Inspection method for diamond machining tools and performance evaluation method for diamond machining tools

Abstract

To provide an inspection method for a diamond tool for machining using diamond abrasive grains that enables performance to be evaluated without actually performing the machining process.SOLUTION: The inspection method for a diamond tool for machining includes: a preparation step S1 for preparing a diamond tool with diamond abrasive grains electrodeposited on its surface; an abrasive grain information acquisition step S2 for acquiring, for each abrasive grain, the position of the abrasive grain recognised as a diamond abrasive grain by observing the surface; a spectral measurement step S3 for performing a Raman spectral measurement on the recognised abrasive grains; a calculation step S4 for calculating, on the basis of the results of the Raman spectral measurement, the proportion of abrasive grains whose Raman scattering light has the main peak of the peak of diamond crystal alone, the proportion of abrasive grains whose main peak is a combined peak of diamond crystal and amorphous carbon, and the proportion of abrasive grains showing no peak and electrically worn metal, with respect to the total number of abrasive grains measured; and a determination step S5 for determining the performance of the diamond tool on the basis of the calculated proportions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting a diamond tool for machining and a method for evaluating the performance of a diamond tool for machining. [Background technology]

[0002] For example, in grinding, diamond abrasive grains are used as fixed abrasive grains fixed to a substrate or as free abrasive grains dispersed in a liquid.

[0003] Fixed abrasive wire grinding tools, which have diamond abrasive grains fixed to the outer surface of a fine wire, and grinding wheels, which have diamond abrasive grains fixed to the surface of a disk-shaped disc, are known as fixed abrasive grinding tools and are used in a variety of processing fields.

[0004] For example, when manufacturing various semiconductor devices such as solar cells, semiconductors, and magnetic materials, a cylindrical raw material ingot made of single crystal, polycrystalline, or amorphous silicon, crystal, quartz, glass, sapphire, silicon carbide, or the like is cut into thin plates (wafers) of a predetermined thickness by a slicing process. Fixed abrasive wire is considered suitable for cutting such highly brittle materials with high precision and at low cost.

[0005] In order to obtain uniform sharpness in a fixed-abrasive grinding tool, it is desirable that there be no variation in the characteristics of the diamond abrasive grains fixed to the substrate.

[0006] For example, when using a fixed abrasive wire, a wire as long as 5 km is set in a wire saw device and moved back and forth over a length range of about 2 to 3 km, while gradually winding it up to change its position of use. Therefore, it is necessary for the wire to have a uniform sharpness along its entire length, and since there are well over 100,000 diamond abrasive grains fixed to it, it is even more desirable that there be no variation in their characteristics.

[0007] Furthermore, since the abrasive grains attached to the fixed abrasive wire are only one or two layers, if the abrasive grains break and fall off, the sharpness of the affected area immediately decreases. In particular, when a thin and fragile fine wire is used as the substrate, the abrasive grains wear down and fall off, causing scratches in the substrate and easily leading to wire breakage.

[0008] Therefore, when cutting such wires into products, it is necessary to thoroughly evaluate the state of diamond electrodeposition and the state of diamond falling off and exposure after cutting.

[0009] In addition, the Raman spectrum shows a peak of the diamond crystal alone at approximately 1333 (cm -1 ) can be obtained, making it a suitable evaluation method for observing diamond abrasive grains used in cutting and grinding (Patent Document 1). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2019-025610 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the performance of wire saws using fixed abrasive wires and grinding wheels with diamond abrasive grains attached cannot be judged unless they are actually used for machining such as cutting or grinding.

[0012] Furthermore, even when the wire or grinding wheel surface is observed with an optical microscope or electron microscope to evaluate the wire or grinding wheel after cutting or grinding, it is difficult to determine the amount of remaining diamond, except in cases where most of the electrodeposited diamond has fallen off, making it difficult to evaluate the quality of the electrodeposited diamond.

[0013] The present invention has been made against the background of the above circumstances, and its purpose is to provide an inspection method for diamond tools for machining using diamond abrasive grains, which can evaluate performance without actually performing machining. Another object of the present invention is to provide a method for evaluating the performance of a diamond tool for machining, which is capable of evaluating with high accuracy the degree of change in performance due to machining when actual machining is performed. [Means for solving the problem]

[0014] The present invention has been made to achieve the above-mentioned object, and provides an inspection method for diamond tools for machining, comprising the following steps: a preparation step of preparing a diamond tool having diamond abrasive grains electrodeposited on the surface of a substrate; an abrasive grain information acquisition step of observing the surface and acquiring the positions of the abrasive grains recognized as the diamond abrasive grains for each of the abrasive grains; a spectroscopic measurement step of performing Raman spectroscopy on the abrasive grains recognized as the diamond abrasive grains; a calculation step of calculating, based on the results of the Raman spectroscopy measurement, the proportion of abrasive grains whose Raman scattered light has a main peak of diamond crystal alone, the proportion of abrasive grains whose main peak is a composite peak of diamond crystal and amorphous carbon, and the proportion of abrasive grains whose Raman scattered light has no peak, relative to the total number of the measured abrasive grains; and a determination step of determining the performance of the diamond tool based on the calculated proportions.

[0015] According to this inspection method, the surface of a diamond tool for machining is observed, and Raman spectroscopy is performed on abrasive grains that are recognized as diamond abrasive grains. The performance of the diamond tool is determined based on the proportion of abrasive grains whose surface layer is determined to be diamond crystals, abrasive grains whose surface layer is determined to contain amorphous carbon, and abrasive grains whose surface layer is determined to be electrodeposited metal, relative to the number of measurements.

[0016] Abrasive grains with a diamond crystal surface contribute to machining, abrasive grains with an amorphous carbon surface have diamond crystals that have been partially carbonized due to reactions caused by processing heat, etc., and contain amorphous carbon, making the diamond crystals more susceptible to deterioration and easier to fall off, and abrasive grains whose surface is determined to be electrodeposited metal have diamond crystals that are coated with electrodeposited metal, etc., and do not contribute to machining.Therefore, by determining the performance of a diamond tool from these ratios, performance can be evaluated without actually performing machining.

[0017] In this case, in the spectroscopic measurement step, a laser having a wavelength of 532 nm can be used, and the laser output can be set to 10 mW or more and 30 mW or less.

[0018] Using a 532 nm laser provides a wavelength that is sufficient to detect peaks due to diamond crystals and amorphous carbon. In addition, because a 532 nm laser is a laser with a wavelength that is commonly used in Raman spectroscopy, there is no need to use special materials or structures as the light source.

[0019] By setting the laser output to 10mW or more, the measurement time per abrasive grain can be reduced to 10 seconds or less, improving throughput when measuring multiple abrasive grains simultaneously.By setting the laser output to 30mW or less, the influence of fluorescence from the wire or electrodeposited metal can be completely eliminated, allowing for more accurate measurements.

[0020] In this case, the diameter of the range irradiated with the laser in the spectroscopic measurement step can be set to the average diameter of the electrodeposited diamond abrasive grains.

[0021] The diamond abrasive grains that become the cutting edges during processing are partially buried in the electroplated metal and are only partially exposed. Therefore, by setting the diameter of the area irradiated with the laser to the average diameter of the diamond abrasive grains, the exposed areas of the diamond abrasive grains can be reliably detected.

[0022] In this case, in the calculation step, when the peak height of diamond is 10 times or less the peak height of amorphous carbon, it can be determined to be a composite peak.

[0023] This allows reliable calculation of a composite peak even when the diamond of an abrasive grain has been exposed and contributed to grinding, and a portion of the grain has been carbonized due to a reaction caused by processing heat, etc., meaning that the grain also contains amorphous carbon.

[0024] At this time, in the abrasive grain information acquisition process, the positions of traces of the diamond abrasive grains that have fallen off the surface can also be acquired as the positions of the abrasive grains that have been recognized as the diamond abrasive grains.

[0025] This allows not only the quality of the diamond abrasive grains but also the areas where diamond abrasive grains have fallen off and no longer contribute to grinding to be taken into account when evaluating performance, making it possible to determine the performance of diamond tools with greater accuracy.

[0026] The present invention also provides a method for evaluating the performance of a diamond tool for machining, which comprises carrying out the inspection method for a diamond tool for machining described above on a diamond tool for machining before and after a reference machining operation, comparing the performance of the diamond tool before and after the reference machining operation, and determining any change in performance of the diamond tool due to machining.

[0027] According to this performance evaluation method, the performance of the diamond tool before and after standard machining is compared using the above-mentioned inspection method for diamond tools for machining, so that when actual machining is performed, the degree of change in performance due to machining can be evaluated with high accuracy. [Effects of the Invention]

[0028] As described above, according to the method for inspecting a diamond tool for machining of the present invention, it is possible to evaluate the performance with high precision without actually carrying out machining. Furthermore, according to the method for evaluating the performance of a diamond tool for machining of the present invention, the degree of change in performance due to machining can be evaluated with high accuracy when machining is actually performed. [Brief explanation of the drawings]

[0029] [Figure 1] 1 shows a flow diagram of an inspection method for a diamond tool for machining according to an embodiment of the present invention. [Figure 2] 1 shows an example of a Raman spectrum obtained by Raman spectroscopy of diamond abrasive grains electrodeposited on the surface of a diamond tool. [Figure 3] 10 shows another example of a Raman spectrum obtained by Raman spectroscopy measurement of diamond abrasive grains electrodeposited on the surface of a diamond tool. [Figure 4] 1 shows a flow diagram of a method for evaluating the performance of a diamond tool for machining according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be described in detail below, but the present invention is not limited thereto.

[0031] As described above, there has been a demand for an inspection method for diamond tools for machining that use diamond abrasive grains and that allows performance to be evaluated without actually performing machining.

[0032] As a result of intensive research into the above-mentioned problems, the inventors have found that the performance of diamond tools can be evaluated without actually performing machining, and have completed the present invention. This invention is an inspection method for diamond tools for machining, comprising: a preparation step of preparing a diamond tool having diamond abrasive grains electrodeposited on the surface of a substrate; an abrasive grain information acquisition step of observing the surface and acquiring the positions of the abrasive grains recognized as diamond abrasive grains for each of the abrasive grains; a spectroscopic measurement step of performing Raman spectroscopy on the abrasive grains recognized as diamond abrasive grains; a calculation step of calculating, based on the results of the Raman spectroscopy measurement, the proportion of abrasive grains whose Raman scattered light has a main peak of diamond crystal alone, the proportion of abrasive grains whose main peak is a composite peak of diamond crystal and amorphous carbon, and the proportion of abrasive grains whose Raman scattered light has no peak, relative to the total number of the measured abrasive grains; and a determination step of determining the performance of the diamond tool based on the calculated proportions.

[0033] As described above, there has also been a demand for a method for evaluating the performance of diamond tools for machining, which is capable of evaluating with high accuracy the degree of change in performance due to machining when actual machining is performed.

[0034] As a result of extensive research into the above-mentioned problems, the inventors have discovered that a method for evaluating the performance of diamond tools for machining, which involves carrying out the above-described inspection method for diamond tools for machining on a diamond tool for machining before and after a reference machining process, comparing the performance of the diamond tool before and after the reference machining process, and determining the change in performance of the diamond tool due to machining, can accurately evaluate the degree of change in performance due to machining when actual machining is performed, and have completed the present invention.

[0035] Thus, the present invention relates to a method for inspecting and evaluating the performance of a diamond tool for machining in which diamond is used as an abrasive grain.

[0036] The following description will be made with reference to the drawings. First, a method for inspecting a diamond tool for machining according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3, but the present invention is not limited thereto.

[0037] <Inspection method for diamond machining tools> First, a diamond tool is prepared by electrodepositing diamond abrasive grains onto the surface of a substrate (S1 in Fig. 1, preparation step).

[0038] [About the evaluation subject] The inspection object of the method for inspecting a diamond tool for machining according to the embodiment of the present invention, i.e., the diamond tool prepared in step S1, is a tool having diamond abrasive grains electrodeposited on its surface with a metal (e.g., nickel). More specifically, the inspection object is the surface of the substrate of the tool having diamond abrasive grains electrodeposited on it.

[0039] Examples of the machining process include cutting and grinding. An example of a cutting tool is a fixed abrasive wire in which diamond abrasive grains are electrodeposited on the outer surface of a thin wire as a base.

[0040] An example of a grinding tool is a grinding wheel having diamond abrasive grains electrodeposited on the surface of a disk serving as a substrate.

[0041] Furthermore, the tool to be measured may be one or more.

[0042] Next, the surface of the prepared diamond tool on which the diamond abrasive grains are electroplated is observed, and the position of each abrasive grain that is recognized as a diamond abrasive grain is obtained (S2 in Figure 1, abrasive grain information acquisition process).

[0043] Specifically, the surface on which the diamond abrasive grains are electrodeposited is observed using an observation means such as a microscope, the particle-shaped portions are recognized as diamond abrasive grains, and their positions are obtained.

[0044] However, in this embodiment, Raman spectroscopy is carried out in the next step, so when using Raman spectroscopy microscope, for example, use laser Raman spectroscopy microscope with light source wavelength of 532nm as observation means, and select the diamond abrasive grain that is electrodeposited with metal on the surface of the substrate.Unless otherwise specified, the following explanation will be given using the case of using laser Raman spectroscopy microscope as an example.

[0045] Increasing the number of abrasive grains whose positions are acquired increases the accuracy of the inspection. On the other hand, reducing the number of abrasive grains whose positions are identified shortens the time required for the inspection. Therefore, the number of abrasive grains whose positions are acquired can be set appropriately, taking into account the balance between the accuracy of the inspection and the time required for the inspection.

[0046] As the number of times and duration of use of a diamond tool increases, the diamond abrasive grains will fall off the surface due to factors such as deterioration caused by the temperature during processing. In this case, in S2, the positions of the traces of diamond abrasive grains that have fallen off the surface can also be obtained as the positions of the abrasive grains recognized as diamond abrasive grains.

[0047] This allows not only the quality of the diamond abrasive grains but also the areas where diamond abrasive grains have fallen off and no longer contribute to grinding to be taken into account when evaluating performance, making it possible to determine the performance of diamond tools with greater accuracy.

[0048] Once the positions of the abrasive grains have been acquired, Raman spectroscopy is then performed on the abrasive grains that have been identified as diamond abrasive grains (S3 in Figure 1, spectroscopy measurement step). The specific procedure can be exemplified as follows.

[0049] [About measurements] In this embodiment, the positions of the Raman peaks of the abrasive grains whose positions have been detected in S2 are obtained at a plurality of points on the surface of the diamond tool for machining, for example, using a Raman spectroscopic microscope.

[0050] Specifically, for example, first, a laser Raman spectroscopic microscope with a light source wavelength of 532 nm is used to select the abrasive grains recognized as diamond abrasive grains in S2. A laser is irradiated onto these selected diamond abrasive grains, and the first-order Raman peak position (1333 cm when the abrasive grains are diamond alone) is determined from the acquired spectrum. -1 The data from one location (near the center of the abrasive grain) can be used as the position of the Raman peak. More specifically, when the position of the abrasive grain is identified in S2, Raman spectroscopy can be performed while maintaining that position.

[0051] Using a 532 nm laser provides a wavelength that is sufficient to detect peaks due to diamond crystals and amorphous carbon. In addition, because a 532 nm laser is a laser with a wavelength that is commonly used in Raman spectroscopy, there is no need to use special materials or structures as the light source.

[0052] When a laser with a wavelength of 532 nm is used, the laser output can be set to 10 mW or more and 30 mW or less.

[0053] By setting the laser output to 10mW or more, the measurement time per abrasive grain can be reduced to 10 seconds or less, improving throughput when measuring multiple abrasive grains simultaneously.By setting the laser output to 30mW or less, the influence of fluorescence from the wire or electrodeposited metal can be completely eliminated, allowing for more accurate measurements.

[0054] In this case, since the diamond that becomes the cutting edge during processing is only partially exposed, it is desirable that the diameter of the area irradiated with the laser, i.e., the spot diameter, be the average diameter of the raw diamond lot electroplated on the tool.

[0055] Next, based on the results of the Raman spectroscopy measurement, the percentage of abrasive grains whose Raman scattered light has a main peak of diamond crystals alone, the percentage of abrasive grains whose Raman scattered light has a main peak of a composite peak of diamond crystals and amorphous carbon, and the percentage of abrasive grains whose Raman scattered light has no peak and shows the electrodeposited metal are calculated relative to the total number of measured abrasive grains (S4 in Figure 1, calculation step).

[0056] The reason for classifying the abrasive grains into three types and calculating the ratios based on the results of Raman spectroscopy will be explained below.

[0057] In the research to complete the present invention, when the abrasive grains on the surface of the fixed abrasive wire were observed at several locations before the fixed abrasive grain slicing process, it was confirmed that the abrasive grains had been electroplated.

[0058] When the Raman peak value of this abrasive grain was measured, the diamond crystal peak 1333 (cm -1 ) was detected, indicating that it was either abrasive grains that appeared to be diamond crystals, or abrasive grains that did not detect a peak and whose entire surface appeared to be coated with electrodepositing metal (nickel).

[0059] In addition, when the abrasive grains on the surface of the fixed abrasive wire were observed at several locations after the fixed abrasive slicing process, it was found that there were places where the abrasive grains had been electroplated and places where the abrasive grains had fallen off and only the electroplated metal remained.

[0060] Raman spectroscopy was performed at these locations to measure the Raman peak values. The diamond crystal peak 1333 (cm -1 ) or the amorphous carbon peak at 1550 (cm -1 ) was detected, or no peak was detected.

[0061] The areas where no peaks were detected were traces of the electrodeposited metal (nickel) where abrasive grains had fallen off, but the amorphous carbon peak was also detected in areas where abrasive grains had been electrodeposited. This is thought to be because even in the abrasive grains where diamond was exposed and contributed to grinding, some of them were carbonized due to reactions caused by processing heat, etc., and also contained amorphous carbon.

[0062] In this way, by classifying abrasive grains into three types based on the results of Raman spectroscopy and calculating their proportions, it is possible to determine the proportion of diamond crystals that function as abrasive grains, the proportion of diamond crystals that have deteriorated and become amorphous, and the proportion of grains that no longer function as abrasive grains because their surfaces have been coated with electrodeposited metal or have fallen off the substrate, etc. Knowing these proportions also allows us to determine the machining ability of the tool and the degree of its deterioration. This is the reason why the abrasive grains are classified into three types and their proportions are calculated based on the results of Raman spectroscopy.

[0063] The main peak here is preferably defined as follows: Specifically, "the peak of the diamond crystal alone is the main peak" preferably means that the peak height of the diamond crystal is more than 10 times that of the amorphous carbon crystal. In other words, the state in which the diamond crystal is exposed from the electrodeposition metal is preferably defined as the peak height of the diamond crystal being more than 10 times that of the amorphous carbon crystal.

[0064] In addition, the composite peak includes both the diamond peak and the amorphous carbon peak, but it is preferable that the peak height of the diamond crystal is 10 times or less than the peak height of the amorphous carbon.In this case, when the composite peak is detected, it is determined that the composite peak is the main peak.

[0065] Examples of Raman spectra in which both diamond crystal peaks and amorphous carbon peaks are detected are shown in Figures 2 and 3. In both Figures 2 and 3, peaks that appear to be diamond crystal peaks and peaks that appear to be amorphous carbon peaks are detected.

[0066] However, in Figure 2, the peak height of the diamond crystal (normalized intensity in Figure 2) is more than 10 times the peak height of amorphous carbon, so it can be determined that the peak of the diamond crystal alone is the main peak being measured.

[0067] On the other hand, in Figure 3, the peak height of the diamond crystal is less than 10 times the peak height of the amorphous carbon, so it can be determined that the composite peak is the main peak of the measurement target.

[0068] Next, the performance of the diamond tool is judged based on the calculated ratio (S5 in FIG. 1, judgment step).

[0069] For example, when the diamond tool is a fixed abrasive wire, the results of the Raman peak observation using the Raman spectroscopic microscope described above show that the wire before the fixed abrasive slicing process has a diamond crystal peak of 1333 (cm -1 ) can be used to determine whether the cutting speed is fast or slow from the start of cutting when using these fixed abrasive wires. In other words, the cutting speed performance can be determined as a wire performance.

[0070] For example, when measuring the Raman peak of an unused wire of a diamond tool, if the majority of the abrasive grains do not produce a peak, that is, if the majority of the abrasive grains are completely coated with electrodeposited metal, it can be determined that even when cutting begins, the cutting speed will not increase, and will become slow, because the abrasive grains are coated with electrodeposited metal, until the metal coating the abrasive grains wears away and the diamonds are exposed.

[0071] In addition, when the diamond tool is a fixed abrasive wire, when the Raman peak of the wire after fixed abrasive slicing was measured, the diamond crystal peak 1333 (cm -1 ), the peak of the diamond crystal itself and the peak of amorphous carbon at 1550 (cm -1 When using these fixed abrasive wires, it is possible to determine whether the cutting speed can be increased or whether the cutting speed is too fast, based on the rate at which traces of the electrodeposited metal (nickel) are detected, where no peaks due to abrasive grains are detected, and the composite peak of

[0072] For example, when measuring the Raman peaks of wire after fixed abrasive slicing, the diamond crystal peak 1333 (cm -1 ) is the main peak, the diamond remains on the wire in an electrodeposited state without being worn away after cutting, which means that it is possible to further increase the cutting speed.

[0073] On the other hand, when measuring the Raman peaks of the wire after fixed abrasive slicing, the diamond crystal peak 1333 (cm -1 ) is the main peak of the abrasive grains, the diamond crystal peak and the amorphous carbon peak 1550 (cm -1 If the majority of abrasive grains have a composite peak of (3), it can be determined that the diamond has worn away and deteriorated into amorphous carbon during cutting. Since the diamond abrasive grains have deteriorated into amorphous carbon, it can be determined that if the cutting speed is increased any further, the abrasive grains are likely to fall off.

[0074] Furthermore, when measuring the Raman peaks of the wire after fixed abrasive slicing, the diamond crystal peak 1333 (cm -1 ) is the main peak of the abrasive grains, and the peak of diamond crystals is 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 If traces of the electrodeposited metal (nickel) with no detectable peaks dominate over the abrasive grains with the composite peak of () as the main peak, it can be determined that the diamond has worn away and deteriorated into amorphous carbon during cutting, and is then falling off. Since the diamond abrasive grains have deteriorated into amorphous carbon and are then falling off, it can be determined that the cutting speed is too fast and that it would be better to slow it down.

[0075] In this embodiment, the diamond abrasive grains are prepared in the preparation step (S1) and electroplated onto the surface of the substrate of a diamond tool such as a wire or wheel. In the abrasive grain information acquisition step (S2), the position of each abrasive grain is acquired, and in the spectroscopic measurement step (S3), Raman spectroscopic measurement is performed on the abrasive grains whose positions have been acquired in the abrasive grain information acquisition step (S2) while maintaining their positions.

[0076] Next, in this embodiment, based on the measurement results, the main peak is the diamond crystal peak 1333 (cm -1 ) or the diamond crystal peak 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 A calculation step (S4) is carried out to calculate the ratio of the abrasive grains to the total, whether it is a composite peak of the above or no peak (when measuring electrodeposited metal (nickel)), and the performance of the diamond tool such as a wire or grinding wheel is judged in a judgment step (S5) based on this ratio.

[0077] Therefore, Raman spectroscopy measurements are performed on multiple or more abrasive grains in diamond tools such as wires and grinding wheels, making it possible to reliably obtain the main peak of the Raman scattered light from each individual abrasive grain and evaluate its crystallinity.

[0078] Therefore, the more abrasive grains are evaluated, the more accurate the information on the abrasive grains electrodeposited on the wire or wheel will be.Furthermore, by measuring at multiple locations or using multiple samples, the information on the abrasive grains obtained will be even more accurate. The above is a description of the method for inspecting a diamond tool for machining according to the embodiment of the present invention.

[0079] Next, a method for evaluating the performance of a diamond tool for machining according to an embodiment of the present invention will be described with reference to FIG.

[0080] In the method for evaluating the performance of a diamond tool for machining according to an embodiment of the present invention, the inspection method for a diamond tool for machining according to the present invention is carried out on the diamond tool for machining before and after a reference machining process, and the performance of the diamond tool before and after the reference machining process is compared to determine the change in performance of the diamond tool due to machining.

[0081] Specifically, first, a diamond tool to be subjected to performance evaluation is prepared (S11 in FIG. 4). The diamond tool to be subjected to performance evaluation is the same as the diamond tool subjected to the inspection method for diamond tools for machining according to the present invention. However, it must be in a state before the reference machining is performed.

[0082] The reference processing is a processing for which the change in performance before and after processing needs to be evaluated. For example, it is the first processing performed using an unused diamond tool. If the reference processing is the first processing performed using an unused diamond tool, the diamond tool to be prepared will be an unused diamond tool.

[0083] Next, the prepared diamond tool is inspected (S12 in FIG. 4). Specifically, S1 to S5 in FIG. 1 are carried out on the prepared diamond tool to determine its performance.

[0084] Next, the inspected diamond tool is used to perform the reference processing (S13 in Figure 4). For example, if the diamond tool is a fixed abrasive wire, it is set in a wire saw device and a slicing process is performed to cut the silicon single crystal.

[0085] Next, the diamond tool after the standard machining is inspected (S14 in Fig. 4). Specifically, S1 to S5 in Fig. 1 are performed on the diamond tool after the standard machining to determine its performance.

[0086] Finally, the performance of the diamond tool before and after the reference machining is compared to determine the change in performance of the diamond tool due to machining (S15 in FIG. 4).

[0087] By using this performance evaluation method to compare and analyze performance before and after the use of standard cutting or grinding conditions (machining), for example, when introducing a new diamond tool, it is possible to compare its merits with the current diamond tool, and it is also possible to determine whether it is possible to increase the cutting speed or extend the service life of the diamond tool. [Example]

[0088] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. A silicon single crystal was cut using a fixed abrasive wire as a diamond tool for machining, and the performance before and after cutting was determined using the inspection method for diamond tools for machining of the present invention, and the difference in performance before and after cutting was compared using the performance evaluation method for diamond tools for machining of the present invention. The specific procedure is as follows.

[0089] (Example) In the examples, three types of fixed abrasive wires from companies A, B, and C were first prepared, and each wire was placed in a fixed abrasive wire saw device. A silicon single crystal with a diameter of 300 mm was cut under the following conditions: wire diameter 0.14 mm, wire tension 25 N, wire speed 1500 m / min, average wire feed speed 0.32 mm / min, cooling water temperature 23°C, and cooling water flow rate 150 l / min.

[0090] The wire before cutting and the abrasive grains on the wire surface after cutting were observed with a Raman microscope and Raman spectroscopy was performed. The Raman peaks were determined to be the diamond crystal peak 1333 (cm -1 ) single element is the main peak, or the diamond crystal peak 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 ) was measured to see if it was a main peak or if there was no peak (due to the electrodeposited metal), and the ratio of this to the total abrasive grains was calculated and evaluated.

[0091] (Comparative Example) In the comparative example, the three types of wires from companies A, B, and C that were cut in the example were observed with a Raman microscope for the abrasive grains on the wire surface before and after cutting, and Raman spectroscopy was performed. The Raman peaks were the peak of diamond crystal alone at 1333 (cm -1 The abrasive grains were classified into those in which a complex peak was detected and those in which no peak was detected (due to the electrodeposition metal), and the ratio of the measured abrasive grains to the total was calculated and evaluated. In other words, in the examples, the peaks judged to be composite peaks were judged to be peaks of diamond crystals alone in the comparative examples.

[0092] Table 1 shows the observation results and peak evaluation results of the wires before cutting and use in the examples and comparative examples.

[0093] [Table 1]

[0094] As is clear from Table 1, for both the examples and the comparative examples, the diamond crystal peak 1333 (cm -1 ) was obtained in over 80% of the abrasive grains, and no difference in performance was observed between the wires of companies A, B, and C.

[0095] Table 2 shows the observation results and peak evaluation results of the wires after cutting and use in the examples and comparative examples.

[0096] [Table 2]

[0097] As is clear from Table 2, in the examples, the wire of Company A had a peak of 1333 (cm -1 ) is the main peak of the abrasive grains, which accounts for more than 70% of the total, and the diamond crystal peak 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1) was the main peak of the composite peak of the abrasive grains, and less than 10% had no peak indicating that the electrodeposited metal had fallen off the abrasive grains.

[0098] From this, it was determined that Company A's wire retained sufficient diamond abrasive grains even after cutting, and had not deteriorated to amorphous carbon. This indicated that it was possible to increase the cutting speed beyond the above conditions. It was also determined that it was possible to extend the wire's life by keeping the cutting speed the same and slowing down the wire feed speed.

[0099] The wire from Company B has a peak of 1333 (cm -1 ) is the main peak of the abrasive grains, and the diamond crystal peak 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 ) was the main peak of the composite peak of the abrasive grains, while approximately 20% had no peak indicating that the abrasive grains had fallen off the electrodeposited metal.

[0100] From this, it was determined that the cutting speed was appropriate, although the diamond abrasive grains of Company B's wire had deteriorated to amorphous carbon more rapidly than the wire of Company A, and some abrasive grains had fallen off. On the other hand, it was assumed that if the cutting speed was made any faster, the deterioration and falling off of the abrasive grains would increase, and it was determined that it would be difficult to increase the cutting speed any further.

[0101] The wire from Company C has a peak of 1333 (cm -1 ) is the main peak of the abrasive grains, and the diamond crystal peak 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 ) was the main peak of the composite peak of the abrasive grains, while more than 50% had no peak indicating that the electrodeposited metal had fallen off the abrasive grains.

[0102] This shows that the diamond abrasive grains have deteriorated to amorphous carbon and fallen off due to cutting, with more than half of the abrasive grains having fallen off compared to before cutting. This indicates that the cutting speed is too fast. In other words, if the cutting speed is made any faster, the number of abrasive grains falling off will increase, and in the worst case scenario, the wire will break.

[0103] On the other hand, in the comparative example, the wire of Company A showed the peak of the single diamond crystal at 1333 (cm -1 ) was detected in over 90% of the abrasive grains, and less than 10% had no peak indicating that the abrasive grains had fallen off the electrodeposited metal. This indicates that sufficient diamond abrasive grains remained even after cutting, and degradation had not progressed. This indicates that it is possible to increase the cutting speed beyond the above conditions. It was also determined that it is possible to extend the life by, for example, slowing down the wire feed speed while keeping the cutting speed the same. However, unlike the examples, it was not possible to determine the degree of degradation of the diamond abrasive grains to amorphous carbon.

[0104] The wire of Company B, which is a comparative example, has a peak of 1333 (cm -1 ) was detected in approximately 80% of the abrasive grains, and 20% had no peaks indicating that the electrodeposited metal had fallen off. This indicates that some abrasive grains had fallen off during cutting, but at first glance it seemed possible to set the cutting speed even faster.

[0105] However, in the example, the wire of Company B after cutting showed a peak of diamond crystal at 1333 (cm -1 ) and the amorphous carbon peak at 1550 (cm -1 ) composite peak is the main peak, while the comparative example shows the peak of diamond crystal alone at 1333 (cm -1 ) were detected as abrasive grains, it was found that the comparative example was unable to capture the effects of these deteriorations.

[0106] The wire of Company C, a comparative example, showed a peak of 1333 (cm) of the diamond crystal alone even after cutting. -1) was detected in over 40% of the abrasive grains, and over 50% had no peak indicating the electrodeposited metal from which the abrasive grains had fallen. This shows that the diamond abrasive grains were falling off even after cutting, but about half of the abrasive grains remained.

[0107] At first glance, the cutting speed was deemed appropriate. Since about half of the abrasive grains remained, it seemed possible to increase the cutting speed even further. However, the results of the example showed that the diamond abrasive grains in Company C's wire had deteriorated and fallen off due to cutting, so if the cutting speed was increased any further, the abrasive grains would likely fall off more, and in the worst case scenario, the wire would likely break. In other words, it was found that the comparative example was unable to capture the effects of this deterioration.

[0108] As described above, according to the examples of the present invention, it was found that by using the inspection method for diamond tools for machining of the present invention, it is possible to evaluate the performance as if machining had been performed, even if actual machining has not been performed.

[0109] Furthermore, according to the embodiment of the present invention, by comparing the performance before and after processing, it was possible to determine the change in performance due to processing using a diamond tool for machining, in this case the degree of deterioration due to processing.

[0110] The present specification includes the following aspects. [1]: A method for inspecting a diamond tool for machining, comprising: a preparation step of preparing a diamond tool having diamond abrasive grains electrodeposited on the surface of a substrate; an abrasive grain information acquisition step of observing the surface and acquiring the positions of the abrasive grains recognized as the diamond abrasive grains for each of the abrasive grains; a spectroscopic measurement step of performing Raman spectroscopic measurement on the abrasive grains recognized as the diamond abrasive grains; a calculating step of calculating, based on the results of the Raman spectroscopy measurement, the ratio of the abrasive grains whose Raman scattered light has a main peak of diamond crystal alone, the ratio of the abrasive grains whose Raman scattered light has a main peak of a composite peak of diamond crystal and amorphous carbon, and the ratio of the abrasive grains whose Raman scattered light has no peak and exhibits an electrodeposited metal, relative to the total number of the measured abrasive grains; a determining step of determining the performance of the diamond tool based on the calculated ratio; 1. A method for inspecting a diamond tool for machining, comprising: [2]: In the spectroscopic measurement step, The method for inspecting diamond tools for machining according to [1] above, characterized in that a laser having a wavelength of 532 nm is used and the laser output is set to 10 mW or more and 30 mW or less. [3]: In the spectroscopic measurement step, The method for inspecting a diamond tool for machining according to [1] or [2] above, characterized in that the diameter of the area irradiated with the laser is set to the average diameter of the electroplated diamond abrasive grains. [4]: In the calculation step, The method for inspecting a diamond tool for machining according to any one of [1] to [3] above, characterized in that a composite peak is determined when the peak height of diamond is 10 times or less the peak height of amorphous carbon. [5]: In the abrasive grain information acquisition step, An inspection method for a diamond tool for machining according to any one of [1] to [4] above, characterized in that the positions of the traces of the diamond abrasive grains that have fallen off the surface are also acquired as the positions of the abrasive grains that have been recognized as the diamond abrasive grains. [6]: A method for evaluating the performance of a diamond tool for machining, characterized in that any of the inspection methods for diamond tools for machining described above in [1] to [5] is carried out on a diamond tool for machining before and after a reference machining is performed, and the performance of the diamond tool before and after the reference machining is compared to determine the change in performance of the diamond tool due to machining.

[0111] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. 1. A method for inspecting a diamond machining tool, comprising: a preparation step of preparing a diamond tool having diamond abrasive grains electrodeposited on the surface of a substrate; an abrasive grain information acquisition step of observing the surface and acquiring the positions of the abrasive grains recognized as the diamond abrasive grains for each of the abrasive grains; a spectroscopic measurement step of performing Raman spectroscopic measurement on the abrasive grains recognized as the diamond abrasive grains; a calculating step of calculating, based on the results of the Raman spectroscopy measurement, the ratio of the abrasive grains whose Raman scattered light has a main peak of diamond crystal alone, the ratio of the abrasive grains whose Raman scattered light has a main peak of a composite peak of diamond crystal and amorphous carbon, and the ratio of the abrasive grains whose Raman scattered light has no peak and exhibits an electrodeposited metal, relative to the total number of the measured abrasive grains; a determining step of determining the performance of the diamond tool based on the calculated ratio; 1. A method for inspecting a diamond tool for machining, comprising:

2. In the spectroscopic measurement step, 2. The method for inspecting a diamond tool for machining according to claim 1, wherein a laser having a wavelength of 532 nm is used and the laser output is set to 10 mW or more and 30 mW or less.

3. In the spectroscopic measurement step, 2. The method for inspecting a diamond tool for machining according to claim 1, wherein the diameter of the area irradiated with the laser is set to the average diameter of the electrodeposited diamond abrasive grains.

4. In the calculation step, 2. The method for inspecting a diamond tool for machining according to claim 1, wherein a composite peak is determined when the peak height of diamond is 10 times or less than the peak height of amorphous carbon.

5. In the abrasive grain information acquisition step, The method for inspecting diamond tools for machining according to claim 1, characterized in that the positions of the traces of the diamond abrasive grains that have fallen off the surface are also acquired as the positions of the abrasive grains recognized as the diamond abrasive grains.

6. A method for evaluating the performance of a diamond tool for machining, comprising: carrying out the inspection method for a diamond tool for machining described in any one of claims 1 to 5 on a diamond tool for machining before and after a reference machining; comparing the performance of the diamond tool before and after the reference machining; and determining any change in performance of the diamond tool due to machining.

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