WO2021117203A1

WO2021117203A1 - Surface analysis method, surface analysis system, and surface analysis program

Info

Publication number: WO2021117203A1
Application number: PCT/JP2019/048822
Authority: WO
Inventors: 勇貴新井
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2021-06-17
Also published as: JP7070809B2; JPWO2021117203A1; KR20220103732A

Abstract

A surface analysis method according to one embodiment comprises: a step for acquiring a force curve based on a measurement of a sample surface by means of a scanning-type probe microscope provided with a probe; a step for calculating a differential curve by first-order-differentiating the force curve by a probe-surface distance that is the distance between the probe and the surface; a step for calculating, on the basis of the differential curve, the distance from the sample surface to the farthest peak as a breaking length of an organic material forming the sample surface; and a step for outputting the breaking length.

Description

Surface analysis methods, surface analysis systems, and surface analysis programs

One aspect of this disclosure relates to surface analysis methods, surface analysis systems, and surface analysis programs.

Conventionally, a method for analyzing the surface of a sample containing an organic material has been known. For example, Patent Document 1 describes a method for measuring mechanical characteristics, which comprises measuring using a sample having a thickness determined based on the size of a structure in a polymer composite material. This document also describes that an atomic force microscope (AFM) can be used to measure mechanical properties such as hardness and frictional force on the surface of a sample.

JP-A-2018-178016

A method for analyzing the organic material formed on the surface of the sample in more detail is desired.

The surface analysis method according to one aspect of the present disclosure is a probe that is the distance between the probe and the sample surface and the step of acquiring a force curve based on the measurement of the sample surface by a scanning probe microscope equipped with a probe. The step of calculating the differential curve by first-order differentiating the force curve according to the inter-surface distance, and the distance from the sample surface to the farthest peak based on the differential curve, the breaking length of the organic material forming the sample surface. The step of calculating as and the step of outputting the breaking length are included.

The surface analysis system according to one aspect of the present disclosure includes at least one processor. At least one processor obtains a force curve based on the measurement of the sample surface by a scanning probe microscope equipped with a probe, and sets the force curve by the probe-surface distance, which is the distance between the probe and the sample surface. A differential curve is calculated by order differentiation, and the distance from the sample surface to the farthest peak is calculated as the breaking length of the organic material forming the sample surface based on the differential curve, and the breaking length is output.

The surface analysis program according to one aspect of the present disclosure is a probe that is the distance between the probe and the sample surface, and the step of acquiring a force curve based on the measurement of the sample surface by a scanning probe microscope equipped with a probe. The step of calculating the differential curve by first-order differentiating the force curve according to the inter-surface distance, and the distance from the sample surface to the farthest peak based on the differential curve, the breaking length of the organic material forming the sample surface. The computer is made to execute the step of calculating as and the step of outputting the breaking length.

In such an aspect, by first-order differentiating the force curve based on the measurement by the scanning probe microscope according to the distance between the probe and the surface, a differential curve showing a point (peak) where the force fluctuates momentarily is obtained. Be done. Then, based on this differential curve, the distance from the surface to the farthest peak is obtained as the breaking length of the organic material forming the surface of the sample. Since the breaking length showing the characteristics of the organic material is obtained by this series of treatments, the organic material formed on the surface of the sample can be analyzed in more detail.

According to one aspect of the present disclosure, the organic material formed on the surface of the sample can be analyzed in more detail.

It is a figure which shows an example of the hardware composition of the computer which comprises the surface analysis system which concerns on embodiment. It is a figure which shows an example of the functional structure of the surface analysis system which concerns on embodiment. It is a flowchart which shows an example of the operation of the surface analysis system which concerns on embodiment. It is a schematic diagram of the measurement part of an atomic force microscope. Voltage - shows an example of conversion from operating quantity curve _(F v -Z curve) to force curve _(F N -D curve). It is a figure which shows an example of the relationship between the liquid used in the measurement of a sample surface, and a force curve. It is a figure which shows an example of the force curve and the corresponding differential curve. It is a figure which shows another example of a force curve and a corresponding derivative curve. It is a figure which shows an example of the 1st analysis data including the breaking length. It is a flowchart which shows an example of the further operation of the surface analysis system which concerns on embodiment. It is a figure which shows an example of the 2nd analysis data including the breaking length. It is a figure which shows the image of the silica filler obtained by the scanning electron microscope. It is a figure which shows the amplitude image of the silica filler obtained by the dynamic mode measurement of an atomic force microscope. It is a figure which shows the phase image of the silica filler obtained by the dynamic mode measurement of an atomic force microscope. It is a figure which shows an example of the range of an observation point schematically. It is a figure which shows the force curve of the unprocessed Phila. It is a figure which shows the distribution of the force in the untreated filler. It is a figure which shows the force curve of the epoxy-treated Phila. It is a figure which shows the distribution of the force in the epoxy-treated filler. It is a figure which shows the force curve of the phenyl-treated Fila. It is a figure which shows the distribution of the force in the phenyl-treated filler. It is a figure which shows an example of the 2nd analysis data using the breaking length.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

[Surface analysis system configuration]
The surface analysis system 10 according to the embodiment is a computer system that analyzes the surface of a sample that may contain an organic material (this is also referred to as a "sample surface" in the present disclosure). An organic material is a material composed of an organic compound. A sample is a substance whose surface is to be analyzed. In one example, the "sample containing an organic material" is a substance whose surface is formed by the organic material, for example, a substance in which a layer of the organic material is formed on the surface of a powder such as filler. A powder is an aggregate of a large number of fine solid particles. Analysis of the sample surface is a process for clarifying some characteristics of the sample surface.

The surface analysis system 10 executes analysis using data obtained from a scanning probe microscope. A scanning probe microscope refers to a microscope that observes the physical properties (for example, shape, properties, state, etc.) of a substance by moving the surface of the substance by tracing it with a cantilever probe. An atomic force microscope can be mentioned as an example of the scanning probe microscope, but the type of the scanning probe microscope used together with the surface analysis system 10 is not limited to the example. In this embodiment, an atomic force microscope (AFM) is shown as an example of a scanning probe microscope. The AFM can support various measurement methods such as contact mode, dynamic mode, and force mode. In the force mode, various physical properties such as elastic modulus, maximum breaking force (adhesive force), and surface position can be obtained.

The surface analysis system 10 is composed of one or more computers. When a plurality of computers are used, one surface analysis system 10 is logically constructed by connecting these computers via a communication network such as the Internet or an intranet.

FIG. 1 is a diagram showing an example of a general hardware configuration of a computer 100 constituting the surface analysis system 10. The computer 100 includes a processor (for example, a CPU) 101 for executing an operating system, an application program, and the like, a main storage unit 102 composed of a ROM and a RAM, an auxiliary storage unit 103 composed of a hard disk, a flash memory, and the like. It includes a communication control unit 104 composed of a network card or a wireless communication module, an input device 105 such as a keyboard and a mouse, and an output device 106 such as a monitor.

Each functional element of the surface analysis system 10 is realized by reading a predetermined program on the processor 101 or the main storage unit 102 and causing the processor 101 to execute the program. The processor 101 operates the communication control unit 104, the input device 105, or the output device 106 according to the program, and reads and writes data in the main storage unit 102 or the auxiliary storage unit 103. The data or database required for processing is stored in the main storage unit 102 or the auxiliary storage unit 103.

FIG. 2 is a diagram showing an example of the functional configuration of the surface analysis system 10. In one example, the surface analysis system 10 includes a first analysis unit 11 and a second analysis unit 12 as functional elements. The first analysis unit 11 is a functional element for obtaining the breaking length of the organic material forming the sample surface by processing the data obtained by AFM (this is referred to as “input data” in the present disclosure). In the present disclosure, the breaking length refers to the distance from the sample surface to the probe when the organic material adhering to the probe of a scanning probe microscope (for example, AFM) is separated from the probe due to attractive force. Say. The breaking length is an example of the physical properties of the sample surface or organic material. The calculation of fracture length is at least part of the analysis of the sample surface. The first analysis unit 11 includes an acquisition unit 111, a calculation unit 112, and a storage unit 113. The acquisition unit 111 is a functional element for acquiring input data. The calculation unit 112 is a functional element that calculates the breaking length from the input data. The storage unit 113 is a functional element that stores the first analysis data including the breaking length in the database 20. The second analysis unit 12 is a functional element that executes further analysis on the sample surface using the first analysis data and outputs the second analysis data showing the analysis result.

The method of constructing the surface analysis system 10 is not limited. When the surface analysis system 10 is composed of a plurality of computers, it may be arbitrarily determined which processor executes which functional element. In any case, the surface analysis system 10 including at least one processor functions as the first analysis unit 11 (acquisition unit 111, calculation unit 112, and storage unit 113) and the second analysis unit 12. The surface analysis system 10 may be incorporated in the AFM or may be a computer system independent of the AFM.

The surface analysis system 10 can access the database 20. The database 20 is a device (storage unit) that stores analysis data non-temporarily. In one example, the database 20 is a relational database, but the configuration of the database 20 is not limited to this, and may be designed and constructed according to an arbitrary policy. The database 20 may be a component of the surface analysis system 10 or may be constructed in a computer system different from the surface analysis system 10. In one example, the surface analysis system 10 connects to the database 20 via a communication network. The configuration of the communication network is not limited in any way, and for example, the communication network may be constructed using the Internet, an intranet, or the like.

[Operation of surface analysis system]
The operation of the surface analysis system 10 and the surface analysis method according to the present embodiment will be described with reference to FIG. 3 and other drawings. FIG. 3 is a flowchart showing an example of the operation of the surface analysis system 10 as a processing flow S1. The processing flow S1 indicates a processing for analyzing at least one observation point on the sample surface. The trigger of the processing flow S1 is not limited. For example, the processing flow S1 may be executed in response to a user operation of the surface analysis system 10. Alternatively, the processing flow S1 may be automatically executed in response to processing by the AFM or another device without any user operation.

In step S11, the acquisition unit 111 acquires the input data for one observation point. The input data is data generated by the AFM that measures the sample surface and used to analyze the sample surface. The method of acquiring the input data is not limited. For example, the acquisition unit 111 may acquire input data directly from the AFM, or may read data stored in a predetermined storage unit (for example, a memory, a database, etc.) from the AFM as input data from the storage unit. Good. The input data may include other data such as measurement position information, maximum breaking force, surface position, etc., in addition to the data used to calculate the breaking length. At least some of such other data can be additional physical properties obtained in addition to the breaking length. The maximum breaking force is the maximum value of the force applied to the probe that tries to move away from the sample surface, and is also called the adhesion force. The surface position can be indicated by the distance from a given reference plane to the sample surface in the Z direction (vertical direction). Both the maximum breaking force and the surface position are examples of the additional physical properties obtained in addition to the breaking length.

In step S12, it is determined whether or not the calculation unit 112 has acquired a sufficient amount of input data. In the measurement of the sample surface, for some reason, the applied voltage reaches the limit value before the probe reaches the surface, the sample surface is located outside the scanning range, or the organic material does not leave the probe. Therefore, it is possible that a sufficient amount of input data cannot be obtained. Therefore, the calculation unit 112 determines whether or not a sufficient amount of input data has been acquired for analysis.

In one example, the calculation unit 112 determines that the amount of input data is not sufficient when the number of data is less than or equal to a given threshold value, and the amount of input data is sufficient when the number of data is greater than the threshold value. Is determined to be. The threshold may be set by any policy. For example, the threshold value may be 50 as long as 1024 data can be acquired along the Z direction for one observation point.

Alternatively, the calculation unit 112 determines that the amount of input data is not sufficient if the size of the data file is equal to or less than a given threshold value (for example, 1/5 or less of the average size), and if the size is larger than the threshold value. May determine that the amount of input data is sufficient.

Alternatively, the calculation unit 112 has a section farthest from the sample surface on the approach curve (for example, a section indicated by 10 data corresponding to the corresponding portion) and a section farthest from the sample surface on the release curve (for example, corresponding). The validity of the input data may be determined depending on whether or not the interval (the section indicated by the 10 data corresponding to the location) overlaps. If there is no such overlap, it is highly probable that the organic material did not separate from the probe until the end. The calculation unit 112 determines that the input data is sufficient when there is overlap, and determines that the input data is insufficient when there is no overlap. Here, the approach curve indicates the force measured when the probe approaches the sample surface, and the release curve indicates the force measured when the probe in contact with the sample surface moves away from the sample surface.

When a sufficient amount of input data has been acquired (YES in step S12), the process proceeds to step S13. On the other hand, if a sufficient amount of input data is not acquired (NO in step S12), the surface analysis system 10 determines that the input data is invalid and ends the process for the current measurement point. .. In this case, the surface analysis system 10 does not execute the processes of steps S13 to S17 described later.

In step S13, calculation unit 112, the voltage is represented by at least a portion of the input data - converting operation amount curve (F v _-Z curve) the force curve.

The force curve indicates the relationship between the probe-surface distance D (unit: nm (nanometer)) and the force F _N (unit: nN (nanonewton)) acting on the AFM probe (cantilever). a curve _(F N -D curve). FIG. 4 is a schematic view of an AFM measuring unit shown to explain the probe-surface distance D. This figure shows a probe 32 provided at the end of a cantilever 31, a sample 40 placed on a stage 33, and a piezoelectric element (piezo element) for moving the sample 40 in a three-dimensional direction with high accuracy. 34 and is shown. As shown in the figure, the probe-surface distance D refers to the distance between the tip of the probe 32 and the sample surface 41.

Voltage - The production amount curve (F v _-Z curve), and operation of the piezoelectric element of the scanning probe microscope (for example, AFM) Z (unit nm (nanometers)), of the scanning probe microscope detector It is a curve which shows the relationship with voltage F _{v (unit is V (volt)).}

Calculating unit 112 converts the _F v -Z curve force curve _(F N -D curve). Assuming that the amount of deflection of the cantilever is the amount of deflection x of the spring (unit: nm), the calculation unit 112 converts the operating amount Z of the piezoelectric element into the distance D between the probe and the surface according to the equation D = Zx. The spring deflection amount x is _{obtained by the equation x = (detector voltage Fv} ) / (light lever sensitivity). The unit of light lever sensitivity is nm / V. The force F _N is obtained by the product of the spring constant k of the cantilever and the amount of spring deflection x, and therefore F _N = kx. Figure 5 is a voltage - is a diagram showing an example of conversion from operating quantity curve _(F v -Z curve) to force curve _(F N -D curve). In the force curve, _{the region of F N} > 0 indicates that a repulsive force acts on the probe, and the region of F _N <0 indicates that an attractive force acts on the probe. In the example of FIG. 5, the maximum value of the attractive force in the vicinity of the probe-surface distance D = 0 corresponds to the maximum breaking force.

As a method for clearly detecting the maximum breaking force (adhesive force), the sample surface is measured by bringing the probe into contact with the sample surface in an aqueous solution. When the sample surface is measured in pure water instead of an aqueous solution, a repulsive force due to electrostatic repulsion is generated, and the breaking force is canceled by the repulsive force and cannot be confirmed. When the sample surface is measured in an aqueous solution, its electrostatic repulsion is prevented or suppressed, so that the repulsive force caused by the electrostatic repulsion is also prevented or suppressed. As a result, it is possible to obtain a force curve in which the maximum breaking force clearly appears. In one example, an aqueous solution that is difficult to evaporate, does not dissolve the organic material, and does not swell the organic material is selected. Examples of the aqueous solution used for measuring the sample surface with a scanning probe microscope such as AFM include an aqueous solution of sodium chloride (NaCl), an aqueous solution of sodium sulfate (Na ₂ SO ₄ ), and an aqueous solution of potassium chloride (KCl). Not limited to. The ionic strength of the aqueous solution is preferably 0.01 (mol / L) or more. For example, the ionic strength of an aqueous NaCl solution having a molar concentration of 10 mM (mmol / L) is 0.01 (mol / L).

FIG. 6 is a diagram showing an example of the relationship between the liquid used for measuring the sample surface and the force curve. In this example, the sample is niobium, but of course the type of sample is not limited to this. The graph (a) of FIG. 6 shows the force curve obtained when the sample surface is measured in pure water. The graph (b) of FIG. 6 shows the force curve obtained when the sample surface is measured in an aqueous NaCl solution. In both graphs, the gray line (approach curve) indicates the force measured as the probe approaches the sample surface, and the black line (release curve) indicates the probe that was in contact with the sample surface. Shows the force measured as it moves away from the sample surface. As shown in FIG. 6, the maximum breaking force can be clearly detected by using an aqueous solution.

In step S14, the calculation unit 112 calculates the differential curve by differentiating the force curve. Specifically, the calculation unit 112 calculates the differential curve by first-order differentiation (that is, dF _N / dD) of the force curve by the probe-surface distance D. 7 and 8 are both diagrams showing an example of a force curve and a corresponding differential curve. In these figures, the upper graph shows the force curve and the lower graph shows the differential curve. The vertical axis of the differential curve _{shows dF N} / dD, and the horizontal axis shows the probe-surface distance D. In each graph, the gray line (approach curve) is the force measured as the probe approaches the sample surface, and the black line (release curve) is the probe that was in contact with the sample surface. With respect to the force measured as the sample moves away from the sample surface.

In step S15, the calculation unit 112 determines the peak threshold value applied to the differential curve. In the present disclosure, the peak means the maximum value in the needle-shaped portion where the differential value protrudes from the other portions, and corresponds to the portion where the force applied to the probe (cantilever) fluctuates significantly momentarily. The peak threshold is a value set to identify a peak on the differential curve. The method of setting the peak threshold value is not limited. In one example, the calculation unit 112 may set the peak threshold value based on the signal-to-noise ratio (S / N) of the differential curve, and may set the peak threshold value to 5 dB (decibel), for example. The calculation unit 112 may calculate the noise statistical value (for example, mean square error) in the section of the differential curve where the organic material is not attached as the noise level which is the basis of S / N.

In step S16, the calculation unit 112 calculates the distance from the sample surface to the farthest peak as the breaking length of the organic material based on the differential curve. The "farthest peak" means the peak farthest from the sample surface. The calculation unit 112 identifies each of one or more needle-shaped portions having a value higher than the peak threshold value in the differential curve as a peak. Breakage, which is a phenomenon in which the organic material separates from the probe, may occur multiple times, and in response to this, the force applied to the probe may fluctuate significantly momentarily at each breakage. Therefore, there can be multiple peaks. Therefore, the calculation unit 112 identifies the peak farthest from the sample surface (the portion where D = 0 in the graph of the differential curve) as the farthest peak. Then, the calculation unit 112 calculates the distance from the sample surface to the farthest peak as the breaking length of the organic material. The distance L in FIGS. 7 and 8 indicates the breaking length thereof. By obtaining the distance from the sample surface to the farthest peak as the breaking length, the existence of an organic material having a length longer than the breaking length can be known.

By finding the differential curve, it is possible to capture the timing at which the force applied to the probe fluctuates significantly momentarily as a peak. Since this variation indicates fracture, the fracture length can be accurately determined based on the position of the peak on the differential curve. In addition, as is clear from FIG. 8, _{the long-period distortion of the baseline of the force curve (the line near the force NF} of 0) due to the interference of light can be eliminated by the differential curve.

In step S17, the storage unit 113 stores the first analysis data including at least the breaking length in the database 20. The first analysis data may include at least a part of the input data as an additional physical characteristic quantity, or may not include such an additional physical characteristic quantity. FIG. 9 is a diagram showing an example of the first analysis data. In this example, the record of analytical data for one observation point includes the observation point ID, filename, X position, Y position, surface position, breaking length, and maximum breaking force. The observation point ID is an identifier that uniquely identifies each observation point. The file name is the name of the electronic file in which the input data is written. The X position and the Y position indicate the positions of the observation points in the X and Y directions set based on the surface (XY plane) of the AFM stage. It can be said that the individual records shown in FIG. 9 show the combination of the breaking length and the additional physical properties.

As shown in step S18, the surface analysis system 10 performs processing on all of at least one observation point on the sample surface. If there are unprocessed observation points (NO in step S18), the processing of steps S11 to S17 is executed for one of the remaining observation points. When the surface analysis system 10 has processed all the observation points (YES in step S18), the processing flow S1 ends. As a result, as shown in FIG. 9, the database 20 stores the first analysis data for one or more observation points processed this time. The surface analysis system 10 may output a plurality of break lengths corresponding to a plurality of measurement points, or may calculate and output a single break length corresponding to a single measurement point.

In one example, the surface analysis system 10 may perform further processing (eg, further analysis) using the analysis data. FIG. 10 is a flowchart showing an example of the further processing as a processing flow S2. The surface analysis method according to the present embodiment may or may not include this processing flow S2. The trigger of the processing flow S2 is not limited. In one example, the processing flow S2 may be automatically executed following the processing flow S1. In another example, the processing flow S2 may be executed in response to a user operation of the surface analysis system 10. Alternatively, the processing flow S2 may be automatically executed in response to processing by the AFM or another device without any user operation.

In step S21, the second analysis unit 12 acquires the first analysis data to be processed from the database 20. In step S22, the second analysis unit 12 executes further processing using the first analysis data. In one example, the second analysis unit 12 performs further analysis with reference to at least the break length at one or more observation points. The second analysis unit 12 may perform analysis based on the combination of the breaking length and the additional physical properties. In step S23, the second analysis unit 12 outputs the second analysis data indicating the result of the processing (for example, analysis). The output method of the second analysis data is not limited. For example, the second analysis unit 12 may output the second analysis data on a monitor, store it in an arbitrary storage unit such as a database 20, or transmit it to another computer or device. You may print it. The processing by the second analysis unit 12 is not limited, and the data structure and representation format of the second analysis data are not limited accordingly.

In the following, the surface analysis system 10 and the surface analysis method according to the embodiment will be further described with reference to further drawings.

FIG. 11 is a diagram showing an example of the second analysis data including the breaking length, and more specifically, shows the second analysis data 200 showing the distribution of the amount of physical properties in a specific range on the sample surface. The second analysis data 200 includes a map 201 showing the distribution of surface positions, a map 202 showing the distribution of the maximum breaking force (adhesive force), and a map 203 showing the distribution of the breaking length. By visualizing the breaking length as in the second analysis data 200, the user of the surface analysis system 10 can visually grasp the state of the organic material on the sample surface. The second analysis data 200 is an example of the result of the analysis based on the combination of the breaking length and the additional physical properties.

The present inventors have found that the presence or type of an organic material on the sample surface can be determined by calculating the distribution of breaking length. This discrimination is impossible or very difficult just by looking at the image obtained from the microscope by the conventional method. FIG. 12 is a diagram showing images of three types of silica fillers obtained by a scanning electron microscope (SEM). Silica filler is an example of powder. The three types of silica fillers are a silica filler that does not contain an organic material (untreated filler), a silica filler that uses 3-glycidoxypropyltrimethoxysilane as an organic material (epoxy-treated filler), and an organic material. It is a silica filler (phenyl-treated filler) using N-phenyl-3-aminopropyltrimethoxysilane. FIG. 13 is a diagram showing an amplitude image obtained by dynamic mode measurement of AFM, and shows four samples for each of the above three types of silica fillers. FIG. 14 is a diagram showing a phase image obtained by dynamic mode measurement of AFM, and shows four samples for each of the above three types of silica fillers. As can be seen from FIGS. 12 to 14, it is impossible or very difficult to distinguish the three types of silica fillers using any of the images.

For example, the force curve is a trigger to distinguish the above three types of silica fillers. An example of expressing the force curve will be described with reference to FIGS. 15 to 22. FIG. 15 is a diagram schematically showing an example of the range of observation points. FIG. 16 is a diagram showing a force curve at a typical observation point of unprocessed Fira. FIG. 17 is a diagram showing the force distribution in the untreated filler and corresponds to FIG. FIG. 18 is a diagram showing a force curve at a typical observation point of an epoxy-treated filler. FIG. 19 is a diagram showing the force distribution in the epoxy-treated filler, which corresponds to FIG. FIG. 20 is a diagram showing a force curve at a typical observation point of a phenyl-treated filler. FIG. 21 is a diagram showing the distribution of force in the phenyl-treated filler, which corresponds to FIG. 20.

The measurement environment was as follows. A scanning probe microscope SPM8100 manufactured by Shimadzu Corporation was used as a microscope, and SPM9700 manufactured by Shimadzu Corporation was used as software. Each silica filler was measured in force mode. TR800PSA-1 manufactured by Olympus Corporation was used as the cantilever. The spring constant of this cantilever was 150 pN / nm. The light lever sensitivity was 20 nm / V. The scanning range in the Z direction was 1 um (micrometer), and the scanning speed was 1 Hz. The maximum pushing force of the cantilever was + 0.2 V in terms of the detector voltage. The measurement of the sample surface was carried out in an aqueous NaCl solution having a molar concentration of 10 mM (mmol / L).

FIG. 15 shows the range 51 of the observation points set on the silica filler 50 together with the coordinate system. The XY plane was set along the surface of the AFM stage and the Z axis was set along the vertical direction. The average particle size of the silica filler 50 was 500 nm. The actual size of range 51 was 200 nm × 25 nm, which corresponded to 64 × 8 observation points. 15 to 21 each show a graph or map at a specific Y position. 16 and 18 and 20 all show force curves at seven observation points (X = −75 nm, -50 nm, -25 nm, 0 nm, 25 nm, 50 nm, 75 nm) at a particular Y position. In each graph, the gray line (approach curve) indicates the force measured as the probe approaches the sample surface, and the black line (release curve) indicates the probe that was in contact with the sample surface. Shows the force measured as it moves away from the sample surface. 17, 19 and 21 all show the distribution of forces in the XZ plane at a particular Y position, and the arrows on the map indicate the above seven observation points.

In FIG. 17, the bright portion 210 shows repulsive force, which corresponds to the untreated filler. The color-changing boundary 211 corresponds to the surface of the untreated filler. The breaking length could not be recognized from this map.

In FIG. 19, the bright portion 220 shows repulsive force, which corresponds to the epoxy treated filler. The color-changing boundary 221 corresponds to the surface of the epoxy-treated filler. Further, the color-changing boundary 222 corresponds to the point in time when the organic material is completely separated from the probe. Therefore, the distance from the boundary 221 to the boundary 222 in the Z-axis direction corresponds to the breaking length.

FIG. 21 is the same as FIG. That is, in FIG. 21, the bright portion 230 exhibits repulsive force, which corresponds to the phenyl treated filler. The color-changing boundary 231 corresponds to the surface of the phenyl-treated filler. Further, the color-changing boundary 232 corresponds to the point in time when the organic material is completely separated from the probe. Therefore, the distance from the boundary 231 to the boundary 232 in the Z-axis direction corresponds to the breaking length.

As shown in FIGS. 16 to 21, the physical characteristics of the sample surface can be confirmed to some extent by the force curve and the map based on the force curve. Since the breaking length can be calculated by using the surface analysis system 10, its physical properties can be confirmed in more detail. FIG. 22 is a diagram showing an example of the second analysis data using the calculated breaking length, and more specifically, is a graph showing the relationship between the breaking length and the maximum breaking force for the above three types of silica fillers. is there. This graph is an example of the results of analysis based on the combination of breaking length and additional physical properties. Each point in the graph corresponds to each observation point. Point cloud 241 shows the results for untreated fillers, point group 242 shows the results for epoxy treated fillers, and point group 243 shows the results for phenyl treated fillers. As can be seen from this graph, the point cloud of each silica filler can be more clearly distinguished by calculating the breaking length, so that each silica filler can be discriminated.

[program]
The surface analysis program for making the computer system function as the surface analysis system 10 is for making the computer system function as the first analysis unit 11 (acquisition unit 111, calculation unit 112, and storage unit 113) and the second analysis unit 12. Includes the program code of. The programming language for creating the surface analysis program is not limited, and the programming language may be, for example, Python, Java®, or C ++. The surface analysis program may be provided after being non-temporarily recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. Alternatively, the surface analysis program may be provided via a communication network as a data signal superimposed on a carrier wave. The provided surface analysis program is stored in, for example, the auxiliary storage unit 103. Each of the above functional elements is realized by the processor 101 reading the surface analysis program from the auxiliary storage unit 103 and executing the program.

[effect]
As described above, the surface analysis method according to one aspect of the present disclosure is between the step of acquiring a force curve based on the measurement of the sample surface by a scanning probe microscope equipped with a probe and the probe and the sample surface. The sample surface is formed by the step of calculating the differential curve by first-order differentiating the force curve by the distance between the probe and the surface, and the distance from the sample surface to the farthest peak based on the differential curve. It includes a step of calculating the breaking length of the organic material to be used and a step of outputting the breaking length.

In the surface analysis method according to the other aspect, the step of acquiring the force curve acquires a voltage-operating amount curve showing the relationship between the operating amount of the piezoelectric element of the scanning probe microscope and the voltage of the detector of the scanning probe microscope. A step of converting a voltage-working amount curve into a force curve may be included. If the voltage-operating amount curve is used as it is, an error will occur in the breaking length by the amount of deflection of the cantilever of the scanning probe microscope (for example, the breaking length will be overestimated by the amount of deflection). By converting the voltage-working amount curve into a force curve, the breaking length can be calculated more accurately.

In the surface analysis method relating to the other aspect, the step of converting the voltage-operating amount curve into the force curve is the step of calculating the probe-surface distance by reducing the spring deflection amount of the cantilever having the probe from the operating amount. And the step of calculating the force acting on the probe by multiplying the spring constant of the cantilever by the distance between the probe and the surface may be included. By calculating the distance between the probe and the surface and the force in this way, the force curve can be obtained by a simple calculation.

In the surface analysis method relating to other aspects, a step of acquiring a force curve at each of a plurality of measurement points on the sample surface, a step of calculating a break length for each of the plurality of force curves, and a step of outputting a plurality of break lengths. It may further include steps to be performed. By obtaining the breaking lengths at a plurality of measurement points, it is possible to obtain further information on the breaking lengths such as the distribution of the breaking lengths, statistical values, and the like.

In the surface analysis method relating to other aspects, the step of outputting a plurality of breaking lengths may include a step of outputting the distribution of breaking lengths on the sample surface. In this case, information on the breaking length can be presented to the user in an easy-to-understand manner.

In the surface analysis method relating to other aspects, the step of outputting a plurality of break lengths may include a step of storing a plurality of break lengths in the database. In this case, information about the breaking length can be saved for various subsequent processes.

The surface analysis method according to the other aspect includes a step of obtaining an additional physical property amount based on the measurement of the sample surface by a scanning probe microscope, a step of performing an analysis based on a combination of the breaking length and the additional physical property amount, and a step of performing an analysis. It may further include a step of outputting the result of the analysis. In this case, the organic material formed on the surface of the sample can be analyzed in more detail.

In the surface analysis method according to the other aspect, the measurement of the sample surface may include bringing the probe into contact with the sample surface in an aqueous solution. When the sample surface is measured in an aqueous solution, electrostatic repulsion is prevented or suppressed, so that the repulsive force caused by electrostatic repulsion is also prevented or suppressed. As a result, it is possible to obtain a force curve in which the maximum breaking force clearly appears.

In the surface analysis method relating to other aspects, the sample surface may be the surface of the powder. In this case, the organic material formed on the surface of the powder can be analyzed in more detail.

[Modification example]
The above description has been made in detail based on the embodiments in the present disclosure. However, the present disclosure is not limited to the above embodiment. The present disclosure can be modified in various ways without departing from its gist.

In the above embodiment, the surface analysis system 10 converts the voltage-working amount curve into a force curve, but this conversion process is not essential. For example, the surface analysis system may acquire force curve data calculated by a scanning probe microscope or other computer system.

In the above embodiment, the surface analysis system 10 uses the peak threshold value to identify the farthest peak, but the method for identifying the farthest peak is not limited to this. The surface analysis system may calculate the breaking length by identifying the farthest peak using other techniques.

Neither the configuration of the surface analysis system 10 nor the system configuration around it is limited to the above embodiment. The second analysis unit 12 is not an essential component of the surface analysis system, and for example, a computer system other than the surface analysis system may have a function corresponding to the second analysis unit 12. The process of storing the fracture length in the database is also not essential, for example, the surface analysis system may display the fracture length on a monitor, send it to another computer or device, or print it. Good.

In the present disclosure, the expression "at least one processor executes the first process, executes the second process, ... executes the nth process", or the expression corresponding thereto is the first. The concept including the case where the execution subject (that is, the processor) of n processes from the first process to the nth process changes in the middle is shown. That is, this expression shows a concept including both a case where all n processes are executed by the same processor and a case where the processor changes according to an arbitrary policy in n processes.

The processing procedure of the method executed by at least one processor is not limited to the example in the above embodiment. For example, some of the steps (processes) described above may be omitted, or each step may be executed in a different order. Further, any two or more steps among the above-mentioned steps may be combined, or a part of the steps may be modified or deleted. Alternatively, other steps may be performed in addition to each of the above steps.

When comparing the magnitude relations of two numbers in a computer system or computer, either of the two criteria "greater than or equal to" and "greater than" may be used, and the two criteria "less than or equal to" and "less than" Either of the criteria may be used. The selection of such criteria does not change the technical significance of the process of comparing the magnitude relations of two numbers.

10 ... surface analysis system, 11 ... first analysis unit, 12 ... second analysis unit, 20 ... database, 111 ... acquisition unit, 112 ... calculation unit, 113 ... storage unit, 31 ... cantilever, 32 ... probe, 40 ... Sample, 41 ... Sample surface.

Claims

Steps to obtain a force curve based on the measurement of the sample surface with a scanning probe microscope equipped with a probe,
A step of calculating a differential curve by first-order differentiating the force curve according to the distance between the probe and the surface, which is the distance between the probe and the sample surface.
Based on the differential curve, the step of calculating the distance from the sample surface to the farthest peak as the breaking length of the organic material forming the sample surface, and
A surface analysis method including a step of outputting the breaking length.
The step of acquiring the force curve is
A step of acquiring a voltage-operating amount curve showing the relationship between the operating amount of the piezoelectric element of the scanning probe microscope and the voltage of the detector of the scanning probe microscope, and
Including the step of converting the voltage-working amount curve into the force curve.
The surface analysis method according to claim 1.
The step of converting the voltage-working amount curve into the force curve is
A step of calculating the distance between the probe and the surface by reducing the amount of spring deflection of the cantilever having the probe from the operating amount, and
The step includes calculating the force acting on the probe by multiplying the spring constant of the cantilever by the distance between the probe and the surface.
The surface analysis method according to claim 2.
The step of acquiring the force curve at each of the plurality of measurement points on the sample surface, and
A step of calculating the breaking length for each of the plurality of force curves, and
The surface analysis method according to any one of claims 1 to 3, further comprising a plurality of steps of outputting the breaking length.
The step of outputting the plurality of breaking lengths includes a step of outputting the distribution of the breaking lengths on the sample surface.
The surface analysis method according to claim 4.
The step of outputting the plurality of break lengths includes a step of storing the plurality of break lengths in the database.
The surface analysis method according to claim 4 or 5.
The step of obtaining additional physical properties based on the measurement of the sample surface with the scanning probe microscope, and
A step of performing an analysis based on the combination of the breaking length and the additional physical properties,
The surface analysis method according to any one of claims 1 to 6, further comprising a step of outputting the result of the analysis.
Measurement of the sample surface comprises contacting the probe with the sample surface in aqueous solution.
The surface analysis method according to any one of claims 1 to 7.
The surface of the sample is the surface of the powder.
The surface analysis method according to any one of claims 1 to 8.
With at least one processor
The at least one processor
Obtain a force curve based on the measurement of the sample surface with a scanning probe microscope equipped with a probe.
A differential curve is calculated by first-order differentiating the force curve according to the distance between the probe and the surface, which is the distance between the probe and the sample surface.
Based on the differential curve, the distance from the sample surface to the farthest peak is calculated as the breaking length of the organic material forming the sample surface.
Output the breaking length,
Surface analysis system.
Steps to obtain a force curve based on the measurement of the sample surface with a scanning probe microscope equipped with a probe,
A step of calculating a differential curve by first-order differentiating the force curve according to the distance between the probe and the surface, which is the distance between the probe and the sample surface.
Based on the differential curve, the step of calculating the distance from the sample surface to the farthest peak as the breaking length of the organic material forming the sample surface, and
A surface analysis program that causes a computer to perform the steps of outputting the breaking length.