Glow discharge depth spectrum analysis method based on sputtering pit morphology

Abstract

The invention discloses a glow discharge depth spectrum analysis method based on sputtering pit morphology. The method comprises the following steps: carrying out depth spectrum measurement on a to-be-measured sample by adopting a glow discharge spectrometer according to a preset working condition to obtain an actual measurement depth spectrum; performing morphology detection on the to-be-detected sample subjected to depth spectrum measurement to obtain a sputtering pit morphology of the to-be-detected sample; and determining the actual film layer structure of the to-be-measured sample according to the sputtering pit morphology and the actual measurement depth spectrum of the to-be-measured sample. According to the method provided by the invention, the distortion influence on glow discharge depth spectrum analysis caused by unevenness of the sputtering pit is quantitatively analyzed, the depth spectrum analysis process is simplified, and the process of finding the flat sputtering pit as far as possible to reduce errors through multiple experiments is optimized; the invention provides a glow discharge spectrometer depth spectrum quantitative analysis method suitable for sputtering pit morphology in any shape.

Description

Technical Field

[0001] The invention relates to the technical field of glow discharge depth analysis, and in particular to a glow discharge depth spectrum analysis method based on sputtering pit morphology. Background Art

[0002] As an effective material analysis method, glow discharge depth spectrum analysis technology is often used to detect the film distribution of multi-layer thin film materials and determine the actual film structure.

[0003] In the existing glow discharge depth spectrum analysis technology, multiple experiments are often conducted to select working conditions where the sputtering crater surface is relatively flat for sample analysis. The purpose is to reduce the interference caused by the irregular sputtering crater morphology to the depth spectrum analysis, and then infer the film structure of the sample through the depth spectrum.

[0004] However, the existing technology can only be limited to depth spectrum analysis of samples with approximately flat sputtering pits, and it is difficult to effectively carry out analysis work for samples with non-flat sputtering pits that exist in a large number of practical applications. Even if the sputtering pits are as flat as possible and the surface roughness of the sputtering pit bottom is reduced, the impact of tiny unevenness on the depth spectrum data is only ignored, rather than quantitatively analyzing and excluding the impact of the sputtering pit morphology on the depth spectrum sharing, and the actual film layer structure cannot be accurately reflected. Summary of the invention

[0005] The present invention provides a glow discharge depth spectrum analysis method based on sputtering pit morphology to overcome the limitation of the prior art that only flat sputtering pits can be analyzed for depth spectrum. It can perform quantitative analysis based on sputtering pits of arbitrary morphology and accurately determine the actual film layer structure.

[0006] According to one aspect of the present invention, a method for analyzing glow discharge depth spectrum based on sputtering crater morphology is provided, comprising:

[0007] Using a glow discharge spectrometer to measure the depth spectrum of the sample to be tested according to preset working conditions, to obtain the actual measured depth spectrum;

[0008] Performing morphology detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering pit morphology of the sample to be tested;

[0009] The actual film structure of the sample to be tested is determined based on the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested.

[0010] Optionally, a glow discharge spectrometer is used to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum, including:

[0011] A glow discharge spectrometer is used to detect the curve of the spectrum signal intensity of the sample to be tested versus the sputtering time according to the preset gas pressure parameters, sputtering power parameters and sputtering time parameters;

[0012] The actual measured depth spectrum includes a curve of the variation of the spectral signal intensity with the sputtering time and the measured signal intensity at any point in the curve and the corresponding sputtering time.

[0013] Optionally, a morphology test is performed on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater morphology of the sample to be tested, including:

[0014] A step profiler or a topography instrument is used to perform topography detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater topography of the sample to be tested.

[0015] Optionally, determining the actual film structure of the sample to be tested according to the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested includes:

[0016] According to the actual measured depth spectrum, determine the sputtering time of the sample to be tested - test signal intensity curve and the measured signal intensity at any point in the curve and its corresponding sputtering time;

[0017] By performing glow discharge sputtering on a sample of standard thickness under the same working conditions as the sample to be tested, the standard sputtering time from the start of sputtering to complete penetration of the sample is recorded, and the sputtering rate of the corresponding material is obtained by dividing the sample thickness by the standard sputtering time;

[0018] Calculate the sputtering depth value at each time point on the sputtering time-test signal intensity curve according to the sputtering rate of the corresponding material, and convert the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve;

[0019] Fitting the sputtering crater morphology formula through the sputtering crater morphology;

[0020] Construct a signal intensity formula that includes the sputtering crater morphology sub-term;

[0021] The actual film structure is calculated by the signal intensity formula including the sputtering pit morphology sub-item and the sputtering depth-test signal intensity curve;

[0022] The actual film layer structure includes the film layer material and the thickness corresponding to the film layer material.

[0023] Optionally, the sputtering crater morphology formula is:

[0024] ;

[0025] Among them, p is a parameter describing the depth of the sputtering crater, and b is a parameter describing the flatness of the bottom surface of the sputtering crater.

[0026] Optionally, the signal strength formula including the sputtering crater morphology sub-item is:

[0027] ;

[0028] in, is the intensity of the measurement signal in the actual measured depth spectrum; K is a constant; r is the radius of the sputtering crater; is the sputtering rate function; X describes the elements contained in the film layer and the relative content of each element, that is, the actual film layer structure; is the atomic mixing function caused by sputtering, is the sputtering crater morphology function; is the average sputtering rate; t is the sputtering time.

[0029] Optionally, the actual film structure is calculated using a signal intensity formula that includes a sputtering crater morphology sub-item and a sputtering depth-test signal intensity curve, including:

[0030] Obtain the initial value of iteration of the actual membrane structure;

[0031] Substitute the known parameters in the signal intensity formula and the iterative initial values ​​of the actual film structure to calculate the sputtering depth-theoretical signal intensity curve;

[0032] Compare the sputtering depth - theoretical signal intensity curve and the sputtering depth - test signal intensity curve;

[0033] If the error is greater than the standard value, adjust the actual film structure through an iterative method and re-compare the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve;

[0034] If the error is smaller than the standard value, the current iteration value is taken as the actual membrane structure.

[0035] Optionally, obtaining the iterative initial value of the actual membrane structure includes:

[0036] The boundary position of each film layer is defined by the turning point of the signal intensity change on the sputtering depth-signal intensity curve, so as to obtain the thickness of the film layer in the composite film layer structure. The composition of the film layer is determined by referring to the standard signal intensity of the relevant elements. The composition of the film layer and the thickness of the film layer together constitute the iterative initial value of the actual film layer structure.

[0037] Optionally, before determining the actual film structure of the sample to be tested based on the sputtering pit morphology and the actual measured depth spectrum of the sample to be tested, the method further includes: performing error correction processing on the actual measured depth spectrum;

[0038] According to the sputtering crater morphology and actual measured depth spectrum of the sample to be tested, the actual film structure of the sample to be tested is determined, including:

[0039] The actual film structure of the sample to be tested is determined based on the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum after processing.

[0040] Optionally, the error correction processing includes: atomic mixing length correction, sample roughness correction and detector signal depth correction.

[0041] The technical solution of the embodiment of the present invention uses a glow discharge spectrometer to measure the depth spectrum of the sample to be tested according to preset working conditions, obtains the actual measured depth spectrum, and then obtains the sputtering time-test signal intensity curve of the sample to be tested. By performing morphology detection on the sample to be tested after the depth spectrum measurement, the sputtering pit morphology of the sample to be tested is obtained, thereby providing a data basis for the subsequent analysis of the influence of the sputtering pit morphology on the signal intensity. By determining the actual film structure of the sample to be tested based on the sputtering pit morphology of the sample to be tested and the actual measured depth spectrum, a relationship between the film structure including the sputtering pit morphology information and the signal intensity is constructed, and the distortion effect caused by the uneven sputtering pit on the glow discharge depth spectrum analysis is quantitatively analyzed, the depth spectrum analysis process is simplified, and the process of multiple experiments to try to find flat sputtering pits to reduce errors is optimized, providing a glow discharge spectrometer depth spectrum analysis method suitable for sputtering pit morphology of arbitrary shapes.

[0042] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0044] Figure 1 A flow chart of a glow discharge depth spectrum analysis method based on sputtering pit morphology provided in an embodiment of the present invention;

[0045] Figure 2 A flow chart of another glow discharge depth spectrum analysis method based on sputtering pit morphology provided by an embodiment of the present invention;

[0046] Figure 3 A flow chart of another method for analyzing glow discharge depth spectrum based on sputtering crater morphology provided in an embodiment of the present invention;

[0047] Figure 4A flow chart of another method for analyzing glow discharge depth spectrum based on sputtering crater morphology provided in an embodiment of the present invention;

[0048] Figure 5 A flow chart of another method for analyzing glow discharge depth spectrum based on sputtering crater morphology provided in an embodiment of the present invention;

[0049] Figure 6 A flow chart of another method for analyzing glow discharge depth spectrum based on sputtering crater morphology provided in an embodiment of the present invention;

[0050] Figure 7 Schematic diagram for describing the relationship between the flatness of the bottom surface of the sputtering pit, the concave-convex depth parameter and the sputtering pit morphology in an embodiment of the present invention;

[0051] Figure 8 A schematic diagram of the relationship between depth spectrum changes of different tunnel parameters provided by an embodiment of the present invention;

[0052] Fig. 9 A schematic diagram of the relationship between the film layer depth and the signal intensity under the convex pit morphology provided by an embodiment of the present invention;

[0053] Fig.10 A schematic diagram of the changing relationship between film layer depth and signal intensity under pit morphology provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] In one embodiment, Figure 1The present invention provides a flowchart of a method for analyzing a glow discharge depth spectrum based on sputtering pit morphology. This embodiment is applicable to depth spectra with any sputtering pit morphology. Figure 1 As shown, the method includes:

[0057] S110, using a glow discharge spectrometer to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum.

[0058] Among them, the preset working conditions can be understood as a set of instrument operating parameters and related operating conditions that are pre-set according to measurement requirements, sample characteristics, and the instrument's own performance before using the glow discharge spectrometer to perform depth spectrum measurement. By way of example, the preset working conditions may include discharge gas pressure, discharge voltage, discharge current, etc.; the actual measured depth spectrum can be understood as a graph in which the horizontal axis represents the sputtering time and the vertical axis represents the signal intensity corresponding to different elements.

[0059] Specifically, firstly, according to the measurement requirements, sample characteristics and the performance of the instrument itself, the preset working conditions of the glow discharge spectrometer are determined, and the instrument operating parameters (such as discharge gas pressure, discharge voltage, discharge current, etc.) are adjusted to control the sputtering rate. Then, during the measurement, the spectrometer continuously detects the spectral signal intensity of each element at different times (corresponding to different depths), and records the sputtering data with the horizontal axis as the sputtering time and the vertical axis as the element signal intensity. The actual measured depth spectrum includes the sputtering time-test signal intensity curve and the measured signal intensity at any point in the curve and its corresponding sputtering time.

[0060] S120, performing morphology detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater morphology of the sample to be tested.

[0061] Among them, morphology detection can be understood as obtaining the geometric information (such as flatness) of the sputtering crater surface through an image recognition device (such as a topography meter); the sputtering crater morphology can be understood as the geometric shape characteristics and surface conditions left on the surface of the bombarded sample.

[0062] Specifically, the geometric information of the sputtering pit surface is obtained through the image recognition device, and the flatness, shape, diameter, depth and other dimensional data of the sputtering pit are detected to provide a basis for subsequent related analysis and judgment.

[0063] S130, determining the actual film structure of the sample to be tested according to the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested.

[0064] The actual film layer structure can be understood as the thickness, composition and relationship between different film layers in the sample to be tested.

[0065] Specifically, by constructing a relationship between the film layer structure including the sputtering pit morphology information and the signal intensity, the element type and content change information at different sputtering times in the actual measured depth spectrum are analyzed to determine the elements contained in each film layer and the thickness of each film layer.

[0066] The embodiment of the present invention uses a glow discharge spectrometer to perform depth spectrum measurement on the sample to be tested according to preset working conditions, obtains the actual measured depth spectrum, and then obtains the sputtering time-test signal intensity curve of the sample to be tested. By performing morphology detection on the sample to be tested after the depth spectrum measurement, the sputtering pit morphology of the sample to be tested is obtained, thereby providing a data basis for the subsequent analysis of the influence of the sputtering pit morphology on the signal intensity. By determining the actual film structure of the sample to be tested based on the sputtering pit morphology of the sample to be tested and the actual measured depth spectrum, a relationship between the film structure including the sputtering pit morphology information and the signal intensity is constructed, and the distortion effect caused by the uneven sputtering pit on the glow discharge depth spectrum analysis is quantitatively analyzed, the depth spectrum analysis process is simplified, and the process of multiple experiments to try to find flat sputtering pits to reduce errors is optimized, providing a glow discharge spectrometer depth spectrum analysis method suitable for sputtering pit morphology of arbitrary shapes.

[0067] Figure 2 A flowchart of another method for analyzing the depth spectrum of a glow discharge based on the sputtering pit morphology provided in an embodiment of the present invention. The embodiment of the present invention refines or optimizes the above embodiment. Specifically, the above embodiment "S110, using a glow discharge spectrometer to measure the depth spectrum of the sample to be tested according to preset working conditions to obtain an actual measured depth spectrum" is refined, which can be specifically refined as follows:

[0068] A glow discharge spectrometer is used to detect the curve of the spectrum signal intensity of the sample to be tested versus the sputtering time according to the preset gas pressure parameters, sputtering power parameters and sputtering time parameters;

[0069] The actual measured depth spectrum includes a curve of the variation of the spectral signal intensity with the sputtering time and the measured signal intensity at any point in the curve and the corresponding sputtering time.

[0070] like Figure 2 As shown, the method may specifically include the following steps:

[0071] S210, using a glow discharge spectrometer to detect a curve of a spectrum signal intensity of the sample to be tested versus sputtering time according to preset gas pressure parameters, sputtering power parameters and sputtering time parameters.

[0072] Among them, gas pressure parameters can be understood as parameters related to gas pressure, including the type of discharge gas and gas pressure; sputtering power parameters can be understood as parameters including discharge voltage, discharge current, etc. that determine the difficulty of sample atoms to detach from the sample surface and be ionized; sputtering time parameters can be understood as sputtering intensity parameters related to time, including pulse frequency, space ratio and continuous sputtering time.

[0073] Specifically, first determine the gas pressure parameters, sputtering power parameters and sputtering time parameters according to the elements contained in the sample. After setting the operating parameters of the glow discharge spectrometer, the spectrometer continuously detects the spectral signal intensity of each element at different times (corresponding to different depths), and records the sputtering data with the horizontal axis as the sputtering time and the vertical axis as the element signal intensity. The actual measured depth spectrum includes the sputtering time-test signal intensity curve and the measured signal intensity at any point in the curve and its corresponding sputtering time.

[0074] S220, performing morphology detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater morphology of the sample to be tested.

[0075] S230, determining the actual film structure of the sample to be tested according to the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested.

[0076] The embodiment of the present invention ensures the accuracy and reliability of the curve of the variation of the spectral signal intensity of the sample to be measured with the sputtering time obtained during the measurement process by refining the settings of the gas pressure parameter, sputtering power parameter and sputtering time parameter of the glow discharge spectrometer.

[0077] Figure 3 A flowchart of another method for analyzing the depth spectrum of glow discharge based on the sputtering crater morphology provided in an embodiment of the present invention is provided. The embodiment of the present invention refines or optimizes the above embodiment. Specifically, the step "S120, performing morphology detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater morphology of the sample to be tested" in the above embodiment is refined and can be specifically refined as follows:

[0078] A step profiler or a topography instrument is used to perform topography detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater topography of the sample to be tested.

[0079] like Figure 3 As shown, the method may specifically include the following steps:

[0080] S310, using a glow discharge spectrometer to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum.

[0081] S320, using a step meter or a topography meter to perform topography detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater topography of the sample to be tested.

[0082] Among them, the step meter can be understood as an instrument that uses a stylus to measure the surface morphology of a sample; the topography meter can be understood as an instrument that uses optical principles such as optical interference and confocal to obtain information on the surface morphology of a sample.

[0083] Specifically, the geometric information of the sputtering pit surface is obtained through the physical scanning of the probe step meter or the optical scanning topography meter, and the flatness, shape, diameter, depth and other dimensional data of the sputtering pit are detected to provide a basis for subsequent related analysis and judgment.

[0084] S330, determining the actual film structure of the sample to be tested according to the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested.

[0085] The embodiment of the present invention obtains geometric information of the sputtering pit surface through a step meter or a topography meter, detects dimensional data such as flatness, shape, diameter, and depth of the sputtering pit, and provides a basis for subsequent related analysis and judgment.

[0086] Figure 4 A flowchart of another method for analyzing glow discharge depth spectrum based on sputtering crater morphology provided in an embodiment of the present invention, Figure 8 A schematic diagram of the relationship between depth spectra changes of different tunnel parameters provided by an embodiment of the present invention, Fig. 9 A schematic diagram of the relationship between the film layer depth and the signal intensity under the convex pit morphology provided by an embodiment of the present invention, Fig.10 Schematic diagram of the relationship between the film layer depth and signal intensity under the pit morphology provided by the embodiment of the present invention. The embodiment of the present invention refines or optimizes the above embodiment. Specifically, the above embodiment "S130, according to the sputtering pit morphology and the actual measured depth spectrum of the sample to be tested, determine the actual film layer structure of the sample to be tested." is refined and can be specifically refined as follows:

[0087] According to the actual measured depth spectrum, determine the sputtering time of the sample to be tested - test signal intensity curve and the measured signal intensity at any point in the curve and its corresponding sputtering time;

[0088] By performing glow discharge sputtering on a sample of standard thickness under the same working conditions as the sample to be tested, the standard sputtering time from the start of sputtering to complete penetration of the sample is recorded, and the sputtering rate of the corresponding material is obtained by dividing the sample thickness by the standard sputtering time;

[0089] Calculate the sputtering depth value at each time point on the sputtering time-test signal intensity curve according to the sputtering rate of the corresponding material, and convert the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve;

[0090] Fitting the sputtering crater morphology formula through the sputtering crater morphology;

[0091] Construct a signal intensity formula that includes the sputtering crater morphology sub-term;

[0092] The actual film structure is calculated by the signal intensity formula including the sputtering pit morphology sub-item and the sputtering depth-test signal intensity curve;

[0093] The actual film layer structure includes the film layer material and the thickness corresponding to the film layer material.

[0094] like Figure 4 As shown, the method may specifically include the following steps:

[0095] S410, using a glow discharge spectrometer to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum.

[0096] S420, performing morphology detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater morphology of the sample to be tested.

[0097] S430, determining the sputtering time-test signal intensity curve of the sample to be tested and the measured signal intensity at any point in the curve and its corresponding sputtering time according to the actual measured depth spectrum.

[0098] Specifically, by actually measuring the signal intensity related data of each element at different sputtering times recorded in the depth spectrum, the sputtering time is used as the horizontal coordinate, and the corresponding test signal intensity of each element is used as the vertical coordinate to draw the corresponding curve, so as to determine the sputtering time-test signal intensity curve of the sample to be tested, and the corresponding relationship between the horizontal and vertical coordinates is recorded.

[0099] S440. Perform glow discharge sputtering on a sample of standard thickness under the same working conditions as the sample to be tested, record the standard sputtering time from the start of sputtering to complete penetration of the sample, divide the thickness of the sample by the standard sputtering time, and obtain the sputtering rate of the corresponding material.

[0100] Among them, the sample of standard thickness can be understood as a specific sample with a known and precise thickness, and its material is exactly the same as that of the sample to be tested; the sputtering rate of the corresponding material can be understood as the average thickness of the atoms on the surface of the material sputtered per unit time under specific glow discharge working conditions.

[0101] Specifically, first prepare a sample with a standard thickness that is the same material as the sample to be tested. Then, place the sample with standard thickness under the same working conditions as those for glow discharge sputtering of the sample to be tested for sputtering. The working conditions include discharge gas pressure, discharge voltage, discharge current and other related parameters. Record the standard sputtering time from the beginning of sputtering the sample with standard thickness to the final complete penetration of the sample. Finally, divide the thickness of the sample with standard thickness by the recorded standard sputtering time to obtain the sputtering rate of the material.

[0102] S450, calculating the sputtering depth value at each time point on the sputtering time-test signal intensity curve according to the sputtering rate of the corresponding material, and converting the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve.

[0103] The sputtering depth-signal intensity curve can be understood as a relationship curve in which the horizontal axis represents the sputtering depth and the vertical axis represents the signal intensity corresponding to different elements.

[0104] Specifically, based on the known sputtering rate of the corresponding material, the original sputtering time-test signal intensity curve is converted, and the sputtering depth corresponding to the sputtering time is calculated according to the sputtering rate, and then the horizontal axis is replaced from the sputtering time to the sputtering depth.

[0105] S460, fitting the sputtering crater morphology formula through the sputtering crater morphology.

[0106] Among them, the sputtering crater morphology formula can be understood as a mathematical expression used to quantitatively describe the various morphological characteristics of the sputtering crater.

[0107] Specifically, select parameters in the sputtering crater morphology that have a greater impact on the signal intensity (such as parameters of the sputtering crater concave-convex depth) and continuously adjust the parameter values ​​so that the error between the sputtering crater morphology calculated according to the formula and the actual observed sputtering crater morphological feature data is less than a certain standard, thereby completing the fitting of the sputtering crater morphology formula.

[0108] Optional, Figure 7 Schematic diagram of the relationship between the flatness of the bottom surface of the sputtering pit, the concave-convex depth parameter and the sputtering pit morphology in the embodiment of the present invention. The sputtering pit morphology formula is:

[0109] ;

[0110] Among them, p is a parameter describing the depth of the sputtering crater, and b is a parameter describing the flatness of the bottom surface of the sputtering crater.

[0111] Specifically, Figure 7As shown in the figure, the parameters that have a greater impact on the signal intensity include the depth of the sputtering crater p and the flatness of the bottom of the sputtering crater b. When p>1, it is a convex crater, p<1 is a concave crater, and p =1 is a flat crater (No crater effect), that is, the surface is relatively flat, without obvious depressions or protrusions. The flatter the bottom of the sputtering crater, the larger b is. For example, when the pit surface at b = 5 is compared with the pit surface at b = 2, under the same p value condition, the bottom of the sputtering crater at b = 2 is flatter.

[0112] S470. Construct a signal intensity formula including a sputtering crater morphology sub-item.

[0113] The signal strength formula can be understood as a mathematical expression of the relationship between signal strength and related factors.

[0114] Specifically, a mathematical expression for the signal intensity that includes parameters describing the sputtering crater shape (such as concave-convex depth p and bottom surface flatness b) is constructed to provide a theoretical basis for the subsequent quantitative analysis of the effects of different sputtering crater morphologies on signal intensity.

[0115] Optionally, the signal strength formula including the sputtering crater morphology sub-item is:

[0116] ;

[0117] in, is the intensity of the measurement signal in the actual measured depth spectrum; K is a constant; r is the radius of the sputtering crater; is the sputtering rate function; X describes the elements contained in the film layer and the relative content of each element, that is, the actual film layer structure; is the atomic mixing function caused by sputtering, is the sputtering crater morphology function; is the average sputtering rate; t is the sputtering time.

[0118] Specifically, in the above signal intensity expression, K is a fixed coefficient that remains unchanged throughout the calculation process and plays a proportional adjustment role in the signal intensity; the sputtering crater radius r represents the size characteristics of the sputtering crater, and in the integration process represents the contribution of the sputtering crater from the center (r = 0) to the edge (r = 1) to the signal intensity; the sputtering rate function Affected by the actual structure X of the film layer (including the elements contained in the film layer and the relative content of each element) and the radius of the sputtering crater, it reflects the relationship between the sputtering time and the sputtering depth; It shows the relationship between the atomic mixing caused by sputtering and the radius of the sputtering crater; Indicates the actual film structure that changes with the morphology of the sputtering crater; represents the average sputtering rate during the entire sputtering process; t is the sputtering time. The above formula quantifies the signal intensity by integrating the contribution of each position from the center to the edge of the sputtering crater (normalized from 0 to 1), taking into account the influence of multiple factors such as the sputtering crater radius, sputtering rate, film layer structure, atomic mixing, sputtering crater morphology, average sputtering rate and sputtering time on the actual measured signal intensity.

[0119] S480, calculating the actual film structure through the signal intensity formula including the sputtering pit morphology sub-item and the sputtering depth-test signal intensity curve.

[0120] Specifically, select an appropriate initial value of the film structure and substitute it into the signal strength formula to calculate the theoretical signal strength distribution. Compare the theoretical signal strength distribution with the actual signal strength data presented by the sputtering depth-test signal strength curve, and adjust the value of the film structure X according to the signal strength difference.

[0121] For example, the theoretical film structure of the film production process is first substituted into the signal strength formula as the initial iteration value to calculate the theoretical signal strength distribution. Then, the theoretical signal strength distribution is compared with the actual signal strength data in the sputtering depth-test signal strength curve, and the theoretical signal strength distribution is compared with the actual signal strength data in the sputtering depth-test signal strength curve. Figure 8 Schematic diagram of the depth spectrum variation relationship under the tunnel parameters shown and Fig. 9 and Fig.10 The schematic diagram of the relationship between the film layer depth and the signal intensity is shown. According to the values ​​of parameters b and p and the deviation between the theoretical signal intensity and the actual signal intensity, the value of the film layer structure X is adjusted accordingly.

[0122] The embodiment of the present invention determines the sputtering time-test signal intensity curve and construction rate of the sample to be tested, converts the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve, and then obtains the signal intensity change of each element at different depths inside the sample. On this basis, the actual film structure is calculated by constructing a sputtering pit morphology formula and a signal intensity formula containing a sputtering pit morphology sub-item, quantitatively analyzing the distortion effect of the uneven sputtering pit on the glow discharge depth spectrum analysis, simplifying the depth spectrum analysis process, optimizing the process of multiple experiments to try to find a flat sputtering pit to reduce errors, and providing a glow discharge spectrometer depth spectrum analysis method suitable for sputtering pit morphology of arbitrary shapes.

[0123] Figure 5A flowchart of another method for analyzing glow discharge depth spectrum based on sputtering pit morphology is provided in an embodiment of the present invention. The embodiment of the present invention refines or optimizes the above embodiment. Specifically, the above embodiment "S480, calculating the actual film layer structure by a signal intensity formula including a sputtering pit morphology sub-item and a sputtering depth-test signal intensity curve." is refined, which can be specifically refined as follows:

[0124] Obtain the initial value of iteration of the actual membrane structure;

[0125] Substitute the known parameters in the signal intensity formula and the iterative initial values ​​of the actual film structure to calculate the sputtering depth-theoretical signal intensity curve;

[0126] Compare the sputtering depth - theoretical signal intensity curve and the sputtering depth - test signal intensity curve;

[0127] If the error is greater than the standard value, adjust the actual film structure through an iterative method and re-compare the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve;

[0128] If the error is smaller than the standard value, the current iteration value is taken as the actual membrane structure.

[0129] like Figure 5 As shown, the method may specifically include the following steps:

[0130] S510, using a glow discharge spectrometer to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum.

[0131] S520, performing morphology detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater morphology of the sample to be tested.

[0132] S530, determining the sputtering time-test signal intensity curve of the sample to be tested and the measured signal intensity at any point in the curve and its corresponding sputtering time according to the actual measured depth spectrum.

[0133] S540. Perform glow discharge sputtering on a sample of standard thickness under the same working conditions as the sample to be tested, record the standard sputtering time from the start of sputtering to complete penetration of the sample, divide the thickness of the sample by the standard sputtering time, and obtain the sputtering rate of the corresponding material.

[0134] S550, calculating the sputtering depth value at each time point on the sputtering time-test signal intensity curve according to the sputtering rate of the corresponding material, and converting the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve.

[0135] S560, fitting the sputtering crater morphology formula through the sputtering crater morphology.

[0136] S570. Construct a signal intensity formula including a sputtering crater morphology sub-item.

[0137] S580, obtaining the initial value of the iteration of the actual membrane layer structure.

[0138] The initial iteration value of the actual membrane layer structure can be understood as an estimated value of the membrane layer structure initially set to start the iterative calculation in the iterative calculation.

[0139] Specifically, the theoretical value of the prepared membrane layer structure is obtained through existing production information (such as design requirements, material formula, etc.), and the theoretical value is used as the initial value of the iteration of the actual membrane layer structure.

[0140] Optionally, the boundary position of each film layer is defined by the turning point of the signal intensity change on the sputtering depth-signal intensity curve, so as to obtain the thickness of the film layer in the composite film layer structure, and the composition of the film layer is determined with reference to the standard signal intensity of the relevant elements. The composition of the film layer and the thickness of the film layer together constitute the iterative initial value of the actual film layer structure.

[0141] The standard signal intensity of the relevant element can be understood as the typical and representative signal intensity value that a certain element can produce under known experimental conditions or environments; the composition of the film layer can be understood as the elements contained in the film layer and the proportion of the elements;

[0142] Specifically, first, the curve is observed to have obvious turning points at certain specific depth positions along the direction of increasing sputtering depth, and the number of layers of the film layer is determined. Then, the composition of each film layer is determined by referring to the standard signal intensity of the relevant elements. Finally, the film layer composition and the measured film layer thickness together constitute the initial value of the iteration of the actual film layer structure.

[0143] S581. Substitute known parameters in the signal intensity formula and the initial values ​​of the iteration of the actual film structure to calculate the sputtering depth-theoretical signal intensity curve.

[0144] Specifically, the parameters whose specific values ​​have been determined are combined with the iterative initial values ​​of the actual membrane structure, and the corresponding theoretical signal intensity curve is calculated through the signal intensity formula.

[0145] S582. Compare the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve.

[0146] Specifically, the signal intensity error at the same depth is determined by comparing the trends, characteristic points, signal intensity change slopes, and other aspects of the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve.

[0147] S583. If the error is greater than the standard value, adjust the actual film structure through an iterative method, and re-compare the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve.

[0148] The standard value can be understood as the preset allowable error range boundary.

[0149] Specifically, the signal intensity error of the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve at the same depth is first calculated. If the signal intensity error at this depth exceeds the standard value, the actual film layer structure is adjusted using an iterative method. For example, if the content of element A in a certain film layer is 30% before the iteration, during the iterative adjustment, refer to Figure 8 Schematic diagram of the depth spectrum variation relationship under the tunnel parameters shown and Fig. 9 and Fig.10 The relationship between the film depth and the signal intensity is shown in the figure, and the content ratio of element A and / or the thickness of the film layer are appropriately increased or decreased. Then, the adjusted film structure parameters are substituted into the signal intensity formula, and a new sputtering depth-theoretical signal intensity curve is recalculated and compared again. If the error is still greater than the standard value, the iterative process is repeated until the error between the two curves is less than the set standard value.

[0150] S584. If the error is smaller than the standard value, the current iteration value is used as the actual membrane layer structure.

[0151] Specifically, when the error between the two curves is less than the set standard value, the current iteration value consisting of the composition and thickness information of each film layer is output as the actual film layer structure of the sample.

[0152] The embodiment of the present invention simulates the change in signal intensity corresponding to each element at different sputtering depths at the theoretical level, observes the difference between theoretical calculation and actual measurement, finds the signal intensity deviation in a specific depth range, and continuously optimizes and adjusts the actual film layer structure through iteration, thereby providing a glow discharge spectrometer depth spectrum analysis method suitable for sputtering pit morphology of arbitrary shape.

[0153] Figure 6 A flowchart of another glow discharge depth spectrum analysis method based on sputtering crater morphology provided by an embodiment of the present invention is a refinement or optimization of the above embodiment. Specifically, in the above embodiment, before "S130, determining the actual film structure of the sample to be tested based on the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested.", it also includes:

[0154] The actual measured depth spectrum is corrected for errors.

[0155] Based on this, the actual film structure of the sample to be tested can be determined according to the sputtering crater morphology and the actual measured depth spectrum of the sample to be tested, which can be replaced by:

[0156] The actual film structure of the sample to be tested is determined based on the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum after processing.

[0157] like Figure 6 As shown, the method may specifically include the following steps:

[0158] S610, using a glow discharge spectrometer to measure the depth spectrum of the sample to be measured according to preset working conditions to obtain an actual measured depth spectrum.

[0159] S620, performing morphology detection on the sample to be tested after the depth spectrum measurement, to obtain the sputtering crater morphology of the sample to be tested.

[0160] S630: Perform error correction processing on the actual measured depth spectrum.

[0161] The error correction process can be understood as quantifying and eliminating the distortion factors that affect the depth spectrum signal intensity through a mathematical model.

[0162] Specifically, during the measurement process, due to the influence of various physical and chemical processes and instrument-related factors, the signal intensity of the depth spectrum will be disturbed to varying degrees. For example, during the sputtering process, atoms will mix, and this atomic mixing is not uniform and ideal. It will change the original distribution state of each element at different depths, thereby affecting the measured signal intensity; the sample itself may have roughness on the surface, and its uneven surface structure will make the signal generation and propagation process during measurement complicated, resulting in the measured signal intensity not being able to truly reflect the accurate intensity corresponding to the internal element distribution. Based on the above deviations, a corresponding mathematical model is constructed to correct the signal intensity deviation of the actual measured depth spectrum, so that the signal intensity corresponding to each depth in the depth spectrum can accurately restore the true distribution of each element when the sample is not affected by such abnormal sputtering.

[0163] Optionally, the error correction processing includes: atomic mixing length correction, sample roughness correction and detector signal depth correction.

[0164] Among them, the atomic mixing length can be understood as the influence range of the mixing effect between atoms at different depths during sputtering analysis and other processes; the sample roughness can be understood as the flatness of the sample surface; and the detector signal depth can be understood as the thickness range of the detector to obtain the surface signal intensity.

[0165] Specifically, we can construct atomic mixing length , sample roughness and detector signal depth The mathematical model is used to correct the signal intensity deviation of the actual measured depth spectrum, so that the signal intensity corresponding to each depth in the depth spectrum can accurately restore the true distribution of each element in the sample when it is not affected by this abnormal sputtering.

[0166] For example, the atomic mixing length can be calculated by the MRI model , sample roughness and detector signal depth , and correct the actual measured depth spectrum. The expression of normalized signal intensity in the MRI model is:

[0167] ;

[0168] in, It can be understood as the depth Signal strength at Relative to the reference intensity Normalized value (such as the surface or the initial set standard intensity); It can be understood as the original film structure or the material at depth The characteristic distribution function at (the composition ratio of the material); It is a function of depth resolution, which can be understood as the ability of the measurement system to distinguish signals at different depths. It refers to the effect under different depth differences; Indicates that the integral operation is from negative infinity to positive infinity for the current depth Integrate, -∞~+∞ represents the original film structure at different positions in the entire depth range As a function of depth resolution The normalized intensity of the interaction impact.

[0169] Atomic mixing length The depth resolution function is:

[0170] ;

[0171] in, It is the atomic mixing length caused by sputtering. When ions bombard the sample to cause sputtering, atoms will mix within a certain depth range. It means that as the sputtering depth z increases , the measured signal decays exponentially. That is, as the depth increases, the influence of atomic mixing on the measured signal gradually weakens.

[0172] For example, when the ion beam begins to sputter the film, in the area close to the film surface (z is slightly larger than ), the atomic mixing phenomenon is more obvious, and the signal intensity is measured The decay of the signal is relatively slow. As the sputtering depth increases, the atomic mixing length has a great influence on the measurement signal intensity. The impact will be based on Rapid decay.

[0173] Surface roughness The depth resolution function is:

[0174] ;

[0175] in, is the surface roughness, the larger The smaller the value, the more uneven the surface is. A higher value means the surface is relatively flat and the range of roughness variation is small. Indicates surface roughness At different depths The distribution of the . Obeying Gaussian distribution, in actual situations The closer the distribution of Changes in signal strength The more accurate the calculation of the impact is, the more accurate the calculation is. Deviates from Gaussian distribution, then use To calculate the surface roughness Related physical quantities (such as signal strength and the original film structure ), a large error will be introduced.

[0176] Detector signal depth The depth resolution function is:

[0177] ;

[0178] in, It can be understood as a normalization condition, which ensures that the integral of the function is 1 over the entire depth range; It can be understood that as the depth z increases, the probability of deeper atoms being sputtered becomes smaller, and thus the contribution of atoms sputtered from this depth to the measurement signal decreases exponentially.

[0179] S640, determining the actual film structure of the sample to be tested according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum after processing.

[0180] The processed actual measured depth spectrum can be understood as a depth spectrum with signal intensity corrected for distortion.

[0181] Specifically, by constructing a relationship between the film layer structure including the sputtering pit morphology information and the signal intensity after distortion correction, the element type and content change information at different sputtering times in the actual measured depth spectrum are analyzed to determine the elements contained in each film layer and the thickness of each film layer.

[0182] The embodiment of the present invention further improves the accuracy of depth spectrum analysis by correcting other distortion factors that may cause errors in signal intensity in the depth spectrum before determining the actual film structure of the sample to be tested based on the sputtering pit morphology and the actual measured depth spectrum of the sample to be tested.

[0183] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0184] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A glow discharge depth spectrum analysis method based on sputtering pit morphology, characterized in that: include: Using a glow discharge spectrometer to measure the depth spectrum of the sample to be tested according to preset working conditions, to obtain the actual measured depth spectrum; Performing morphology detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater morphology of the sample to be tested; The actual film structure of the sample to be tested is determined according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum.

2. The analysis method according to claim 1, characterized in that The glow discharge spectrometer is used to measure the depth spectrum of the sample to be tested according to the preset working conditions to obtain the actual measured depth spectrum, including: A glow discharge spectrometer is used to detect the curve of the spectrum signal intensity of the sample to be tested versus the sputtering time according to the preset gas pressure parameters, sputtering power parameters and sputtering time parameters; The actual measured depth spectrum includes a curve of the variation of the spectral signal intensity with the sputtering time and the measured signal intensity at any point in the curve and the corresponding sputtering time.

3. The analysis method according to claim 1, characterized in that Performing morphology detection on the sample to be tested after the depth spectrum measurement to obtain the sputtering crater morphology of the sample to be tested includes: A step profiler or a topography instrument is used to perform topography detection on the sample to be tested after the depth spectrum measurement, so as to obtain the sputtering pit topography of the sample to be tested.

4. The analysis method according to claim 1, characterized in that Determining the actual film structure of the sample to be tested according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum, including: Determine the sputtering time-test signal intensity curve of the sample to be tested and the measured signal intensity at any point in the curve and its corresponding sputtering time according to the actual measured depth spectrum; By performing glow discharge sputtering on a sample of standard thickness under the same working conditions as the sample to be tested, recording the standard sputtering time taken from the start of sputtering to complete penetration of the sample, and dividing the thickness of the sample by the standard sputtering time, the sputtering rate of the corresponding material is obtained; Calculating the sputtering depth value at each time point on the sputtering time-test signal intensity curve according to the sputtering rate of the corresponding material, and converting the sputtering time-test signal intensity curve into a sputtering depth-signal intensity curve; Fitting the sputtering crater morphology formula through the sputtering crater morphology; Construct a signal intensity formula that includes the sputtering crater morphology sub-term; Calculate the actual film layer structure by using the signal intensity formula including the sputtering pit morphology sub-item and the sputtering depth-test signal intensity curve; The actual film layer structure includes the film layer material and the thickness corresponding to the film layer material.

5. The analysis method according to claim 4, characterized in that The sputtering crater morphology formula is: ； Among them, p is a parameter describing the depth of the sputtering crater, and b is a parameter describing the flatness of the bottom surface of the sputtering crater.

6. The analysis method according to claim 4, characterized in that The signal strength formula including the sputtering crater morphology sub-item is: ； in, is the intensity of the measurement signal in the actual measured depth spectrum; K is a constant; r is the radius of the sputtering crater; is the sputtering rate function; X Describes the elements contained in the film layer and the relative content of each element, that is, the actual film layer structure; is the atomic mixing function caused by sputtering, is the sputtering crater morphology function; is the average sputtering rate; t is the sputtering time.

7. The analysis method according to claim 4, characterized in that The actual film structure is calculated by the signal intensity formula including the sputtering pit morphology sub-item and the sputtering depth-test signal intensity curve, including: Obtain the initial value of iteration of the actual membrane structure; Substituting known parameters in the signal intensity formula and the iterative initial values ​​of the actual film layer structure, calculating the sputtering depth-theoretical signal intensity curve; comparing the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve; If the error is greater than the standard value, adjust the actual film structure through an iterative method and re-compare the sputtering depth-theoretical signal intensity curve and the sputtering depth-test signal intensity curve; If the error is smaller than the standard value, the current iteration value is taken as the actual membrane structure.

8. The analysis method according to claim 7, characterized in that The iterative initial values ​​for obtaining the actual membrane structure include: The boundary position of each film layer is defined by the turning point of the signal intensity change on the sputtering depth-signal intensity curve, so as to obtain the thickness of the film layer in the composite film layer structure, and the composition of the film layer is determined by referring to the standard signal intensity of the relevant elements. The composition of the film layer and the thickness of the film layer together constitute the iterative initial value of the actual film layer structure.

9. The analysis method according to claim 1, characterized in that Before determining the actual film structure of the sample to be tested according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum, the method further includes: performing error correction processing on the actual measured depth spectrum; Determining the actual film structure of the sample to be tested according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum, including: The actual film structure of the sample to be tested is determined according to the sputtering crater morphology of the sample to be tested and the actual measured depth spectrum after processing.

10. The analysis method according to claim 9, characterized in that The error correction process includes: atomic mixing length correction, sample roughness correction and detector signal depth correction.

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