KR20220133084A - Inspection apparatus and inspection method - Google Patents

Abstract

An inspection apparatus (1) for inspecting a via hole on a substrate (9) comprises a light emitting unit (31) and a spectroscopic measuring unit (33). The light emitting unit (31) emits excitation light, which generates fluorescence in a resin forming an insulating layer, to a region to be inspected including a via hole on a laminated substrate (9) in which wiring layers and insulating layers are alternately laminated. The spectroscopic measuring unit (33) receives reflective light from the corresponding inspected region and acquires a reflective spectrum. Accordingly, smears and foreign matters other than the smears in the via hole can be determined with good accuracy.

Description

INSPECTION APPARATUS AND INSPECTION METHOD

[REFERENCE TO RELATED APPLICATIONS]

This application claims the benefit of priority from Japanese Patent Application JP2021-049678 for which it applied on March 24, 2021, All the indications of this application are taken in here.

The present invention relates to a technique for inspecting a via hole in a substrate.

BACKGROUND ART Conventionally, in the production of a laminated substrate in which wiring layers and insulating layers are alternately laminated, laser via processing is performed. In laser via processing, in the laminated substrate during manufacture, by irradiating a laser beam to a part of the wiring layer, which is the uppermost layer, it penetrates the wiring layer and the insulating layer below the wiring layer, and lowers the wiring layer below the insulating layer. A via hole (also called a via hole or via) is formed. The inner surface of the via hole is plated with copper (Cu) or the like by a subsequent process to ensure electrical connection (ie, conduction state) between the upper and lower wiring layers.

In such laser via processing, a residue (that is, smear) of the resin forming the insulating layer may remain on the bottom surface of the via hole. The smear becomes a factor of a decrease in the reliability of the electrical connection between the wiring layers. Therefore, an inspection apparatus for inspecting the presence of smear in a via hole by irradiating excitation light to a plurality of via holes formed in the laminate substrate and receiving fluorescence generated from the smear with a photodiode or the like is used. When a smear is detected in the said test|inspection apparatus, a desmear process will be performed and a smear will be removed.

In addition, in International Publication No. 2017/130555 (Document 1), the presence or absence of resin (that is, the material of the insulating layer) in the via hole during formation by laser via processing is checked in parallel with processing of the via hole. technology is proposed. Specifically, excitation light is emitted toward the via hole during formation in parallel with the processing of the via hole, and fluorescence generated from the resin forming the insulating layer is received by a photodiode, whereby the resin in the via hole (i.e., material of the insulating layer) is checked. Then, when the formation of the via hole proceeds and the intensity of fluorescence from the via hole decreases to less than the threshold value, it is judged that the resin in the via hole has been sufficiently removed (that is, no smear is present).

By the way, foreign substances other than a smear may also exist in a via hole, and in order to remove foreign substances other than a smear, the removal process different from a desmear process is needed. However, the said foreign material may also generate|occur|produce fluorescence by irradiation of excitation light, and in this case, it is difficult to discriminate|distinguish a smear from a foreign material other than a smear with the above-mentioned inspection apparatus.

Currently, the operator visually checks the via hole with a fluorescence microscope or the like to determine whether or not foreign matter in the via hole is smear. There is a possibility that they may be different.

The present invention is for an inspection apparatus for inspecting a via hole in a substrate, and an object of the present invention is to accurately discriminate smear and foreign substances other than smear in a via hole.

An inspection apparatus according to a preferred embodiment of the present invention provides excitation light that generates fluorescence in a resin forming the insulating layer in a region to be inspected including a via hole on a laminated substrate in which wiring layers and insulating layers are alternately laminated. A light irradiation unit to irradiate, and a spectral measurement unit which receives the reflected light from the inspection target area and acquires a reflection spectrum.

ADVANTAGE OF THE INVENTION According to this invention, the smear in a via hole and foreign material other than a smear can be discriminated with high precision.

Preferably, the inspection apparatus further includes a filter unit disposed on an optical path from the region to be inspected toward the spectral measuring unit and guiding light of a wavelength band different from the excitation light to the spectroscopic measuring unit.

Preferably, the inspection device includes: an imaging unit configured to receive a reflected light from the inspection target region to acquire an inspection target image that is an image of the inspection target region; the inspection target image acquired by the imaging unit; A display unit for displaying the reflection spectrum acquired by the spectroscopic measurement unit is further provided.

Preferably, the inspection device further includes a pinhole mirror disposed on an optical path from the region to be inspected toward the spectral measurement unit. The spectral measurement unit receives the light that has passed through the pinhole of the pinhole mirror among the reflected light from the area to be inspected. The imaging unit receives the light reflected by the pinhole mirror among the light reflected from the area to be inspected.

Preferably, the light irradiation unit includes an excitation light output unit for emitting the excitation light toward the area to be inspected, and a white light emission unit for emitting white light toward the area to be inspected.

Preferably, the light irradiation unit is capable of simultaneously irradiating the excitation light from the excitation light output unit and the white light from the white light emission unit to the area to be inspected.

Preferably, the light irradiation unit includes a wavelength conversion unit that converts a wavelength of the excitation light between a plurality of wavelengths.

The present invention also relates to an inspection method for inspecting a via hole in a substrate. An inspection method according to a preferred embodiment of the present invention comprises: a) Excitation of generating fluorescence in a resin forming the insulating layer in a region to be inspected including a via hole on a laminated substrate in which wiring layers and insulating layers are alternately laminated A step of irradiating light; b) a step of receiving reflected light from the inspection target region to obtain a reflection spectrum; and c) a step of inspecting the via hole based on the reflection spectrum.

The above-mentioned and other objects, features, aspects, and advantages are made clear by the detailed description of the present invention given below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the inspection apparatus which concerns on 1st Embodiment.
Fig. 2 is a diagram showing the configuration of a computer realizing a control unit.
Fig. 3 is a block diagram showing the function of the control unit.
4 is a cross-sectional view of the substrate.
Fig. 5A is a diagram showing an image to be inspected when excitation light is irradiated.
5B is a diagram showing a reflection spectrum when excitation light is irradiated.
6A is a diagram showing an image to be inspected when irradiated with white light.
6B is a diagram showing a reflection spectrum when white light is irradiated.
Fig. 7A is a diagram showing an image to be inspected when excitation light and white light are irradiated.
7B is a diagram showing reflection spectra when irradiated with excitation light and white light.
Fig. 8A is a diagram showing an image to be inspected when irradiated with white light;
Fig. 8B is a diagram showing an image to be inspected when excitation light is irradiated.
Fig. 9 is a diagram showing the flow of inspection of via holes.
10 is a cross-sectional view of the substrate.
11A is a diagram showing an image to be inspected when excitation light is irradiated.
11B is a diagram showing a reflection spectrum when excitation light is irradiated.
12A is a diagram showing an image to be inspected when irradiated with white light.
12B is a diagram showing a reflection spectrum when irradiated with white light.
13A is a diagram showing an image to be inspected when excitation light and white light are irradiated.
13B is a diagram showing reflection spectra when irradiated with excitation light and white light.
14 is a cross-sectional view of the substrate.
15 is a cross-sectional view of the substrate.
16 : is a figure which shows the structure of another test|inspection apparatus.
Fig. 17 is a diagram showing the configuration of the inspection apparatus according to the second embodiment.
18 : is a figure which shows the structure of the inspection apparatus which concerns on 3rd Embodiment.
19 : is a figure which shows the structure of the inspection apparatus which concerns on 4th Embodiment.

1 : is a figure which shows the structure of the inspection apparatus 1 which concerns on 1st Embodiment of this invention. The inspection apparatus 1 is an apparatus for inspecting via holes (also called via holes or vias) formed in the 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 a 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 between the wiring layers adjacent in the lamination direction. In the following description, the laminated substrate 9 is also simply called a "substrate 9".

A large number of via holes are formed in the upper surface 91 of the substrate 9 . The said via hole is a hole which penetrates through the wiring layer of the uppermost layer and the insulating layer adjacent to the lower side of the said wiring layer, and makes the wiring layer adjacent to the lower side of the said insulating layer as a bottom. Foreign substances may exist on the bottom surface of the via hole. The foreign material is, for example, a smear (that is, a residue of the resin forming the insulating layer) generated during the processing of the via hole. Foreign substances other than smear (for example, a resin different from the resin forming the insulating layer) may exist on the bottom surface of the via hole.

The inspection apparatus 1 is an apparatus which inspects the foreign material when a foreign material exists in the via hole formed in the upper surface 91 of the substrate 9 . The inspection apparatus 1 inspects, for example, a via hole in which a foreign material was detected by an external appearance inspection apparatus among a plurality of via holes on the substrate 9, and determines whether the foreign material is a smear or a foreign material other than the smear. is used for

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 configuration of the inspection device 1 . In addition, in FIGS. 16-19 mentioned later, illustration of the control part 4 is abbreviate|omitted.

The stage 21 is arrange|positioned below the head 3, and hold|maintains the board|substrate 9 in a horizontal state from below. The stage 21 is, for example, a buffer chuck that sucks and holds the lower surface of the substrate 9 , or a mechanical chuck that mechanically limits the movement of the substrate 9 in the horizontal direction.

The stage moving mechanism 22 is a moving mechanism that relatively moves the stage 21 with respect to the head 3 in a horizontal direction (ie, 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 a figure. The driving 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 changed in various ways.

When inspecting the via hole of the substrate 9 on the stage 21 , the head 3 irradiates the substrate 9 with light and receives the reflected light from the substrate 9 . The detail of the structure of the head 3 is mentioned later. The head moving mechanism 23 is a moving mechanism that relatively moves the head 3 in the horizontal direction with respect to the stage 21 . In the example shown in FIG. 1 , the head moving mechanism 23 moves the head 3 in a direction perpendicular to the paper surface (that is, substantially parallel to the upper surface 91 of the substrate 9 , and in the stage moving mechanism 22 ) moves in a straight line in a direction perpendicular to the direction of movement by The driving 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 changed in various ways.

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

The light irradiation unit 31 irradiates light onto the area to be inspected including the via hole on the substrate 9 . The light irradiation unit 31 includes an excitation light output unit 311 and a white light emission unit 312 . The excitation light output unit 311 emits the excitation light toward the inspection target region of the substrate 9 . The excitation light is light of a wavelength that causes fluorescence in the resin forming the insulating layer of the substrate 9 . As the excitation light output section 311, for example, an LED (Light Emitting Diode) is usable. For example, excitation light having a wavelength of 405 nm is emitted from the excitation light output unit 311, and fluorescence in a wavelength range having a peak of 430 nm is generated from the resin forming the insulating layer. In addition, the wavelength range of fluorescence and the wavelength of excitation light generating fluorescence vary variously depending on the type of resin. Moreover, in the wiring layer of the board|substrate 9, fluorescence does not generate|occur|produce by irradiation of excitation light. When a foreign material is present on the substrate 9, when the foreign material is irradiated with excitation light, fluorescence may or may not be generated depending on the type of the foreign material. When a foreign material generates fluorescence, the wavelength range of the fluorescence is different from the wavelength range of the fluorescence generated by the insulating layer.

The white light emitting unit 312 emits white light (that is, light of a broadband wavelength) toward the inspection target area of the substrate 9 . As the white light emitting portion 312, for example, an LED is usable. In the inspection apparatus 1, light can be emitted from only one of the excitation light output part 311 and the white light output part 312, and light can also be emitted simultaneously from both. In FIG. 1, the optical axis of the light emitted from the excitation light output part 311 and the white light output part 312 is shown by the dashed-dotted line.

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 , and a condensing lens. A 326 , a pinhole mirror 327 , and an imaging lens 328 are provided.

The excitation light emitted from the excitation light output unit 311 is guided to the dichroic mirror 323 through 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 through the objective lens 325 . The excitation light is substantially condensed on the upper surface 91 of the substrate 9 and is irradiated to the area to be inspected. Further, the white light emitted from the white light output unit 312 is guided to the half mirror 324 through 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 through the objective lens 325 . The white light is substantially condensed on the upper surface 91 of the substrate 9 and irradiated to the area to be inspected.

The light reflected in the area to be inspected (that is, light reflected from the area to be inspected) 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 target region on the substrate 9 toward the spectroscopic measurement unit 33 . The dichroic mirror 323 reflects the excitation light among the reflected light from the area to be inspected, 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 band different from the excitation light from the excitation light and guides it to the spectroscopic measurement unit 33 . The light transmitted through the dichroic mirror 323 (that is, light in a wavelength region different from that of the excitation light) is guided to the pinhole mirror 327 through the condensing lens 326 . The pinhole mirror 327 is disposed on the optical path of the reflected light from the region to be inspected toward the spectroscopic measurement unit 33 , and is optically substantially conjugated to the upper surface 91 of the substrate 9 .

The light that has passed through the pinhole 327a of the pinhole mirror 327 is guided to the spectral measuring unit 33 and received by the spectral measuring unit 33 . The spectral measurement unit 33 acquires a spectrum of the received light (that is, light in a wavelength region different from that of the excitation light among the reflected light from the region to be inspected). In the following description, the spectrum (that is, the spectrum of the reflected light from the area|region to be inspected) acquired by the spectral measurement part 33 is also called "reflection spectrum". The reflection spectrum acquired by the spectral measurement unit 33 is sent to the control unit 4 .

The spectral measurement unit 33 includes, for example, a grating (ie, a diffraction grating) 331 and a spectral analysis unit 332 . The grating 331 is an optical element that disperses (that is, splits) the light incident on the spectral measurement unit 33 into light of various wavelengths. The spectral analysis unit 332 includes a plurality of light-receiving elements that respectively receive light of a plurality of wavelengths that have been separated by the grating 331 . As the said light receiving element, line sensors, such as CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge Coupled Devices), and an image sensor can be used, for example. In addition, in the spectral measurement part 33, instead of the grating 331, other spectrometers, such as a prism, may be used.

The light reflected by the pinhole mirror 327 described above is guided to the imaging unit 34 through the imaging lens 328 . The imaging unit 34 transmits the dichroic mirror 323 and receives the light reflected by the pinhole mirror 327 among the reflected light from the inspection target region, and generates an inspection target image that is an image of the inspection target region. acquire As described above, since the pinhole mirror 327 is substantially conjugated to the upper surface 91 of the substrate 9, the pinhole 327a of the pinhole mirror 327 is reflected as a black spot on the image to be inspected. The image to be inspected obtained by the imaging unit 34 is sent to the control unit 4 . As the imaging unit 34, for example, an image sensor such as CMOS or CCD can be used.

In the example shown in Fig. 1, the optical axis of the light irradiated to the inspection target region of the substrate 9 through the objective lens 325 is perpendicular to the upper surface 91 of the substrate 9, and the optical axis and the inspection target region The optical axes of the reflected light incident on the objective lens 325 coincide with each other. That is, in the head 3, coaxial falling illumination is realized. In addition, the structure of the detection optical system 32 in the head 3 may be changed suitably. In addition, the configurations of the excitation light output unit 311 , the white light output unit 312 , the spectral measurement unit 33 , and the imaging unit 34 may also be appropriately changed.

FIG. 2 is a diagram showing the configuration of the computer 100 realizing 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 connecting the processor 101 , the memory 102 , and the input/output unit 103 . The memory 102 stores programs and various types of information. The processor 101 executes various processes (eg, numerical calculation and image processing) while using the memory 102 or the like according to a program or the like stored in the memory 102 . The input/output unit 103 includes a keyboard 105 and a mouse 106 for receiving input from an operator, and a display 107 for displaying output from the processor 101 and the like. In addition, the control part 4 may be a programmable logic controller (PLC:Programmable Logic Controller), a circuit board, etc., and the combination of these and one or more computers may be sufficient as it.

3 is a block diagram showing the function of the control unit 4 realized by the computer 100. As shown in FIG. In FIG. 3, the structure other than the control part 4 is also shown together. 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 pieces of information related to the inspection of the via hole. The storage unit 41 stores, for example, positional information of via holes that need to be inspected by the inspection apparatus 1 among a large number of via holes on the substrate 9 . The position information is input via the input/output unit 103 by an operator or the like, for example. Or, the said positional information is sent to the control part 4 from the external appearance inspection apparatus etc. which acquired the said positional information. The storage unit 41 also stores the reflection spectrum sent from the spectral measurement unit 33 to the control unit 4 and the inspection subject image sent from the imaging unit 34 to the control unit 4 as described above. .

The movement control unit 42 is mainly realized by the processor 101 . The movement control unit 42 drives the stage movement mechanism 22 and the head movement mechanism 23 based on the above-described position information of the via hole stored in the storage portion 41 , thereby The irradiation position of the light is moved onto the area to be inspected including the via hole. The display control unit 43 is mainly realized by the processor 101 . The display control unit 43 causes the display 107 to display the above-described reflection spectrum and the image to be inspected stored in the storage unit 41 by controlling the display 107 or the like serving as the display unit.

4 is a cross-sectional view of the substrate 9 showing the via hole 93 . In the example shown in FIG. 4 , foreign substances such as smear do not exist in the via hole 93 , and the via hole 93 is not actually an inspection target of the inspection apparatus 1 . A case where the via hole 93 is inspected with the inspection device 1 will be described. In the example shown in FIG. 4 , an opening 941 including a via hole 93 and larger than the via hole 93 is formed in the uppermost wiring layer 94a, and a via hole is formed from the opening 941 . The insulating layer 95 around the 93 is exposed. Moreover, in the bottom surface 931 of the via hole 93, the upper surface of the 2nd-layer wiring layer 94b is exposed. In addition, although the bottom surface 931 of the via hole 93 is drawn as a plane in FIG. 4, it may be other shapes (for example, the concave shape with a center dented rather than a periphery part).

5A and 5B show imaging when excitation light is irradiated from the excitation light output unit 311 shown in FIG. 1 to the inspection target region including the via hole 93 in the inspection device 1 . It is a figure which shows the to-be-inspected image acquired by the part 34, and the reflection spectrum acquired by the spectral measurement part 33. FIG. The inspection target image shown in FIG. 5A is acquired in the state aligned so that the pinhole 327a of the pinhole mirror 327 mentioned above may be located on the bottom surface 931 of the via hole 93. As shown in FIG. The same applies to other inspected images, which will be described later.

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 is transmitted to the spectral measurement unit 33 and the imaging unit 34. do not enter For this reason, in the to-be-inspected image shown in FIG. 5A, the bottom surface 931 of the via hole 93 is reflected as a substantially circular black area|region. In the actual inspection target image, the pinhole 327a of the pinhole mirror 327 is included in the bottom surface 931 of the via hole 93 as a black spot. In order to do this, the pinhole 327a is shown as a white dot.

Only light from the region corresponding to the pinhole 327a is incident on the spectral measurement unit 33 . In the example shown in FIG. 5A , the light from the pinhole 327a is excitation light, and as described above, it is reflected by the dichroic mirror 323 and does not enter the spectral measurement unit 33 . Therefore, the reflection spectrum shown in FIG. 5B shows approximately 0 in each wavelength. Naturally, in the reflection spectrum, a peak corresponding to the excitation light (that is, a peak at a wavelength of 405 nm) does not exist.

The insulating layer 95 around the via hole 93 generates fluorescence by irradiation with excitation light. The fluorescence passes through the dichroic mirror 323 and enters the imaging unit 34 . For this reason, in the to-be-inspected image, the insulating layer 95 is reflected as a substantially annular blue area|region. In addition, as described above, only light from the region corresponding to the pinhole 327a of the pinhole mirror 327 enters the spectral measurement unit 33, and therefore the fluorescence is not incident. Therefore, in the reflection spectrum shown in FIG. 5B, a peak corresponding to fluorescence (that is, a peak at a wavelength of 430 nm) does not exist.

The excitation light reflected by the wiring layer 94a around the opening 941 is reflected by the dichroic mirror 323 and does not enter the spectral measurement unit 33 and the imaging unit 34 . For this reason, in the to-be-inspected image shown to FIG. 5A, the wiring layer 94a is reflected as a black area|region around the insulating layer 95. As shown in FIG.

6A and 6B are diagrams showing an inspection target image and a reflection spectrum when white light is irradiated from the white light emitting unit 312 to the inspection target region in the inspection apparatus 1, respectively. In the image to be inspected shown in FIG. 6A , the wiring layer 94b of the bottom surface 931 of the via hole 93 and the wiring layer 94a around the insulating layer 95 are made of copper, so they have a color close to red. It shines. In addition, since white light is harder to reach to the wiring layer 94b of the bottom surface 931 of the via hole 93 than the wiring layer 94a of the uppermost layer, it is reflected in red darker than the wiring layer 94a in the image to be inspected. In addition, the insulating layer 95 is reflected in a color closer to gray than the wiring layers 94a and 94b. White light reflected by the wiring layer 94b of the bottom surface 931 of the via hole 93 (except for 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 . For this reason, the reflection spectrum shown in FIG. 5B shows the spectrum substantially the same as the reflection spectrum of the white light by copper.

7A and 7B are diagrams each showing an inspection target image and a reflection spectrum when the inspection target region is simultaneously irradiated with excitation light and white light in the inspection device 1 . In the inspection target image shown in FIG. 7A , the wiring layer 94b of the bottom surface 931 of the via hole 93 and the wiring layer 94a around the insulating layer 95 are close to red as described above. shine with color Since the insulating layer 95 generates fluorescence, it is reflected in a color closer to white than that of the wiring layers 94a and 94b. In addition, since the fluorescence from the insulating layer 95 is also irradiated to the inside of the via hole 93, in the image to be inspected shown in FIG. 7A, the wiring layer 94b of the bottom surface 931 of the via hole 93 is It shines in red brighter than the inspection target image shown in FIG. 6A (that is, the inspection target image imaged only with white light). Accordingly, the bottom surface 931 of the via hole 93 can be observed clearly. In addition, in the to-be-inspected image shown in FIG. 7A, the boundary of the bottom surface 931 of the via hole 93, and the insulating layer 95 also becomes clearer than the to-be-inspected image shown in FIG. 6A. Therefore, by simultaneously irradiating the excitation light and the white light to the area to be inspected, the observation of the bottom surface 931 of the via hole 93 becomes easier compared to the case where only the white light is irradiated.

In the example shown in FIG. 7A , among the white light and the excitation light reflected by the wiring layer 94b of the bottom surface 931 of the via hole 93, white light (however, light having the same wavelength as the excitation light is excluded) is dichroic. Although it passes through the loic mirror 323 and the pinhole 327a and is incident on the spectral measuring unit 33 , the excitation light is reflected by the dichroic mirror 323 and does not enter the spectroscopic measuring unit 33 . For this reason, the reflection spectrum shown in FIG. 7B shows the spectrum substantially the same as the reflection spectrum of the white light by copper.

In inspection of the board|substrate 9 using the inspection apparatus 1, an operator confirms the to-be-tested image and reflection spectrum shown in FIGS. It is judged that it does not exist. Specifically, for example, in the reflection spectrum shown in Figs. 5B and 7B, a peak corresponding to the fluorescence generated by the insulating layer 95 (that is, a peak at a wavelength of 430 nm) does not exist. By confirming, it is determined that smear does not exist on the bottom surface 931 of the via hole 93 . In addition, by confirming that the reflection spectrum shown in FIGS. 6B and 7B substantially coincides with the previously acquired reference spectrum (that is, the reflection spectrum of white light by copper), to the bottom surface 931 of the via hole 93 It is judged that there are no foreign substances other than smear. Moreover, in the to-be-inspected image shown to FIG. 5A, FIG. 6A, 7A WHEREIN: It is confirmed visually that a foreign material does not exist in the via hole 93. As shown in FIG. In addition, the method of judging the presence or absence of a foreign material using the image to be inspected and the reflection spectrum may be changed in various ways.

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 image to be inspected, for example, the depth of the via hole 93 is bright enough to be observed. (that is, the distance in the vertical direction 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 excitation light is irradiated, as described above, fluorescence from the insulating layer 95 is irradiated to the inside of the via hole 93, so that in the image to be inspected, the bottom surface of the via hole 93 ( 931) becomes brighter. For this reason, even if the depth of the via hole 93 is the via hole 93 which is larger than 2/3 of the diameter of the upper end opening, observation of the bottom surface 931 becomes possible.

Fig. 8A is a graph showing a bottom surface 931 of the via hole 93 by irradiating only white light to a via hole 93 having a relatively large depth (that is, a high aspect ratio) with respect to the diameter of the top opening. inspection image. 8B is an inspection target image obtained by irradiating excitation light to the via hole 93 and capturing the bottom surface 931 of the via hole 93 . In FIG. 8A , light hardly reaches the bottom surface 931 of the via hole 93 so that the position of the bottom surface 931 is faintly known, whereas in FIG. 8B , the via hole 93 The bottom surface 931 of the can be observed relatively clearly.

Next, the flow of the inspection of a via hole using the inspection apparatus 1 is demonstrated, referring FIG. 9 . First, the stage moving mechanism 22 and the head are moved by the movement control unit 42 based on the position information of the via hole to be inspected (that is, the via hole in which any abnormality exists) stored in the storage unit 41 . The mechanism 23 is driven, and the via hole is located below the head 3 .

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 the smear 96 (that is, the foreign material which is a residue of resin which forms the insulating layer 95).

In the inspection apparatus 1 shown in FIG. 1 , the excitation light is irradiated from the excitation light output unit 311 to the inspection target region including the via hole 93 (step S11), as shown in FIGS. 11A and 11B . An inspection target image and a reflection spectrum are acquired (step S12). Subsequently, the excitation light output section 311 is turned off and the white light output section 312 is turned on, and white light is irradiated to the area to be inspected (step S13). Then, the image to be inspected and the reflection spectrum shown in Figs. 12A and 12B are acquired (step S14). Thereafter, the excitation light output unit 311 is turned on, and the excitation light and white light are simultaneously irradiated to the area to be inspected (step S15). Then, the inspection target image and the reflection spectrum shown in Figs. 13A and 13B are acquired (step S16). In addition, the order of acquisition of the above-mentioned three to-be-inspected image and three reflection spectra may be changed suitably.

Next, the operator inspects the via hole 93 by confirming the inspection target image and the reflection spectrum shown in FIGS. 11A, 11B, 12A, 12B, and 13A, 13B. In the image to be inspected shown in Fig. 11A, the bottom surface 931 of the via hole 93 also emits fluorescence substantially the same as the surrounding insulating layer 95, and reflects blue. Moreover, in the reflection spectrum shown in FIG. 11B (that is, the reflection spectrum at the position of the sunspot which shows the pinhole 327a in FIG. 11A), a peak exists at the position of the wavelength 430 nm corresponding to the said fluorescence. Therefore, it is judged by the operator that the smear 96 is present in the bottom surface 931 of the via hole 93 . In addition, since 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, in the image to be inspected shown in Fig. 11A, the smear 96 is insulating. It illuminates with a darker blue than the blue of layer 95 .

The operator confirms FIGS. 12A and 12B and FIGS. 13A and 13B for confirming whether the judgment is correct or not. The reflection spectrum of Fig. 12B is somewhat similar to the above-mentioned reference spectrum (that is, the reflection spectrum of white light by copper), but since the amount of light is smaller than the reference spectrum, the light quantity is lowered from the wiring layer 94b by the smear 96. It is judged that the amount of reflected light is decreasing. Further, in the image to be inspected shown in Fig. 13A, the bottom surface 931 of the via hole 93 is a mixture of a bright white color similar to the insulating layer 95 and a color close to red similar to the wiring layer 94a. From this, it is judged that the smear 96 is present on the wiring layer 94b. Further, in the reflection spectrum shown in Fig. 13B, it is judged that the smear 96 is present on the wiring layer 94b from the presence of a similar waveform with a light amount smaller than the reference spectrum and a peak corresponding to the fluorescence ( step S17).

In the inspection (step S17) of the via hole 93 mentioned above, the detection of the smear 96 may be performed automatically by the inspection apparatus 1 instead of the judgment by an operator. For example, in the reflection spectrum shown in FIG. 11B (that is, the reflection spectrum when excitation light is irradiated), the peak wavelength is calculated|required by the display control part 43 etc. of the control part 4 . Then, the obtained peak wavelength is compared with the peak wavelength of fluorescence previously stored in the storage unit 41 (that is, the peak wavelength of fluorescence generated from the resin forming the insulating layer 95), and the difference between both peak wavelengths is When it is within a predetermined range (for example, 5 nm or less), it is determined that the smear 96 is present in the via hole 93 by the display control unit 43 or the like.

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

As shown in FIG. 15 , a foreign material 97 different from the smear 96 is present on the bottom surface 931 of the via hole 93, and the foreign material 97 generates fluorescence by the above-described excitation light. If not, in the reflection spectrum obtained by irradiating the excitation light, there is no peak corresponding to the fluorescence. Moreover, in the to-be-inspected image obtained by irradiating white light, the foreign material 97 is displayed in the color (for example, black) different from the wiring layer 94b. The operator judges that the foreign material 97 different from the smear 96 exists in the via hole 93 from these reflection spectra and the to-be-inspected image.

In addition, when the foreign material 97 generates fluorescence by 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 material 97 appears at a different position from the peak corresponding to the fluorescence from the smear 96, so the operator can It is determined that a foreign material 97 different from the smear 96 is present in the via hole 93 . Moreover, although fluorescence from the foreign material 97 is reflected in the image to be inspected obtained by irradiating the excitation light, it is not easy for the operator to discriminate the difference between the fluorescence and the fluorescence from the smear 96 .

In addition, the determination method of the presence or absence of a foreign material in the via hole 93, and the kind of foreign material (namely, whether it is smear) may be changed variously. For example, the inspection target image and reflection spectrum when only white light is irradiated, and the inspection target image and reflection spectrum when excitation light and white light are simultaneously irradiated are not used for the determination, but when only excitation light is irradiated The above-mentioned judgment may be performed from the to-be-inspected image and reflection spectrum of . Alternatively, the above judgment may be made only from the image to be inspected and the reflection spectrum when the excitation light and white light are simultaneously irradiated. In addition, the above-mentioned judgment may be implemented from the to-be-inspected image and reflection spectrum when only excitation light is irradiated, and the to-be-inspected image and reflection spectrum when excitation light and white light are simultaneously irradiated. Furthermore, the presence or absence of a foreign material and the kind of foreign material may be judged only from the reflection spectrum without using the to-be-inspected image. As mentioned above, the said determination may be implemented by an operator, and may be performed automatically by the display control part 43 of the inspection apparatus 1, etc.

As described above, the inspection apparatus 1 for inspecting the via hole 93 of the substrate 9 includes a light irradiation unit 31 and a spectroscopic measurement unit 33 . The light irradiation part 31 is insulated from the area to be inspected including the via hole 93 on the laminated substrate (that is, the substrate 9) in which the wiring layers 94a and 94b and the insulating layer 95 are alternately laminated. The resin forming the layer 95 is irradiated with excitation light for generating fluorescence. The spectral measurement unit 33 receives the reflected light from the area to be inspected and acquires a reflection spectrum. Thereby, the smear 96 in the via hole 93 and the foreign material 97 other than the smear 96 can be discriminated with high precision.

As described above, the inspection device 1 is preferably arranged on an optical path from the region to be inspected toward the spectroscopic measurement unit 33, and transmits light in a wavelength range different from that of the excitation light into the spectroscopic measurement unit 33 . It further includes a filter unit (the dichroic mirror 323 in the above example) leading to . Thereby, it is possible to prevent the excitation light reflected from the inspection target region from entering the spectroscopic measurement unit 33 . Accordingly, it is possible to prevent the occurrence of a peak of excitation light having a relatively close wavelength to fluorescence from the smear 96 or the like in the reflection spectrum obtained by the spectroscopic measurement unit 33 . As a result, the presence or absence of the fluorescence in the reflection spectrum can be determined with high accuracy. In addition, the filter unit is not limited to the dichroic mirror 323, and as long as it does not transmit the excitation light and guides only light in a wavelength band different from that of the excitation light to the spectroscopic measurement unit 33, it may have various structures. Available.

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 target region and acquires an inspection target image that is an image of the inspection target region. The display 107 displays the image to be inspected acquired by the imaging unit 34 and the reflection spectrum acquired by the spectroscopic measurement unit 33 . Thereby, the operator can visually recognize the state of the via hole 93 easily. As a result, compared with the case of judging only from the reflection spectrum, the inspection accuracy of the via hole 93 can be improved.

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

As described above, the light irradiation unit 31 includes an excitation light output unit 311 for emitting excitation light toward the inspection target region, and a white light emission unit 312 for emitting white light toward the inspection target region. it is preferable 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 if it is a foreign material which does not generate|occur|produce fluorescence by excitation light, it becomes possible to visually detect in the to-be-tested image when white light is irradiated.

As described above, it is preferable that the light irradiation section 31 can simultaneously irradiate the excitation light from the excitation light output section 311 and the white light from the white light output section 312 to the area to be inspected. Thereby, the fluorescence from the insulating layer 95 around the bottom surface 931 is also difficult for the high-aspect-ratio via holes 93 that are difficult to accurately observe because it is difficult to acquire a clear image of the bottom surface 931 only with white light. By using , a relatively clear image of the bottom surface 931 can be acquired. Further, in the image to be inspected, 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.

As described above, the inspection method for inspecting the via hole 93 of the substrate 9 is a laminate substrate in which wiring layers 94a and 94b and insulating layers 95 are alternately laminated (ie, substrate 9). A step of irradiating an excitation light for generating fluorescence to the resin forming the insulating layer 95 to a region to be inspected including the via hole 93 on the upper part (Step S11 or Step S15); A step of receiving reflected light to obtain a reflection spectrum (step S12 or step S16), and a step of inspecting the via hole 93 based on the reflection spectrum (step S17) are provided. Thereby, similarly to the above, the smear 96 in the via hole 93 and the foreign material 97 other than the smear 96 can be discriminated with high accuracy.

In the inspection apparatus 1 described above, the excitation light output unit 311 is provided with an LED that emits the excitation light, but may have a different structure. For example, the excitation light output unit 311 may include an LD (Laser Diode) instead of an LED. Further, for example, as shown in Fig. 16, a band-pass filter 313 that extracts, as excitation light, light of a predetermined wavelength (eg, light of wavelength 405 nm) from white light emitted from the white light output unit 312 . ) may be formed in the light irradiation unit 31 as an excitation light output unit for emitting excitation light.

Next, the inspection apparatuses 1a-1c which concern on 2nd - 4th Embodiment of this invention are demonstrated, referring FIGS. 17-19. In inspection apparatus 1a-1c, it is possible to switch the wavelength of the excitation light irradiated to the to-be-inspected area|region of the board|substrate 9 among several wavelength. Accordingly, when a plurality of types of substrates 9 having different types of resin forming the insulating layer 95 (refer to Fig. 4) are included in the inspection object, the wavelength of the excitation light is switched according to the type of the resin (that is, , by selecting and irradiating excitation light having a wavelength at which the resin generates fluorescence), the plurality of types of substrates 9 can be inspected with one inspection device 1 .

The inspection apparatus 1a shown in FIG. 17 is equipped with the structure substantially the same as the inspection apparatus 1 shown in FIG. 1 except the point that the light irradiation part 31a is equipped with the wavelength conversion part 36a. In the following description, the code|symbol same as the structure corresponding to the inspection apparatus 1 is attached|subjected to each structure of the inspection apparatus 1a.

The light irradiation unit 31a includes, in addition to the above-described excitation light output unit 311 , one or more other excitation light emission units 311 for emitting excitation light having a wavelength different from that of the excitation light emission unit 311 . . In the example shown in FIG. 17, the light irradiation part 31a is provided with the four excitation light output parts 311 which emit the excitation light of mutually different wavelength. Each excitation light output unit 311, together with a corresponding dichroic mirror 323 and a first collimator lens 321, is fixed to a frame 37 movable in the horizontal direction. A dichroic mirror 323 fixed to the same frame 37 as each of the excitation light output units 311 reflects the excitation light emitted from the excitation light output unit 311, and has a wavelength range different from that of the excitation light. transmit light. Accordingly, the wavelengths of the reflected light of the four dichroic mirrors 323 are different from each other.

The wavelength conversion unit 36a is a light output that horizontally moves the four frames 37 holding the excitation light output unit 311 , the first collimator lens 321 and the dichroic mirror 323 , respectively. It is a vice-moving device. The wavelength conversion unit 36a can move the four frames 37 independently, respectively. In the inspection apparatus 1a, in accordance with the type of resin forming the insulating layer 95 of the substrate 9 to be inspected, an excitation light emitting unit 311 for emitting excitation light of a wavelength that causes fluorescence in the resin is provided. is chosen Then, the frame 37 to which the excitation light emitting unit 311 is fixed is moved by the wavelength conversion unit 36a, and the dichroic mirror 323 corresponding to the excitation light emitting unit 311 is moved. , disposed on the optical path between the inspection target region of the substrate 9 and the spectroscopic measurement unit 33 . Further, the dichroic mirror 323 corresponding to the other excitation light emitting portion 311 is retracted out of the optical path from between the inspected region and the spectroscopic measurement portion 33 . Thereby, excitation light of a wavelength suitable for the substrate 9 to be inspected is irradiated onto the region to be inspected on the substrate 9 .

Thus, in the inspection apparatus 1a, the light irradiation part 31a is equipped with the wavelength conversion part 36a which switches the wavelength of the excitation light between several wavelengths. Thereby, since the wavelength of excitation light can be switched according to the kind of resin which forms the insulating layer 95, in the test|inspection apparatus 1a, the test|inspection of several types of board|substrates 9 can be performed. That is, the versatility of the inspection apparatus 1a can be improved.

The inspection apparatus 1b shown in FIG. 18 is provided with the structure substantially the same as the inspection apparatus 1 shown in FIG. 1 except the point that the light irradiation part 31b is equipped with the wavelength conversion part 36b. In the following description, the code|symbol same as the structure corresponding to the inspection apparatus 1 is attached|subjected to each structure of the inspection apparatus 1b.

The wavelength conversion 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 the some filter 363b is arrange|positioned on the periphery. The plurality of filters 363b are band-pass filters that extract light of mutually different predetermined wavelengths from white light. In the light irradiation section 31b, a part of the white light emitted from the white light output section 312 is guided to the filter plate 361b by the half mirror 364b. The plate rotation mechanism 362b rotates the filter plate 361b to place one filter 363b among 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.

In the inspection apparatus 1b, in accordance with the type of resin that forms the insulating layer 95 (refer to Fig. 4) of the substrate 9 to be inspected, excitation light of a wavelength that causes fluorescence in the resin is extracted from white light. 363b is disposed on the optical path. That is, the filter 363b is an excitation light emitting unit for emitting 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 reflects light in a wavelength range of less than or equal to the longest wavelength among the excitation light from the plurality of filters 363b, It is configured to transmit light. Accordingly, the excitation light from the filter 363b is reflected by the dichroic mirror 323 and guided to the substrate 9 . Thereby, excitation light of a wavelength suitable for the substrate 9 to be inspected is irradiated onto the region to be inspected on the substrate 9 .

Thus, in the inspection apparatus 1b, the light irradiation part 31b is equipped with the wavelength conversion part 36b which switches the wavelength of the excitation light between several wavelengths. Thereby, since the wavelength of excitation light can be switched according to the kind of resin which forms the insulating layer 95, in the test|inspection apparatus 1b, the test|inspection of several types of board|substrates 9 can be performed. That is, the versatility of the inspection apparatus 1b can be improved.

The inspection apparatus 1c shown in FIG. 19 is provided with the structure substantially the same as the inspection apparatus 1 shown in FIG. 1 except the point that the light irradiation part 31c is equipped with the wavelength conversion part 36c. In the following description, the code|symbol same as the structure corresponding to the inspection apparatus 1 is attached|subjected to each structure of the inspection apparatus 1c.

The wavelength conversion unit 36c includes a spectrometer 365c, a slit 366c, and a spectrometer rotation mechanism 367c. The spectrometer 365c is an optical element that disperses (that is, splits) 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 output unit 312 is guided to the spectrometer 365c by the half mirror 364c and the mirror 369c. The slit 366c has an opening through which only light emitted from the spectrometer 365c in a predetermined direction (ie, light of a predetermined wavelength) passes as excitation light. The spectrometer rotation mechanism 367c changes the wavelength of light directed from the spectrometer 365c to the opening of the slit 366c by rotating the spectrometer 365c. The spectrometer rotation mechanism 367c is, for example, an electric motor.

In the inspection apparatus 1c, in accordance with the type of resin that forms the insulating layer 95 (refer to FIG. 4) of the substrate 9 to be inspected, excitation light of a wavelength that causes the resin to fluoresce is emitted from the slit 366c. It is guided to a dichroic mirror 323 . That is, the spectrometer 365c and the slit 366c are excitation light emitting units for emitting excitation light. The excitation light is reflected by the dichroic mirror 323 and guided to the substrate 9 . Thereby, excitation light of a wavelength suitable for the substrate 9 to be inspected is irradiated onto the region to be inspected on the substrate 9 . In addition, the spectrometer 365c may be another optical element, such as a grating (ie, a diffraction grating).

Thus, in the inspection apparatus 1c, the light irradiation part 31c is equipped with the wavelength conversion part 36c which switches the wavelength of the excitation light between several wavelengths. Thereby, since the wavelength of excitation light can be switched according to the kind of resin which forms the insulating layer 95, in the test|inspection apparatus 1c, the test|inspection of several types of board|substrates 9 can be performed. That is, the versatility of the inspection apparatus 1c can be improved.

In the above-mentioned inspection apparatus 1, 1a - 1c, a various change is possible.

For example, the structure of the substrate 9 inspected by the inspection apparatuses 1 and 1a to 1c is limited to that in which the insulating layer 95 is exposed around the via hole 93 as described above. It is not, and may be changed in various ways.

The structure of the wavelength conversion parts 36a-36c is not limited to what is illustrated by FIGS. 17-19, You may change variously. In addition, the wavelength conversion parts 36a-36c may be abbreviate|omitted.

In the inspection apparatus 1, the excitation light and the white light do not necessarily need to be able to be irradiated at the same time. In addition, in the inspection apparatus 1, in the case where white light is not used for inspection of the board|substrate 9, the white light output part 312 may be abbreviate|omitted. The same applies to the inspection apparatus 1a.

The above-described pinhole mirror 327 is not necessarily formed, and a half mirror or the like may be formed instead of the pinhole mirror 327 .

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 have to be formed. . The same applies to the inspection apparatuses 1a to 1c.

In the inspection apparatuses 1, 1a to 1c, instead of the dichroic mirror 323, another filter unit may be formed to separate the excitation light and light in a wavelength band different from the excitation light and guide it to the spectroscopic measuring unit 33. . In addition, the said filter part may be abbreviate|omitted.

In the inspection apparatuses 1 and 1a to 1c, for example, the head moving mechanism 23 is omitted, and the stage 21 is moved in two horizontal directions (for example, the left-right direction in FIG. 1 and the sheet of FIG. 1 ). A stage moving mechanism that is movable relative to the head 3 in a direction perpendicular to ) may be provided.

The configurations in the above embodiment and each modification may be appropriately combined as long as they do not contradict each other.

Although the invention has been described and described in detail, the foregoing description is illustrative and not restrictive. Therefore, it can be said that many modifications and aspects are possible without departing from the scope of the present invention.

1, 1a to 1c; inspection device
9 ; Board
31, 31a to 31c; light irradiator
33 ; spectral measurement unit
34 ; imaging unit
36a to 36c; Wavelength converter
93 ; via hall
94a, 94b; wiring layer
95 ; insulating layer
107; display
311 ; excitation light
312; white light output
313 ; band pass filter
323 ; dichroic mirror
327 ; pin hole mirror
327a; pin hole
S11 to S17; step

Claims (8)

An inspection device for inspecting a via hole in a substrate, comprising:
a light irradiator for irradiating excitation light for generating fluorescence in the resin forming the insulating layer to a region to be inspected including a via hole on a laminated substrate in which wiring layers and insulating layers are alternately laminated;
and a spectral measurement unit for receiving reflected light from the area to be inspected and acquiring a reflection spectrum. The method of claim 1,
and a filter unit disposed on an optical path from the region to be inspected toward the spectral measuring unit and further comprising a filter unit for guiding light of a wavelength band different from the excitation light to the spectroscopic measuring unit. The method of claim 1,
an imaging unit that receives the reflected light from the inspection target region to acquire an inspection target image that is an image of the inspection target region;
and a display unit for displaying the image to be inspected acquired by the imaging unit and the reflection spectrum acquired by the spectroscopic measurement unit. 4. The method of claim 3,
Further comprising a pinhole mirror disposed on an optical path from the inspection target area toward the spectroscopic measurement unit,
The spectral measurement unit receives light that has passed through the pinhole of the pinhole mirror among the reflected light from the area to be inspected,
and the imaging unit receives light reflected by the pinhole mirror among the light reflected from the area to be inspected. The method of claim 1,
The light irradiation unit,
an excitation light emitting unit for emitting the excitation light toward the area to be inspected;
and a white light emitting unit emitting white light toward the area to be inspected. 6. The method of claim 5,
and the light irradiation unit is capable of simultaneously irradiating the excitation light from the excitation light emitting unit and the white light from the white light emitting unit to the area to be inspected. 7. The method according to any one of claims 1 to 6,
The said light irradiation part is provided with the wavelength conversion part which switches the wavelength of the said excitation light among a plurality of wavelengths, The inspection apparatus. An inspection method for inspecting a via hole in a substrate, comprising:
a) a step of irradiating an excitation light for generating fluorescence to a resin forming the insulating layer with respect to a region to be inspected including a via hole on a laminated substrate in which wiring layers and insulating layers are alternately laminated;
b) receiving the reflected light from the area to be inspected to obtain a reflection spectrum;
c) an inspection method comprising the step of inspecting the via hole based on the reflection spectrum.

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