JP2006133000A - Micro stack inspection system - Google Patents

Abstract

【Task】
Provided is a micro-laminate structure inspection device capable of measuring the film thickness and interface width of a nano thin film laminate in an area of a measurement range of 1 mm or less.
[Solution]
There is a spectroscopic element and a condensing element between the X-ray source and the sample. X-rays generated by the X-ray source are monochromatized by the spectroscopic element, and the X-ray fluxes in the horizontal and vertical directions are collected at the sample position by the condensing element. Measure the energy and intensity of incident X-rays scattered by a thin-film scatterer between the spectroscopic element and the sample, which is focused to a size of 10 μm or less and 1 mm or less, and irradiated to the sample with a scattered X-ray detector. Measure the X-rays specularly reflected by the sample with the reflection X-ray detector, and put the output of the scattered X-ray detector and the reflection X-ray detector to match the energy of the incident X-ray and the reflected X-ray to measure And an energy-synchronized measurement device that counts the intensity of scattered X-rays and reflected X-rays, and measures the reflectance without the influence of fluorescent X-rays from the sample while changing the energy of the incident X-rays. Structural inspection equipment.
[Selection] Figure 1

Description

  The present invention relates to a measurement method and an inspection apparatus for the film thickness and interface width of a micro area of a thin film laminate.

  In the field of semiconductor devices and magnetic devices, in order to increase the functionality and performance of elements, the formed films have become extremely thin and the number of stacked layers has increased. In addition, in current electronic devices such as semiconductors and magnetic devices, control of the laminated film interface is also performed in order to control electron scattering at the laminated film interface.

  Conventionally, ellipsometry and fluorescent X-ray methods are used as methods for evaluating the film thickness of a laminated film. The ellipsometry method is a method in which polarized light is incident on a thin film sample having a flat surface, the change in the polarization state of reflected light is measured, and the thickness and refractive index of the sample thin film are known. However, since this method uses light, there is a problem in that measurement is only possible for a sample that is transparent to light. The fluorescent X-ray method is a method of measuring a fluorescent X-ray generated in a sample and estimating a film thickness from the intensity. In the case of this method, the total amount of elements that generate fluorescent X-rays is known, and it is not a method for directly measuring the film thickness, and when a plurality of thin films containing the same element are laminated, the film thickness is analyzed separately. The inability to do so is a problem. In addition, neither the ellipsometry method nor the fluorescent X-ray method can obtain information on the interface of the laminated film.

The cross-sectional TEM observation of the device can measure the film thickness of the laminated film with very high spatial resolution. The interface width can also be estimated. However, for TEM observation, the sample is 100
It is necessary to make a slice of less than nm, which is a fracture analysis. For this reason, although it can be used for failure analysis, it is difficult to use it as an inspection apparatus.

  As a method for measuring the film thickness and interface width of a laminated thin film in a nondestructive manner, there is an X-ray reflectivity method.

  There are two types of X-ray reflectivity methods, one is a method in which monochromatic X-rays are incident on the sample surface and the reflectance is measured while changing the incident angle, and the other is white X-rays on the sample. This is a method for measuring the wavelength dependence of the reflectance upon incidence. Both methods analyze the film thickness from the interference of X-rays reflected from the sample surface and interface. In addition, since the interface width affects the reflection at the surface and the interface, the width of each interface of the laminated film can be obtained by analyzing the X-ray reflectance profile in detail.

JP-A-6-213833

  However, since the conventional X-ray reflectometer was 20 μm even if the beam width was small, even if it was incident on the sample at 0.5 °, it spreads 120 times on the sample surface and became 2.4 mm. There is a problem that the measurement area is wide. When the measurement region is wide, in addition to the interface width due to the interface unevenness of the laminated film, the problem that the waviness of the substrate is also superimposed and analyzed as the interface unevenness also occurs. It is very important to analyze the interface width while minimizing the influence of substrate undulations, because it is the unevenness of the film interface that affects the device characteristics.

  Even if the X-rays are reduced to about 10 μm with a Fresnel zone plate or the like, the usable X-rays are monochromatic, and it is necessary to change the incident angle to the sample from 0.1 ° to 2-3 °. At this time, the sample and the rotation center of the incident angle are made equal to 10% or less of the beam size, and the position reproduction accuracy of the rotation center of the goniometer that rotates the sample to change the incident angle is also made 10% or less of the beam size. There is a need, but this is very difficult.

  As another method, it is conceivable to reduce the X-rays to about 10 μm with a condenser mirror. When monochromatic X-rays are collected by a condensing mirror, the same problem as in the Fresnel zone plate occurs, and it is difficult to measure the X-ray reflectivity from an area of 1 mm square or less on the sample surface.

  In the case of the method of narrowing the beam width with a condensing mirror, white X-rays can be incident on the sample and the energy dispersive reflectance can be measured. Since this method does not require the sample to be rotated, the above-described problem of the sample position and the position accuracy of the goniometer rotation center are eliminated. However, since the element constituting the sample is excited by incident X-rays and emits fluorescent X-rays, the reflectance cannot be measured in the energy range near the absorption edge of the element. In particular, transition metals used in magnetic devices have Kα rays and Kβ rays in the energy range of 6 keV to 9 keV. Therefore, it is necessary to measure the reflectance while avoiding this energy range. It is difficult to measure.

  Further, when measuring reflectance by wavelength scanning, the influence of the fluorescent X-rays described above cannot be avoided unless a spectral crystal is inserted in front of the detector. When the reflectance is measured with the spectral crystal inserted, it is necessary to change the diffraction angle of the spectral crystal in the same way when the energy of the incident X-ray is changed. In this case, since the inaccuracy of the diffraction angle of the spectral crystal leads to an increase or decrease in the reflection intensity, it is necessary to constantly obtain the angle at which the maximum value of the diffraction intensity is obtained by locking the spectral crystal. However, this method requires a very long time to measure one point, so it is difficult to measure a wide range of reflectance.

  Further, as a method not using a spectroscopic crystal, a method of removing fluorescent X-rays using a detector with high energy resolution is conceivable. In the case of this method, when the reflectance with high energy X-rays is measured, the intensity of fluorescent X-rays becomes stronger than the intensity of reflected X-rays, making it difficult to measure the intensity of reflected X-rays. In addition, in order to change the incident energy, it is necessary to measure the energy spectrum of reflected X-rays at each measurement point and separate the reflected X-rays and fluorescent X-rays off-line, and it takes a long time to measure and derive the reflectance profile. It becomes.

  Accordingly, an object of the present invention is to provide a micro-part stack structure inspection apparatus capable of measuring the X-ray reflectivity from a region of 1 mm square or less on the sample surface without the influence of fluorescent X-rays.

  The feature of the present invention that achieves the above object is that the X-ray generated by the X-ray source is monochromatic by the spectroscopic element, and the incident X-ray scattered by the scatterer arranged downstream of the spectroscopic element is measured by the X-ray detector. The output is input to the energy synchronous measurement device, the energy of scattered X-rays is analyzed by a multi-channel counting circuit, the peak voltage is obtained, and the width of the measurement window is added to or subtracted from the obtained peak voltage. Determine the voltage range, measure the scattering intensity, and input the voltages above and below the measurement window into the channel analyzer for measuring the intensity of the reflected X-ray, and use it as a measurement window voltage to measure the reflected X-ray intensity. In the structural inspection equipment.

  Assuming that the direction of the scattering vector of the spectroscopic element is the Y direction, the direction perpendicular to it is the Z direction, and the X-ray traveling direction is the X direction, the Y direction condensing element downstream of the spectroscopic element collects the Y direction to 1 mm or less. The Z direction is condensed to 10 μm or less by a light condensing element in the Z direction. The sample is placed on a sample stage that can move in the X, Y, and Z directions, and the sample stage is on a goniometer that can rotate the sample and the detector coaxially. The sample stage and the goniometer are arranged so that the scattering vector of the sample is in the Z direction. At this time, the angle formed by the scattering vector of the sample and the Z direction is within ± 45 °. If the angle between the sample and the incident X-ray (incident angle) is 0.6 °, the incident X-ray spreads on the sample surface to 1 mm × 1 mm. The incident angle depends on the maximum energy used for the measurement and the width of the focused X-ray, so a suitable incident from the range of 0.1 ° to 3 ° is required to measure the reflectivity from a 1mm x 1mm area. It is necessary to select a corner. The intensity of the specularly reflected X-ray is measured with an X-ray detector. The output is input to an energy synchronous measurement device, and the intensity is measured in a measurement window synchronized with the energy of incident X-rays. The intensity of the incident X-ray is calculated from the obtained scattered X-ray intensity, and the intensity of the reflected X-ray is divided by the intensity of the incident X-ray to obtain the X-ray reflectivity. While changing the energy of incident X-rays with a spectroscopic element, the X-ray reflectivity is measured, and the energy dependency of the X-ray reflectivity is obtained.

  Another method is to use a spectroscopic crystal. In this case, the spectroscopically reflected X-ray is placed on the arm on which the detector is placed, and a spectral crystal curved so as to have a diffraction width of about 100 eV (for example, 90 to 110 eV) is arranged. And the reflected X-ray intensity is measured with a reflected X-ray detector. For the energy of incident X-rays, the X-ray detector measures incident X-rays scattered by a scatterer arranged downstream of the spectroscopic element. The output of the detector is input to the wavelength synchronization device, and the energy of scattered X-rays is analyzed by a multi-channel counting circuit to obtain the peak voltage. Add or subtract the width of the measurement window to the obtained peak voltage, determine the voltage range of the measurement window, measure the scattering intensity, calculate the diffraction angle of the spectral crystal from the energy of scattered X-rays, and obtain the obtained angle By moving the spectral crystal and the reflected X-ray detector, only the reflected X-ray having the same energy as the incident X-ray is measured. The intensity of the obtained reflected X-ray is divided by the intensity of the incident X-ray calculated from the scattered X-ray intensity to obtain the X-ray reflectivity. While changing the energy of incident X-rays with a spectroscopic element, the X-ray reflectivity is measured, and the energy dependency of the X-ray reflectivity is obtained.

  According to the present invention, it is possible to provide a micro stacked structure inspection apparatus capable of accurately measuring an X-ray reflectance from a region of 1 mm × 1 mm or less and measuring a film thickness and an interface width.

  Examples will be described below.

  Examples of the present invention will be described. FIG. 1 shows an embodiment. The X-ray 2 generated by the X-ray source 1 is monochromatized by the first symmetric reflective crystal 3 and the second symmetric reflective crystal 4. The monochromatic X-ray is formed into a z-direction of 100 μm and a y-direction of 10 mm by a slit (not shown), and then enters the vertical condenser mirror 8 through the scatterer 5. Incident X-rays are scattered by the scatterer 5, and the scattered X-ray detector 7 measures the intensity and energy of the scattered X-rays 6. The X-rays are collected on the sample 10 by the vertical condenser mirror 8 and the horizontal condenser mirror 9. The intensity of the reflected X-ray 11 that is specularly reflected by the sample 10 is measured by the reflected X-ray detector 12. The measurement signal of the scattered X-ray detector 7 and the measurement signal of the reflected X-ray detector 12 are input to the energy synchronous measuring device 13, and the reflected X-ray intensity and the incident X-ray intensity having the same energy as the incident X-ray are obtained and reflected. Calculate the rate. The reflectance measurement control unit 16 uses the incident energy control unit 14 to change the energy of incident X-rays in the first symmetric reflective crystal 3, and emits in a fixed position where the X-ray position and direction are constant in the second symmetric reflective crystal 4. It adjusts to conditions, the reflectance in each energy is obtained from the energy synchronous measuring device 13, and the energy dependence of X-ray reflectance is displayed on the display part 17. FIG. Further, the reflectance measurement control unit 16 uses the reflectometer control unit 15 before the measurement so that the parallelism between the sample and the incident X-ray and the specular reflection X-ray is incident on the reflection X-ray detector. Adjust the position of the sample-reflected X-ray detector.

  Next, the function of each component will be described. Synchrotron radiation was used for the X-ray source 1. Si (111) single crystal was used as the reflective crystal. The energy used for the measurement is 5 keV to 22 keV, and the angle of the first reflective crystal 3, the angle of the second reflective crystal 4, and the distance between the two crystals are adjusted so as to emit in a fixed position, and the respective angles and positions are adjusted. Record in the incident energy controller. As a result, when the incident X-ray energy is given from the reflectance measurement control unit 16, the incident energy control unit drives the first reflective crystal 3 and the second reflective crystal 4 so as to emit at a fixed position with the specified energy. Is possible.

  The monochromatic X-ray was measured by the scattered X-ray detector 7 by measuring the energy and intensity of the scattered X-ray scattered by the scatterer 5 made of a Kapton film arranged at an angle of 45 degrees with the X-ray. . Since the scattered X-ray detector 7 uses the same detector as the reflected X-ray detector 12, it is necessary to be able to separate the Kα ray and Kβ ray of the element having the adjacent atomic number, and therefore the energy resolution is set to 300 eV. In addition, since a dynamic range of about 5 digits is required, a Si Drift detector was used. In the vertical direction of the X-rays transmitted through the scatterer 5, the X-ray source 1 is used as a light source, and the light is condensed to about 10 μm on the sample 10 by the vertical condenser mirror. In the horizontal direction, the second reflective crystal 4 is used as a light source, and the light is condensed to about 1 mm on the sample 10 by a horizontal condenser mirror. In the X-ray reflectivity measurement, since the grazing incidence occurs, the width of the X-ray in the z-axis direction increases about 100 times. Therefore, a measurement area of 1 mm × 1 mm can be realized on the sample 10. As the condenser mirror, a parabolic mirror in which platinum was deposited to 100 nm on fused quartz was used. The reflected X-ray 11 that is specularly reflected by the sample 10 is measured for energy and intensity by a reflected X-ray detector 12. Signals from the scattered X-ray detector 7 and the reflected X-ray detector 12 are input to the energy synchronous measuring device 13 and output as reflectance.

The energy synchronous measuring device 13 is demonstrated according to FIG. The preamplifier output signal of the scattered X-ray detector 7 is amplified by an amplifier 18 and input to a multichannel analysis circuit 19. By correcting the relationship between the channel and energy in advance, the output of the multi-channel analysis circuit 19 becomes the energy spectrum of the scattered X-ray 6 measured by the scattered X-ray detector 7. The spectrum signal is displayed on the display unit 20 and input to the peak detection circuit 21. There are various methods for detecting the peak position of the spectrum. In this embodiment, a detection method using differentiation is used. The spectrum signal is subjected to 5-channel smoothing processing by the smoothing circuit 22, and the obtained spectrum is converted to a differentiation signal by the differentiation circuit 23. The maximum value / minimum value detection circuit 24 obtains the energy of the maximum and minimum values of the differential signal, and the energy at which the differential signal becomes 0 between the maximum value and the minimum value by the zero level detection circuit is the energy of the incident X-ray. Corresponding to The peak detection circuit 21 finally outputs a voltage corresponding to the incident energy as V _E. The energy width to be measured is input as voltage ΔW from the detection window width input unit 26 to the detection window voltage generation circuit 27. The energy width at this time can be determined by the performance of the detector, and can be, for example, twice the half-value width. The output voltage VE of the peak detection circuit 21 is also input to this circuit. The detection window voltage generation circuit 27 has a low voltage level V _L = V _E −.
ΔW and a high voltage level V _H = V _E + ΔW are output. The two output voltages and the output signal of the amplifier 18 are input to the single channel analysis circuit 28, and after wave height analysis, are input to the first channel of the 2-channel counting circuit 29 and counted as scattered X-ray intensity. Since the intensity of the scattered X-ray 6 and the intensity of the incident X-ray have a proportional relationship, the intensity of the obtained scattered X-ray is converted into the incident X-ray intensity by the reflectance calculator. Next, the preamplifier output signal of the reflection X-ray detector 12 is amplified by the amplifier 18. The amplification factor of the amplifier is adjusted so that X-rays having the same energy are output at the same voltage. By inputting the two output voltages of the amplifier output and the detection window voltage generation circuit 27 to the single channel analysis circuit 28, the wave height analysis at the same energy window position and width can be automatically performed. This output is input to the second channel of the two-channel counting circuit 29 and counted as the intensity of the reflected X-ray. X-ray reflectivity is obtained by inputting the intensity of the obtained reflected X-rays to the reflectance calculation device 30 and dividing by the incident X-ray intensity obtained at the same time. The reflectance measurement control unit 16 gives measurement energy to the incident energy control unit 14 and repeats the measurement of receiving the reflectance output from the energy synchronous measurement device 13 from 5 keV to 25 keV, thereby measuring the energy dependency of the X-ray reflectance. The result is shown on the display unit 17.

Next, work to make the surface of the sample 10 parallel to the X-ray (hereinafter referred to as pivoting work) is: 1) Move the sample so as to block the X-ray so that the intensity of the incident X-ray is 50% of the original. (Z-axis) 2) The sample is rotated on an axis perpendicular to the scattering plane composed of the incident X-ray and the normal of the sample surface, and adjusted to an angle at which the incident X-ray intensity becomes maximum. The steps 1) and 2) are repeated, and the sample is adjusted so that the maximum strength is 50% of the initial value, and the strength decreases when the sample is rotated. In addition, the sample is rotated 180 ° and steps 1) and 2) are repeated. The difference between the rotation axis of the sample stage and the X-ray position can be measured from the difference in the Z-axis value at this time, and the rotation center of the sample stage and the X-ray position can be matched with an accuracy of 1 μm. This method is called a halving method, but the accuracy of parallelism between the X-ray and the sample surface is as low as about 0.1 °. After the halving, the incident angle / scattering angle is moved to the total reflection angle, and the incident angle is set to 0.01 by adjusting the Z-axis movement and the incident angle of the sample so that the reflected X-ray intensity becomes maximum. ° It can be erected with a degree of accuracy. In this embodiment, when this method is used, the alignment accuracy between the sample surface and the center of the rotating shaft is about 1 μm. Awaji et al. (Japanese Patent Application No. 7-260712) proposes a method of measuring the total reflection angle while rotating the sample and setting the angle so that the angle does not change due to the rotation of the sample. Awaji et al. Use this method to set the shaft with an accuracy of 0.005 °. Even when the method of Awaji et al. Is applied to the present embodiment, the accuracy of the rotation center of the sample stage and the X-ray position, and the accuracy of the position of the sample surface and the center of the rotation axis are about 1 μm. When measuring the reflectance while changing the incident angle, this accuracy causes a problem in that the X-ray irradiation region is displaced from the sample position. However, since the incident angle is fixed in this embodiment, this accuracy is not a problem. The angle between the sample and the X-ray is set to 0.5 °, and the sample is scanned along the XY axis while measuring the fluorescent X-ray from the sample with a fluorescent X-ray detector (not shown). By mapping with the fluorescent X-ray unique to the sample position, the X-ray can be accurately applied to the sample position. Further, the angle between the sample and the X-ray is set to 1.0 °, and the sample is scanned along the XY axis while measuring the fluorescent X-ray from the sample with a fluorescent X-ray detector (not shown). By mapping with the fluorescent X-ray unique to the sample position, the X-ray can be accurately applied to the sample position even at an incident angle of 1.0 °.

  Next, the characteristic of the condensed X-ray of this embodiment will be described. The full width at half maximum of the focused beam obtained from the scanning of the knife edge provided on the sample stage is 10 μm vertically and 100 μm horizontally, and the X-ray intensity is 2E7 cps at a storage ring current value of 300 mA and an X-ray energy of 80 keV. It was. By disposing a slit that restricts the vertical direction between the condenser mirror 9 and the sample 10, the spread of the bottom of the condensed beam was reduced and the width of the beam could be 8 μm. The X-ray intensity at this time was 1E7 cps.

Next, the result of measuring a magnetic head element as the sample 10 will be described using this example. The sample was 50 μm wide and 500 μm long. The sample was axially aligned by the adjustment method described above, and the position of the sample was aligned by mapping with fluorescent X-rays (CoKα) from Co. The measurement positions were adjusted to be near the center of the sample at incident angles of 0.5 ° and 1.0 °, respectively. FIG. 3 shows the reflectance profile measured in this example. The horizontal axis is the scattering vector (= 4πsmθ / λ, θ: incident angle, λ: wavelength), and the energy of the reflectance profile 31 measured at an incident angle of 0.5 ° is measured at the lower axis and the incident angle of 1.0 °. The energy of the reflectance profile 32 is shown on the upper axis. In the conventional method, the fluorescence X-ray peaks of Cu, Co, and Ni contained in the sample overlap, and the reflection profile at the position of the fluorescence X-ray energy 33 of the sample element cannot be measured. However, in this example, no peak was observed at the position of the fluorescent X-ray energy 33 of the sample element, and the change in the reflection profile due to the absorption change at the position of the absorption edge energy 34 of the sample element could be measured. In addition, there is a portion where the reflectance profile 31 measured at an incident angle of 0.5 ° and the reflectance profile 32 measured at an incident angle of 1.0 ° overlap, but here also the reflectance measurement can be accurately performed. It could be confirmed.

  Another embodiment of the present invention will be described. FIG. 4 shows an outline of the present embodiment. The X-ray 2 generated by the X-ray source 1 is monochromatized by the first symmetric reflective crystal 3 and the second symmetric reflective crystal 4. The monochromatic X-ray is formed into a z-direction of 100 μm and a y-direction of 10 mm by a slit (not shown), and then enters the vertical condenser mirror 8 through the scatterer 5. Incident X-rays are scattered by the scatterer 5, and the scattered X-ray detector 7 measures the intensity and energy of the scattered X-rays 6. The X-rays are collected on the sample 10 by the vertical condenser mirror 8 and the horizontal condenser mirror 9. The intensity of the reflected X-rays 11 specularly reflected by the sample 10 is measured by the X-ray detector 36 after being subjected to energy spectroscopy with the curved spectral crystal 35. The measurement signal of the scattered X-ray detector 7 and the measurement signal of the reflected X-ray detector 12 are input to the wavelength synchronization device 37, and the curved spectral crystal 35 and X are measured so that the reflected X-ray having the same energy as the incident X-ray is measured. The angle and position of the line detector 36 are adjusted. The wavelength synchronization device 37 obtains the reflected X-ray intensity and the incident X-ray intensity having the same energy as the incident X-ray, and calculates the reflectance. The reflectance measurement control unit 16 uses the incident energy control unit 14 to change the energy of incident X-rays in the first symmetric reflective crystal 3, and emits in a fixed position where the X-ray position and direction are constant in the second symmetric reflective crystal 4. The reflectance at each energy is obtained from the wavelength synchronization device 37 by adjusting the conditions, and the energy dependency of the X-ray reflectance is displayed on the display unit 17. Further, the reflectance measurement control unit 16 uses the reflectometer control unit 15 before the measurement so that the parallelism between the sample and the incident X-ray and the specular reflection X-ray is incident on the reflection X-ray detector. Adjust the position of the sample-reflected X-ray detector.

Next, the function of each component will be described. The X-ray source 1 was synchrotron radiation from the high energy accelerator research facility synchrotron radiation experiment facility. Si (111) single crystal was used as the reflective crystal. The energy used for the measurement is 5 keV to 22 keV, and the angle of the first reflective crystal 3, the angle of the second reflective crystal 4, and the distance between the two crystals are adjusted so as to emit in a fixed position, and the respective angles and positions are adjusted. Record in the incident energy controller. Thus, when the incident X-ray energy is given from the reflectance measurement control unit 16, the incident energy control unit drives the first reflective crystal 3 and the second reflective crystal 4 so as to emit at a fixed position with the specified energy. Is possible. The monochromatic X-ray was measured by the scattered X-ray detector 7 by measuring the energy and intensity of the scattered X-ray scattered by the scatterer 5 made of a Kapton film arranged at an angle of 45 degrees with the X-ray. . Since the scattered X-ray detector 7 measures the energy of incident X-rays, an energy resolution of about 300 eV and a dynamic range of about five digits are required, and therefore a Si Drift detector was used. In the vertical direction of the X-rays transmitted through the scatterer 5, the X-ray source 1 is used as a light source, and the light is condensed to about 10 μm on the sample 10 by the vertical condenser mirror. In the horizontal direction, the second reflective crystal 4 is used as a light source, and the light is condensed to about 1 mm on the sample 10 by a horizontal condenser mirror. In the X-ray reflectivity measurement, since the grazing incidence occurs, the width of the X-ray in the z-axis direction increases about 100 times. Therefore, a measurement area of 1 mm × 1 mm can be realized on the sample 10. As the condenser mirror, a parabolic mirror in which platinum was deposited to 100 nm on fused quartz was used. The reflected X-ray 11 specularly reflected by the sample 10 is subjected to energy spectroscopy by the curved spectral crystal 35 and the intensity is measured by the X-ray detector 36. The curved spectral crystal 35 is curved by fixing one of Ge (1H) crystals having a thickness of 0.3 mm and pushing the other. The degree of curvature was adjusted so that CuKα and NiKβ could be separated. The X-ray detector 36 is disposed on a detector base (not shown) coaxial with the rotational axis of the curved spectral crystal 35. Since the X-ray detector 36 is used in combination with the curved spectral crystal 35, the detector itself does not require high energy resolution. Therefore, a NaI scintillation detector having a dynamic range of 5 digits or more was used. Signals from the scattered X-ray detector 7 and the X-ray detector 36 are input to the wavelength synchronization device 37 and output as reflectance.

The wavelength synchronization device 37 will be described with reference to FIG. The preamplifier output signal of the scattered X-ray detector 7 is amplified by an amplifier 18 and input to a multichannel analysis circuit 19. By correcting the relationship between the channel and energy in advance, the output of the multi-channel analysis circuit 19 becomes the energy spectrum of the scattered X-ray 6 measured by the scattered X-ray detector 7. The spectrum signal is displayed on the display unit 20 and input to the peak detection circuit 21. There are various methods for detecting the peak position of the spectrum. In this embodiment, a detection method using differentiation is used. The spectrum signal is subjected to 5-channel smoothing processing by the smoothing circuit 22, and the obtained spectrum is converted to a differentiation signal by the differentiation circuit 23. The maximum value / minimum value detection circuit 24 obtains the energy of the maximum and minimum values of the differential signal, and the energy at which the differential signal becomes 0 between the maximum value and the minimum value by the zero level detection circuit is the energy of the incident X-ray. Corresponding to The peak detection circuit 21 finally outputs a voltage corresponding to the incident energy as V _E. The energy width to be measured is input to the detection window voltage generation circuit 27 from the detection window width input unit as the voltage ΔW. The output voltage V _E of the peak detection circuit 21 is also input to this circuit. The detection window voltage generation circuit 27 outputs a low voltage level V _L = V _E −ΔW and a high voltage level V _H = V _E + ΔW. The two output voltages and the output signal of the amplifier 18 are input to the single channel analysis circuit 28, and after wave height analysis, are input to the first channel of the 2-channel counting circuit 29 and counted as scattered X-ray intensity. Since the intensity of the scattered X-ray 6 and the intensity of the incident X-ray have a proportional relationship, the intensity of the obtained scattered X-ray is converted into the incident X-ray intensity by the reflectance calculator. Next, a voltage (V _E ) corresponding to the incident energy output from the peak detection circuit 21 is input to the X-ray energy / wavelength converter, and the wavelength of the incident X-ray is obtained. The surface distance (d value) of Ge (111) and the wavelength (λ) of incident X-rays input from the curved spectral crystal surface distance input unit are input to the diffraction angle calculation unit 40, and the same wavelength as the incident X-rays is the curved spectral crystal. The black angle (θ _B ) split at 35 is obtained. The biaxial motor controller 41 and the motor driver 42 are controlled so that the positions of the curved spectral crystal 35 and the X-ray detector 36 satisfy the black condition, and X-rays having the same wavelength as the incident X-ray are curved spectral crystals 35. The angle between the curved spectral crystal 35 and the counter arm is adjusted so that the spectrum is measured by the X-ray detector 36. Next, the preamplifier output signal of the X-ray detector 36 is amplified by the amplifier 18. By inputting the amplifier output to the single channel analysis circuit 28, the wave height analysis of the reflected X-ray having the same wavelength as the incident X-ray can be automatically performed. The window width of the single channel analysis circuit 28 is input from the reflection X-ray window width input unit 34. This output is input to the second channel of the two-channel counting circuit 29 and counted as the intensity of the reflected X-ray. X-ray reflectivity is obtained by inputting the intensity of the obtained reflected X-rays to the reflectance calculation device 30 and dividing by the incident X-ray intensity obtained at the same time. The reflectance measurement control unit 16 gives the measurement energy to the incident energy control unit 14 and repeats the measurement of receiving the reflectance output from the wavelength synchronization device 37 from 5 keV to 25 keV, thereby measuring the energy dependence of the X-ray reflectance. The result is shown on the display unit 17.

  The shafting work for making the sample surface and X-ray parallel to each other and the characteristics of the focused X-ray in this embodiment are the same as those in the first embodiment.

Next, the result of measuring a magnetic head element as the sample 10 will be described using this example. The sample was 50 μm wide and 500 μm long. The sample was axially aligned by the adjustment method described above, and the position of the sample was aligned by mapping with fluorescent X-rays (CoKα) from Co. The measurement positions were adjusted to be near the center of the sample at incident angles of 0.5 ° and 1.0 °, respectively. Depending on the adjustment of the curved spectral crystal 35, the reflectance profile measured in this example is also the same as in FIG. Although FIG. 3 has already been described, the horizontal axis represents the scattering vector (= 4πsin θ / λ, θ: incident angle, λ: wavelength), and the energy of the reflectance profile 31 measured at an incident angle of 0.5 ° is the lower axis. The energy of the reflectance profile 32 measured at an angle of 1.0 ° is shown on the upper axis. In the conventional method, the fluorescence X-ray peaks of Cu, Co, and Ni contained in the sample overlap, and the reflection profile at the position of the fluorescence X-ray energy 33 of the sample element cannot be measured. However, in this example, no peak was observed at the position of the fluorescent X-ray energy 33 of the sample element, and the change in the reflection profile due to the absorption change at the position of the absorption edge energy 34 of the sample element could be measured. In addition, there is a portion where the reflectance profile 31 measured at an incident angle of 0.5 ° and the reflectance profile 32 measured at an incident angle of 1.0 ° overlap, but here also the reflectance measurement can be accurately performed. It could be confirmed.

Examples of the present invention. The operation | movement flow of the energy synchronous measuring device of this invention. The energy dispersion type reflectance profile measured by the present invention. 4 shows another embodiment of the present invention. The operation | movement flow of the wavelength synchronizing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... X-ray source, 2 ... X-ray, 3 ... 1st symmetrical reflective crystal, 4 ... 2nd symmetrical reflective crystal, 5 ... Scatterer, 6 ... Scattered X-ray, 7 ... Scattered X-ray detector, 8 ... Vertical collection Light mirror, 9 ... Horizontal focusing mirror, 10 ... Sample,
DESCRIPTION OF SYMBOLS 11 ... Reflected X-ray, 12 ... Reflected X-ray detector, 13 ... Energy synchronous measuring device, 14 ... Incident energy control part, 15 ... Reflectance meter control part, 16 ... Reflectance measurement control part, 17, 20 ... Display part , 18 ... amplifier, 19 ... multi-channel analysis circuit, 21 ... peak detection circuit, 22 ... smoothing circuit, 23 ... differentiation circuit, 24 ... maximum / minimum value detection circuit, 25 ... 0 level detection circuit,
26: Detection window width input unit, 27: Detection window voltage generation circuit, 28 ... Single channel analysis circuit, 29 ... 2 channel counting circuit, 30 ... Reflectance calculator, 31 ... Reflectance profile measured at an incident angle of 0.5 °, 32 ... Reflectance profile measured at an incident angle of 1.0 °, 33 ... Fluorescent X-ray energy of the sample element, 34 ... Absorption edge energy of the sample element, 35 ... Curved crystal, 36 ... X-ray detector, 37 ... Wavelength Synchronizer, 38 ... curved spectral crystal plane interval input unit, 39 ... X-ray energy / wavelength conversion unit, 40 ... diffraction angle calculation unit, 41 ... motor controller, 42 ... motor driver, 43 ... reflection X-ray window width input unit.

Claims (7)

An X-ray source, a spectroscopic element for monochromating X-rays generated by the X-ray source, a light-collecting element that makes the size of the X-ray bundle irradiated to the sample 10 μm or less in the horizontal direction and 1 mm or less in the vertical direction, A multilayer thin film inspection apparatus having a reflection X-ray detector for detecting X-rays reflected by a sample,
A thin film scatterer that is provided between the spectroscopic element and the sample position and scatters incident X-rays, and an energy resolution 300 that measures energy and intensity of the X-rays scattered by the thin film scatterer.
The scattering X-ray detector of eV or less and the energy information of the scattered X-ray obtained from the scattered X-ray detector are used to limit the energy range of the reflected X-ray measured by the reflected X-ray detector, and the scattering An energy-synchronized measurement device that measures the intensities of X-rays and reflected X-rays, and a calculation device that obtains the X-ray reflectivity from the intensity of incident X-rays obtained from the scattered X-ray intensity and the intensity of the reflected X-ray And
A control device that acquires the X-ray reflectivity of each energy while changing the energy of incident X-rays with a spectroscopic element using the energy synchronous measurement device and the calculation device, and the energy of the X-ray reflectivity acquired by the control device A laminated thin film inspection apparatus, comprising: an output device that displays dependency. The multilayer thin film inspection apparatus according to claim 1,
A laminated thin film inspection apparatus comprising a spectral crystal provided between a sample position and the reflection X-ray detector. The multilayer thin film inspection apparatus according to claim 1,
The laminated thin film inspection apparatus, wherein the reflection X-ray detector has an energy resolution of 300 eV or less. The multilayer thin film inspection apparatus according to claim 3,
The energy-synchronized measuring apparatus inputs a peak width of the scattered X-ray, obtains a peak voltage of the scattered X-ray, measures a scattered X-ray intensity using the peak voltage and the peak width as a measurement range, and the peak width And the peak voltage is used as the measurement range of the reflected X-ray intensity. The laminated thin film inspection apparatus according to claim 2,
The wavelength synchronization device inputs the peak width of the scattered X-ray, obtains the peak voltage from the measured value of the scattered X-ray detector, measures the scattered X-ray intensity using the peak voltage and the peak width as a measurement range, The energy of the scattered X-ray is obtained from the peak voltage, the diffraction angle of the spectral crystal is calculated, the spectral crystal and the reflection X-ray detector are moved to the diffraction angle, and the energy corresponding to the incident X-ray is reflected. A laminated thin film inspection apparatus characterized by measuring only X-rays. The laminated thin film inspection apparatus according to claim 5,
2. The multilayer thin film inspection apparatus according to claim 1, wherein the spectral crystal has a curved structure, and a diffraction width of the spectral crystal is 300 eV or less. The laminated thin film inspection apparatus according to claim 1 or 4,
An apparatus for inspecting a laminated thin film, wherein an angle formed by a scattering vector of the spectroscopic element and a plane of the condensing element is in a range of ± 45 °.

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