JP2012112677A - Defect detection device and defect detection method - Google Patents

Abstract

A minute defect at an interface of a semiconductor device having a multi-layer structure is detected.
A defect detection apparatus 100 includes a light source (for example, coaxial illumination 3) that irradiates a semiconductor device 11 having a multi-layer structure with light 14, and an imaging unit (for example, a CCD camera 1) that images the semiconductor device 11. Have The defect detection device 100 further includes a defect determination unit 65 that detects at least a defect (for example, the resin peeling portion 9) in the interface 12 between the layers of the semiconductor device 11 based on the imaging result of the imaging unit. The light emitted from the light source is incident on the semiconductor device 11 from the surface (for example, the upper surface 13) facing the imaging unit in the semiconductor device 11 from the direction inclined with respect to the direction orthogonal to the interface 12. The reflected light 17 from the interface 12 is imaged.
[Selection] Figure 1

Description

  The present invention relates to a defect detection apparatus and a defect detection method.

  As an apparatus and method for detecting a defect in a semiconductor device having a multi-layer structure, for example, there is one described in Patent Document 1.

  In the technique of Patent Document 1, light is applied from the side surface of the sealing body to the sealing body in a state where the upper surface of the semiconductor device having the semiconductor chip and the transparent sealing body covering the semiconductor chip is opposed to the light detection unit. Is incident. When there is no defect in the sealing body, light from the semiconductor device does not enter the light detection unit, and when there is a defect in the sealing body, scattered light generated by the defect enters the light detection unit, The defect of the sealing body can be detected.

JP 2003-7746 A

  In the technique of Patent Document 1, for example, if the defect has a certain size in the height direction such as a foreign substance or a bubble, scattered light is likely to be generated, and the scattered light can be imaged with good contrast (brighter) by the light detection unit. Can be expected to detect as

  However, as a result of studies by the present inventors, it has been found that the technique of Patent Document 1 has the following problems. That is, in the technique of Patent Document 1, it is difficult to detect a very thin peeling defect at the interface between the sealing body and the semiconductor chip because the scattered light hardly occurs and the contrast is low (dark). In the technique of Patent Document 1, light is applied to the sealing body from an oblique direction at a low angle, and irregular reflection caused by a defect is detected as scattered light above the sealing body (using a so-called dark field optical system). Therefore, for very thin peeling, there are few areas that diffusely reflect and it is difficult to extract with good contrast.

  Thus, it has been difficult to detect minute defects at the interface of a semiconductor device having a multi-layer structure.

The present invention includes a light source for irradiating light to a semiconductor device having a multi-layer structure;
An imaging unit for imaging the semiconductor device;
Based on the imaging result by the imaging unit, at least a defect determination unit for determining a defect at an interface between layers of the semiconductor device;
Have
The light irradiated from the light source is incident on the semiconductor device from a direction inclined with respect to a direction orthogonal to the interface from a surface facing the imaging unit in the semiconductor device,
Provided is a defect detection apparatus characterized in that reflected light from the interface is imaged by the imaging unit.

  According to this defect detection apparatus, the light emitted from the light source is incident on the semiconductor device from the surface inclined to the direction orthogonal to the interface from the surface facing the imaging unit in the semiconductor device. Then, the reflected light from the interface is imaged by the imaging unit. Therefore, it is possible to detect a minute defect (such as a very thin peeling defect generated at the interface) at the interface of the semiconductor device having a multi-layer structure.

The present invention also includes a step of irradiating light to a semiconductor device having a multi-layer structure;
Imaging the semiconductor device with an imaging unit;
Determining a defect at an interface between layers of the semiconductor device based on a result of the imaging;
Have
In the step of irradiating the light, from the direction inclined with respect to the direction orthogonal to the interface, the light is incident on the semiconductor device from the surface facing the imaging unit in the semiconductor device,
Provided is a defect detection method characterized in that reflected light from the interface is imaged by the imaging unit.

  According to the present invention, it is possible to detect minute defects at the interface of a semiconductor device having a multi-layer structure.

It is a schematic diagram which shows the structure of the defect detection apparatus which concerns on 1st Embodiment. It is a typical sectional view showing a semiconductor device to be examined. In 1st Embodiment, it is a schematic diagram which shows the inclination of an optical axis in the state which adjusted the wedge prism to the predetermined | prescribed rotation angle with the rotation mechanism. It is a schematic diagram for demonstrating the defect detection method which concerns on 1st Embodiment. It is a schematic diagram which shows the structure of the defect detection apparatus which concerns on 2nd Embodiment. In 2nd Embodiment, it is a schematic diagram which shows the inclination of an optical axis in the state which adjusted the stage to the predetermined | prescribed rotation angle with the rotation mechanism. It is a schematic diagram for demonstrating the defect detection method which concerns on a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[First Embodiment]
FIG. 1 is a schematic diagram showing a configuration of a defect detection apparatus 100 according to the first embodiment.

  The defect detection apparatus 100 according to the present embodiment includes a light source (for example, coaxial illumination 3) that irradiates the semiconductor device 11 having a multi-layer structure with light 14, and an imaging unit (for example, the CCD camera 1) that images the semiconductor device 11. ) And a defect determination unit 65 that detects at least a defect (for example, the resin peeling portion 9 (FIG. 2)) at the interface 12 (FIG. 2) between the layers of the semiconductor device 11 based on the imaging result of the imaging unit. The light emitted from the light source is incident on the semiconductor device 11 from a surface (for example, the upper surface 13 (FIG. 2)) facing the imaging unit in the semiconductor device 11 from a direction inclined with respect to the direction orthogonal to the interface 12. The reflected light 17 (FIG. 4) from the interface 12 is picked up by the image pickup unit. Details will be described below.

  FIG. 2 is a schematic cross-sectional view showing the semiconductor device 11 to be inspected. Of these, FIG. 2A shows a case where no defect exists at the interface 12, and FIG. 2B shows a case where a defect (for example, the resin peeling portion 9) exists at the interface 12. The resin peeling portion 9 is a gap generated between the transparent sealing resin 8 and the semiconductor chip 7.

As shown in FIG. 2, the semiconductor device 11 has, for example, a flat base 18 (for example, a lead frame), a semiconductor chip (semiconductor element) 7 mounted on the base 18, and the semiconductor chip 7 sealed. And a transparent sealing resin 8. This light receiving device is used, for example, for an optical pickup of a CD (Compact Disc) device or a DVD (Digital Versatile Disc) device.
Such a light receiving device is generally configured by mounting a semiconductor chip 7 having a light receiving region on a lead frame, performing signal connection by wire bonding, and then sealing with a transparent sealing resin 8. .
In the case where there is a defect such as peeling (resin peeling portion 9), foreign matter or air bubbles at the interface 12 between the semiconductor chip 7 and the transparent sealing resin 8 (FIG. 2B), the light receiving sensitivity is decreased or the aging is deteriorated. May adversely affect quality.
As will be described below, such a defect can be detected by the defect detection apparatus 100 according to the present embodiment.

  As shown in FIG. 1, the defect detection apparatus 100 according to the present embodiment includes a CCD (Charge Coupled Device) camera 1, a lens 2, a coaxial illumination 3, a wedge prism 4, a rotation mechanism 5, and a control unit 6. And a stage 16.

The upper surface of the stage 16 is horizontally arranged, and the semiconductor device 11 is horizontally placed on the stage 16.
Here, the semiconductor chip 7 is mounted on the base material 18 so that the upper surface and the lower surface of the semiconductor chip 7 are parallel to the upper surface of the base material 18. Further, the transparent sealing resin 8 is formed so that the upper surface 13 is parallel to the upper surface of the semiconductor chip 7. As a result, the interface 12 and the upper surface 13 are parallel to the lower surface of the semiconductor device 11.
For this reason, the interface 12 and the upper surface 13 are horizontal in a state where the semiconductor device 11 is placed horizontally on the stage 16.

  The CCD camera 1 is disposed above the stage 16 and images the semiconductor device 11 on the stage 16 through the lens 2. The lens 2 is set to an observation magnification suitable for imaging for defect detection of the semiconductor device 11.

The coaxial illumination 3 irradiates the semiconductor device 11 on the stage 16 with light through the lens 2. The lens 2 constitutes an imaging unit together with the CCD camera 1 and constitutes a light source together with the coaxial illumination 3. The direction of the CCD camera 1 and the irradiation direction of the light 14 emitted from the light source are both vertically downward and coincide with each other. The coaxial illumination 3 is a coaxial epi-illumination and a bright field optical system.
In addition, the wavelength of the irradiation light from the coaxial illumination 3 can be appropriately selected according to, for example, the color of the surface of the semiconductor chip 7. When inspecting a general light receiving device, for example, white light or monochromatic light of 400 nm to 700 nm in the visible light region can be used.

The wedge prism 4 is positioned below the lens 2 and is disposed between the lens 2 and the semiconductor device 11 on the stage 16.
The wedge prism 4 has a characteristic of transmitting light incident on the wedge prism 4 with a declination. Specifically, the upper and lower surfaces of the wedge prism 4 are formed in a shape that is not parallel to each other (intersects each other).
For this reason, the optical axis of the light 15 transmitted through the wedge prism 4 and applied to the semiconductor device 11 is inclined with respect to the optical axis of the light 14 from the light source to the wedge prism 4. Therefore, the transparent sealing resin from the surface (that is, the upper surface 13) facing the CCD camera 1 in the semiconductor device 11 from the direction in which the light 15 is inclined with respect to the direction orthogonal to the interface 12 (vertical direction in the present embodiment). 8 can be made incident.
Thereby, a captured image equivalent to the case where the semiconductor device 11 or the CCD camera 1 is tilted can be obtained without tilting the semiconductor device 11 or the CCD camera 1.
In addition, the wedge prism 4 is arrange | positioned so that the upper surface may become horizontal, for example.
The amount of change of the optical axis by the wedge prism 4 is preferably, for example, 1 ° or more and 2 ° or less. By setting the change amount to 1 ° or more, that is, by setting the inclination of the optical axis of the light 15 with respect to the direction orthogonal to the interface 12 to 1 ° or more, when there is a defect in the interface 12, An image in which defects are emphasized can be acquired. Even if the defect is a minute defect such as a thin peeling defect, an image in which the defect is emphasized can be acquired. However, if the amount of change is too large, specularly reflected light from a portion that is not a defect is reduced, making it difficult to identify the defective portion. Therefore, the amount of change is preferably 2 ° or less.

The rotation mechanism 5 includes, for example, an actuator such as a motor and a drive transmission mechanism that transmits the power of the actuator to the wedge prism 4, and rotates the wedge prism 4 in a horizontal plane. This rotation is performed around the optical axis of the light 14 emitted from the light source.
By rotating the wedge prism 4 in this way, the inclination direction of the optical axis of the light 15 that passes through the wedge prism 4 and is irradiated on the semiconductor device 11 can be changed.
Thereby, a plurality of images equivalent to the case where the semiconductor device 11 is tilted in a plurality of predetermined directions can be obtained.

  FIG. 3 is a schematic diagram showing the inclination of the optical axis when the wedge prism 4 is adjusted to a predetermined rotation angle by the rotation mechanism 5. 3A shows a state adjusted to a first rotation angle (for example, 0 °), and FIG. 3B shows a state adjusted to a second rotation angle (for example, 180 °).

  As shown in FIG. 1, the control unit 6 controls the rotation of the wedge prism 4 by controlling the image input unit 61 that captures the image of the CCD camera 1, the illumination control unit 62 that switches the light quantity of the coaxial illumination 3, and the rotation mechanism 5. A rotation control unit 63 that adjusts the angle to a desired angle, a defect extraction unit 64 that extracts a defect portion from the image input to the image input unit 61, a defect determination unit 65 that determines the quality of the extracted defect, It is comprised including.

Next, the defect detection method according to this embodiment will be described.
This method includes at least a step of irradiating the semiconductor device 11 having a multi-layer structure with the light 15, a step of imaging the semiconductor device 11 with an imaging unit (for example, the CCD camera 1), and an imaging result, at least A step of determining defects (for example, the resin peeling portion 9) at the interface 12 between the layers of the semiconductor device 11, and in the step of irradiating the light 15, from the direction inclined with respect to the direction orthogonal to the interface 12, In the semiconductor device 11, light 15 is incident on the semiconductor device 11 from a surface facing the imaging unit (for example, the upper surface 13), and the reflected light 17 from the interface 12 is imaged by the imaging unit. Details will be described below.

FIG. 4 is a schematic diagram for explaining the defect detection method according to the present embodiment.
4A, 4 </ b> C, 4 </ b> E, and 4 </ b> G show the direction of the optical axis of the light 15 irradiated on the semiconductor device 11 and the direction of the reflected light 17 from the interface 12. FIG. 4A and 4C show a case where a defect (for example, the resin peeling portion 9) exists at the interface 12, and FIGS. 4E and 4G show a case where a defect does not exist at the interface 12. FIG. 4A and 4E show a state in which the wedge prism 4 is adjusted to the first rotation angle (0 °), and FIGS. 4C and 4G show the wedge prism 4 in the second rotation angle ( The state adjusted to 180 ° is shown.
FIGS. 4B, 4 </ b> D, 4 </ b> F, and 4 </ b> H are diagrams illustrating images (observation images) captured from above by the CCD camera 1. The observation image in the state of FIG. 4A is FIG. 4B, the observation image in the state of FIG. 4C is FIG. 4D, and the observation image in the state of FIG. Observation images in the state of (f) and FIG. 4 (g) are shown in FIG. 4 (h), respectively. Each observation image includes an image 80 of the transparent sealing resin 8 and an image 70 of the semiconductor chip 7.

On the other hand, FIG. 7 is a schematic diagram for explaining a defect detection method according to a comparative example.
In the defect detection method according to the comparative example, the light 15 is irradiated perpendicularly to the interface 12.
FIGS. 7A and 7C are diagrams showing the direction of the optical axis of the light 15 and the direction of the reflected light 17. FIG. 7A shows a case where a defect (resin peeling portion 9) exists at the interface 12, and FIG. 7C shows a case where a defect does not exist at the interface 12.
FIG. 7B is a diagram showing an observation image from above in the state of FIG. 7A, and FIG. 7D is a diagram showing an observation image from above in the state of FIG. 7C.

  The resin peeling portion 9 forms a pseudo concave lens between the semiconductor chip 7 and the transparent sealing resin 8. However, when the resin peeling part 9 is very thin, the curvature is very small. For this reason, when the semiconductor device 11 is not inclined with respect to the optical axis of the light 15 incident on the transparent sealing resin 8 as shown in FIG. When orthogonal, the light 15 is reflected at substantially the same angle as in the case of regular reflection and the reflected light 17 is formed, so that it is difficult to extract the resin peeling portion 9 as a defect. As shown in FIG. 7B, an image that can be distinguished from the surrounding portion does not appear in the range 92 corresponding to the resin peeling portion 9 in the observation image in this case. That is, the resin peeling portion 9 is not emphasized in this observation image, and it is difficult to distinguish the normal surface of the semiconductor chip 7 other than the resin peeling portion 9 from the resin peeling portion 9. This is because the reflected light 17 at the peripheral edge 9 of the resin peeling portion 9 is only slightly inclined with respect to the incident direction. Therefore, it is difficult to extract a defective part from the observation image.

  On the other hand, in this embodiment, the optical axis of the light 15 is inclined with respect to the direction orthogonal to the interface 12 as shown in FIG. To enter. For this reason, in a part of the peripheral part of the resin peeling part 9, the inclination of the reflected light 17 becomes large and the amount of light reflected immediately above becomes small. Therefore, as shown in FIG. 4B, a portion corresponding to a portion of the resin peeling portion 9 in the observation image becomes dark. That is, an image 91 that can be distinguished from the surrounding portion appears in a range 92 corresponding to the resin peeling portion 9 in the observation image of FIG. That is, the observation image of FIG. 4B includes an image 91 of a portion where the inclination of the reflected light 17 is particularly large in the resin peeling portion 9, and this image 91 is particularly darker (emphasized) than the surrounding image. Be visible). As a result, the defect extraction unit 64 can easily extract the portion of the image 91 as a defect.

In the present embodiment, even if the resin peeling portion 9 is a thin resin peeling defect, it can be recognized with good contrast on the observation image, so that the defect extraction processing by the defect extraction portion 64 is binarization processing or It can be performed by a general method such as a difference extraction process from a reference image registered in advance.
In addition, the defect determination unit 65 determines the quality of the image 91 of the defect portion extracted by the defect extraction unit 64. For example, when the dimension of the defective portion extracted as the image 91 is greater than or equal to a predetermined value, it is determined as a defective product, and when the size is less than the predetermined value, it is determined as a non-defective product.

Further, the position of the image 91 in the observation image changes depending on the direction in which the optical axis of the light 15 is inclined with respect to the direction orthogonal to the interface 12. For this reason, the wedge prism 4 is rotated by, for example, 0 °, 90 °, 180 °, and 270 ° by the rotation mechanism 5, observation images are acquired at the respective rotation angles, and defects are determined using these observation images. Thus, it is possible to perform the same determination as when the semiconductor device 11 is tilted (in the direction) at various angles, and the defect can be determined more accurately.
As an example, in the observation image when the wedge prism 4 is rotated 180 ° as shown in FIG. 4C, as shown in FIG. 4D, the image 91 is compared with the case of FIG. Is moved to the opposite side with the center of the resin peeling portion 9 as a reference.
By changing the rotation angle of the wedge prism 4 in this way, the pseudo tilt angle (direction) of the semiconductor device 11 can be changed, and defects can be extracted with a higher probability.

  In the case where there is no defect in the semiconductor device 11 (FIGS. 4E, 4G, and 7C), the observation image does not include an image indicating the defect of the semiconductor device 11 (FIG. 4 ( f), (h), FIG. 7 (d)).

  As described above, in this embodiment, the light 15 is incident by the coaxial epi-illumination, and the reflected light 17 other than the defective portion out of the reflected light 17 from the interface 12 becomes regular reflected light. The incident light to the camera 1 becomes brighter, and irregular reflection occurs at the defective portion, so that the regular reflection light is reduced and the incident light to the CCD camera 1 becomes darker. Then, by tilting the optical axis of the light 15 with respect to the direction orthogonal to the interface 12, the degree of irregular reflection can be increased and the peripheral portion of the thin resin peeling portion 9 can be captured with good contrast.

According to the first embodiment as described above, the surface (upper surface 13) facing the CCD camera 1 in the semiconductor device 11 from the direction in which the light 15 emitted from the light source is inclined with respect to the direction orthogonal to the interface 12. To the transparent sealing resin 8. Then, the reflected light 17 from the interface 12 is imaged by the CCD camera 1. Therefore, a minute defect (for example, a very thin peeling defect) at the interface 12 can be detected with high sensitivity. It should be noted that not only peeling defects but also defects such as bubbles and foreign substances existing at the interface 12 can be detected in the same manner.
Furthermore, not only the defect which generate | occur | produces in the interface 12, but the defect which exists in the inside of the transparent sealing resin 8 between the interface 12 and the upper surface 13 can be detected similarly.

  Further, by using the wedge prism 4, for example, a fine angle adjustment of 1 ° or more and 2 ° or less can be accurately performed as compared with the case where the light source, the imaging unit, or the stage 16 is moved. This is because the inclination angle of the optical axis of the light 15 with respect to the direction orthogonal to the interface 12 is 1 ° or more and 2 ° or less while the wedge prism 4 is fixed or the angle of the wedge prism 4 is adjusted only in the horizontal plane. This is because imaging can be performed by setting the desired angle. Since the deflection angle of the wedge prism 4 is a value inherent to the wedge prism 4, rotating the wedge prism 4 as described above maintains the constant amount of inclination of the optical axis of the light 15, This is nothing but changing only the tilt direction of the optical axis. That is, as long as the wedge prism 4 is not tilted (unless moved in the so-called tilt direction), the tilt amount of the optical axis of the light 15 can be kept constant.

Further, since the direction of the CCD camera 1 and the irradiation direction of the light 15 coincide with each other and the wedge prism 4 that tilts the optical axis of the light 15 is provided at a position between the lens 2 and the semiconductor device 11, the semiconductor device 11. Even if the semiconductor device 11 is not inclined, an observation image similar to that obtained when the semiconductor device 11 is inclined can be obtained.
Here, a plurality of products such as light receiving devices are formed on a single lead frame. In many cases, the defect detection apparatus 100 is configured to inspect the lead frame by sequentially feeding the lead frame one pitch at a time (one product pitch). For this reason, there is a merit that rotating the wedge prism 4 side is mechanically simpler than a mechanism for rotating or tilting the product side.

  In addition, since the rotation mechanism 5 is provided as a moving unit that moves the wedge prism 4 so that the inclination of the optical axis of the light 15 changes, the semiconductor device 11 is irradiated with the light 15 from a plurality of angles. By performing the inspection with the above, it is possible to extract a defect with higher sensitivity.

[Second Embodiment]
In the first embodiment, the example in which the optical axis of the light 15 is tilted using the wedge prism 4 has been described. However, in the second embodiment, instead of using the wedge prism 4, the angle of the stage 16 is changed. By changing, the optical axis of the light 15 is inclined with respect to the direction orthogonal to the interface 12. In the present embodiment, the light emitted from the lens 2 (the light 14 in the first embodiment) and the light incident on the semiconductor device 11 (the light 15 in the first embodiment) Are not distinguished from each other because the optical axes are the same, and both are referred to as light 15.

  FIG. 5 is a schematic diagram showing the configuration of the defect detection apparatus according to the second embodiment, and FIG. 6 shows the light 15 in a state in which the stage 16 is adjusted to a predetermined rotation angle by the rotation mechanism 5 in the second embodiment. It is a schematic diagram which shows the inclination of an axis | shaft.

  In the present embodiment, the defect detection apparatus 100 does not have the wedge prism 4. The stage 16 is inclined with respect to a horizontal plane (for example, 1 ° or more and 2 ° or less). Thereby, the optical axis of the light 15 is inclined with respect to the direction orthogonal to the interface 12.

  In the present embodiment, the rotation mechanism 5 rotates the stage 16, not the wedge prism 4, around the vertical axis. This rotation is performed while maintaining the tilt of the stage 16. FIG. 6A shows a state where the stage 16 is rotated so that the stage 16 is inclined to the right shoulder, and FIG. 6B shows a state where the stage 16 is inclined to the left shoulder. A state in which the stage 16 is rotated is shown.

  Thus, also in this embodiment, the positional relationship between the direction of the optical axis of the light 15 and the interface 12 can be made the same as in the first embodiment, and the orientation of the CCD camera 1 and the interface 12 The relationship with the optical axis of the reflected light 17 (see FIG. 4) can be made substantially the same as in the first embodiment. Therefore, also in the second embodiment, the same effect as in the first embodiment can be obtained in terms of defect detection.

  In the second embodiment, the example in which the optical axis of the light 15 is inclined with respect to the direction orthogonal to the interface 12 by inclining the stage 16 has been described. For example, the direction of the CCD camera 1 is changed from the lens 2. Even if it is inclined with respect to the optical axis of the emitted light, the same effect as in the second embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 CCD camera 2 Lens 3 Coaxial illumination 4 Wedge prism 5 Rotation mechanism 6 Control part 7 Semiconductor chip 8 Transparent sealing resin 9 Resin peeling part 11 Semiconductor device 12 Interface 13 Upper surface 14, 15 Light 16 Stage 17 Reflected light 18 Base material 61 Image Input unit 62 Illumination control unit 63 Rotation control unit 64 Defect extraction unit 65 Defect determination unit 70 Image 80 of semiconductor chip in observation image from above Image 91 of transparent sealing resin in observation image from above Image 92 of part of resin peeling portion emphasized in observation image Range 100 corresponding to resin peeling portion in observation image from above 100 Defect detection device

Claims (8)

A light source for irradiating light to a semiconductor device having a multi-layer structure;
An imaging unit for imaging the semiconductor device;
Based on the imaging result by the imaging unit, at least a defect determination unit for determining a defect at an interface between layers of the semiconductor device;
Have
The light irradiated from the light source is incident on the semiconductor device from a direction inclined with respect to a direction orthogonal to the interface from a surface facing the imaging unit in the semiconductor device,
A defect detection apparatus, wherein the imaging unit images reflected light from the interface. The direction of the imaging unit and the irradiation direction of light from the light source match,
The defect detection apparatus according to claim 1, further comprising a wedge prism that tilts an optical axis of light emitted from the light source at a position between the light source and the semiconductor device.   The defect detection apparatus according to claim 2, further comprising a moving unit that moves the wedge prism so that the inclination of the optical axis changes.   The defect detection apparatus according to any one of claims 1 to 3, wherein the inclination angle is not less than 1 ° and not more than 2 °. The semiconductor device has a semiconductor chip and a transparent sealing resin that seals the semiconductor chip,
The defect detection apparatus according to claim 1, wherein the interface is an interface between the transparent sealing resin and the semiconductor chip. Irradiating a semiconductor device having a multi-layer structure with light;
Imaging the semiconductor device with an imaging unit;
Determining a defect at an interface between layers of the semiconductor device based on a result of the imaging;
Have
In the step of irradiating the light, from the direction inclined with respect to the direction orthogonal to the interface, the light is incident on the semiconductor device from the surface facing the imaging unit in the semiconductor device,
A defect detection method, wherein the imaging unit images reflected light from the interface. Match the direction of the imaging unit and the direction of light irradiation from the light source,
The light is transmitted to a wedge prism disposed at a position between the light source and the semiconductor device so that the optical axis of the light is inclined to irradiate the semiconductor device with the light. 6. The defect detection method according to 6.   The defect detection method according to claim 7, further comprising adjusting the direction of the optical axis by moving the wedge prism so that the inclination of the optical axis changes.

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