JPH06194319A - Method and equipment for analyzing sample - Google Patents

Abstract

PURPOSE:To provide a method and equipment for analyzing a micro region, the composition, or the components of both organic and inorganic sample materials with high sensitivity and high resolution. CONSTITUTION:The analyzing equipment being applied to the work for analyzing the composition and the components of dust particles adhered to a wafer in the fabrication of semiconductor comprises a sample evaporation laser mechanism 2 for irradiating a test wafer 1 with an evaporation laser beam 16, a time-of-flight type mass spectrometer 3 for detecting and analyzing atoms, molecules, or ions 24 evaporated from the wafer 1, and an observation laser mechanism 4 for irradiating the wafer 1 with an observation laser beam 30 to form a scanning sample image. A micro portion is located accurately by the high resolution observing function using the observation laser beam 30 and the micro portion thus specified is irradiated with the evaporation laser beam 16 thus analyzing a dust particle 10 on the wafer 1 accurately and quickly.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sample analysis technique,
In particular, the present invention relates to a technique effectively applied to a sample analyzer and method capable of highly sensitive and high-resolution composition / component analysis in a minute area such as a semiconductor, a liquid crystal display, a memory disk, and a circuit board.

[0002]

2. Description of the Related Art For example, taking the semiconductor industry as an example, in semiconductor manufacturing, yield improvement, that is, eradication of manufacturing defects is the most important problem, and in order to eliminate this manufacturing defect, it is the largest cause of defects. It is important to reduce foreign matter adhering to the wafer.

The reduction of foreign matter adhering to the wafer is generally carried out through inspection, observation and analysis procedures. For example, foreign matter inspection is roughly divided into two contents: one is dust generation in process equipment and the level of wafer processing environment. The second one is to check foreign matter adhering to the wafer being manufactured.

In any of the inspection methods, a generally used method is to irradiate a laser beam as a probe onto the wafer surface and detect light scattered from foreign matter adhering to the wafer surface. By scanning the entire surface, presence / absence of foreign matter, size of foreign matter, position coordinates, etc. are detected for each location.

Then, the inspected wafer is transferred to a high-resolution observation device such as a scanning electron microscope or a laser microscope, and the appearance and shape of the detected foreign matter are observed at a high magnification. Furthermore, in the case where the foreign matter generation source cannot be identified only from the appearance and shape observation results, or in order to confirm the estimated generation source, the wafer is brought into an analyzer for composition / component analysis.

There are various methods for this component analysis. Among them, the most widely used means that analysis of a minute region is possible are the characteristic X-ray analysis of electron beam excitation and the fluorescence analysis of light beam excitation. Is.

For example, the characteristic X-ray analysis by electron beam excitation is mainly used for the analysis of inorganic foreign matters. The foreign matter is irradiated with a finely focused electron beam and emitted from the foreign matter portion excited by incident electrons. Characteristic X-rays are detected by an X-ray detector, and quantitative information is obtained from the component and intensity from the wavelength.

This X-ray detector is classified into an energy dispersive type and a wavelength dispersive type. In general, an energy dispersive type detector is used because it is inferior in wavelength resolution but simple and highly sensitive. .

On the other hand, for organic foreign matters, fluorescence spectroscopy is used. This is a method of irradiating and exciting the foreign matters with visible or ultraviolet light as a probe, and determining the wavelength of fluorescence emitted from the foreign matters to determine the composition. Is.

[0010]

However, in the prior art as described above, the characteristic X-ray analysis of electron beam excitation and the fluorescence analysis of light beam excitation are performed in the direction in which the semiconductor device should proceed, that is, high speed and high integration. It is becoming difficult to apply it to the miniaturization of the pattern for realizing the above direction.

That is, as the pattern becomes thinner, the size of the foreign matter in question becomes smaller, and in order to respond to such a trend of progress, the sensitivity of foreign matter detection in the foreign matter inspection is being improved, and at present, Although it is possible to detect a foreign substance of about 0.1 μmφ, it cannot be said that the means for analyzing the composition / component of the detected minute foreign substance is sufficient.

Therefore, none of the above-mentioned methods has sufficient sensitivity and resolution for detecting a minute amount of foreign matter component, and the analysis region is not subjected to characteristic X-ray analysis by electron beam excitation. The current practical limit is 0.5 μmφ and about 2 μmφ for light beam excitation fluorescence analysis.

Further, in the electron beam excitation, the analysis target is restricted to the conductive material, which is because the irradiation position of the electron beam incident on the insulator sample due to charging is shifted during the analysis, and the organic sample is also used. In the fluorescence analysis targeting 1), there is a problem that the fading progresses during the analysis due to the alteration caused by the light beam irradiation.

Therefore, an object of the present invention is to provide a sample analyzer and method capable of analyzing the composition and components of a minute region with high sensitivity and high resolution regardless of whether the sample material is organic or inorganic. It is in.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0016]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the sample analyzer of the present invention is a sample analyzer for irradiating a sample with a laser beam for sample vaporization and detecting and analyzing atoms, molecules or ions vaporized from the irradiated sample portion. The laser light for observation is provided coaxially with the laser light for vaporizing the sample to irradiate the sample to form a scanning sample image.

In this case, there is provided positioning means for positioning the analysis site based on the scanning sample image formed by the irradiation of the observation laser beam.

Further, the analysis section for detecting and analyzing the ions vaporized by the irradiation of the sample vaporizing laser beam is a mass spectrometer capable of simultaneous multi-element analysis.

The sample analysis method of the present invention is a sample analysis method in which a sample is irradiated with a laser beam for sample vaporization, and atoms or molecules / ions vaporized from the irradiated sample portion are detected and analyzed. The observation laser beam forming the sample image of the sample is irradiated onto the sample coaxially with the sample vaporization laser beam to form a scanning sample image, and the position of the analysis point is determined based on the scanning sample image. A laser beam for vaporizing a sample is applied to this analysis location for analysis.

In this case, the identification information of the sample is read, and a corresponding work instruction is read based on the read identification information.
Based on the first processing procedure for specifying work conditions / work data and the specified work instructions / work conditions / work data,
Between a second processing procedure for automatically performing a specified location and work for a specified sample, a third processing procedure for simultaneously displaying a plurality of data / images necessary for analysis, and an external device The fourth processing procedure for online transfer and input / output of work instructions, work conditions, work data, image data, and analysis data information necessary for analysis, and alignment and / or positioning of the laser beam and the sample. A fifth processing procedure to be performed, and a sixth processing procedure for automatically analyzing a single or a plurality of locations in the sample for the designated sample, and a sixth processing procedure for a single or a plurality of locations in the sample for the designated sample. 7th processing procedure of comparing analysis data with pre-stored reference data and analysis, and display processing result of analysis data, image data and / or analysis data as required Among the processing procedures of the eighth processing procedure for storing or outputting, it is performed at least one processing procedure.

[0022]

According to the above-described sample analyzing apparatus and method, in addition to the sample vaporizing laser light, the observation laser light and the positioning means are provided, and the first to eighth processing procedures are performed as necessary. By executing the above, the precise positioning of the minute part is realized by the positioning means based on the high-resolution observation function of the observation laser beam, and the specified minute part is irradiated with the laser beam for sample vaporization. However, the sample can be analyzed accurately and quickly.

In this case, since the mass spectrometer is used in the vaporized ion analyzer, the multielement simultaneous analysis can be performed by the mass spectrometer such as the time-of-flight mass spectrometer, so that the minute portion of the sample can be analyzed. Can be analyzed with high sensitivity and high resolution.

That is, there is a possibility that a minute region can be analyzed with high sensitivity and high resolution without the problems of conventional charging of an insulator sample by a charged particle beam such as an electron beam and fading of an organic substance during photoexcitation. Ionization Microprobe Analysis (LIMA) or Laser Ionization Mass Spectrometry (LAM)
This is made possible by adding an accurate positioning function for minute portions in the sample to the (MA) method.

Therefore, in the conventional apparatus and method, since there is no concept of analyzing a submicron minute region or a minute object in a specific portion of the sample, the observation function used for positioning does not have sufficient image resolution. In addition, the positioning function is insufficient, and it was not possible to irradiate the target laser beam with the vaporizing laser light. Can be specified.

This makes it possible to irradiate a desired analysis portion with a laser beam for vaporizing a sample accurately and quickly, and to perform composition / component analysis of a minute region with high sensitivity and high resolution regardless of whether it is an organic substance or an inorganic substance. You can

[0027]

EXAMPLE FIG. 1 is a schematic configuration diagram showing a sample analyzer which is an example of the present invention, FIG. 2 is a work flow chart of the composition / component analysis of foreign substances in the sample analyzer of this example, and FIG. 3 is a book. In the embodiment, an explanatory view showing a movement of a field of view for finding an analysis portion, and FIG. 4 are explanatory views of a beam diaphragm using phase inversion for obtaining a narrow laser beam.

First, the configuration of the sample analyzer of this embodiment will be described with reference to FIG.

The sample analyzer of the present embodiment is applied to, for example, a composition / component analysis work of a foreign substance adhered to a wafer in semiconductor manufacturing, and is a foreign substance component analyzing device using a time-of-flight mass spectrometry method of laser light excitation. , A sample vaporization laser mechanism 2 for irradiating a wafer (sample) 1 to be tested with a vaporization laser beam, and a time-of-flight mass for detecting and analyzing atoms, molecules, or ions vaporized from the irradiated wafer 1. It comprises an analyzer 3 and an observation laser mechanism 4 which irradiates the wafer 1 with the observation laser light coaxially with the vaporization laser light to form a scanning sample image.

The wafer 1 is identified by the optical character reader 6 in the loading chamber 5, is loaded on the sample stage 9 in the vacuum container 8 by opening and closing the valve 7, and is unloaded again in the loading chamber 5 after the test. Loaded. The loading / unloading of the wafers 1 into / from the loading chamber 5 is carried out one by one from a wafer carrier (not shown) and inserted or discharged. Further, the sample stage 9 is scanned in the X direction and the Y direction by a drive mechanism (positioning device) not shown, and the position of the analysis site to which the foreign matter 10 is attached is specified.

The sample vaporizing laser mechanism 2 includes a sample vaporizing laser 11, a switching mirror 12, an optical deflector 13, and a mirror 14.
And vaporizing laser light 1 such as a pulse emitted from the sample vaporizing laser 11
6 is switched by the switching mirror 12 to the laser light from the observing laser mechanism 4, and the optical deflector 13 is driven by a driving mechanism (positioning means) (not shown) to move 1 in the X direction.
Dimensionally scanned and mirror 14 and objective lens 15
It is irradiated onto the wafer 1 via the.

The time-of-flight mass spectrometer 3 is composed of an ion extraction electrode 17, a flight space 18, a reflection electrode 19, a post acceleration electrode 20, an ion detector 21, a pulse amplifier 22 and an oscilloscope 23, and vaporizes from the wafer 1. The generated ions 24 fly in the flight space 18 and are repelled by the reflection electrode 19, and the post acceleration electrode 20.
And is detected by the ion detector 21. Then, the detection signal of the ion detector 21 is amplified by the pulse amplifier 22, and the composition / component of the foreign matter is analyzed by the mass spectrum displayed on the oscilloscope 23, enabling simultaneous multi-element analysis.

The observation laser mechanism 4 includes an observation laser 25.
And a switching mirror 12 common to the sample vaporization laser mechanism 2,
The observation laser light 30 emitted from the observation laser 25 is composed of an optical deflector 13, a mirror 14, an objective lens 15, a pinhole 26, a photodetector 27, a signal amplifier / processor 28, a display 29, and the like. , Switching mirror 12, optical deflector 13, mirror 14 and objective lens 15
It is irradiated onto the wafer 1 via the. Then, the reflected light 31 from the wafer 1 passes through the objective lens 15 and the mirror 14 and a sample image is detected by the photodetector 27 in a point shape by the pinhole 26, and this image signal is amplified by the signal amplifier / processor 2
It is displayed on the display 29 after being amplified and processed by 8.

The two-dimensional scanning for forming the sample image is performed by combining the X-direction scanning of the optical deflector 13 and the Y-direction scanning of the sample stage 9.

Next, the operation of the present embodiment will be described with reference to FIG. 2 for the work flow of composition / component analysis.

First, after undergoing an inspection with a foreign matter inspection device and an image observation with a scanning electron microscope (SEM), the wafer 1
The wafer carrier containing is set in this analyzer. At this time, the in-wafer position coordinates of the foreign substance 10 relating to the wafer 1 taken by another device, the size of the foreign substance 10,
Alternatively, information such as image data of the foreign matter 10 is also input to the analyzer and stored in the memory. This information is input online through the LAN to which each device is connected (step 201).

Further, the wafers 1 are inserted one by one into the loading chamber 5 from the set wafer carrier. At this time, in parallel with the evacuation of the loading chamber 5, the wafer number formed on the wafer 1 is identified by the optical character reader 6, and the work instruction, work condition, and foreign matter position coordinate corresponding to this wafer 1 are identified. Data is transferred to the working memory. This data is used for the subsequent analysis work (steps 202 and 203).

When the evacuation of the loading chamber 5 is completed, the valve 7 is opened and the wafer 1 is loaded on the sample stage 9. After this loading is completed and the valve 7 is closed again, the next wafer 1 is prepared in the loading chamber 5 in parallel with the subsequent analysis processing of the wafer 1 (step 204).

After that, in the wafer 1 loaded on the sample stage 9, first, in order to perform the alignment of the wafer 1, the alignment laser beam 30 from the observation laser 25 is used to detect the alignment pattern or the outline of the wafer 1. The shape is detected. The detection of this alignment pattern is performed by a method according to the alignment method of an exposure apparatus used for pattern exposure on a semiconductor.

That is, an observation laser beam 30 is applied to an alignment pattern which has been processed on the wafer 1 in advance, and reflected light 31 from the alignment pattern is detected by a photodetector 27 such as a photomultiplier tube or a semiconductor diode. Then
The position coordinate of the alignment pattern on the analyzer is detected from the moving position of the sample stage 9 at the time of detection.

The detected position coordinates obtained from the plurality of alignment patterns serve as a reference for positioning the foreign matter 10 attached on the wafer 1. Wafer 1
The design position coordinate data of the processed alignment pattern is stored in advance in the working memory as a part of the above-mentioned information about the wafer 1, and is used for rough positioning when detecting the alignment pattern.

Further, the method of detecting the contour shape of the wafer 1 is used when the wafer 1 does not have a positioning mark corresponding to the alignment pattern. For this, a means conforming to the method used for wafer pre-alignment in the exposure apparatus is used. For example, the observation laser light 3
The contour shape of the wafer 1 is detected by irradiating the outer peripheral portion of the wafer 1 with 0 and detecting the reflected light 31 from the wafer edge.

Then, similarly to the alignment pattern detection method, the obtained contour shape is used as a reference when positioning the foreign matter 10. Similarly, the information about the shape of the wafer 1 is stored in the working memory in advance, and is used to easily perform the contour shape detection operation (steps 205 and 206).

Subsequently, using the reference of the position coordinates obtained as described above, the target movement amount of the sample stage 9 is determined so that the foreign substance 10 to be analyzed is placed at the irradiation position of the observation laser beam 30. To be Based on this value, the sample stage 9
When is moved to the target position, the observation laser light 30 is irradiated, and the two-dimensional scanning sample image of this region is obtained by detecting the reflected light 31 from the irradiation position. Then, the image signal is amplified and processed by the signal amplifier / processor 28, and the sample image is displayed on the display 29.

At this time, the two-dimensional scanning is performed by the observation laser beam 30.
May be two-dimensionally scanned, or the sample stage 9 may be two-dimensionally scanned. In this embodiment, in order to achieve both high-speed scanning and simplicity of the optical system, the observation laser light 30 is scanned in the X direction by the optical deflector 13 such as a galvanometer mirror or an acousto-optic device, and the sample stage 9 is operated in the Y direction. The method of scanning in the direction is adopted.

In this embodiment, a method similar to the confocal laser scanning microscope is used to obtain a clear image or a three-dimensional image for the purpose of facilitating finding and positioning of the foreign matter 10. Is taking. That is, by arranging the pinhole 26 on the front surface of the photodetector 27 to form a point detector, the structure in which the point light source of the observation laser light 30 and the point detector have a conjugate positional relationship with the objective lens 15. I am collecting.

Although not shown in the figure, in order to obtain a three-dimensional image, a function of changing the focal position by a driving mechanism of the sample stage 9 in the Z direction and the like to take a plurality of sample images,
It has an image memory for adding a plurality of sample images (step 207).

Further, the foreign matter 10 to be analyzed is found from the sample image obtained as described above, and the sample stage 9 is finely moved so that the foreign matter 10 is located at the center of the visual field of the sample image.
At this time, a mark such as a cross may be attached to the center of the visual field on the display 29 in advance. Alternatively, it is possible to automatically move the image of the visual field portion taken by another device to the center of the visual field as a template (step 20).
8).

The position coordinates of the sample stage 9 when the image of the foreign matter 10 comes to the center of the field of view correct the target movement amount of the sample stage 9 with respect to the foreign matter 10 to be analyzed thereafter to a more accurate value. This is fed back to the calculation result of the stage target movement amount described above. Further, when the target foreign substance 10 cannot be found in the first visual field, the operation is facilitated by having a function of automatically changing the visual field as shown in FIG.

Since the observation magnification of the sample image depends on the target size of the foreign matter 10, it is preferable to have a function of changing the observation magnification for each foreign matter 10 or each wafer 1.
Further, the observation magnification for each foreign matter 10 is changed based on the size information of the foreign matter 10 sent from the foreign matter inspection device or the SEM.

Generally, in order to find the foreign matter 10,
I want a foreign object image of at least 1.5 mm or more on the display 29. If the target foreign material 10 has a size of 0.3 μ
If mφ, an observation magnification of about 5000 times is required. The observation magnification is changed by changing the scanning width of the observation laser beam 30 and the sample stage 9.

Further, in order to easily find the foreign material 10, it is preferable that the image data and reference information of the foreign material 10 taken by the foreign material inspection device or the SEM are displayed simultaneously with the sample image. This SEM image or the like may be displayed on the same display 29 as the sample image, or may be displayed on another display 2.
9 may be displayed.

Furthermore, when observing a sample having a low image contrast such as a mirror-finished wafer, it may not be clear whether the sample image is in focus or not, and it may be difficult to find the minute foreign matter 10. In order to eliminate such inconvenience, it is essential to have an automatic focusing function.

In this embodiment, focusing is performed by using a pinhole 26 and a point detector composed of a photodetector 27. That is, the reflected light 31 from the mirror surface wafer or the like when the observation laser light 30 is irradiated is detected, and the sample image is formed with the height of the wafer 1 at which the output of the photodetector 27 is maximized as the in-focus position. . Note that a dedicated focusing mechanism may be provided independently of the image detection optical system. At this time, the focusing means is not limited to the optical focusing method, and a focusing means such as a capacitance method can be used (step 209).

Subsequently, when the work of finding the foreign substance image and moving to the center of the visual field is completed, the work of analyzing the foreign substance 10 is started. First, the deflection operation of the optical deflector 13 is stopped so that the irradiation position of the observation laser light 30 coincides with the center of the visual field.
The direction of the switching mirror 12 is switched and the observation laser light 30
Instead, the wafer 1 is irradiated with the vaporizing laser light 16 such as a pulse emitted from the sample vaporizing laser 11.

At this time, the laser light irradiation optical system including the switching mirror 12, the mirror 14, and the objective lens 15 has the same optical axis for the observation laser light 30 and the vaporization laser light 16, and the vaporization laser. The light 16 is accurately emitted at the focal point on the foreign material 10.

In this embodiment, the chromatic aberration correction optical system for correcting the chromatic aberration of the observation laser light 30 and the vaporization laser light 16 is omitted. Further, it is desirable to select lasers having substantially the same wavelength as these laser lights. As a specific selection example, for example, the observation laser 25 may be an Ar laser.
The laser has a wavelength of 515 nm, and the sample vaporizing laser 11 uses the first harmonic of a YAG laser having a wavelength of 532 nm.
By using such a laser having almost the same wavelength, the laser irradiation optical system can be greatly simplified.

Although the pulse width of the YAG laser is one of the factors that determine the mass resolution, it is set to about 10 ns. Further, when the YAG laser light is irradiated, the photodetector 27 that may be damaged by the laser scattered light.
It is advisable to prevent the laser scattered light from directly entering by, for example, shifting the optical axis or protecting with a shutter.

Further, the foreign matter portion irradiated with the vaporizing laser beam 16 is vaporized, and atoms, molecules, positive / negative ions, etc. are evaporated. Of these, only the positive or negative ions 24 are drawn into the flight space 18 by the electrostatic field created by the ion extracting electrode 17. Then, the ions 24 flying in a straight line at a constant speed in the flight space 18 are repelled by the reflection electrode 19, folded back and detected by the ion detector 21 using a secondary electron multiplier or a photomultiplier.

At this time, the time for the ions 24 to fly in the flight space 18 is proportional to the square root of the mass of the ions 24. Therefore, the ions 24 reach the ion detector 21 in order of increasing mass, with the time point of irradiation of the vaporizing laser beam 16 as the starting point of the time axis. Then, the detection signal of the ion detector 21 is amplified by the pulse amplifier 22 and displayed on the oscilloscope 23 to obtain the mass spectrum of the vaporized foreign matter portion.

As a concrete example, when detecting the vaporized negative ions 24, for example, the ion extraction electrode 1 is used.
When a voltage of 1000 V is applied to 7, a negative voltage higher than that is applied to the reflective electrode 19.

At this time, the voltage application to the ion extracting electrode 17 is synchronized with the irradiation of the vaporizing laser beam 16, and a pulse voltage of several tens ns, which has a longer pulse width than that, is applied. By doing this, unnecessary ions 24 in the atmosphere
Can be reduced, and the background noise of the detection signal can be reduced.

In terms of reducing background noise, it is preferable to maintain the inside of the vacuum container 8 as high vacuum as possible. Particularly, it is desirable that the space from the passage of the vaporizing laser beam 16 to the sample surface of the wafer 1 and the draft space have a vacuum degree of 10 ⁻⁶ Pa or more.

Further, in order to increase the sensitivity, an ionization laser 32 as shown in FIG. 1 for ionizing vaporized neutral atoms / molecules in synchronization with the irradiation of the vaporization laser beam 16 is used. Laser light for ionization 33 such as pulse
Is converged by a converging lens 34 and is irradiated in the vicinity of the surface of the wafer 1 and in the parallel direction. This pulse width is 16 V
Take a little wider than.

The ionization laser 32 of the ionization laser light 33 is an ArF excimer laser with a wavelength of 193n.
m or a dye laser is used. An electron gun may be used instead of the ionization laser 32, and a flood electron beam may be used to increase the ionization rate. Further, in order to avoid a decrease in the sensitivity of the ion detector 21 in the high mass portion, the post acceleration electrode 20 is arranged immediately before the ion detector 21 as shown in FIG. 1 to accelerate the ions 24 incident on the ion detector 21. You may do it.

In the analysis, the vaporizing laser beam 16 is used.
If the irradiation energy density of the
Not only 0 but also the base portion is vaporized, and the background noise of the obtained mass spectrum is increased. In order not to cause such an inconvenience, it is preferable to have a function of repeatedly irradiating with the vaporizing laser beam 16 having a relatively low energy density and integrating the obtained mass spectrum data of each vaporizing pulse.

The integrating section has a memory function so that the mass spectrum data for each vaporizing pulse can be selectively integrated. Thus, for example, while observing the change state of the mass spectrum data, if the influence of the background appears on the data, the subsequent data can be excluded.

Depending on the sample, either positive or negative ions 24 may be preferentially generated. Therefore, the ion extraction electrode 17 and the reflection electrode 1
It is advisable that the applied voltages of the 9, the post-accelerating electrode 20, the ion detector 21 and the like can be switched between positive and negative and can be used properly depending on the case.

Further, in order to facilitate the analysis of the obtained mass spectrum, the mass spectrum of the substance having a high frequency of occurrence is held as a library, which is arbitrarily read out, and the obtained mass spectrum is displayed on the same display 29. It is advisable to have a function to display and compare simultaneously (step 210).

When the analysis of one foreign substance 10 is completed as described above, the sample stage 9 moves to the next foreign substance position in the wafer 1, and the component analysis of this foreign substance 10 is similarly performed. When the analysis work of the wafer 1 is completed in this way, the next wafer 1 is processed in the same procedure (steps 211 to 213).

The analysis data, image data, position coordinate data, etc. obtained from the results of the analysis work are stored in a file in the analysis device, and are displayed or output on the display 29 and output to an external device as required. Is used for online transfer of data (steps 214 and 215).

As the foreign matter 10 is vaporized, scattered matter adheres to and contaminates the vicinity of the wafer 1. In particular, in the optical parts including the objective lens 15, deterioration of optical characteristics such as transmittance and reflectance becomes a problem due to progress of contamination.

For this reason, the optical parts are arranged outside the vacuum as much as possible, and the objective lens 15 exposed to scattered objects is also used.
In order to facilitate the cleaning of (1), it is recommended that the optical system unit can be easily attached and removed with one touch.

It is also possible to automate the alignment of the wafer 1, positioning of the analysis location, analysis, collation with reference data, and the like.

Therefore, according to the sample analyzer of the present embodiment, the observation laser 25, the photodetector 27, the signal amplifying / signal amplifying / detecting device 27 are provided in the sample vaporizing laser mechanism 2 and the time-of-flight mass spectrometer 3.
By adding the observation laser mechanism 4 including the processor 28 and the display 29, the observation laser light 3
Accurate positioning of a minute portion based on the high resolution observation function by 0 and irradiating the specified minute portion with the vaporizing laser beam 16 enables accurate and quick analysis of the foreign matter 10 on the wafer 1. Can be done.

Moreover, by using the time-of-flight mass spectrometer 3 in the analysis section for the vaporized ions 24, simultaneous multi-element analysis becomes possible, and minute portions of the wafer 1 are analyzed with high sensitivity and high resolution. be able to.

In this case, steps 202 and 203
Processing corresponds to the first processing procedure, and step 202
The second processing procedure and the third processing procedure in step 210 are respectively executed by the instruction. Further, steps 215 and 216 correspond to the fourth processing procedure, and steps 207 to 209 are the fifth processing procedure, step 20.
The sixth processing procedure is executed by repeating steps 7 to 211. Then, in step 210, the seventh processing procedure which is a feature of the present invention is executed, and the result is step 21.
It is output by the eighth processing procedure of No. 4,215.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, with respect to the sample analyzer of this embodiment, the case where the incident direction of the vaporizing laser beam 16 and the extracting direction of the ions 24 are different has been described, but the present invention is not limited to the above embodiments. It is also applicable to a structure in which the incident axis of the vaporizing laser light and the extraction axis of the ions are made coaxial, and in this case also, the sample stage is used when it has a tilting function as shown in this embodiment. easy.

The sample analyzer of the present embodiment can be modified in various ways as described below.

(1). The point analysis is shown in which the vaporizing laser beam 16 is applied to only one point to obtain a mass spectrum. One-dimensional or two-dimensional scanning is performed by moving the sample stage for each pulse. It is also possible to take two-dimensional information and two-dimensional information / images.

(2). Laser light for observation and vaporization 30, 1
Although the case where 6 is deflected by the optical deflector 13 by one stage is shown, it is also possible to deflect plural stages by using a plurality of optical deflectors when largely deflecting.

(3) Although not mentioned in this embodiment, in order to make a thinner laser beam, a phase inversion part is provided around the aperture part of the laser optical path as shown in FIGS. 4 (b) and 4 (C). The effective range L of the amplitude distribution of the conventional method shown in FIG. 4 (a) can be narrowed to the effective ranges L1 and L2.

(4). Although the vertical reflected light 31 is used as an image signal, it may be scattered light, or other information such as fluorescence, Raman light, or a photoexcitation current may be used as an image signal.

(5). Although the analysis method using the time-of-flight mass spectrometer 3 was used, other analysis methods such as a method using ECR by a magnetic field may be used.

Further, the sample analyzer of the present embodiment has been shown to be applied to the analysis of the foreign matter 10 adhering to the wafer 1 in the semiconductor manufacturing, but in addition to this, the surface contamination of the wafer and the composition of the CVD / sputtered film are shown. It can also be applied to high-resolution and high-sensitivity analysis, or resist and etching at the pattern processing stage, residue analysis such as hole bottoms, etc. In such a case, mapping display on the wafer is also possible.

In the above description, the case where the invention mainly made by the present inventor is applied to the sample analyzer used in the semiconductor manufacturing which is the field of application of the invention has been described, but the invention is not limited to this and the liquid crystal display is not limited thereto. It is also widely applicable to all fields in which high sensitivity analysis of minute areas such as memory disks and circuit boards is required.

[0088]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, the observation laser light is irradiated onto the sample coaxially with the sample vaporization laser light to form a scanning sample image,
By locating the analysis point based on this scanning sample image, it is possible to irradiate the analysis point with laser light for sample vaporization and perform analysis. It is possible to accurately position a minute portion, and to accurately and promptly analyze the composition and component of the sample by the laser beam for sample vaporization.

In particular, by using a mass spectrometer as the analysis section for detecting and analyzing the ions vaporized by the irradiation of the laser beam for vaporizing the sample, simultaneous multi-element analysis becomes possible.
It is possible to analyze minute parts of a sample with high sensitivity and high resolution.

As a result, it is possible to irradiate the desired minute analysis portion with the vaporizing laser light accurately and quickly.
It is possible to obtain a sample analyzer and method capable of highly sensitive and high-resolution analysis of a minute region or an object regardless of whether it is an organic substance or an inorganic substance as a sample material.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a sample analyzer which is an embodiment of the present invention.

FIG. 2 shows the composition of foreign matter in the sample analyzer of this example.
It is a work flow diagram of component analysis.

FIG. 3 is an explanatory diagram showing a visual field movement for finding an analysis portion in the present embodiment.

FIG. 4 is an explanatory diagram of a beam diaphragm using phase inversion for obtaining a narrow laser beam in the present embodiment.

[Explanation of symbols]

 1 wafer (sample) 2 sample vaporization laser mechanism 3 time-of-flight mass spectrometer 4 observation laser mechanism 5 loading chamber 6 optical character reader 7 valve 8 vacuum container 9 sample stage 10 foreign matter 11 sample vaporization laser 12 switching mirror 13 Optical Deflector 14 Mirror 15 Objective Lens 16 Vaporization Laser Light 17 Ion Extraction Electrode 18 Flight Space 19 Reflection Electrode 20 Post Accelerator Electrode 21 Ion Detector 22 Pulse Amplifier 23 Oscilloscope 24 Ion 25 Observation Laser 26 Pinhole 27 Photodetector 28 Signal Amplifier / Processor 29 Display 30 Laser Light for Observation 31 Reflected Light 32 Laser for Ionization 33 Laser Light for Ionization 34 Convergent Lens

Claims (5)

[Claims] 1. A sample analyzer for irradiating a sample with laser light for vaporizing a sample, and detecting and analyzing atoms, molecules, or ions vaporized from the irradiated sample portion, wherein the laser light for vaporizing the sample is used. A sample analyzer which coaxially has an observation laser beam for irradiating the sample to form a scanning sample image. 2. The sample analyzer according to claim 1, further comprising positioning means for positioning an analysis location based on a scanning sample image formed by irradiation of the observation laser beam. 3. The mass spectrometer capable of simultaneous multi-element analysis, wherein the analysis unit for detecting and analyzing the ions vaporized by the irradiation of the laser beam for vaporizing the sample is a mass spectrometer. The sample analyzer described. 4. A sample analysis method of irradiating a sample with laser light for vaporizing a sample, and detecting and analyzing atoms, molecules, or ions vaporized from the irradiated sample portion to form a sample image of the sample. An observation laser beam to irradiate the sample coaxially with the sample vaporization laser beam to form a scanning sample image,
A sample analysis method characterized in that an analysis site is positioned based on the scanned sample image, and the analysis site is irradiated with the sample vaporizing laser beam for analysis. 5. The identification information of the sample is read, and a corresponding work instruction / work condition / operation is performed based on the read identification information.
A first processing procedure for designating work data, and a second processing procedure for automatically carrying out a designated location and work for a designated sample based on designated work instructions, work conditions, and work data. And multiple data required for analysis.
Between the third processing procedure that displays images simultaneously and the external device, work instructions, work conditions, work data, etc. necessary for analysis.
Regarding the fourth processing procedure of transferring and inputting / outputting image data / analysis data information online, the fifth processing procedure of aligning and / or positioning the laser beam and the sample, and the designated sample, A sixth processing procedure for automatically analyzing a single or a plurality of points in a sample, and collating the analytical data of a single or a plurality of points in the sample with reference data stored in advance for the designated sample. At least one of the seventh processing procedure of analyzing and analyzing and the eighth processing procedure of displaying / storing or outputting the processing result of the analysis data, the image data and / or the analysis data as necessary. The sample analysis method according to claim 4, wherein one processing procedure is performed.