Acquisition method and determination method of sample sputtering rate

Abstract

The invention discloses a sample sputtering rate obtaining method and a sample sputtering rate measuring method, and relates to the technical field of material detection and analys.Under the condition that an obtained sputtering depth profile meets a target condition, target etching duration when sputtering analysis is conducted to an interface position of a to-be-measured sample is obtained, and the sputtering rate of the to-be-measured sample is measured. And obtaining the etching rate of the to-be-measured sample based on the target etching duration and the thickness of the to-be-measured sample, so that the interface position can be accurately determined, and meanwhile, the accurate target etching moment corresponding to the interface position can be accurately measured on the premise of accurately obtaining the interface position, so that the measurement accuracy is improved. Therefore, the accurate target etching time when sputtering to the interface position is obtained, and the function of accurately measuring the etching rate of the interface position is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of material detection and analysis, and in particular to a method for obtaining and measuring a sputtering rate of a sample. Background Art

[0002] XPS sputtering depth profiling is an important technology for analyzing the chemical composition and structure of material surfaces and near-surface areas. By combining X-ray photoelectron spectroscopy (XPS) with ion sputtering etching technology, this technology can achieve quantitative analysis of element distribution in the depth direction of the material. Since the birth of XPS technology, it has been widely used in materials science, semiconductor industry, corrosion research and other fields. With the development of nanotechnology, the demand for accurate analysis of material surfaces and interfaces is increasing, and XPS sputtering depth profiling technology has become a key tool for studying nanoscale layered materials.

[0003] At present, XPS sputtering depth profiling technology has matured and can provide a depth profiling diagram of the element target signal intensity changing with etching time, which can then be converted into a sample structure diagram of the element target signal intensity changing with thickness. The ISO 17109 standard stipulates that the position of 50% target signal intensity on the sputtering depth profiling distribution diagram is the interface position, which is crucial for the layer structure analysis of nanoscale layered materials. Technological advances have made it possible to accurately obtain the sputtering rate, which is crucial for the accurate conversion and analysis of the depth profiling diagram.

[0004] Although XPS sputtering depth profiling technology has made significant progress, there are still some challenges and shortcomings. First, the data acquisition conditions have a great influence on the determination of the interface position, which directly affects the accuracy of the interface position and chemical composition. It also leads to inaccurate etching or sputtering rates of the interface position in the actual operation process. In addition, changes in sample characteristics that may occur during the sputtering process, such as re-precipitation of sputtered materials, impurities in the ion beam, uneven ion beam intensity, etc., may affect the accuracy of depth profiling. Summary of the invention

[0005] The main purpose of the present invention is to propose a method for obtaining and measuring the sputtering rate of a sample, aiming to solve the problem that the data acquisition conditions in the prior art have a great influence on the determination of the interface position, which directly affects the accuracy of the interface position and chemical composition, and also leads to the technical problem of inaccurate etching or sputtering rate of the obtained interface position during actual operation.

[0006] To achieve the above object, in a first aspect, a method for obtaining a sputtering rate of a sample proposed by the present invention comprises the following steps: Obtaining a sputtering depth profile of the sample to be tested; wherein the sputtering depth profile records a curve of the signal intensity of the target element of the sample to be tested changing with the sputtering time; In the case where the sputtering depth profile diagram meets the target conditions, the target etching time length when the sputtering profile is performed to the interface position of the sample to be tested is obtained; the target conditions include that the sputtering depth profile diagram includes at least 3 substrate layer sampling data and at least 3 to-be-analyzed layer sampling data, there is at least one interface area sampling data between the first target pickup point and the interface point in the sputtering depth profile diagram and between the second target pickup point and the interface point in the sputtering depth profile diagram, the interface point is located at the position corresponding to 50% of the signal intensity in the sputtering depth profile diagram, the first target pickup point is a data point on the change curve at the interface point close to the analysis layer data side, and the second target pickup point is a data point on the change curve at the interface point close to the substrate layer data side; Based on the target etching time and the thickness of the sample to be tested, the etching rate of the sample to be tested is obtained.

[0007] In one embodiment, before the step of obtaining a target etching time when the sputtering depth profiling effect meets the target condition and the sputtering depth profiling reaches the interface position of the sample to be tested, the method further includes: According to the average value of the analysis layer data, a corresponding analysis layer region is determined in the sputtering depth profile; According to the average value of the substrate layer data, the corresponding substrate layer region is determined in the sputtering depth profile.

[0008] In one embodiment, before the step of determining the corresponding analysis layer region in the sputtering depth profile according to the average value of the analysis layer data, the method further comprises: The average value of the signal intensity located in the area above 95% in the sputtering depth analysis graph is taken as the average value of the analysis layer data; Before the step of determining the corresponding base layer region in the sputtering depth profile according to the average value of the base layer data, the method further comprises: The average value of the signal intensity in the area below 5% in the sputtering depth analysis diagram is taken as the average value of the base layer data.

[0009] In one embodiment, the sample to be tested includes a base layer and at least one analysis layer formed on the base layer, the base layer is a silicon plate, and the analysis layer is a silicon dioxide layer.

[0010] In one embodiment, the first target pickup point is located at a position corresponding to 84% of the signal strength in the sputtering depth profile; and the second target pickup point is located at a position corresponding to 16% of the signal strength in the sputtering depth profile.

[0011] In one embodiment, the step of obtaining the sputtering depth profile of the sample to be tested includes: Performing background subtraction operations on the multiple sets of high-resolution narrow-scan spectra collected in sequence to obtain the signal intensity of the target element corresponding to each of the high-resolution narrow-scan spectra and the corresponding sputtering time; A sputtering depth profile of the sample to be tested is obtained according to the obtained signal intensity and the sputtering time.

[0012] Based on the same technical concept, in a second aspect, the present invention also proposes a method for measuring the sputtering rate of a sample to be tested, comprising the following steps: Using a target ion beam to perform a sputtering operation on a sample to be tested, and collecting a depth profile corresponding to the sputtering operation; wherein the sputtering depth profile records the relationship between the signal intensity of the target element of the sample to be tested and the sputtering time; In the case that the sputtering depth profile does not meet the target condition, re-performing the sputtering operation on the sample to be tested and resampling until the sputtering depth profile obtained meets the target condition; The method described in the first aspect is executed to measure the rate of the sample to be tested.

[0013] In one embodiment, when the sputtering depth profile does not meet the target condition, the step of re-performing the sputtering operation on the sample to be tested and resampling until the sputtering depth profile is collected and meets the target condition includes: In the case that the sputtering depth profile does not meet the target condition, a new current sputtering position is set on the sample to be tested; wherein the distance between the current sputtering position and the previous sputtering position is A, and the impact diameter of the sputtering operation is B, A≥2.5B; Re-sputtering the sample to be tested at the current sputtering position and resampling; When the sputtering depth profile diagram obtained by resampling satisfies the standard conditions, sampling is stopped so that the sputtering depth profile diagram obtained by acquisition satisfies the target conditions; wherein the standard conditions include at least three analysis layer data in the analysis layer area of ​​the sputtering depth profile diagram, at least three base layer data in the base layer area of ​​the sputtering depth profile diagram, and at least five interface area data in the interface area of ​​the sputtering depth profile diagram, and the interface area is the area corresponding to the signal intensity of 10% to 90% in the sputtering depth profile diagram.

[0014] In one embodiment, the step of performing a sputtering operation on the sample to be tested using a target ion beam and collecting a depth profile corresponding to the sputtering operation includes: The sample stage with the sample to be tested fixed thereon is placed in the analysis chamber of the XPS analyzer, and the gas extraction operation is performed on the analysis chamber so that the environment in the analysis chamber reaches the preset environmental conditions; wherein the preset environmental conditions are that the air pressure intensity in the analysis chamber is A, A≤ Pa; The target ion beam is used to perform a sputtering operation on the sample to be tested within the preset environmental conditions at a first target interval time, and a depth profile corresponding to the sputtering operation is collected.

[0015] In one embodiment, the step of performing a sputtering operation on the sample to be tested in the preset environmental conditions using the target ion beam at a first target interval time, and collecting depth profiling data corresponding to the sputtering operation includes: Using the target ion beam to perform a sputtering operation on the sample to be tested under the preset environmental conditions with the first target interval duration; According to the thickness of the sample to be tested, the corresponding single collection interval is set; Data is collected on the sample to be tested according to the single collection interval duration to obtain current depth profiling data corresponding to the sputtering operation.

[0016] When the technical solution of the present invention is in use, the target etching time when the sputtering depth analysis diagram obtained satisfies the target conditions is obtained, and the etching rate of the sample to be tested is obtained based on the target etching time and the thickness of the sample to be tested, so that the present invention can accurately determine the interface position. At the same time, on the premise of accurately obtaining the interface position, the precise target etching moment corresponding to the interface position can be accurately measured, and then the accurate target etching time when sputtering to the interface position is obtained, thereby realizing the function of accurately measuring the etching rate of the interface position, avoiding the problem in the prior art that the data acquisition conditions have a great influence on the determination of the interface position, affecting the accuracy of the interface position and chemical state composition, and also leading to the defect of inaccurate etching or sputtering rate of the obtained interface position during actual operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 A flow chart of a method for obtaining a sample sputtering rate provided by the present invention; Figure 2 for Figure 1 Flow chart of step S100 in the example; Figure 3 Flow charts of some specific embodiments of the method for obtaining the sputtering rate of a sample provided by the present invention; Figure 4 A flow chart of a method for measuring the sputtering rate of a sample to be tested provided by the present invention; Figure 5 for Figure 4 Flow chart of step A200 in the example; Figure 6 for Figure 4 Flow chart of step A100 in the example; Figure 7 for Figure 6 Flow chart of step A120 in the example; Figure 8 A sputtering depth profile diagram of an example of the present invention; Fig. 9 A schematic diagram showing the interface position in a sputtering depth profile diagram according to an example of the present invention; Fig.10 This is the collected Si2p high-resolution narrow scan spectrum without optimization; Fig.11 This is the optimized Si2p high-resolution narrow scan spectrum collected.

[0019] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] The invention provides a method for obtaining the sputtering rate of a sample.

[0024] See also Figures 1 to 11 For ease of understanding, the method for obtaining the sputtering rate of the sample includes the following steps: S100, obtaining a sputtering depth profile of a sample to be tested; wherein the sputtering depth profile records a curve of a signal intensity of a target element of the sample to be tested changing with the sputtering time.

[0025] In this example, see Figures 8 to 11The example sputtering depth profile diagram is a change curve diagram of each sputtering operation time and the signal intensity of the target element at the corresponding time when the sputtering operation is performed on the sample to be tested. The change curve diagram is a linear change diagram, and in the sputtering depth profile diagram, the sputtering time is the horizontal coordinate, the signal intensity of the target element is the vertical coordinate, the signal intensity is the vertical coordinate, and the intersection of the horizontal coordinate and the vertical coordinate is the coordinate origin. The signal intensity is expressed in percentage, that is, the signal intensity range is 0% to 100%. In the sputtering depth profile, the signal intensity of the target element corresponding to each sputtering moment is obtained in the following manner: taking the sample to be tested with a silicon dioxide layer formed on a silicon plate as an example, the target element is the oxygen element O, that is, the signal intensity of the oxygen element needs to be measured. The specific method is to first start the sputtering operation on the surface of the silicon dioxide. During the sputtering operation, the O1s high-resolution narrow-scan spectrum of the O element in the silicon dioxide layer is first collected, and the collected O1s high-resolution narrow-scan spectrum is matched one by one with the corresponding sputtering moment until the sputtering operation of the silicon dioxide layer and the silicon plate is completed, and the collection of the O1s high-resolution narrow-scan spectrum at all sputtering moments is completed. After the collection of the high-resolution narrow-scan spectrum is completed, the background subtraction operation is performed on the collected O1s high-resolution narrow-scan spectrum in turn to obtain the signal intensity of the O element corresponding to each sputtering moment. After obtaining the signal intensity of the O element corresponding to all sputtering moments, the sputtering depth profile is drawn according to the corresponding relationship between the obtained signal intensity of all O elements and the corresponding sputtering moments.

[0026] Of course, it should be clearly stated that in this embodiment, in order to facilitate a better understanding of the present invention, please continue to refer to Figure 8 In the sputtering depth profile, it can be seen that there are two areas where the normalized intensity (i.e., the signal intensity of the O element) approaches the horizontal line and the sudden drop recorded in the sputtering depth profile. In order to facilitate the understanding of the sputtering depth profile of the example in this embodiment, the area where the signal intensity is above 0.95 (i.e., 95%) is taken as the area where the silicon dioxide layer is located, and the area below 0.05 (5%) is taken as the area where the silicon plate is located. In order to better implement the present invention, the area corresponding to 0.16 (i.e., 16%) to 0.84 (i.e., 84%) is taken as the interface area. In this way, the curve relationship between the O element-sputtering time corresponding to the analysis layer, the interface area, and the silicon plate layer can be obtained from the sputtering depth profile in the specific implementation.

[0027] S200, when the sputtering depth profile diagram satisfies the target conditions, obtaining the target etching time when the sputtering profile is performed to the interface position of the sample to be tested; the target conditions include that the sputtering depth profile diagram includes at least 3 substrate layer sampling data and at least 3 to-be-analyzed layer sampling data, there is at least one interface area sampling data between the first target pickup point and the interface point in the sputtering depth profile diagram and between the second target pickup point and the interface point in the sputtering depth profile diagram, the interface point is located at the position corresponding to 50% of the signal intensity in the sputtering depth profile diagram, the first target pickup point is a data point on the change curve at the interface point close to the analysis layer data side, and the second target pickup point is a data point on the change curve at the interface point close to the substrate layer data side; In this embodiment, in order to more clearly understand the present invention, in specific use, the sputtering time corresponding to the signal intensity of 50% can be determined from the sputtering depth profile diagram, and the O1s high-resolution narrow-scan spectrum corresponding to the sputtering time can be used as the high-resolution narrow-scan spectrum of the interface point. On this basis, the first target pickup point and the second target pickup point are respectively obtained from the sputtering depth profile diagram. Among them, the first target pickup point is a data point close to the analysis layer (i.e., silicon dioxide layer) in the signal intensity-sputtering time curve of the O element. More specifically, the data point should be located in the interface region, and the first target pickup point is a data point in the segment where the signal intensity tends to linearly decrease. The second target pickup point is a data point close to the base layer (i.e., silicon plate) in the signal intensity-sputtering time curve of the O element. More specifically, the data point should be located in the interface region, and the second target pickup point is a data point in the segment where the signal intensity tends to linearly decrease. In order to more clearly understand the first target pickup point and the second target pickup point, please continue to refer to Figure 8 ,from Figure 8It can be seen without a doubt that the relationship between the signal intensity of the O element and the sputtering time is that as the sputtering time increases, it starts to show a parabolic downward trend from the initial horizontal state. After a certain sputtering time, the relationship between the signal intensity of the O element and the sputtering time shows a linear downward trend. When it drops to another signal intensity, the relationship between the signal intensity of the O element and the sputtering time begins to show a parabolic downward trend until it reaches a new horizontal state. According to the relationship curve between the signal intensity of the O element and the sputtering time, combined with the O1s high-resolution narrow-scan spectrum corresponding to each sputtering time and the known structure of the sample to be tested (i.e., the silicon dioxide layer formed on the silicon plate in the example of this embodiment), it can be clearly seen that when the sputtering operation is performed, since the silicon dioxide layer on the surface is sputtered first, at this time, the content of the O element in the silicon dioxide layer is higher than the content of the O element in the silicon plate, and the O1s high-resolution narrow-scan spectrum and the corresponding signal intensity of the O element are high, that is, the signal intensity of the O element at this time is close to 100%. However, the data obtained from the test will not be as smooth as the theoretical data. Therefore, in actual operation, the area where the signal intensity of the O element is above 95% is regarded as the silicon dioxide layer, and the area below 5% is regarded as the silicon plate layer.

[0028] In order to more clearly select the first target pickup point and the second target pickup point, when in use, the intersection point from the initial horizontal state to the gradually declining parabolic trend to the linear declining trend (the position corresponding to the signal strength of 0.84 in the sputtering depth profile diagram) is used as the first target pickup point, and the relationship between the signal intensity of the O element and the sputtering time from the end point approaching the linear decline to the intersection point of the parabolic downward trend (the position corresponding to the signal strength of 0.16 in the sputtering depth profile diagram) is used as the second target pickup point.

[0029] It can be further clarified that, in this embodiment, the first target pick-up point and the interface point in the sputtering depth profile are exemplified (i.e., the signal strength is between 0.84 and 0.5); the second target pick-up point and the interface point in the sputtering depth profile are exemplified (i.e., the signal strength is between 0.5 and 0.16). The analysis layer data exemplified in this embodiment is the high-resolution narrow-scan spectrum of each element (mainly O and Si) of the silicon dioxide layer collected during the sputtering operation, and the base layer data exemplified is the high-resolution narrow-scan spectrum of the silicon plate collected.

[0030] S300: Obtaining an etching rate of the sample to be tested based on the target etching time and the thickness of the sample to be tested.

[0031] Of course, in order to facilitate the understanding of the present invention, in a specific implementation, the etching rate of the sample to be tested can be obtained by dividing the thickness of the sample to be tested by the target etching time.

[0032] In this embodiment, by obtaining a sputtering depth profile that satisfies the target conditions, the target etching time when the sputtering is profiled to the interface position of the sample to be tested is obtained, and the etching rate of the sample to be tested is obtained based on the target etching time and the thickness of the sample to be tested, so that the present invention can accurately determine the interface position. At the same time, under the premise of accurately obtaining the interface position, the precise target etching moment corresponding to the interface position can be accurately measured, and then the accurate target etching time when sputtering to the interface position is obtained, thereby realizing the function of accurately measuring the etching rate at the interface position, avoiding the problem in the prior art that the data acquisition conditions have a great influence on the determination of the interface position, affecting the accuracy of the interface position and chemical composition, and also leading to the defect of inaccurate etching or sputtering rate at the interface position obtained during actual operation.

[0033] In some specific embodiments, before step S200, the method further includes: S500, determining a corresponding analysis layer region in the sputtering depth profile according to an average value of the analysis layer data; In this embodiment, the average value of the analysis layer data is the average value of the signal intensity of the O element, which is obtained by averaging the data with the signal intensity of the O element being above 95%.

[0034] S600 , determining a corresponding base layer region in the sputtering depth profile according to an average value of the base layer data.

[0035] In this embodiment, the average value of the base layer data is the average value of the signal intensity of the O element, which is obtained by averaging the data whose signal intensity of the O element is below 5%.

[0036] In one embodiment, before step S500, the method further includes: S700, taking the average value of the signal intensities located in the area above 95% in the sputtering depth analysis graph as the average value of the analysis layer data; Before step S600, the method further includes: S800, taking the average value of the signal intensity in the area below 5% in the sputtering depth analysis diagram as the average value of the base layer data.

[0037] In this embodiment, the analysis layer area (i.e., the silicon dioxide layer exemplified in this embodiment) and the base layer area (i.e., the silicon plate layer) are delineated according to the signal intensity in the sputtering depth profile diagram, so that the signal distribution of the target element can be accurately determined during specific use of the present invention, and the influence of the data on the determination of the interface position can be avoided.

[0038] In one embodiment, the sample to be tested includes a base layer and at least one analysis layer formed on the base layer, the base layer is a silicon plate, and the analysis layer is a silicon dioxide layer.

[0039] In one embodiment, the first target pickup point is located at a position corresponding to 84% of the signal strength in the sputtering depth profile; and the second target pickup point is located at a position corresponding to 16% of the signal strength in the sputtering depth profile.

[0040] In some optional embodiments, step S100 includes: S110, performing background subtraction operations on the multiple sets of high-resolution narrow-scan spectra collected in sequence to obtain the signal intensity of the target element corresponding to each of the high-resolution narrow-scan spectra and the corresponding sputtering time; In this embodiment, the background subtraction operation exemplified is a prior art, which is only applied in this embodiment without any improvement or design for the specific process, so it will not be described in detail here.

[0041] S120 , obtaining a sputtering depth profile of the sample to be tested according to the obtained signal intensity and the sputtering time.

[0042] Based on the same technical concept, in a second aspect, the present invention also proposes a method for measuring the sputtering rate of a sample to be tested, comprising the following steps: A100, using a target ion beam to perform a sputtering operation on a sample to be tested, and collecting a depth profile corresponding to the sputtering operation; wherein the sputtering depth profile records the relationship between the signal intensity of the target element of the sample to be tested and the sputtering time; In this embodiment, the sputtering depth profile diagram of the example is similar to the sputtering depth profile diagram of the example in the previous embodiment. Figure 1 The acquisition process is the same and will not be repeated here.

[0043] Of course, it can be further explained that, in this embodiment, when collecting high-resolution narrow-scan spectra during the sputtering process, the collection interval of the single-layer high-resolution narrow-scan spectra can be determined according to the thickness of the sample to be tested. The specific determination method can be referred to Table 1.

[0044] Table 1 shows the time interval for collecting single high-resolution narrow scan spectra for retrieval depth analysis of samples of different thicknesses.

[0045]

[0046] A200, when the sputtering depth profile does not meet the target condition, re-perform the sputtering operation on the sample to be tested and resample until the sputtering depth profile obtained meets the target condition; In this embodiment, when resampling, it is first necessary to determine the actual interval of collecting high-resolution narrow-scan spectra during resampling. More specifically, the time interval for collecting high-resolution narrow-scan spectra is set to collect at least three high-resolution narrow-scan spectra in the analysis layer region (i.e., silicon dioxide layer) and the substrate region (i.e., silicon plate), and collect at least five high-resolution narrow-scan spectra in the interface region. In this way, the present invention can have sufficient signal strength during specific implementation, thereby improving the accuracy of the sputtering depth profile.

[0047] Of course, in order to further clarify the present invention, in the specific implementation, if data collection is performed at each sputtering moment, the amount of data collected will be very large, which will seriously affect the test efficiency. Therefore, in specific use, data collection can be performed according to the set interval duration.

[0048] A300. Execute the method described in the first aspect to determine the rate of the sample to be tested.

[0049] In this embodiment, when the sputtering depth profile does not meet the target conditions, the acquired signal strength and the number of times the high-resolution narrow-scan spectra are collected are optimized so that more high-resolution narrow-scan spectra can fall into the corresponding area, thereby improving the accuracy of the sputtering depth profile of the target element, thereby making the corresponding time of the interface point more accurate, thereby ensuring the accuracy of the rate of the sample to be tested.

[0050] It can be further explained that, in this embodiment, since the sputtering depth profile is obtained by using the Shirley method to deduct the background from the collected high-resolution narrow-scan spectrum to determine the element spectrum peak area (i.e., signal intensity), the sputtering depth profile cannot completely present a state of first extending horizontally, then linearly decreasing, and finally extending horizontally. This makes the determination of the interface point inaccurate because the interface point is the position of the sputtering moment corresponding to 50% of the signal intensity. Therefore, improving the curve accuracy of the sputtering depth profile can improve the determination accuracy of the interface point.

[0051] In one embodiment, step A200 includes: A210, when the sputtering depth profile does not meet the target condition, setting a new current sputtering position on the sample to be tested; wherein the distance between the current sputtering position and the previous sputtering position is A, and the impact diameter of the sputtering operation is B, A≥2.5B; A220, re-sputtering the sample to be tested at the current sputtering position and resampling; A230. When the sputtering depth profile diagram obtained by resampling satisfies the standard conditions, sampling is stopped so that the sputtering depth profile diagram obtained by acquisition satisfies the target conditions; wherein the standard conditions include at least three analysis layer data in the analysis layer area of ​​the sputtering depth profile diagram, at least three base layer data in the base layer area of ​​the sputtering depth profile diagram, and at least five interface area data in the interface area of ​​the sputtering depth profile diagram, and the interface area is the area corresponding to the signal intensity of 10% to 90% in the sputtering depth profile diagram.

[0052] In one embodiment, step A100 includes: A110, placing the sample stage with the sample to be tested fixed in the analysis chamber of the XPS analyzer, and performing gas extraction operation on the analysis chamber to make the environment in the analysis chamber reach the preset environmental conditions; wherein the preset environmental conditions are that the air pressure intensity in the analysis chamber is A, A≤ Pa; A120. Use the target ion beam to perform a sputtering operation on the sample to be tested within the preset environmental conditions at a first target interval time, and collect a depth profile corresponding to the sputtering operation.

[0053] In one embodiment, step A120 includes: A121, using the target ion beam to perform a sputtering operation on the sample to be tested in the preset environmental condition with the first target interval duration; A122. According to the thickness of the sample to be tested, set the corresponding single collection interval time; A123. Collect data on the sample to be tested according to the single collection interval duration to obtain current depth profiling data corresponding to the sputtering operation.

[0054] Of course, in order to facilitate a clearer understanding of the present invention, the present invention is further explained by taking the rapid confirmation of the interface position of the silicon dioxide standard material (GBW13971 52.61nm) on the silicon wafer as an example, and the specific process is as follows: Use clean tweezers and conductive carbon glue to quickly fix the sample on the sample stage and place it in the spectrometer sampling chamber for pre-vacuuming; after the vacuum meets the spectrometer sample transfer requirements, transfer it to the analysis chamber.

[0055] Ion beam alignment.

[0056] Depth profiling: Initial analysis: An Ar+ beam with an ion beam energy of 1000 eV and a beam current density of 1 A / m2 was used to perform depth profiling of the sample at a fixed sputtering time interval of 100 s. A monochromatized Al target (corresponding target energy of 1486.6 eV) and a 200µm beam spot were used for data acquisition to collect high-resolution narrow-scan spectrum data of the target element O1s. The pass energy was 100 eV, the number of acquisitions was 1, the step size was 0.2 eV, and the data acquisition range was 525 eV ~ 545 eV. The experiment was stopped when the oxygen content relative to silicon was less than 5% and was basically stable.

[0057] According to the changing trend of the signal intensity corresponding to the O1s high-resolution narrow scan spectrum relative to the etching time, the preliminary layer structure information of the sample was obtained. By observing the data, it can be seen that the interface area corresponding to the signal intensity of 16% to 84% is roughly between 350 s and 450 s.

[0058] By observing the data, it was confirmed that the data did not simultaneously meet the requirements of at least 3 data points for the silicon dioxide layer and the silicon plate layer; and at least 1 data point for each of the interface areas with signal strengths of 16% to 50% and 50% to 84%. Deep profiling experiment optimization is required.

[0059] Determination of sample interface position: By observing the changing trend of the signal intensity corresponding to the oxygen element with the sputtering time, it can be known that 16% to 84% of the interface area is in the region of 372 s to 430 s. The sputtering time corresponding to the interface position is linearly calculated to be 401 s.

[0060] Sputtering rate determination: The sputtering rate is calculated using the sputtering time corresponding to the film thickness and interface position.

[0061] Of course, in order to further understand the present invention, please continue to refer to Fig.10 , Fig.11 ; Six typical laboratories (including all XPS manufacturers on the market, see Table 2 for specific test conditions) were selected for multi-laboratory comparison. The comparison object was to obtain the film thickness of the test sample through the etching rate. Each laboratory collected data three times.

[0062] Table 2 Comparison of test parameters among multiple laboratories.

[0063]

[0064] The final depth analysis shows the film thickness and interface thickness before and after optimization. Fig.11As shown. Observation of the data shows that before optimization, the film thickness between laboratories fluctuated greatly, ranging from 87.9nm to 124.4nm; and the film thickness within the laboratory still fluctuated greatly, with the film thickness corresponding to the interface position of Laboratory No. 2 ranging from 88.3nm to 116.5nm; after optimization, the film thickness within the laboratory and between multiple laboratories had good repeatability (between 100.5nm and 107.7nm), and the data consistency was effectively improved. The actual sample to be tested is a standard material (GBW13973) with a silicon dioxide film thickness of 101.5nm. Compared with the actual film thickness of the sample of 101.5nm, the accuracy of the optimized test results is guaranteed.

[0065] observe Fig.11 The Si2p spectra corresponding to the interface positions obtained before and after optimization show that, in addition to the surface silicon dioxide and substrate elemental silicon, the Si2p spectrum peaks corresponding to the interface positions obtained after optimization also have obvious spectrum peaks of the intermediate oxidation state, which can better reflect the interface chemical state information.

[0066] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for obtaining a sample sputtering rate, characterized in that: The steps include: Obtaining a sputtering depth profile of the sample to be tested; wherein the sputtering depth profile records a curve of the signal intensity of the target element of the sample to be tested changing with the sputtering time; In the case where the sputtering depth profile diagram meets the target conditions, the target etching time length when the sputtering profile is performed to the interface position of the sample to be tested is obtained; the target conditions include that the sputtering depth profile diagram includes at least 3 substrate layer sampling data and at least 3 to-be-analyzed layer sampling data, there is at least one interface area sampling data between the first target pickup point and the interface point in the sputtering depth profile diagram and between the second target pickup point and the interface point in the sputtering depth profile diagram, the interface point is located at the position corresponding to 50% of the signal intensity in the sputtering depth profile diagram, the first target pickup point is a data point on the change curve at the interface point close to the analysis layer data side, and the second target pickup point is a data point on the change curve at the interface point close to the substrate layer data side; Based on the target etching time and the thickness of the sample to be tested, the etching rate of the sample to be tested is obtained.

2. The method for obtaining the sample sputtering rate according to claim 1, characterized in that: Before the step of obtaining a target etching time when the sputtering depth profiling effect meets the target condition and the sputtering depth profiling effect reaches the interface position of the sample to be tested, the method further includes: According to the average value of the analysis layer data, a corresponding analysis layer region is determined in the sputtering depth profile; According to the average value of the substrate layer data, the corresponding substrate layer region is determined in the sputtering depth profile.

3. The method for obtaining the sample sputtering rate according to claim 2, characterized in that: Before the step of determining the corresponding analysis layer region in the sputtering depth profile according to the average value of the analysis layer data, the method further includes: The average value of the signal intensity located in the area above 95% in the sputtering depth analysis graph is taken as the average value of the analysis layer data; Before the step of determining the corresponding base layer region in the sputtering depth profile according to the average value of the base layer data, the method further comprises: The average value of the signal intensity in the area below 5% in the sputtering depth analysis diagram is taken as the average value of the base layer data.

4. The method for obtaining the sample sputtering rate according to claim 1, characterized in that: The sample to be tested includes a base layer and at least one analysis layer formed on the base layer, the base layer is a silicon plate, and the analysis layer is a silicon dioxide layer.

5. The method for obtaining the sample sputtering rate according to claim 1, characterized in that: The first target pickup point is located at a position corresponding to 84% of the signal intensity in the sputtering depth profile; the second target pickup point is located at a position corresponding to 16% of the signal intensity in the sputtering depth profile.

6. The method for obtaining the sample sputtering rate according to claim 1, characterized in that: The step of obtaining the sputtering depth profile of the sample to be tested includes: Performing background subtraction operations on the multiple sets of high-resolution narrow-scan spectra collected in sequence to obtain the signal intensity of the target element corresponding to each of the high-resolution narrow-scan spectra and the corresponding sputtering time; A sputtering depth profile of the sample to be tested is obtained according to the obtained signal intensity and the sputtering time.

7. A method for measuring the sputtering rate of a sample to be tested, characterized in that: The steps include: Using a target ion beam to perform a sputtering operation on a sample to be tested, and collecting a depth profile corresponding to the sputtering operation; wherein the sputtering depth profile records the relationship between the signal intensity of the target element of the sample to be tested and the sputtering time; In the case that the sputtering depth profile does not meet the target condition, re-performing the sputtering operation on the sample to be tested and resampling until the sputtering depth profile obtained meets the target condition; The method according to any one of claims 1 to 6 is performed to measure the rate of the sample to be tested.

8. The method for measuring the sputtering rate of a sample to be tested as claimed in claim 7, characterized in that: When the sputtering depth profile does not meet the target condition, the step of re-performing the sputtering operation on the sample to be tested and resampling until the sputtering depth profile is collected and meets the target condition comprises: In the case that the sputtering depth profile does not meet the target condition, a new current sputtering position is set on the sample to be tested; wherein the distance between the current sputtering position and the previous sputtering position is A, and the impact diameter of the sputtering operation is B, A≥2.5B; Re-sputtering the sample to be tested at the current sputtering position and resampling; When the sputtering depth profile diagram obtained by resampling satisfies the standard conditions, sampling is stopped so that the sputtering depth profile diagram obtained by acquisition satisfies the target conditions; wherein the standard conditions include at least three analysis layer data in the analysis layer area of ​​the sputtering depth profile diagram, at least three base layer data in the base layer area of ​​the sputtering depth profile diagram, and at least five interface area data in the interface area of ​​the sputtering depth profile diagram, and the interface area is the area corresponding to the signal intensity of 10% to 90% in the sputtering depth profile diagram.

9. The method for measuring the sputtering rate of a sample to be tested according to claim 7, characterized in that: The step of performing a sputtering operation on the sample to be tested using a target ion beam and collecting a depth profile corresponding to the sputtering operation includes: The sample stage with the sample to be tested fixed thereon is placed in the analysis chamber of the XPS analyzer, and the gas extraction operation is performed on the analysis chamber so that the environment in the analysis chamber reaches the preset environmental conditions; wherein the preset environmental conditions are that the air pressure intensity in the analysis chamber is A, A≤ Pa; The target ion beam is used to perform a sputtering operation on the sample to be tested within the preset environmental conditions at a first target interval time, and a depth profile corresponding to the sputtering operation is collected.

10. The method for measuring the sputtering rate of a sample to be tested according to claim 9, characterized in that: The step of performing a sputtering operation on the sample to be tested in the preset environmental conditions using the target ion beam at a first target interval time, and collecting depth profiling data corresponding to the sputtering operation, comprises: Using the target ion beam to perform a sputtering operation on the sample to be tested under the preset environmental conditions with the first target interval duration; According to the thickness of the sample to be tested, the corresponding single collection interval is set; Data is collected on the sample to be tested according to the single collection interval duration to obtain current depth profiling data corresponding to the sputtering operation.

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