JP2014153322A - Deposit analysis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of analyzing a deposit with high sensitivity by a laser plasma method.SOLUTION: A deposit detachment laser beam L2 is projected onto a sample S while making the beam pass through a capture member 55, and simultaneously the sample S is scanned under the capture member 55. A deposit is captured by the capture member 55 from a wide region of the sample S. Then, an adhesion surface of the capture member 55 is directed toward a laser irradiation side, and a plasma emission laser beam L1 is projected to cause a deposit F captured to emit light for performing light emission analysis.

Description

  The present invention relates to an analyzer for performing elemental analysis of substances attached to a solid surface such as semiconductors, metals, and insulators, and more particularly, to an attached substance for converting an attached substance on a solid surface into a plasma and analyzing an emission spectrum thereof. The present invention relates to an analyzer.

  In the semiconductor manufacturing process, maintaining the surface of a substrate such as a silicon wafer in a clean state is important for improving product quality and yield. Therefore, there is a need for a rapid and highly sensitive elemental analyzer for identifying a substance when the substance adheres to the substrate surface from the atmosphere or the outside. Further, not only in the semiconductor industry but also in industries that handle metals, glass, and other solid products, there is a need for a high-sensitivity analyzer for analyzing dirt on the product surface.

  Fluorescence X-ray analysis is known as a rapid surface analysis method, but this analysis method is not sufficiently sensitive as a method for analyzing surface deposits and dirt. For the purpose of analyzing dirt on product surfaces with high sensitivity. Is not applicable.

  In recent years, a laser ablation method (laser-induced plasma) is used to perform solid-state elemental analysis by irradiating a solid surface with a YAG laser (wavelength 1.06 μm) to perform laser ablation and measuring the emitted light of the generated plasma with a spectrum detector Spectroscopic analysis) has become known as a rapid and sensitive analytical technique. However, this method directly irradiates a solid surface with a laser beam having a high energy density to explosively evaporate, atomize, and excite the solid itself, thereby converting it into plasma, thereby performing elemental analysis. It cannot be used for elemental analysis of adhered substances adhering to the surface.

On the other hand, a laser plasma analysis method for surface deposits has been developed which utilizes the fact that the energy density threshold (laser ablation threshold) required to cause laser ablation differs for each substance. That is, the laser light source is a pulse carbon dioxide laser (also referred to as TEA-CO ₂ laser; wavelength 10.6 μm) having a wavelength longer than that of the YAG laser, and the output power (energy density) of the pulse carbon dioxide laser to be irradiated is set to an appropriate value. When irradiation is performed on the solid deposit, no ablation occurs on the metal surface constituting the substrate, and only ablation of the sample substance adhering to the substrate surface can be selectively generated. Further, when a pulse carbon dioxide laser is irradiated toward the metal surface at atmospheric pressure, gas plasma of atmospheric gas can be generated.
Therefore, a sample analysis method using laser ablation in which a pulsed carbon dioxide laser is irradiated toward the deposit on the surface of the substrate, and the particles of the deposit evaporated by laser ablation are analyzed so as to emit light in the gas plasma of the atmospheric gas. Is disclosed (see Patent Document 1).

In addition, in order to distinguish the type of plasma to be analyzed, a plasma in the case of analyzing a substance from the inside of a solid by ablation using a YAG laser or the like is called “laser-induced target plasma” and is called a pulsed carbon dioxide laser. The plasma in the case where the substance inside the solid is not converted into plasma (ablated) by using the above, and only the atmospheric gas is converted into plasma is called “laser-induced gas plasma”.
Therefore, in the analysis of the surface deposit described in Patent Document 1, only the deposit on the solid surface is evaporated by ablation by irradiation with a pulsed carbon dioxide laser, and particles of the evaporated deposit are caused to flow into the laser-induced gas plasma. Then, atomization and excitation make it plasma and analyze it.

  As an application example of the analysis method using the laser-induced gas plasma, as shown in FIG. 6, the surface of a hard body 101 (a metal that is difficult to generate ablation) when analyzing contaminants in soil. A linear groove 102 (a fine depression or hole) is formed in the substrate, and a soil 103 as a sample is adhered in the linear groove 102, and a pulse carbon dioxide laser 104 having a beam diameter straddling the linear groove 102 is directly applied. It is disclosed that plasma 105 is induced by irradiation and the plasma emission is analyzed (see Patent Document 2).

  According to the laser plasma analysis method using laser-induced gas plasma, a pulse carbon dioxide laser is directly irradiated on a metal surface (Patent Document 1) or a hard body surface (Patent Document 2) serving as a substrate, Gas plasma of atmospheric gas is generated without generating ablation of the hard body itself. In addition, the attached carbon dioxide laser is directly irradiated to the adhered substances (adhered soil, etc.), causing ablation of the adhered substances, and the sample particles evaporated from the adhered substances flow into the gas plasma and emit light. The emission spectrum analysis of the attached substance is performed, and the elemental analysis is performed quickly and with high sensitivity.

  By the way, the solid surface itself directly irradiated with the pulse carbon dioxide laser is considerably damaged as a result of being directly irradiated with the pulse carbon dioxide laser having such an energy density that the ablation of the deposit is generated even if no ablation occurs. It will be.

  In addition, when analyzing substances adhering to the surface of a semiconductor substrate or the like, it is required to analyze the adhering material without damaging the substrate surface itself, so that the adhering material is not damaged as much as possible. An analysis method capable of performing the analysis is required. Similar requirements are not limited to the analysis of semiconductor substrates, but are also required in the analysis of various solid surfaces.

Therefore, the inventors have previously filed a prior application (Japanese Patent Application No. 2012-233116) for an invention of an attached matter analyzer that can analyze attached matter without damaging the solid surface.
The analyzer described in this prior application will be described with reference to the drawings. FIG. 7 is a diagram showing the configuration of the deposit analysis apparatus 10 described in the above document in plan view, and FIG. 8 is an enlarged view of the vicinity of the sample surface.
First, the apparatus configuration will be described. The deposit analysis apparatus 10 includes a chamber 11 for covering the sample S with an atmospheric gas (for example, He gas), a table 12 on which the sample S is placed in the chamber 11, a laser light source 13 used for generating plasma, and the sample S. A metal mesh 14 (metal sheet member having a vent hole) installed so as to cover the surface of the metal mesh 14, and a first optical path L 1 for obliquely irradiating the metal mesh 14 with a laser beam emitted from the laser light source 13. A first irradiation optical system 15 (laser beam oblique irradiation optical system) that performs optical path adjustment and condensing, a part of the laser beam from the laser light source 13 is branched, and the metal mesh 14 is directed from a different direction from the first irradiation optical system. A second irradiation optical system 16 (auxiliary laser beam irradiation optical system) that performs optical path adjustment and condensing to form a second optical path L2 to be directed toward the light, and light for detecting plasma emission Spectrum measuring section 17, and a control unit 18 for processing the control and measurement data of the entire device.

  As the laser light source 13 for generating plasma, a pulse carbon dioxide laser having a wavelength of 10.6 μm, a pulse width of several nanoseconds to several hundred nanoseconds, and a pulse energy of several mJ to several J is used.

The metal mesh 14 of the sheet member is attached so as to cover the sample surface in the region to be analyzed. The sample surface is preferably installed with a gap of about 1 mm, but it may be brought into direct contact with the surface. The metal mesh 14 may be a metal material that is unlikely to ablate. Specifically, for example, platinum, copper, stainless steel, or the like is used.
As shown in FIG. 9, the metal mesh 14 is formed with an opening 14b (space serving as a vent) knitted in a lattice shape, and when the laser beam in the first optical path L1 is obliquely irradiated. As shown in FIG. 10, the sample surface F is shaded by the thin wire 14a so that the laser beam from the first optical path L1 is not directly irradiated.

  The first irradiation optical system 15 (laser beam oblique irradiation optical system) includes a condenser lens 15a, a beam splitter 15b (optical path dividing means), and an attenuator 15c (attenuator) for adjusting laser power. The laser beam of the first optical path L1 irradiated from the laser light source 13 is irradiated obliquely to the sheet surface of the metal mesh 14 set in the chamber 11 and condensed near the sheet surface. I have to do it. The beam splitter 15b divides the optical path so that the intensity ratio of the output power of the irradiation light on the first optical path L1 and the irradiation light on the second optical path L2 of the second irradiation optical system 16 is about 10: 1. The beam splitter 15b is removed when the second irradiation optical system 16 is not used.

  The second irradiation optical system 16 (auxiliary laser beam irradiation optical system) includes a condenser lens 16a, mirrors 16b and 16c, and an attenuator 16d for laser power adjustment, and irradiation light from the laser light source 13 divided by the beam splitter 15b. Is irradiated to the metal mesh 14 from the direction different from the condenser lens 15a through the condenser lens 16a as a second optical path L2. The laser beam irradiated from the condensing lens 16a in the second optical path L2 passes through the vent (opening 14b) of the metal mesh 14 and is directly irradiated onto the surface of the sample S. That is, the energy ratio of the laser beam is sufficiently reduced by reducing the split ratio of the beam splitter 15b, and the sample surface is incident at an angle of direct irradiation so as not to damage the sample surface. Energy that promotes the detachment of the adhering substance from the sample surface is given without ablating the adhering substance on the sample surface. The second irradiation optical system 16 is a laser beam used only for the purpose of accelerating the detachment of deposits, and therefore has an energy density that does not generate gas plasma even when irradiated alone.

The optical spectrum measurement unit 17 includes an optical spectrum measurement device 17a (OMA) and an optical fiber 17b that guides light emission of plasma in the chamber 11 to the optical spectrum measurement device 17a.
The optical spectrum measuring instrument 17a includes a spectroscope and a photodiode array photodetector capable of simultaneously measuring multiple wavelengths, and can simultaneously measure plasma emission in the wavelength range to be measured.

Next, the analysis operation by the deposit analyzer 10 will be described. As shown in FIGS. 7 and 8, a metal sheet member 14 having a vent is placed on the surface of the solid sample S to be analyzed. Then, a plasma generating laser beam L1 (laser beam of the first optical path L1) capable of turning the atmospheric gas in the vicinity of the sheet member 14 into gas plasma is irradiated to the metal surface of the sheet member 14 from an oblique direction, The laser beam L1 is irradiated so as not to be directly irradiated onto the surface of the solid sample S (in the shadow of the thin line 14a). As a result, the atmosphere gas in the vicinity of the sheet member is turned into gas plasma without causing ablation of the sheet member 14 itself and without damaging the solid sample S (substrate). The generated gas plasma includes a plasma formed by desorption of deposits on the surface of the solid sample S.
At this time, apart from the laser beam L1 for generating plasma, a desorption laser beam L2 (a second optical path whose energy density is sufficiently small and does not damage the solid surface) as an auxiliary for desorbing deposits on the solid surface. L2 laser beam) may be directly irradiated onto the solid surface through the vent of the sheet member 14 to promote the desorption and plasmatization of the deposits.
And the emission spectrum of the light emission resulting from the adhered substance on the solid surface contained in the gas plasma generated in the vicinity of the metal surface of the sheet member 14 is measured, and the adhered substance is not damaged to the solid sample S (substrate) itself. I try to analyze it.

JP 2004-301573 A JP 2008-014843 A

  When performing the spectrum analysis of the deposit, the laser plasma analysis method described in Patent Document 1 and Patent Document 2 damaged the solid sample (substrate). However, the prior application (Japanese Patent Application No. 2012-233116) The deposit analysis device described in (1) can analyze deposits without damaging the surface of the solid sample. However, the prior application has problems to be further improved in the following points.

In order to further improve the detection sensitivity of the adhered matter, it is effective to increase the amount of plasma luminescence caused by the adhered matter. In order to increase the amount of plasma emission, it is necessary to widen the plasma generation area. For this purpose, it is necessary to increase the output power of the laser light source so that the laser irradiation area can be increased. This leads to an increase in size and cost of the laser optical system.
On the contrary, since it is desirable that the apparatus is originally downsized, as a laser light source for generating plasma, we would like to adopt a small laser light source that suppresses the output of light irradiation, but if the output of light irradiation is extremely suppressed, Plasma generation can become unstable.

Further, in the case of performing laser irradiation for generating plasma while irradiating an auxiliary laser beam for detaching deposits (a laser beam having a sufficiently low energy density and not damaging the solid surface), as shown in FIG. The light emitted from one laser light source is branched into two optical paths, or two independent laser light sources are required. In any case, the configuration of the laser optical system is complicated.
Furthermore, when irradiating the auxiliary laser beam for deposit removal, depending on the analysis target, it is necessary to adjust the timing of irradiating the two laser beams, such as irradiating immediately before irradiating the plasma generating laser beam. This is troublesome because it is necessary to provide a timing circuit and set the timing.

  Therefore, the present invention aims to further improve the above-described deposit analyzer and to improve detection sensitivity, downsize and simplify the apparatus configuration.

The present inventors examined each process in laser plasma analysis in order to solve the above problems. In the conventional method, the adhering substance desorbed from the surface of the solid sample is immediately excited and emitted in the plasma generated in the vicinity of the solid surface to be detected. On the other hand, in the laser plasma analysis of the present invention, the separation (evaporation) process for desorbing the deposit and the process for performing the emission analysis using plasma can be performed by separating them completely in time. A device was devised to once capture the separated adhering substance, and after the trapping, a plasma emission was generated in a separate process, and an apparatus for emitting and analyzing the trapped deposit in the plasma was adopted.
That is, the deposit analyzer of the present invention made to solve the above-mentioned problems is an deposit analyzer that analyzes a substance deposited on the surface of a solid sample by converting it into plasma, and the solid sample is placed on the deposit analyzer. And a table provided with a scanning mechanism for moving the solid sample along the surface direction, a laser light source and an attenuator for adjusting the output power of the laser beam from the laser light source, A first output power capable of generating plasma by gas plasma, and a second output power that is smaller than the first output power and capable of desorbing deposits when irradiated on the surface of the solid sample. A laser irradiation optical system that switches and irradiates output power with the attenuator, and is arranged so as to face the surface of the solid sample at a position above the solid sample A capture member that passes the laser beam irradiated with the second output power to irradiate the solid sample and captures the deposits detached from the surface of the solid sample at a capture surface facing the solid surface; The capture surface of the capture member can be held toward the solid surface, and the capture surface where the deposits are captured is reversed and held in a state directed toward the laser irradiation side. Measures the emission spectrum of the plasma generated by laser irradiation at the first output power, with the capture member front and back reversal holding mechanism possible and the capture surface where the adhering matter was captured facing the laser irradiation side And a spectrum measuring unit for performing the above.

According to the present invention, a solid sample with a deposit to be analyzed is placed on a scannable table. At the upper position of this solid sample (may be the upper position of a part of the solid sample), the capture member is held so as to face the surface of the solid sample by the capture member front / back reversal holding mechanism. The laser irradiation optical system first emits a laser beam with a second output power, passes through a capturing member, and irradiates a solid sample. Thereby, the deposit on the solid surface is desorbed and is attached to the capture surface (the surface facing the solid sample surface) of the opposing capture member. Note that the laser beam irradiated with the second output power is set to an output power that does not affect the solid surface even if the deposit can be detached from the solid surface even if the solid surface is directly irradiated. At this time, by irradiating the laser beam while scanning the table, even if the area of the capture member is small, deposits from a wide solid surface can be concentrated and adhered to the capture surface of the capture member. As a result, the deposits from the scanned solid sample surface are concentrated and deposited on the capture surface.
Subsequently, the capturing member front / back reversing holding mechanism holds the capturing member in a state in which the capturing surface where the deposit is captured is reversed. That is, it is held by manual or automatic operation so that the capture surface faces the laser irradiation side. In this state, the laser irradiation optical system emits a laser beam with the first output power, thereby generating plasma by converting the atmospheric gas into gas plasma on the capturing surface of the capturing member. At this time, the adhering matter adhering to the trapping surface is also turned into plasma and emits light in the plasma. Although the first output power can generate gas plasma, it is set so as not to cause ablation of the capturing member itself, so that it is not affected by substances constituting the capturing member itself.
And the emission spectrum derived from a deposit | attachment can be detected by measuring the plasma light-emitted in this way in a spectrum measurement part.

According to the present invention, the solid sample is irradiated with the desorption laser beam (laser beam with the second output power) so as to pass through the capturing member, and the deposit existing on the capturing surface of the capturing member is captured. At that time, the table can be scanned to remove the deposits from a large area of the solid sample and be intensively captured on a small capturing surface. When the deposit is emitted in the plasma by irradiation with a laser beam, the amount of light emitted by the deposit also increases, and the detection sensitivity can be increased.
From another point of view, even if the area irradiated with the laser for generating the plasma is a narrow area only on the capture surface, the deposits adhering to a wide range of solid sample surfaces are concentrated in the area. Therefore, it is possible to detect with a small area by a small laser light source with substantially the same sensitivity as large area irradiation without irradiating a large area with a high power laser light source. Can do.

In addition, according to the present invention, the desorption laser beam and the plasma generation laser beam are emitted from the same light source, and only the output power is adjusted by the attenuator. Adjustment work and the like are also facilitated.
In addition, according to the present invention, the desorption process for desorbing the deposit from the solid sample and depositing it on the capture member and the subsequent emission analysis process are completely separated, so desorption and emission of the deposit. This eliminates the need to adjust the timing and facilitates the analysis operation.

  In the above invention, the capturing member may be a window material capable of transmitting the laser beam having the second output power. That is, a material that transmits light of the wavelength may be used depending on the wavelength of the laser light to be irradiated. Specifically, when a pulse carbon dioxide laser is used as the laser light source, ZnSe, Ge, or the like can be used as the window material.

In the above invention, the capturing member may be a metal mask formed with a slit through which a laser beam of the second output power passes, or a mesh formed of a thin metal wire.
When the laser beam with the second output power is irradiated, a part of the laser beam is irradiated to the surface of the solid sample through the opening of the slit or mesh, and the detachment of the deposit can be promoted.

In the above invention, the capturing member front / back reversing holding mechanism may include a rotation mechanism for rotating the capturing member.
Thereby, the capture member can be mechanically inverted.

The figure which shows the whole structure of the deposit | attachment analyzer which is one Embodiment of this invention. The figure explaining the procedure at the time of analyzing with the capture member of a metal mesh. The figure which shows an example of the window material which can permeate | transmit a laser which is a capture member. The figure explaining the procedure at the time of analyzing a window material as a capture member. The flowchart which shows the procedure in the case of measuring a some sample. The figure which shows the conventional plasma analysis method using a laser induction gas plasma. The figure which shows the structure of the deposit | attachment analyzer of prior invention which becomes a premise of this invention by planar view. The figure which expands and shows the sample surface vicinity in the apparatus of FIG. The figure which shows an example of a metal mesh. The figure which shows the relationship between the metal mesh in prior invention, and the laser beam irradiated to this.

  Hereinafter, the deposit analyzer according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a deposit analyzer 50 according to an embodiment of the present invention.

  The deposit analysis apparatus 50 mainly includes a chamber 51 for covering the sample S with atmospheric gas, a table 52 on which the sample S is placed in the chamber 51, and the table 52 in a two-dimensional direction along the surface of the sample S. A table scanning mechanism 53 for moving, a laser irradiation optical system 54 for outputting a laser beam L used for desorption and plasma generation of deposits, and a sample S for capturing deposits desorbed from the sample S. The capture member 55 mounted on the optical path irradiated with the laser beam L at the upper position, the rotation holding mechanism 56 that holds the capture member 55 and reverses it upside down, and adjusts the height position of the capture member 55 from the sample S. Elevating mechanism 57, spectrum measuring unit 60 comprising fiber 58 and OMA 59 for measuring the emission spectrum, control of the entire apparatus, and measurement data And a control unit 61. which performs management.

The chamber 51 has a structure that can be sealed by a container body and a lid (not shown). A window 51a for allowing the laser beam L to pass through is formed in the container body. Further, a gas inlet 51b for connecting a cylinder (not shown) for supplying an atmospheric gas is provided so that a desired atmospheric gas can be filled during measurement. Any component that is not included in the deposit to be analyzed can be used as the atmospheric gas. Among them, the analytical sensitivity is that the He gas that has a long plasma emission life and can easily increase the SN ratio is used as the atmospheric gas. From the viewpoint of Alternatively, easily available N ₂ gas may be used as the atmospheric gas, or the atmosphere (air) itself may be used as the atmospheric gas if noise is not a problem. Note that the pressure of the atmospheric gas is preferably measured at a substantially atmospheric pressure because strong light-emitting plasma can be concentrated and generated in the vicinity of the analysis region.

  A table 52 provided in the chamber 51 is configured to hold the sample S in a horizontal state by a fixture (not shown). The table 52 can be translated in a two-dimensional direction by the table scanning mechanism 53, and the surface portion of the sample S can be moved to a position immediately below the capturing member 55. Further, when it is desired to avoid laser irradiation, the sample S can be retracted from a position directly below the capturing member 55.

  The laser irradiation optical system 54 includes a laser light source 62, an attenuator (attenuator) 63, and a lens 64. As the laser light source 62, a pulse carbon dioxide laser suitable for gas plasma generation having a wavelength of 10.6 μm, a pulse width of several nanoseconds to several hundred nanoseconds, and a pulse energy of several mJ to several J is used. A laser light source having a wavelength of 5 μm or more can be used without any problem for generating gas plasma. A shutter (not shown) is provided in front of the exit of the laser light source 62 so that the laser can be irradiated by opening the shutter when necessary.

  The attenuator 63 is configured so that the output power of the laser beam emitted from the laser light source 62 can be reduced at a desired attenuation rate as necessary. In the present embodiment, irradiation is performed with attenuation of about 1/5 to 1/20, preferably 1/10. Here, a variable attenuator (variable attenuator) is used so that the output power can be switched between large and small according to a control signal from the control unit 61. That is, when generating gas plasma, irradiation is performed with the first output power without being attenuated, and when deposits are detached, the attenuator 63 is operated to make it smaller than the first output power (for example, about 1/10). Irradiation is performed with the attenuated output power and the second output power capable of promoting the detachment of the deposit.

  The lens 64 adjusts the optical path adjustment of the laser beam and the aperture of the light beam so that the laser beam emitted from the attenuator 63 is irradiated toward the capturing member 55.

The capturing member 55 is mounted on the optical path on which the laser beam L is irradiated immediately above the sample S with a slight gap (for example, 1 mm to 10 mm) from the sample surface.
In the present embodiment, the metal mesh 14 (see FIG. 9) is used as the capturing member 55. The metal mesh 14 may be a metal material that is unlikely to ablate. Specifically, for example, platinum, copper, stainless steel, or the like is used.
As shown in FIG. 9, the shape of the metal mesh 14 is such that, for example, fine wires 14a having a wire diameter of about 0.05 to 0.2 mm are knitted in a lattice shape to form an opening 14b (a space serving as a vent). The mesh has a porosity of about 40 to 80%. When the laser beam is irradiated, a part of the laser beam passes through the opening 14b and is irradiated on the sample S.
Instead of the metal mesh 14, a mask in which a large number of pores are punched out in a metal plate or a mask in which a large number of slits are formed in a metal plate may be used.

  The capturing member 55 is rotatably supported by a rotation holding mechanism 56, and the rotation holding mechanism 56 is supported by the chamber 51 so as to be movable in the vertical direction by an elevating mechanism 57. The rotation holding mechanism 56 and the lifting mechanism 57 are driven by a control signal from the control unit 61.

The spectrum measuring unit 60 includes an optical spectrum measuring device 59 (OMA) and an optical fiber 58 that guides light emission of plasma in the chamber 51 to the optical spectrum measuring device 59.
The optical spectrum measuring instrument 59 includes a spectroscope and a photodiode array photodetector capable of simultaneously measuring multiple wavelengths, and can simultaneously measure plasma emission in the wavelength range to be measured.

  The control unit 61 is composed of a personal computer and controls the entire apparatus and analyzes and displays the emission spectrum data acquired by the optical spectrum measuring device 59.

  Next, the measurement operation by the deposit analyzer 50 will be described. FIG. 2 is a diagram schematically showing each stage of the measurement operation. For convenience of explanation, FIG. 2 shows the sample S and the capturing member 55, and the table 53 is not shown.

First, in the chamber 51 filled with He gas, the sample S is fixed to the table 52, and as shown in FIG. 2A, a part of the sample S is arranged immediately below the capturing member 55 (metal mesh 14). So that The deposit F is attached to the surface of the sample S. The attenuator 63 (see FIG. 1) is switched so that irradiation can be performed with the second output power that is an output when the deposit F is desorbed. In this state, the laser light source 62 performs irradiation with the laser beam L2 having the second output power.
The laser beam L2 is applied to the capturing member 55 (metal mesh 14), and part of the laser beam L2 passes through and is applied to the sample S. The deposit F evaporates by laser irradiation, and a part of the evaporated deposit adheres to and is captured by the lower surface of the opposing capture member 55. At this time, the table 52 is scanned so that a large area of the sample S is directly below the capturing member 55 so that a wide range of deposits F is captured by the capturing member 55.

  When the deposit F on the sample S is almost evaporated, the laser irradiation with the second output power is stopped. At this stage, as shown in FIG. 2B, the deposit F is attached to the lower surface of the capturing member 55 (metal mesh 14).

  Subsequently, as shown in FIG. 2C, the sample scanning mechanism 53 retracts the sample S (table 52) from directly below the capturing member 55 as necessary, and then operates the rotation holding mechanism 56 to capture the capturing member 55. It is reversed so that the deposit F attached to the top faces upward. When there is a possibility that the capture member 55 and the sample S (or the table 52) collide during reversal, the capture member 55 is reversed from the sample S by the lifting mechanism 57. At this time, in order to avoid a collision, the capture member 55 may be manually reversed and then held by the rotation holding mechanism 56 again.

  Subsequently, the operating state of the attenuator 63 is switched so that laser irradiation with the first output power can be performed. As shown in FIG. 2D, the capturing member 55 (metal mesh 14) is irradiated with the laser beam L1 having the first output power. Thereby, gas plasma P by the atmospheric gas (He gas) is generated in the vicinity of the upper surface of the capturing member 55. At this time, the deposit F on the upper surface of the capturing member 55 is also turned into plasma and emits light in the atmospheric gas.

The plasma emission is collected by the optical fiber 58 of the spectrum measuring unit 60, and spectrum data is collected by the optical spectrum measuring device 59.
By performing the emission analysis of the deposit F in this manner, the deposit F that has adhered to the entire surface of the sample S can be intensively adhered to the capture member 55 to emit light. Will be able to do.

Next, a modified example of the present invention will be described. In the embodiment described above, the metal mesh 14 is used as the capturing member 55, but instead of this, a window material that transmits a laser beam can be used as the capturing member 55.
FIG. 3 is a view showing an example of the window material, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a front view. The window material 66 is made of ZnSe or Ge that can transmit a carbon dioxide laser with a wavelength of 10.6 μm, and can be held by the rotation holding mechanism 56 shown in FIG. 1 by forming the same shape as the metal mesh 14 shown in FIG. It is.

  FIG. 4 is a diagram schematically showing each stage of the measurement operation when the window member 66 shown in FIG. 3 is used, as in FIG. Here too, for convenience of explanation, the sample S and the capturing member 55 are shown, and the table 53 is not shown.

First, the sample S is fixed to the table 52, and as shown in FIG. 4A, a part of the sample S is arranged immediately below the capturing member 55 (window member 66). The deposit F is attached to the surface of the sample S. The attenuator 63 (see FIG. 1) is switched so that irradiation can be performed with the second output power that is an output when the deposit F is desorbed. In this state, the laser light source 62 emits the laser beam L2 having the second output power.
The laser beam L2 is applied to the capturing member 55 (window member 66), but is transmitted (passed) therethrough and applied to the sample S. The deposit F is evaporated by the laser irradiation, and the evaporated deposit adheres to and is captured by the lower surface of the capture member 55 (window member 66) facing the deposit F. In the case of the window material 66, since it can be captured on the entire surface of the window material, the deposit F can be attached more efficiently than in the case of the metal mesh 14 shown in FIG. At this time as well, the table 52 is scanned so that a large area of the sample S comes directly under the capturing member 55 so that a wide range of deposit F is captured by the capturing member 55.

  When the deposit F on the sample S is almost evaporated, the laser irradiation with the second output power is stopped. At this stage, as shown in FIG. 4B, the deposit F is attached to the lower surface of the capturing member 55 (window member 66).

  Subsequently, as shown in FIG. 4C, after the sample S is retracted from just below the capturing member 55 by the table scanning mechanism 53 as necessary, the rotation holding mechanism 56 is operated to attach the sample S to the capturing member 55. The kimono F is inverted so that it faces up.

  Subsequently, the operating state of the attenuator 63 is switched so that laser irradiation with the first output power can be performed. Then, as shown in FIG. 4D, the capturing member 55 (window member 66) is irradiated with the laser beam L1 having the first output power. Thereby, gas plasma P by the atmospheric gas (He gas) is generated near the upper surface of the capturing member 55 (window member 66). At this time, the deposit F on the upper surface of the capturing member 55 (window member 66) is also turned into plasma and emits light in the atmospheric gas.

The plasma emission is collected by the optical fiber 58 of the spectrum measuring unit 60, and spectrum data is collected by the optical spectrum measuring device 59.
By performing the emission analysis of the deposit F in this way, the deposit F attached to the entire surface of the sample S can be intensively attached to the capturing member 55 (window member 66) to emit light. It becomes possible to perform highly sensitive measurement.

  Next, an application example in the case of analyzing a plurality of samples will be described. In the present invention, the process of desorbing the deposit F from the sample S and attaching it to the capture member is completely separated from the process of performing the emission analysis of the deposit F on the capture member. Therefore, when analyzing a plurality of samples S, a plurality of capture members 55 are prepared, so that the plurality of samples S are attached to the respective capture members 55 while replacing the capture members 55 for each sample S. The process of attaching the kimono is performed first, and the plurality of capture members 55 to which the deposit F is adhered can be subjected to emission analysis one after another.

FIG. 5 is a flowchart for explaining a procedure when analyzing the plurality of samples S.
The same number of capturing members 55 as the number of samples S are prepared (S101). The sample S is set in the apparatus one by one, and a capturing process for attaching the deposit F to the capturing member 55 by performing laser irradiation with the second output power is executed (S102). The capturing process is repeated until the capturing process for all the samples S is completed (S103).
Thereafter, the capturing members 55 that have captured the deposit F are set in the apparatus one by one, and laser emission is performed with the first output power to perform an emission analysis process (S104). The emission analysis process is repeated until the emission analysis process is completed for all the capturing members 55 that have captured the deposit F (S105).
With such a processing procedure, a plurality of samples S can be analyzed efficiently.

  Although the present invention has been described above, modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 50 Deposit | attachment analyzer 51 Chamber 52 Table 53 Table scanning mechanism 54 Laser irradiation optical system 55 Capture member (metal mesh, window material)
56 Rotation holding mechanism 57 Elevating mechanism 60 Spectrum measuring unit 61 Control unit 62 Laser light source (pulsed carbon dioxide laser)
63 Attenuator L1 Laser beam with first output power (for plasma emission)
L2 Laser beam with second output power (for deposit removal)
F deposit S sample

Claims (4)

A deposit analyzer that analyzes a substance deposited on the surface of a solid sample by converting it into a plasma.
A table provided with a scanning mechanism for placing the solid sample and moving the solid sample along the surface direction;
A first output power that has a laser light source and an attenuator that adjusts the output power of the laser beam from the laser light source, can generate plasma by converting the atmospheric gas into gas plasma, and an output smaller than the first output power A laser output optical system that switches and irradiates the second output power, which is power and capable of desorbing deposits when irradiated on the surface of the solid sample,
Arranged so as to face the surface of the solid sample at a position above the solid sample, the laser beam irradiated with the second output power is allowed to pass through and irradiate the solid sample, and detached from the surface of the solid sample A capture member that captures the deposit with a capture surface facing the solid surface;
The capture surface of the capture member can be held toward the solid surface, and the capture surface where the deposits are captured is reversed and held in a state directed toward the laser irradiation side. Possible capture member front and back reverse holding mechanism,
A spectrum measuring unit for measuring an emission spectrum of plasma generated by laser irradiation at the first output power in a state where the capturing surface where the deposits are captured is held facing the laser irradiation side. Characteristic deposit analyzer. The deposit analysis apparatus according to claim 1, wherein the capturing member is a window material capable of transmitting a laser beam having a second output power. 2. The deposit analyzer according to claim 1, wherein the capturing member is a metal mask formed with a slit through which a laser beam having a second output power passes or a mesh formed of a thin metal wire. The deposit analysis apparatus according to any one of claims 1 to 3, wherein the capturing member front / back reversing holding mechanism includes a rotation mechanism that rotates the capturing member.

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