Analysis device and analysis method

Abstract

An analysis device according to the present invention comprises analysis equipment, a first laser light source, a first slit, a first detector, and a stage. The analysis equipment analyzes a sample. The first laser light source emits laser light. The first slit allows laser light which is emitted from the first laser light source and reflected by the surface of the sample to pass therethrough when the distance between the sample and the analysis equipment is a prescribed distance, and blocks the laser light, which is emitted from the first laser light source and reflected by the surface of the sample, when the distance between the sample and the analysis equipment differs from the prescribed distance. The first detector detects the laser light which has passed through the first slit. The stage, on which the sample is placed, is movable in a first direction toward or away from the analysis equipment.

Description

Analytical device and analytical method

[0001] The present invention relates to an analysis device and an analysis method for analyzing the surface of an object.

[0002] X-ray photoelectron spectroscopy (XPS) requires that the analyzer and sample be precisely aligned to a predetermined relative position before analysis can begin. Conventional alignment methods include determining the position based on the intensity of the XPS signal (the XPS signal intensity is maximized when the sample is optimally positioned), irradiating the sample surface with a scanned electron beam and observing the secondary electron image emitted from the irradiated surface, using an optical microscope image adjusted to focus on the sample at a predetermined relative position, and observing the irradiation point of a laser light source adjusted to focus on the sample at a predetermined relative position (see, for example, Patent Documents 1 to 4).

[0003] JP 10-246712, JP 52-077792, JP 03-026948, JP 07-183343

[0004] However, alignment methods using XPS signal intensity as a judgment criterion require time to identify relative positions. Furthermore, alignment methods using optical or secondary electron images may require human judgment. Image recognition and other methods can be used to automate the process and reduce the time required. However, this method has uncertainties, such as the inability to identify the surface of a large number of unspecified, diverse samples.

[0005] In view of the above circumstances, an object of the present invention is to provide an analytical device and an analytical method that are capable of quickly and accurately aligning an analytical instrument with a sample.

[0006] To achieve the above object, an analytical device according to one embodiment of the present invention includes an analytical instrument, a first laser light source, a first slit, a first detector, and a stage. The analytical instrument analyzes a sample. The first laser light source emits laser light. The first slit passes laser light emitted from the first laser light source and reflected by the surface of the sample when the distance between the sample and the analytical instrument is a predetermined distance, and blocks laser light emitted from the first laser light source and reflected by the surface of the sample when the distance between the sample and the analytical instrument is different from the predetermined distance. The first detector detects the laser light that has passed through the first slit. The sample is placed on the stage, which is movable in a first direction that moves toward or away from the analytical instrument.

[0007] The analytical device may further include: a second laser light source that emits laser light; a second slit that allows the laser light emitted from the second laser light source and reflected by the surface of the sample to pass when the sample and the analytical instrument are at the specified distance, and blocks the laser light emitted from the second laser light source and reflected by the surface of the sample when the distance between the sample and the analytical instrument is different from the specified distance; and a second detector that detects the laser light that has passed through the second slit.

[0008] When the sample and the analytical instrument are spaced apart by the predetermined distance, the laser light emitted from the first laser light source and the laser light emitted from the second laser light source may be incident on the same position on the surface of the sample.

[0009] When viewed from the first direction, the optical axis of the first laser light source and the optical axis of the second laser light source may be perpendicular to each other.

[0010] The analytical apparatus may further include a drive mechanism that moves the stage in the first direction to change the distance between the sample and the analytical instrument, and a control unit that controls the drive mechanism based on an output of the first detector.

[0011] The control unit may stop the movement of the stage when the output of the first detector exceeds a threshold value.

[0012] The analytical apparatus may further include a drive mechanism that moves the stage in the first direction to change the distance between the sample and the analytical instrument, and a control unit that controls the drive mechanism based on outputs of the first detector and the second detector.

[0013] The control unit may stop the movement of the stage when an output from either the first detector or the second detector exceeds a threshold value.

[0014] The first slit, the first detector, the second slit, the second detector, and the stage may be arranged in a vacuum chamber, and the first laser light source and the second laser light source may be arranged outside the vacuum chamber.

[0015] The first detector and the second detector may be PSDs (Position Sensitive Detectors).

[0016] The analytical instrument may be an instrument that performs X-ray photoelectron spectroscopy.

[0017] In order to achieve the above object, an analytical method according to one embodiment of the present invention includes placing a sample on a mounting surface of a stage, moving the stage in a first direction that is a direction toward or away from the analytical instrument, irradiating laser light from a first laser light source onto the surface of the sample, and when the sample and the analytical instrument are at a predetermined distance, allowing the laser light emitted from the first laser light source and reflected by the surface of the sample to pass, and when the distance between the sample and the analytical instrument is different from the predetermined distance, controlling the position of the stage using the output of a first detector that detects the laser light emitted from the first laser light source and passed through a first slit that blocks the laser light reflected by the surface of the sample.

[0018] As described above, the present invention can provide an analytical device and an analytical method that can quickly and accurately align an analytical instrument with a sample.

[0019] 1 is a schematic diagram of an analytical device according to an embodiment of the present invention; FIG. 2 is a schematic diagram showing the operation of the analytical device during analysis; FIG. 3 is a schematic diagram showing the distance between a sample and an analytical instrument in the analytical device; FIG. 4 is a schematic diagram showing the operation of the analytical device during alignment; FIG. 5 is a schematic diagram showing the arrangement of laser light sources of the analytical device; FIG. 6 is a schematic diagram showing the arrangement of laser light sources of the analytical device; FIG. 7 is a schematic diagram showing the operation of the analytical device during alignment.

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] [Configuration of the Analysis Apparatus] The analysis apparatus according to this embodiment will be described. Fig. 1 is a schematic diagram of an analysis apparatus 100 according to this embodiment. The analysis apparatus 100 is an apparatus that performs X-ray photoelectron spectroscopy (XPS).

[0022] 1, the analytical device 100 includes a vacuum chamber 101, an excitation radiation source 102, an analytical instrument 103, a stage 104, a first laser light source 105, a first slit 106, a first detector 107, a second laser light source 108, a second slit 109, a second detector 110, and a control unit 111. A sample S is placed in the vacuum chamber 101. The sample S preferably has a mirror-like surface, such as a silicon wafer.

[0023] The vacuum chamber 101 is connected to a vacuum exhaust means (not shown) and maintains the interior in a vacuum environment. The vacuum chamber 101 is provided with windows 121 and 122 that transmit laser light. The excitation radiation source 102 is disposed within the vacuum chamber 101 and irradiates the sample S with X-rays (in the figure, "X-ray"). FIG. 2 is a schematic diagram of the sample S being irradiated with X-rays. As shown in the figure, X-rays are irradiated from the excitation radiation source 102 onto a partial region of the surface of the sample S. Hereinafter, the region of the surface of the sample S that is irradiated with X-rays will be referred to as the analysis target region R. By irradiating the X-rays, electrons (in FIG. 2, "e － ") is released.

[0024] The analytical instrument 103 measures electrons (in FIG. 1, "e －Specifically, the analytical instrument 103 includes an electron lens unit 131 and an electron spectrometer unit 132. Electrons emitted from the analysis target region R are incident on the electron lens unit 131, separated into orbits according to the kinetic energy by the electron spectrometer unit 132, and detected by a detector (not shown).

[0025] The stage 104 is placed in the vacuum chamber 101, and the sample S is placed thereon. The stage 104 is configured to be movable by a drive mechanism (not shown) at least in a direction toward or away from the analytical instrument 103. Hereinafter, this direction will be referred to as the Z direction. Furthermore, it is more preferable that the stage 104 be a multi-axis stage that is movable in each direction. The distance between the sample S and the analytical instrument 103 is adjusted by moving the stage 104 in the Z direction. FIG. 3 is a schematic diagram showing the distance D between the sample S and the analytical instrument 103.

[0026] When analyzing the sample S using the analytical instrument 103, it is necessary to set the distance D to a specific distance suitable for the analysis and to precisely align the relative positions of the sample S and the analytical instrument 103. Hereinafter, this predetermined distance will be referred to as the "analysis distance." The analysis distance can be determined in advance by performing an analysis while changing the distance D.

[0027] The first laser light source 105 irradiates the surface of the sample S with laser light. FIG. 4 is a schematic diagram of the laser light in the analysis device 100. As shown in the figure, the first laser light source 105 is disposed outside the vacuum chamber 101, and the laser light L1 emitted from the first laser light source 105 enters the inside of the vacuum chamber 101 through a window 121 and is incident on the surface of the sample S. Hereinafter, the position at which the laser light L1 is incident on the surface of the sample S will be referred to as position P. The first laser light source 105 is configured so that when the distance D (see FIG. 3) is the analysis distance, the spot diameter of the laser light L1 on the surface of the sample S is 50 μm or less.

[0028] The first slit 106 is disposed in the vacuum chamber 101 and limits the angle of the passing laser light L1. The first slit 106 allows the laser light L1 reflected from the surface of the sample S to pass when the distance D is the analysis distance, and blocks the laser light L1 reflected from the same surface when the distance D is different from the analysis distance. Specifically, the first slit 106 is a slit that allows a straight line connecting the position P and the first detector 107 to pass through when the distance D is the analysis distance, and can be, for example, a slit with a width of 0.2 mm and a length of 10 mm.

[0029] The first detector 107 is disposed in the vacuum chamber 101 and detects the laser light L1 that has passed through the first slit 106. The first detector 107 may be a PSD (Position Sensitive Detector). The first detector 107 outputs a detection signal that indicates the intensity of the incident laser light L1 to the control unit 111.

[0030] The second laser light source 108 irradiates the surface of the sample S with laser light. As shown in FIG. 4 , the second laser light source 108 is disposed outside the vacuum chamber 101, and the laser light L2 emitted from the second laser light source 108 enters the interior of the vacuum chamber 101 through a window 122 and is incident on the surface of the sample S. Here, the second laser light source 108 is configured so that when the distance D is the analysis distance, the laser light L2 is incident on a position P, i.e., the same position as the laser light L1, and when the distance D is different from the analysis distance, the laser light L2 is incident on a position away from the position P. The second laser light source 108 is configured so that when the distance D is the analysis distance, the spot diameter of the laser light L2 on the surface of the sample S is 50 μm or less.

[0031] The second slit 109 is disposed in the vacuum chamber 101 and limits the angle of the passing laser light L2. The second slit 109 allows the laser light L2 reflected from the surface of the sample S to pass when the distance D is the analysis distance, and blocks the laser light L2 reflected from the same surface when the distance D is different from the analysis distance. Specifically, the second slit 109 is a slit that allows a straight line connecting the position P and the second detector 110 to pass through when the distance D is the analysis distance, and can be, for example, a slit with a width of 0.2 mm and a length of 10 mm.

[0032] The second detector 110 is disposed in the vacuum chamber 101 and detects the laser beam L2 that has passed through the second slit 109. The second detector 110 may be a PSD. The second detector 110 outputs a detection signal that indicates the intensity of the incident laser beam L2 to the control unit 111.

[0033] 5 is a schematic diagram of the first laser light source 105, the first slit 106, and the first detector 107 as viewed from a direction perpendicular to the Z direction (Y direction). As shown in the figure, if the angle of incidence of the laser light L1 with respect to the surface of the sample S, i.e., the angle between the optical axis of the laser light L1 and the same surface, is defined as angle α, then angle α is preferably 45°. Similarly, if the angle of incidence of the laser light L2 with respect to the surface of the sample S, i.e., the angle between the optical axis of the laser light L2 and the same surface, is defined as angle β (not shown), then angle β is preferably 45°. Note that angle α and angle β may be different angles.

[0034] 6 is a schematic diagram of the first laser light source 105, the first slit 106, the first detector 107, the second laser light source 108, the second slit 109, and the second detector 110 as viewed from the Z direction. As shown in the figure, if the angle formed by the optical axes of the laser light L1 and the laser light L2 as viewed from the Z direction is defined as angle γ, then angle γ is preferably 45° or more, and particularly preferably 90°.

[0035] The control unit 111 is connected to the first detector 107 and the second detector 110, and controls the drive mechanism of the stage 104 based on the outputs of these detectors. Specific control contents by the control unit 111 will be described later. The control unit 111 can be a general information processing device or control unit.

[0036] [Operation of the Analysis Apparatus] The analysis apparatus 100 operates as follows. FIG. 7 is a schematic diagram showing the operation of the analysis apparatus 100. It is assumed that the analysis distance, which is the distance D (see FIG. 3) most suitable for analysis, has been specified in advance. First, the sample S is placed on the stage 104, and the vacuum chamber 101 is evacuated. Next, as shown in FIG. 7, laser light L1 is emitted from the first laser light source 105, and laser light L2 is emitted from the second laser light source 108. At this time, the inside of the vacuum chamber 101 is not illuminated to block external light, stray light, etc.

[0037] Laser light L1 is reflected by the surface of sample S and enters first slit 106, but is blocked by first slit 106. Laser light L2 is also reflected by the surface of sample S and enters second slit 109, but is blocked by second slit 109. Therefore, first detector 107 and second detector 110 do not detect the laser light. While laser light L1 and laser light L2 are being irradiated, control unit 111 controls the drive mechanism of stage 104 to move stage 104 in the Z direction as shown by the arrow in the figure.

[0038] As the stage 104 moves, the distance D (see FIG. 3) decreases, and when the distance D matches the analysis distance, the laser light L1 passes through the first slit 106 and is incident on the first detector 107, as shown in FIG. 4, and is detected by the first detector 107. Similarly, the laser light L2 passes through the second slit 109 and is incident on the second detector 110, and is detected by the second detector 110.

[0039] The control unit 111 stops the driving mechanism of the stage 104 when the output of the first detector 107 exceeds the threshold value or when the output of the second detector 110 exceeds the threshold value. As a result, the sample S stops with the distance D coinciding with the analysis distance, i.e., the relative position of the sample S with respect to the analytical instrument 103 is aligned. In this state, as shown in FIG. 2 , the excitation radiation source 102 irradiates the sample S with X-rays and the analytical instrument 103 measures the emitted electrons, thereby enabling analysis of the sample S. The threshold value may be a preset value, or the driving mechanism of the stage 104 may be stopped when the detector output is detected to be 90% or more of a predetermined maximum detector output.

[0040] By using the first laser light source 105 and the second laser light source 108 (see FIG. 6 ), which have different optical axes as viewed in the Z direction, it is possible to align the sample S even if the surface of the sample S is tilted. The sample S may have warped or uneven surfaces due to processing steps involving heating. Therefore, the sample S is irradiated with laser light L1 and laser light L2 from different directions, and if the laser light is detected by either the first detector 107 or the second detector 110, the movement of the stage 104 is stopped, thereby enabling alignment of the sample S.

[0041] Furthermore, if it is certain that the sample S is not tilted, the analysis device 100 may not include the second laser light source 108, the second slit 109, and the second detector 110. In this case, the control unit 111 may stop the drive mechanism of the stage 104 when the output of the first detector 107 exceeds a threshold value. Furthermore, the analysis device 100 may include three or more laser light sources, three or more slits, and three or more detectors.

[0042] Furthermore, the first slit 106 limits the angle of the passing laser light L1 as described above. The first detector 107 typically has a cylindrical light entrance that limits the angle of the laser light incident on the light detection element. However, if the laser light is incident at a certain angle, the laser light may be reflected by the inner surface of the light entrance and reach the light detection element, resulting in erroneous detection. Therefore, by using the first slit 106, such reflection can be prevented, thereby preventing erroneous detection. The second slit 109 similarly prevents erroneous detection in the second detector 110.

[0043] Furthermore, in the above explanation, the sample S is aligned while the stage 104 is brought closer to the analytical instrument 103, but it is also possible to similarly align the sample S while moving the stage 104 away from the analytical instrument 103.

[0044] [Effects of the Analytical Apparatus] As described above, in the analytical apparatus 100, if the laser light reflected from the surface of the sample S is detected by either the first detector 107 or the second detector 110 while the stage 104 is moving, the movement of the stage 104 is stopped and the sample S is aligned. Because the detection of the laser light by the first detector 107 and the second detector 110 and the resulting stop of the movement of the stage 104 can be performed instantaneously, the sample S can be aligned in a short time, for example, about 10 seconds, after the movement of the stage 104 begins.

[0045] On the other hand, since conventional methods require approximately 150 to 180 seconds to position the sample, the method according to the present technology enables high-speed positioning of the sample S. Furthermore, the method according to the present technology does not involve uncertainties such as human judgment or image recognition, and only requires a comparison of the outputs of the first detector 107 and the second detector 110 with a threshold value, thereby enabling accurate positioning of the sample S.

[0046] [Application to Other Analytical Devices] The analytical device 100 has been described as an X-ray electron spectroscopy device, but it may also be another surface analysis device such as an Auger electron spectroscopy or secondary ion mass spectroscopy device. In the case of Auger electron spectroscopy, the excitation radiation source 102 irradiates the analysis target region R with an electron beam, and the analytical instrument 103 measures the kinetic energy of the Auger electrons emitted from the analysis target region R. In the case of secondary ion mass spectroscopy, the excitation radiation source 102 irradiates the analysis target region R with primary ions, and the analytical instrument 103 measures the mass of the secondary ions emitted from the analysis target region R.

[0047] The configuration is the same as that described above except for the excitation radiation source 102 and the analytical instrument 103. In the case of other surface analysis instruments, similar to the XPS analysis instrument, the alignment of the sample S with the analytical instrument 103 can be performed quickly and accurately.

[0048] [Regarding the embodiments of the present invention] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and various modifications can be made. Of the characteristic features described in the above-described embodiments, at least two of the characteristic features can be arbitrarily combined.

[0049] REFERENCE SIGNS LIST 100: Analysis device 101: Vacuum chamber 102: Excitation radiation source 103: Analysis equipment 104: Stage 105: First laser light source 106: First slit 107: First detector 108: Second laser light source 109: Second slit 110: Second detector 111: Control unit

Claims

1. An analytical device comprising: an analytical instrument for analyzing a sample; a first laser light source that emits laser light; a first slit that allows laser light emitted from the first laser light source and reflected by the surface of the sample to pass when the distance between the sample and the analytical instrument is a predetermined distance, and blocks laser light emitted from the first laser light source and reflected by the surface of the sample when the distance between the sample and the analytical instrument is different from the predetermined distance; a first detector that detects the laser light that has passed through the first slit; and a stage on which the sample is placed, which is movable in a first direction that moves toward or away from the analytical instrument.

2. An analytical device according to claim 1, further comprising: a second laser light source that emits laser light; a second slit that allows the laser light emitted from the second laser light source and reflected by the surface of the sample to pass when the sample and the analytical instrument are at the specified distance, and that blocks the laser light emitted from the second laser light source and reflected by the surface of the sample when the distance between the sample and the analytical instrument is different from the specified distance; and a second detector that detects the laser light that has passed through the second slit.

3. An analytical device according to claim 2, wherein when the sample and the analytical instrument are at the predetermined distance, the laser light emitted from the first laser light source and the laser light emitted from the second laser light source are incident on the same position on the surface of the sample.

4. An analytical device according to claim 3, wherein the optical axis of the first laser light source and the optical axis of the second laser light source are perpendicular to each other when viewed from the first direction.

5. An analytical device according to claim 1, further comprising: a drive mechanism that moves the stage in the first direction to change the distance between the sample and the analytical instrument; and a control unit that controls the drive mechanism based on the output of the first detector.

6. An analytical device according to claim 5, wherein the control unit stops the movement of the stage when the output of the first detector exceeds a threshold value.

7. An analytical device according to claim 2, further comprising: a drive mechanism that moves the stage in the first direction to change the distance between the sample and the analytical instrument; and a control unit that controls the drive mechanism based on the outputs of the first detector and the second detector.

8. An analytical device according to claim 7, wherein the control unit stops the movement of the stage when the output of either the first detector or the second detector exceeds a threshold value.

9. An analytical device according to claim 2, wherein the first slit, the first detector, the second slit, the second detector and the stage are arranged inside a vacuum chamber, and the first laser light source and the second laser light source are arranged outside the vacuum chamber.

10. The analytical device according to claim 2, wherein the first detector and the second detector are PSDs (Position Sensitive Detectors).

11. The analytical device according to claim 1, wherein the analytical instrument is an instrument that performs X-ray photoelectron spectroscopy.

12. An analytical method comprising the steps of: placing a sample on a mounting surface of a stage; moving the stage in a first direction that is a direction toward or away from the analytical instrument; irradiating a laser beam from a first laser light source onto the surface of the sample; when the sample and the analytical instrument are at a predetermined distance, allowing the laser beam that has been emitted from the first laser light source and reflected by the surface of the sample to pass; and controlling the position of the stage using the output of a first detector that detects the laser beam that has been emitted from the first laser light source and passed through a first slit that blocks the laser beam that has been reflected by the surface of the sample when the distance between the sample and the analytical instrument is different from the predetermined distance.

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