PATTERN INSPECTION APPARATUS AND PATTERN INSPECTION METHOD

A pattern inspection apparatus includes a light source, a detector, and an inspection unit. The light source is configured to emit light toward an inspection target including stacked silicon substrates. The light has a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers. The detector is configured to detect transmitted light of the inspection target or reflected light of the inspection target out of the light emitted from the light source. The transmitted light is light transmitted through the inspection target. The reflected light is light reflected by the inspection target. The inspection unit is configured to perform pattern inspection on the basis of a detection result obtained by the detector.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2021-133293 filed on Aug. 18, 2021, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The technology relates to a pattern inspection apparatus and a pattern inspection method.

Recently, in terms of advancing high integration of integrated circuits, it has reached a physical limit to miniaturize circuits. This has led to stacking of circuits, i.e., three-dimensionalization of circuits. For existing planar circuits, it is possible to perform non-destructive inspection to check defects of all the products to be actually used. For example, Japanese Unexamined Patent Application Publication No. 2013-068551 discloses to apply nanometer-order light to a circuit pattern and to detect a defect of the circuit pattern on the basis of a diffraction image obtained by the nanometer-order light application.

SUMMARY

A pattern inspection apparatus according to an embodiment of the technology includes a light source, a detector, and an inspection unit. The light source is configured to emit light toward an inspection target including stacked silicon substrates. The light has a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers. The detector is configured to detect transmitted light of the inspection target or reflected light of the inspection target out of the light emitted from the light source. The transmitted light is light transmitted through the inspection target. The reflected light is light reflected by the inspection target. The inspection unit is configured to perform pattern inspection on the basis of a detection result obtained by the detector.

A pattern inspection method according to an embodiment of the technology includes: emitting light toward an inspection target including stacked silicon substrates, the light having a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers; detecting transmitted light of the inspection target or reflected light of the inspection target out of the light emitted toward the inspection target, the transmitted light being light transmitted through the inspection target, the reflected light being light reflected by the inspection target; and performing pattern inspection on the basis of a detection result obtained by the detecting.

DETAILED DESCRIPTION

Regarding three-dimensional circuits, difficulty in detecting defects of internal circuit patterns has been an issue. It is desirable to provide a pattern inspection apparatus and a pattern inspection method that each allow for also detecting a defect of an internal circuit pattern in a three-dimensional circuit.

1. Inspection Target

FIG.1illustrates a cross-sectional configuration example of an inspection target10that is an example of an object to be inspected by a pattern inspection apparatus according to an example embodiment of the technology. The inspection target10may be a three-dimensional (3D) chip in which a plurality of large-scale integration (LSI) chips12is stacked on an intermediate substrate11. The number of stacked layers of the LSI chips12is not limited to five layers as illustrated inFIG.1, and may be about ten layers, for example. Provided between the stacked LSI chips12may be a resin filling layer17that fills gaps between the LSI chips12. The resin filling layer17may include, for example, a resin material such as polyimide.

The LSI chips12may each include a Si substrate and an integrated circuit provided thereon. Non-limiting examples of each of the LSI chips12may include a wafer of a 3D flash memory and a camera sensor device. The integrated circuit on the Si substrate of each of the LSI chips12may include, for example but not limited to, a number of complementary metal oxide semiconductors (CMOSs) and a number of wiring patterns.

The LSI chips12may each have, for example but not limited to, a signal through via13and a power-supply through via15that run through the Si substrate. The stacked LSI chips12may be electrically coupled to each other by means of, for example but not limited to, the signal through vias13and signal bumps14. The signal bumps14may be provided between the LSI chips12. The integrated circuits of the respective LSI chips12may receive various signals from outside via, for example but not limited to, the signal through vias13and the signal bumps14. The integrated circuits of the respective LSI chips12may supply various signals to the outside via, for example but not limited to, the signal through vias13and the signal bumps14. The stacked LSI chips12may be electrically coupled to each other by means of, for example but not limited to, the power-supply through vias15and power-supply bridges16. The power-supply bridges16may be provided between the LSI chips12. The power-supply bridges16may each be formed by a method such as electroless plating. The integrated circuits of the respective LSI chips12may receive various power-supply voltages from the outside via, for example but not limited to, the power-supply through vias15and the power-supply bridges16.

The intermediate substrate11may include a wiring layer and a resin layer that supports the wiring layer. The wiring layer may be adapted to, for example, transmit various signals to the stacked LSI chips12or supply various power-supply voltages to the stacked LSI chips12. In one example, the wiring layer may include a passive component such as a resistor. Coupled to the intermediate substrate11may be one or more interface units18. The one or more interface units18may be electrically coupled to the wiring layer of the intermediate substrate11. For example, the one or more interface units18may supply various signals or various power-supply voltages from the outside to the intermediate substrate11, and may supply various signals from the intermediate substrate11to the outside.

With an existing pattern inspection apparatus, in a case where the inspection target is the 3D chip as described above, it is difficult to detect a defect of an internal circuit pattern that is not visible on a chip surface. To address this, the inventor of the application proposes below a pattern inspection apparatus that is able to also detect a defect of an internal circuit pattern that is not visible on a chip surface.

2. First Example Embodiment

Next, a description is given of a pattern inspection apparatus100according to a first example embodiment of the technology.FIG.2illustrates an example of a schematic configuration of the pattern inspection apparatus100. The pattern inspection apparatus100may perform non-destructive inspection of a defect in the inspection target10. For example, as illustrated inFIG.2, the pattern inspection apparatus100may include a stage110and a light source120. The stage110may support the inspection target10. The light source120may emit or apply light La toward the inspection target10on the stage110.

For example, the stage110may suck the inspection target10to thereby fix the inspection target10on an upper surface of the stage110. In addition, in one example, the stage110may include a mechanism that moves a position of the upper surface of the stage110biaxially in a plane parallel to the upper surface of the stage110. In addition, in one example, the stage110may include a mechanism that rotates the upper surface of the stage110azimuthally in the plane parallel to the upper surface of the stage110.

The light source120may include a laser configured to emit the light La and a control circuit that controls light emission of the laser. The control circuit may control the light emission of the laser on the basis of a control performed by a processor160which will be described later. The laser may be configured to emit, as the light La, collimated light having a wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 μm, i.e., a wavelength band of a mid-infrared region. The laser may be, for example, a Tm:YAG laser configured to emit the light La having a constant wavelength of 2.0 μm. The laser is, however, not limited to the Tm:YAG laser. In place of the above-described laser, the light source120may include, for example, a light emitting device, such as a semiconductor laser, configured to emit the light La having a wavelength of 2.0 μm. For example, as illustrated inFIG.3, the above-described mid-infrared region falls within a portion of a light transmission region of the Si substrate. Accordingly, the light La is able to be transmitted through the Si substrate and the inspection target10including the Si substrate.

When the light La is incident on the inspection target10, a portion of the incident light La may be reflected by the inspection target10to become reflected light Lb, which may be incident on a light detector130to be described later; another portion of the incident light La may be transmitted through the inspection target10to become transmitted light Lc, which may be incident on a light detector140to be described later. The inspection target10may be optically regarded as a volume Bragg grating. In this case, the reflected light Lb may be reflected Bragg diffraction light that is a diffraction image generated by light reflected inside the inspection target10. The reflected light Lb may have high diffraction intensity in a particular direction. The transmitted light Lc may be transmitted Bragg diffraction light that is a volume diffraction image generated by the transmitted light of the inspection target10. The transmitted light Lc may also have high diffraction intensity in a particular direction.

As illustrated inFIG.2, the pattern inspection apparatus100may further include, for example but not limited to, the light detectors130and140.

The light detector130may be disposed on an optical path of the reflected light Lb. The light detector130may detect the reflected light Lb on the basis of a control performed by the processor160which will be described later. The light detector130may generate image data Ib on the basis of a result of the detection, i.e., a detection result D1, and supply the generated image data Ib to an inspection unit150which will be described later. Note that, in one example, the light detector130may supply the detection result D1to the inspection unit150.

The light detector140may be disposed on an optical path of the transmitted light Lc. The light detector140may detect the transmitted light Lc on the basis of a control performed by the processor160which will be described later. The light detector140may generate image data Ic on the basis of a result of the detection, i.e., a detection result D2, and supply the generated image data Ic to the inspection unit150which will be described later. Note that, in one example, the light detector140may supply the detection result D2to the inspection unit150.

The light detectors130and140may each include, for example, an image sensor configured to detect light in the above-described mid-infrared region. For example, such an image sensor may include, for each pixel, an InGaAs element that is sensitive to a wavelength band from a visible region to a wavelength of 1.7 μm. Note that the element provided for each pixel is not limited to the InGaAs element.

The pattern inspection apparatus100may further include, for example, a mover121that varies a position of the light source120, a mover131that varies a position of the light detector130, and a mover141that varies a position of the light detector140, as illustrated inFIG.2. The mover121may so set the position of the light source120that the light La emitted from the light source120is incident obliquely on a surface of the inspection target10. The mover121may vary the position of the light source120on the basis of a control performed by the processor160which will be described later, to thereby vary an incident angle of the light La emitted from the light source120with respect to the inspection target10. The mover131may vary the position of the light detector130on the basis of a control performed by the processor160which will be described later, to thereby cause the light detector130or a light reception surface of the image sensor to stay on the optical path of the reflected light Lb.

The pattern inspection apparatus100may further include, for example, the inspection unit150, the processor160, and a display170, as illustrated inFIG.2.

The inspection unit150may perform pattern inspection of the inspection target10on the basis of the detection result D1obtained from the light detector130and the detection result D2obtained from the light detector140. For example, the inspection unit150may perform the pattern inspection of the inspection target10with use of the image data Ib and the image data Ic. The inspection unit150may perform the pattern inspection on the basis of a plurality of detection results D1and a plurality of detection results D2obtained in a process in which the incident angle of the light La with respect to the inspection target10is varied by the mover121. Such detection results D1and detection results D2may each be referred to as test data. For example, the inspection unit150may perform the pattern inspection on the basis of a plurality of pieces of image data Ib and a plurality of pieces of image data Ic obtained in the process in which the incident angle of the light La with respect to the inspection target10is varied by the mover121. Such pieces of image data Ib and image data Ic may each be referred to as the test data. Thus, the pieces of test data may include the detection results D1that differ from each other in the incident angle and the detection results D2that differ from each other in the incident angle, or the pieces of image data Ib that differ from each other in the incident angle and the pieces of image data Ic that differ from each other in the incident angle.

Note that, in one example, in a case where the inspection unit150acquires the detection result D1from the light detector130and acquires the detection result D2from the light detector140, the inspection unit150may generate the image data Ib on the basis of the detection result D1acquired from the light detector130and may generate the image data Ic on the basis of the detection result D2acquired from the light detector140.

The inspection unit150may have, as pieces of master data, a plurality of detection results D1and D2or a plurality of pieces of image data Ib and Ic obtained from an inspection target10having no defect. The pieces of master data may include the detection results D1that differ from each other in the incident angle and the detection results D2that differ from each other in the incident angle, or the pieces of image data Ib that differ from each other in the incident angle and the pieces of image data Ic that differ from each other in the incident angle. The inspection unit150may compare the master data and the test data that are the same as each other in the incident angle, to thereby determine presence or absence of an unusual point regarding the inspection target10from which the test data has been acquired. The unusual point may refer to a factor that suggests presence of a defect. Examples of a comparison method may include a method of obtaining a difference between the master data and the test data. In a case where the inspection unit150determines the absence of the unusual point as a result of the comparison, the inspection unit150may generate information indicating the absence of the unusual point and supply the generated information to the processor160. In contrast, in a case where the inspection unit150determines the presence of the unusual point, the inspection unit150may generate information indicating the presence of the unusual point and supply the generated information to the processor160.

In one example, the inspection unit150may compare the detection result D1and the detection result D2that are the same as each other in the incident angle or may compare the image data Ib and the image data Ic that are the same as each other in the incident angle to thereby determine the presence or absence of the unusual point regarding the inspection target10. Examples of a comparison method may include a method of obtaining a difference between the detection result D1and the detection result D2and a method of obtaining a difference between the image data Ib and the image data Ic. In this case, the master data may be unnecessary in determining the presence or absence of the unusual point regarding the inspection target10.

In one example, the inspection unit150may have a learning model that has learned with use of teaching data including, for example, the detection result D1and the detection result D2or the image data Ib and the image data Ic obtained from the inspection target10having no defect; and detection results D1and detection results D2or pieces of image data Ib and pieces of image data Ic obtained from a plurality of inspection targets10that differ from each other in a factor such as a location of a defect or a kind of a defect. In this case, the inspection unit150may input the test data in the learning model, and cause the learning model to determine the presence or absence of the unusual point regarding the inspection target10from which the inputted test data has been acquired. The inspection unit150may supply a determination result obtained by the learning model to the processor160.

In one example, the inspection unit150may have a learning model that has learned with use of teaching data including, for example, a difference between the detection result D1and the detection result D2obtained from the inspection target10having no defect; and a difference between detection results D1and detection results D2obtained from a plurality of inspection targets10that differ from each other in a factor such as a location of a defect or a kind of a defect. In this case, the inspection unit150may input in the learning model a difference between a detection result D1and a detection result D2obtained from the inspection target10for testing, and cause the learning model to determine the presence or absence of the unusual point regarding the inspection target10for testing. The inspection unit150may supply a determination result obtained by the learning model to the processor160.

In one example, the inspection unit150may have a learning model that has learned with use of teaching data including, for example, a difference between the image data Ib and the image data Ic obtained from the inspection target10having no defect; and a difference between pieces of image data Ib and pieces of image data Ic obtained from a plurality of inspection targets10that differ from each other in a factor such as a location of a defect or a kind of a defect. In this case, the inspection unit150may input in the learning model a difference between image data Ib and image data Ic obtained from the inspection target10for testing, and cause the learning model to determine the presence or absence of the unusual point regarding the inspection target10for testing. The inspection unit150may supply a determination result obtained by the learning model to the processor160.

The processor160may control the light source120, the light detectors130and140, and the movers121,131, and141. The processor160may control turning on and off of light emission of the light source120. The processor160may control light reception of the light detectors130and140. The processor160may control a position to which the mover121moves the light source120, a position to which the mover131moves the light detector130, and a position to which the mover141moves the light detector140. The processor160may supply the display170with image data including the determination result obtained by the inspection unit150. The display170may display the image data supplied from the processor160.

Next, referring toFIG.4, a description is given of an example of inspection of the inspection target10to be performed by the pattern inspection apparatus100.

First, the processor160may set the incident angle of the light La (step S101). To set the incident angle of the light La to a predetermined value within a sweep range, i.e., to a start point, the processor160may supply a signal regarding position information to the mover121. On the basis of the signal supplied from the processor160, the mover121may so move the light source120that the incident angle of the light La becomes the predetermined value, i.e., the start point. Thereafter, the processor160may supply a signal to start light emission to the light source120. On the basis of the signal supplied from the processor160, the light source120may emit the light La (step S102).

Thereafter, the processor160may supply a signal to start light detection to each of the light detectors130and140. The light detector130may detect the reflected light Lb on the basis of the signal supplied from the processor160(step S103). The light detector130may generate the image data Ib on the basis of the detection result D1and supply the generated image data Ib to the inspection unit150(step S104). The light detector140may detect the transmitted light Lc on the basis of the signal supplied from the processor160(step S103). The light detector140may generate the image data Ic on the basis of the detection result D2and supply the generated image data Ic to the inspection unit150(step S104).

The processor160may determine whether the currently set incident angle is the last incident angle within the sweep range, i.e., an end point (step S105). If the currently set incident angle is not the last incident angle within the sweep range, i.e., is not the end point (step S105: N), the processor160may vary the incident angle of the light La within the sweep range (step S106). For example, the processor160may supply a signal regarding the position information to the mover121to set the incident angle of the light La to a value that is shifted from the currently set incident angle toward the end point by a predetermined amount. Thereafter, the processor160may execute processes in the respective steps S103to S105.

In contrast, if the currently set incident angle corresponds to the last incident angle within the sweep range, i.e., to the end point (step S105: Y), the processor160may end the varying of the incident angle of the light La and supply the inspection unit150with a signal to start incident-angle-based comparison between the pieces of image data Ib and Ic each of which is the test data and pieces of image data Ir1and Ir2each of which is the master data. The inspection unit150may perform the incident-angle-based comparison described above (step S107). The image data Ir1may correspond to the image data Ib obtained from the inspection target10having no defect. The image data Ir2may correspond to the image data Ic obtained from the inspection target10having no defect.

For example, the inspection unit150may obtain a difference between the image data Ib and the image data Ir1, which is hereinafter referred to as a “difference α”, and may also obtain a difference between the image data Ic and the image data Ir2, which is hereinafter referred to as a “difference β”. For example, the inspection unit150may determine whether the differences α and β involve any unusual point (step S108). If the difference α, the difference β, or both are determined as involving unusual points as a result (step S108: Y), the inspection unit150may determine that the inspection target10has a defect (step S110). In contrast, if neither the difference α nor the difference β is determined as involving unusual points as a result (step S108: N), the inspection unit150may determine that the inspection target10has no defect (step S109).

The processor160may generate image data including the determination result obtained by the inspection unit150, and supply the generated image data to the display170. The display170may display the image data supplied from the processor160. In such a manner, the pattern inspection apparatus100may perform the inspection of the inspection target10.

Next, a description is given of effects of the pattern inspection apparatus100according to the first example embodiment.

Recently, in terms of advancing high integration of integrated circuits, it has reached a physical limit to miniaturize circuits. This has led to stacking of circuits, i.e., three-dimensionalization of circuits. For existing planar circuits, it is possible to perform non-destructive inspection to check defects of all the products to be actually used. For example, Japanese Unexamined Patent Application Publication No. 2013-068551 discloses to apply nanometer-order light to a circuit pattern and to detect a defect of the circuit pattern on the basis of a diffraction image obtained by the nanometer-order light application. When it comes to three-dimensional circuits, however, difficulty in detecting defects of internal circuit patterns has been an issue.

According to the first example embodiment of the technology, out of the light La emitted toward the inspection target10and having the wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 the transmitted light Lc of the inspection target10or the reflected light Lb of the inspection target10is detected. This allows for performing pattern inspection on the basis of a detection result obtained by the detection. Accordingly, it is possible to also detect a defect of an internal circuit pattern in a three-dimensional circuit.

In addition, according to the first example embodiment, the pattern inspection may be performed on the basis of the plurality of detection results D1and the plurality of detection results D2or the plurality of pieces of image data Ib and the plurality of pieces of image data Ic obtained by the detectors130and140in the process in which the incident angle is varied. This makes it possible to also detect a defect of the internal circuit pattern in the three-dimensional circuit.

Note that, in the first example embodiment, the inspection unit150may perform the pattern inspection on the basis of the detection result D1or the detection result D2in one example. In addition, in the first example embodiment, the inspection unit150may perform the pattern inspection on the basis of the image data Ib or the image data Ic in one example. In such cases also, it is possible to also detect a defect of the internal circuit pattern in the three-dimensional circuit.

3. Second Example Embodiment

Next, a description is given of a pattern inspection apparatus200according to a second example embodiment of the technology.FIG.5illustrates an example of a schematic configuration of the pattern inspection apparatus200. The pattern inspection apparatus200may perform non-destructive inspection of a defect in the inspection target10. For example, as illustrated inFIG.5, the pattern inspection apparatus200may correspond to the above-described pattern inspection apparatus100in which the movers121,131, and141are omitted and a light source180is provided in place of the light source120. In the following, configurations common to the first example embodiment are denoted with the same numerals and descriptions of the configurations common to the first example embodiment are omitted where appropriate.

The light source180may include a laser configured to emit light Ld and a control circuit that controls light emission of the laser. The laser may be so disposed that the light Ld emitted from the laser is incident obliquely on the surface of the inspection target. The control circuit may control the light emission of the laser on the basis of a control performed by the processor160. The laser may be configured to emit, as the light Ld, collimated light having a wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 μm, i.e., a wavelength band of the mid-infrared region. The laser may be, for example, a GaSb-based semiconductor laser configured to emit the light Ld having any wavelength within a range that is greater than or equal to 1.9 μm and less than or equal to 2.5 μm. The laser is, however, not limited to a semiconductor laser, and may be a solid-state laser. In one example, the laser may be a Cr:ZnSe laser configured to emit the light Ld having any wavelength within a range that is greater than or equal to 2.2 μm and less than or equal to 2.9 μm. The laser is not limited to the Cr:ZnSe laser. In place of the above-described laser, the light source180may include, for example, a light emitting device configured to emit the light Ld having any wavelength within a range that is greater than or equal to 2.2 μm and less than or equal to 2.9 μm. For example, as illustrated inFIG.3, the above-described mid-infrared region is included in the light transmission region of the Si substrate. Accordingly, the light Ld is able to be transmitted through the Si substrate and the inspection target10including the Si substrate.

When the light Ld is incident on the inspection target10, a portion of the incident light Ld may be reflected by the inspection target10to become reflected light Lb, which may be incident on the light detector130; another portion of the incident light Ld may be transmitted through the inspection target10to become transmitted light Lc, which may be incident on the light detector140. The inspection target10may be optically regarded as a volume Bragg grating. In this case, the reflected light Lb may be Bragg reflected light that is light diffracted inside the inspection target10. The reflected light Lb may have high diffraction intensity in a particular direction. Similarly, the transmitted light Lc may also have high diffraction intensity in a particular direction.

The inspection unit150may perform pattern inspection of the inspection target10on the basis of the detection result D1obtained from the light detector130and the detection result D2obtained from the light detector140. For example, the inspection unit150may perform the pattern inspection of the inspection target10with use of the image data Ib and the image data Ic. The inspection unit150may perform the pattern inspection on the basis of a plurality of detection results D1and a plurality of detection results D2obtained in a process in which the wavelength of the light Ld is varied. Such detection results D1and such detection results D2may each be referred to as test data. For example, the inspection unit150may perform the pattern inspection on the basis of a plurality of pieces of image data Ib and a plurality of pieces of image data Ic obtained in the process in which the wavelength of the light Ld is varied. Such pieces of image data Ib and such pieces of image data Ic may each be referred to as test data. Thus, the pieces of test data may include the detection results D1that differ from each other in the wavelength of the light Ld and the detection results D2that differ from each other in the wavelength of the light Ld, or the pieces of image data Ib that differ from each other in the wavelength of the light Ld and the pieces of image data Ic that differ from each other in the wavelength of the light Ld.

The inspection unit150may have, as pieces of master data, a plurality of detection results D1and D2or a plurality of pieces of image data Ib and Ic obtained from an inspection target10having no defect. The pieces of master data may include the detection results D1that differ from each other in the wavelength of the light Ld and the detection results D2that differ from each other in the wavelength of the light Ld, or the pieces of image data Ib that differ from each other in the wavelength of the light Ld and the pieces of image data Ic that differ from each other in the wavelength of the light Ld. The inspection unit150may compare the master data and the test data that are the same as each other in the wavelength of the light Ld, to thereby determine presence or absence of an unusual point regarding the inspection target10from which the test data has been acquired. The unusual point may refer to a factor that suggests presence of a defect. Examples of a comparison method may include a method of obtaining a difference between the master data and the test data. In a case where the inspection unit150determines the absence of the unusual point as a result of the comparison, the inspection unit150may generate information indicating the absence of the unusual point and supply the generated information to the processor160. In contrast, in a case where the inspection unit150determines the presence of the unusual point, the inspection unit150may generate information indicating the presence of the unusual point and supply the generated information to the processor160.

In one example, the inspection unit150may compare the detection result D1and the detection result D2that are the same as each other in the wavelength of the light Ld or may compare the image data Ib and the image data Ic that are the same as each other in the wavelength of the light Ld to thereby determine the presence or absence of the unusual point regarding the inspection target10. Examples of a comparison method may include a method of obtaining a difference between the detection result D1and the detection result D2and a method of obtaining a difference between the image data Ib and the image data Ic. In this case, the master data may be unnecessary in determining the presence or absence of the unusual point regarding the inspection target10.

The processor160may control the light source180and the light detectors130and140. The processor160may control, for example, turning on and off of light emission of the light source180and the wavelength of the light emitted from the light source180. The processor160may control light reception of the light detectors130and140. The processor160may supply the display170with image data including the determination result obtained by the inspection unit150. The display170may display the image data supplied from the processor160.

Next, referring toFIG.6, a description is given of an example of inspection of the inspection target10to be performed by the pattern inspection apparatus200.

First, the processor160may set the wavelength of the light Ld (step S201). To set the wavelength of the light Ld to a predetermined value within a sweep range, i.e., to a start point, the processor160may supply a signal regarding a wavelength to the light source180. On the basis of the signal supplied from the processor160, the light source180may emit the light Ld having the wavelength of the predetermined value, i.e., the start point (step S202).

Thereafter, the processor160may supply a signal to start light detection to each of the light detectors130and140. The light detector130may detect the reflected light Lb on the basis of the signal supplied from the processor160(step S203). The light detector130may generate the image data Ib on the basis of the detection result D1and supply the generated image data Ib to the inspection unit150(step S204). The light detector140may detect the transmitted light Lc on the basis of the signal supplied from the processor160(step S203). The light detector140may generate the image data Ic on the basis of the detection result D2and supply the generated image data Ic to the inspection unit150(step S204).

The processor160may determine whether the currently set wavelength of the light Ld is the last wavelength within the sweep range, i.e., an end point (step S205). If the currently set wavelength of the light Ld is not the last wavelength within the sweep range, i.e., is not the end point (step S205: N), the processor160may vary the wavelength of the light Ld within the sweep range (step S206). For example, the processor160may supply a signal regarding the wavelength to the light source180to set the wavelength of the light Ld to a value that is shifted from the currently set wavelength of the light Ld toward the end point by a predetermined amount. Thereafter, the processor160may execute processes in the respective steps S203to S205.

In contrast, if the currently set wavelength of the light Ld corresponds to the last wavelength within the sweep range, i.e., to the end point (step S205: Y), the processor160may end the varying of the wavelength of the light Ld and supply the inspection unit150with a signal to start wavelength-based comparison between the pieces of image data Ib and Ic each of which is the test data and pieces of image data Ir3and Ir4each of which is the master data. The inspection unit150may perform the wavelength-based comparison described above (step S207). The image data Ir3may correspond to the image data Ib obtained from the inspection target10having no defect. The image data Ir4may correspond to the image data Ic obtained from the inspection target10having no defect.

For example, the inspection unit150may obtain a difference between the image data Ib and the image data Ir3, which is hereinafter referred to as a “difference α”, and may also obtain a difference between the image data Ic and the image data Ir4, which is hereinafter referred to as a “difference β”. For example, the inspection unit150may determine whether the differences α and β involve any unusual point (step S208). If the difference α, the difference β, or both are determined as involving unusual points as a result (step S208: Y), the inspection unit150may determine that the inspection target10has a defect (step S210). In contrast, if neither the difference α nor the difference β is determined as involving unusual points as a result (step S208: N), the inspection unit150may determine that the inspection target10has no defect (step S209).

The processor160may generate image data including the determination result obtained by the inspection unit150, and supply the generated image data to the display170. The display170may display the image data supplied from the processor160. In such a manner, the pattern inspection apparatus200may perform the inspection of the inspection target10.

Next, a description is given of effects of the pattern inspection apparatus200according to the second example embodiment.

According to the second example embodiment of the technology, out of the light Ld emitted toward the inspection target10and having the wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 the transmitted light Lc of the inspection target10or the reflected light Lb of the inspection target10is detected. This allows for performing pattern inspection on the basis of a detection result obtained by the detection. Accordingly, it is possible to also detect a defect of an internal circuit pattern in a three-dimensional circuit.

In addition, according to the second example embodiment, the pattern inspection may be performed on the basis of the plurality of detection results D1and the plurality of detection results D2or the plurality of pieces of image data Ib and the plurality of pieces of image data Ic obtained by the detectors130and140in the process in which the wavelength of the light Ld is varied. This makes it possible to also detect a defect of the internal circuit pattern in the three-dimensional circuit.

In each of a pattern inspection apparatus and a pattern inspection method according to one example embodiment of the technology, out of light emitted toward an inspection target and having a wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 transmitted light of the inspection target or reflected light of the inspection target is detected. Accordingly, it is possible to perform pattern inspection on the basis of a detection result obtained by the detection.

According to each of the pattern inspection apparatus and the pattern inspection method according to one example embodiment of the technology, out of light emitted toward an inspection target and having a wavelength band that is greater than or equal to 1.2 μm and less than or equal to 5.0 transmitted light of the inspection target or reflected light of the inspection target is detected. This allows for performing pattern inspection on the basis of a detection result obtained by the detection. Accordingly, it is possible to also detect a defect of an internal circuit pattern in a three-dimensional circuit.

Furthermore, the technology encompasses any possible combination of some or all of the various embodiments and the modifications described herein and incorporated herein. It is possible to achieve at least the following configurations from the above-described example embodiments of the technology.

(1)A pattern inspection apparatus including:a light source configured to emit light toward an inspection target including stacked silicon substrates, the light having a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers;a detector configured to detect transmitted light of the inspection target or reflected light of the inspection target out of the light emitted from the light source, the transmitted light being light transmitted through the inspection target, the reflected light being light reflected by the inspection target; andan inspection unit configured to perform pattern inspection on the basis of a detection result obtained by the detector.
(2)The pattern inspection apparatus according to (1), further includinga mover configured to vary a position of the light source to thereby vary an incident angle, with respect to the inspection target, of the light emitted from the light source, in whichthe inspection unit is configured to perform the pattern inspection on the basis of a plurality of the detection results obtained by the detector in a process in which the incident angle is varied by the mover.
(3)The pattern inspection apparatus according to (1), in whichthe light source is configured to vary a wavelength of the light to emit within a range of the wavelength band, andthe inspection unit is configured to perform the pattern inspection on the basis of a plurality of the detection results obtained by the detector in a process in which the wavelength of the light to emit is varied by the light source.
(4)The pattern inspection apparatus according to any one of (1) to (3), in whichthe reflected light includes reflected Bragg diffraction light that is a diffraction image generated by light reflected inside the inspection target, andthe transmitted light includes transmitted Bragg diffraction light that is a volume diffraction image generated by the transmitted light of the inspection target.
(5)A pattern inspection method including:emitting light toward an inspection target including stacked silicon substrates, the light having a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers;detecting transmitted light of the inspection target or reflected light of the inspection target out of the light emitted toward the inspection target, the transmitted light being light transmitted through the inspection target, the reflected light being light reflected by the inspection target; andperforming pattern inspection on the basis of a detection result obtained by the detecting.
(6)The pattern inspection method according to (5), further including:varying an incident angle, with respect to the inspection target, of the light emitted toward the inspection target; andperforming the pattern inspection on the basis of a plurality of the detection results obtained in a process in which the incident angle is varied.
(7)The pattern inspection method according to (5), further includingvarying a wavelength of the light to emit within a range of the wavelength band; andperforming the pattern inspection on the basis of a plurality of the detection results obtained in a process in which the wavelength of the light to emit is varied.
(8)The pattern inspection method according to any one of (5) to (7), in whichthe reflected light includes reflected Bragg diffraction light that is a diffraction image generated by light reflected inside the inspection target, andthe transmitted light includes transmitted Bragg diffraction light that is a volume diffraction image generated by the transmitted light of the inspection target.

Although some embodiments of the technology have been described in the foregoing by way of example with reference to the accompanying drawings, the technology is by no means limited to the embodiments described above. It should be appreciated that modifications and alterations may be made by persons skilled in the art without departing from the scope as defined by the appended claims. The technology is intended to include such modifications and alterations in so far as they fall within the scope of the appended claims or the equivalents thereof.