Method and system for analyzing solid sample

Abstract

To provide an analysis method and an analysis system capable of analyzing a metal element in a wide range of samples without being limited by a shape and a surface state of the sample, especially surface roughness.SOLUTION: A method for analyzing a solid sample includes the step of: specifying an evaluation point by performing marking while observing the solid sample with a microscope observation device capable of marking; performing laser ablation on the evaluation point with a laser ablation device using a marked point as a mark; and detecting a metal element by an inductively coupled plasma mass spectrometer with respect to a sample vaporized or aerosolized by the laser ablation and derived from the evaluation point.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and system for analyzing a solid sample. [Background technology]

[0002] Foreign matter or defects that occur during the manufacturing process of industrial products, or particles or abnormalities that occur during the use of industrial products, can adversely affect the performance of industrial products. Metal element analysis is used to investigate the cause of such areas. To investigate the cause of a foreign matter, defect, particle, or abnormality, it is first necessary to identify the location of the area, and then perform element analysis.

[0003] Patent Document 1 discloses a method for analyzing particles, which is characterized in that a particle counter detects particles on the surface of an object to be analyzed and obtains their coordinates, a marking device places a mark around the detected particle based on the coordinate data, and an analyzer analyzes the particle using the mark placed by the marking device as a landmark. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-142541 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques have room for improvement in that there are limitations on the shape and surface condition of samples to which they can be applied, particularly on surface roughness.

[0006] An object of one aspect of the present invention is to provide an analytical method and system capable of performing metal element analysis on a wide range of samples without being limited by the shape and surface condition, particularly the surface roughness, of the sample. [Means for solving the problem]

[0007] In order to solve the above problems, a method for analyzing a solid sample according to one embodiment of the present invention includes the steps of identifying an evaluation location by marking the solid sample while observing it with a microscopic observation device capable of marking, performing laser ablation on the evaluation location with a laser ablation device using the marked location as a landmark, and detecting metal elements in the sample derived from the evaluation location that has been vaporized or aerosolized by laser ablation with an inductively coupled plasma mass spectrometry device.

[0008] Moreover, a solid sample analysis system according to one embodiment of the present invention includes a marking-capable microscopic observation device for identifying evaluation locations by marking the solid sample while observing it, a laser ablation device for performing laser ablation on the evaluation locations using the marked locations as landmarks, and an inductively coupled plasma mass spectrometry device for detecting metal elements in the sample derived from the evaluation locations and vaporized or aerosolized by laser ablation. Effect of the Invention

[0009] According to one aspect of the present invention, it is possible to provide an analysis method and an analysis system capable of performing metal element analysis on a wide range of samples without being limited by the shape and surface condition, particularly the surface roughness, of the sample. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of an analysis method and an analysis system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an image observed by a confocal laser microscope in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the present invention will be described below, but the present invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0012] [1. Analytical methods for solid samples] A method for analyzing a solid sample according to one embodiment of the present invention includes the steps of identifying an evaluation location by marking the solid sample while observing it with a microscopic observation device capable of marking, performing laser ablation on the evaluation location with a laser ablation device using the marked location as a landmark, and detecting metal elements in the sample derived from the evaluation location that has been vaporized or aerosolized by laser ablation with an inductively coupled plasma mass spectrometry device.

[0013] Foreign matter, defects, particles, abnormalities, etc. to be analyzed are collectively referred to as "foreign matter, etc." in this specification. In the method of acquiring position information of foreign matter, etc. using a particle counter, etc. as in Patent Document 1, there are limitations on the shape and surface condition of the sample that can be applied, especially the surface roughness. Acquisition of such position information (e.g., comprehensive coordinate acquisition) is generally targeted at samples having a flat surface. For example, it was difficult to acquire position information of foreign matter, etc. in an amorphous sample or a sample having a surface with unevenness larger than that of foreign matter, etc. In addition, when the acquired coordinate data is transferred to another analysis device, it is necessary to rigorously align the sample so that it matches the coordinate data in this other analysis device.

[0014] In contrast, the analysis method according to one embodiment of the present invention can first observe foreign matter, etc., using a microscope observation device, regardless of the shape and surface condition of the sample, particularly the surface roughness. In addition, by using a microscope observation device capable of marking, marking can be performed around the foreign matter, etc. Then, laser ablation can be performed using this marking as a guide. With this method, strict positioning is not required as in the case of using the above coordinate data. Furthermore, by using an inductively coupled plasma mass spectrometry device, metal elements originating from the evaluation location can be analyzed.

[0015] In addition, there are SEM-EDX and EPMA as devices that directly perform metal element analysis on solid samples, but their sensitivity is at the 100% level, which cannot be said to be highly sensitive. An analysis method according to one embodiment of the present invention utilizes a so-called LA-ICP-MS, which is a combination of laser ablation (LA) and inductively coupled plasma mass spectrometry (ICP-MS), and is capable of highly sensitive analysis. The analysis method further combines marking using a microscopic observation device, so that foreign matter that cannot be observed only by the sample observation camera of the laser ablation device can also be analyzed.

[0016] <1-1. Marking process> The analysis method includes a step of identifying an evaluation location by marking the solid sample while observing the solid sample with a microscopic observation device capable of marking. In this specification, this step is also referred to as a marking step. The evaluation location means a location to be evaluated, i.e., a location to be detected for metal elements. The evaluation location may include foreign matter or defects that occur during the manufacturing process of the solid sample, particles or abnormalities that occur due to the use of the solid sample, etc.

[0017] The solid sample, the evaluation portion, the foreign matter, etc. may contain a metal element. The metal element is not limited as long as it is an element that can be detected by an inductively coupled plasma mass spectrometry device, but examples thereof include lithium, sodium, potassium, magnesium, calcium, titanium, zirconium, chromium, molybdenum, manganese, iron, cobalt, nickel, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminum, and lead. The solid sample is not particularly limited, but examples thereof include products or parts in fields where minute foreign matter and the like are problematic, such as the fields of semiconductor manufacturing or high-performance battery manufacturing, or the fields of flat panel display manufacturing. According to the above-mentioned analysis method, it is also possible to observe samples with an indefinite shape or samples with surface irregularities larger than those of foreign matter.

[0018] Examples of the microscopic observation device capable of marking include a microscope capable of irradiating a laser and a microscope equipped with a probe. Examples of the microscope capable of irradiating a laser include a confocal laser microscope. Examples of the microscope equipped with a probe include an atomic force microscope.

[0019] The measurement accuracy (spatial resolution) of the microscope observation device can be on the order of nm. The microscope observation device is used to observe a solid sample and find foreign matter, defects, particles, abnormalities, and the like. The locations where these foreign matter, etc. are present are the targets of laser ablation and metal element analysis, which will be described later. In this specification, "identifying an evaluation location" means positioning the evaluation location by marking the vicinity of the location where the foreign matter, etc. are present.

[0020] The marking method is not particularly limited. Examples of the marking method include leaving a laser irradiation mark, a scratch mark with a probe, or a piercing mark with a probe. In this specification, the marked area itself may also be referred to as a "marking". Multiple markings may be placed near the evaluation area. Marking may be performed so that the evaluation area is located at the center surrounded by multiple markings. For example, markings may be placed at four points around the evaluation area.

[0021] The size of the marking is a size that can be observed by the sample observation camera of the laser ablation device described later, and may be, for example, 1 μm or more, and preferably 1 to 10 μm. Furthermore, multiple markings of different sizes may be applied. A relatively small marking (for example, a diameter of 1 μm or more and less than 5 μm) may be applied in the immediate vicinity of the foreign matter, etc. Furthermore, a larger marking (for example, a diameter of 5 to 10 μm) may be applied around this small marking. In this case, the sample observation camera of the laser ablation device used next to the microscopic observation device can narrow the observation range using the large marking as a mark for primary positioning, and the position of the foreign matter, etc. can be specified in more detail using the small marking as a mark.

[0022] <1-2. Laser ablation process> The analysis method includes a step of performing laser ablation on the evaluation location using a laser ablation device with the marked location as a guide. In this specification, this step is also referred to as a laser ablation step or LA step. The laser ablation device is also referred to as an LA device.

[0023] By irradiating the evaluation location with a laser using the LA device, the components contained in the evaluation location can be vaporized or aerosolized. These vaporized or aerosolized components are also called samples derived from the evaluation location. By introducing the samples derived from the evaluation location into an ICP-MS (described below), the metal elements contained in the evaluation location can be analyzed. It is also possible to perform laser ablation on multiple evaluation locations in a short period of time and evaluate the components derived from multiple evaluation locations together.

[0024] The LA device may include a laser light source, a sample observation camera, a sample cell, and a sample stage. The measurement accuracy (spatial resolution) of the sample observation camera of the LA device may be on the order of μm. Laser ablation is performed on the evaluation location using a marking of a size that can be observed by the sample observation camera of the LA device as a guide. This allows laser ablation to be performed on the evaluation location even if a foreign object or the like is too large to be observed by the sample observation camera of the LA device.

[0025] Examples of the laser in the LA device include femtosecond laser, nanosecond laser, picosecond laser, and attosecond laser. For example, YAG laser, Nd:YAG laser, Ti:Sapphire laser, Yb:KGW laser, and excimer laser. The laser light irradiation diameter (spot size) can be 2 to 400 μm.

[0026] A carrier gas can be introduced into the sample cell. The sample cell is also connected to the ICP-MS by a tube. Components vaporized or aerosolized by laser ablation are transported to the ICP-MS together with the carrier gas. Examples of carrier gas include helium and argon.

[0027] <1-3. Metal element detection process> The analysis method includes a step of detecting metal elements in a sample from the evaluation site that has been vaporized or aerosolized by laser ablation using an inductively coupled plasma mass spectrometer. In this specification, this step is also referred to as a metal element detection step.

[0028] In ICP-MS, an introduced sample is ionized using inductively coupled plasma (ICP) and mass spectrometry is performed. ICP-MS may include a plasma torch that generates ICP and a mass spectrometer. Examples of the mass spectrometer include a quadrupole mass spectrometer, a double focusing mass spectrometer, a time-of-flight mass spectrometer, and a tandem quadrupole mass spectrometer.

[0029] ICP-MS can detect metal elements contained in the evaluation area at the pg to ng level, for example. This makes it possible to infer the origin of foreign matter in the evaluation area.

[0030] <1-4. Quantitative analysis process> The analysis method may further include a step of converting the intensity of the detected metal element into a quantitative value. In this specification, this step is also referred to as a quantitative analysis step. For example, by comparing with a solid sample containing a known concentration of the contained metal element, a highly sensitive quantitative analysis taking into account the effect of the matrix can be performed.

[0031] <1-5. Other processes> The analysis method may also include other steps. For example, the analysis method may include a step of observing the evaluation location after analysis using a microscope. In this specification, this step is also referred to as a post-analysis observation step. By this step, for example, the ablation depth and area can be measured to obtain the volume of the evaluation location, and the amount of element (element concentration) per volume can be evaluated.

[0032] 1 is a diagram showing an outline of an analysis method according to one embodiment of the present invention. Step S1 corresponds to a marking step using a microscope observation device 1. Step S2 corresponds to an ablation step using a laser ablation device 2. Step S3 corresponds to a metal element detection step and a quantitative analysis step using an inductively coupled plasma mass spectrometry device 3 (ICP-MS). Step S4 corresponds to a post-analysis observation step using the microscope observation device 1.

[0033] [2. Solid sample analysis system] The solid sample analysis system according to one embodiment of the present invention includes a marking-capable microscopic observation device for identifying an evaluation location by marking the solid sample while observing it, a laser ablation device for performing laser ablation on the evaluation location using the marked location as a guide, and an inductively coupled plasma mass spectrometry device for detecting metal elements in the sample derived from the evaluation location and vaporized or aerosolized by laser ablation. Explanation of the matters already explained in [1. Solid sample analysis method] will be omitted.

[0034] 1 is a diagram showing an outline of an analysis system according to one embodiment of the present invention. The analysis system 10 includes a microscope observation apparatus 1, a laser ablation apparatus 2, and an inductively coupled plasma mass spectrometry apparatus 3.

[0035] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0036] An embodiment of the present invention may include the following features. <1> A method for analyzing a solid sample, comprising the steps of: identifying an evaluation location by marking the solid sample while observing it with a microscopic observation device capable of marking; performing laser ablation on the evaluation location with a laser ablation device using the marked location as a landmark; and detecting metal elements in a sample derived from the evaluation location that has been vaporized or aerosolized by laser ablation with an inductively coupled plasma mass spectrometry device. <2> Further comprising converting the intensities of the detected metal elements into quantitative values. <1> Analysis method. <3> The microscope observation device is a confocal laser microscope or an atomic force microscope. <1> or <2> The analytical method described in. <4> A system for analyzing solid samples, comprising: a marking-capable microscopic observation device for identifying evaluation locations by marking a solid sample while observing the solid sample; a laser ablation device for performing laser ablation on the evaluation locations using the marked locations as landmarks; and an inductively coupled plasma mass spectrometry device for detecting metal elements in a sample derived from the evaluation locations that has been vaporized or aerosolized by laser ablation. <5> The microscope observation device is a confocal laser microscope or an atomic force microscope. <4> The analysis system according to claim 1 . EXAMPLES

[0037] An embodiment of the present invention will now be described.

[0038] An organic EL element measuring 2.5 mm in diameter was prepared and observed using a confocal laser microscope (OPTELICS HYBRID manufactured by Lasertec Corp.) The observation conditions were a laser wavelength of 514 nm, a lens of 20x magnification, and a measurement time of approximately 1 to 6 minutes.

[0039] FIG. 2 is a diagram showing an image observed by a confocal laser microscope in an embodiment. A defect was observed in the area enclosed by a square in image 1000. Image 1001 is an enlarged view of the area enclosed by the square. Image 1002 is a further enlarged view of the area enclosed by the square in image 1001. Marking 101 is a marking for primary positioning to make it easier to find the defect when enlarged with a sample observation camera of a laser ablation device. For more detailed positioning, markings 102 are added at four points around defect 100. Image 1003 is a diagram in which the observation mode of image 1002 is changed to make it easier to grasp the three-dimensional structure of defect 100.

[0040] When analyzing with LA-ICP-MS, the defects can be observed using the marked areas as guides with the sample observation camera of the laser ablation device. Then, the laser can be irradiated with a laser from the laser ablation device, and metal element analysis can be performed by ICP-MS. [Industrial Applicability]

[0041] The present invention can be used for the analysis of metal elements originating from foreign matter in a solid sample. [Explanation of symbols]

[0042] 1. Microscope observation device 2. Laser ablation device 3. Inductively Coupled Plasma Mass Spectrometer 10 Analysis System

Claims

1. A step of identifying an evaluation location by marking the solid sample while observing the solid sample with a microscopic observation device capable of marking; a step of performing laser ablation on the evaluation area using a laser ablation device with the marked area as a guide; and detecting metal elements in a sample from the evaluation site that has been vaporized or aerosolized by laser ablation using an inductively coupled plasma mass spectrometer.

2. The analytical method according to claim 1 , further comprising the step of converting the intensities of the detected metal elements into quantitative values.

3. 3. The analysis method according to claim 1, wherein the microscope is a confocal laser microscope or an atomic force microscope.

4. a marking-capable microscope observation device for identifying an evaluation location by marking the solid sample while observing the solid sample; a laser ablation device for performing laser ablation on the evaluation portion using the marked portion as a guide; and an inductively coupled plasma mass spectrometer for detecting metal elements in a sample from an evaluation site that has been vaporized or aerosolized by laser ablation.

5. The analysis system according to claim 4 , wherein the microscope is a confocal laser microscope or an atomic force microscope.

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