrate. Specifically, at least one groove is formed within the calibration region of the substrate, the groove having a first opening size. The thin film layer covers the groove and the top surface of the substrate, reducing the opening area of ​​the groove to a second opening size. The thickness value of the thin film layer is obtained based on the difference between the first opening size and the second opening size. And / or, at least one protrusion is formed within the calibration region of the substrate, the protrusion having a first width dimension. The thin film layer covers the sidewalls of the protrusion and the top surface of the substrate, covering the protrusion to form a second width dimension. The thickness value of the thin film layer is obtained based on the difference between the second width dimension and the first width dimension.

[0035] That is, the film standard sheet provided by the present invention utilizes the dimensional changes of the grooves and / or protrusions before and after covering the film layer to accurately obtain the thickness value of the film layer on the standard sheet, so that the standard sheet meets the requirements for equipment calibration.

[0036] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the film thickness standard sheet and its preparation method, as well as the calibration method for the film thickness measuring device proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of the invention. It should be understood that relative terms such as "above," "below," "top," "bottom," and "upper" shown in the drawings can be used to describe the relationships between various elements. These relative terms are intended to cover different orientations of elements other than those depicted in the drawings. For example, if the device is inverted relative to the view in the drawings, an element described, for example, as being "above" another element would now be below that element.

[0037] Figure 1 This is a schematic diagram of the structure of a film thickness standard sheet in one embodiment of the present invention, as shown below. Figure 1 As shown, the film thickness standard sheet includes a substrate 100 and a thin film layer 200 formed on the substrate 100. The substrate 100 has at least one calibration region, and the thin film layer at least covers the calibration region of the substrate 100, for example... Figure 2The diagram illustrates that nine calibration regions are formed on the substrate 100. Furthermore, the thin film layer 200 can be an insulating dielectric layer (e.g., a silicon nitride layer or a silicon oxide layer) or a conductive layer (e.g., a metal layer).

[0038] In one alternative embodiment, at least one groove 110 is formed in the calibration region of the substrate 100, the groove 110 having a first opening size SCD1. The thin film layer 200 covers the groove 110 and the top surface of the substrate 100, and after the thin film layer 200 is applied, the opening size of the groove 110 is reduced to a second opening size SCD2. Therefore, the thickness value THK of the thin film layer 200 can be obtained based on the difference between the first opening size SCD1 and the second opening size SCD2. Specifically, the thin film layer 200 conforms to the inner surface of the groove 110 and covers the bottom surface and sidewalls of the groove 110. The thickness of the thin film layer 200 covering the sidewalls of the groove is the same as the thickness of the thin film layer 200 covering the top surface of the substrate. Therefore, the thickness value THK of the thin film layer 200 can be obtained based on the first opening size SCD1 and the second opening size SCD2 of the groove 110 before and after the thin film layer 200 is applied, specifically THK = (SCD1 - SCD2) / 2.

[0039] That is, in this solution, by obtaining the difference in opening size of the groove 110 before and after covering the thin film layer 200, the thickness value of the thin film layer 200 can be accurately obtained, which can be used as a standard sheet for film thickness measurement. This standard sheet can then be used to monitor and calibrate the film thickness measurement equipment. Furthermore, the thin film layer 200 at least covers the top surface of the substrate around the outer periphery of the groove 110. The portion of the thin film layer 200 covering the top surface of the substrate can, for example, be used as a thickness measurement point during the calibration of the film thickness measurement equipment.

[0040] In another alternative embodiment, at least one protrusion 120 is formed in the calibration region of the substrate 100. The protrusion 120 has a first width dimension LCD1. The thin film layer 200 covers the protrusion 120 and the top surface of the substrate 100. The thin film layer 200 covers the protrusion 120, increasing the width dimension to a second width dimension LCD2. The thickness value THK of the thin film layer 200 is obtained based on the difference between the second width dimension LCD2 and the first width dimension LCD1. Specifically, the thin film layer 200 conforms to the outer surface of the protrusion 120 and covers the top surface and sidewalls of the protrusion 120. The thickness of the thin film layer 200 covering the sidewalls of the protrusion is the same as the thickness of the thin film layer 200 covering the top surface of the substrate. Therefore, the thickness value THK of the thin film layer 200 can be obtained based on the first width dimension LCD1 and the second width dimension LCD2 of the protrusion 120 before and after covering the thin film layer 200, specifically THK = (LCD2 - LCD1) / 2.

[0041] That is, in this scheme, by obtaining the difference in width of the protrusion 120 before and after covering the thin film layer 200, the thickness value of the thin film layer 200 can be accurately obtained, which can be used as a standard sheet for film thickness measurement. This standard sheet can then be used to monitor and calibrate the film thickness measurement equipment. Furthermore, the thin film layer 200 at least covers the top surface of the substrate around the protrusion 120, and the portion of the thin film layer 200 covering the top surface of the substrate can, for example, be used as a thickness measurement point during the calibration of the film thickness measurement equipment.

[0042] In a specific example, within the same calibration area of ​​the same standard sheet, only a groove 110 may be formed, or only a protrusion 120 may be formed, or both a protrusion 120 and a groove 110 may be formed simultaneously. The protrusion 120 may be formed within the substrate 100 (e.g., the portion between adjacent grooves 110 constitutes a protrusion 120), and a protrusion formed within the substrate 100 may be defined as a first protrusion; alternatively, the protrusion 120 may also protrude beyond the top surface of the substrate 100, and a protrusion protruding beyond the top surface of the substrate may be defined as a second protrusion.

[0043] When both groove 110 and protrusion 120 are formed in the same calibration area, the first opening size SCD1 and the second opening size SCD2 of the groove 110 before and after the covering film layer 200, and the first width size LCD1 and the second width size LCD2 of the protrusion 120 before and after the covering film layer 200 can be obtained simultaneously. At this time, the first thickness value THK1 can be obtained according to the first opening size SCD1 and the second opening size SCD2, and the second thickness value THK2 can be obtained according to the first width size LCD1 and the second width size LCD2. Based on this, the thickness of the film layer 200 can be obtained based on the first thickness value THK1 and the second thickness value THK2.

[0044] Specifically, in an ideal state, the first thickness value THK1, obtained based on the difference between the first opening size SCD1 and the second opening size SCD2, is equal to the second thickness value THK2, obtained based on the difference between the second width size LCD2 and the first width size LCD1. However, in practical applications, the thin film layer 200 on the substrate 100 can be formed by a thin film deposition equipment. The process and equipment may have certain allowable errors, resulting in slight differences in the coverage performance of the groove 110 and the protrusion 120. This ensures that the difference between the thickness of the deposited thin film layer 200 when covering the groove 110 and the thickness when covering the protrusion 120 is within the allowable error range. That is, there is a difference between the first thickness value THK1 obtained based on the difference between the first opening size SCD1 and the second opening size SCD2, and the second thickness value THK2 obtained based on the difference between the second width size LCD2 and the first width size LCD1. The absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is less than or equal to a preset threshold (i.e., |THK1-THK2|≤spec). In this case, the thickness value of the thin film layer 200 can be obtained based on the average value of the first thickness value THK1 and the second thickness value THK2, i.e., THK = (THK1+THK2) / 2.

[0045] Of course, if the thin film deposition equipment malfunctions or the process precision is poor, the thickness of the deposited thin film layer 200 when covering the groove 110 and the thickness when covering the protrusion 120 will differ significantly. This will cause the absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 to exceed a preset threshold (i.e., |THK1-THK2|>spec). Therefore, thickness measurements can be performed based on the groove 110 and the protrusion 120, and the two measurements can be cross-validated to further ensure the accuracy of the obtained thickness of the thin film layer 200. Specifically, when the difference between the first thickness value THK1 obtained based on the groove 110 and the second thickness value THK2 obtained based on the protrusion 120 is still within the threshold range, it means that the coverage performance of the deposited thin film layer 200 is uniform on different patterns. At this time, the first thickness value THK1 and the second thickness value THK2 can more accurately reflect the true thickness of the thin film layer 200. Conversely, when the difference between the first thickness value THK1 and the second thickness value THK2 exceeds the threshold range, it means that the coverage uniformity of the deposited thin film layer 200 is abnormal. At this time, it can also be used to determine whether there is an abnormality in the thin film deposition equipment used.

[0046] exist Figure 1In the example shown, the substrate 100 has at least two grooves 110 formed in the same calibration area, and a protrusion 120 is formed in the substrate 100 corresponding to the portion between two adjacent grooves 110, which can be defined as a first protrusion. The thin film layer 200 covers the sidewalls and bottom surface of the grooves 110, and covers the sidewalls and top surface of the protrusions 120, wherein a portion of the sidewall of the groove 110 corresponds to the sidewall of the protrusion 120. The first thickness value THK1 is obtained based on the first opening size SCD1 and the second opening size of the groove 110 before and after the covering film layer 200. The second thickness value THK2 is obtained based on the first width size LCD1 and the second width size LCD2 of the protrusion 120 before and after the covering film layer 200. The absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is within the range of a preset threshold (i.e., |THK1-THK2|≤spec). The thickness value of the film layer 200 can be obtained based on the average value of the first thickness value THK1 and the second thickness value THK2, i.e., THK = (THK1+THK2) / 2.

[0047] It should be noted that the first opening size SCD1 and the second opening size SCD2 of the groove 110, as well as the first width size LCD1 and the second width size LCD2 of the protrusion 120, can be obtained by scanning electron microscopy (SEM), and more specifically, by critical dimension scanning electron microscopy (CD-SEM) to measure the above dimensions more accurately.

[0048] Furthermore, when a groove 110 is formed in the calibration area of ​​the substrate 100, the inclination of the sidewall of the groove 110 can be between 85° and 95° (i.e., the angle between the sidewall of the groove and the bottom surface of the groove is 85°-95°), so that the sidewall of the groove 110 is a vertical sidewall or a near-vertical sidewall. Similarly, when a protrusion 120 is formed in the calibration area of ​​the substrate 100, the inclination of the sidewall of the protrusion 120 can be between 85° and 95° (i.e., the angle between the sidewall of the protrusion and the top surface of the substrate is between 85° and 95°), so that the sidewall of the protrusion 120 is a vertical sidewall or a near-vertical sidewall. This facilitates more accurate measurement of the opening size of the groove 110 before and after the cover film layer 200, and the width size of the protrusion 120 before and after the cover film layer 200.

[0049] In an optional scheme, at least two calibration regions can be defined on the substrate 100, for example... Figure 2 The diagram illustrates nine calibration regions, where at least some of the thin film layers 200 formed within these regions have varying thicknesses. In a specific example, the standard sheet may have calibration regions of different thicknesses, for example... Figure 2 In the example, the thickness of the thin film layer is different in calibration region 2 and correction region 6. Figure 2In the example, the thickness of the thin film layer in calibration region 4 and calibration region 8 is different, enabling the film thickness measurement device to perform calibration processes for different thicknesses based on the same standard sheet. Furthermore, the standard sheet can also have calibration regions of the same thickness, which can be distributed, for example, in the central and edge regions of the substrate, allowing thickness calibration to be performed on the distribution of the central and edge regions of the standard sheet. For example, the thickness of the thin film layer in calibration region 5 and calibration region 6 is the same. Alternatively, some calibration regions on the standard sheet are located in the central region of the substrate 100, and another portion is located in the edge region of the substrate 100. The thickness of the thin film layer 200 in the calibration regions located in the central region of the substrate 100 can be different or the same; similarly, the thickness of the thin film layer 200 in the calibration regions located in the edge region of the substrate 100 can be different or the same. In addition, each calibration region has a groove 110 and / or a protrusion 120 as described above, so that the thickness value of the thin film layer 200 in the corresponding region can be obtained based on the dimensional changes of the groove 110 and / or protrusion 120 before and after covering the thin film layer 200.

[0050] In other words, this scheme allows multiple calibration areas with different thicknesses to be set on the same standard sheet simultaneously. This enables the calibration of film thickness measurement equipment at different thickness levels using the same standard sheet, overcoming the problem of high costs associated with using multiple standard sheets for different thickness calibration processes in existing technologies. It also avoids the need to load and unload multiple standard sheets one by one, greatly reducing the cost of standard sheets, improving the calibration efficiency of the equipment, and preventing the standard sheet from breaking during the sheet replacement process.

[0051] The preparation method for the film thickness standard sheet described above is explained below. For details, please refer to... Figure 1As shown, the method for preparing the film thickness standard sheet may include: providing a substrate 100, on which at least one calibration region is defined; then, forming at least one groove 110 in the calibration region of the substrate 100 and obtaining a first opening size SCD1 of the groove 110; and / or, forming at least one protrusion 120 in the calibration region of the substrate 100 and obtaining a first width size LCD1 of the protrusion 120; then, forming a thin film layer 200 on the substrate 100, the thin film layer 200 at least covering the calibration region, wherein... When a groove 110 is formed in the calibration area, the second opening size SCD2 of the groove 110 after covering the thin film layer 200 is obtained; when a protrusion 120 is formed in the calibration area, the second width size LCD2 of the protrusion 120 after covering the thin film layer 200 is obtained; then, the thickness value THK of the thin film layer 200 is obtained based on the difference between the first opening size SCD1 and the second opening size SCD2, and / or the difference between the second width size LCD2 and the first width size LCD1.

[0052] Specifically, when a groove 110 is formed in the calibration area, the first opening size SCD1 and the second opening size SCD2 of the groove 110 before and after the covering film layer 200 are obtained, and the thickness value THK of the film layer 200 is obtained based on the difference between the first opening size SCD1 and the second opening size SCD2, i.e., THK = (SCD1 - SCD2) / 2. The inclination of the sidewall of the formed groove 110 can be between 85° and 95° (i.e., the angle between the sidewall of the groove and the bottom surface of the groove is 85°-95°), so that the sidewall of the groove 110 is a vertical sidewall or a near-vertical sidewall, which facilitates more accurate measurement of the opening size of the groove 110 before and after the covering film layer 200.

[0053] Furthermore, when a protrusion 120 is formed within the calibration area, the first width dimension LCD1 and the second width dimension LCD2 of the protrusion 120 before and after the covering film layer 200 are obtained, and the thickness value THK of the film layer 200 is obtained based on the difference between the second width dimension LCD2 and the first width dimension LCD1, i.e., THK = (LCD2 - LCD1) / 2. The sidewall inclination of the formed protrusion 120 is 85°-95° ​​(i.e., the angle between the sidewall of the protrusion and the top surface of the substrate is between 85°-95°), so that the sidewall of the protrusion 120 is a vertical sidewall or a near-vertical sidewall, which facilitates more accurate measurement of the width dimension of the protrusion 120 before and after the covering film layer 200.

[0054] Furthermore, when both groove 110 and protrusion 120 are formed in the calibration area, the first opening size SCD1 and the second opening size SCD2 of groove 110 before and after covering film layer 200, and the first width size LCD1 and the second width size LCD2 of protrusion 120 before and after covering film layer 200 can be obtained. At this time, the first thickness value THK1 can be obtained according to the first opening size SCD1 and the second opening size SCD2, and the second thickness value THK2 can be obtained according to the first width size LCD1 and the second width size LCD2. Then, the thickness value THK of film layer 200 can be obtained based on the average value of the first thickness value THK1 and the second thickness value THK2, that is, THK = (THK1 + THK2) / 2.

[0055] When both grooves 110 and protrusions 120 are formed simultaneously within the calibration area, the process further includes: determining whether the absolute value of the difference between the obtained first thickness value THK1 and the second thickness value THK2 is less than or equal to a preset threshold spec; if so, it means that the formed thin film layer 200 has high coverage performance, and based on this, the thickness value of the thin film layer 200 is obtained according to the average value of the first thickness value THK1 and the second thickness value THK2; if not, rework can be performed to reformat the thin film layer 200 until the absolute value of the difference between the obtained first thickness value THK1 and the second thickness value THK2 is less than or equal to the preset threshold spec. By comparing the first thickness value THK1 obtained based on the groove 110 and the second thickness value THK2 obtained based on the protrusion 120, the coverage uniformity of the formed thin film layer 200 is further verified, so that the formed standard sheet can achieve high specifications and ensure the quality of the standard sheet.

[0056] In a specific example, at least two grooves 110 may be formed in the calibration area of ​​the substrate 100, and a protrusion 120 may be formed in the portion of the substrate 110 corresponding to the portion between two adjacent grooves 110 (the protrusion formed in the substrate may constitute a first protrusion). In addition, the protrusion 120 in the calibration area may also be a second protrusion protruding from the top surface of the substrate.

[0057] To more clearly explain the preparation method of the film thickness standard sheet provided in this embodiment, the following is in conjunction with... Figure 3 and Figures 4-5 An example is provided to illustrate the preparation of... Figure 1 The standard sample shown is used as an example for explanation. Figure 3 This is a schematic flowchart of a method for preparing a film thickness standard sheet according to an embodiment of the present invention. Figures 4-5 This is a schematic diagram of the structure of the film thickness standard sheet in the preparation process of one embodiment of the present invention. It can be considered that... Figure 4 and Figure 5 The structure of only one calibration area is shown schematically.

[0058] First refer to Figure 3 and Figure 4 As shown, a substrate 100 is provided, on which at least one calibration region is defined. In a specific example, at least two calibration regions may be defined on the substrate 100, wherein at least a portion of the calibration regions are used to fabricate thin film layers of different thicknesses. The substrate 100 is, for example, a wafer.

[0059] Continue to refer to Figure 3 and Figure 4 As shown, at least two grooves 110 are formed in the calibration area of ​​the substrate 100, and a protrusion 120 is formed in the substrate 100 corresponding to the portion between adjacent grooves 110, which can constitute a first protrusion. Furthermore, the first opening size SCD1 of the groove 110 and the first width size LCD1 of the protrusion 120 are obtained, wherein the first opening size of the groove 110 and the second opening size of the protrusion 120 can be measured using a scanning electron microscope to improve measurement accuracy.

[0060] Next, refer to Figure 3 and Figure 5 As shown, a thin film layer 200 is formed on the substrate 100. The thin film layer 200 at least covers the top surface of the substrate in the calibration region and conformally covers the groove 110 and the protrusion 120. The thin film layer 200 can be formed using a thin film deposition process.

[0061] Continue to refer to Figure 3 and Figure 5 As shown, the second opening size SCD2 of the groove 110 after the covering film layer 200 is obtained, and the second width size LCD2 of the protrusion 120 after the covering film layer 200 is obtained. Similarly, the second opening size SCD2 and the second width size LCD2 can be measured using a scanning electron microscope to improve measurement accuracy.

[0062] Next, the first thickness value THK1 can be obtained based on the first opening size SCD1 and the second opening size SCD2, and the second thickness value THK2 can be obtained based on the first width size LCD1 and the second width size LCD2.

[0063] Continue to refer to Figure 3As shown, it is determined whether the absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is less than or equal to a preset threshold spec. Specifically, when the absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is less than or equal to the preset threshold spec (|THK1-THK2|≤spec), it means that the coverage performance of the thin film layer 200 covering the groove 110 and the protrusion 120 is similar, thus possessing higher coverage uniformity and more accurately reflecting the thickness of the thin film layer 200 covering the top surface of the substrate, improving the quality of the prepared standard sheet. Conversely, when the absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is greater than the preset threshold spec (|THK1-THK2|>spec), it means that the coverage performance of the thin film layer 200 for the groove 110 and the protrusion 120 differs significantly, and its coverage uniformity is poor. In this case, rework can be performed to reformat the thin film layer 200 until the thickness difference of the reformed thin film layer 200 covering the groove 110 and the protrusion 120 is less than or equal to the preset threshold spec.

[0064] That is, in this example, the first thickness value THK1 corresponding to the groove 110 and the second thickness value THK2 corresponding to the protrusion 120 are used for mutual verification to further improve the thickness uniformity of the formed thin film layer 200, so that the thin film layer 200 with higher specifications can be further used as a film thickness standard sheet, thereby improving the quality of the standard sheet.

[0065] Then, the thickness value THK of the thin film layer 200 can be obtained based on the average of the first thickness value THK1 and the second thickness value THK2, that is, THK = (THK1 + THK2) / 2.

[0066] Furthermore, in one example, the substrate 100 has at least two calibration regions, and at least a portion of the calibration regions are used to prepare thin film layers 200 of different thicknesses. Specifically, for calibration regions of different thicknesses, thin film layers of different thicknesses are formed within the corresponding calibration regions. The following explanation uses an example where a first calibration region and a second calibration region are formed within the substrate 100, and the first and second calibration regions are used to form first and second thin film layers of different thicknesses, respectively.

[0067] Specifically, the method for forming a first thin film layer and a second thin film layer of different thicknesses in the first calibration region and the second calibration region includes: first, forming at least one groove 110 and / or at least one protrusion 120 in each calibration region of the substrate 100; then, forming a first thin film layer in the first calibration region and obtaining the thickness value of the first thin film layer, wherein the thickness value of the first thin film layer can be obtained by the first thickness value THK1 and / or the second thickness value THK2 as described above; then, forming a second thin film layer in the second calibration region and obtaining the thickness value of the second thin film layer, wherein the thickness value of the second thin film layer can also be obtained by the first thickness value THK1 and / or the second thickness value THK2 as described above.

[0068] It should be recognized that when the substrate 100 also has calibration areas for forming other thicknesses, the deposition process of the thin film layer can be repeated, and this cyclic step of obtaining the thickness of the thin film layer in the corresponding area can be continued.

[0069] This embodiment also provides a calibration method for a film thickness measuring device, which specifically includes the following steps.

[0070] The first step involves providing a film thickness standard sheet as described above. This standard sheet has at least one calibration region on which a thin film layer is formed. The thin film layer covers the top surface of the substrate, grooves, and / or protrusions within the calibration region. As described above, the thickness of the thin film layer within the calibration region of the standard sheet is specifically obtained based on the dimensional changes before and after the thin film layer covers the grooves and / or protrusions. The obtained thin film layer thickness constitutes a standard value for the thickness of the thin film layer within the calibration region, which is used as a thickness reference in subsequent calibration processes.

[0071] The second step involves using a film thickness measurement device to measure the thickness of the thin film layer on the film thickness standard sheet, thereby obtaining the thickness measurement value of the thin film layer on the standard sheet. Specifically, the film thickness measurement device can measure the thickness of the portion of the thin film layer covering the top surface of the substrate. For example, the thickness measurement value of the thin film layer can be obtained based on the optical path difference between the reflected light from the top surface of the film layer and the reflected light from the top surface of the substrate.

[0072] The third step involves comparing the measured thickness of the thin film layer with the standard thickness value to determine if the film thickness measuring device is malfunctioning. Specifically, if the measured thickness value differs significantly from the standard thickness value, it indicates poor measurement accuracy of the film thickness measuring device, requiring calibration. Conversely, if the difference between the measured thickness value and the standard thickness value is within the allowable error range, it indicates that the film thickness measuring device has normal measurement accuracy and high precision.

[0073] In a further embodiment, the provided film thickness standard sheet may have at least two calibration areas. During the calibration of the film thickness measuring device, the thickness of the film layer within one calibration area can be measured first. Then, the measurement point is moved to the other calibration area, and the thickness is measured again. This allows for calibration processes at different thickness levels. In other words, this embodiment can utilize the same standard sheet to achieve calibration processes for multiple different thicknesses without the need to replace the standard sheet, eliminating the sheet replacement process, greatly improving calibration efficiency, saving calibration time, and effectively reducing the risk of standard sheet damage caused by frequent replacements.

[0074] Based on the core concept provided by this invention, this embodiment also provides a method for obtaining film thickness, specifically including the following steps. This embodiment utilizes... Figures 4-5 The structure shown illustrates the method for obtaining the film thickness.

[0075] Step 1: Form at least one groove 110 on the substrate 100 and obtain the first opening size SCD1 of the groove 110; and / or, form at least one protrusion 120 on the substrate 100 and obtain the first width size LCD1 of the protrusion 120.

[0076] As described above, when a groove 110 is formed on the substrate 100, the inclination of the sidewall of the groove 110 can be between 85° and 95° (i.e., the angle between the sidewall of the groove and the bottom surface of the groove is 85°-95°), so that the sidewall of the groove 110 is a vertical sidewall or a near-vertical sidewall. Similarly, when a protrusion 120 is formed in the calibration area of ​​the substrate 100, the inclination of the sidewall of the protrusion 120 can be between 85° and 95° (i.e., the angle between the sidewall of the protrusion and the top surface of the substrate is between 85° and 95°), so that the sidewall of the protrusion 120 is a vertical sidewall or a near-vertical sidewall. This facilitates more accurate measurement of the opening size of the groove 110 before and after the cover film layer 200, and the width size of the protrusion 120 before and after the cover film layer 200.

[0077] The first opening size SCD1 of the groove 110 and the first width size LCD1 of the protrusion 120 can both be obtained using a scanning electron microscope (SEM). More specifically, a critical dimension scanning electron microscope (CD-SEM) can be used to measure the above dimensions more accurately.

[0078] Step 2: Form a thin film layer 200 on the substrate 100. Specifically, the thin film layer 200 can be deposited on the substrate 100 using a thin film deposition device.

[0079] Specifically, when a groove 110 is formed on the substrate 110, a thin film layer 200 covers the groove 110, and the second opening size SCD2 of the groove 110 in the opening region after covering the thin film layer 200 is obtained; and when a protrusion 120 is formed on the substrate 100, the second width size LCD2 of the protrusion 120 after covering the thin film layer 200 is obtained. Similarly, this step can also be obtained using a scanning electron microscope (SEM), more specifically, a critical dimension scanning electron microscope (CD-SEM) can be used to more accurately measure the second opening size SCD2 and the second width size LCD2.

[0080] Step 3: Obtain the thickness value THK of the thin film layer 200 based on the difference between the first opening size SCD1 and the second opening size SCD2, and / or the difference between the second width size LCD2 and the first width size LCD1.

[0081] Specifically, when only grooves 110 are formed on the substrate 100, the thickness value THK of the thin film layer 200 can be obtained based on the difference between the first opening size SCD1 and the second opening size SCD2, i.e., THK = (SCD1 - SCD2) / 2. When only protrusions 120 are formed on the substrate 100, the thickness value THK of the thin film layer 200 can be obtained based on the difference between the second width size LCD2 and the first width size LCD1, i.e., THK = (LCD2 - LCD1) / 2. When grooves 110 and protrusions 120 are formed on the substrate at the same time, the first thickness value THK1 can be obtained based on the first opening size SCD1 and the second opening size SCD2, THK1 = (SCD1 - SCD2) / 2, and the second thickness value THK2 can be obtained based on the first width size LCD1 and the second width size LCD2, THK2 = (LCD2 - LCD1) / 2. The thickness of the thin film layer 200 is obtained by the average of the first thickness value THK1 and the second thickness value THK2, that is, THK = (THK1 + THK2) / 2.

[0082] In this embodiment, taking the simultaneous formation of grooves 110 and protrusions 120 on the substrate 100 as an example, the actual thickness of the deposited thin film layer 200 can be obtained more accurately based on the film layer thickness on the grooves 110 and protrusions 120. Specifically, at least two grooves 110 are formed in the substrate 100, and protrusions 120 are formed from the portions of the substrate 100 corresponding to the spaces between adjacent grooves. In other examples, the protrusions may, for example, protrude from the top surface of the substrate.

[0083] Furthermore, by simultaneously forming grooves 110 and protrusions 120 on the substrate 100, the obtained first thickness value THK1 and second thickness value THK2 can be mutually verified to determine the uniformity of the film thickness of the deposited thin film layer 200, and can further reflect the performance of the thin film deposition equipment currently used.

[0084] Specifically, after obtaining the first thickness value THK1 and the second thickness value THK2, it is determined whether the absolute value of the difference between the first thickness value THK1 and the second thickness value THK2 is less than or equal to a preset threshold spec. If so (i.e., |THK1-THK2|≤spec), it means that the thin film layer 200 has higher thickness uniformity, and the thin film deposition equipment used can achieve higher process accuracy. At this time, the thickness value of the thin film layer 200 can be obtained according to the average value of the first thickness value THK1 and the second thickness value THK2, i.e., THK = (THK1+THK2) / 2. If not, it means that the coverage uniformity of the thin film layer 200 is poor, reflecting that the thin film deposition equipment used may have an accuracy abnormality. At this time, rework processing can be performed on the current thin film layer 200, and the thin film layer 200 can be re-formed until the formed thin film layer 200 satisfies |THK1-THK2|≤spec. At the same time, the thin film deposition equipment can be stopped for inspection to avoid the formation of a large number of thin film layers that do not meet the thickness uniformity requirement.

[0085] Therefore, in the process of obtaining the film thickness provided in this embodiment, on the one hand, the thickness of the formed film layer can be accurately obtained; on the other hand, it is also beneficial to monitor the thickness uniformity of the formed film layer, and on this basis, it is possible to further monitor the abnormality of the film deposition equipment.

[0086] It should be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

[0087] It is important to note that the singular forms “a” and “an” used herein and in the appended claims include the plural basis unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” implies a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Furthermore, the word “or” should be understood with the definition of logical “or”, not logical “exclusive OR”, unless the context clearly indicates otherwise.

Claims

1. A film thickness standard sheet, characterized by, The method comprises: a substrate and a thin film layer formed on the substrate, the substrate having at least one calibration area, and the thin film layer covering at least the calibration area; wherein, at least one groove and at least one protrusion are formed in the calibration area of the substrate, the groove has a first opening size, and the thin film layer covers the groove and the top surface of the substrate, the thin film layer covering the groove reduces the opening area of the groove to a second opening size, and a first thickness value of the thin film layer is obtained according to the difference between the first opening size and the second opening size; the protrusion has a first width size, and the thin film layer covers the protrusion and the top surface of the substrate, the thin film layer covering the protrusion forms a second width size, and a second thickness value of the thin film layer is obtained according to the difference between the second width size and the first width size, and the thickness value of the thin film layer is obtained based on the average of the first thickness value and the second thickness value; and the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold value.

2. The film thickness standard according to claim 1, wherein The calibration area of the substrate has at least two grooves, and the substrate has a first protrusion corresponding to the part between the adjacent two grooves.

3. The film thickness standard according to claim 1, wherein The at least one protrusion includes a second protrusion protruding from the top surface of the substrate.

4. The film thickness standard according to claim 1, wherein The side wall of the groove has an inclination of 85°-95°; and / or, the side wall of the protrusion has an inclination of 85°-95°.

5. The film thickness standard according to claim 1, wherein The substrate has at least two calibration areas, and the thickness of the thin film layer formed in at least part of the calibration areas is different.

6. The film thickness standard according to claim 1, wherein The substrate has at least two calibration areas, and part of the calibration areas are arranged in the central area of the substrate, and the other part of the calibration areas are arranged in the edge area of the substrate.

7. A method for producing a film thickness standard sheet, characterized by, The method comprises: providing a substrate, and defining at least one calibration area on the substrate; forming at least one groove and at least one protrusion in the calibration area of the substrate, and obtaining a first opening size of the groove and a first width size of the protrusion; forming a thin film layer on the substrate, and the thin film layer covering at least the calibration area; obtaining a second opening size of the opening area of the groove after covering the thin film layer and a second width size of the protrusion after covering the thin film layer; and, obtaining a first thickness value according to the difference between the first opening size and the second opening size, and obtaining a second thickness value according to the difference between the second width size and the first width size; determining whether the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold value; if yes, the formed thin film layer meets the requirements of a standard piece, and the thickness value of the thin film layer is obtained according to the average of the first thickness value and the second thickness value; if no, rework is performed to reform the thin film layer until the absolute value of the difference between the obtained first thickness value and the second thickness value is less than or equal to the preset threshold value.

8. The method of producing a film thickness standard according to claim 7, wherein The substrate has at least two grooves, and the substrate has a first protrusion corresponding to the part between the adjacent two grooves.

9. The method of producing a film thickness standard according to claim 7, wherein The at least one protrusion comprises a second protrusion protruding from the top surface of the substrate.

10. The method of producing a film thickness standard according to claim 7, wherein The substrate has at least two calibration regions, and the thickness of the thin film layer formed in at least part of the calibration regions is different.

11. The method of producing a film thickness standard according to claim 10, wherein The method for forming the at least two calibration regions comprises: forming at least one groove and / or at least one protrusion in each calibration region of the substrate; forming a first thin film layer in the first calibration region and obtaining the thickness value of the first thin film layer; and forming a second thin film layer in the second calibration region and obtaining the thickness value of the second thin film layer.

12. The method of producing a film thickness standard according to claim 7, wherein The side wall of the groove has an inclination of 85°-95°; and / or the side wall of the protrusion has an inclination of 85°-95°.

13. A method of calibrating a film thickness measuring apparatus, characterized by, The method comprises: providing the film thickness standard piece according to any one of claims 1-6; measuring the thickness of the thin film layer on the film thickness standard piece by using a film thickness measuring device to obtain the thickness measurement value of the thin film layer on the standard piece; and comparing the thickness measurement value of the thin film layer with the thickness standard value of the thin film layer to determine whether the film thickness measuring device is abnormal.

14. The method of calibrating a film thickness measuring apparatus according to claim 13, wherein The film thickness standard piece has at least two calibration regions; The film thickness measuring device preferentially measures the thickness of the thin film layer in one of the calibration regions, and then moves the measurement point to the other calibration region to measure the thickness, so as to realize the calibration of different thicknesses.

15. A method of acquiring a film layer thickness, characterized by, The method comprises: forming at least one groove and at least one protrusion on the substrate, and obtaining the first opening size of the groove and the first width size of the protrusion; forming a thin film layer on the substrate, the thin film layer covering the groove and the protrusion, and obtaining the second opening size of the opening area of the groove after covering the thin film layer and the second width size of the protrusion after covering the thin film layer; and and obtaining a first thickness value according to the difference between the first opening size and the second opening size, and obtaining a second thickness value according to the difference between the second width size and the first width size; determining whether the absolute value of the difference between the first thickness value and the second thickness value is less than or equal to a preset threshold value; if yes, obtaining the thickness value of the thin film layer according to the average value of the first thickness value and the second thickness value.

16. The method of claim 15, wherein The substrate has at least two grooves, and a first protrusion of the at least one protrusion is formed in the substrate corresponding to the part between adjacent grooves.

17. The method of claim 15, wherein The side wall of the groove has an inclination of 85°-95°; and / or the side wall of the protrusion has an inclination of 85°-95°.

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