Defect Detection Device and Defect Detection Method

Abstract

The present invention provides a defect detection device and a defect detection method, which can detect defects on the bonding surface of a semiconductor die in a short time with a simple structure. The defect detection device for detecting defects of a semiconductor device includes: an ultrasonic horn for ultrasonically exciting the semiconductor device; a laser light source for irradiating the semiconductor device with parallel laser light; a camera having an imaging element that captures an image of the semiconductor device irradiated with the parallel laser light; and a detection unit for detecting defects of the semiconductor device based on the image captured by the camera. The detection unit performs defect detection of the semiconductor device based on the deviation between the image of the semiconductor device at rest and the image during ultrasonic vibration obtained by the camera.

Description

Technical Field

[0001] The present invention relates to a structure of a defect detection device for detecting defects in an object to be inspected using ultrasonic waves, and a defect detection method for detecting defects using ultrasonic waves. Background Art

[0002] In the manufacture of semiconductor devices, die bonding is performed in which a semiconductor die is bonded to a substrate or a semiconductor die is bonded on top of a semiconductor die. In die bonding, sometimes bonding defects occur at the bonding surface between the substrate and the semiconductor die, or at the bonding surface between the semiconductor die and the semiconductor die bonded above. Therefore, the bonding state of the bonding surface between the substrate and the semiconductor die or between the semiconductor dies is inspected.

[0003] Since such a bonding surface cannot be directly observed from the outside, for example, a scanning acoustic microscope or the like (for example, refer to Patent Document 1) is used for inspection.

[0004] It is also known that when ultrasonic vibrations are incident on an object to be inspected having a defect inside, the temperature of the part having a defect such as a crack is higher than that of other parts. Based on the above principle, the following non-destructive inspection device can be used: ultrasonic vibrations generated by an ultrasonic oscillator are incident on the object to be inspected, and an infrared thermography is used to obtain an image of the temperature distribution on the surface of the object to be inspected, and the part with a high temperature is detected as a defect (for example, refer to Patent Document 2).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 61-254834

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2016-191552 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, the scanning acoustic microscope described in Patent Document 1 must scan the object to be inspected, so there are problems such as the inspection device becoming complicated and the inspection taking time.

[0011] In addition, the inspection device of the prior art described in Patent Document 2 performs defect detection based on the difference in the temperature rise of the object to be inspected caused by ultrasonic vibration. Therefore, there are the following problems: defects cannot be detected during the period from when ultrasonic vibration is applied to the object to be inspected until the temperature of the object to be inspected rises to the level required for defect detection, and defect detection takes time, etc.

[0012] Therefore, an object of the present invention is to provide a defect detection device that can perform defect detection on the bonding surface of a semiconductor die in a short time using a simple structure.

[0013] Technical means for solving the problem

[0014] The defect detection device of the present invention detects defects in an object to be inspected, and is characterized by including: an ultrasonic vibrator that ultrasonically vibrates the object to be inspected; a coherent light source that irradiates the object to be inspected with coherent light; a camera having an imaging element that captures an image of the object to be inspected irradiated with the coherent light; and a detection unit that performs defect detection on the object to be inspected based on the image captured by the camera. The detection unit performs defect detection on the object to be inspected based on the deviation between the image of the object to be inspected at rest and the image of the object to be inspected during ultrasonic vibration obtained by the camera.

[0015] In this way, by irradiating the object to be inspected with coherent light and performing ultrasonic vibration, and performing defect detection based on the deviation between the image at rest and the image during ultrasonic vibration, it is not necessary to scan the camera, and defect detection can be performed in a short time using a simple structure.

[0016] In the defect detection device of the present invention, the exposure time when the camera takes a picture may be longer than the period of ultrasonic vibration of the object to be inspected, and an image including an interference pattern generated by the interference of the coherent light reflected from the surface of the object to be inspected is obtained. The detection unit performs defect detection on the object to be inspected based on the deviation between the image of the object to be inspected including the interference pattern at rest and the image of the object to be inspected including the interference pattern during ultrasonic vibration obtained by the camera.

[0017] If coherent light is irradiated onto the surface of an object to be inspected, the coherent light interferes due to reflection, and an interference pattern appears on the surface of the imaging element of the camera. The imaging element of the camera acquires the interference pattern as an image. Since the exposure time of the camera during shooting is longer than the vibration period of the object to be inspected, if the object to be inspected vibrates, the camera acquires an image of a flickering interference pattern. If the image of the interference pattern flickers, the intensity of the brightness of the pixels changes compared to the case when it is stationary. If there are defects inside the object to be inspected, such as defects in the bonding surface of a semiconductor die, the defective part vibrates due to ultrasonic excitation. Therefore, the image of the interference pattern flickers in the defective part, and the intensity of the brightness of the pixels changes compared to the case when it is stationary. Thus, based on the deviation between the image including the interference pattern at rest and the image including the interference pattern during ultrasonic vibration, defective detection of the object to be inspected can be performed.

[0018] In the defective detection device of the present invention, the detection unit may also determine vibration-generated pixels based on the deviation, and set a region where the determined vibration-generated pixels are concentrated to a value equal to or greater than a predetermined value as a defective region to detect defects.

[0019] If the vibration caused by a bonding defect causes the image of the interference pattern to flicker, the intensity of the brightness of the pixels changes compared to the case when it is stationary. Therefore, pixels whose intensity of brightness during vibration changes compared to the intensity of brightness at rest can be determined as vibration-generated pixels, and a region where the determined vibration-generated pixels are concentrated to a value equal to or greater than a predetermined value is set as a defective region to detect defects.

[0020] In the defective detection device of the present invention, when a predetermined number of other vibration-generated pixels exist within a predetermined range around the determined vibration-generated pixels, the detection unit maintains the determination of the vibration-generated pixels of the pixel, and when the predetermined number of vibration-generated pixels does not exist within the predetermined range, the detection unit cancels the determination of the vibration-generated pixels of the pixel.

[0021] Thus, it is possible to suppress the determination of pixels that do not actually vibrate as vibration-generated pixels due to noise, and perform vibration detection with high accuracy.

[0022] The defective detection device of the present invention may include: a display that displays an image of the object to be inspected, and the detection unit displays a visualized image on the display, where the visualized image is formed by making the image of the object to be inspected include a display corresponding to the determined vibration-generated pixels.

[0023] Thus, it is possible to visualize and display the part that vibrates due to a defect existing inside the object to be inspected.

[0024] In the defective detection device of the present invention, the coherent light may also be laser light, and the coherent light source irradiates parallel laser light of a single wavelength onto the object to be inspected.

[0025] By irradiating parallel laser light of a single wavelength, the interference pattern of the laser light appears more clearly, and the speckle pattern captured by the camera becomes clearer. Thereby, vibration can be detected with higher precision.

[0026] The defect detection device of the present invention may also include: a drive unit that supplies high-frequency power to the ultrasonic vibrator; and a control unit that adjusts the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator. When the detection unit performs defect detection on the object to be inspected, the control unit changes the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator.

[0027] The frequency at which the defective part easily vibrates varies depending on the size, hardness of the object to be inspected, or the state of the defective part, etc. Therefore, by changing the frequency of ultrasonic vibration and subjecting the object to be inspected to ultrasonic vibration at various frequencies, the accuracy of defect detection can be improved.

[0028] The defect detection device of the present invention may also include: a current sensor that detects the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator. When the control unit changes the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, it adjusts the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator so that the current detected by the current sensor falls within a predetermined range.

[0029] The ultrasonic vibrator has its own resonance frequency. Therefore, if high-frequency power of the resonance frequency is input to the ultrasonic vibrator during ultrasonic vibration, the impedance of the ultrasonic vibrator decreases due to resonance, and the amplitude of the ultrasonic vibrator becomes larger, causing the entire object to be inspected to vibrate significantly. Thereby, sometimes the amplitude of the object part is obscured by the amplitude of the non-object part and cannot be detected. The amplitude of the ultrasonic vibrator is proportional to the current of the high-frequency power input to the ultrasonic vibrator. Therefore, by using the current sensor to detect the current of the high-frequency power input to the ultrasonic vibrator and adjusting the voltage of the high-frequency power so that the detected current falls within a predetermined range, the current of the high-frequency power can be set within a predetermined range and the amplitude of the ultrasonic vibrator can be set within a predetermined range. Thereby, it is possible to suppress the situation where the entire object to be inspected vibrates significantly during ultrasonic vibration of the object to be inspected, and the amplitude of the object part is obscured by the amplitude of the non-object part and cannot be detected, and defects of the object part of the object to be inspected can be detected with high precision.

[0030] In the defective detection device of the present invention, the control unit may also include: a mapping that prescribes in advance the change of the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator with respect to the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator so that the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator falls within a predetermined range. When changing the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator is adjusted based on the mapping.

[0031] Thereby, it is not necessary to adjust the voltage of the high-frequency power based on the feedback of the current detected by the current sensor, and a simple structure can be used to suppress the following situation: when ultrasonically exciting the inspection object, the entire inspection object vibrates greatly, and the amplitude of the target part is obscured by the amplitude of the non-target part and cannot be detected, and the defect of the target part of the inspection object can be detected with high precision.

[0032] In the defective detection device of the present invention, the ultrasonic vibrator may also be an ultrasonic horn arranged around the inspection object or an ultrasonic vibrator connected to the inspection object to cause the inspection object to perform ultrasonic vibration.

[0033] Thereby, an appropriate ultrasonic vibrator can be selected based on the type, size, etc. of the inspection object to constitute a defective detection device.

[0034] In the defective detection device of the present invention, the ultrasonic vibrator may also be composed of a plurality of directional ultrasonic horns arranged around the inspection object, and the plurality of ultrasonic horns are installed in a casing in such a way that the ultrasonic waves generated from each ultrasonic horn are concentrated on the inspection object.

[0035] In this way, the ultrasonic waves from the plurality of ultrasonic horns are concentrated on the inspection object, and the defective detection is performed by indirectly ultrasonically exciting the inspection object. Therefore, compared with the case where ultrasonic vibration is directly incident on the inspection object, the defective detection can be performed with a simple structure. In addition, since the inspection object is indirectly ultrasonically excited, the defective detection of the inspection object can be performed in a non-contact manner.

[0036] The defective detection device of the present invention may also include: a plurality of drive units that supply high-frequency power to the plurality of ultrasonic horns respectively; and a control unit that adjusts the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn. When the detection unit performs defective detection of the inspection object, the control unit changes the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn.

[0037] When ultrasonically exciting an object to be inspected by a plurality of ultrasonic horns, the ultrasonic excitation of the object to be inspected is also performed at various frequencies by changing the frequency of the ultrasonic excitation, thereby improving the accuracy of defect detection.

[0038] The defect detection device of the present invention may also include: current sensors that respectively detect the currents of the high-frequency power supplied from each drive unit to each ultrasonic horn, and a control unit that, when changing the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn, adjusts the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn so that the currents detected by the respective current sensors fall within a predetermined range.

[0039] Thereby, when ultrasonically exciting an object to be inspected by a plurality of ultrasonic horns, defects in the target part of the object to be inspected can also be detected with high precision.

[0040] In the defect detection device of the present invention, the control unit may also include: a map that prescribes in advance the change of the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn with respect to the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn so that the currents of the high-frequency power supplied from each drive unit to each ultrasonic horn respectively fall within a predetermined range, and when changing the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn, adjusts the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn based on the map.

[0041] Thereby, when ultrasonically exciting an object to be inspected by a plurality of ultrasonic horns, defects in the target part of the object to be inspected can also be detected with high precision using a simple structure.

[0042] In the defect detection device of the present invention, the control unit may also adjust the phases of the respective ultrasonic waves generated by each ultrasonic horn through each drive unit.

[0043] Thereby, when ultrasonically exciting an object to be inspected by a plurality of ultrasonic horns, the ultrasonic waves can be superimposed to increase the ultrasonic vibration in the detection area, and the object to be inspected can be effectively ultrasonically excited.

[0044] The defective detection method of the present invention detects defects of an object to be inspected, and is characterized by including: a static image acquisition step of irradiating the object to be inspected with coherent light and using a camera to photograph the object to be inspected to acquire a static image of the object to be inspected; an ultrasonic vibration image acquisition step of irradiating the object to be inspected with coherent light while exciting the object to be inspected ultrasonically by an ultrasonic vibrator and using a camera to photograph the object to be inspected to acquire an image of the object to be inspected during ultrasonic vibration; and a defective detection step of performing defective detection of the object to be inspected based on the deviation between the static image and the ultrasonic vibration image of the object to be inspected acquired by the camera.

[0045] In the defective detection method of the present invention, in the static image acquisition step, the camera may also be used to acquire an image including an interference pattern at rest, which is generated by the interference of the coherent light reflected from the surface of the object to be inspected. In the ultrasonic vibration image acquisition step, the exposure time of the camera is made longer than the period of the ultrasonic vibration of the object to be inspected, and the camera is used to acquire an image including an interference pattern during ultrasonic vibration, which is generated by the interference of the coherent light reflected from the surface of the object to be inspected. The defective detection step performs defective detection of the object to be inspected based on the deviation between the image of the object to be inspected including the interference pattern at rest and the image including the interference pattern during ultrasonic vibration acquired by the camera.

[0046] In the defective detection method of the present invention, the defective detection step may also determine vibration-generated pixels based on the deviation, set an area where the determined vibration-generated pixels are concentrated to a value equal to or greater than a predetermined value as a defective area, and detect defects.

[0047] In the defective detection method of the present invention, in the defective detection step, when a predetermined number of other vibration-generated pixels exist within a predetermined range around the determined vibration-generated pixels, the determination of the vibration-generated pixels of the pixels is maintained, and when the predetermined number of vibration-generated pixels does not exist within the predetermined range, the determination of the vibration-generated pixels of the pixels is cancelled.

[0048] In the defective detection method of the present invention, it may also include: a display step of displaying a visualized image on a display, where the visualized image is formed by making the image of the object to be inspected include a display corresponding to the determined vibration-generated pixels.

[0049] The vibration detection device of the present invention detects the vibration of an object to be inspected, and is characterized by including: an ultrasonic exciter that ultrasonically excites the object to be inspected; a coherent light source that irradiates the object to be inspected with coherent light; a camera having an imaging element that captures an image of the object to be inspected irradiated with the coherent light; and a detection unit that processes the image captured by the camera to determine the vibration generation site. When the camera takes a picture, the exposure time is longer than the period of the ultrasonic vibration of the object to be inspected, and an image including an interference pattern is obtained. The interference pattern is generated by the interference of the coherent light reflected from the surface of the object to be inspected. The detection unit determines the vibration generation site of the object to be inspected based on the deviation between the image of the object to be inspected obtained by the camera, which includes the interference pattern at rest, and the image including the interference pattern during ultrasonic vibration.

[0050] In the vibration detection device of the present invention, it may also include: a display that displays an image of the object to be inspected. The detection unit determines vibration generation pixels indicating the vibration generation site based on the deviation, and displays a visualization image on the display. The visualization image is formed by making the image of the object to be inspected include a display corresponding to the determined vibration generation pixels.

[0051] Effects of the Invention

[0052] The present invention can provide a defect detection device that can perform defect detection on the bonding surface of a semiconductor die in a short time using a simple structure. Description of the Drawings

[0053] Figure 1 An elevation view showing the structure of the defect detection device according to the embodiment.

[0054] Figure 2 A schematic diagram showing the state in which parallel laser light reflected from the surface of the semiconductor die enters the imaging element of the camera when the semiconductor device is at rest without ultrasonic excitation.

[0055] Figure 3 For showing in Figure 2 A schematic diagram of the image captured by the camera in this state.

[0056] Figure 4 A schematic diagram showing the vibration of the bonding defect part when the semiconductor device is ultrasonically excited.

[0057] Figure 5 A schematic diagram showing the state in which the vibration of the parallel laser light reflected from the surface of the semiconductor die and the state in which the reflected laser light enters the imaging element of the camera when the bonding defect part vibrates due to ultrasonic excitation of the semiconductor device.

[0058] Figure 6 For showing in Figure 5Schematic diagram of an image captured by a camera in a certain state.

[0059] Figure 7 Schematic diagram showing pixels of the imaging element of a camera.

[0060] Figure 8 Schematic diagram showing a visualized image displayed on a display.

[0061] Figure 9 To represent Figure 1 Flowchart showing the operation of the defect detection device shown.

[0062] Figure 10 To represent Figure 1 Flowchart showing the operation of the defect detection device for determining vibration - generating pixels shown.

[0063] Figure 11 Elevation view showing the structure of a defect detection device of another embodiment.

[0064] Figure 12 System diagram showing the structure of a defect detection device of another embodiment in which a semiconductor device is ultrasonically excited using an ultrasonic oscillator.

[0065] Figure 13 Graph showing the change in impedance of an ultrasonic oscillator and the change in current of high - frequency power with respect to the frequency of high - frequency power in the case where the voltage of the high - frequency power supplied to the ultrasonic oscillator of the prior art is set constant.

[0066] Figure 14 To represent in Figure 12 Graph showing the change in voltage and current of high - frequency power in the case where the voltage of the high - frequency power supplied to the ultrasonic oscillator is changed in such a way that the current detected by the current sensor becomes constant in the defect detection device of the embodiment shown.

[0067] Figure 15 To represent Figure 12 Flowchart showing the operation of the defect detection device shown.

[0068] Figure 16 To represent in Figure 12 Graph showing a mapping in which the voltage of high - frequency power with respect to the frequency of high - frequency power is pre - specified in such a way that the current of the high - frequency power supplied to the ultrasonic oscillator becomes constant in the defect detection device of the embodiment shown.

[0069] Figure 17 To represent in Figure 12In the defect detection device of the illustrated embodiment, a graph of the change of the voltage of the high-frequency power supply with respect to the frequency of the high-frequency power supply is preliminarily specified so that the current of the high-frequency power supply supplied to the ultrasonic oscillator falls within a predetermined range.

[0070] Figure 18 It is a diagram showing the structure of a defect detection device of another embodiment.

[0071] [Description of symbols]

[0072] 10: Platform

[0073] 10a: Holding surface

[0074] 11: Substrate

[0075] 12: Semiconductor die

[0076] 12a, 14a, 14b: Images

[0077] 12e: Visualized image

[0078] 13: Semiconductor device

[0079] 14: Defective part

[0080] 15: Surface

[0081] 16: Bright part

[0082] 17: Dark part

[0083] 18: Display

[0084] 20, 60: Sonic head

[0085] 21, 211 - 215: Ultrasonic horn

[0086] 21a: Axis

[0087] 22, 62: Housing

[0088] 23: Driving unit

[0089] 24: Ultrasonic wave

[0090] 26, 66: Ball center

[0091] 27: Detection area

[0092] 28: Guide rail

[0093] 29: Slide block

[0094] 29a: Rod

[0095] 30: Laser light source

[0096] 31: Optical axis

[0097] 32: Parallel laser light

[0098] 33: Reflected laser light

[0099] 34a, 34b: Optical paths

[0100] 40: Camera

[0101] 41: Optical axis

[0102] 42: Image pickup element

[0103] 43: Field of view

[0104] 45, 45s, 45v: Image frames

[0105] 46: Pixel

[0106] 47: Vibration - generating pixel

[0107] 48: Array

[0108] 50: Control unit

[0109] 51, 56: CPU

[0110] 52, 57: Storage unit

[0111] 53: Voltage sensor

[0112] 54: Current sensor

[0113] 55: Detection unit

[0114] 58: Display

[0115] 59a, 59b: Mapping

[0116] 63: Spherical zone surface

[0117] 64: Open surface

[0118] 65: Open surface

[0119] 70: Ultrasonic oscillator

[0120] 90: Gap

[0121] 91: Defective area

[0122] 100, 200, 300, 400: Defect detection devices Detailed implementation manners

[0123] <Structure of the defect detection device>

[0124] Hereinafter, on the one hand, referring to the attached Figure 1A description will be given of the defect detection device 100 for the implementation aspect. As Figure 1 shown, the defect detection device 100 includes a stage 10, an acoustic head 20, a laser light source 30, a camera 40, a control unit 50, and a detection unit 55. With respect to Figure 1 the paper surface of, the vertical direction is set as the X direction, the direction orthogonal to the X direction in the horizontal plane is set as the Y direction, and the up-and-down direction is set as the Z direction for description. Furthermore, Figure 1 in, five ultrasonic horns 21 mounted on the housing 22 of the acoustic head 20 are shown. When not distinguishing each ultrasonic horn 21, it is referred to as the ultrasonic horn 21, and when distinguishing each ultrasonic horn 21, it is referred to as ultrasonic horns 211 to 215.

[0125] The stage 10 is mounted on a base (not shown). The stage 10 adsorbs and holds a semiconductor device 13 as an object to be inspected on the upper holding surface 10a. The semiconductor device 13 can be, for example, a device composed of a substrate 11 and a semiconductor die 12 mounted on the substrate 11 through an adhesive, or a device in which the semiconductor die 12 is flip-chip packaged on the substrate 11, or a device in which a plurality of semiconductor dies 12 are stacked on the substrate 11 through direct bonding.

[0126] Figure 1 In the example shown, the semiconductor device 13 has a semiconductor die 12 bonded to the substrate 11 through an adhesive, and a gap 90 caused by a bonding defect is interposed between the upper surface of the substrate 11 and the lower surface of the semiconductor die 12 (refer to Figure 4 ). Furthermore, in the following description, the portion above the gap 90 of the semiconductor die 12 is referred to as the defective portion 14.

[0127] Above one side of the holding surface 10a of the stage 10 and away from the stage 10, the acoustic head 20 is disposed. The acoustic head 20 is composed of a housing 22 and a plurality of ultrasonic horns 21 mounted on the housing 22. The housing 22 of the acoustic head 20 is suspended from a slider 29 by a rod 29a, and the slider 29 is movably mounted in the Y direction on a guide rail 28 provided on the stage 10.

[0128] The housing 22 of the acoustic head 20 is in the shape of a spherical dome and the lower platform side 25 is open. The center of the sphere 26 of the spherical surface forming the housing 22 is located on the surface 15 of the semiconductor device 13 held on the holding surface 10a of the platform 10. The ultrasonic horn 21 is a directional ultrasonic generator that generates ultrasonic waves 24 in a manner that the ultrasonic waves 24 propagate within the range of the directivity angle θ centered on the axis 21a in the direction of the axis 21a. The frequency f of the ultrasonic waves 24 is in the range of several tens of kilohertz (kHz) to about several hundreds of kilohertz. A plurality of ultrasonic horns 21 are mounted on the housing 22 such that the respective axes 21a intersect at the center of the sphere 26 of the spherical surface of the housing 22. Therefore, the respective ultrasonic waves 24 generated from the plurality of ultrasonic horns 21 converge on the surface 15 of the semiconductor device 13 held on the holding surface 10a and located at the center of the sphere 26. The region where the ultrasonic waves 24 converge is the detection region 27 for performing defect detection. As Figure 1 shown, the size of the detection region 27 is larger than the size of the semiconductor die 12, causing the semiconductor die 12 and the substrate 11 to undergo ultrasonic vibration. The ultrasonic horn 21 constitutes an ultrasonic vibrator.

[0129] For each ultrasonic horn 21, a drive unit 23 for driving the ultrasonic horn 21 is respectively connected. Each drive unit 23 supplies high-frequency power to each of the ultrasonic horns 211 to 215 respectively to drive the ultrasonic horns 211 to 215. In addition, each drive unit 23 can respectively adjust the phases of the respective ultrasonic waves 24 generated by the respective ultrasonic horns 211 to 215 connected thereto.

[0130] The drive units 23 for driving the respective ultrasonic horns 21 are connected to the control unit 50 and are driven by the instructions of the control unit 50. The control unit 50 is a computer and includes internally: a central processing unit (CPU) 51, which is a processor for performing information processing; and a storage unit 52, which stores control programs or control data.

[0131] The laser light source 30 converts the laser light of a single wavelength output from the laser oscillator into parallel laser light 32 through a beam expander and irradiates the semiconductor device 13 with the parallel laser light 32 of a single wavelength. Figure 1 In the example shown, the laser light source 30 is mounted on the housing 22 of the acoustic head 20 such that the optical axis 31 obliquely passes through the center of the sphere 26 with respect to the platform 10. That is, the laser light source 30 is mounted on the housing 22 in such a manner that the parallel laser light 32 is irradiated onto the detection region 27 of the surface 15 of the semiconductor device 13 from an obliquely upper direction. The parallel laser light 32 is coherent light with high interference, and the laser light source 30 is a coherent light source for irradiating coherent light. Furthermore, the laser light source 30 may not include a beam expander.

[0132] The camera 40 includes a plurality of pixels 46 (refer toFigure 7 ) The imaging element 42 thus configured captures a two-dimensional image of the semiconductor device 13 irradiated with the parallel laser light 32. Figure 1 In the illustrated embodiment, the camera 40 is mounted on the housing 22 such that the optical axis 41 perpendicularly passes through the center of the sphere 26 with respect to the platform 10. Thus, Figure 1 In the illustrated embodiment, the camera 40 is mounted on the housing 22 so as to capture the detection region 27 on the surface 15 of the semiconductor device 13 from directly above.

[0133] Furthermore, as long as the camera 40 is at a position where it can capture an image of the semiconductor device 13 irradiated with the parallel laser light 32 from the laser light source 30, it may not be directly above the detection region 27, but may be mounted obliquely with respect to the housing 22 in an inclined manner. In addition, the camera 40 can capture a moving image or a still image.

[0134] The laser light source 30 and the camera 40 are connected to the detection unit 55. The detection unit 55 processes the two-dimensional image captured by the camera 40 and detects a defective region 91 (see Figure 8 ). The detection unit 55 is a computer and internally includes: a CPU 56, which is a processor for performing information processing; a storage unit 57, which stores a control program or control data; and a display 58, which displays a visualized image 12e (see Figure 10 ). In addition, the detection unit 55 is connected to the control unit 50 to perform data transfer.

[0135] <Principle of the defective detection operation performed by the defective detection device>

[0136] Hereinafter, on the one hand, with reference to Figures 2 to 8 on the one hand, the principle of the defective detection operation of the defective detection device 100 will be described.

[0137] As Figure 2 shown, minute irregularities exist on the surface 15 of the semiconductor die 12 bonded to the substrate 11. Therefore, if the parallel laser light 32 is irradiated onto the surface 15 of the semiconductor die 12 in a stationary state without ultrasonic excitation of the semiconductor device 13, the parallel laser light 32 is reflected in random directions on the surface 15 of the semiconductor die 12. The reflected laser lights 33 reflected in random directions interfere with each other, and an interference pattern of the reflected laser light 33 appears on the surface of the imaging element 42 of the camera 40.

[0138] Since the interference pattern has bright portions where light is enhanced and dark portions where light is weakened, the imaging element 42 of the camera 40, as Figure 3 shown, acquires the interference pattern in the form of an image 12a of a speckled pattern composed of a plurality of bright portions 16 and dark portions 17 that appears on the surface of the image of the semiconductor die 12.

[0139] Therefore, if the semiconductor die 12 is photographed by the camera 40, the camera 40 obtains an image 12a of the semiconductor die 12 with a speckled pattern as shown in the middle of the Figure 3 field of view 43. The image 12a is an image of the semiconductor die 12 including the interference pattern at rest. In addition, at rest, the defective portion 14 does not undergo ultrasonic vibration, so the camera 40 obtains an image of the interference pattern of the same interference pattern as the other portions as the interference pattern image 14a of the defective portion 14.

[0140] Subsequently, as shown in Figure 4 , each ultrasonic horn 21 is driven by each driving unit 23, and ultrasonic waves 24 of a predetermined frequency f are generated from each ultrasonic horn 21. The ultrasonic waves 24 generated from each ultrasonic horn 21 cross in the detection area 27 near the spherical center 26 of the housing 22, converge and overlap, and ultrasonic excitation is performed on the semiconductor device 13 composed of the substrate 11 and the semiconductor die 12.

[0141] The defective portion 14, which is a defective gap 90, exists between the substrate 11 and the semiconductor die 12 and vibrates significantly with respect to the substrate 11 as shown by the arrow 95 in Figure 4 . On the other hand, the portion of the substrate 11 that is well bonded to the semiconductor die 12, other than the defective portion 14, hardly vibrates with respect to the substrate 11.

[0142] If the defective portion 14 of the semiconductor die 12 vibrates due to ultrasonic excitation, the surface 15 of the semiconductor die 12 vibrates as shown by the arrow 96 in Figure 5 . As a result, the optical path of the reflected laser light 33 reflected by the surface 15 of the defective portion 14 of the semiconductor die 12 flashes between the optical paths 34a and 34b shown in Figure 5 as shown by the arrow 97. The flashing of the optical path 34 including the optical paths 34a and 34b occurs with the same vibration period as the ultrasonic vibration of the semiconductor die 12.

[0143] Due to the flashing of the optical paths 34a and 34b, the image 14a of the defective portion 14 of the semiconductor die 12 with a speckled pattern on the imaging element 42 described in Figure 3 becomes an image 14b that flashes as shown by the arrow 98 in Figure 6 . Here, if the exposure time of the camera 40 is made longer than the vibration period of the ultrasonic vibration of the semiconductor die 12 to photograph the image of the semiconductor die 12, the camera 40 obtains Figure 6 an image 14b of a flashing speckled pattern as shown as the interference pattern image of the defective portion 14.

[0144] On the other hand, the portion of the semiconductor die 12 other than the defective portion 14 that is well-bonded to the substrate 11 hardly vibrates with respect to the substrate 11. Therefore, the image 12a of the portion of the semiconductor die 12 other than the defective portion 14 with a speckled pattern on the imaging element 42 does not flicker. Therefore, the camera 40 acquires a reference Figure 3 The non-flickering speckled pattern image 12a as described is used as an image of the interference pattern of the portion other than the defective portion 14.

[0145] In the defective portion 14 where the image 14b of the interference pattern flickers during exposure, the intensity of the brightness of the pixel 46 of the imaging element 42 changes compared to the intensity of the brightness of the image 14a of the interference pattern in the stationary state or non-vibrating state without ultrasonic vibration. If an example is shown, in the defective portion 14 where the image 14b of the interference pattern flickers, the intensity of the brightness of the pixel 46 becomes larger compared to the image 14a of the interference pattern when not vibrating.

[0146] On the other hand, in the portion other than the defective portion 14 where the image 12a of the interference pattern does not flicker even during ultrasonic excitation during exposure, the image 12a of the interference pattern does not flicker in the same way as the image 12a of the interference pattern when the semiconductor die 12 is in a stationary state or non-vibrating state. Therefore, in the portion other than the defective portion 14, the intensity of the brightness of the pixel 46 of the imaging element 42 is substantially the same as the intensity of the brightness in the stationary state or non-vibrating state where the semiconductor die 12 does not undergo ultrasonic vibration.

[0147] As Figure 7 shown, the detection unit 55 determines the pixel 46 whose intensity of brightness changes when ultrasonic vibration is applied compared to the intensity of brightness at rest or when not vibrating without ultrasonic vibration as the vibration generation pixel 47, and detects the region including the determined vibration generation pixel 47 as the defective region 91 as Figure 8 shown.

[0148] In addition, as Figure 8 shown, the detection unit 55 displays the visualization image 12e on the display 58, and the visualization image 12e is formed by including the display 18 corresponding to the determined vibration generation pixel 47 in the image of the semiconductor die 12. Thus, it is possible to determine the presence or absence of the defective portion 14 based on the display of the display 58.

[0149] <Details of the Defect Detection Operation Performed by the Defect Detection Device>

[0150] <1. Static Image Acquisition Step and Ultrasonic Vibration Image Acquisition Step>

[0151] Subsequently, on the one hand, referring to Figure 9 、 Figure 10 , on the other hand, the details of the operation of the defect detection device 100 of the embodiment will be described.

[0152] As shown Figure 9 in step S101 of, the CPU 56 of the detection unit 55 outputs an irradiation instruction for the parallel laser light 32 to the laser light source 30. According to the instruction, the laser light source 30 irradiates the semiconductor die 12 of the semiconductor device 13 with the parallel laser light 32.

[0153] After starting to irradiate the parallel laser light 32, the CPU 56 of the detection unit 55 enters Figure 9 step S102 of, as shown Figure 2 and Figure 3 in, uses the camera 40 to acquire the images 12a and 14a including the interference pattern, which is generated by the interference of the reflected laser light 33 reflected by the surface 15 of the semiconductor die 12 (static image acquisition step).

[0154] The CPU 56 enters Figure 9 step S103 of, and saves the acquired images 12a and 14a including the interference pattern in the storage unit 57.

[0155] The CPU 56 of the detection unit 55 enters Figure 9 step S104 of, and outputs a signal to start driving the ultrasonic horn 21 to the control unit 50. After inputting the signal, the CPU 51 of the control unit 50 outputs an instruction to start driving the ultrasonic horn 21 to each driving unit 23. Each driving unit 23 drives the ultrasonic horn 21 according to the instruction, so that each ultrasonic horn 21 generates ultrasonic waves 24 with a predetermined frequency f. Each ultrasonic horn 21 has directivity and gradually propagates in the range of the directivity angle θ centered on the axis 21a in the direction of each axis 21a. Since each ultrasonic horn 21 is mounted on the housing 22 in such a way that the axes 21a intersect at the spherical center 26 of the housing 22, the ultrasonic waves 24 generated from each ultrasonic horn 21 cross, concentrate, and overlap near the spherical center 26 of the housing 22.

[0156] Based on the overlap of the ultrasonic waves 24, the CPU 51 of the control unit 50 adjusts the phases of the respective ultrasonic horns 21 through each driving unit 23 in such a way that the amplitude of the ultrasonic vibration becomes larger near the spherical center 26. If an example is shown, the phases of the ultrasonic waves 24 generated by the ultrasonic horns 211 and 215 located at symmetric positions with respect to the spherical center 26 are shifted by 180 degrees. Additionally, as another example, the CPU 51 adjusts through the driving unit 23 in such a way that the phases of the ultrasonic waves 24 generated by the respective ultrasonic horns 211 to 215 are dispersed. Thereby, the amplitude of the ultrasonic vibration in the detection region 27, which is the range where the ultrasonic waves 24 concentrate near the spherical center 26, can be increased.

[0157] Thus, the CPU 51 of the control unit 50 generates ultrasonic waves 24 from the ultrasonic horn 21 through the drive unit 23, and ultrasonically vibrates the semiconductor device 13 composed of the substrate 11 and the semiconductor die 12.

[0158] If the semiconductor device 13 is ultrasonically vibrated, there is a defective portion 14, which is a defective gap 90, between the substrate 11 and the semiconductor die 12. As Figure 4 shown by the arrow 95 in, the semiconductor die 12 vibrates significantly relative to the substrate 11.

[0159] After the CPU 51 of the control unit 50 starts ultrasonic vibration from the ultrasonic horn 21, it outputs the signal during ultrasonic vibration and the frequency f of ultrasonic vibration to the detection unit 55. After the CPU 56 of the detection unit 55 inputs the said signal, in Figure 9 step S105, the exposure time of the camera 40 is set to be longer than the period of ultrasonic vibration, and the camera 40 is used to obtain a reference Figure 6 image 12a and image 14b containing the interference pattern during ultrasonic vibration as described.

[0160] If the image of the semiconductor die 12 is taken with the exposure time of the camera 40 longer than the vibration period of the ultrasonic vibration of the semiconductor die 12, the camera 40 obtains Figure 6 an image 14b of a flickering speckled pattern as shown as the interference pattern image of the defective portion 14. In addition, a non-flickering speckled pattern image 12a as described with reference to Figure 3 is obtained as the interference pattern image of the portion other than the defective portion 14 (ultrasonic vibration image acquisition step).

[0161] After the CPU 56 of the detection unit 55 obtains the images 12a and 14b containing the interference pattern through the camera 40, it enters Figure 9 step S106, and saves the images 12a and 14b containing the interference pattern in the storage unit 57.

[0162] <2. Defect detection step>

[0163] <a. Determination of vibration-generated pixels>

[0164] In Figure 9 step S107, the CPU 56 of the detection unit 55 reads out the images 12a, 14a containing the interference pattern at rest and the images 12a, 14b containing the interference pattern during ultrasonic vibration of the semiconductor die 12 from the storage unit 57, and executes Figure 10In steps S201 to S210, based on the deviation between images 12a and 14a containing the interference pattern at rest and images 12a and 14b containing the interference pattern during ultrasonic vibration, the vibration - generating pixel 47 is determined.

[0165] Hereinafter, on the one hand, with reference to Figure 7 , Figure 10 On the other hand, the details of the determination operation of the vibration - generating pixel 47 will be described in detail. The CPU 56 of the detection unit 55 determines the pixel 46 whose intensity of brightness during ultrasonic vibration changes compared with the intensity of brightness at rest or during non - vibration when ultrasonic vibration is not performed as the vibration - generating pixel 47.

[0166] The CPU 56 of the detection unit 55, as Figure 7 shown, performs the following - described processing on each pixel 46 of the image frame 45, which is a region of the two - dimensional image of the visual field 43 for which image processing is performed at one time, to determine the vibration - generating pixel 47. In the following description, the coordinates (x, y) recorded after the symbol represent the coordinates (x, y) of the two - dimensional image frame 45. For example, pixel 46(x, y) represents the pixel 46 at the coordinates (x, y).

[0167] As Figure 10 shown in step S201, the CPU 56 of the detection unit 55 reads out the image frame 45v during ultrasonic vibration and the image frame 45s at rest from the two - dimensional images during ultrasonic vibration and at rest or during non - vibration acquired by the camera 40 and stored in the storage unit 57.

[0168] As Figure 10 shown in step S202, the CPU 56 calculates the average value Ia(x, y) of the intensity Iv(x, y) of brightness during ultrasonic vibration and the intensity Is(x, y) of brightness at rest for each pixel 46(x, y).

[0169] Average value Ia(x, y) = [Iv(x, y)+Is(x, y)] / 2

[0170] As Figure 10 shown in step S203, the CPU 56 calculates the average value of the absolute value of the deviation between the intensity Iv(x, y) of brightness during ultrasonic vibration and the average value Ia(x, y) for each pixel 46(x, y) as the average absolute deviation for the image frame 45.

[0171] Average absolute deviation =

[0172] Average value in the image frame 45 of |Iv(x, y) - Ia(x, y)|

[0173] As Figure 10As shown in step S204, the CPU 56 calculates the fourth power value NIave(x, y) of the normalized pixel intensity through the following (Equation 1).

[0174] NIave(x, y) =

[0175] [|Iv(x, y) - Ia(x, y)| / average absolute deviation] 4 (Equation 1)

[0176] As Figure 10 shown in step S205, when NIave(x, y) is 1 or more, the CPU 56 determines that the change in the intensity of the brightness of the pixel 46(x, y) is significant, enters Figure 10 step S206, determines the pixel 46(x, y) as the vibration generating pixel 47(x, y), and enters step S207. When the CPU 56 determines in step S207 that not all pixels 46(x, y) of the image frame 45 have been processed, it returns to step S204 to process the next pixel 46(x, y). On the other hand, when the CPU 56 Figure 10 determines in step S205 that it is NO, it returns to step S204 to process the next pixel 46(x, y). After the CPU 56 calculates NIave(x, y) for all pixels 46(x, y) of the image frame 45 and determines the vibration generating pixels 47(x, y) in the image frame 45, in Figure 10 step S207, when it determines that it is YES, it enters Figure 10 step S208.

[0177] Figure 10 In step S208, the CPU 56 confirms whether there are a predetermined number of other vibration generating pixels 47(x1, y1) within a predetermined range around a vibration generating pixel 47(x, y). For example, an array 48 of 5×5 pixels 46 centered on the vibration generating pixel 47(x, y) can be set as the predetermined range, and it is confirmed whether there are 7 to 8 other vibration generating pixels 47(x1, y1) therein. Moreover, when Figure 10 it determines in step S208 that it is YES, it determines that the change in the intensity of the brightness of the pixel 46(x, y) is caused by ultrasonic vibration, enters Figure 10 step S209, and maintains the determination of the pixel 46(x, y) as the vibration generating pixel 47(x, y).

[0178] On the other hand, when there are not 7 to 8 other vibration generating pixels 47(x1, y1) in the array 48, it determines that the change in the intensity of the brightness of the pixel 46(x, y) is not caused by ultrasonic vibration, and enters Figure 10In step S210, the determination of generating pixel 47 by canceling the vibration of pixel 46(x, y) is cancelled.

[0179] Moreover, the CPU 56 implements the determination of generating pixel 47 by vibration. The CPU 56 performs the above processing in each image frame 45, and implements the determination of generating pixel 47 by vibration for all pixels 46(x, y) of the imaging element 42.

[0180] <b. Defect detection>

[0181] The CPU 56 of the detection unit 55 executes Figure 9 step S107 of Figure 10 After determining the generating pixel 47 by vibration through steps S201 to S210 of Figure 9 it enters step S108 of Figure 9 setting the area where the generating pixels 47 determined by step S107 of

[0182] In the imaging element 42 are concentrated to a value equal to or greater than a predetermined value as a defective area 91. Figure 7 Regarding the method of setting the defective area 91, there are many methods. For example, when the number of generating pixels 47 in the 5×5 pixel 46 square array 48 described in

[0183] is equal to or greater than a predetermined value, the array 48 is set as a generating array, and the area where the generating arrays are continuous is set as the defective area 91. At this time, the predetermined value can also be determined through tests, etc. For example, half of the number of pixels 46 included in the array 48 can be set as the predetermined value, or the predetermined value can be set between 30% and 70%. In addition, the number of pixels 46 included in the array 48 can be 5×5 = 25 as described above, or can be set to 100×100 = 10000.

[0184] In addition, the established threshold value can also vary according to the region where the vibration generation array is continuous. For example, in the semiconductor device 13 directly bonded with a plurality of semiconductor chips 12, the established threshold value can be set smaller than other parts around the electrodes of the upper and lower semiconductor chips 12 to strictly inspect the bonding between the electrodes. In addition, the established threshold value can be reduced around the semiconductor chip 12 and increased in the center, or conversely, the established threshold value can be increased around the semiconductor chip 12 and set small in the center.

[0185] As described above, examples of setting the defective region 91 have been explained. However, as long as a region where the vibration generation pixels 47 in the imaging element 42 are concentrated to a value equal to or greater than a predetermined value can be set, it is not limited to the method described above. For example, the defective region 91 can also be set by image analysis of the distribution image of the vibration generation pixels 47 of the good semiconductor device 13 and the distribution image of the vibration generation pixels 47 of the semiconductor device 13 to be inspected.

[0186] After setting the defective region 91 is completed, the CPU 56 of the detection unit 55 proceeds to Figure 9 step S109 to determine whether the defective region 91 can be set. When the CPU 56 of the detection unit 55 determines YES in Figure 9 step S109, in Figure 9 step S110, a defective detection signal is output to the outside. At this time, information on the position and shape of the defective region 91 can also be output to the outside.

[0187] In addition, when the CPU 56 of the detection unit 55 determines NO in Figure 9 step S109, it is determined that no defect is detected, and in Figure 9 step S111, a good product detection signal indicating that the semiconductor device 13 to be inspected is a good product is output.

[0188] <3. Display step>

[0189] As shown in Figure 8 , in Figure 9 step S112, the CPU 56 of the detection unit 55 displays the visualization image 12e on the display 58, and the visualization image 12e is formed by including the display 18 corresponding to the determined vibration generation pixels 47 in the image of the semiconductor chip 12 (display step).

[0190] The visualization image 12e can be set in various forms. Figure 8As an example, the following image is set, that is: on the image of the normal semiconductor die 12 obtained by irradiating the semiconductor die 12 with non-interfering light such as an electric lamp, at the part corresponding to the vibration generating pixel 47, red dots are overlapped as the display 18. According to the said image, in the area near the defective part 14 vibrating due to ultrasonic vibration, a large number of red dots as the display 18 are shown, and in the part other than the non-vibrating defective part 14, almost no red dots as the display 18 are shown. Figure 8 In the example shown, it can be known that in the central part of the semiconductor die 12 where a large number of red dots as the display 18 are shown, there is a gap 90 that constitutes the defective part 14 that undergoes ultrasonic vibration due to ultrasonic excitation, and there is no gap 90 in other parts. Therefore, by visually recognizing the visualized image 12e displayed on the display 58, it is possible to detect whether there is a gap 90 as a defect in the semiconductor device 13. It should be noted that the red dots as the display 18 are shown as black dots Figure 8 in.

[0191] In addition, the CPU 56 of the detection unit 55 can also Figure 9 the defective area 91 set in step S108 is overlapped and displayed on the visualized image 12e. Thus, the defective area 91 and the display 18 are overlapped and displayed on the image of the normal semiconductor die 12, and it can be confirmed whether the defective detection has been performed.

[0192] <Function / Effect of the Defect Detection Device 100>

[0193] As described above, the defect detection device 100 of the embodiment irradiates the semiconductor device 13 with parallel laser light 32 for ultrasonic excitation, and performs defect detection based on the deviation between the images 12a, 14a including the interference pattern at rest and the images 12a, 14b including the interference pattern during ultrasonic excitation. Therefore, the defect of the semiconductor device 13 can be detected in a short time with a simple structure.

[0194] In addition, when there are a predetermined number of other vibration generating pixels 47(x1, y1) within a predetermined range around one vibration generating pixel 47(x, y) of the defect detection device 100, it is determined that the change in the intensity of the brightness of the pixel 46(x, y) is caused by ultrasonic vibration, and the determination of the pixel 46(x, y) as the vibration generating pixel 47(x, y) is maintained, and when this is not the case, the determination as the vibration generating pixel 47(x, y) is cancelled. Thereby, it is possible to suppress the determination of pixels 46 that do not actually vibrate as vibration generating pixels 47 due to noise, and perform vibration detection and defect detection with high precision.

[0195] In addition, the defect detection device 100 sets the area where the vibration - generating pixels 47 determined are concentrated to a value equal to or greater than a predetermined value as the defective area 91 to detect defects. Therefore, defects can be detected based on the deviation between the images 12a and 14a including the interference pattern at rest and the images 12a and 14b including the interference pattern during ultrasonic excitation.

[0196] In addition, the defect detection device 100 displays the visualization image 12e that visualizes the defective part 14 on the display 58. Therefore, it is possible to simply determine whether there is a defect by only looking at the display 58.

[0197] In addition, the defect detection device 100 of the embodiment uses the acoustic head 20 equipped with a plurality of ultrasonic horns 21 to concentrate the ultrasonic wave 24 on the semiconductor device 13, and indirectly excites the semiconductor device 13 with ultrasonic waves to detect defects. Therefore, defects can be detected using a simple structure. In addition, since the semiconductor device 13 is indirectly excited by ultrasonic waves, the defect detection of the semiconductor device 13 can be performed in a non - contact manner.

[0198] <Modification Example of the Defect Detection Device 100>

[0199] In the above description, it is assumed that the laser light source 30 irradiates the semiconductor device 13 with parallel laser light 32 of a single wavelength, but this is not limited thereto. The wavelength may have a slight range, and non - parallel laser light may be irradiated. In addition, the intensity of the laser light may have a slight non - uniformity. In the above description, regarding the images 12a, 14a, and 14b of the interference pattern, a speckle pattern including a plurality of bright parts 16 and dark parts 17 has been described, but this is not limited thereto, and other patterns such as a fringe pattern may also be used.

[0200] In addition, when the vibration direction of the semiconductor device 13 is not in one direction, a plurality of laser light sources 30 and cameras 40 may be prepared, laser light may be irradiated on the semiconductor device 13 from multiple directions, and images may be captured from multiple directions using the plurality of cameras 40, thereby detecting vibrations in multiple directions to perform defect detection.

[0201] In the above description, the semiconductor device 13 has been described as the object to be inspected, but it can also be applied to the detection of inter - layer bonding defects of other products in which plate - like members are laminated and bonded. Examples of other products in which plate - like members are laminated and bonded include laminated boards and laminates.

[0202] <Another Embodiment 1>

[0203] Next, while referring to Figure 11 while explaining the defect detection device 200 of another embodiment. For the same as those referred to above Figures 1 to 10Parts that are the same as the parts described are marked with the same symbols and the description is omitted.

[0204] As Figure 11 shown, in the defect detection device 200 of the embodiment, a sonic head 60 in which a plurality of ultrasonic horns 21 are mounted on an annular housing 62 constitutes the sonic head 20 of the defect detection device 100 described with reference to Figure 1 above.

[0205] As Figure 11 shown, the housing 62 is a frustum-shaped annular member, with a small-diameter open surface 64 on the upper side and a large-diameter open surface 65 on the lower side, and a plurality of ultrasonic horns 21 are mounted on the spherical zone surface 63. The center 66 of the spherical zone surface 63 is located on the surface 15 of the semiconductor device 13 held on the holding surface 10a of the stage 10. The plurality of ultrasonic horns 21 are mounted on the housing 62 such that their respective axes 21a intersect at the center 66 of the spherical surface of the housing 62. Similar to the defect detection device 100 described with reference to Figure 1 above, the ultrasonic waves 24 generated from each ultrasonic horn 21 intersect, converge, and overlap at the center 66 of the sphere. By the overlap of the ultrasonic waves 24, a detection region 27 with a large amplitude of ultrasonic vibration is formed near the center 66 of the sphere.

[0206] The operation of the defect detection device 200 is the same as that of the defect detection device 100 described with reference to Figure 1 above.

[0207] Since the housing 62 of the defect detection device 200 is composed of a frustum-shaped annular member and a top plate 67, the thickness in the Z direction can be reduced, and it can be incorporated into a small bonding device or the like.

[0208] <Other Embodiment 2>

[0209] Next, while referring to Figures 12 to 17 while, the defect detection device 300 as another embodiment will be described. In the defect detection device 300, instead of the sonic head 20 of the defect detection device 100 described with reference to Figure 1 above, the semiconductor device 13 is ultrasonically excited by an ultrasonic vibrator 70 connected to the semiconductor device 13. The ultrasonic vibrator 70 constitutes an ultrasonic exciter. The structures of the laser light source 30, the camera 40, and the detection unit 55 are the same as those of the defect detection device 100 described above.

[0210] The ultrasonic oscillator 70 is driven by a drive unit 23 that supplies high-frequency power to the ultrasonic oscillator 70. The ultrasonic oscillator 70 may also be constituted by a piezoelectric element or the like, for example. Between the drive unit 23 and the ultrasonic oscillator 70, a voltage sensor 53 that detects the voltage of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 and a current sensor 54 that detects the current of the high-frequency power are installed. The voltage sensor 53 and the current sensor 54 are connected to the control unit 50, and the data of the voltage and current of the high-frequency power detected by the voltage sensor 53 and the current sensor 54 are input to the control unit 50. The control unit 50 changes the frequency of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 while using the camera 40 to capture an image of the semiconductor device 13, and performs defect detection of the semiconductor device 13 based on the captured image.

[0211] Before explaining the operation of the defect detection device 300 of the embodiment, while referring to Figure 13 , while explaining the changes in the impedance and current A0 with respect to the frequency f in the case where the voltage V0 of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 is set to be constant as in the prior art.

[0212] As Figure 13 shown by the dash-dot line c0, if the voltage V0 of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 is set to be constant and the frequency f of the high-frequency power is changed, the ultrasonic oscillator 70 itself resonates at the frequency f1. Thus, the impedance of the ultrasonic oscillator 70 decreases significantly at the frequency f1 as shown by the dashed line a in Figure 13 . On the other hand, at the frequency f2 between the resonance frequency f1 and the maximum frequency f3, the impedance of the ultrasonic oscillator 70 increases significantly.

[0213] If the impedance of the ultrasonic oscillator 70 decreases significantly near the frequency f1 as shown by the dashed line a in Figure 13 , then as shown by the solid line b0 in Figure 13 , the current A0 of the high-frequency power supplied to the ultrasonic oscillator 70 increases significantly. Conversely, if the impedance of the ultrasonic oscillator 70 increases significantly near the frequency f2, the current A0 of the high-frequency power supplied to the ultrasonic oscillator 70 decreases significantly. The magnitude of the current A0 supplied to the ultrasonic oscillator 70 is proportional to the amplitude of the ultrasonic oscillator 70. Therefore, near the frequency f1 at which the ultrasonic oscillator 70 resonates, the amplitude of the ultrasonic oscillator 70 increases significantly and the amplitude of the substrate 11 increases significantly, and near the frequency f2, the amplitude of the ultrasonic oscillator 70 decreases significantly and the amplitude of the substrate 11 decreases significantly.

[0214] Therefore, at the resonance frequency f1 of the ultrasonic oscillator 70, both the substrate 11 and the semiconductor die 12 vibrate significantly. Thus, sometimes the vibration of the defective portion 14 of the semiconductor die 12 is masked by the vibrations of the substrate 11 and the semiconductor die, making it difficult to detect.

[0215] Conversely, at the frequency f2, the vibrations of the substrate 11 and the semiconductor die 12 become very small, and sometimes the vibration of the defective portion 14 of the semiconductor die 12 cannot be detected.

[0216] As described above, when the voltage V0 supplied from the drive unit 23 to the ultrasonic oscillator 70 is set to be constant and the frequency is changed as in the prior art, sometimes it is difficult to detect the defective portion 14 of the semiconductor die 12 near the resonance frequency f1 of the ultrasonic oscillator 70.

[0217] Therefore, in the defective detection device 300 of the embodiment, focusing on the fact that the amplitude of the ultrasonic oscillator 70 is proportional to the current of the high-frequency power supplied to the ultrasonic oscillator 70, the current sensor 54 is used to detect the current A1 of the high-frequency power supplied to the ultrasonic oscillator 70, and the voltage V1 of the high-frequency power is adjusted so that the detected current A1 is within a predetermined range. Thus, the current A1 of the high-frequency power can be set within a predetermined range and the amplitude of the ultrasonic oscillator 70 can be set within a predetermined range. Moreover, the following situation is suppressed, that is, when the frequency of the high-frequency power is changed to ultrasonically excite the semiconductor device 13, the substrate 11 or the semiconductor die 12 vibrates significantly at a specific frequency, and the vibration of the defective portion 14 cannot be detected due to being masked by the vibration of the substrate 11 or the semiconductor die 12.

[0218] Hereinafter, while referring to Figure 14 while, in the defective detection device 300 of the embodiment, the case where the voltage V1 of the high-frequency power supplied to the ultrasonic oscillator 70 is changed so that the current A1 detected by the current sensor 54 becomes constant, the change of the voltage V1 of the high-frequency power and the change operation of the current A1 will be described.

[0219] In the defective detection device 300 of the embodiment, the current A1 detected by the current sensor 54 is fed back to the control unit 50. Near the frequency f1 where the current A1 of the high-frequency power increases, as shown by the dashed line c1 in Figure 14 , the voltage V1 of the high-frequency power supplied to the ultrasonic oscillator 70 is decreased. On the other hand, near the frequency f2 where the current A1 detected by the current sensor 54 decreases, as shown by the dashed line c1 in Figure 14 , the voltage V1 of the high-frequency power supplied to the ultrasonic oscillator 70 is increased. Thus, as shown by the solid line d1 in Figure 14 , the magnitude of the current A1 detected by the current sensor 54 can be made substantially constant regardless of the frequency f.

[0220] Thus, by performing feedback control such that the current A1 of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 becomes substantially constant, even when the frequency f of the high-frequency power is changed, the amplitude of the ultrasonic oscillator 70 can be made substantially constant, and the vibrations of the substrate 11 and the semiconductor die 12 can be made substantially constant. Thereby, the following situation can be suppressed, that is, when the semiconductor device 13 is ultrasonically excited by changing the frequency of the high-frequency power, the substrate 11 or the semiconductor die 12 vibrates greatly at a specific frequency, and the vibration of the defective portion 14 cannot be detected due to being shielded by the vibration of the substrate 11 or the semiconductor die 12.

[0221] Subsequently, on the one hand, referring to Figure 15 On the other hand, the defect detection of the semiconductor device 13 performed by the defect detection device 300 of the embodiment will be described. For the steps of the same operations as those of the defect detection device 100 described above with reference to Figure 9 the same step symbols are assigned and the description is omitted.

[0222] As shown in steps S101 to S103 of Figure 15 the detection unit 55 irradiates the semiconductor device 13 with the parallel laser light 32, acquires the images 12a and 14a of the interference pattern at rest, and stores them in the storage unit 57.

[0223] After the detection unit 55 stores the images 12a and 14a of the interference pattern at rest in the storage unit 57, it outputs a signal to start driving the ultrasonic oscillator 70 to the control unit 50. After the CPU 51 of the control unit 50 inputs the said signal, as in Figure 15 step S304 of

[0224] it outputs an instruction to start driving the ultrasonic oscillator 70 to the drive unit 23. The drive unit 23 drives the ultrasonic oscillator 70 according to the said instruction, causing the semiconductor device 13 to perform ultrasonic vibration. Figure 15 As in

[0225] step S304 of Figure 15In step S105, the exposure time of the camera 40 is set to be longer than the period at the start frequency f0 of the ultrasonic vibration, and the reference is acquired using the camera 40. Figure 6 The images 12a and 14b including the interference pattern during ultrasonic vibration, as described, Figure 15 In step S106, the images 14a and 14b are saved in the storage unit 57. The camera 40 can capture the images 12a, 14a, and 14b in the form of a moving image and save the moving image data in the storage unit 57, or can capture the images 12a, 14a, and 14b in the form of a still image every time the frequency f of the ultrasonic excitation changes by a fixed frequency Δf, and save a data set of multiple still images in the storage unit 57.

[0226] Similar to the defect detection device 100 described above, the CPU 56 of the detection unit 55 Figure 15 determines the vibration generation pixels 47 in step S107, Figure 15 and sets the region where the vibration generation pixels 47 are concentrated to a value equal to or greater than a predetermined value as the defective region 91 in step S108. Then, Figure 15 when it is determined to be YES in step S109, Figure 15 a defect detection signal is output in step S110, and Figure 15 when it is determined to be NO in step S109, Figure 15 a non-defective product detection signal is output in step S111. Then, Figure 15 the visualization image 12e is displayed on the display 58 in step S112.

[0227] As described above, when the defect detection device 300 of the embodiment ultrasonically excites the semiconductor device 13 by changing the frequency of the high-frequency power, the amplitude of the ultrasonic oscillator 70 is set within a predetermined range, and the substrate 11 or the semiconductor die 12 can be suppressed from vibrating greatly at a specific frequency. Thereby, the vibration of the defective portion 14 that cannot be detected due to being masked by the vibration of the substrate 11 or the semiconductor die 12 at a specific frequency can be suppressed, and the detection accuracy of the defective portion 14 can be improved.

[0228] In addition, similar to the defect detection device 100, the defect detection device 300 ultrasonically excites the semiconductor device 13 and performs defect detection based on the deviation between the images 12a and 14a including the interference pattern at rest and the images 12a and 14b including the interference pattern during ultrasonic excitation. Therefore, the defect detection of the semiconductor device 13 can be performed in a short time using a simple structure.

[0229] In the above description, the following case has been described, that is, by performing feedback control so that the current A1 of the high-frequency power supplied from the drive unit 23 to the ultrasonic oscillator 70 becomes substantially constant, the amplitude of the ultrasonic oscillator 70 is made substantially constant when the frequency f of the high-frequency power changes, but it is not limited thereto.

[0230] For example, as described with reference to Figure 13 By performing experiments or the like, the change in the current A0 of the high-frequency power when the voltage V0 of the high-frequency power is kept constant and the frequency is changed is obtained in advance. As shown by the one-dot chain line c2 in Figure 16 a voltage waveform in which the increase and decrease of the current A0 are opposite to each other is generated, and the voltage waveform is stored in the storage unit 52 in advance as a map 59a showing the change of the voltage V2 with respect to the frequency f. As shown by the one-dot chain line c2 in Figure 16 the map 59a has a waveform in which the voltage decreases near the frequency f1 and increases at the frequency f2. Further, when performing ultrasonic excitation, the voltage with respect to the frequency f may also be adjusted with reference to the map 59a stored in the storage unit 52. In this case, as shown by the solid line d2 in Figure 16 even if the frequency changes, the current A2 supplied to the ultrasonic oscillator 70 becomes substantially constant.

[0231] Accordingly, it is possible to suppress, with a simple configuration, the following situation: when the semiconductor device 13 is ultrasonically excited in various frequency bands, the entire semiconductor device 13 vibrates greatly, and the vibration of the defective part 14 is masked by the vibration of the substrate 11 or the semiconductor die 12 and cannot be detected, and the defect of the semiconductor device 13 can be detected with high precision.

[0232] In addition, the experiment can be made simpler. For example, Figure 17 as shown by the one-dot chain line c3 in Figure 17 a voltage waveform in which the voltage V3 changes stepwise with respect to the frequency f is stored in the storage unit 52 as a map 59b. In this case, as shown by the solid line d3 in

[0233] <Other Embodiment 3>

[0234] Next, the defective detection device 400 of another embodiment will be described while referring to Figure 18 while referring to the defective detection device 100 described with reference to Figure 1 between each drive unit 23 and each ultrasonic horn 21 (ultrasonic horns 212 to 215) of the defective detection device 100 described with reference to Figures 12 to 17Similarly, a voltage sensor 53 and a current sensor 54 are respectively installed in the described defect detection device 300. Furthermore, Figure 18 Only one ultrasonic horn 211 installed on the acoustic head 20 is shown in the figure, and the illustration of other ultrasonic horns 212 to 215 is omitted. In addition, only the vicinity of the ultrasonic horn 211 is shown for the housing 22, and the illustration of other parts is omitted.

[0235] The operation of the defect detection device 400 is the same as that of the defect detection device 300 except for the following aspects: instead of driving the ultrasonic oscillator 70 using the drive unit 23, each ultrasonic horn 21 is driven using a plurality of drive units 23.

[0236] The defect detection device 400 performs feedback control so that the current A1 of the high-frequency power supplied from each drive unit 23 to each ultrasonic horn 21 becomes substantially constant. Thus, even when the frequency f of the high-frequency power is changed, the ultrasonic excitation force of each ultrasonic horn 21 on the semiconductor device 13 is made substantially constant, and the vibrations of the substrate 11 and the semiconductor die 12 are made substantially constant. Thereby, similar to the defect detection device 300, the following situation can be suppressed, that is: when the semiconductor device 13 is ultrasonically excited by changing the frequency of the high-frequency power, the substrate 11 or the semiconductor die 12 vibrates greatly at a specific frequency, and the vibration of the defective part 14 cannot be detected due to being masked by the vibration of the substrate 11 or the semiconductor die 12.

[0237] In addition, similar to the defect detection device 100, the defect detection device 400 ultrasonically excites the semiconductor device 13 and performs defect detection based on the deviation between the images 12a, 14a including the interference pattern at rest and the images 12a, 14b including the interference pattern during ultrasonic excitation. Therefore, the defect detection of the semiconductor device 13 can be performed in a short time using a simple structure. In addition, since the semiconductor device 13 is ultrasonically excited indirectly, the defect detection of the semiconductor device 13 can be performed in a non-contact manner.

[0238] <Vibration Detection Device>

[0239] Regarding the defect detection devices 100, 200, 300, and 400 described above, it is assumed that a defective area 91 is set and the defect detection of the semiconductor device 13 as the object to be inspected is performed. However, it can also function as the following vibration detection device, that is, not execute Figure 9 Steps S108 to S111 or Figure 15 Steps S108 to S111, display the vibration generation pixels indicating the vibration generation site on the display 58, and determine the vibration site of the semiconductor device 13 as the object to be inspected.

[0240] When the defect inspection device 100 functions as a vibration detection device, the detection unit 55 processes the image captured by the camera 40 to determine vibration generation pixels 47 indicating vibration generation sites, and displays a visualization image 12e on the display 58, where the visualization image 12e is formed by including, in the image of the semiconductor device 13, a display corresponding to the determined vibration generation pixels 47.

[0241] When the defect inspection device 100 functions as a vibration detection device, for the determination of whether there is a defect, an inspector visually judges the image on the display 58.

[0242] This kind of operation is useful, for example, when there is a new semiconductor device 13 and there is no threshold value or established value for setting the defective area 91.

Claims

1. A defect detection device for detecting defects in an object to be inspected, characterized in that Comprising: An ultrasonic vibrator for ultrasonically vibrating the inspection object; A coherent light source for irradiating the inspection object with coherent light; A camera having an imaging element that captures an image of the inspection object irradiated with the coherent light; And A detection unit for performing defect detection of the inspection object based on the image captured by the camera, When the camera performs shooting, the exposure time is longer than the period of the ultrasonic vibration of the inspection object, and an image including an interference pattern is obtained. The interference pattern is generated by the interference of the coherent light reflected from the surface of the inspection object, The detection unit determines vibration-generated pixels based on the deviation between an image including the interference pattern of the inspection object at rest and an image including the interference pattern of the inspection object during ultrasonic vibration, and sets a region where the determined vibration-generated pixels are concentrated to a value equal to or greater than a predetermined value as a defective region to detect defects, where the image including the interference pattern of the inspection object at rest and the image including the interference pattern of the inspection object during ultrasonic vibration are obtained by the camera.

2. The defect detection device according to claim 1, characterized in that When a predetermined number of other vibration-generated pixels exist within a predetermined range around the determined vibration-generated pixels, the detection unit maintains the determination of the vibration-generated pixels of the pixel, and when a predetermined number of vibration-generated pixels do not exist within the predetermined range, the detection unit cancels the determination of the vibration-generated pixels of the pixel.

3. The defective detection device according to claim 1 or 2, characterized in that Comprising: A display for displaying an image of the inspection object, The detection unit displays a visualized image on the display, and the visualized image is formed by making the image of the inspection object include a display corresponding to the determined vibration-generated pixels.

4. The defect detection device according to claim 1 or 2, characterized in that The coherent light is laser light, The coherent light source irradiates the inspection object with parallel laser light of a single wavelength.

5. The defective detection device according to claim 1 or 2, characterized in that Comprising: A drive unit for supplying high-frequency power to the ultrasonic vibrator; And A control unit for adjusting the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, When the detection unit performs defect detection of the inspection object, the control unit changes the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator.

6. The defective detection device according to claim 5, wherein Comprising: A current sensor for detecting the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, When the control unit changes the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, the control unit adjusts the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator so that the current detected by the current sensor falls within a predetermined range.

7. The defect detection device according to claim 5, characterized in that The control unit includes: a mapping that prescribes in advance the change of the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator with respect to the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator in such a manner that the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator falls within a predetermined range. When changing the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator is adjusted based on the mapping.

8. The defect detection device according to claim 1 or 2, wherein the ultrasonic vibrator is an ultrasonic horn or an ultrasonic oscillator, the ultrasonic horn is disposed around the inspection object, and the ultrasonic oscillator is connected to the inspection object to cause the inspection object to perform ultrasonic vibration.

9. The defect detection device according to claim 1 or 2, wherein the ultrasonic vibrator is composed of a plurality of ultrasonic horns having directivity and disposed around the inspection object, and the plurality of ultrasonic horns are mounted on a housing in such a manner that a plurality of ultrasonic waves generated from each ultrasonic horn are concentrated on the inspection object.

10. The defective detection device according to claim 9, wherein including: a plurality of drive units that respectively supply high-frequency power to the plurality of ultrasonic horns; and a control unit that adjusts the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn, wherein the control unit changes the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn when the detection unit performs defect detection on the inspection object.

11. The defective detection device according to claim 10, characterized in that including: current sensors that respectively detect the current of the high-frequency power supplied from each drive unit to each ultrasonic horn, wherein the control unit adjusts the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn in such a manner that the current detected by each current sensor falls within a predetermined range when changing the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn.

12. The defect detection device according to claim 10, wherein the control unit includes: a mapping that prescribes in advance the change of the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn with respect to the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn in such a manner that the current of the high-frequency power supplied from each drive unit to each ultrasonic horn respectively falls within a predetermined range, and when changing the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn, the voltage of the high-frequency power supplied from each drive unit to each ultrasonic horn is adjusted based on the mapping.

13. The defect detection device according to claim 10, wherein the control unit adjusts the phases of the ultrasonic waves generated by each ultrasonic horn through each drive unit respectively.

14. A defect detection method for detecting defects in an object to be inspected, characterized in that including: Static image acquisition step: irradiate the inspection object with coherent light, use a camera to photograph the inspection object, and acquire an image of the inspection object at rest; Ultrasonic vibration image acquisition step: while irradiating the inspection object with the coherent light, ultrasonically vibrate the inspection object by an ultrasonic vibrator, use the camera to photograph the inspection object, and photograph an image of the inspection object during ultrasonic vibration; And Defect detection step: based on the deviation between the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration, perform defect detection on the inspection object, wherein the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration are acquired by the camera; The static image acquisition step acquires an image including an interference pattern at rest, and the interference pattern at rest is generated by the interference of the coherent light reflected by the surface of the inspection object; The ultrasonic vibration image acquisition step makes the exposure time of the camera longer than the period of the ultrasonic vibration of the inspection object, and uses the camera to acquire an image including an interference pattern during ultrasonic vibration, and the interference pattern during ultrasonic vibration is generated by the interference of the coherent light reflected by the surface of the inspection object; The defect detection step determines vibration-generated pixels based on the deviation between the image including the interference pattern at rest of the inspection object and the image including the interference pattern during ultrasonic vibration of the inspection object, sets the area where the determined vibration-generated pixels are concentrated to a value equal to or higher than a predetermined value as a defective area, and detects defects, wherein the image including the interference pattern at rest of the inspection object and the image including the interference pattern during ultrasonic vibration of the inspection object are acquired by the camera.

15. The defect detection method according to claim 14, wherein In the defect detection step, when a predetermined number of other vibration-generated pixels exist within a predetermined range around the determined vibration-generated pixel, the determination of the vibration-generated pixel of the pixel is maintained, and when the predetermined number of vibration-generated pixels does not exist within the predetermined range, the determination of the vibration-generated pixel of the pixel is canceled.

16. The defective detection method according to claim 14 or 15, characterized in that Further includes: Display step: display a visualization image on a display, and the visualization image is formed by making the image of the inspection object include a display corresponding to the determined vibration-generated pixels.

17. A defect detection device for detecting defects in an object to be inspected, characterized in that Includes: An ultrasonic vibrator that ultrasonically vibrates the inspection object; A drive unit that supplies high-frequency power to the ultrasonic vibrator; A current sensor that detects the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator; A control unit that adjusts the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator; A coherent light source that irradiates the inspection object with coherent light; A camera having an imaging element that photographs the inspection object irradiated with the coherent light to acquire an image; And The inspection unit performs defect inspection of the inspection object based on the deviation between the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration, wherein the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration are acquired by the camera. When the inspection unit performs defect inspection of the inspection object, the control unit changes the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator. When the frequency of the high-frequency power changes, the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator is adjusted so that the current detected by the current sensor falls within a predetermined range.

18. A defect detection device for detecting defects in an object to be inspected, characterized in that Comprising: An ultrasonic vibrator that ultrasonically vibrates the inspection object; A drive unit that supplies high-frequency power to the ultrasonic vibrator; A control unit that adjusts the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator; A coherent light source that irradiates the inspection object with coherent light; A camera having an imaging element that captures an image of the inspection object irradiated with the coherent light; And An inspection unit that performs defect inspection of the inspection object based on the deviation between the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration, wherein the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration are acquired by the camera. The control unit includes a map that prescribes in advance the change of the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator with respect to the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator so that the current of the high-frequency power supplied from the drive unit to the ultrasonic vibrator falls within a predetermined range. When changing the frequency of the high-frequency power supplied from the drive unit to the ultrasonic vibrator, the voltage of the high-frequency power supplied from the drive unit to the ultrasonic vibrator is adjusted based on the map.

19. A defective detection device for detecting defects in an object to be inspected, characterized in that Comprising: An ultrasonic vibrator composed of a plurality of ultrasonic horns arranged around the inspection object and having directivity. The plurality of ultrasonic horns are mounted on a housing in such a manner that a plurality of ultrasonic waves generated from each ultrasonic horn are concentrated on the inspection object, and ultrasonically vibrate the inspection object; A plurality of drive units that respectively supply high-frequency power to the plurality of ultrasonic horns; Current sensors that respectively detect the current of the high-frequency power supplied from each drive unit to each ultrasonic horn; A control unit that adjusts the frequency of the high-frequency power supplied from each drive unit to each ultrasonic horn; A coherent light source that irradiates the inspection object with coherent light; A camera having an imaging element that captures an image of the inspection object irradiated with the coherent light; And The inspection unit performs defect inspection of the inspection object based on the deviation between the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration, where the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration are captured by the camera. When the inspection unit performs defect inspection of the inspection object, the control unit changes the frequency of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns. When the frequency of the high-frequency power changes, the voltage of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns is adjusted so that the current detected by each of the current sensors falls within a predetermined range.

20. A defect detection device for detecting defects in an object to be inspected, characterized in that Comprising: An ultrasonic exciter composed of a plurality of ultrasonic horns arranged around the inspection object and having directivity. The plurality of ultrasonic horns are mounted on a housing in such a way that a plurality of ultrasonic waves generated from each ultrasonic horn are concentrated on the inspection object, and the inspection object is ultrasonically excited. A plurality of drive units that respectively supply high-frequency power to the plurality of ultrasonic horns. A control unit that adjusts the frequency of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns. A coherent light source that irradiates coherent light onto the inspection object. A camera having an imaging element that captures an image of the inspection object irradiated with the coherent light. And An inspection unit that performs defect inspection of the inspection object based on the deviation between the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration, where the image of the inspection object at rest and the image of the inspection object during ultrasonic vibration are captured by the camera. The control unit includes a map that prescribes in advance the change in the voltage of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns with respect to the frequency of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns so that the current of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns respectively falls within a predetermined range. When changing the frequency of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns, the voltage of the high-frequency power supplied from each of the drive units to each of the ultrasonic horns is adjusted based on the map.

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