JP2017142143A - Fluorescence measuring apparatus and fluorescence measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence measuring apparatus capable of accurately and efficiently performing an inspection of a test object such as a semiconductor substrate, and a fluorescence measuring method.SOLUTION: A fluorescence measuring apparatus comprises: an illuminating device 3 for irradiating a test object with light rays; an imaging part for imaging the test object irradiated with the light rays; and a data processing part for performing processing based on imaging data in the imaging part. The illuminating device includes: a laser light source 30 for emitting laser light; and an integrating sphere 31 for allowing the laser light from the laser light source to be diffusely reflected inside to emit it toward the test object as a light flux. The light rays with which the illuminating device irradiates the test object may be parallel light. The illuminating device preferably has an adjustment mechanism 32 for adjusting an open angle between the light fluxes emitted from the integrating sphere. The adjustment mechanism may include an object lens 37 that can come close to and separate from the integrating sphere. A determination part may be provided that determines whether the test object has a defect or not on the basis of a processing result in the data processing part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fluorescence measuring apparatus and a fluorescence measuring method using fluorescence when a test object such as a semiconductor substrate is irradiated with light.

  In the manufacturing process of a semiconductor wafer, it is important to reduce defects in the semiconductor wafer in order to improve the yield rate and reduce characteristic defects. Of the defects in the semiconductor wafer, if the process proceeds without being detected until the semiconductor wafer characteristic inspection step and the appearance inspection step, which are the final steps of the wafer process, the manufacturing efficiency of the semiconductor element only decreases. Not only that, the non-defective product ratio of the semiconductor element is also reduced. For this reason, it is desirable to appropriately find internal defects in the semiconductor wafer as early as possible in the manufacturing process of the semiconductor wafer.

  As a method for inspecting a defect of a semiconductor wafer, non-destructive inspection is generally used. As this nondestructive inspection, there is a method of evaluating based on light emission by luminescence when a semiconductor wafer is irradiated with laser light (see, for example, Patent Documents 1 and 2). The methods described in Patent Documents 1 and 2 are methods for detecting a substrate defect based on luminescence emission when a semiconductor substrate is irradiated with a light beam of a laser beam having a wavelength of 400 nm or less as excitation light.

  However, in the inspection methods described in these Patent Documents 1 and 2, the laser beam is irradiated on the semiconductor substrate by spot irradiation with the laser beam on the surface of the semiconductor substrate, and the irradiation point is set in two directions relative to the semiconductor substrate. This is done by scanning. In this method of scanning the spot irradiated point, a relatively long time is required to irradiate the entire surface of the semiconductor substrate with laser light, and therefore a relatively long time is required for the inspection of the semiconductor substrate. This is disadvantageous in terms of inspection efficiency.

JP 2007-258567 A JP 2008-198913 A

  The present inventor has examined the improvement of inspection efficiency. As a result, the beam diameter of the light emitted from the laser light source is expanded, and the inspection target in the irradiation region is irradiated with the expanded light beam. The idea was to detect the emitted light at once. However, when the light emitted from the laser light source is enlarged by a lens and irradiated onto an inspection object, and image data of the irradiated region is acquired, it has been found that speckle is generated in the image data. For this reason, it has been found that when the light beam expanded by the lens as described above is irradiated onto the inspection object, an accurate inspection cannot be performed. This is considered to be because the light emitted from the laser light source has high coherence, so that the luminous flux expanded by the lens as described above has different intensities in each part of the irradiation region.

  Accordingly, the present invention has been made in view of these disadvantages, and an object thereof is to provide a fluorescence measuring apparatus and a fluorescence measuring method capable of efficiently performing an accurate inspection of an inspection object.

The present invention made to solve the above problems
An illumination device for irradiating the inspection object with light rays;
An imaging unit for imaging the inspection object irradiated with the light beam;
A fluorescence measurement device comprising a data processing unit that performs processing based on imaging data in the imaging unit,
The illumination device is a fluorescence measurement device including a laser light source that emits laser light and an integrating sphere that diffuses and reflects the laser light from the laser light source and emits the light toward the inspection target as a light beam.

  Since the fluorescence measuring apparatus uses a light beam emitted from an integrating sphere instead of the conventional spot irradiation as a light beam to irradiate the inspection object, it is possible to irradiate a relatively wide area of the inspection object at once with this light beam. it can. Therefore, the time required for irradiating the entire inspection object with light rays can be shortened as compared with the conventional spot irradiation apparatus, and the inspection time can be shortened. Further, since the fluorescence measuring apparatus uses a low-coherence light beam obtained by diffusing and reflecting the laser light from the laser light source in the integrating sphere as the irradiation light, uniform irradiation is performed in each part of the irradiation region once. As a result, an accurate inspection of the inspection object can be performed.

  The light beam applied to the inspection object by the illumination device may be parallel light. By irradiating the inspection target with parallel light in this way, uniform irradiation can be performed in the irradiation region of the inspection target, and the defect of the inspection target can be accurately detected.

  The illumination device preferably has an adjustment mechanism for adjusting an opening angle of a light beam emitted from the integrating sphere. By having the adjustment mechanism in this way, it becomes possible to adjust the beam diameter of the light beam irradiated on the surface of the inspection object. Therefore, by adjusting the light beam diameter of the irradiated light beam by the adjustment mechanism, it becomes easy to irradiate the light beam all over the surface to be inspected. In addition, it is possible to irradiate the entire surface with light with a uniform amount of light even for inspection objects of different sizes simply by adjusting the beam diameter of the irradiated light with the adjusting mechanism. Therefore, the fluorescence measuring apparatus can cope with inspections of inspection objects of different sizes, and even in the case of inspecting inspection objects of a relatively large size, it can be accurately and advantageously accurately in a short time with a simple configuration. Inspection can be performed.

  The adjustment mechanism may include an objective lens that is disposed on the optical path of the light emitted from the integrating sphere and is capable of approaching and separating from the integrating sphere. Since such an adjustment mechanism can be configured inexpensively and easily, the fluorescence measuring apparatus can cope with inspection of inspection objects having different sizes advantageously in terms of cost.

  The fluorescence measurement device preferably includes a determination unit that determines the presence or absence of the defect to be inspected based on a processing result in the data processing unit. By providing the determination unit in this way, the fluorescence measurement device can be applied to detection of the presence or absence of a defect to be inspected. In addition, the determination unit is configured to determine the presence or absence of the defect to be inspected based on the emission light from the fluorescence to be inspected, and thus preferably detects the defect to be inspected, particularly the defect of the semiconductor substrate as the inspection object. be able to.

  The detection unit and the data processing unit may be constituted by a CCD camera. By configuring the detection unit and the data processing unit with the CCD camera in this way, it is possible to appropriately detect the emitted light by the fluorescence using an existing apparatus. Therefore, the fluorescence measuring apparatus can obtain a sensitivity sufficient for measuring the emitted light by the fluorescence with a simple configuration, and can reduce the manufacturing cost of the measuring apparatus.

  The peak wavelength of the laser light emitted from the laser light source is preferably 350 nm or more and 790 nm or less. By using a laser beam having a peak wavelength in the above wavelength range, information such as the presence or absence of impurities and lattice defects in the surface layer to be inspected such as a semiconductor substrate can be appropriately obtained from fluorescence. Therefore, the fluorescence measuring apparatus can appropriately inspect a semiconductor substrate for defects and the like. In addition, laser light having a peak wavelength in the above wavelength range can be emitted using an existing laser light source. Therefore, the fluorescence measuring apparatus can obtain fluorescence using an existing laser light source without using a special laser light source. As a result, the fluorescence measuring apparatus can be advantageously realized in terms of manufacturing cost with a simple configuration.

Further, the present invention is a fluorescence measurement method for irradiating a test object with light, imaging the irradiated test object, and performing data processing based on the captured data,
This is a fluorescence measurement method using a light beam obtained by diffusing and reflecting a laser beam from a laser light source inside an integrating sphere as an irradiation beam to the inspection object.

  Since the fluorescence measurement method uses a low-coherence light beam diffusely reflected inside the integrating sphere as an irradiation light to the semiconductor substrate, as in the fluorescence measurement apparatus, when the laser light is spot-irradiated on the surface to be inspected. Compared to this, it is possible to secure a large light irradiation area for the surface of the inspection object. As a result, according to the fluorescence measuring method, it is possible to accurately inspect the inspection object with a simple configuration and advantageously in a short time and in a cost.

  Note that “fluorescence” in the present invention includes not only narrow-sense fluorescence, which is emission associated with deactivation from an excited singlet, but also phosphorescence, which is emission associated with deactivation from a triplet. Further, the “parallel light” in the present invention is an aggregate of light rays parallel to the optical axis, includes perfect parallel light, and further includes the maximum relative angle of light rays that constitute the light rays to be inspected (the above-mentioned irradiation light rays). Light having an angle difference of 5 ° or less).

  According to the present invention, a light beam having a relatively low coherence emitted from an integrating sphere is irradiated onto the inspection object as described above, so that a relatively wide area can be irradiated at a time. It is possible to perform an accurate inspection efficiently.

It is a schematic diagram of the photoluminescence measuring apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the principal part of the photo-luminescence measuring apparatus of FIG. It is a schematic diagram which shows the principal part of the photoluminescence measuring apparatus which concerns on the 2nd Embodiment of this invention. 4A is a perspective view showing an irradiation light selection member in the photoluminescence measuring apparatus of FIG. 3, and FIG. 4B is a cross-sectional view of the irradiation light selection member shown in FIG. (C) is sectional drawing which shows the other example of an irradiation light selection member. It is a schematic diagram which shows the principal part of the photoluminescence measuring apparatus which concerns on the 3rd Embodiment of this invention. It is a top view which shows typically the irradiation light selection member in the photo-luminescence measuring apparatus of FIG. It is a schematic diagram which shows the principal part of the photoluminescence measuring apparatus which concerns on the 4th Embodiment of this invention.

  Hereinafter, the fluorescence measurement apparatus and measurement method of the present invention will be described as first to fourth embodiments with reference to the drawings as appropriate, taking the photoluminescence measurement apparatus and measurement method as examples.

[First Embodiment]
≪Photoluminescence measuring device≫
A photoluminescence measuring apparatus 1 shown in FIG. 1 is used for non-destructive inspection of a semiconductor substrate 2. The photoluminescence measuring device 1 includes a lighting device 3, an imaging unit (CCD camera 4), and a personal computer 5.

<Semiconductor substrate>
The semiconductor substrate 2 is to be inspected by the photoluminescence measuring device 1. The semiconductor substrate 2 is not particularly limited, and a semiconductor substrate having a diameter of 50 mm to 300 mm and a thickness of 0.5 mm to 1.0 mm can be used. As such a semiconductor substrate 2, for example, SEMI (Semiconductor Equipment and Materials International) or JEITA (Japan Electronics and Information Technology) (thickness of a semiconductor substrate having a diameter of a silicon semiconductor and a thickness of a semiconductor substrate having a thickness of a semiconductor substrate having a thickness of a semiconductor substrate). , Silicon carbide substrate, and sapphire substrate. Examples of the compound semiconductor substrate include a gallium nitride substrate, a gallium phosphide substrate, an indium phosphide substrate, and a potassium arsenide substrate. Among these semiconductor substrates, the photoluminescence measuring device 1 is suitably used for inspection of a gallium nitride substrate formed with a diameter of 100 mm (4 inches) to 200 mm (8 inches) and a thickness of 520 mm to 725 mm.

<Lighting device>
The illumination device 3 irradiates the semiconductor substrate 2 with light rays. The illumination device 3 includes a laser light source 30, an integrating sphere 31, and an adjustment mechanism 32.

(Laser light source)
The laser light source 30 emits laser light. Although it does not specifically limit as a peak wavelength of a laser beam, 350 nm or more and 790 nm or less are preferable. According to the laser beam having a peak wavelength in such a wavelength range, information such as the presence or absence of impurities and lattice defects in the surface layer of the semiconductor substrate 2 can be appropriately obtained from the photoluminescence emission. Therefore, the photoluminescence measuring device 1 can appropriately inspect the semiconductor substrate 2 for defects and the like. In addition, laser light having a peak wavelength in the above wavelength range can be emitted using an existing laser light source. Therefore, the photoluminescence measuring device 1 can obtain photoluminescence emission using an existing laser light source without using a special laser light source. As a result, the photoluminescence measuring device 1 can be advantageously realized in terms of manufacturing cost with a simple configuration.

The output of the laser beam is not particularly limited, but this output is preferably 5 mW or more, and more preferably 10 mW or more. On the other hand, this output is preferably 500 mW or less, and more preferably 300 mW or less. Further, the intensity of the laser light (the output of the laser light per unit area) is preferably 0.1 mW / mm ² or more, and more preferably 0.2 mW / mm ² or more. On the other hand, the intensity of the laser beam is preferably from 10 mW / mm ² or less, more preferably 6.5 mW / mm ^2. The laser light may be a continuous wave or a pulse wave, but a continuous wave is preferable because it has little temporal fluctuation and is excellent in temporal stability.

  The emission time of the laser beam, that is, the irradiation time (exposure time) of the light beam emitted to the semiconductor substrate 2 is not particularly limited, but this exposure time is preferably 0.1 seconds or more, and 0.5 seconds or more. Is more preferable. The exposure time is preferably 60 seconds or less, and more preferably 10 seconds or less. If the output of laser light or the exposure time is smaller than the above lower limit value, there is a possibility that sufficient data for measurement cannot be obtained. On the other hand, if the output of laser light or the exposure time is longer than the upper limit, the apparatus may be expensive and the inspection time may be increased.

The laser light source 30 is not particularly limited, and various known light sources can be used. The laser light source 30 may be selected according to the type of the measurement target 2, the type of the measurement target light, and the like. Among these, those capable of emitting laser light having a peak wavelength of 350 nm or more and 790 nm or less are preferable. Examples of the laser light source 30 include a gas laser oscillation device such as an Ar laser oscillation device and an excimer XeF oscillation device, a YAG THG (third harmonic) laser oscillation device, a YAG SHG (second harmonic) laser oscillation device, Examples include YVO ₄ THG (third harmonic) laser oscillation device, YLF THG (third harmonic) laser oscillation device, supercontinuum light source, and semiconductor laser.

(Integrating sphere)
The integrating sphere 31 diffuses and reflects the laser beam from the laser light source 30 and emits it as a light beam. The integrating sphere 31 includes an internal space 33, an entrance port 34, and an exit port 35. By diffusing and reflecting the laser beam by the integrating sphere 31, the coherence of the laser beam can be reduced and emitted.

  The internal space 33 is defined in a spherical shape by a reflective surface 36 having a high reflectance. The reflection surface 36 is constituted by the surface of a reflection layer formed as a sintered body or a coating film, for example, and the light incident on the reflection layer is irregularly reflected (diffuse reflection). As the reflection layer, a sintered body having a high coherence reduction ability is preferably used because a part of the light ray penetrates slightly into the reflection layer and is reflected (reflected after being slightly incident on the inner side of the reflection layer rather than the reflection surface interface). The sintered body may be either a resin sintered body or a ceramic sintered body. Examples of the powder material for forming the sintered body include resins such as PTFE (tetrafluoroethylene), and inorganic oxides such as magnesium oxide, aluminum oxide, and zinc oxide. Among them, PTFE is preferable. As a sintered body of PTFE powder, for example, Spectralon (registered trademark) manufactured by Labs Fair Co., Ltd. can be used. Furthermore, although it does not specifically limit as thickness of the reflection layer comprised from the said sintered compact, It is preferable that it is 0.1 mm or more, It is more preferable that it is 1 mm or more, It is further more preferable that it is 10 mm or more. In addition, the upper limit of this thickness is not specifically limited, For example, it is 20 mm. Moreover, the coating film as a reflective layer is formed with the coating agent containing reflective agents, such as magnesium oxide, aluminum oxide, barium sulfate, magnesium sulfate, zinc oxide, for example. The reflective layer may be formed by applying metal plating such as gold plating.

  The diameter of the internal space 33 is not particularly limited, but is preferably 5 cm or more, and more preferably 10 cm or more. Further, the diameter of the internal space 33 is preferably 50 cm or less, and more preferably 20 cm or less. If the diameter of the internal space 33 is smaller than the lower limit value, it is difficult to ensure a sufficiently large beam diameter of the light beam applied to the semiconductor substrate 2. On the other hand, if the diameter of the internal space 33 exceeds the upper limit, the manufacturing cost of the integrating sphere 31 increases, and the attenuation amount of the diffusely reflected light in the internal space 33 increases, which may reduce the amount of emitted light.

  The incident port 34 is for introducing laser light emitted from the laser light source 30 into the internal space 33, and is formed in a circular shape, for example. The size of the entrance 34 may be appropriately set according to the beam diameter of the laser light from the laser light source 30, and is not particularly limited.

  The exit 35 emits diffusely reflected light in the internal space 33 of the integrating sphere 31 to the outside from the internal space 33, and is formed in a circular shape, for example. What is necessary is just to set the magnitude | size of the exit 35 suitably according to the diameter of the light beam which should be radiate | emitted from the integrating sphere 31, light intensity, etc. FIG.

  The aperture ratio in the integrating sphere 31 favorably improves the throughput in the integrating sphere 31 while ensuring the uniformity and low coherence of the light beam emitted from the integrating sphere 31 (exit port 35) and thus the light beam applied to the semiconductor substrate 2. In order to ensure, for example, 1/20 or less. The aperture ratio is preferably 1/40 or less, more preferably 1/60 or less, and even more preferably 1/100 or less. Here, the aperture ratio is defined as the ratio of the aperture area to the inner surface area of the integrating sphere 31. Specifically, the aperture ratio N is expressed as N = (s1 + s2) / S, where S is the inner surface area of the integrating sphere 31, S1 is the opening area of the incident port 34, and S2 is the opening area s2 of the exit port 35. .

  In such integrating sphere 31, the laser light incident from the entrance 34 is repeatedly diffused and reflected by the reflecting surface 36, and the internal space 33 has a substantially uniform brightness. As a result, the light emitted from the exit port 35 is emitted as a light beam with reduced coherence and having an opening angle corresponding to the diameter of the integrating sphere 31 and the exit port 35. The light beam thus uniformized can irradiate the semiconductor substrate 2 with a light beam with a uniform light amount. As described above, the photoluminescence measuring apparatus 1 can irradiate the semiconductor substrate 2 with a light beam with reduced coherence with a uniform amount of light, so that speckle is generated in the image data due to the scattered light from the semiconductor substrate 2. As a result, the semiconductor substrate 2 can be accurately inspected based on the light emitted from the semiconductor substrate 2 by photoluminescence emission.

(Adjustment mechanism)
The adjustment mechanism 32 adjusts the opening angle of the light beam emitted from the integrating sphere 31 to adjust the irradiation area on the surface of the semiconductor substrate 2. The adjustment mechanism 32 includes an objective lens 37 and an actuator 38.

  The objective lens 37 is a lens that collimates the light beam applied to the semiconductor substrate 2. The objective lens 37 has light transparency, and is formed of, for example, a transparent resin or transparent glass. The dimensions of the objective lens 37 may be appropriately set according to the diameter of the light beam emitted from the integrating sphere 31, the distance D1 between the exit port 35 of the integrating sphere 31 and the center of the objective lens 37, the dimensions of the semiconductor substrate 2, and the like. . The diameter of the objective lens 37 is not particularly limited, but is, for example, 1 cm or more and 20 cm or less, and preferably 3 cm or more and 10 cm or less.

  Such an objective lens 37 is disposed on the optical path of the light emitted from the integrating sphere 31. More specifically, the objective lens 37 is disposed at a position where the optical axis L of the light emitted from the integrating sphere 31 coincides with or substantially coincides with the optical axis (main axis) of the lens.

  The objective lens 37 is disposed at a position where the light beam applied to the semiconductor substrate 2 is parallel light. In this way, the parallel irradiation of the light beam by the objective lens 37 enables uniform irradiation in the irradiation region of the semiconductor substrate 2.

  The illuminating device 3 is configured to irradiate a light beam so that the optical axis is perpendicular to the semiconductor substrate 2. For this reason, it becomes easy to distinguish and detect the emitted light by photoluminescence emission, and as a result, according to the photoluminescence measuring apparatus 1, it becomes possible to detect the defect of the semiconductor substrate 2 with high accuracy. .

  The actuator 38 moves the objective lens 37 along the optical axis L of the light beam from the integrating sphere 31. That is, the objective lens 37 can be moved close to and away from the integrating sphere 31 by the actuator 38. As the actuator 38, a known mechanism, for example, an electric type, a magnetic type, a mechanical type, or a combination thereof can be used. The actuator 38 is controlled by the personal computer 5. That is, the position of the objective lens 37 (distance D1 and distance D2) is regulated by controlling the operation of the actuator 38 by the personal computer 5. When the mechanical actuator 38 is employed, the position of the objective lens 37 may be manually adjusted.

  In the adjusting mechanism 32, the opening angle of the light beam transmitted through the objective lens 37 can be increased by bringing the objective lens 37 close to the integrating sphere 31 (by decreasing the distance D1 and increasing the distance D2). . On the other hand, in the adjustment mechanism 32, by separating the objective lens 37 from the integrating sphere 31 (by increasing the distance D1 and decreasing the distance D2), the opening angle of the light beam transmitted through the objective lens 37 is decreased. can do. As described above, the adjustment mechanism 32 can adjust the opening angle of the light beam transmitted through the objective lens 37 by regulating the position of the objective lens 37, and therefore adjust the light beam diameter of the light beam that irradiates the surface of the semiconductor substrate 2. Is possible. Therefore, by adjusting the beam diameter of the irradiation light beam by the adjustment mechanism 32, it becomes easy to irradiate the light beam with a uniform light amount all over the surface of the semiconductor substrate 2. In addition, it is possible to irradiate the entire surface of the semiconductor substrate 2 with different sizes all together by simply adjusting the beam diameter of the irradiated light beam by the adjusting mechanism 32. Therefore, the photoluminescence measuring apparatus 1 can cope with the inspection of the semiconductor substrates 2 having different sizes, and even in the case of inspecting the semiconductor substrate 2 having a relatively large size, it can be quickly and cost-effectively with a simple configuration. Advantageously, an accurate inspection can be performed.

  Further, the adjustment mechanism 32 does not necessarily need to be configured so that the objective lens 37 can be moved. For example, in the photoluminescence measuring apparatus 1 used for the inspection of the single-sized semiconductor substrate 2, the position of the objective lens 37 is fixed. Also good. In this case, the objective lens 37 is preferably fixed at a position where the semiconductor substrate 2 can be irradiated with parallel light.

  Further, as the lens of the adjusting mechanism 32, a collimating lens may be used instead of the objective lens 37. Further, a plurality of different types of lenses such as an objective lens and a collimator lens may be combined, or a plurality of lenses of the same type may be combined and used as the lens system of the adjustment mechanism 32. Also in the photoluminescence measuring apparatus 1 employing such an adjustment mechanism 32, the position of the lens system may be fixed. In this case, in order to enable inspection of the semiconductor substrate 2 having different dimensions, the opening angle of the light beam emitted from the lens system is set so that at least one lens constituting the lens system can be moved close to and away from the integrating sphere 31. It is preferable that the configuration is adjusted. The lens system preferably includes an aberration correction lens. When the lens system includes the aberration correction lens, it is possible to suppress the occurrence of blurring at the peripheral portion of the captured image and to capture a beautiful image with little blurring.

<Imaging unit>
The imaging unit images the semiconductor substrate 2 irradiated with the light beam by the irradiation device 3. The imaging unit is not particularly limited, but for example, a CCD camera 4 such as a cooled CCD camera is used. In the present embodiment, the imaging unit obtains information necessary for the inspection of the semiconductor substrate 2 based on the emitted light by the luminescence emission when the semiconductor substrate 2 is irradiated with light (excitation light). As shown in FIG. 2, the CCD camera 4 includes a detection unit 40, a data processing unit 41, and an output unit 42. Further, the CCD camera 4 may be one having an aberration correction lens (CCTV lens) attached thereto. In the CCD camera 4 provided with such an aberration correction lens, it is possible to suppress the occurrence of blurring at the peripheral portion of the captured image and to capture a beautiful image with little blurring.

  The detection unit 40 detects radiation emitted by luminescence emission when the semiconductor substrate 2 is irradiated with a light beam, and is configured by a two-dimensional CCD image sensor. Further, a filter F such as an interference filter may be disposed between the detection unit 40 and the semiconductor substrate 2. Since this filter F can reduce the amount of noise components detected by the detection unit 40, the detection sensitivity can be increased. Such a filter F may be integrated with the CCD camera 4.

  The data processing unit 41 performs data processing based on the detection result of the detection unit 40, and includes, for example, a CPU, a ROM, and a RAM.

  The output unit 42 outputs the processing result in the data processing unit 41 to the personal computer 5. The output unit 42 has an external connection connector (not shown), and can output data to the personal computer 5. Examples of the external connection connector include a 9-pin serial port, a 25-pin parallel port, a 4 / 6-pin high-speed serial port, a USB (Universal Serial Bus), a PS / 2 connector, a VGA terminal, and a DVI port.

  As described above, the CCD camera 4 includes the detection unit 40 and the data processing unit 41. That is, since the detection unit 40 and the data processing unit 41 are configured by a CCD camera, the photoluminescence measuring apparatus 1 can appropriately detect the emitted light by the photoluminescence emission using the existing CCD camera 4. Therefore, the photoluminescence measuring device 1 can obtain a sensitivity sufficient to measure the emitted light by the photoluminescence emission with a simple configuration, and can reduce the manufacturing cost of the measuring device.

<Personal computer>
The personal computer 5 displays an image of the semiconductor substrate 2 based on data from the CCD camera 4 and controls the laser light source 30 and the illumination device 3. The personal computer 5 is a desktop type and includes a main body 50, a display 51, and a keyboard 52. As the personal computer 5, a commercially available general-purpose product can be used, and a laptop personal computer can also be used.

  The main body 50 has a function as a determination unit 53 that determines the presence / absence of a defect in the semiconductor substrate 2 based on the processing result in the data processing unit 41. The main body 50 includes a CPU, a ROM, and a RAM, and a function as the determination unit 53 is given by these.

  The display 51 displays an image of the semiconductor substrate 2 and is configured by, for example, a liquid crystal display device. In addition to the image of the semiconductor substrate 2, the display 51 can display measurement conditions, setting images of the laser light source 30 and the illumination device 3, and the like.

  The keyboard 52 is for inputting information necessary for the operation of the personal computer 5.

  By providing the determination unit 53, the photoluminescence measuring device 1 can detect the presence or absence of defects in the semiconductor substrate 2 as well as imaging the semiconductor substrate 2. Moreover, since the determination part 53 determines the presence or absence of the defect of the semiconductor substrate 2 based on the emitted light by photoluminescence light emission, it can detect the defect of the semiconductor substrate 2, especially an internal defect suitably.

  As described above, since the photoluminescence measuring apparatus 1 uses the light beam emitted from the integrating sphere 31 instead of the conventional spot irradiation as the light beam to be irradiated on the semiconductor substrate 2, a relatively wide area of the semiconductor substrate 2 is generated by this light beam. Can be irradiated at once. As a result, the time required for irradiating the entire semiconductor substrate 2 with light rays can be shortened compared to a conventional spot irradiation apparatus, and the inspection time can be shortened. Further, since the photoluminescence measuring apparatus 1 uses a light beam having a low coherence obtained by diffusing and reflecting the laser light from the laser light source in the integrating sphere 31 as the irradiation light, it is uniform in each part of the irradiation region once. Since irradiation can be performed, generation of speckles in the image data due to scattered light from the semiconductor substrate 2 can be suppressed, and as a result, accurate inspection of the semiconductor substrate 2 can be performed easily and reliably.

≪Photoluminescence measurement method≫
A photoluminescence measurement method, which is an example of the fluorescence measurement method of the present invention, irradiates a semiconductor substrate 2 to be inspected with irradiation light, images the irradiated semiconductor substrate 2, and performs data processing based on the captured data. This is a method for measuring photoluminescence. As the irradiation light to the semiconductor substrate 2, a light beam obtained by diffusing and reflecting the laser light from the laser light source 30 inside the integrating sphere 31 is used. Such a photoluminescence measuring method can be realized by the photoluminescence measuring device 1.

  In this photoluminescence measuring method, a light beam having a low coherence obtained by diffusing and reflecting the laser light from the laser light source 30 in the integrating sphere 31 is used as a light beam to be irradiated onto the semiconductor substrate 2, so that the inspection time can be shortened. In addition, it is possible to suppress speckles from being generated in the image data by performing uniform irradiation in each part of the irradiation region once, and it is possible to accurately inspect the semiconductor substrate 2.

[Second Embodiment]
The photoluminescence measuring device 6 shown in FIGS. 3 and 4 has basically the same configuration as the photoluminescence measuring device 1 shown in FIG. 1, but the configuration of the adjusting mechanism 61 of the illumination device 60 is a photoluminescence measurement. Different from the device 1. In FIG. 3, elements similar to those of the photoluminescence measuring apparatus 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant description below is omitted.

  The adjustment mechanism 61 includes a light beam adjustment member 62 that can be moved close to and away from the integrating sphere 31 by an actuator 38. The light beam adjusting member 62 adjusts the diameter and the opening angle of the light beam emitted from the illumination device 60, and has a light transmission region 63 and a light non-transmission region 64 as shown in FIGS. Yes.

  The light transmission region 63 is a region through which the light beam emitted from the integrating sphere 31 is transmitted, and is formed in a circular shape by a transparent material such as a transparent resin. On the other hand, the light non-transmission region 64 is a region that restricts the transmission of the light beam emitted from the integrating sphere 31 and is formed so as to surround the periphery of the light transmission region 63 with an opaque material such as black resin.

  In such an illuminating device 60, the light beam emitted from the integrating sphere 31 is limited in transmission of light in the outer peripheral portion corresponding to the light non-transmissive region 64 in the adjustment mechanism 61, and the region corresponding to the light transmissive region 63. Light is selectively transmitted. As a result, the luminous flux emitted from the integrating sphere 31 has a smaller luminous flux diameter when passing through the luminous flux adjusting member 62 and a smaller opening angle than the luminous flux reaching the luminous flux adjusting member 62. In the lighting device 60, the diameter and opening angle of the light beam emitted from the lighting device 60 can be adjusted by adjusting the position of the light beam adjusting member 62 using the actuator 38. Therefore, the photoluminescence measuring device 6 including the illumination device 60 can achieve the same effect as the photoluminescence measuring device 1 shown in FIGS. 1 and 2.

  The light transmission region 63 is not necessarily formed of a transparent material as long as the light beam emitted from the integrating sphere 31 can be transmitted. For example, the light transmission region 63 may be formed of a material that selectively transmits only light having the wavelength of the light emitted from the integrating sphere 31 (the wavelength of the laser light emitted from the laser light source 30). It may be formed. On the other hand, the light-impermeable region 64 is not necessarily formed of a black material as long as the light flux emitted from the integrating sphere 31 can be limited. That is, the light transmission region 63 and the light non-transmission region 64 may be appropriately selected depending on the wavelength of the light emitted from the integrating sphere 31.

  Further, instead of the light flux adjusting member 62, a light flux adjusting member 65 shown in FIG. The light flux adjusting member 65 is obtained by forming a light shielding portion 67 on one surface of a translucent member 66. The light shielding portion 67 has a circular through hole 68. The translucent member 66 is formed of a transparent material such as a transparent resin, and the light shielding portion 67 is formed of a black material such as a black resin. In addition, regarding the translucent member 66 and the light shielding portion 67 of the light beam adjusting member 65, the same design change as the light transmitting region 63 and the light non-transmitting region 64 of the light beam adjusting member 62 shown in FIG.

  In such a light flux adjusting member 65, the light flux that has passed through the through hole 68 passes through the translucent member 66, while the light shielding portion 67 restricts the transmission of the light flux. That is, the light beam emitted from the integrating sphere 31 and emitted from the adjusting mechanism 61 has a smaller light beam diameter when passing through the light beam adjusting member 65 and has a smaller opening angle than the light beam reaching the light beam adjusting member 62. The

[Third Embodiment]
The photoluminescence measuring device 7 shown in FIGS. 5 and 6 has basically the same configuration as the photoluminescence measuring device 1 shown in FIG. 1, but the configuration of the adjustment mechanism 71 of the illumination device 70 is a photoluminescence measurement. Different from the device 1. In FIG. 5, elements similar to those of the photoluminescence measuring device 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant description below is omitted.

  The adjustment mechanism 71 includes a light beam adjustment element 72 fixed to the exit port 35 of the integrating sphere 31. The light beam adjusting element 72 adjusts the diameter and the opening angle of the light beam emitted from the illumination device 70. For example, the light beam adjusting element 72 is a transmissive display element such as a liquid crystal display element having a plurality of display elements or an organic EL display element. It is configured. That is, the light flux adjusting element 72 provides the light transmitting region 73 and the light non-transmitting region 74 as shown in FIGS. 6A and 6B by controlling the light transmitting state of each display element. In addition, the size of the light transmission region 73 can be adjusted. The light opaque region 74 can be realized by, for example, black display.

  Also in such an illuminating device 70, the light beam emitted from the integrating sphere 31 is limited to transmit light in the outer peripheral portion corresponding to the light non-transmissive region 74, and the light in the region corresponding to the light transmissive region 73 is selective. To penetrate. As a result, the luminous flux emitted from the adjusting mechanism 71 has a smaller luminous flux diameter and a smaller opening angle than when entering the adjusting mechanism 71.

  The light beam adjusting member 72 is not necessarily fixed to the exit port 35 of the integrating sphere 31 and may be disposed on the optical path of the light beam from the integrating sphere 31 at a position away from the integrating sphere 31. It may be possible to approach and separate from 31.

[Fourth Embodiment]
The photoluminescence measuring device 8 shown in FIG. 7 has basically the same configuration as the photoluminescence measuring device 1 shown in FIG. 1, but the internal structure of the integrating sphere 81 of the illumination device 80 is the photoluminescence measuring device 1. Is different. In FIG. 7, the same elements as those in the photoluminescence measuring apparatus 1 shown in FIG.

  The integrating sphere 81 shown in FIG. 7 suppresses that the reflected light whose number of reflections is equal to or less than a predetermined number of the reflected light reflected by the reflection surface 36 of the laser light incident from the incident port 34 is emitted from the emission port 35. The light shielding member 82 is provided. The predetermined number of times is preferably twice. Specifically, the light shielding member 82 is formed of, for example, a plate-like member, and is referred to as an opposing surface 83 (hereinafter referred to as a first opposing surface 83) of the entrance 34 through which the laser light incident into the integrating sphere 81 is incident. And a facing surface 84 (hereinafter, also referred to as a second facing surface 84) of the emission port 35. Thereby, the light beam traveling from the incident port 34 and traveling toward the second facing surface 84 out of the laser light reflected by the first facing surface 83 is shielded by the light shielding member 82. By providing the light blocking member 82 in this way, the laser light emitted from the emission port 35 can be reflected at least three times in the integrating sphere 81, so that the coherence of the laser light can be more reliably reduced. Can be emitted.

  The surface of the light shielding member 82 is preferably formed with a high reflectance like the reflective surface 36. Thereby, it is possible to suppress the incident light from the incident port 35 from being attenuated while being diffusely reflected inside the integrating sphere 81, and to suppress a decrease in utilization efficiency of the incident light from the incident port 35. Such a light shielding member 82 can be obtained by forming at least the surface layer as a reflection layer that irregularly reflects (diffusely reflects) light incident on the surface layer. This reflective layer can be obtained as a sintered body or a coating film by the same method as the reflective layer of the integrating sphere 31 described above.

[Modification]
The present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the technical idea of the present invention. For example, the adjustment mechanism in the photoluminescence measuring device is not an essential configuration and may be omitted.

  In place of the cooled CCD camera as the imaging unit, various devices such as a room temperature CCD camera and a camera incorporating a CMOS sensor as a photoluminescence emission detecting unit can be used. Further, it is not always necessary to use a photoluminescence emission detection unit and a data processing unit that are incorporated in an imaging apparatus such as a CCD camera. Further, in the above embodiment, the description has been given of the case where the imaging unit obtains information necessary for the inspection of the semiconductor substrate 2 based on the emitted light by the luminescence emission when the semiconductor substrate 2 is irradiated with the light beam (excitation light). The invention is not limited to this. Specifically, for example, the imaging unit can image the reflected light of the semiconductor substrate irradiated by the light beam emitted from the integrating sphere, and inspect based on the imaging data. In addition, the inspection target of the photoluminescence measurement apparatus which is the fluorescence measurement apparatus of the present invention may be other than the semiconductor substrate, and the fluorescence inspection apparatus can also be used for nondestructive inspection of inspection targets other than the semiconductor substrate.

  In the description of the above embodiment, it has been described that the peak wavelength of the laser beam of the laser light source is preferably 350 nm or more and 790 nm or less, but the present invention is not limited to this. In other words, for example, a laser light source having a peak wavelength of 790 nm or more (for example, a YAG laser having a peak wavelength of 1067 nm) is used, and an infrared camera (for example, a near infrared camera using an indium, gallium, arsenic sensor, etc.) It is also possible to receive light.

  The determination unit is not necessarily configured by a personal computer, and may be configured by an information processing apparatus other than the personal computer together with the detection unit and the data processing unit.

  The photoluminescence measuring device does not need to be configured as a separate device that separates the lighting device and the CCD camera from the personal computer, and the functions of the lighting device and the CCD camera and the function of the personal computer can be realized as an integrated device. Good.

  Moreover, in the said embodiment, although the photoluminescence measuring device as the said fluorescence measuring device demonstrated what does not scan a semiconductor substrate, this invention is not necessarily limited to this. That is, even if the fluorescence measuring apparatus has a scanning mechanism for moving the semiconductor substrate relative to the irradiation light beam, it is within the range intended by the present invention. However, it is preferable that the photoluminescence measuring device according to the present invention does not have a scanning mechanism as in the above-described embodiment, thereby simplifying the device and reducing the cost.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescence measuring apparatus and measuring method which can perform the test | inspection of test | inspection objects, such as a accurate semiconductor substrate, efficiently can be provided.

DESCRIPTION OF SYMBOLS 1 Photoluminescence measuring apparatus 2 Semiconductor substrate 3 Illuminating device 30 Laser light source 31 Integrating sphere 32 Adjustment mechanism 33 Internal space 34 Injecting port 35 Ejecting port 36 Reflecting surface 37 Objective lens 38 Actuator 4 CCD camera 40 Detection unit 41 Data processing unit 42 Output unit DESCRIPTION OF SYMBOLS 5 Personal computer 50 Main body 51 Display 52 Keyboard 53 Judgment part 6 Photoluminescence measuring apparatus 60 Illumination apparatus 61 Adjustment mechanism 62 Light flux adjustment member 63 Light transmission area 64 Light non-transmission area 65 Light flux adjustment member 66 Light transmission member 67 Light-shielding part 7 Photo Luminescence measuring device 70 Illuminating device 71 Adjustment mechanism 72 Light flux adjusting element 73 Light transmitting region 74 Light non-transmitting region 8 Photoluminescence measuring device 80 Illuminating device 81 Integrating sphere 82 Light shielding plate L Optical axis F Filter

Claims (8)

An illumination device for irradiating the inspection object with light rays;
An imaging unit for imaging the inspection object irradiated with the light beam;
A fluorescence measurement device comprising a data processing unit that performs processing based on imaging data in the imaging unit,
The fluorescence measurement apparatus, wherein the illumination device includes a laser light source that emits laser light, and an integrating sphere that diffuses and reflects the laser light from the laser light source and emits it toward the inspection object as a light beam.   The fluorescence measuring apparatus according to claim 1, wherein the light beam applied to the inspection object by the illumination device is parallel light.   The fluorescence measuring apparatus according to claim 1, wherein the illumination device includes an adjustment mechanism that adjusts an opening angle of a light beam emitted from the integrating sphere.   The fluorescence measuring apparatus according to claim 3, wherein the adjustment mechanism includes an objective lens that is disposed on an optical path of light emitted from the integrating sphere and is capable of approaching and separating from the integrating sphere.   The fluorescence measuring device according to any one of claims 1 to 4, further comprising a determination unit that determines the presence or absence of the defect to be inspected based on a processing result in the data processing unit.   The fluorescence measuring apparatus according to any one of claims 1 to 5, wherein the detection unit and the data processing unit are configured by a CCD camera.   The fluorescence measuring apparatus according to any one of claims 1 to 6, wherein a peak wavelength of laser light emitted from the laser light source is 350 nm or more and 790 nm or less. A fluorescence measurement method that irradiates a test object with light, images the irradiated test object, and performs data processing based on the captured data,
A fluorescence measurement method using a light beam obtained by diffusing and reflecting a laser beam from a laser light source in an integrating sphere as an irradiation beam to the inspection object.

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