A semiconductor measurement structure and a semiconductor polishing amount measurement method

Abstract

The present application relates to the field of semiconductor technology, and discloses a semiconductor measurement structure and a method for measuring semiconductor grinding amount. The semiconductor measurement structure is arranged on a wafer, and the semiconductor measurement structure includes at least a groove area and a grinding area; wherein the top surface of the grinding area is higher than the top surface of the groove area, and the sidewall of the grinding area and the top surface of the groove area are enclosed to form a measurement groove; the grinding amount of the grinding area is determined by measuring the step difference between the grinding area and the top surface of the groove area before and after the chemical mechanical polishing process. The present application can avoid the generation of optical interference, thereby avoiding affecting the measured value of the grinding amount of the chemical mechanical polishing process, reducing the measurement deviation between the actual value and the measured value, and thus improving the measurement accuracy.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, for example, to a semiconductor measurement structure and a method for measuring semiconductor polishing amount. Background Art

[0002] In recent years, MRAM (Magnetic Random Access Memory) has become a promising new type of memory due to its high speed, low power consumption, and non-volatility. Chemical Mechanical Polishing (CMP) is often used in MRAM manufacturing. Evaluating whether this process meets process standards (for example, evaluating the polishing volume during CMP) is a key technology in CMP.

[0003] Related art discloses a method for measuring the chemical mechanical polishing process. This method uses an optical measurement instrument (such as an ellipsometer) commonly used in wafer fabrication plants to measure the film thickness of a test key. This thickness is used to represent the actual thickness of the corresponding film layer in the corresponding area. The polishing amount of the chemical mechanical polishing process is then evaluated based on the real-time monitored thickness value.

[0004] During the implementation of the embodiments of the present disclosure, it was found that at least the following problems exist in the related art:

[0005] Optical measurement is easily affected by factors such as the undulation and unevenness of the underlying film layer and the thickness of the film deposition, which can easily affect the measured value of the grinding amount in the chemical mechanical polishing process, causing a measurement deviation between the measured value and the actual value, thereby affecting the measurement accuracy. Summary of the Invention

[0006] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0007] The embodiments of the present disclosure provide a semiconductor measurement structure and a semiconductor polishing amount measurement method to avoid optical interference, thereby avoiding affecting the measurement value of the polishing amount in the chemical mechanical polishing process, reducing the measurement deviation between the actual value and the measured value, and thus improving the measurement accuracy.

[0008] In some embodiments, the semiconductor measurement structure is disposed on a wafer, and the semiconductor measurement structure includes at least a groove area and a grinding area; wherein the top surface of the grinding area is higher than the top surface of the groove area, and the sidewalls of the grinding area and the top surface of the groove area together form a measurement groove; the grinding amount of the grinding area is determined by measuring the step difference between the grinding area and the top surface of the groove area before and after the chemical mechanical polishing process.

[0009] Optionally, the step difference measuring instrument includes at least: a step profiler or an atomic force microscope.

[0010] Optionally, the grinding area is configured as a film layer structure, and the types of the film layers in the grinding area include a single type or multiple types.

[0011] Optionally, the number of the semiconductor measurement structures is set to one or more.

[0012] Optionally, the size of the measuring groove is determined by the size of the abrasive particles in the polishing liquid, so that the line width of the measuring groove is smaller than the diameter of the abrasive particles.

[0013] Optionally, the depth of the measuring groove is determined by the size of the abrasive in the polishing liquid and the line width of the measuring groove, so that the height difference between the lowest point where the abrasive penetrates the measuring groove and the top surface of the polishing area before and after the chemical mechanical polishing process is less than the depth of the measuring groove.

[0014] The semiconductor measurement structure provided by the embodiments of the present disclosure can achieve the following technical effects:

[0015] A semiconductor measurement structure is formed on the wafer. This semiconductor measurement structure is composed of a measurement trench formed by a groove region and a polishing region. Because the top surface of the polishing region is higher than the top surface of the groove region, the polishing region and the groove region form a stepped shape through the measurement trench. This step value can be measured using a step profiler or an atomic force microscope (AFM). Before the chemical mechanical polishing process, the step value between the polishing region and the top surface of the groove region is measured as the pre-step value. After the chemical mechanical polishing process, the step value between the polishing region and the top surface of the groove region is measured as the post-step value. The difference between the pre-step value and the post-step value can be used to determine the polishing amount of the polishing region, which can be used as the measurement value of the polishing amount during the chemical mechanical polishing process. When the wafer's bottom surface is uneven (e.g., micro-undulations), conventional optical measurement can generate optical interference (such as diffuse reflection) due to the wafer's bottom surface unevenness, leading to measurement deviations and affecting measurement accuracy. However, the present embodiment uses the step difference measurement method described above, rather than optical measurement. Instead, it simply measures the step difference before and after the chemical mechanical polishing process to obtain the measurement value, which is unaffected by the wafer's bottom surface uniformity, resulting in more accurate measurement results. Furthermore, optical measurement is also limited by the difficulty in measuring metal materials and unknown optical film layer information. However, the measurement method provided by the present embodiment is not limited by the film material of the semiconductor measurement structure. Furthermore, even when there is no optical film layer information for the corresponding film layer, the semiconductor measurement structure of the present application can still be used for measurement. Therefore, the semiconductor measurement structure of the present application has a wider range of applications. Furthermore, compared to the equipment cost of optical measurement equipment, the equipment cost of step difference measurement equipment (such as a step profiler, atomic force microscope, etc.) is lower, so the present application can significantly reduce measurement costs.

[0016] In some embodiments, the semiconductor polishing amount measurement method includes at least: forming a semiconductor measurement structure on a wafer; wherein the semiconductor measurement structure includes at least a groove area and a polishing area; the top surface of the polishing area is higher than the top surface of the groove area, and the sidewalls of the polishing area and the top surface of the groove area together form a measurement groove; and determining the polishing amount of the polishing area by measuring the step difference between the polishing area and the top surface of the area before and after the chemical mechanical polishing process.

[0017] Optionally, before one or more chemical mechanical polishing processes in the wafer manufacturing process, one or more corresponding measuring grooves are formed, and each measuring groove is formed by enclosing the side wall of the corresponding grinding area and the top surface of the corresponding groove area; by measuring the step difference corresponding to the measuring groove before and after grinding of the corresponding chemical mechanical polishing process, the grinding amount of the corresponding grinding area is determined.

[0018] Optionally, forming a measurement groove includes at least: a first preceding process before the chemical mechanical polishing process; before the first preceding process, determining that the preset size of the initial groove is a first size, and the first size is the same as the preset size of the measurement groove; adjusting the preset size of the initial groove to a second size by a preset change amount of the preset size of the initial groove through the first preceding process, so that the vector sum of the second size and the preset change amount is equal to the first size; forming the initial groove according to the second size; executing the first preceding process to change the actual size of the initial groove from the second size to the first size, thereby forming the measurement groove.

[0019] Optionally, forming the measurement trench at least includes: performing a second pre-process before the chemical mechanical polishing process; and directly forming the measurement trench in the second pre-process according to a preset size of the measurement trench.

[0020] The semiconductor polishing amount measurement method provided by the embodiments of the present disclosure can achieve the following technical effects:

[0021] A semiconductor measurement structure is formed on a wafer. The measurement trench is formed by a groove region and a polishing region. Because the top surface of the polishing region is higher than the top surface of the groove region, the polishing region and the groove region form a stepped shape through the measurement trench. This allows the step value to be measured using a step profiler or atomic force microscope. Before the chemical mechanical polishing process, the step value between the polishing region and the top surface of the groove region is measured as the pre-step value. After the chemical mechanical polishing process, the step value between the polishing region and the top surface of the groove region is measured as the post-step value. The difference between the pre-step value and the post-step value can be used to determine the polishing amount of the polishing region. This polishing amount can be used as the polishing amount measurement value of the chemical mechanical polishing process. When the wafer's bottom surface is uneven (e.g., micro-undulations), conventional optical measurement can generate optical interference (such as diffuse reflection) due to the wafer's bottom surface unevenness, leading to measurement deviations and affecting measurement accuracy. However, the present embodiment uses the step difference measurement method described above, rather than optical measurement. Instead, it simply measures the step difference before and after the chemical mechanical polishing process to obtain the measurement value, which is unaffected by the wafer's bottom surface uniformity, resulting in more accurate measurement results. Furthermore, optical measurement is also limited by the difficulty in measuring metal materials and unknown optical film layer information. However, the measurement method provided by the present embodiment is not limited by the film material of the semiconductor measurement structure. Furthermore, even when there is no optical film layer information for the corresponding film layer, the semiconductor measurement structure of the present application can still be used for measurement. Therefore, the semiconductor measurement structure of the present application has a wider range of applications. Furthermore, compared to the equipment cost of optical measurement equipment, the equipment cost of step difference measurement equipment (such as a step profiler, atomic force microscope, etc.) is lower, so the present application can significantly reduce measurement costs.

[0022] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation. In addition,

[0024] Figure 1 1 is a cross-sectional view of a semiconductor measurement structure provided by an embodiment of the present disclosure before and after being processed by a chemical mechanical polishing process.

[0025] Figure 2 1 is a cross-sectional view of another semiconductor measurement structure provided by an embodiment of the present disclosure before and after being processed by a chemical mechanical polishing process.

[0026] Figure 3 1 is a cross-sectional view of a semiconductor measurement structure including only a single film layer provided by an embodiment of the present disclosure.

[0027] Figure 4 1 is a cross-sectional view of a semiconductor measurement structure including multiple types of film layers provided by an embodiment of the present disclosure.

[0028] Figure 5 This is a cross-sectional view of the spacing between film layers of the same type in a semiconductor measurement structure provided by an embodiment of the present disclosure.

[0029] Figure 6 This is a cross-sectional view of the continuous arrangement of film layers of the same type in a semiconductor measurement structure provided by an embodiment of the present disclosure.

[0030] Figure 7 1 is a top view of a semiconductor measurement structure including an annular measurement trench provided by an embodiment of the present disclosure.

[0031] Figure 8 1 is a top view of a semiconductor measurement structure including strip-shaped and cross-shaped measurement trenches provided by an embodiment of the present disclosure.

[0032] Figure 9 Schematic diagram of abrasive grain size and measured groove line width in a chemical mechanical polishing process provided by an embodiment of the present disclosure.

[0033] Figure 10 Schematic diagram of abrasive grain size and measured groove depth in a chemical mechanical polishing process provided by an embodiment of the present disclosure.

[0034] Figure 11 Schematic diagram of a semiconductor polishing amount measurement method provided by an embodiment of the present disclosure.

[0035] Figure 12 Schematic diagram of a measurement trench formation process provided by an embodiment of the present disclosure.

[0036] Reference numerals:

[0037] 1: Grinding area; 2: Groove area; 3: Measurement groove; 4: Abrasive particles. DETAILED DESCRIPTION

[0038] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0039] In the description of the embodiments of the present disclosure and the accompanying drawings, the terms "first," "second," and the like are used to distinguish similar items and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to describe the embodiments of the present disclosure herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0040] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0041] Unless otherwise stated, the term "plurality" means two or more.

[0042] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0043] In recent years, MRAM, due to its high speed, low power consumption, and non-volatility, has become a trendsetting new memory technology. Chemical mechanical polishing (CMP) is often used in MRAM manufacturing. However, assessing whether this process meets process standards (for example, evaluating the polishing volume during CMP) is a key technology in CMP.

[0044] Related art discloses a method for measuring the chemical mechanical polishing process. This method uses an optical measurement machine (such as an ellipsometer) commonly used in wafer manufacturing plants to measure the film thickness of a test unit. This is used to represent the actual thickness of the corresponding film layer in the corresponding area. The grinding amount of the chemical mechanical polishing process is then evaluated based on the real-time monitored thickness value.

[0045] During the implementation of the embodiments of the present disclosure, it was found that at least the following problems exist in the related art:

[0046] Optical measurement methods are easily affected by factors such as the undulation and unevenness of the underlying film layer and the thickness of the film deposition, which can easily affect the measured value of the grinding amount in the chemical mechanical polishing process, resulting in measurement deviation, thereby affecting the measurement accuracy.

[0047] The factors that affect the measured value of the grinding amount by the optical measurement method include but are not limited to the following situations: First, the underlying film layer of the wafer being measured is undulating, and there is an unevenness problem on the surface of the film layer, which causes interference such as diffuse reflection during optical measurement, thereby affecting the measured value of the grinding amount. Second, the thickness of the film deposition of the wafer being measured affects light transmittance, thereby affecting the measured value of the grinding amount. Third, the film material of the wafer being measured includes metal materials that are difficult to transmit light, thereby affecting the measured value of the grinding amount. Fourth, there are multiple types of film layers on the wafer being measured, and the adjacent interfaces between different types of film layers will aggravate the degree of complex reflection, refraction, scattering and other phenomena, thereby affecting the measured value of the grinding amount. The influencing factors listed in the embodiments of the present disclosure are only exemplary statements. The influencing factors in the actual measurement process include but are not limited to the influencing factors listed in the embodiments of the present disclosure, and will not be repeated here.

[0048] It should be noted that the semiconductor measurement structure and semiconductor polishing amount measurement method used in the embodiments of the present disclosure are not limited to the MRAM manufacturing process but are also applicable to the manufacturing processes of other non-MRAM devices, such as the manufacturing processes of CMOS (Complementary Metal-Oxide-Semiconductor) devices.

[0049] Combine Figure 1 and Figure 2As shown, an embodiment of the present disclosure provides a semiconductor measurement structure, which is arranged on a wafer. The semiconductor measurement structure includes at least a groove area 2 and a grinding area 1; wherein the top surface of the grinding area 1 is higher than the top surface of the groove area 2, and the sidewall of the grinding area 1 and the top surface of the groove area 2 are combined to form a measurement groove 3; the grinding amount of the grinding area 1 is determined by measuring the step difference between the top surfaces of the grinding area 1 and the groove area 2 before and after the chemical mechanical polishing process.

[0050] It should be noted that the top surface of the groove region 2 is the bottom of the measurement groove 3 , and the sidewall of the polishing region 1 is the sidewall of the measurement groove 3 .

[0051] Using the semiconductor measurement structure provided in the embodiments of the present disclosure, a semiconductor measurement structure is formed on a wafer. The semiconductor measurement structure comprises a measurement groove 3 formed by a groove region 2 and a grinding region 1. Since the top surface of grinding region 1 is higher than the top surface of groove region 2, the grinding region 1 and the groove region 2 are stepped through the measurement groove 3, thereby enabling the step value here to be measured using a step profiler or an atomic force microscope. Before the chemical mechanical polishing process, the step value between the top surfaces of grinding region 1 and groove region 2 is measured as the pre-step value. After the chemical mechanical polishing process, the step value between the top surfaces of grinding region 1 and groove region 2 is measured as the post-step value. The difference between the pre-step value and the post-step value can be used to determine the grinding amount of grinding region 1. This grinding amount can be used as the measurement value of the grinding amount in the chemical mechanical polishing process. When the wafer's underlying surface is non-uniform (e.g., micro-undulations), conventional optical measurement can generate optical interference (e.g., diffuse reflection) due to the wafer's underlying surface non-uniformity, leading to measurement deviations and impacting measurement accuracy. However, the present embodiment utilizes the aforementioned step difference measurement method, rather than optical measurement. This method simply measures the step difference before and after the chemical mechanical polishing process to obtain a measurement value, which is unaffected by the wafer's underlying surface uniformity, resulting in more accurate measurement results. Furthermore, optical measurement is limited by the difficulty of measuring metal materials and unknown optical film information. However, the measurement method provided by the present embodiment is not restricted by the film material of the semiconductor measurement structure. Furthermore, even when there is no optical film information for the corresponding film, the semiconductor measurement structure of the present embodiment can still be used for measurement. Therefore, the semiconductor measurement structure of the present embodiment has a wider range of applications. Furthermore, compared to the equipment cost of optical measurement tools, the equipment cost of step difference measurement equipment (e.g., step profilers, atomic force microscopes, etc.) is lower, thus significantly reducing measurement costs.

[0052] It should be noted that at least one semiconductor measurement structure and at least one core functional area are formed on the wafer based on the same manufacturing process. The core functional area is the area of ​​the actual chip production and manufacturing process and the final constructed area, such as the integrated circuit area, the cutting road area, etc. In the actual preparation process of semiconductor devices, due to different manufacturing requirements, the positional relationship between the semiconductor measurement structure and the core functional area includes but is not limited to the semiconductor measurement structure being arranged around the core functional area, the semiconductor measurement structure being interspersed in the core functional area, etc. When the wafer is ground by a chemical mechanical polishing process, the grinding amount of the above-mentioned grinding area 1 can represent the grinding amount of the grinding area 1 of the semiconductor measurement structure. When the top surface height of part or all of the core functional area is the same as the top surface height of the semiconductor measurement structure, the grinding amount of the above-mentioned grinding area 1 can also represent the grinding amount of this part or all of the core functional area, that is, it can represent the grinding amount of the chemical mechanical polishing process.

[0053] Specific, combined Figure 1 and Figure 2 , measuring the step difference between the top surfaces of the polishing region 1 and the groove region 2 before and after the chemical mechanical polishing process, which is the difference between the pre-step value h1 between the top surfaces of the polishing region 1 and the groove region 2 before the chemical mechanical polishing process and the post-step value h2 between the top surfaces of the polishing region 1 and the groove region 2 after the chemical mechanical polishing process.

[0054] Specifically, the chemical mechanical polishing process at least includes: interlayer dielectric chemical mechanical polishing (ILD CMP).

[0055] Optionally, the step difference measuring instrument includes at least: a step meter or an atomic force microscope. It should be noted that the step meter in the embodiment of the present disclosure includes a mechanical probe step meter. In this way, the working principle of the step meter is to directly contact the surface of the film layer to be measured through the probe. When the probe moves on the surface of the film layer to be measured, due to the presence of steps or height changes on the surface of the film layer to be measured, the probe will move up and down accordingly, and the step value of the surface of the film layer to be measured is obtained by measuring the vertical displacement of the probe. The working principle of the atomic force microscope is based on the force between atoms. The probe is scanned on the surface of the film layer to be measured. When the distance between the probe and the atoms on the surface of the film layer to be measured changes, the atomic force will change accordingly. The step value of the surface of the film layer to be measured is obtained by detecting the change in atomic force. In this way, the measurement value of the step meter depends only on the vertical displacement of the probe, and the measurement value of the atomic force microscope depends only on the change in atomic force. Both do not involve optical measurement methods. Therefore, the measurement method provided by the embodiment of the present disclosure is not limited by the uniformity of the underlying film layer and the material of the film layer being measured. For example, when there is an opaque metal film layer in the polishing area 1, the polishing amount of the polishing area 1 can still be accurately measured, so it has a wider range of applications.

[0056] Optionally, the polishing area 1 involved in the embodiment of the present disclosure is set as a film structure. Considering that during the manufacturing process, due to different manufacturing requirements, the types of film layers formed on the wafer may also be different, therefore, the types of film layers in the polishing area 1 may include a single type or multiple types. Figure 3-Figure 6 Schematic diagram of film types shown, in which some Figure 3 In the embodiment shown, the film type of the grinding area 1 includes a single type, such as a first type of film layer (such as a first dielectric layer). Figure 4 In the embodiment shown, the types of film layers in the grinding area 1 include multiple types, such as a substrate layer, a first dielectric layer, a magnetic tunnel junction film layer, a second dielectric layer, and a third dielectric layer stacked sequentially from bottom to top. Figure 5 and Figure 6 In the illustrated embodiment, the film layers in the polishing region 1 include multiple types, such as a substrate layer, a first type of film layer, a second type of film layer, and a third type of film layer stacked sequentially from bottom to top. Considering that in the actual manufacturing process of semiconductor devices, different film layers may be deposited on a wafer based on different process requirements, it can be seen from the above embodiments that the measurement method provided in the embodiments of the present disclosure is applicable to different film layers formed by different preparation processes. It is not limited by the type of film layer and can achieve polishing measurement of both a single type of film layer and multiple types of film layers, thus having a wider range of applications.

[0057] Specifically, in the actual manufacturing process of semiconductor devices, based on different process requirements, the types of film layers may include multiple types. Due to the differences in optical properties (such as refractive index, extinction coefficient, etc.) between different types of film layers, when performing traditional optical measurements, complex reflection, refraction, and scattering phenomena occur at the interfaces of different film layers, resulting in inaccurate measurement results. In addition, stacking multiple types of film layers will cause the film layers to become thicker, exacerbating the non-uniformity of the optical properties of the film layers (such as the change in refractive index with depth, etc.), which will also cause inaccurate measurement results. However, since the embodiments of the present disclosure do not involve optical measurements, the instrument used to measure the step value in the embodiments of the present disclosure is a step meter or an atomic force microscope. The measurement value depends only on the vertical displacement of the probe or the change in atomic force. The measurement method provided by the embodiments of the present disclosure can be applied to film layers of multiple types and thicknesses formed due to the preparation process. It is not limited by the number of film layer types and the thickness of the film layers. Therefore, the scope of application of the embodiments of the present disclosure is wider.

[0058] Specifically, in the actual manufacturing process of semiconductor devices, based on different process requirements, among the film layer types in the grinding area 1, at least one film layer can be set to be a metal film layer, a metal oxide film layer or a metal nitride film layer, and the film layer thickness is greater than or equal to 50nm.

[0059] Thus, due to the high electron density and strong absorption and scattering properties of metals, when light is transmitted through metal films using traditional optical measurement, it will strongly interact with the electrons in the metal, resulting in a large amount of light being absorbed and scattered, causing its transmittance to be considered as being opaque, and the transmission intensity will not be detected by traditional optical measurement instruments. However, since the instrument used to measure the step value in the embodiment of the present disclosure is a step profiler or an atomic force microscope, the measurement value depends only on the vertical displacement of the probe or the change in atomic force. The measurement method provided by the embodiment of the present disclosure is applicable to a variety of film materials and film layers of various thicknesses formed by the preparation process, and is not limited by the film material and thickness. Therefore, the scope of application of the embodiment of the present disclosure is wider.

[0060] Optionally, the groove area 2 involved in the embodiment of the present disclosure is set as a film layer structure. Considering that the types of film layers formed on the wafer may be different due to different manufacturing requirements during the manufacturing process, the types of film layers in the groove area 2 may include a single type or multiple types. Among them, the type of film layer in the groove area 2 is exactly the same as the type of film layer in the grinding area 1, or partially the same, or completely different. It only needs to ensure that the top surface of the grinding area 1 is higher than the top surface of the groove area 2, and the grinding area 1 and the groove area 2 can be enclosed to form a measuring groove 3. For example Figure 3-Figure 6 The schematic diagram of the film types shown in some examples Figure 3 In the embodiment shown, the film types of the trench region 2 are all of a single type, such as a first type of film layer (eg, a first dielectric layer). Figure 4In the embodiment shown, the film layers of the trench region 2 include multiple types, such as a substrate layer, a first dielectric layer, and a third dielectric layer stacked sequentially from bottom to top. Figure 5 and Figure 6 In the illustrated embodiment, the film layers in the trench region 2 include multiple types, such as a substrate layer, a first type of film layer, and a third type of film layer stacked sequentially from bottom to top. Considering that different film layers may be deposited on a wafer based on different process requirements during the actual manufacturing process of semiconductor devices, the measurement method provided in the above embodiment is applicable to different film layers formed by different preparation processes. It is not limited by the type of film layer and can achieve polishing measurement of both a single type of film layer and multiple types of film layers, thus having a wider range of applications.

[0061] In some Figure 3 In the embodiment shown, when the measurement groove 3 is formed in the case of a single type of film layer, the type of the film layer in the groove area 2 is exactly the same as the type of the film layer in the grinding area 1. Photolithography and etching are used to make the film thickness of the groove area 2 smaller than the film thickness of the grinding area 1, thereby forming the measurement groove 3. At this time, the top surface height of the grinding area 1 is higher than the top surface height of the groove area 2, which is used for subsequent measurement of the grinding amount.

[0062] In other Figure 4 In the illustrated embodiment, when forming the measurement trench 3 using multiple film layers, the initial film layers in the trench region 2 and the polishing region 1 are of the same type: a substrate layer, a first dielectric layer, and a magnetic tunnel junction film layer. The magnetic tunnel junction film layer in the trench region 2 is removed through photolithography and etching, reducing the film thickness in the trench region 2 to a thickness less than that in the polishing region 1, thereby forming the initial trench. At this point, the top surface height of the polishing region 1 is higher than that of the trench region 2. Subsequently, a third dielectric layer is deposited over the initial trench. At this point, the film thickness in the trench region 2 is still less than that in the polishing region 1. The initial trench is then transformed into the measurement trench 3. At this point, the top surface height of the polishing region 1 is higher than that of the trench region 2, allowing for subsequent polishing measurement.

[0063] In other Figure 5In the illustrated embodiment, when forming the measurement trench 3 using multiple types of film layers, a substrate layer is first deposited on the wafer, followed by continuous deposition of multiple layers of the first type of film layer. Multiple layers of the second type of film layer are then continuously deposited to serve as the initial film layers for the trench region 2 and the polishing region 1. The second type of film layer in the trench region 2 is partially removed through photolithography and etching to form the initial trench. At this point, the film layer type in the trench region 2 is partially identical to that in the polishing region 1, the film layer thickness in the trench region 2 is less than that in the polishing region 1, and the top surface height of the polishing region 1 is higher than that of the trench region 2. Multiple layers of the third type of film layer are then deposited on the initial trench. After deposition, the film layer thickness in the trench region 2 is still less than that in the polishing region 1, forming the measurement trench 3. At this point, the top surface height of the polishing region 1 is higher than that of the trench region 2, allowing for subsequent polishing measurement.

[0064] In other Figure 6 In the embodiment shown, when the measuring groove 3 is formed in the case of multiple types of film layers, a substrate layer is first deposited on the wafer, and then the first type of film layer and the second type of film layer are deposited at intervals, so that the wafer is stacked from bottom to top with a substrate layer, a first type of film layer, a second type of film layer, a first type of film layer, and a second type of film layer as the initial film layers of the groove area 2 and the grinding area 1. The two layers of the second type of film layers in the groove area 2 and the first type of film layer arranged between the measuring second type of film layers are removed by photolithography and etching to form an initial groove. At this time, the type of film layer in the groove area 2 is partially the same as the type of film layer in the grinding area 1, the film layer thickness in the groove area 2 is less than the film layer thickness in the grinding area 1, and the top surface height of the grinding area 1 is higher than the top surface height of the groove area 2. Then, a third type of film layer is deposited on the initial groove. After deposition, the film thickness of the groove area 2 is still smaller than the film thickness of the grinding area 1. The initial groove is formed into a measuring groove 3. At this time, the top surface height of the grinding area 1 is higher than the top surface height of the groove area 2, which is used for subsequent grinding amount measurement.

[0065] Optional, reference Figure 6 As shown in the figure, in the actual preparation process of semiconductor devices, due to different manufacturing requirements, the types of film layers formed on the wafer may also have the following situations: (1) Figure 5 As shown, the same type of film layers are stacked continuously, and other types of film layers are not arranged between the same type of film layers; (2) as Figure 6 As shown, other types of film layers are arranged between the film layers of the same type, as well as other situations not mentioned above.

[0066] Taking the above situation (1) as an example, when using traditional optical measurement, the multi-layer film stacking setting in the grinding area 1 may cause the film layer thickness to increase, affecting the light transmittance of the film layer, and causing inaccurate measurement results. The adjacent interfaces between different types of film layers will produce complex reflection, refraction, scattering and other phenomena, which will further cause inaccurate measurement results. However, the embodiment of the present disclosure does not have similar problems and can overcome the influence of the arrangement rules of the film layers in the grinding area 1 on the measurement accuracy. Using the measurement method of the embodiment of the present disclosure, the instrument for measuring the step value is a step meter or an atomic force microscope. The measurement value depends only on the vertical displacement of the probe or the change in atomic force, and is not limited by the number of adjacent interfaces between different film layers, and thus is not limited by the arrangement rules of the film layers. Therefore, the embodiment of the present disclosure further expands the scope of measurement application.

[0067] Taking the above situation (2) as an example, when measuring it using the traditional optical measurement method, the number of adjacent interfaces between different film layers in the grinding area 1 will further increase compared to situation (1), thereby exacerbating the degree of complex reflection, refraction, scattering and other phenomena. If traditional optical measurement is used, it will further cause inaccurate measurement results. However, the embodiment of the present disclosure does not have similar problems and can overcome the influence of the arrangement rules of the film layers in the grinding area 1 on the measurement accuracy. Using the measurement method of the embodiment of the present disclosure, the instrument for measuring the step value is a step meter or an atomic force microscope. The measurement value depends only on the vertical displacement of the probe or the change in atomic force, and is not limited by the number of adjacent interfaces between different film layers, and thus is not limited by the arrangement rules of the film layers, thereby further expanding the scope of measurement application.

[0068] It should be noted that for different manufacturing purposes, a single type of film layer or multiple types of film layers may be formed at different process stages. When the grinding amount needs to be measured at different process manufacturing stages, the measurement method used in the embodiment of the present disclosure is also applicable.

[0069] Optionally, the number of the semiconductor measurement structures is set to one or more.

[0070] In this way, the number of measurement structures provided by the embodiment of the present disclosure is flexible. Based on different measurement purposes, those skilled in the art can set either a single or multiple measurement structures. When a single measurement structure is set, its position can be set around the core functional area, and the semiconductor measurement structure is interspersed in the core functional area. The semiconductor measurement structure can measure the grinding amount of the semiconductor measurement structure grinding area 1. When part or all of the top surface of the core functional area is at the same height as the top surface of the semiconductor measurement structure, it can also be used as the grinding amount of the part or all of the core functional area. This avoids the problem of setting measurement structures at multiple locations on the wafer to achieve the whole wafer grinding amount measurement. It can simplify the measurement process to a certain extent and save layout area. The area where the semiconductor measurement structure is not set can be fully designed as the core functional area, which is beneficial to reduce the area of ​​the semiconductor measurement structure and improve the storage density of the wafer while ensuring the measurement accuracy.

[0071] Furthermore, when it is necessary to measure the polishing uniformity of the entire wafer, measurement structures are separately installed in different regions of the wafer (i.e., multiple measurement structures are installed). The measurement structure in each region can be used to measure the polishing amount in that region, thereby obtaining the polishing amount of different regions. Therefore, the polishing amount of multiple polishing regions 1 on the wafer can be detected, enabling measurement and analysis of polishing uniformity.

[0072] Specifically, one or more exposure units (shots) are set on the wafer, and each exposure unit is provided with one or more semiconductor measurement structures. Each exposure unit includes at least one core functional area. It should be noted that the exposure unit generally refers to the area covered by the photolithography machine during one exposure on the wafer, which usually needs to be smaller than the wafer size. When one exposure unit is set on the wafer, it means that the wafer is exposed once. When multiple exposure units are set on the wafer, it means that the wafer is exposed multiple times. More specifically, the semiconductor measurement structure can be set between adjacent exposure units or on the cutting path area of ​​the exposure unit.

[0073] Thus, based on different manufacturing processes and manufacturing purposes, the number of exposure units provided by the embodiment of the present disclosure is flexible, and can be set to a single or multiple. The number of semiconductor measurement areas set on the exposure unit is also flexible.

[0074] When the number of exposure units is only one and the number of semiconductor measurement structures on the exposure unit is only one, it is beneficial to simplify the measurement process and improve the storage density of the exposure unit while ensuring the measurement accuracy.

[0075] When there is only one exposure unit and there are multiple semiconductor measurement structures on the exposure unit, it is beneficial to achieve measurement of polishing uniformity analysis of the exposure area.

[0076] When there are multiple exposure units and each exposure unit has a single semiconductor measurement structure, the semiconductor measurement structure of each exposure unit can be used to measure the grinding amount of the corresponding exposure unit. Since the exposure units are usually evenly distributed in the manufacturing process, the grinding amounts of multiple evenly distributed grinding areas 1 on the wafer can be obtained, thereby improving the accuracy of the grinding uniformity analysis.

[0077] When there are multiple exposure units and multiple semiconductor measurement structures on each exposure unit, the semiconductor measurement structure of each exposure unit measures multiple measurement values ​​respectively, thereby further improving the accuracy of polishing uniformity analysis.

[0078] Alternatively, for different manufacturing purposes, multiple CMP processes may be used at different stages. The amount of polishing for each CMP process is measured using one or more semiconductor measurement structures, allowing multiple semiconductor measurement structures to be configured on the wafer. This allows for accurate measurement of the amount of polishing for each CMP process.

[0079] Optional, reference Figure 7 and Figure 8 As shown, the top surface of the groove region 2 may have at least one of the following shapes: annular, stripe, and cross. It should be noted that the terms "annular," "stripe," and "cross" are merely exemplary. The actual top surface shape of the groove region 2 includes, but is not limited to, the aforementioned three shapes. These shapes can be adjusted on the wafer based on actual needs and are not detailed here.

[0080] Optional, reference Figure 9 As shown, the size of the measuring groove 3 is determined by the size of the abrasive particles 4 in the slurry, so that the line width CD of the measuring groove 3 is smaller than the diameter D of the abrasive particles 4 .

[0081] It should be noted that in actual production, due to the different manufacturing processes of the abrasive particles 4 in the grinding liquid, the shape of the abrasive particles 4 may be non-spherical. The abrasive particles 4 in the grinding liquid are equivalent to spherical, and their equivalent diameter can be used as the diameter D of the abrasive particles 4.

[0082] Thus, during the chemical mechanical polishing process, the chemical components in the polishing liquid are used to soften the film layer on the wafer surface. Furthermore, the abrasive particles 4 in the polishing liquid contact the film layer being polished to produce a mechanical action, thereby removing the film layer. If the line width of the measurement groove 3 is smaller than the diameter of the abrasive particles 4, the abrasive particles 4 cannot enter the measurement groove 3 and contact the bottom of the measurement groove 3 (i.e., the top surface of the groove region 2). This prevents the chemical mechanical polishing process from polishing the top surface of the groove region 2, reducing damage to the top surface of the groove region 2 and maintaining the same height before and after the chemical mechanical polishing process. This improves the accuracy of the step difference measurement required before and after the chemical mechanical polishing process, thereby further improving the measurement accuracy of the polishing area 1 or the polishing amount during the chemical mechanical polishing process.

[0083] Optional, reference Figure 10 As shown, the depth of the measuring groove 3 is determined by the size of the abrasive particles 4 in the polishing liquid and the line width of the measuring groove 3, so that the height difference between the lowest point where the abrasive particles 4 penetrate into the measuring groove 3 and the top surface of the polishing area 1 before and after the chemical mechanical polishing process is less than the depth of the measuring groove 3.

[0084] Specifically, Wherein, h1 is the pre-step value between the polishing area 1 and the top surface of the groove area 2 before the chemical mechanical polishing process, h2 is the post-step value between the polishing area 1 and the top surface of the groove area 2 before the chemical mechanical polishing process, r is the radius of the abrasive particle 4 in the polishing liquid, and CD is the line width of the measured groove 3.

[0085] It should be noted that in actual production, due to the different manufacturing processes of the abrasive particles 4 in the grinding liquid, the shape of the abrasive particles 4 may be non-spherical. The abrasive particles 4 in the grinding liquid are equivalent to spherical, and their equivalent radius can be used as the radius r of the abrasive particles 4.

[0086] In this way, when the line width of the measurement groove 3 is smaller than the diameter of the abrasive particle 4 and the abrasive particle 4 cannot enter the measurement groove 3 or the bottom of the measurement groove 3, the depth of the measurement groove 3 is determined by the size of the abrasive particle 4 in the polishing liquid, so that the height difference between the lowest point where the abrasive particle 4 penetrates the measurement groove 3 and the top surface of the polishing region 1 before and after the chemical mechanical polishing process is less than the depth of the measurement groove 3. In this way, the lowest point where the abrasive particle 4 penetrates the measurement groove 3 cannot contact the bottom of the measurement groove 3 (i.e., the top surface of the groove region 2), thereby preventing further chemical mechanical polishing from polishing the top surface of the groove region 2, further reducing damage to the top surface of the groove region 2, and ensuring that the height of the top surface of the groove region 2 remains unchanged before and after the chemical mechanical polishing process. This further improves the accuracy of the step difference measurement required before and after the chemical mechanical polishing process, more accurately measures the actual polishing amount of the polishing region 1, and thus further improves the measurement accuracy of the polishing amount of the polishing region 1 or the chemical mechanical polishing process.

[0087] Combine Figure 11 As shown, the embodiment of the present disclosure provides a method for measuring semiconductor polishing amount, which at least includes:

[0088] S1101, forming a semiconductor measurement structure on a wafer; wherein the semiconductor measurement structure includes at least a trench region 2 and a polishing region 1; a top surface of the polishing region 1 is higher than a top surface of the trench region 2, and a sidewall of the polishing region 1 and a top surface of the trench region 2 enclose a measurement trench 3;

[0089] S1102 , determining the grinding amount of the grinding region 1 by measuring the step difference between the grinding region 1 and the top surface of the region before and after the chemical mechanical polishing process.

[0090] Using the semiconductor grinding amount measurement method provided by the embodiment of the present disclosure, a semiconductor measurement structure is formed on a wafer. The semiconductor measurement structure is formed by a measurement groove 3 formed by the groove area 2 and the grinding area 1. Since the top surface of the grinding area 1 is higher than the top surface of the groove area 2, the grinding area 1 and the groove area 2 are stepped through the measurement groove 3, so that the step value here can be measured by a step meter or an atomic force microscope. Before and after the chemical mechanical polishing process, the step value before and after the step between the top surfaces of the grinding area 1 and the groove area 2 are measured. The grinding amount of the grinding area 1 can be determined by the difference between the step value before and after the step value. This grinding amount can be used as the grinding amount measurement value of the chemical mechanical polishing process. When there are micro-undulations on the bottom surface of the wafer, since the measurement is non-optical, the micro-undulations on the surface of the bottom film layer of the wafer during the measurement process will not cause optical interference (such as interference caused by diffuse reflection due to surface unevenness). Therefore, there is no measurement deviation caused by optical interference, thereby making the measurement result more accurate. Compared to optical metrology, which is limited by the surface uniformity of the underlying film layer and the difficulty measuring metal materials, the measurement process of the disclosed embodiment is not limited by the uniformity of the wafer's underlying film layer, nor is it limited by the film material of the semiconductor measurement structure. Even when optical film layer information of the corresponding film layer is unavailable, the semiconductor measurement structure of the disclosed embodiment can still be used for measurement, thus making the semiconductor measurement structure of the disclosed embodiment more widely applicable. In addition, compared to the equipment cost of optical metrology equipment, the equipment cost of step difference measurement equipment (such as step profilers and atomic force microscopes) is lower, so the disclosed embodiment can reduce costs.

[0091] It should be noted that, in some embodiments, the measurement trench 3 is formed by photolithography and etching. In other embodiments, the measurement trench 3 is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) after photolithography and etching.

[0092] Optionally, before one or more chemical mechanical polishing processes in the wafer manufacturing process, one or more corresponding measuring grooves 3 are formed, and each measuring groove 3 is formed by the side wall of the corresponding grinding area 1 and the top surface of the corresponding groove area 2; by measuring the step difference corresponding to the measuring groove 3 before and after grinding of the corresponding chemical mechanical polishing process, the grinding amount of the corresponding grinding area 1 is determined.

[0093] Because the previous chemical mechanical polishing process may affect the morphology of the measurement groove 3 (e.g., affecting the depth of the measurement groove 3 ), the formation of the corresponding measurement groove 3 is required before each chemical mechanical polishing process. The measurement groove 3 corresponding to the chemical mechanical polishing process only measures the polishing depth of the polishing area 1 before and after the corresponding chemical mechanical polishing process. This helps improve the measurement accuracy of the polishing depth of the polishing area 1 during each chemical mechanical polishing process. In addition, one or more measurement grooves 3 can be provided for each chemical mechanical polishing process, allowing for flexible configuration of the number of measurement grooves 3 and increasing design flexibility.

[0094] Specifically, the desired size of the abrasive particles 4 corresponding to each chemical mechanical polishing process is used to control the process parameters for forming the corresponding measurement grooves 3. More specifically, the process parameters include at least: a line width corresponding to the line width of the measurement grooves 3 in the photolithography process, an etching depth corresponding to the depth of the measurement grooves 3 in the etching process, and an etching line width corresponding to the line width of the measurement grooves 3 in the etching process.

[0095] It should be noted that "the line width corresponding to the line width of the measurement groove 3 in the mask of the photolithography process", "the etching depth corresponding to the depth of the measurement groove 3 in the etching process", and "the etching line width corresponding to the line width of the measurement groove 3 in the etching process" are only exemplary expressions. The actual process parameters for forming the measurement groove 3 include but are not limited to the above three types. The formation process parameters can be adjusted and set according to actual needs, and will not be repeated here.

[0096] In this way, by adjusting the desired size of the abrasive particles 4 in each chemical mechanical polishing process, the formation process parameters of the corresponding measurement groove 3 are controlled so that the line width and depth of the measurement groove 3 meet the aforementioned conditions, thereby preventing the corresponding abrasive particles 4 from entering the measurement groove 3 and preventing the lowest point of the corresponding abrasive particles 4 from contacting the bottom of the measurement groove 3. This reduces the damage of the abrasive particles 4 to the top surface of the groove area 2 during each chemical mechanical polishing process, thereby further improving the measurement accuracy.

[0097] The chemical mechanical polishing process includes multiple pre-processes. Based on their impact on the size and morphology of the measurement trench 3, they are initially divided into a first pre-process and a second pre-process. The first pre-process is a process that affects the morphology of the measurement trench 3 and may cause the measurement trench 3 size to deviate from the expected size. The second pre-process is a pre-process that does not affect the morphology of the measurement trench 3 and can directly form the measurement trench 3 during this process.

[0098] In some embodiments, the first pre-process is, for example, a film deposition process performed after forming the measurement trench 3 to form the device, which reduces the line width and depth of the measurement trench 3. The second pre-process is, for example, a photolithography and etching process for directly forming the measurement trench 3.

[0099] Optionally, forming the measuring groove 3 at least includes: a first preceding process before the chemical mechanical polishing process; before the first preceding process, determining that the preset size of the initial groove is a first size, the first size is the same as the preset size of the measuring groove 3; adjusting the preset size of the initial groove to a second size by a preset change amount of the preset size of the initial groove through the first preceding process, so that the vector sum of the second size and the preset change amount is equal to the first size; forming the initial groove according to the second size; executing the first preceding process to change the actual size of the initial groove from the second size to the first size, thereby forming the measuring groove 3.

[0100] In this way, combined Figure 12 As shown, before the chemical mechanical polishing process, if the measurement groove 3 is formed first and then the first pre-process that affects the shape of the groove is performed, the size of the measurement groove 3 will be affected. For example, the film deposition will make the shape of the measurement groove 3 narrower and shallower (refer to Figure 12 (a) Changed to Figure 12(b) process, that is, h0 becomes h3, CD0 becomes CD3), resulting in the actual size of the measuring groove 3 not meeting the design expectations. Therefore, when designing the measuring groove 3, it is necessary to correct its depth or line width. For example, the correction of the line width of the measuring groove 3 can correct the size corresponding to the line width of the measuring groove on the mask, and the correction of the depth of the measuring groove 3 can correct the etching depth corresponding to the groove in the etching process. Before forming the measuring groove 3, when designing the preset size of the measuring groove 3, first design an initial groove size that is the same as the preset size of the measuring groove 3 (that is, the first size that meets the design expectations, reference Figure 12 (h0 and CD0 in (a)), and then simulate and calculate the influence of the first pre-process on the initial trench morphology (for example, from Figure 12 (a) Changed to Figure 12 In the process of (b), the preset changes △h and △CD are: △h=h3-h0, △CD=CD3-CD0, so that the initial groove shape becomes narrower and shallower. At this time, the initial groove shape needs to be designed to be wider and deeper (that is, it needs to be designed to the second size, refer to Figure 12 (c) h4 and CD4, it is obvious that the second size is not the first size that meets the design expectation of the measured trench 3) in order to offset the influence of the first pre-process on the initial trench morphology. The size of the changed initial trench is the second size, so that the initial trench of the second size is affected by the first pre-process on the morphology of the initial trench (for example, from Figure 12 (c) Changed to Figure 12 (d) process, i.e. h4+△h=h0, CD4+△CD=CD0), to restore the preset size of the measuring groove 3 (i.e. the first size that meets the design expectation, refer to Figure 12 (d) h0 and CD0). After the design is completed, first form the second size as shown in Figure 12 (c) shows the initial trench, which is wider and deeper than the desired measurement trench 3. At this time, the first pre-process is performed again, so that the initial trench of the second size is restored to the desired size (i.e., the first size) of the measurement trench 3 after the influence of the first pre-process on the morphology change of the initial trench (i.e., the sum of the vector of the preset change amount). After the first pre-process is completed, the following is formed. Figure 12The actual dimensions of the measurement trench 3 shown in (d) are consistent with the pre-designed dimensions. Thus, the measurement trench 3 can be formed simultaneously with the core functional area. Specifically, the measurement trench 3 can be designed and completed on a photomask for the core functional area. An initial trench is then etched, for example, during an etching process in the core functional area. Prior to the mechanical polishing process, a first pre-process that alters the initial trench morphology is performed to form the measurement trench 3 for the purpose of forming the core functional area. Since the formation of the measurement trench 3 does not require a separate photomask, the formation process for the measurement trench 3 can be simplified, improving production efficiency and reducing production costs.

[0101] It should be noted that the "first size" and "second size" are merely exemplary expressions. The preset sizes of the initial groove include but are not limited to the above two sizes. The preset sizes can be adjusted according to actual needs and will not be described in detail here.

[0102] Optionally, forming the measurement groove 3 at least includes: performing a second pre-process before the chemical mechanical polishing process; and directly forming the measurement groove 3 in the second pre-process according to a preset size of the measurement groove 3 .

[0103] In this way, the measurement groove 3 can be directly formed in a second pre-process prior to the chemical mechanical polishing process. Since the measurement groove 3 is directly subjected to the chemical mechanical polishing process after formation, the morphology and dimensions of the measurement groove 3 remain unchanged, thereby improving the accuracy of measuring the polishing amount of the polishing area 1 during this chemical mechanical polishing process. In addition, the measurement groove 3 can be designed independently, without having to be designed together with the device mask. If the process flow or process parameters are changed during the device formation process, the final shape of the measurement groove 3 will not be changed. This facilitates greater flexibility in the configuration of the measurement groove 3 formation process.

[0104] It should be noted that the "first pre-process" and "second pre-process" are only exemplary expressions. The pre-process of the chemical mechanical polishing process includes but is not limited to the above two processes. The pre-process can be adjusted and set according to actual needs and will not be repeated here.

[0105] Using the semiconductor measurement structure and semiconductor polishing amount measurement method provided by the embodiments of the present disclosure, a semiconductor measurement structure is formed on a wafer. The semiconductor measurement structure is formed by a measurement groove 3 formed by a groove area 2 and a polishing area 1. Since the top surface of the polishing area 1 is higher than the top surface of the groove area 2, the polishing area 1 and the groove area 2 are stepped through the measurement groove 3, so that the step value here can be measured using a step profiler or an atomic force microscope. Before and after the chemical mechanical polishing process, the step value before and after the step between the top surfaces of the polishing area 1 and the groove area 2 are measured. The polishing amount of the polishing area 1 can be determined by the difference between the step value before and after the step value. This polishing amount can be used as the polishing amount measurement value of the chemical mechanical polishing process. When there are micro-undulations on the bottom surface of the wafer, since the measurement is non-optical, the micro-undulations on the surface of the bottom film layer of the wafer will not cause optical interference (such as interference caused by diffuse reflection due to surface unevenness) during the measurement process. Therefore, there is no measurement deviation caused by optical interference, thereby making the measurement result more accurate. Compared to optical metrology, which is limited by the surface uniformity of the underlying film layer and the difficulty measuring metal materials, the measurement process of the disclosed embodiment is not limited by the uniformity of the wafer's underlying film layer, nor is it limited by the film material of the semiconductor measurement structure. Even when optical film layer information of the corresponding film layer is unavailable, the semiconductor measurement structure of the disclosed embodiment can still be used for measurement, thus making the semiconductor measurement structure of the disclosed embodiment more widely applicable. In addition, compared to the equipment cost of optical metrology equipment, the equipment cost of step difference measurement equipment (such as step profilers and atomic force microscopes) is lower, so the disclosed embodiment can reduce costs.

[0106] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof.

Claims

1. A semiconductor measurement structure, characterized in that: The semiconductor measurement structure is disposed on the wafer, and the semiconductor measurement structure at least includes a groove area and a polishing area; wherein the top surface of the polishing region is higher than the top surface of the groove region, and the sidewall of the polishing region and the top surface of the groove region are combined to form a measuring groove; determining a polishing amount of the polishing area by measuring a step difference between the polishing area and the top surface of the groove area before and after the chemical mechanical polishing process; The size of the measuring groove is determined by the size of the abrasive particles in the grinding liquid during the chemical mechanical polishing process; the depth of the measuring groove is always greater than r is the radius of the abrasive particle in the polishing fluid, and CD is the line width of the measured groove.

2. The semiconductor measurement structure according to claim 1, wherein: The step difference measuring instrument at least includes: a step profiler or an atomic force microscope.

3. The semiconductor measurement structure according to claim 1, wherein: The grinding area is configured as a film layer structure, and the film layer types of the grinding area include a single type or multiple types.

4. The semiconductor measurement structure according to any one of claims 1 to 3, characterized in that: The number of the semiconductor measurement structures is set to be one or more.

5. The semiconductor measurement structure according to any one of claims 1 to 3, characterized in that: The line width of the measuring groove is smaller than the diameter of the abrasive grain.

6. The semiconductor measurement structure according to claim 5, wherein: The depth of the measuring groove is determined by the size of the abrasive particles in the polishing liquid and the line width of the measuring groove, so that the height difference between the lowest point where the abrasive particles penetrate into the measuring groove and the top surface of the polishing area before and after the chemical mechanical polishing process is less than the depth of the measuring groove.

7. A method for measuring semiconductor polishing amount, characterized in that: At least: forming a semiconductor measurement structure on a wafer; wherein the semiconductor measurement structure comprises at least a trench region and a polishing region; a top surface of the polishing region is higher than a top surface of the trench region, and a sidewall of the polishing region and the top surface of the trench region together form a measurement trench; determining a polishing amount of the polishing area by measuring a step difference between the polishing area and a top surface of the area before and after the chemical mechanical polishing process; The size of the measuring groove is determined by the size of the abrasive particles in the grinding liquid during the chemical mechanical polishing process; the depth of the measuring groove is always greater than r is the radius of the abrasive particle in the polishing fluid, and CD is the line width of the measured groove.

8. The measurement method according to claim 7, wherein: At least include: Before one or more chemical mechanical polishing processes in a wafer manufacturing process, one or more corresponding measurement grooves are formed, each of which is formed by the sidewall of the corresponding polishing area and the top surface of the corresponding groove area; The grinding amount of the corresponding grinding area is determined by measuring the step difference corresponding to the measuring groove before and after grinding in the corresponding chemical mechanical polishing process.

9. The measuring method according to claim 7, wherein: Forming a measurement trench at least includes: A first pre-process is also included before the chemical mechanical polishing process; Before the first pre-process, determining a preset size of the initial trench as a first size, the first size being the same as a preset size of the measurement trench; Adjusting the preset size of the initial trench to a second size by performing a preset change in the preset size of the initial trench by the first preceding process, so that a vector sum of the second size and the preset change is equal to the first size; forming an initial groove according to a second size; The first pre-process is performed to change the actual size of the initial trench from the second size to the first size, thereby forming a measurement trench.

10. The measuring method according to claim 7, wherein: Forming a measurement trench at least includes: A second pre-process is also included before the chemical mechanical polishing process; According to the preset size of the measurement trench, the measurement trench is directly formed in the second pre-process.

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