JP2006078263A - Wiring pattern inspecting apparatus and wiring pattern inspecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring pattern inspecting apparatus for reducing the frequency of replacing an optical member. <P>SOLUTION: The wiring pattern inspecting apparatus, optically inspecting a wiring pattern on a top layer of a workpiece 21, comprises a semiconductor package multilayer wiring board having the wiring pattern on a light-transmitting base film. Infrared components in the light emitted from a light source 10 is blocked by a heat-ray blocking filter 12. A band-pass filter 14 selects a wavelength range from a wavelength range of the light having a blocked infrared components so as to maximize the difference between the quantity of the light reflected by the top layer wiring pattern and the quantity of the light reflected by the base film and the wiring pattern. A polarization beam splitter 18 extracts a first linear polarization, having an electric field vector direction orthogonal to the light guided direction from the light in the selected wavelength range, and guides it to a λ/4 plate 20. The λ/4 plate 20 converts the first linearly polarized light into a circularly polarized light, and makes the workpiece 21 irradiated with it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the multilayer wiring board for a semiconductor package in which a plurality of wiring patterns are laminated by a plurality of layers having transparency such as a polyimide insulating layer, the present invention optically extracts the uppermost layer wiring pattern, The present invention relates to a wiring pattern inspection apparatus and an inspection method that perform imaging with resolution and automatically inspect the pattern.

  In general, wiring patterns formed on multilayer wiring boards for semiconductor packages, which are used for the purpose of reducing the size and weight of electrical equipment, are obtained by laminating a copper foil on a polyimide film with an adhesive, and then subtracting or semi-additively. The thickness is 5 to 15 μm and the width is about 10 μm at the most integrated part.

  In this patterning process, there is a possibility that serious defects such as thinning (chips), disconnection, short circuit, and thickening (projections) of the wiring pattern may occur. For this reason, conventionally, the presence or absence of these defects has been determined by open / short continuity inspection and visual inspection. However, the visual inspection requires pattern miniaturization and skill, and the inspection results may vary depending on the physical condition of the inspector. Therefore, various automatic inspection apparatuses that automatically inspect for defects using a camera have been proposed recently. In addition, it is possible to visually inspect various defects existing in a wiring pattern having a minimum width of 10 μm in the multilayer wiring board for semiconductor packages. However, the visual inspection takes time to inspect, and the product cost increases due to an increase in labor costs. Since there is a concern, automatic inspection is necessary. For example, in order to detect a defect of 1/3 or more within a width of 10 μm, an imaging resolution of 1 μm must be realized. Therefore, it is necessary to search for an imaging method and an inspection method globally from the relationship between the imaging resolution and the imaging field of view (target work size).

  As an invention made based on such circumstances, there is an invention of Patent Document 1. FIG. 8 is a configuration diagram of an apparatus disclosed in Patent Document 1. In FIG. For example, when light is emitted from a light source 10 using high-intensity illumination that emits light over the entire visible range, such as a white light source or a metal halide lamp, the light is emitted from the light guide 11, the condenser lens 40, and the heat ray cut filter 12. Then, the light enters the polarization beam splitter 31. The heat ray cut filter 12 blocks light on the long wavelength side (for example, a wavelength of 700 nm or more) and makes other light incident on the polarization beam splitter 31.

  The light emitted from the light source 10 is so-called random light having various light components. When this random light enters the polarizing beam splitter 31, linearly polarized light is extracted by the polarizing beam splitter 31. The polarization beam splitter 31 guides the extracted linearly polarized light to the polarization beam splitter 32.

  The polarization beam splitter 32 excludes the light guided by the polarization beam splitter 31 that has an electric field vector other than the front and back directions of the paper surface, and further guides the light downward in the paper surface. The imaging lens 33 and the polarization filter 34 convert the linearly polarized light into light having an angle component with a rotation angle of 40 to 50 °, and irradiate the light toward the work 51 fixed by the work fixing drive mechanism 50. . At this time, the light component obtained by vector decomposition of the incident linearly polarized light according to the rotation angle is irradiated toward the work 51.

  The light component irradiated to the work 51 is reflected by the work 51, and the light component obtained by vector-decomposing the reflected light according to the rotation angle of the polarizing filter 34 passes through the polarizing filter 34 and the imaging lens 33, and the polarizing beam splitter. 32 is incident. At this time, linearly polarized light having an electric field vector direction in the light guide direction is extracted in the polarization beam splitter 32, and this linearly polarized light is incident on the bandpass filter 42.

  The band pass filter 42 extracts a wavelength region in which the difference between the reflected light amount of the uppermost wiring pattern and the amount from the polarization beam splitter 32 due to the reflected light of the polyimide insulating layer portion is the largest, and only the light in the extracted wavelength region is extracted. Is incident on the CCD element 41 in the sensor camera 30.

  Then, the light passing through the band pass filter 42 is imaged by the CCD element 41. The intensity of the light component reflected from the work 51 depends on copper and polyimide, and since copper has a higher reflection intensity, the uppermost copper pattern portion is imaged brightly. Moreover, when irradiating the work 51, the image of the uppermost layer wiring pattern is captured more clearly by increasing the polarization ratio and irradiating the wiring pattern and the polyimide insulating layer.

By such an invention of Patent Document 1, it becomes possible to optically remove the influence of the inner layer wiring pattern on the multilayer wiring substrate for semiconductor packages, and a high-definition image of the uppermost layer wiring pattern is picked up. Wiring patterns can be inspected automatically and with high reliability. Further, the inspection and detection of the uppermost layer wiring pattern can be performed in a short time even for the uppermost layer wiring pattern having a large area.
International Publication Number WO 2004/040281 A1

  However, such a conventional wiring pattern inspection apparatus has the following problems.

  That is, for example, the light source 10 that emits light over the entire visible light region such as a white light source or a metal halide lamp also includes some ultraviolet component.

  Among the optical members shown in FIG. 8, the bandpass filter 42 has an action of cutting ultraviolet rays, but the other optical members have no action of cutting ultraviolet rays. Therefore, the light guide 11, the condensing lens 40, the heat ray cut filter 12, the polarizing beam splitter 31, the polarizing beam splitter 32, the imaging lens 33, and the polarizing filter 34, which are optical members up to the CCD element 41, are made of ultraviolet rays. Will be irradiated. In particular, the polarization beam splitter 31, the polarization beam splitter 32, and the polarization filter 34 have low ultraviolet resistance.

  For this reason, in the wiring pattern inspection apparatus having the configuration as in Patent Document 1, in particular, the polarizing beam splitter 31, the polarizing beam splitter 32, and the polarizing filter 34 are damaged by ultraviolet irradiation, and need to be frequently replaced. There is a problem of end. This increases the running cost.

  The present invention has been made in view of such circumstances, and a bandpass filter having an action of cutting ultraviolet rays is provided on the light source side as much as possible, and the optical member is reduced by reducing the amount of ultraviolet rays that irradiate the optical member. It is an object of the present invention to provide a wiring pattern inspection apparatus and a wiring pattern inspection method capable of reducing the frequency of replacement of optical members and suppressing an increase in running cost.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the invention of claim 1 is a wiring pattern inspection apparatus for optically inspecting the uppermost wiring pattern of a work consisting of a multilayer wiring board for a semiconductor package having a wiring pattern on a light transmissive base film, comprising: a light source; , A parallel light guide means, an infrared ray shielding means, a selection means, a polarization beam splitter, a λ / 4 plate, and an imaging means.

  The parallel light guide means guides light from the light source substantially in parallel, and the infrared ray blocking means blocks an infrared component of the light from the light source. The selection means selects the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking means, The polarization beam splitter extracts, from the light in the wavelength range selected by the selection means, first linear polarized light whose electric field vector direction is orthogonal to the light guiding direction of the light, and the extracted first linear polarized light is The light is guided in a direction orthogonal to the light guide direction and the electric field vector direction of the first linearly polarized light. The λ / 4 plate converts the first linearly polarized light guided by the polarization beam splitter into circularly polarized light, and irradiates the workpiece with the converted circularly polarized light. In the imaging means, the first linearly polarized light extracted from the reflected light by the polarized beam splitter is transmitted through the λ / 4 plate, and the reflected light formed by reflecting the irradiated circularly polarized light by the work is guided to the polarized beam splitter. The second linearly polarized light orthogonal to is imaged.

  Therefore, in the wiring pattern inspection apparatus according to the first aspect of the present invention, the light incident on the polarizing filter, the polarizing beam splitter, and the λ / 4 plate having weak UV resistance is preliminarily banded by taking the above-described means. Ultraviolet rays are cut by the pass filter. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  According to a second aspect of the present invention, in the wiring pattern inspection apparatus according to the first aspect, instead of the λ / 4 plate, it has substantially the same refractive index as that of the optical member of the λ / 4 plate and is guided by the polarization beam splitter. The first linearly polarized light guided by the same refractive index optical plate that irradiates the work piece so as to condense the linearly polarized light of 1 on the work or the polarizing beam splitter through the polarizing plate at a predetermined angle. It can be exchanged for a polarization component extraction means for extracting a polarization component and irradiating the workpiece with the polarization component. Further, when the imaging unit replaces the λ / 4 plate with the same refractive index optical plate, the reflected light formed by reflecting the first linearly polarized light irradiated by the same refractive index optical plate with the workpiece is the same refracted. The second linearly polarized light orthogonal to the first linearly polarized light extracted from the reflected light is transmitted through the optical plate and guided to the polarizing beam splitter, and the λ / 4 plate is extracted as the polarization component. In this case, the reflected light formed by reflecting the predetermined polarization component irradiated by the polarization component extraction unit on the workpiece is subjected to vector decomposition according to the predetermined angle of the polarizing plate of the polarization component extraction unit and then polarized. The second linearly polarized light that is guided to the beam splitter and is orthogonal to the first linearly polarized light extracted from the vector decomposition component in the polarizing beam splitter is imaged.

  Therefore, in the wiring pattern inspection apparatus according to the second aspect of the present invention, by adopting the above-described means, the light incident on the polarizing filter having a low ultraviolet resistance and the polarizing beam splitter is preliminarily converted by the bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  According to a third aspect of the present invention, there is provided a wiring pattern inspection apparatus for optically inspecting an uppermost wiring pattern of a work comprising a multilayer wiring board for a semiconductor package having a wiring pattern on a light-transmitting base film, wherein the wiring pattern inspection apparatus is parallel to a light source. The light guide unit, the infrared ray blocking unit, the selection unit, the polarization beam splitter, the refractive index optical plate, and the imaging unit are provided.

  The parallel light guide means guides light from the light source substantially in parallel, and the infrared ray blocking means blocks an infrared component of the light from the light source. The selection unit selects a wavelength region where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking unit. The polarization beam splitter extracts, from the light in the wavelength range selected by the selection means, first linear polarized light whose electric field vector direction is orthogonal to the light guiding direction of the light, and the extracted first linear polarized light is The light is guided in a direction orthogonal to the light guide direction and the electric field vector direction of the first linearly polarized light. The refractive index optical plate has substantially the same refractive index as the optical member of the λ / 4 plate, and irradiates the work with the first linearly polarized light guided by the polarization beam splitter so as to be condensed on the work. In the imaging means, the reflected light formed by reflecting the irradiated first linearly polarized light by the work passes through the same refractive index optical plate and is guided to the polarization beam splitter, and is extracted from the reflected light by the polarization beam splitter. The second linearly polarized light orthogonal to the first linearly polarized light is imaged.

  Therefore, in the wiring pattern inspection apparatus according to the third aspect of the invention, by adopting the above-described means, the light incident on the polarizing filter having a low UV resistance and the polarizing beam splitter is preliminarily generated by a bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  According to a fourth aspect of the present invention, there is provided a wiring pattern inspection apparatus for optically inspecting an uppermost wiring pattern of a work comprising a multilayer wiring board for a semiconductor package having a wiring pattern on a light-transmitting base film, wherein the wiring pattern inspection apparatus is parallel to a light source. A light guide unit, an infrared ray blocking unit, a selection unit, a polarization beam splitter, a polarization component extraction unit, and an imaging unit are provided.

  The parallel light guide means guides light from the light source substantially in parallel, and the infrared ray blocking means blocks an infrared component of the light from the light source. The selection unit selects a wavelength region where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking unit. The polarization beam splitter extracts, from the light in the wavelength range selected by the selection means, first linear polarized light whose electric field vector direction is orthogonal to the light guiding direction of the light, and the extracted first linear polarized light is The light is guided in a direction orthogonal to the light guide direction and the electric field vector direction of the first linearly polarized light. The polarization component extraction unit extracts the polarization component having a predetermined angle from the first linearly polarized light guided by the polarization beam splitter through the polarization plate having a predetermined angle, and irradiates the workpiece with the polarization component. The imaging means transmits the reflected light formed by reflecting the irradiated polarized component by the work after being vector-decomposed according to a predetermined angle of the polarizing plate of the polarized light component extracting means, and is guided to the polarized beam splitter. The second linearly polarized light orthogonal to the first linearly polarized light extracted from the vector decomposition component in the splitter is imaged.

  Therefore, in the wiring pattern inspection apparatus according to the invention of claim 4, by taking the above-described means, the light incident on the polarizing plate having a low ultraviolet resistance and the polarizing beam splitter is preliminarily converted by a bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  According to a fifth aspect of the present invention, in the wiring pattern inspection apparatus according to any one of the first, third, and fourth aspects, the λ / 4 plate, the same refractive index optical plate, or the polarization component extracting means is provided. Removable.

  Therefore, in the wiring pattern inspection apparatus according to the fifth aspect of the present invention, by taking the above-described means, the λ / 4 plate, the same refractive index optical plate, or the polarization component extracting means can be freely selected according to the work. be able to.

  According to a sixth aspect of the present invention, in the wiring pattern inspection apparatus according to any one of the first to fifth aspects, the frequency component synthesized with the voltage supplied to the discharge lamp installed in the light source is imaged as noise. Noise removing means is added so as not to affect the means.

  Accordingly, in the wiring pattern inspection apparatus according to the sixth aspect of the present invention, by taking the above-described means, it is possible to prevent noise from entering the image picked up by the image pickup means, thereby improving the inspection accuracy. It becomes possible.

  The invention of claim 7 is the wiring pattern inspection apparatus according to any one of claims 1 to 6, wherein two polarizing plates and a half mirror installed in crossed Nicols are used instead of the polarizing beam splitter. Used to have the same function as a polarizing beam splitter.

  Therefore, in the wiring pattern inspection apparatus according to the seventh aspect of the invention, by taking the above-described means, two polarizing plates and half mirrors installed in crossed Nicols can be used instead of the polarizing beam splitter. can do.

  The invention according to claim 8 is a wiring pattern inspection method for optically inspecting the uppermost wiring pattern of a work composed of a multilayer wiring substrate for a semiconductor package having a wiring pattern on a light-transmitting base film, wherein the inspection is performed from a light source. Light is guided substantially in parallel, and the infrared component in the inspection light from the light source is blocked. Furthermore, from the wavelength range of the inspection light in which the infrared component is blocked, the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest is selected, and the selected wavelength range The first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the light beam in the light guide direction and the first straight line. The direction is perpendicular to the electric field vector direction of polarized light. Further, the first linearly polarized light guided by the polarization beam splitter is converted into circularly polarized light by the λ / 4 plate, and further, the converted circularly polarized light is irradiated to the work, and the irradiated circularly polarized light is reflected by the work. The reflected light is transmitted through the λ / 4 plate and guided to the polarizing beam splitter, and the second linearly polarized light orthogonal to the first linearly polarized light extracted from the reflected light in the polarizing beam splitter is imaged by the imaging means.

  Therefore, in the wiring pattern inspection method according to the eighth aspect of the present invention, the light incident on the polarizing filter, the polarizing beam splitter, and the λ / 4 plate having weak UV resistance is preliminarily banded by taking the above-described means. Ultraviolet rays are cut by the pass filter. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  A ninth aspect of the invention is the wiring pattern inspection method according to the eighth aspect of the present invention, wherein, instead of the λ / 4 plate, the optical member has substantially the same refractive index as that of the optical member of the λ / 4 plate, and is guided by the polarization beam splitter. The first linearly polarized light guided by the same refractive index optical plate that irradiates the work piece so as to condense the linearly polarized light of 1 on the work or the polarizing beam splitter through the polarizing plate at a predetermined angle. The polarized light component is extracted, and the polarized light component extraction means for irradiating the work with the polarized light component can be replaced. Further, when the imaging unit replaces the λ / 4 plate with the same refractive index optical plate, the reflected light formed by reflecting the first linearly polarized light irradiated by the same refractive index optical plate with the workpiece is the same refracted. The second linearly polarized light orthogonal to the first linearly polarized light which is transmitted through the optical plate and guided to the polarizing beam splitter and extracted from the reflected light by the polarizing beam splitter, and the λ / 4 plate is extracted as the polarization component extracting means. In other words, the reflected light formed by reflecting the polarization component irradiated by the polarization component extraction unit on the workpiece is vector-decomposed on the polarizing plate of the polarization component extraction unit according to a predetermined angle, and then the polarization beam splitter. The second linearly polarized light that is guided and orthogonal to the first linearly polarized light extracted from the vector decomposition component in the polarization beam splitter is imaged.

  Therefore, in the wiring pattern inspection method according to the ninth aspect of the present invention, by taking the above-described means, the light incident on the polarizing filter having a low ultraviolet resistance and the polarizing beam splitter is preliminarily converted by the bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  The invention of claim 10 is a wiring pattern inspection method for optically inspecting a top layer wiring pattern of a work comprising a multilayer wiring substrate for a semiconductor package having a wiring pattern on a light transmissive base film, wherein the inspection is performed from a light source. Light is guided substantially in parallel, and the infrared component in the inspection light from the light source is blocked. Furthermore, from the wavelength range of the inspection light in which the infrared component is blocked, the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest is selected, and the selected wavelength range The first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the light beam in the light guide direction and the first straight line. The direction is perpendicular to the electric field vector direction of polarized light. Furthermore, the first linearly polarized light guided by the polarizing beam splitter is irradiated onto the work so as to be condensed on the work by the same refractive index optical plate having substantially the same refractive index as that of the base film. The reflected light formed by reflecting the linearly polarized light on the workpiece is transmitted through the same refractive index optical plate and guided to the polarizing beam splitter, and the second light orthogonal to the first linearly polarized light extracted from the reflected light by the polarizing beam splitter. The linearly polarized light is imaged by the imaging means.

  Therefore, in the wiring pattern inspection method of the invention of claim 10, by taking the above-described means, the light incident on the polarizing filter having a low ultraviolet resistance and the polarizing beam splitter is preliminarily irradiated by a bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  The invention according to claim 11 is a wiring pattern inspection method for optically inspecting the uppermost wiring pattern of a work consisting of a multilayer wiring board for a semiconductor package having a wiring pattern on a light-transmitting base film, wherein the inspection is performed from a light source. Light is guided substantially in parallel, and the infrared component in the inspection light from the light source is blocked. Then, from the wavelength range of the inspection light from which the infrared component is blocked, select the wavelength range in which the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest, and the selected wavelength range The first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the light beam in the light guide direction and the first straight line. The direction is perpendicular to the electric field vector direction of polarized light. Further, the first linearly polarized light guided by the polarizing beam splitter is extracted through a polarizing plate having a predetermined angle provided in the polarizing component extraction unit, and the workpiece is irradiated with the polarized component. The reflected light obtained by reflecting the polarization component on the workpiece is vector-decomposed according to a predetermined angle of the polarizing plate of the polarization component extraction means, guided to the polarization beam splitter, and extracted from the vector decomposition component by the polarization beam splitter. The second linearly polarized light orthogonal to the first linearly polarized light is imaged by the imaging means.

  Therefore, in the wiring pattern inspection method of the invention of claim 11, by taking the above-described means, the light incident on the polarizing filter having a low UV resistance and the polarizing beam splitter is preliminarily converted by the bandpass filter. It has been cut. Therefore, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing the increase in running cost.

  According to a twelfth aspect of the present invention, in the wiring pattern inspection method according to any one of the eighth, tenth, and eleventh aspects, the λ / 4 plate, the same refractive index optical plate, or the polarization component extracting means is provided. Removable.

  Therefore, in the wiring pattern inspection method according to the twelfth aspect of the present invention, the λ / 4 plate, the same refractive index optical plate, or the polarization component extracting means can be freely selected according to the work by taking the above-described means. be able to.

  According to a thirteenth aspect of the present invention, in the wiring pattern inspection method according to any one of the eighth to twelfth aspects, the frequency component synthesized by the voltage supplied to the discharge lamp installed in the light source is imaged as noise. Remove noise that does not affect the means.

  Therefore, in the wiring pattern inspection method according to the thirteenth aspect of the present invention, by taking the above-described means, it is possible to prevent noise from entering the image picked up by the image pickup means, thereby improving the inspection accuracy. It becomes possible.

  According to a fourteenth aspect of the present invention, in the wiring pattern inspection method according to any one of the eighth to thirteenth aspects, two polarizing plates and a half mirror installed in crossed Nicols are used instead of the polarizing beam splitter. The same function as that of the polarization beam splitter is used.

  Therefore, in the wiring pattern inspection method of the invention of claim 14, by taking the above-described means, two polarizing plates and half mirrors installed in crossed Nicols are used instead of the polarizing beam splitter. can do.

  According to the present invention, a bandpass filter having an action of cutting off ultraviolet rays is provided on the light source side as much as possible, and the amount of ultraviolet rays irradiated on the optical member can be reduced.

  As described above, it is possible to achieve a long lifetime of the optical member, and thus to realize a wiring pattern inspection apparatus and a wiring pattern inspection method capable of suppressing the increase in running cost by reducing the replacement frequency of the optical member. Can do.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of a wiring pattern inspection apparatus to which the wiring pattern inspection method according to the first embodiment is applied.

  That is, the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied includes a light source 10, a light guide 11, a heat ray cut filter 12, a condenser lens group 13, a band pass filter 14, and a diffusion. The plate 15, the polarizing filter 16 (can be omitted), the condenser lens group 17, and the polarizing beam splitter 18 (two polarizing plates and half mirrors installed in crossed Nicols can be used instead of the polarizing beam splitter 18). A front lens group 19, a λ / 4 plate 20, a rear lens group 22, an imaging unit 23, and an image processing device 24. As described above, the wiring pattern inspection apparatus using the λ / 4 plate 20 is particularly suitable for inspection of a workpiece formed by laminating a wiring board prepared by laminating polyimide as a base film and copper as a wiring layer. Yes.

  The light source 10 is preferably a high-luminance illumination that emits light over the entire visible range, such as a metal halide lamp. A sufficient amount of light is necessary for imaging with high resolution. Therefore, for example, the light source 10 can be changed from a metal halide lamp with a power consumption of 250 W to a metal halide lamp with a power of 350 W, or the light guide 11 can be a spot type that can integrate light from a plurality of light sources 10 and output from one end. Is preferred.

  Further, the light source 10 is provided with a noise removing unit 25. The noise removing unit 25 is, for example, a noise removing circuit, and a frequency component of, for example, 100 Hz, which is synergized with a voltage supplied to a discharge lamp installed in the light source 10, does not affect the image sensor 23a as noise. To.

  The light emitted from such a light source 10 is so-called random light having various light components. When such random light is emitted from the light source 10, it enters the light guide 11.

  The light guide 11 guides the light from the light source 10 to the heat ray cut filter 12 in a substantially parallel manner.

  The heat ray cut filter 12 blocks light on the long wavelength side (for example, a wavelength of 700 nm or more) and guides other light, and an infrared filter is suitable.

  The condenser lens group 13 condenses the light that has passed through the heat ray cut filter 12 and guides it to the bandpass filter 14.

  The bandpass filter 14 selects a wavelength region where the difference between the reflected light amount in the uppermost wiring pattern and the base film using, for example, a polyimide insulating layer and the reflected light amount in the wiring pattern is the largest, Only light is guided to the diffusion plate 15 side. Specifically, attention is focused on a wavelength of 550 nm, which is a green component.

  The band pass filter 14 also has an action of cutting ultraviolet rays. Therefore, light in the selected wavelength region (for example, light having a green component of 550 nm) is guided to the diffusion plate 15 in a state where the ultraviolet component is efficiently cut.

  Since the light passing through the bandpass filter 14 is cut off from the ultraviolet component, the optical member installed on the downstream side of the bandpass filter 14 can avoid irradiation with ultraviolet rays. For this reason, it is preferable that the band pass filter 14 is arranged on the light source 10 side as much as possible. As shown in FIG. 1, at least upstream of the polarizing filter 16, the polarizing beam splitter 18, and the λ / 4 plate 20, which has weak UV resistance and is relatively easily deteriorated by UV irradiation (surface accuracy is deteriorated). It is preferable to arrange in. By arranging in this way, it is possible to extend the life of these optical members, thereby reducing the replacement frequency of these optical members and suppressing an increase in running cost.

  The diffusing plate 15 makes the light guided by the bandpass filter 14 enter the polarizing filter 16 after making the light intensity uniform. As the diffusion plate 15, a frost type diffusion plate having high permeability is suitable.

  The polarizing filter 16 extracts linearly polarized light (the electric field vector is the front and back direction in FIG. 1) from the light guided from the diffusion plate 15 in this way, and guides the extracted light to the condenser lens group 17. Since the light emitted from the light source 10 is random light as described above, the polarizing filter 16 extracts linearly polarized light from such random light.

  As for the polarizing filter 16, an appropriate filter is selected in consideration of an applicable wavelength range, an extinction ratio, a polarization ratio, an outer size, and the like, as in the polarizing beam splitter 18 described later. Further, in order to capture an image with a high resolution, the greater the total amount of transmitted light in the system, the greater the advantage. Therefore, for example, as the polarizing filter 16, a wire grid polarizing filter having a high transmittance is suitable.

  The condenser lens group 17 uniformly guides the linearly polarized light guided by the polarizing filter 16 and guides it to the polarizing beam splitter 18.

  The polarization beam splitter 18 further increases the proportion of linearly polarized light guided by the condenser lens group 17 and guides this linearly polarized light to the front lens group 19 disposed below.

  The front lens group 19 collects the linearly polarized light from the polarization beam splitter 18 and guides it to the λ / 4 plate 20.

  The λ / 4 plate 20 converts linearly polarized light guided from the front lens group 19 into circularly polarized light, and irradiates the work 21 with the converted circularly polarized light. Since the λ / 4 plate 20 is deteriorated by ultraviolet irradiation, the λ / 4 plate 20 is disposed so that it can be replaced with a new one.

  The circularly polarized light is reflected by the work 21 and becomes circularly polarized light whose rotation direction is reversed. This reflected light is converted into a linearly polarized light component in the horizontal direction in the figure by the λ / 4 plate 20 and further, the polarization beam splitter 18. After being transmitted, the light is guided to the rear lens group 22.

  The rear lens group 22 condenses the light guided from the polarization beam splitter 18 in this way in the imaging sensor 23a of the imaging unit 23 so as to be focused.

  The imaging sensor 23a images the light guided in this way. As a result, an image of the wiring pattern in which the uppermost layer wiring pattern information is revealed is acquired, and the acquired image data is sent to the image processing device 24.

  For example, instead of guiding the light guided from the polarization beam splitter 18 to the rear lens group 22, a half mirror necessary for branching the light guide direction, a rear lens group separate from the rear lens group 22, etc. May be arranged at appropriate positions, and the branched light may be imaged on a plurality of imaging sensors (not shown) to perform high-resolution and wide-field imaging with the plurality of imaging sensors.

  The image processing device 24 includes a personal computer, a keyboard, a mouse, a display, an image processing board, and the like (not shown). When the image data of the wiring pattern in which the uppermost wiring pattern information is made visible is sent from the imaging unit 23, the image data is displayed from the display. Further, various calculations using the displayed image data and normal design wiring pattern data, recognition processing, and comparison processing are performed, and the quality of the wiring pattern of the imaged image data is determined. The image processing device 24 also has a role of an interface for performing stage control and the like necessary for the imaging operation.

  Next, the operation of the wiring pattern inspection method and wiring pattern inspection apparatus according to the present embodiment configured as described above will be described.

  In the present embodiment, high-luminance illumination that emits light over the entire visible range, such as a metal halide lamp, is used as the light source 10. This metal halide lamp has a spectrum close to that of sunlight, and light guided in the system contains a wavelength component of around 370 nm or more. And as shown in FIG. 1, the light guide 11, the heat ray cut filter 12, the condensing lens group 13, the band pass filter 14, the diffuser plate 15, the polarizing filter 16, the condensing lens group 17, the polarizing beam splitter 18, the front lens A number of optical members such as the group 19, the λ / 4 plate 20, the rear lens group 22, and the image sensor 23a are arranged. For this reason, there is a concern about the influence of deterioration of these optical members due to ultraviolet irradiation, particularly deterioration of surface accuracy.

  FIG. 2 is an image showing the influence of deterioration of the surface accuracy of the λ / 4 plate 20 due to such ultraviolet irradiation. FIG. 2A is an interference image obtained by an interferometer with respect to a normal λ / 4 plate 20 whose surface accuracy is not deteriorated. On the other hand, FIG. 2B is an interference image obtained by an interferometer for the λ / 4 plate 20 whose surface accuracy has deteriorated due to ultraviolet irradiation.

  As shown in FIG. 2A, the straighter the stripe pattern, the better the surface accuracy. On the other hand, in the image shown in FIG. 2B, the stripe pattern is curved, and it can be confirmed that the surface accuracy is deteriorated due to the influence of ultraviolet irradiation.

  When such surface accuracy deterioration occurs, the image contrast is lowered, and an optimum inspection image cannot be obtained. Therefore, as shown in FIG. 1, the bandpass filter 14 having an action of cutting ultraviolet rays is disposed as close to the light source 10 as possible, and an optical member is not disposed between the light source 10 and the bandpass filter 14 as much as possible. By doing so, the life of the optical member can be extended, so that the replacement frequency of the optical member is reduced, and the increase in running cost can be suppressed.

  FIG. 3 shows an uppermost wiring pattern of a multilayer wiring board for a semiconductor package comprising a wiring pattern obtained by laminating a copper foil on a polyimide film with an adhesive and patterning this by a subtractive method or a semi-additive method. FIG. 4 is an image showing a case where the image is picked up by a ring illumination method which is a conventional technique, and a case where an image is picked up by a wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied.

  As shown in FIG. 3A, in the case of the conventional ring illumination method, it is understood that not only the uppermost layer wiring pattern A but also the inner layer wiring pattern C existing via the polyimide insulating layer B is imaged. . Furthermore, since the uppermost layer wiring pattern A and the inner layer wiring pattern C have the same brightness, the uppermost layer wiring pattern A and the inner layer wiring pattern C cannot be separated even by binarization processing, for example. As a result, it is difficult to discriminate which pattern is present on the upper side from the image where the uppermost layer wiring pattern A and the inner layer wiring pattern C intersect.

  On the other hand, as shown in FIG. 3B, in the case of an image picked up by the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied, the inner layer wiring pattern C is not picked up and the uppermost polyimide insulation is obtained. Only the layer B and the uppermost layer wiring pattern A disposed thereon are imaged. In addition, since the uppermost wiring pattern A is bright and the polyimide insulating layer B is dark, it is not affected by the inner wiring pattern C. For example, by using a simple image processing technique called binarization, The regions of the uppermost wiring pattern A and the polyimide insulating layer B can be classified with high accuracy.

  Then, in such a state that both areas are classified, CAD data (pattern design information) and non-defective work (work in which a wiring pattern is correctly formed) are compared with a reference master image, a feature extraction method, etc. It is possible to determine a portion having a difference as a defect.

  Furthermore, in the obtained image data, it is ideal that there is no noise component that can be an overdetection factor. Therefore, FIG. 4A shows image data obtained by using a metal halide lamp as the light source 10 and imaging under the condition where the noise removing unit 25 is not provided. Thus, when imaging was performed without providing the noise removing unit 25, occurrence of horizontal stripe noise was confirmed. In the case of this example, a white horizontal stripe occurs once in 30 lines, which is difficult to say with high-precision image data. Further, in the state where the wiring pattern is formed in an oblique direction, the intersection of the horizontal stripe noise and the wiring pattern. In this case, the phenomenon that the edge of the wiring pattern undulates is also confirmed, which becomes a false detection element and causes a problem. As a result of verifying this cause, it was found that it was caused by 100 Hz noise that was synergistic with the voltage supplied to the metal halide lamp.

  In FIG. 4, since horizontal stripe noise is difficult to understand, a description is given using a graph of luminance values. From the image data shown in FIG. 9, it can be seen that white lines exist throughout. When the white line information existing in the X-X ′ line shown in FIG. 9 is emphasized (integrated), data as shown in FIG. 10 is obtained. As shown in FIG. 10, it can be seen that bright portions (white lines) are generated at a constant period. If this noise component is present, the image quality deteriorates and the image can be seen, but the wiring pattern is wavy at the intersection of the white line and the wiring pattern. If such undulations exist, erroneous detection increases and stable pattern inspection cannot be performed. Therefore, it is indispensable to remove horizontal stripe noise.

  Therefore, the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied is provided with a noise removing unit 25 that removes the voltage noise generated at 100 Hz in a circuit manner. FIG. 4B shows image data obtained by imaging the same part as FIG. 4A obtained when such a noise removing unit 25 is provided. In this manner, by providing the noise removing unit 25, 100 Hz noise that is synergistic with the voltage supplied to the light source 10 is removed in a circuit, and it becomes possible to obtain more accurate image data.

  As described above, in the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied, the bandpass filter 14 having the function of cutting ultraviolet rays by the function as described above is provided with the light source 10 as much as possible. By providing it on the side, it is possible to reduce the amount of ultraviolet rays that irradiate the optical member, in particular, the polarizing filter 16, the polarizing beam splitter 18, and the λ / 4 plate 20. As a result, the lifetime of these optical members can be increased, and therefore the replacement frequency can be lowered to suppress an increase in running cost.

  Further, by providing the noise removal unit 25 in the light source 10, it is possible to remove 100 Hz noise that is synergistic with the voltage supplied to the discharge lamp installed in the light source 10 in a circuit, and to obtain more accurate image data. Can be obtained.

(Second Embodiment)
FIG. 5 is a block diagram showing an example of a wiring pattern inspection apparatus to which the wiring pattern inspection method according to the second embodiment is applied.

  That is, the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied includes the λ / 4 plate 20 in the wiring pattern inspection apparatus to which the wiring pattern inspection method is applied to the first embodiment shown in FIG. The refractive index optical plate 26 is replaced. Accordingly, the same parts as those in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different parts are described.

  It has been found that depending on the manufacturing method, material, and polarization characteristics of the base film material used for the multilayer wiring board for semiconductor packages, only the uppermost wiring pattern may not be optically manifested in the optical configuration of FIG. For example, for a multilayer wiring board for a semiconductor package having a wiring pattern formed by depositing copper plating, the same refractive index optical plate 26 is used instead of the λ / 4 plate 20. Only the uppermost wiring pattern can be revealed optically. Therefore, in the wiring pattern inspection apparatus according to the first embodiment shown in FIG. 1, the λ / 4 plate 20 is configured to be replaceable with the same refractive index optical plate 26, and the λ / 4 plate according to the workpiece 21. 20 or the same refractive index optical plate 26 can be selected. When the semiconductor package multilayer wiring board having the wiring pattern formed by depositing copper plating is inspected, the λ / 4 plate 20 is replaced with the same refractive index optical plate 26.

  The refractive index optical plate 26 has substantially the same refractive index as the optical member of the λ / 4 plate 20 and irradiates the work 21 so that the linearly polarized light guided from the front lens group 19 forms an image on the work 21. . The irradiated linearly polarized light is reflected by the work 21, and the reflected light passes through the same refractive index optical plate 26, is guided to the polarizing beam splitter 18 through the front lens group 19, and is reflected by the polarizing beam splitter 18. Linearly polarized light orthogonal to this linearly polarized light is extracted from the light. The refractive index optical plate 26 is also arranged so as to be exchangeable so that it can be exchanged at the time of deterioration.

  The rear lens group 22 condenses the light guided from the polarization beam splitter 18 in this way so as to focus on the image sensor 23a.

  The imaging sensor 23a images the light collected by the rear lens group 22 in this way. As a result, an image of the wiring pattern in which the uppermost layer wiring pattern information is revealed is acquired, and the acquired image data is sent to the image processing device 24.

  Next, the operation of the wiring pattern inspection method and wiring pattern inspection apparatus according to the present embodiment configured as described above will be described.

  FIG. 6 shows an example of image data taken for the uppermost wiring pattern of a multilayer wiring board for a semiconductor package having a wiring pattern formed by depositing copper plating, and applying the wiring pattern inspection method according to the present embodiment. It is an image which shows the case where it images with the performed wiring pattern inspection apparatus.

  Thus, it can be seen that only the uppermost wiring pattern is optically manifested and imaged. In the first embodiment, as shown in FIG. 3B, the uppermost wiring pattern A was imaged brightly and the polyimide insulating layer B was imaged dark, whereas the imaged in this embodiment. On the contrary, in the image data, the uppermost wiring pattern A is dark and the polyimide insulating layer B is brightly imaged. This is because linearly polarized light having only one direction of polarization component repeats multiple reflections inside the polyimide insulation layer B, and has a polarization component in all directions, so that the polyimide insulation layer B portion is bright and the uppermost wiring pattern A Because it becomes dark.

  In this manner, it is possible to obtain a wiring pattern image in which the uppermost wiring pattern information is made obvious by simply setting an appropriate optical condition according to the material type used for the multilayer wiring board for a semiconductor package.

(Third embodiment)
FIG. 7 is a block diagram showing an example of a wiring pattern inspection apparatus to which the wiring pattern inspection method according to the third embodiment is applied.

  That is, the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the present embodiment is applied includes the λ / 4 plate 20 in the wiring pattern inspection apparatus to which the wiring pattern inspection method according to the first embodiment shown in FIG. The polarizing plate 27 is replaced by the manufacturing method, material, and polarization characteristics of the base film material used for the multilayer wiring board for a semiconductor package. Accordingly, the same parts as those in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and different parts are described.

  Although the wiring pattern inspection apparatus whose configuration is shown in FIG. 7 may be configured independently, in the wiring pattern inspection apparatus according to the first embodiment shown in FIG. The polarizing plate 27 may be configured to be replaceable, and it may be possible to select whether to use the λ / 4 plate 20 or the polarizing plate 27 according to the work 21.

  The polarizing plate 27 has a predetermined polarization angle (for example, 45 °: with respect to the vibration direction of the electric field vector of linearly polarized light), and extracts a polarization component of a predetermined angle from the linearly polarized light guided from the front lens group 19. Then, the work 21 is irradiated with this polarized component. The irradiated polarized component is reflected by the work 21, and the reflected light is vector-decomposed according to a predetermined angle of the polarizing plate 27 and then guided to the polarizing beam splitter 18 through the front lens group 19. The beam splitter 18 extracts linearly polarized light orthogonal to the linearly polarized light extracted from the vector decomposition component. The polarizing plate 27 is also arranged so as to be exchangeable so that it can be exchanged at the time of deterioration.

  The rear lens group 22 condenses the light guided from the polarization beam splitter 18 in this way so as to focus on the image sensor 23a.

  The imaging sensor 23a images the light collected by the rear lens group 22 in this way. As a result, an image of the wiring pattern in which the uppermost layer wiring pattern information is revealed is acquired, and the acquired image data is sent to the image processing device 24.

  In this manner, it is possible to obtain a wiring pattern image in which the uppermost wiring pattern information is made obvious by simply setting an appropriate optical condition according to the material type used for the multilayer wiring board for a semiconductor package.

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The block diagram which shows an example of the wiring pattern inspection apparatus to which the wiring pattern inspection method which concerns on 1st Embodiment is applied. The image which shows the influence of deterioration of the surface accuracy of a λ / 4 plate by ultraviolet irradiation. An example of the image imaged about the uppermost layer wiring pattern of the multilayer wiring board for semiconductor packages which consists of a wiring pattern which laminated the copper foil on the polyimide film with the adhesive agent. Comparative image data showing the effect of the noise removal unit. The block diagram which shows an example of the wiring pattern inspection apparatus to which the wiring pattern inspection method which concerns on 2nd Embodiment is applied. An example of the image data imaged about the uppermost layer wiring pattern of the multilayer wiring board for semiconductor packages which has the wiring pattern formed by depositing copper plating. The block diagram which shows an example of the wiring pattern inspection apparatus to which the wiring pattern inspection method which concerns on 3rd Embodiment is applied. The block diagram of the apparatus currently disclosed by patent document 1. FIG. Image data that has noise. The figure which shows the relationship between the brightness | luminance in the X-X 'part shown in FIG. 9, and a position.

Explanation of symbols

  A ... uppermost layer wiring pattern, B ... polyimide insulating layer, C ... inner layer wiring pattern, 10 ... light source, 11 ... light guide, 12 ... heat ray cut filter, 13 ... condensing lens group, 14 ... band-pass filter, 15 ... diffusion Plate: 16 ... Polarizing filter, 17 ... Condensing lens group, 18 ... Polarizing beam splitter, 19 ... Front lens group, 20 ... λ / 4 plate, 21 ... Workpiece, 22 ... Rear lens group, 23 ... Imaging unit, 23a ... Image sensor 24 ... Image processing device 25 ... Noise removal unit 26 ... Same refractive index optical plate 27 ... Polarizing plate 30 ... Sensor camera 31 ... Polarizing beam splitter 32 ... Polarizing beam splitter 33 ... Image forming lens 34 ... Polarizing filter, 40 ... Condensing lens, 41 ... CCD element, 42 ... Band pass filter, 50 ... Work fixing drive mechanism, 51 ... Work

Claims (14)

A wiring pattern inspection apparatus for optically inspecting a top layer wiring pattern of a work composed of a multilayer wiring substrate for a semiconductor package having a wiring pattern on a light-transmitting base film,
A light source;
Parallel light guide means for guiding light from the light source substantially in parallel;
Infrared blocking means for blocking an infrared component of light from the light source;
Selection for selecting the wavelength range in which the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking means Means,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the light is extracted from the light in the wavelength range selected by the selection means, and the extracted first linearly polarized light is the light guide direction. And a polarizing beam splitter that guides in a direction orthogonal to the electric field vector direction of the first linearly polarized light,
A λ / 4 plate for converting the first linearly polarized light guided by the polarizing beam splitter into circularly polarized light and irradiating the workpiece with the converted circularly polarized light;
Reflected light obtained by reflecting the circularly polarized light applied to the workpiece is reflected by the workpiece, is transmitted through the λ / 4 plate and guided to the polarizing beam splitter, and is extracted from the reflected light by the polarizing beam splitter. A wiring pattern inspection apparatus comprising: an imaging unit configured to image a second linearly polarized light orthogonal to the first linearly polarized light. In the wiring pattern inspection apparatus according to claim 1,
Instead of the λ / 4 plate, the first linearly polarized light having substantially the same refractive index as that of the optical member of the λ / 4 plate and guided by the polarization beam splitter is condensed on the workpiece. The first linearly polarized light guided by the same refractive index optical plate that irradiates the workpiece or the polarizing beam splitter is extracted through a polarizing plate having a predetermined angle, and the polarizing component is extracted. It is possible to replace the polarized light component extraction means for irradiating the workpiece,
In the case where the λ / 4 plate is replaced with the same refractive index optical plate, the image pickup means reflects the first linearly polarized light irradiated by the same refractive index optical plate by the workpiece. Is imaged with the second linearly polarized light orthogonal to the first linearly polarized light extracted from the reflected light through the same refractive index optical plate and guided to the polarizing beam splitter, When the λ / 4 plate is replaced with the polarization component extraction unit, the reflected light formed by the predetermined polarization component irradiated by the polarization component extraction unit reflected by the workpiece is reflected by the polarization component extraction unit. After vector decomposition according to a predetermined angle of the polarizing plate, the light is guided to the polarization beam splitter and is orthogonal to the first linearly polarized light extracted from the vector decomposition component in the polarization beam splitter. A wiring pattern inspection apparatus configured to image the second linearly polarized light. A wiring pattern inspection apparatus for optically inspecting a top layer wiring pattern of a work composed of a multilayer wiring substrate for a semiconductor package having a wiring pattern on a light-transmitting base film,
A light source;
Parallel light guide means for guiding light from the light source substantially in parallel;
Infrared blocking means for blocking an infrared component of light from the light source;
Selection for selecting the wavelength range in which the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking means Means,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the light is extracted from the light in the wavelength range selected by the selection means, and the extracted first linearly polarized light is the light guide direction. And a polarizing beam splitter that guides in a direction orthogonal to the electric field vector direction of the first linearly polarized light,
Same refractive index optics having the same refractive index as that of the optical member of the λ / 4 plate and irradiating the work with the first linearly polarized light guided by the polarization beam splitter so as to be condensed on the work. The board,
Reflected light formed by reflecting the irradiated first linearly polarized light by the work is transmitted through the same refractive index optical plate and guided to the polarizing beam splitter, and is extracted from the reflected light by the polarizing beam splitter. A wiring pattern inspection apparatus comprising: an imaging unit configured to image a second linearly polarized light orthogonal to the first linearly polarized light. A wiring pattern inspection apparatus for optically inspecting a top layer wiring pattern of a work composed of a multilayer wiring substrate for a semiconductor package having a wiring pattern on a light-transmitting base film,
A light source;
Parallel light guide means for guiding light from the light source substantially in parallel;
Infrared blocking means for blocking an infrared component of light from the light source;
Selection for selecting the wavelength range in which the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest from the wavelength range of the light whose infrared component is blocked by the infrared blocking means Means,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the light is extracted from the light in the wavelength range selected by the selection means, and the extracted first linearly polarized light is the light guide direction. And a polarizing beam splitter that guides in a direction orthogonal to the electric field vector direction of the first linearly polarized light,
Polarization component extraction means for extracting the first linearly polarized light guided by the polarization beam splitter through a polarizing plate having a predetermined angle to extract the polarized component having the predetermined angle, and irradiating the polarized component on the workpiece;
Reflected light formed by reflecting the irradiated polarized component by the workpiece is subjected to vector decomposition according to a predetermined angle of the polarizing plate of the polarized component extracting means, and then guided to the polarized beam splitter, and the polarized beam splitter. The wiring pattern inspection apparatus comprising: an imaging unit that images the second linearly polarized light that is orthogonal to the first linearly polarized light extracted from the vector decomposition component in FIG. In the wiring pattern inspection apparatus according to any one of claims 1, 3, and 4,
A wiring pattern inspection apparatus provided with the λ / 4 plate, the same refractive index optical plate, or the polarization component extraction means detachably. In the wiring pattern inspection apparatus according to any one of claims 1 to 5,
A wiring pattern inspection apparatus to which a noise removing unit is added so that a frequency component combined with a voltage supplied to a discharge lamp installed in the light source does not affect the imaging unit as noise. In the wiring pattern inspection apparatus according to any one of claims 1 to 6,
A wiring pattern inspection apparatus using two polarizing plates and a half mirror installed in crossed Nicols instead of the polarizing beam splitter and having the same function as the polarizing beam splitter. A wiring pattern inspection method for optically inspecting a top layer wiring pattern of a work consisting of a multilayer wiring board for a semiconductor package having a wiring pattern on a light transmissive base film,
The inspection light from the light source is guided almost in parallel,
Blocking the infrared component of the inspection light from the light source;
From the wavelength range of the inspection light in which the infrared component is blocked, select the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the selected wavelength range by the polarization beam splitter, and the extracted first linearly polarized light is Leading to a light guide direction and a direction orthogonal to the electric field vector direction of the first linearly polarized light,
The first linearly polarized light guided by the polarizing beam splitter is converted into circularly polarized light by a λ / 4 plate, and the converted circularly polarized light is irradiated onto the workpiece,
Reflected light formed by reflecting the irradiated circularly polarized light by the workpiece is transmitted through the λ / 4 plate and guided to the polarizing beam splitter, and is extracted from the reflected light by the polarizing beam splitter. The wiring pattern inspection method in which the second linearly polarized light orthogonal to the linearly polarized light is imaged by the imaging means. The wiring pattern inspection method according to claim 8,
Instead of the λ / 4 plate, the first linearly polarized light having substantially the same refractive index as that of the optical member of the λ / 4 plate and guided by the polarization beam splitter is condensed on the workpiece. The first linearly polarized light guided by the same refractive index optical plate that irradiates the workpiece or the polarizing beam splitter is extracted through a polarizing plate having a predetermined angle, and the polarizing component is extracted. It is possible to replace the polarized light component extraction means for irradiating the workpiece,
In the case where the λ / 4 plate is replaced with the same refractive index optical plate, the image pickup means reflects the first linearly polarized light irradiated by the same refractive index optical plate by the workpiece. Is imaged with the second linearly polarized light orthogonal to the first linearly polarized light extracted from the reflected light through the same refractive index optical plate and guided to the polarizing beam splitter, When the λ / 4 plate is replaced with the polarization component extraction means, the reflected light formed by the polarization component irradiated by the polarization component extraction means reflected by the workpiece is a polarizing plate of the polarization component extraction means. Second vector orthogonal to the first linearly polarized light extracted from the vector decomposed component by the polarization beam splitter after being vector decomposed according to a predetermined angle of A wiring pattern inspection method for imaging linearly polarized light. A wiring pattern inspection method for optically inspecting a top layer wiring pattern of a work consisting of a multilayer wiring board for a semiconductor package having a wiring pattern on a light transmissive base film,
The inspection light from the light source is guided almost in parallel,
Blocking the infrared component of the inspection light from the light source;
From the wavelength range of the inspection light in which the infrared component is blocked, select the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the selected wavelength range by the polarization beam splitter, and the extracted first linearly polarized light is Leading to a light guide direction and a direction orthogonal to the electric field vector direction of the first linearly polarized light,
The first linearly polarized light guided by the polarizing beam splitter is irradiated to the work so as to be condensed on the work by a refractive index optical plate having substantially the same refractive index as the base film,
Reflected light formed by reflecting the irradiated first linearly polarized light by the work is transmitted through the same refractive index optical plate and guided to the polarizing beam splitter, and is extracted from the reflected light by the polarizing beam splitter. A wiring pattern inspection method in which the second linearly polarized light orthogonal to the first linearly polarized light is imaged by an imaging means. A wiring pattern inspection method for optically inspecting a top layer wiring pattern of a work consisting of a multilayer wiring board for a semiconductor package having a wiring pattern on a light transmissive base film,
The inspection light from the light source is guided almost in parallel,
Blocking the infrared component of the inspection light from the light source;
From the wavelength range of the inspection light in which the infrared component is blocked, select the wavelength range where the difference between the reflected light amount in the uppermost wiring pattern and the reflected light amount in the base film and the wiring pattern is the largest,
A first linearly polarized light whose electric field vector direction is orthogonal to the light guide direction of the inspection light is extracted from the light in the selected wavelength range by the polarization beam splitter, and the extracted first linearly polarized light is Leading to a light guide direction and a direction orthogonal to the electric field vector direction of the first linearly polarized light,
The first linearly polarized light guided by the polarization beam splitter is extracted through a polarizing plate having a predetermined angle provided in a polarizing component extraction unit, and the workpiece is irradiated with the polarized component.
Reflected light formed by reflecting the irradiated polarized component by the workpiece is subjected to vector decomposition according to a predetermined angle of the polarizing plate of the polarized component extracting means, and then guided to the polarized beam splitter, and the polarized beam splitter. A wiring pattern inspection method in which the second linearly polarized light orthogonal to the first linearly polarized light extracted from the vector decomposition component in FIG. In the wiring pattern inspection method according to any one of claims 8, 10, and 11,
A wiring pattern inspection method comprising the λ / 4 plate, the same refractive index optical plate, or the polarization component extracting means detachably. The wiring pattern inspection method according to any one of claims 8 to 12,
A wiring pattern inspection method for removing noise so that a frequency component combined with a voltage supplied to a discharge lamp installed in the light source does not affect the imaging means as noise. In the wiring pattern inspection method according to any one of claims 8 to 13,
A wiring pattern inspection method using two polarizing plates and a half mirror installed in crossed Nicols instead of the polarizing beam splitter and having the same function as the polarizing beam splitter.

Images