Inspection apparatus and inspection method

Abstract

To precisely discriminate a smear in a via hole from foreign matter other than the smear.SOLUTION: An inspection device 1 for inspecting a via hole of a board 9 has a light irradiation part 31 and a spectrometry part 33. The light irradiation part 31 applies excitation light for generating fluorescence in resin for forming an insulation layer to an area to be inspected including a via hole on a multilayer board (namely, the board 9) in which a wiring layer and an insulation layer are laminated alternately. The spectrometry part 33 acquires reflection spectra by receiving reflection light from the area to be inspected. Accordingly, smear in the via hole can be precisely discriminated from foreign matter other than the smear.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for inspecting via holes in a substrate.

Background Art

[0002] Conventionally, in the manufacture of a multilayer substrate in which wiring layers and insulating layers are alternately laminated, laser via processing has been performed. In laser via processing, in a multilayer substrate during manufacture, by irradiating a part of the wiring layer that is the uppermost layer with laser light, the wiring layer and the insulating layer below the wiring layer are penetrated, and a via hole (also called a via hole or a via) having the wiring layer below the insulating layer as the bottom is formed. On the inner surface of the via hole, copper (Cu) or the like is plated by subsequent processing, and an electrical connection (that is, a conductive state) between the upper and lower wiring layers is ensured.

[0003] In such laser via processing, residues (that is, smears) of the resin forming the insulating layer may remain on the bottom surface of the via hole. The smear becomes a factor in reducing the reliability of the electrical connection between the wiring layers. Therefore, an inspection device is used in which excitation light is irradiated onto a large number of via holes formed in a multilayer substrate, and the fluorescence generated by the smear is received by a photodiode or the like to inspect the presence or absence of the smear in the via hole. When a smear is detected by the inspection device, a desmearing process is performed to remove the smear.

[0004] Also, in Patent Document 1, a technique has been proposed for confirming the presence or absence of resin (that is, the material of the insulating layer) in a via hole during formation by laser via processing in parallel with the processing of the via hole. Specifically, excitation light is emitted toward the via hole during formation in parallel with the processing of the via hole, and the fluorescence generated by the resin forming the insulating layer is received by a photodiode to confirm the presence or absence of the resin (that is, the material of the insulating layer) in the via hole. Then, as the formation of the via hole progresses and the intensity of the fluorescence from the via hole decreases below a threshold value, it is determined that the resin in the via hole has been sufficiently removed (that is, there is no smear).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, there may be foreign matter other than smears in the via hole, and in order to remove foreign matter other than smears, a removal process different from the desmear process is required. However, such foreign matter may also generate fluorescence when irradiated with excitation light. In this case, it is difficult for the above-described inspection apparatus to distinguish between smears and foreign matter other than smears.

[0007] Currently, an operator visually inspects the via hole with a fluorescence microscope or the like to determine whether the foreign matter in the via hole is a smear or not. However, the discrimination work requires a relatively long time, and there is a possibility that the determination may vary depending on the skill level of the operator.

[0008] The present invention has been made in view of the above problems, and an object thereof is to accurately discriminate between smears and foreign matter other than smears in a via hole.

Means for Solving the Problems

[0009] The invention according to claim 1 is an inspection apparatus for inspecting a via hole of a substrate, wherein excitation light that generates fluorescence is irradiated onto a resin that forms the insulating layer with respect to an inspection region including the via hole on a laminated substrate in which a wiring layer and an insulating layer are alternately laminated. excitation Light Output unit, a white light emitting unit that emits white light to the inspection area; From the inspection region Light Receives Record And shows the light quantity distribution for each wavelength of Susu A spectroscopic measurement unit that acquires a spectrum, an imaging unit that receives light from the inspection area and obtains an inspection image that is an image of the inspection area; Comprising.

[0010] The invention according to claim 2 is The method according to claim 1 an inspection apparatus ,before further comprising a filter unit disposed on an optical path from the inspection region to the spectroscopic measurement unit for guiding light in a wavelength range different from the excitation light to the spectroscopic measurement unit.

[0011] The invention according to claim 3 is The method according to claim 1 or 2 an inspection apparatus ,before comprising a display for displaying the inspection image obtained by the imaging unit and the spectrum obtained by the spectroscopic measurement unit. Note Further

[0012] The invention according to claim 4 is the inspection apparatus according to claim Any one of 1 to 3 further comprising a pinhole mirror disposed on an optical path from the inspection region to the spectroscopic measurement unit, wherein the spectroscopic measurement unit receives light that has passed through the pinhole of the pinhole mirror, and the imaging unit receives light that has been reflected by the pinhole mirror from the inspection region. Light Light

[0014] The invention according to claim 5 is the inspection apparatus according to claim Any one of 1 to 4 wherein ,before the excitation light from the excitation light emitting unit and the white light from the white light emitting unit can be simultaneously irradiated onto the inspection region. teeth

[0015] The invention according to claim 6 is The method according to any one of claims 1 to 5. an inspection apparatus ,before comprising a wavelength switching unit for switching the wavelength of the excitation light among a plurality of wavelengths. moreover

[0016] The invention according to claim 7 ​​​​​​The invention described in [reference] is an inspection method for inspecting via holes in a substrate, comprising: a) irradiating an excitation light that generates fluorescence in the resin forming the insulating layer onto a region to be inspected including via holes on a laminated substrate in which wiring layers and insulating layers are alternately laminated; b) emitting white light to the inspection area; and c) ) receiving [light] from the region to be inspected Light and obtaining a Record spectrum showing the light quantity distribution for each wavelength of the [light] Susu ; and d) receiving light from the inspection area to obtain an inspection image which is an image of the inspection area; and e) ) inspecting the via holes based on the Note spectrum and the inspection image .

Advantages of the Invention

[0017] In the present invention, it is possible to accurately discriminate between smears in the via holes and foreign matter other than smears.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing the configuration of an inspection apparatus according to the first embodiment. [Diagram 2] It is a diagram showing the configuration of a computer that realizes a control unit. [Diagram 3] It is a block diagram showing the functions of the control unit. [Figure 4] It is a cross-sectional view of a substrate. [Figure 5A] It is a diagram showing an inspected image when excitation light is irradiated. [Figure 5B] It is a diagram showing a reflection spectrum when excitation light is irradiated. [Figure 6A] It is a diagram showing an inspected image when white light is irradiated. [Figure 6B] It is a diagram showing a reflection spectrum when white light is irradiated. [Figure 7A] It is a diagram showing an inspected image when excitation light and white light are irradiated. [Figure 7B] It is a diagram showing a reflection spectrum when excitation light and white light are irradiated. [Figure 8A] It is a diagram showing an inspected image when white light is irradiated. [Figure 8B] It is a diagram showing an inspection image when excitation light is irradiated. [Figure 9] It is a diagram showing the flow of via hole inspection. [Figure 10] It is a cross-sectional view of a substrate. [Figure 11A] It is a diagram showing an inspection image when excitation light is irradiated. [Figure 11B] It is a diagram showing a reflection spectrum when excitation light is irradiated. [Figure 12A] It is a diagram showing an inspection image when white light is irradiated. [Figure 12B] It is a diagram showing a reflection spectrum when white light is irradiated. [Figure 13A] It is a diagram showing an inspection image when excitation light and white light are irradiated. [Figure 13B] It is a diagram showing a reflection spectrum when excitation light and white light are irradiated. [Figure 14] It is a cross-sectional view of a substrate. [Figure 15] It is a cross-sectional view of a substrate. [Figure 16] It is a diagram showing the configuration of another inspection apparatus. [Figure 17] It is a diagram showing the configuration of an inspection apparatus according to a second embodiment. [Figure 18] It is a diagram showing the configuration of an inspection apparatus according to a third embodiment. [Figure 19] It is a diagram showing the configuration of an inspection apparatus according to a fourth embodiment.

Embodiments for Carrying Out the Invention

[0019] FIG. 1 is a diagram showing the configuration of an inspection apparatus 1 according to a first embodiment of the present invention. The inspection apparatus 1 is an apparatus for inspecting via holes (also called via holes or vias) provided in a laminated substrate 9. The laminated substrate 9 is, for example, a multilayer substrate in which wiring layers and insulating layers are alternately laminated on a plate-shaped or sheet-shaped base material formed of resin. The wiring layer is a wiring pattern formed of a conductive material such as copper. The insulating layer is formed of a resin such as polyimide and insulates adjacent wiring layers in the lamination direction. In the following description, the laminated substrate 9 is also simply referred to as "substrate 9".

[0020] A large number of via holes are formed on the upper surface 91 of the substrate 9. The via hole is a hole that penetrates the uppermost wiring layer and the insulating layer adjacent to the lower side of the wiring layer and has the wiring layer adjacent to the lower side of the insulating layer as the bottom. Foreign matter may exist on the bottom surface of the via hole. The foreign matter is, for example, smear (that is, residue of the resin forming the insulating layer) generated during the processing of the via hole. There may also be foreign matter other than smears (for example, a resin different from the resin forming the insulating layer) on the bottom surface of the via hole.

[0021] The inspection apparatus 1 is an apparatus for inspecting foreign matter when foreign matter exists in a via hole provided on the upper surface 91 of the substrate 9. The inspection apparatus 1 inspects, for example, via holes in which foreign matter has been detected by an appearance inspection apparatus or the like among a large number of via holes on the substrate 9 and is used to determine whether the foreign matter is a smear or foreign matter other than a smear.

[0022] The inspection apparatus 1 includes a stage 21, a stage moving mechanism 22, a head 3, a head moving mechanism 23, and a control unit 4. The control unit 4 controls each component of the inspection apparatus 1. In FIGS. 16 to 19 described later, the illustration of the control unit 4 is omitted.

[0023] The stage 21 is disposed below the head 3 and holds the horizontally placed substrate 9 from below. The stage 21 is, for example, a vacuum chuck that sucks and holds the lower surface of the substrate 9 or a mechanical chuck that mechanically limits the horizontal movement of the substrate 9.

[0024] The stage moving mechanism 22 is a moving mechanism that relatively moves the stage 21 horizontally with respect to the head 3 (i.e., in a direction substantially parallel to the upper surface 91 of the substrate 9). In the example shown in FIG. 1, the stage moving mechanism 22 linearly moves the stage 21 in the left-right direction in the figure. The drive source of the stage moving mechanism 22 is, for example, a linear servo motor or a ball screw with a motor attached thereto. The structure of the stage moving mechanism 22 may be variously changed.

[0025] When inspecting the via holes of the substrate 9 on the stage 21, the head 3 irradiates light on the substrate 9 and receives the reflected light from the substrate 9. Details of the structure of the head 3 will be described later. The head moving mechanism 23 is a moving mechanism that relatively moves the head 3 horizontally with respect to the stage 21. In the example shown in FIG. 1, the head moving mechanism 23 linearly moves the head 3 in a direction perpendicular to the paper surface (i.e., in a direction substantially parallel to the upper surface 91 of the substrate 9 and perpendicular to the moving direction by the stage moving mechanism 22). The drive source of the head moving mechanism 23 is, for example, a linear servo motor or a ball screw with a motor attached thereto. The structure of the head moving mechanism 23 may be variously changed.

[0026] The head 3 includes a light irradiation unit 31, a detection optical system 32, a spectroscopic measurement unit 33, and an imaging unit 34. The light irradiation unit 31, the detection optical system 32, the spectroscopic measurement unit 33, and the imaging unit 34 are housed inside the head housing 35. In FIG. 1, the head housing 35 is drawn with a dashed line, and the internal configuration of the head housing 35 is drawn with a solid line.

[0027] The light irradiation unit 31 irradiates light onto the inspection region including the via holes on the substrate 9. The light irradiation unit 31 includes an excitation light emitting unit 311 and a white light emitting unit 312. The excitation light emitting unit 311 emits excitation light toward the inspection region of the substrate 9. The excitation light is light having a wavelength that causes the resin forming the insulating layer of the substrate 9 to generate fluorescence. As the excitation light emitting unit 311, for example, an LED (Light Emitting Diode) can be used. For example, excitation light with a wavelength of 405 nm is emitted from the excitation light emitting unit 311, and fluorescence in a wavelength range with a peak of 430 nm is generated from the resin forming the insulating layer. Note that depending on the type of resin, the wavelength range of the fluorescence and the wavelength of the excitation light that generates the fluorescence vary variously. Also, in the wiring layer of the substrate 9, fluorescence is not generated by the irradiation of the excitation light. When there are foreign substances on the substrate 9, when the foreign substances are irradiated with the excitation light, depending on the type of the foreign substances, fluorescence may or may not be generated. When the foreign substances generate fluorescence, the wavelength range of the fluorescence is different from the wavelength range of the fluorescence generated by the insulating layer.

[0028] The white light emitting unit 312 emits white light (that is, light with a broadband wavelength) toward the inspection region of the substrate 9. As the white light emitting unit 312, for example, an LED can be used. In the inspection apparatus 1, light can be emitted from only one of the excitation light emitting unit 311 and the white light emitting unit 312, and light can also be emitted from both simultaneously. In FIG. 1, the optical axes of the light emitted from the excitation light emitting unit 311 and the white light emitting unit 312 are indicated by dashed-dotted lines.

[0029] The detection optical system 32 includes a first collimator lens 321, a second collimator lens 322, a dichroic mirror 323, a half mirror 324, an objective lens 325, a condenser lens 326, a pinhole mirror 327, and an imaging lens 328.

[0030] The excitation light emitted from the excitation light emitting unit 311 is guided to the dichroic mirror 323 via the first collimator lens 321. The dichroic mirror 323 reflects the excitation light and transmits light in a wavelength range different from that of the excitation light. The excitation light reflected by the dichroic mirror 323 passes through the half mirror 324 and is guided to the upper surface 91 of the substrate 9 via the objective lens 325. The excitation light is approximately focused on the upper surface 91 of the substrate 9 and irradiates the inspection area. Also, the white light emitted from the white light emitting unit 312 is guided to the half mirror 324 via the second collimator lens 322. The white light is reflected by the half mirror 324 and is guided to the upper surface 91 of the substrate 9 via the objective lens 325. The white light is approximately focused on the upper surface 91 of the substrate 9 and irradiates the inspection area.

[0031] The light reflected in the inspection area (i.e., the reflected light from the inspection area) passes through the objective lens 325 and the half mirror 324 and is guided to the dichroic mirror 323. The dichroic mirror 323 is disposed on the optical path of the reflected light from the inspection area on the substrate 9 toward the spectroscopic measurement unit 33. The dichroic mirror 323 reflects the excitation light among the reflected light from the inspection area and transmits light in a wavelength range different from that of the excitation light. The dichroic mirror 323 is a filter unit that separates light in a wavelength range different from that of the excitation light from the excitation light and guides it to the spectroscopic measurement unit 33. The light transmitted through the dichroic mirror 323 (i.e., light in a wavelength range different from that of the excitation light) is guided to the pinhole mirror 327 via the condenser lens 326. The pinhole mirror 327 is disposed on the optical path of the reflected light from the inspection area toward the spectroscopic measurement unit 33 and is optically approximately conjugate with the upper surface 91 of the substrate 9.

[0032] The light that has passed through the pinhole 327a of the pinhole mirror 327 is guided to the spectroscopic measurement unit 33 and received by the spectroscopic measurement unit 33. The spectroscopic measurement unit 33 acquires the spectrum of the received light (i.e., the light in a wavelength range different from the excitation light among the reflected light from the inspection area). In the following description, the spectrum acquired by the spectroscopic measurement unit 33 (i.e., the spectrum of the reflected light from the inspection area) is also referred to as the "reflection spectrum". The reflection spectrum acquired by the spectroscopic measurement unit 33 is sent to the control unit 4.

[0033] The spectroscopic measurement unit 33 includes, for example, a grating (i.e., a diffraction grating) 331 and a spectroscopic analysis unit 332. The grating 331 is an optical element that disperses (i.e., spectroscopically analyzes) the light incident on the spectroscopic measurement unit 33 into lights of various wavelengths. The spectroscopic analysis unit 332 includes a plurality of light-receiving elements that respectively receive the lights of a plurality of wavelengths spectroscopically analyzed by the grating 331. As the light-receiving element, for example, a line sensor or an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Devices) can be used. Note that in the spectroscopic measurement unit 33, other spectrometers such as a prism may be used instead of the grating 331.

[0034] The light reflected by the above-described pinhole mirror 327 is guided to the imaging unit 34 through the imaging lens 328. The imaging unit 34 receives the light that has passed through the dichroic mirror 323 and is reflected by the pinhole mirror 327 among the reflected light from the inspection area, and acquires an inspection image that is an image of the inspection area. As described above, since the pinhole mirror 327 is approximately conjugate with the upper surface 91 of the substrate 9, the pinhole 327a of the pinhole mirror 327 appears as a black dot on the inspection image. The inspection image acquired by the imaging unit 34 is sent to the control unit 4. As the imaging unit 34, for example, an image sensor such as a CMOS or a CCD can be used.

[0035] In the example shown in FIG. 1, the optical axis of the light irradiated onto the inspection area of the substrate 9 through the objective lens 325 is perpendicular to the upper surface 91 of the substrate 9, and the optical axis of the reflected light incident on the objective lens 325 from the inspection area coincides with the optical axis. That is, in the head 3, coaxial epi-illumination is realized. Note that the configuration of the detection optical system 32 in the head 3 may be changed as appropriate. Further, the configurations of the excitation light emitting unit 311, the white light emitting unit 312, the spectroscopic measurement unit 33, the imaging unit 34, and the like may also be changed as appropriate.

[0036] FIG. 2 is a diagram showing the configuration of a computer 100 that realizes the control unit 4. The computer 100 is a normal computer including a processor 101, a memory 102, an input / output unit 103, and a bus 104. The bus 104 is a signal circuit that connects the processor 101, the memory 102, and the input / output unit 103. The memory 102 stores programs and various information. The processor 101 executes various processes (for example, numerical calculations and image processing) while using the memory 102 and the like according to programs and the like stored in the memory 102. The input / output unit 103 includes a keyboard 105 and a mouse 106 that receive inputs from an operator, and a display 107 that displays outputs from the processor 101 and the like. Note that the control unit 4 may be a programmable logic controller (PLC), a circuit board, or the like, or a combination of these and one or more computers.

[0037] FIG. 3 is a block diagram showing the functions of the control unit 4 realized by the computer 100. In FIG. 3, the configurations other than the control unit 4 are also shown. The control unit 4 includes a storage unit 41, a movement control unit 42, and a display control unit 43. The storage unit 41 is mainly realized by the memory 102 and stores various information related to the inspection of via holes. In the storage unit 41, for example, the position information of the via holes that need to be inspected by the inspection device 1 among a large number of via holes on the substrate 9 is stored. The position information is input, for example, by an operator or the like via the input / output unit 103. Alternatively, the position information is sent from an appearance inspection device or the like that has acquired the position information to the control unit 4. Also, in the storage unit 41, the reflection spectrum sent from the spectroscopic measurement unit 33 to the control unit 4 and the inspection target image sent from the imaging unit 34 to the control unit 4 as described above are also stored.

[0038] The movement control unit 42 is mainly realized by the processor 101. Based on the above-described position information of the via holes stored in the storage unit 41, the movement control unit 42 drives the stage movement mechanism 22 and the head movement mechanism 23 to move the irradiation position of the light from the head 3 onto the inspection target area including the via holes. The display control unit 43 is mainly realized by the processor 101. The display control unit 43 controls the display 107 or the like, which is a display unit, to display the above-described reflection spectrum and inspection target image stored in the storage unit 41 on the display 107.

[0039] FIG. 4 is a cross-sectional view of the substrate 9 showing the via hole 93. In the example shown in FIG. 4, there are no foreign substances such as smears in the via hole 93, and the via hole 93 is not actually an inspection target of the inspection apparatus 1. However, hereinafter, a case where the via hole 93 is inspected by the inspection apparatus 1 will be described. In the example shown in FIG. 4, an opening 941 that includes the via hole 93 and is larger than the via hole 93 is formed in the uppermost wiring layer 94a, and the insulating layer 95 around the via hole 93 is exposed from the opening 941. Also, at the bottom surface 931 of the via hole 93, the upper surface of the second wiring layer 94b is exposed. Note that in FIG. 4, the bottom surface 931 of the via hole 93 is drawn as a plane, but it may have other shapes (for example, a concave shape in which the center is recessed more than the peripheral portion).

[0040] FIGS. 5A and 5B are diagrams showing an inspection image acquired by the imaging unit 34 and a reflection spectrum acquired by the spectroscopic measurement unit 33 when the excitation light is irradiated from the excitation light emitting unit 311 shown in FIG. 1 to the inspection region including the via hole 93 in the inspection apparatus 1. The inspection image shown in FIG. 5A is acquired in a state where the pinhole 327a of the above-described pinhole mirror 327 is aligned so as to be located on the bottom surface 931 of the via hole 93. The same applies to other inspection images described later.

[0041] The excitation light reflected by the second wiring layer 94b, which is the bottom surface 931 of the via hole 93, is reflected by the dichroic mirror 323 and does not enter the spectroscopic measurement unit 33 and the imaging unit 34. Therefore, in the inspection image shown in FIG. 5A, the bottom surface 931 of the via hole 93 appears as a substantially circular black region. Note that in an actual inspection image, the pinhole 327a of the pinhole mirror 327 is included as a black dot in the bottom surface 931 of the via hole 93, but in FIG. 5A, the pinhole 327a is shown as a white dot for easy understanding of the figure.

[0042] Only the light from the region corresponding to the pinhole 327a enters the spectroscopic measurement unit 33. In the example shown in FIG. 5A, the light from the pinhole 327a is excitation light and is reflected by the dichroic mirror 323 as described above and does not enter the spectroscopic measurement unit 33. Therefore, the reflection spectrum shown in FIG. 5B shows substantially 0 at each wavelength. Naturally, in the said reflection spectrum, there is no peak corresponding to the excitation light (i.e., the peak at the position of wavelength 405 nm).

[0043] The insulating layer 95 around the via hole 93 generates fluorescence when irradiated with excitation light. The said fluorescence passes through the dichroic mirror 323 and enters the imaging unit 34. For this reason, in the inspection image, the insulating layer 95 appears as a substantially annular blue region. Note that only the light from the region corresponding to the pinhole 327a of the pinhole mirror 327 enters the spectroscopic measurement unit 33 as described above, so the said fluorescence does not enter. Therefore, in the reflection spectrum shown in FIG. 5B, there is no peak corresponding to the fluorescence (i.e., the peak at the position of wavelength 430 nm).

[0044] The excitation light reflected by the wiring layer 94a around the aperture 941 is reflected by the dichroic mirror 323 and does not enter the spectroscopic measurement unit 33 and the imaging unit 34. For this reason, in the inspection image shown in FIG. 5A, the wiring layer 94a appears as a black region around the insulating layer 95.

[0045] Figures 6A and 6B are diagrams showing a test image and a reflection spectrum when white light is irradiated from the white light emitting unit 312 onto the test area in the inspection apparatus 1, respectively. In the test image shown in FIG. 6A, the wiring layer 94b on the bottom surface 931 of the via hole 93 and the wiring layer 94a around the insulating layer 95 appear in a color close to red because they are made of copper. Note that since the white light reaches the wiring layer 94b on the bottom surface 931 of the via hole 93 less easily than the uppermost wiring layer 94a, it appears in a darker red color than the wiring layer 94a in the test image. Also, the insulating layer 95 appears in a color close to dark gray, darker than the wiring layers 94a and 94b. The white light reflected by the wiring layer 94b on the bottom surface 931 of the via hole 93 (however, excluding light having the same wavelength as the excitation light) passes through the pinhole 327a of the pinhole mirror 327 and enters the spectroscopic measurement unit 33. Therefore, the reflection spectrum shown in FIG. 5B shows substantially the same spectrum as the reflection spectrum of white light by copper.

[0046] Figures 7A and 7B are diagrams showing a test image and a reflection spectrum when excitation light and white light are simultaneously irradiated onto the test area in the inspection apparatus 1, respectively. In the test image shown in FIG. 7A, the wiring layer 94b on the bottom surface 931 of the via hole 93 and the wiring layer 94a around the insulating layer 95 appear in a color close to red as described above. Since the insulating layer 95 generates fluorescence, it appears in a color close to bright white, brighter than the wiring layers 94a and 94b. Also, since the fluorescence from the insulating layer 95 is also irradiated inside the via hole 93, in the test image shown in FIG. 7A, the wiring layer 94b on the bottom surface 931 of the via hole 93 appears in a brighter red color than the test image shown in FIG. 6A (i.e., the test image captured only with white light). Therefore, the bottom surface 931 of the via hole 93 can be clearly observed. Also, in the test image shown in FIG. 7A, the boundary between the bottom surface 931 of the via hole 93 and the insulating layer 95 is also clearer than the test image shown in FIG. 6A. Therefore, by simultaneously irradiating the test area with excitation light and white light, the observation of the bottom surface 931 of the via hole 93 becomes easier compared to the case where only white light is irradiated.

[0047] In the example shown in FIG. 7A, among the white light and the excitation light reflected by the wiring layer 94b on the bottom surface 931 of the via hole 93, the white light (however, excluding the light having the same wavelength as the excitation light) passes through the dichroic mirror 323 and the pinhole 327a and enters the spectroscopic measurement unit 33, while the excitation light is reflected by the dichroic mirror 323 and does not enter the spectroscopic measurement unit 33. Therefore, the reflection spectrum shown in FIG. 7B shows almost the same spectrum as the reflection spectrum of the white light by copper.

[0048] In the inspection of the substrate 9 using the inspection apparatus 1, the operator checks the inspection images and the reflection spectra shown in FIGS. 5A, 5B, FIGS. 6A, 6B, and FIGS. 7A, 7B, and determines that there is no foreign matter in the via hole 93. Specifically, for example, in the reflection spectra shown in FIGS. 5B and 7B, by confirming that there is no peak corresponding to the fluorescence generated by the insulating layer 95 (that is, the peak at the position of a wavelength of 430 nm), it is determined that there is no smear on the bottom surface 931 of the via hole 93. Further, by confirming that the reflection spectra shown in FIGS. 6B and 7B approximately match the reference spectrum acquired in advance (that is, the reflection spectrum of the white light by copper), it is determined that there is no foreign matter other than the smear on the bottom surface 931 of the via hole 93. Furthermore, in the inspection images shown in FIGS. 5A, 6A, and 7A, it is visually confirmed that there is no foreign matter in the via hole 93. Note that the method for determining the presence or absence of foreign matter using the inspection images and the reflection spectra may be variously changed.

[0049] In the inspection apparatus 1, when only white light is irradiated, in order to make the bottom surface 931 of the via hole 93 observable in the inspection image, for example, the depth of the via hole 93 (that is, the vertical distance from the upper end opening of the via hole 93 to the bottom surface 931) is preferably 2 / 3 or less of the diameter of the upper end opening of the via hole 93. On the other hand, when the excitation light is irradiated, as described above, the fluorescence from the insulating layer 95 is irradiated into the via hole 93, so that the bottom surface 931 of the via hole 93 becomes bright in the inspection image. Therefore, even for a via hole 93 whose depth is larger than 2 / 3 of the diameter of the upper end opening, the bottom surface 931 can be observed.

[0050] FIG. 8A is an inspection image of the bottom surface 931 of the via hole 93 taken by irradiating only white light for a via hole 93 having a relatively large depth (that is, a high aspect ratio) with respect to the diameter of the upper end opening. FIG. 8B is an inspection image of the bottom surface 931 of the via hole 93 taken by irradiating the excitation light for the via hole 93. In FIG. 8A, almost no light reaches the bottom surface 931 of the via hole 93 and the position of the bottom surface 931 is only vaguely known, whereas in FIG. 8B, the bottom surface 931 of the via hole 93 can be observed relatively clearly.

[0051] Next, with reference to FIG. 9, the flow of the inspection of the via hole using the inspection apparatus 1 will be described. First, based on the position information of the via hole to be inspected (that is, the via hole in which some abnormality exists) stored in the storage unit 41, the stage moving mechanism 22 and the head moving mechanism 23 are driven by the movement control unit 42, and the via hole is positioned below the head 3.

[0052] FIG. 10 is a cross-sectional view of the substrate 9 showing the via hole 93. In the example shown in FIG. 10, the bottom surface 931 of the via hole 93 is covered with a smear 96 (that is, a foreign substance which is the residue of the resin forming the insulating layer 95).

[0053] In the inspection apparatus 1 shown in FIG. 1, excitation light is irradiated from the excitation light emitting unit 311 onto the inspection region including the via hole 93 (step S11), and the inspection images and reflection spectra shown in FIGS. 11A and 11B are acquired (step S12). Subsequently, the excitation light emitting unit 311 is turned off and the white light emitting unit 312 is turned on, and white light is irradiated onto the inspection region (step S13). Then, the inspection images and reflection spectra shown in FIGS. 12A and 12B are acquired (step S14). Thereafter, the excitation light emitting unit 311 is turned on, and the inspection region is irradiated with both excitation light and white light simultaneously (step S15). Then, the inspection images and reflection spectra shown in FIGS. 13A and 13B are acquired (step S16). Note that the acquisition order of the above three inspection images and three reflection spectra may be changed as appropriate.

[0054] Next, the operator checks the inspection images and reflection spectra shown in FIGS. 11A, 11B, FIGS. 12A, 12B, and FIGS. 13A, 13B to inspect the via hole 93. In the inspection image shown in FIG. 11A, the bottom surface 931 of the via hole 93 also generates fluorescence in substantially the same manner as the surrounding insulating layer 95 and appears blue. Also, in the reflection spectrum shown in FIG. 11B (i.e., the reflection spectrum at the position of the black dot indicating the pinhole 327a in FIG. 11A), a peak exists at the wavelength of 430 nm corresponding to the above fluorescence. Therefore, the operator determines that there is a smear 96 on the bottom surface 931 of the via hole 93. Note that the smear 96 is thinner than the insulating layer 95, and the fluorescence from the smear 96 is weaker than the fluorescence from the insulating layer 95. Therefore, in the inspection image shown in FIG. 11A, the smear 96 appears as a darker blue than the blue color of the insulating layer 95.

[0055] To confirm the correctness of the above determination, the operator checks FIGS. 12A, 12B and FIGS. 13A, 13B. The reflection spectrum in FIG. 12B is somewhat similar to the above-mentioned reference spectrum (i.e., the reflection spectrum of white light by copper), but since the light amount is smaller than the reference spectrum, it is determined that the amount of reflected light from the wiring layer 94b is reduced by the smear 96. Also, in the inspection image shown in FIG. 13A, since the bottom surface 931 of the via hole 93 is a color in which a bright white similar to the insulating layer 95 and a color close to red similar to the wiring layer 94a are mixed, it is determined that the smear 96 is present on the wiring layer 94b. Further, in the reflection spectrum shown in FIG. 13B, since there are a similar waveform with a smaller light amount than the reference spectrum and a peak corresponding to the above fluorescence, it is determined that the smear 96 is present on the wiring layer 94b (step S17).

[0056] In the above inspection of the via hole 93 (step S17), instead of the determination by the operator, the inspection apparatus 1 may automatically detect the smear 96. For example, in the reflection spectrum shown in FIG. 11B (i.e., the reflection spectrum when excitation light is irradiated), the peak wavelength is obtained by the display control unit 43 etc. of the control unit 4. Then, the obtained peak wavelength is compared with the peak wavelength of the fluorescence stored in the storage unit 41 in advance (i.e., the peak wavelength of the fluorescence generated from the resin forming the insulating layer 95), and when the difference between both peak wavelengths is within a predetermined range (for example, 5 nm or less), it is determined by the display control unit 43 etc. that the smear 96 is present in the via hole 93.

[0057] In the inspection apparatus 1, as shown in FIG. 14, when the smear 96 is present only in a part of the bottom surface 931 of the via hole 93, for example, in the inspection image obtained by irradiating excitation light, the operator drives the stage moving mechanism 22 and / or the head moving mechanism 23 so that the black dot indicating the pinhole 327a is located on the smear 96. Thereafter, as described above, the inspection of the via hole 93 based on the inspection image and the reflection spectrum is performed (steps S11 to S17).

[0058] As shown in FIG. 15, there is a foreign object 97 different from the smear 96 on the bottom surface 931 of the via hole 93. When the foreign object 97 does not generate fluorescence by the above-described excitation light, in the reflection spectrum obtained by irradiating the excitation light, there is no peak corresponding to the fluorescence. Further, in the inspection image obtained by irradiating white light, the foreign object 97 is displayed in a color different from that of the wiring layer 94b (for example, black). The operator determines from these reflection spectra and inspection images that there is a foreign object 97 different from the smear 96 in the via hole 93.

[0059] Also, when the foreign object 97 generates fluorescence by the excitation light, the peak wavelength of the fluorescence is different from the peak wavelength of the fluorescence from the smear 96 (that is, 430 nm). In this case, in the reflection spectrum obtained by irradiating the excitation light, the peak corresponding to the fluorescence from the foreign object 97 appears at a position different from the peak corresponding to the fluorescence from the smear 96. Therefore, the operator determines that there is a foreign object 97 different from the smear 96 in the via hole 93. Note that in the inspection image obtained by irradiating the excitation light, the fluorescence from the foreign object 97 is captured, but it is not easy for the operator to distinguish the difference between the fluorescence and the fluorescence from the smear 96.

[0060] Note that the method for determining the presence or absence of foreign matter and the type of foreign matter (i.e., whether it is smear) in the via hole 93 may be variously changed. For example, the inspected images and reflection spectra when only white light is irradiated, and the inspected images and reflection spectra when excitation light and white light are simultaneously irradiated are not used for the determination, and the above determination may be made from the inspected images and reflection spectra when only excitation light is irradiated. Alternatively, the above determination may be made only from the inspected images and reflection spectra when excitation light and white light are simultaneously irradiated. Also, the above determination may be made from the inspected images and reflection spectra when only excitation light is irradiated, and the inspected images and reflection spectra when excitation light and white light are simultaneously irradiated. Furthermore, the presence or absence of foreign matter and the type of foreign matter may be determined only from the reflection spectrum without using the inspected image. The determination may be made by an operator as described above, or may be automatically made by the display control unit 43 or the like of the inspection apparatus 1.

[0061] As described above, the inspection apparatus 1 for inspecting the via hole 93 of the substrate 9 includes an optical irradiation unit 31 and a spectroscopic measurement unit 33. The optical irradiation unit 31 irradiates the inspected region including the via hole 93 on a laminated substrate (i.e., the substrate 9) in which the wiring layers 94a and 94b and the insulating layer 95 are alternately laminated with excitation light that generates fluorescence in the resin forming the insulating layer 95. The spectroscopic measurement unit 33 receives the reflected light from the inspected region and acquires a reflection spectrum. Thereby, the smear 96 and the foreign matter 97 other than the smear 96 in the via hole 93 can be accurately discriminated.

[0062] As described above, the inspection apparatus 1 is preferably disposed on the optical path from the inspection region toward the spectroscopic measurement unit 33, and further includes a filter unit (in the above example, the dichroic mirror 323) that guides light in a wavelength range different from the excitation light to the spectroscopic measurement unit 33. Thereby, it is possible to prevent the excitation light reflected in the inspection region from entering the spectroscopic measurement unit 33. Therefore, it is possible to prevent the peak of the excitation light having a wavelength relatively close to the fluorescence from the smear 96 or the like from appearing in the reflection spectrum acquired by the spectroscopic measurement unit 33. As a result, it is possible to accurately determine the presence or absence of the fluorescence in the reflection spectrum. Note that the filter unit is not limited to the dichroic mirror 323, and various structures can be used as long as they do not transmit the excitation light and guide only the light in a wavelength range different from the excitation light to the spectroscopic measurement unit 33.

[0063] The inspection apparatus 1 preferably further includes an imaging unit 34 and a display unit (that is, the display 107). The imaging unit 34 receives the reflected light from the inspection region and acquires an inspection image that is an image of the inspection region. The display 107 displays the inspection image acquired by the imaging unit 34 and the reflection spectrum acquired by the spectroscopic measurement unit 33. Thereby, the operator can easily visually recognize the state of the via hole 93. As a result, the inspection accuracy of the via hole 93 can be improved as compared with the case of determining only from the reflection spectrum.

[0064] As described above, it is preferable that the inspection apparatus 1 further includes a pinhole mirror 327 disposed on the optical path from the inspection area toward the spectroscopic measurement unit 33. In this case, the spectroscopic measurement unit 33 receives the light that has passed through the pinhole 327a of the pinhole mirror 327 among the reflected light from the inspection area. Further, the imaging unit 34 receives the light reflected by the pinhole mirror 327 among the reflected light from the inspection area. Thereby, at the bottom surface 931 of the via hole 93, the reflection spectrum of the minute area corresponding to the pinhole 327a can be acquired. Further, since the position of the black dot corresponding to the pinhole 327a on the inspection image can be moved while being confirmed on the display 107, the reflection spectrum of a desired position on the bottom surface 931 of the via hole 93 can be easily acquired. As a result, the inspection accuracy of the via hole 93 can be improved.

[0065] As described above, it is preferable that the light irradiation unit 31 includes an excitation light emission unit 311 that emits excitation light toward the inspection area and a white light emission unit 312 that emits white light toward the inspection area. Thereby, since the inspection of the via hole 93 can be performed based on both the measurement result by the excitation light and the measurement result by the white light, the inspection accuracy can be improved. For example, even a foreign object that does not generate fluorescence with the excitation light can be visually detected in the inspection image when irradiated with white light.

[0066] As described above, it is preferable that the light irradiation unit 31 can simultaneously irradiate the inspection area with the excitation light from the excitation light emission unit 311 and the white light from the white light emission unit 312. Thereby, even for a high aspect ratio via hole 93 where it is difficult to obtain a clear image of the bottom surface 931 with only white light and accurate observation is difficult, a relatively clear image of the bottom surface 931 can be obtained by using the fluorescence from the insulating layer 95 around the bottom surface 931. Also, in the inspection image, the boundary between the bottom surface 931 of the via hole 93 and the surrounding insulating layer 95 can be made clear. As a result, the inspection accuracy of the via hole 93 can be further improved.

[0067] As described above, the inspection method for inspecting the via hole 93 of the substrate 9 includes a step of irradiating an excitation light that generates fluorescence in the resin forming the insulating layer 95 to an inspection region including the via hole 93 on a laminated substrate (i.e., the substrate 9) in which the wiring layers 94a and 94b and the insulating layer 95 are alternately laminated (step S11 or step S15), a step of receiving the reflected light from the inspection region and acquiring a reflection spectrum (step S12 or step S16), and a step of inspecting the via hole 93 based on the reflection spectrum (step S17). Thereby, similarly to the above, it is possible to accurately discriminate between the smear 96 in the via hole 93 and the foreign matter 97 other than the smear 96.

[0068] In the above-described inspection apparatus 1, the excitation light emitting unit 311 includes an LED that emits excitation light, but may have other structures. For example, the excitation light emitting unit 311 may include an LD (Laser Diode) instead of the LED. Further, for example, as shown in FIG. 16, a band-pass filter 313 that extracts light of a predetermined wavelength (for example, light having a wavelength of 405 nm) from the white light emitted from the white light emitting unit 312 as excitation light may be provided in the light irradiation unit 31 as an excitation light emitting unit that emits excitation light.

[0069] Next, with reference to FIGS. 17 to 19, inspection apparatuses 1a to 1c according to the second to fourth embodiments of the present invention will be described. In the inspection apparatuses 1a to 1c, the wavelength of the excitation light irradiated to the inspection region of the substrate 9 can be switched among a plurality of wavelengths. Thereby, when a plurality of types of substrates 9 having different types of resins forming the insulating layer 95 (see FIG. 4) are included in the inspection target, by switching the wavelength of the excitation light according to the type of the resin (that is, selecting and irradiating excitation light having a wavelength at which the resin generates fluorescence), it is possible to inspect the plurality of types of substrates 9 with one inspection apparatus 1.

[0070] The inspection apparatus 1a shown in FIG. 17 has substantially the same configuration as the inspection apparatus 1 shown in FIG. 1 except that the light irradiation unit 31a includes a wavelength switching unit 36a. In the following description, the same reference numerals are given to the corresponding configurations in the inspection apparatus 1a as those in the inspection apparatus 1.

[0071] In addition to the above-described excitation light emitting unit 311, the light irradiation unit 31a includes one or more other excitation light emitting units 311 that emit excitation light having a wavelength different from that of the excitation light emitting unit 311. In the example shown in FIG. 17, the light irradiation unit 31a includes four excitation light emitting units 311 that emit excitation light having different wavelengths. Each excitation light emitting unit 311 is fixed to a frame 37 that is movable in the horizontal direction together with a corresponding dichroic mirror 323 and a first collimator lens 321. The dichroic mirror 323 fixed to the same frame 37 as each excitation light emitting unit 311 reflects the excitation light emitted from the excitation light emitting unit 311 and transmits light in a wavelength range different from that of the excitation light. Therefore, the four dichroic mirrors 323 have different wavelengths of the reflected light from each other.

[0072] The wavelength switching unit 36a is a light emitting unit moving mechanism that moves four frames 37 that respectively hold the excitation light emitting unit 311, the first collimator lens 321, and the dichroic mirror 323 in the horizontal direction. The wavelength switching unit 36a can move the four frames 37 independently. In the inspection apparatus 1a, an excitation light emitting unit 311 that emits excitation light having a wavelength that generates fluorescence in the resin is selected according to the type of the resin forming the insulating layer 95 of the substrate 9 to be inspected. Then, the frame 37 to which the excitation light emitting unit 311 is fixed is moved by the wavelength switching unit 36a, and the dichroic mirror 323 corresponding to the excitation light emitting unit 311 is disposed on the optical path between the inspection region of the substrate 9 and the spectroscopic measurement unit 33. Further, the dichroic mirror 323 corresponding to the other excitation light emitting units 311 is retracted out of the optical path from between the inspection region and the spectroscopic measurement unit 33. Thereby, excitation light having a wavelength suitable for the substrate 9 to be inspected is irradiated onto the inspection region on the substrate 9.

[0073] In this way, in the inspection apparatus 1a, the light irradiation unit 31a includes a wavelength switching unit 36a that switches the wavelength of the excitation light among a plurality of wavelengths. As a result, since the wavelength of the excitation light can be switched according to the type of resin forming the insulating layer 95, a plurality of types of substrates 9 can be inspected in the inspection apparatus 1a. That is, the versatility of the inspection apparatus 1a can be improved.

[0074] The inspection apparatus 1b shown in FIG. 18 has substantially the same configuration as the inspection apparatus 1 shown in FIG. 1, except that the light irradiation unit 31b includes a wavelength switching unit 36b. In the following description, the same reference numerals are given to the corresponding components in the inspection apparatus 1b as those in the inspection apparatus 1.

[0075] The wavelength switching unit 36b includes a filter plate 361b and a plate rotation mechanism 362b. The filter plate 361b is a substantially disk-shaped member in which a plurality of filters 363b are arranged in a circumferential shape. The plurality of filters 363b are band-pass filters that extract light of different predetermined wavelengths from white light. In the light irradiation unit 31b, a part of the white light emitted from the white light emission unit 312 is guided to the filter plate 361b by the half mirror 364b. The plate rotation mechanism 362b rotates the filter plate 361b and arranges one of the plurality of filters 363b on the optical path of the white light guided by the half mirror 364b. The plate rotation mechanism 362b is, for example, an electric motor.

[0076] In the inspection apparatus 1b, a filter 363b that extracts excitation light having a wavelength that causes fluorescence in the resin from white light is disposed on the optical path in accordance with the type of resin forming the insulating layer 95 (see FIG. 4) of the substrate 9 to be inspected. That is, the filter 363b is an excitation light emitting unit that emits excitation light. Then, the excitation light from the filter 363b is reflected by the mirror 368b and guided to the dichroic mirror 323. The dichroic mirror 323 in the inspection apparatus 1b is configured to reflect light in a wavelength range equal to or less than the longest wavelength among the excitation lights from the plurality of filters 363b and transmit light in a wavelength range longer than the longest wavelength. Therefore, the excitation light from the filter 363b is reflected by the dichroic mirror 323 and guided to the substrate 9. Thereby, excitation light having a wavelength suitable for the substrate 9 to be inspected is irradiated onto the inspection region on the substrate 9.

[0077] As described above, in the inspection apparatus 1b, the light irradiation unit 31b includes a wavelength switching unit 36b that switches the wavelength of the excitation light among a plurality of wavelengths. Thereby, since the wavelength of the excitation light can be switched according to the type of resin forming the insulating layer 95, it is possible to inspect a plurality of types of substrates 9 in the inspection apparatus 1b. That is, the versatility of the inspection apparatus 1b can be improved.

[0078] The inspection apparatus 1c shown in FIG. 19 has substantially the same configuration as the inspection apparatus 1 shown in FIG. 1, except that the light irradiation unit 31c includes a wavelength switching unit 36c. In the following description, the same reference numerals are given to the corresponding configurations in the inspection apparatus 1c as those in the inspection apparatus 1.

[0079] The wavelength switching unit 36c includes a spectroscope 365c, a slit 366c, and a spectroscope rotation mechanism 367c. The spectroscope 365c is an optical element that disperses (i.e., spectroscopically analyzes) white light into light of various wavelengths. The spectroscope 365c is, for example, a prism. In the inspection apparatus 1c, a part of the white light emitted from the white light emission unit 312 is guided to the spectroscope 365c by the half mirror 364c and the mirror 369c. The slit 366c has an aperture that allows only the light emitted from the spectroscope 365c in a predetermined direction (i.e., light of a predetermined wavelength) to pass through as excitation light. The spectroscope rotation mechanism 367c changes the wavelength of the light traveling from the spectroscope 365c to the aperture of the slit 366c by rotating the spectroscope 365c. The spectroscope rotation mechanism 367c is, for example, an electric motor.

[0080] In the inspection apparatus 1c, according to the type of resin forming the insulating layer 95 (see FIG. 4) of the substrate 9 to be inspected, excitation light having a wavelength that generates fluorescence in the resin is guided from the slit 366c to the dichroic mirror 323. That is, the spectroscope 365c and the slit 366c are excitation light emission units that emit excitation light. The excitation light is reflected by the dichroic mirror 323 and guided to the substrate 9. Thereby, excitation light having a wavelength suitable for the substrate 9 to be inspected is irradiated onto the inspection region on the substrate 9. Note that the spectroscope 365c may be another optical element such as a grating (i.e., a diffraction grating).

[0081] As described above, in the inspection apparatus 1c, the light irradiation unit 31c includes a wavelength switching unit 36c that switches the wavelength of the excitation light among a plurality of wavelengths. Thereby, since the wavelength of the excitation light can be switched according to the type of resin forming the insulating layer 95, it is possible to inspect a plurality of types of substrates 9 in the inspection apparatus 1c. That is, the versatility of the inspection apparatus 1c can be improved.

[0082] In the above-described inspection apparatuses 1, 1a to 1c, various modifications are possible.

[0083] For example, the structure of the substrate 9 inspected by the inspection apparatuses 1, 1a to 1c is not limited to the one in which the insulating layer 95 is exposed around the via hole 93 as described above, and may be variously modified.

[0084] The structures of the wavelength switching units 36a to 36c are not limited to those illustrated in FIGS. 17 to 19, and may be variously modified. Further, the wavelength switching units 36a to 36c may be omitted.

[0085] In the inspection apparatus 1, the excitation light and the white light do not necessarily need to be irradiated simultaneously. Also, In the technology related to the present invention when white light is not used for inspecting the substrate 9 or the like, the white light emitting unit 312 may be omitted. 。

[0086] The above-described pinhole mirror 327 does not necessarily need to be provided, and a half mirror or the like may be provided in place of the pinhole mirror 327.

[0087] In the inspection apparatus 1, when the detection of the smear 96 is automatically performed by the display control unit 43 or the like, the imaging unit 34 and the display unit (that is, the display 107) do not necessarily need to be provided. The same applies to the inspection apparatuses 1a to 1c.

[0088] In the inspection apparatuses 1, 1a to 1c, instead of the dichroic mirror 323, another filter unit that separates light in a wavelength range different from the excitation light from the excitation light and guides it to the spectroscopic measurement unit 33 may be provided. Further, the filter unit may be omitted.

[0089] In the inspection apparatuses 1, 1a to 1c, for example, the head moving mechanism 23 may be omitted, and a stage moving mechanism that allows the stage 21 to move relative to the head 3 in two horizontal directions (for example, the left - right direction in FIG. 1 and the direction perpendicular to the plane of FIG. 1) may be provided.

[0090] The configurations in the above - described embodiments and each modification example may be appropriately combined as long as they do not contradict each other.

Explanation of Reference Numerals

[0091] 1,1a to 1c inspection devices 9 substrates 31, 31a to 31c light irradiation units 33 spectroscopic measurement unit 34 imaging unit 36a to 36c wavelength switching units 93 via hole 94a, 94b wiring layers 95 insulating layer 107 display 311 excitation light emitting unit 312 white light emitting unit 313 band - pass filter 323 dichroic mirror 327 pinhole mirror 327a pinhole S11 to S17 steps

Claims

1. An inspection apparatus for inspecting via holes in a substrate, comprising: an excitation light emitting unit that irradiates an excitation light that generates fluorescence in a resin forming the insulating layer onto an inspection region including via holes on a laminated substrate in which wiring layers and insulating layers are alternately laminated; a white light emitting unit that emits white light onto the inspection region; a spectroscopic measurement unit that receives light from the inspection region and acquires a spectrum showing a light quantity distribution for each wavelength of the light; an imaging unit that receives light from the inspection region and acquires an inspection image that is an image of the inspection region; An inspection apparatus characterized by comprising the above.

2. The inspection apparatus according to Claim 1, further comprising: a filter unit that is disposed on an optical path from the inspection region toward the spectroscopic measurement unit and guides light in a wavelength range different from that of the excitation light to the spectroscopic measurement unit.

3. The inspection apparatus according to Claim 1 or 2, further comprising: a display unit that displays the inspection image acquired by the imaging unit and the spectrum acquired by the spectroscopic measurement unit.

4. The inspection apparatus according to any one of Claims 1 to 3, further comprising: a pinhole mirror disposed on an optical path from the inspection region toward the spectroscopic measurement unit, wherein the spectroscopic measurement unit receives light that has passed through the pinhole of the pinhole mirror among the light from the inspection region, and the imaging unit receives light that has been reflected by the pinhole mirror among the light from the inspection region.

5. The inspection apparatus according to any one of Claims 1 to 4, wherein: the excitation light from the excitation light emitting unit and the white light from the white light emitting unit can be simultaneously irradiated onto the inspection region.

6. The inspection apparatus according to any one of Claims 1 to 5, further comprising: a wavelength switching unit that switches the wavelength of the excitation light among a plurality of wavelengths.

7. An inspection method for inspecting via holes in a substrate, comprising: a) a step of irradiating an excitation light that generates fluorescence in a resin forming the insulating layer onto an inspection region including via holes on a laminated substrate in which wiring layers and insulating layers are alternately laminated; b) a step of emitting white light onto the inspection region; c) A step of receiving light from the inspection area and obtaining a spectrum showing the light quantity distribution for each wavelength of the light; d) A step of receiving light from the inspection area and obtaining an inspection image which is an image of the inspection area; e) A step of inspecting the via hole based on the spectrum and the inspection image; An inspection method characterized by comprising the above.

Images