JPH09236415A - Method and device for detecting pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect various kinds of patterns on a base board by enabling them to be directly or indirectly divided corresponding to the kinds thereof. SOLUTION: For example, a fluorescent generation characteristic pattern image can be detected by a fluorescent illumination/detection optical system 20, a polarization elimination characteristic pattern image can be by a near infrared polarization illumination/detection optical system 60 and a red wave length light reflection characteristic pattern image can be by a diagonal red illumination/detection optical system (including a red light source 90). Under the above condition, one of the three kinds of pattern images is indirectly detected from the other two pattern images.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a circuit pattern layer,
When at least one of the pattern layers of the print pattern layers is formed as a laminated structure on the printed board, each pattern layer corresponding pattern image formed on the printed board corresponds to the pattern layer later. The pattern image corresponding to the pattern layer where the pattern image cannot be directly detected so that the pattern inspection is possible according to the inspection standard is more indirect than the pattern image corresponding to the pattern layer where the pattern image is directly detectable. Related to the pattern detection method and its apparatus, which are allowed to be detected in particular, especially for pattern defects in the conductor pattern and resist pattern formed on the printed circuit board, and for checking the position at the time of inserting / mounting components. Characters printed on /
The present invention relates to a pattern detection method and apparatus suitable for detecting a defect in a guide line pattern.

[0002]

2. Description of the Related Art Up to now, a pattern has been detected from a pattern detection target, and the quality of the pattern has been inspected by comparison with a reference pattern. There are relatively few types of patterns to be performed, and only limited types of patterns can be detected and inspected. A plane as a pattern detection target and a cross section taken along the line AA ′ are shown in FIGS. 14A and 14B respectively as an example. As can be seen from the above, the conductor pattern 2 is formed on the printed circuit board (resin substrate, ceramic substrate, etc.) as the pattern detection target, but up to now, the pattern to be detected / inspected has been The conductor pattern 2 is exclusively used, and the quality of the conductor pattern 2 is inspected by comparison with the setting reference pattern. As described above, the shape inspection is performed exclusively on the conductor pattern formed on the substrate. Generally, the shape inspection needs to be performed in an intermediate step in the board stacking step. Has become. This is because it is generally difficult to detect only the conductor pattern in a good condition when the conductor pattern and a pattern other than the conductor pattern are mixedly formed. In FIG. 14B, reference numeral 2B indicates an interlayer coupling conductor.

A method of detecting a pattern from a pattern detection target is described in, for example, a paper "Image Detection Using Fluorescence and Its Application" (Presentation Society of Japan, 56/8/1990). As described above, detection methods such as a reflected light detection method, a fluorescence detection method, and a diffused light detection method have been known so far. The reflected light detection method here is to detect the reflected illumination light from the sample by the combination of the one-dimensional / two-dimensional imaging means and the sample moving means in a state where the sample as the inspection object is irradiated with the illumination light. This method is used for detecting the reflected light, and for example, when a conductor pattern is formed on the substrate, the substrate portion (base material portion)
The conductor pattern can be detected based on the difference in reflectance between the conductor pattern and the conductor pattern. Further, the fluorescence detection method utilizes the fluorescence generation characteristic of the organic material, and when the sample on which the conductor pattern is formed is irradiated with ultraviolet light, it is generated only from the substrate portion having the fluorescence generation characteristic. This is a method of detecting fluorescence by a combination of a one-dimensional / two-dimensional imaging means and a sample moving means, and a pattern other than the substrate part pattern, that is, a conductor pattern can be detected by detecting the substrate part pattern. It has become a thing. Further, the diffused light detection method is a method of detecting a light diffusion effect on the substrate by a combination of a one-dimensional / two-dimensional imaging means and a sample moving means in a state where a slit light or the like is applied to a specific position on the substrate. Therefore, the conductor pattern is also detectable by this diffused light detection method.

[0004]

By the way, in the printed circuit industry, particularly in the manufacture of the printed wiring board, the final step, that is, the final appearance inspection of the finished substrate is performed by visual inspection. Is. This is because various patterns are formed intricately on the completed board, and therefore, there is no automatic visual inspection method / apparatus that fully satisfies the final visual inspection specifications. Currently, human visual inspection ability and flexibility are present. Because I have to rely on. Here, the completed substrate will be described by referring to a plane as an example in FIG. 13A, and lines AA 'and BB' in FIGS. 13B and 13C, respectively. As shown in the cross section of the line, the conductor pattern 2, the solder resist pattern 3, the silk printing pattern 4, and the like are formed on the substrate 1 in multiple layers.
These patterns are complicatedly formed as multi-valued (shade or gradation) multilayer patterns, and their hues are not uniform (for example, the base material may be green, and the silk print may be white (yellow in some cases). ), In particular, the solder resist is formed as a semi-transparent pattern), which is cited as the main factor inhibiting the final automatic visual inspection.

More specifically, a variety of defects such as copper pattern defects, resist portion defects, silk printing defects, foreign matter adhesion, and flaws / chips on the base material are generated from the completed substrate, which is generally a multilayer structure. -It is necessary to detect a defect as a discriminated state, but since the manufacturing process and specifications for each of these patterns are different, the inspection specifications for each of these patterns are also different. Therefore, at the time of inspection, it is necessary to perform the inspection in a state in which the patterns are separated for each layer, but each of the pattern detection methods according to the related art has a limit in performing the inspection. Is. For example, in the case of the reflected light detection method, apart from the influence of the surface condition (oxidation of the conductor pattern, etc.), the amount of reflected light in each of the conductor pattern and the silk printing pattern is almost the same, so the detected multi-value image It is impossible to separate these patterns from each other. Further, in the case of the fluorescence detection method, since the amount of fluorescence generated from each of the solder resist, the base material portion, and the silk printing pattern is the same, it is not possible to separate these patterns from the detected multi-valued image. It is impossible. Furthermore, the diffused light detection method utilizes the fact that the base material part and the conductor pattern are light diffusive and non-light diffusive, respectively, but this is applied to a completed substrate in which various pattern materials are mixed. Even in this case, the patterns cannot be separated from each other like the reflected light detection method and the fluorescence detection method. Therefore, even if various pattern information formed on the completed substrate are collectively detected and an image comparison is performed with the set reference pattern in order to perform an automatic visual inspection on the completed substrate, the pattern comparison is performed. The inspection specifications for each cannot be individually supported, and as a result, the types of defects and defects cannot be identified and discriminated, and false alarms or false detections occur frequently.
However, in the general electronic equipment, due to downsizing tendency, high functionality and high density, demands for improvement of inspection quality will become increasingly strict, but it will be difficult to secure skilled inspection personnel. Considering
It is clear that automation of the final visual inspection on the finished substrate is essential.

Therefore, an object of the present invention is to directly and indirectly correspond various types of patterns to each other even if the patterns of various types are formed as a multi-layer structure on a printed circuit board without being affected by the type. The present invention provides a pattern detection method and an apparatus therefor capable of detecting mutually separable.

[0007]

SUMMARY OF THE INVENTION Basically, the above-mentioned object is generated from a fluorescence generation characteristic pattern layer, for example, in a state where excitation light as monochromatic light having a shorter wavelength than the vertical direction is irradiated to a printed circuit board surface. The fluorescent emission characteristic pattern image based on the long-wavelength side fluorescent light and the linearly polarized illumination light set in a wavelength band different from the wavelength of the fluorescent light are radiated from the vertical / oblique direction to the printed circuit board surface, A depolarization characteristic pattern image based on reflected light in a polarization direction orthogonal to the polarization direction of the linearly polarized illumination light from the depolarization characteristic pattern layer, the linearly polarized illumination light, and the fluorescent light are set to different wavelength bands. In the state where the red wavelength illumination light is radiated obliquely to the printed circuit board surface, the red wavelength light reflection characteristic based on the red wavelength light reflected from the pattern layer is reflected. When the pattern image is directly to the detection-friendly as the pattern image, among these 3 types of pattern images is by at least one 2 type of pattern image is detected directly. Further, as the device configuration, basically, the excitation light irradiation means and the fluorescence detection means, so that the fluorescence emission characteristic pattern image can be detected,
Further, in order to make the depolarization characteristic pattern image detectable, the linearly polarized light irradiation means and the polarization detection means, and further, to make the red wavelength light reflection characteristic pattern image detectable, the red wavelength illumination light irradiation means and the red wavelength illumination light irradiation means. When the wavelength light detecting means can be installed as a constituent element, respectively, at least any two of the three types of pattern images can be directly detected. Is achieved in.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. First, the first embodiment will be described below with reference to FIGS. 1 to 5.
That is, it is a pattern detection object according to the present invention, and this is a printed board on which various kinds of patterns are formed, for example, the completed board shown in FIG. 13 described above. On the completed substrate, the solder resist pattern is formed as a photosensitive resin, the conductor pattern is formed as a copper foil, and the silk printing pattern is formed as a material for depolarizing characteristics. 1 shows a configuration of an example of a pattern detection device according to the present invention, which is a detection target. As shown in the figure, the fluorescent illumination / detection optical system 20 is intended to detect the pattern formed of the photosensitive resin material, and the purpose is to detect the pattern formed of the depolarization characteristic material. The polarized illumination / detection optical system 40 is installed.

First, the fluorescent illumination / detection optical system 20 will be described. As shown in FIG.
Through a condenser lens 22 and a fluorescence excitation filter 23
Is converted into excitation light. The fluorescence excitation filter 23 has a high brightness light source 21 so that fluorescence is easily generated from the base material of the printed board 1 or the solder resist pattern 3.
2 is for limiting the wavelength of the light 31 from the light source. For example, FIG. 2 shows its spectral characteristics. It is generally called a blue filter B370, and the center wavelength at which the maximum transmittance is 370 nm is set. Yes, from wavelength 300nm to 4
Only the light with a wavelength up to 60 nm is selectively transmitted. Now, the light 32 with a limited wavelength from the fluorescence excitation filter 23 is then irradiated onto the printed circuit board 1 after the optical path is changed by the half mirror 24, so that the base material and the solder resist pattern 3, As a result of acting as excitation light for generating fluorescence from the silk print pattern 4, fluorescence is generated from the base material, the solder resist pattern 3, and the silk print pattern 4, and this fluorescence is
Light 33 mixed with reflection excitation light from the printed circuit board surface
After passing through the half mirror 24, the mirror 25
In addition to changing the optical path, the fluorescence detection filter 26 selectively separates and extracts only the fluorescence 34. The filter 26, whose spectral characteristics are shown in FIG. 3, for example, is generally called a yellow filter Y50 and selectively transmits light having a wavelength of 500 nm or more. Fluorescence 34 extracted by the filter 26
After that, by being imaged on the photoelectric conversion surface of the detector 28 via the imaging lens 27, the pattern image of the base material and the solder resist pattern 3 is detected as the analog image signal 35. The detected analog image signal 35
Is converted into a multi-valued image signal 36 by the A / D converter 29, and then input as a fluorescence emission characteristic pattern image to the image processing unit 50a in the image processing apparatus 50, and is subjected to predetermined inspection image processing. It is a thing.

The fluorescence emission characteristic pattern image 100 has the fluorescence emission characteristic because the silk printing pattern 4 itself is generally made of an organic material as shown in FIGS. 4 (a) and 4 (b). The solder resist pattern 3 is detected as a white level pattern 5, and the fluorescent conductor pattern 2 is detected as a black level pattern 6. Therefore, when the threshold value Th1 of the brightness is appropriately set for the fluorescence generation characteristic pattern image 100, the solder resist pattern 3 or the silk printing pattern 4 and the conductor pattern 2 are in a separated state in which the conductor pattern 2 is manifested. As described later, the white level pattern 5 can also be detected as a state in which the solder resist pattern 3 and the silk printing pattern 4 are separated from each other.

Next, the polarized illumination / detection optical system 40 will be described. In parallel with the detection of the fluorescence emission characteristic pattern image, the light 51 from the white light source 41 is converted into the condenser lens 42.
Is converted into linearly polarized light by the polarizing plate 43. The polarizing plate 43 is for irradiating the surface of the printed board with the illumination light 52 having an appropriate polarization plane, and the illumination light 52 from the polarizing plate 43 whose polarization plane is adjusted has the optical path at the half mirror 24. Although it is changed by 90 ° and is irradiated onto the printed circuit board, at that time, so as not to overlap with the irradiation area by the fluorescent illumination optical system,
The irradiation is performed at a position separated by a distance d.
However, if the depolarization characteristic pattern image is not detected in parallel with the detection of the fluorescence emission characteristic pattern image,
It may be irradiated at the same position. Now, when the illuminating light 52 is applied to the printed circuit board, the illuminating light 52 is reflected on the printed circuit board. The reflected light 53 passes through the half mirror 24 and then is polarized by the polarizing plate 44. Only the changed reflected light component 54 is separated and extracted. The polarization direction of the polarizing plate 44 is the illumination light 5
The two polarization directions are orthogonal to each other. The reflected light component 54 from the polarizing plate 44 is then imaged on the photoelectric conversion surface of the detector 46 via the imaging lens 45, so that the pattern image of the silk printing pattern 4 is detected as the analog image signal 55. It is what is done. The detected analog image signal 55 is the A / D converter 29.
After being converted into a multi-valued image signal 56 by the above, it is input as a depolarization characteristic pattern image to the image processing unit 50b in the image processing apparatus 50, and is subjected to predetermined inspection image processing.

Now, the depolarization characteristic pattern image 10
However, as shown in FIGS. 5 (a) and 5 (b), this means that only the silk-printed pattern 4 made of a material having a depolarization characteristic is a white level pattern 5 and other polarization planes are not disturbed. The patterns other than the silk print pattern 4 are detected as the black level pattern 6. Therefore, the depolarization characteristic pattern image 101
On the other hand, when the brightness threshold Th2 is appropriately set, only the silk-printed pattern 4 can be detected as a manifested state, and further, the fluorescence emission characteristic pattern image 1
00 already detected as the white level pattern 5, the solder resist pattern 3 and the silk printing pattern 4
Therefore, the solder resist pattern 3 can be detected as a pattern image other than the conductor pattern 2 and the silk printing pattern 4.

Incidentally, a little supplementary explanation of FIG.
As the high-intensity light source 21, an ultra-high pressure mercury lamp, a xenon lamp, or a laser oscillator (for example, an argon ion laser oscillator) is desirable as a light source. this is,
This is because those light sources include light with a wavelength having a large fluorescence excitation ability. Further, as the light source 41, in addition to the above light source,
When a white light source such as a halogen lamp is used, it is suitable for selecting light in a wavelength band that does not overlap with the wavelength band for fluorescence excitation. Further, as the detectors 28 and 46, a high-sensitivity linear sensor such as a charge coupled device (CC
When a sensor composed of D: Charge Coupled Device) is used, it is convenient to obtain a still image. When using the linear sensor, a two-dimensional image can be easily obtained by moving the stage (for mounting a printed circuit board) in a state of being synchronized with the charge accumulation period of the linear sensor.

The first embodiment has been described above.
Next, the second embodiment will be described below with reference to FIGS. 6 to 8. That is, assuming that the pattern detection target is the same as that in the first embodiment, FIG. 6 shows the configuration of another example of the pattern detection apparatus according to the present invention. As shown in the figure, a fluorescent illumination / detection optical system (basically the same configuration as the fluorescent illumination / detection optical system described in the first embodiment) 20 and a near-infrared polarized illumination / detection optical system 60 are installed. It has become a thing. Therefore, a detailed description of the fluorescent illumination / detection optical system 20 will be omitted, and the outline thereof will be briefly described. The light 31 from the high-intensity light source 21 passes through the condenser lens 22 and has the wavelength of the fluorescence excitation filter 23. By the limitation, after being converted into the excitation light, the wavelength-limited light (excitation light) 32 has its optical path changed by the half mirror 24, has a width in the y direction, and is focused in the x direction. The linear spot light in the open state is irradiated onto the printed board 1. Now, when the light 32 is applied to the printed circuit board 1, fluorescence is generated from the base material, the solder resist pattern 3, and the silk printing pattern 4, and this fluorescence is the light 33 mixed with the reflected excitation light, After passing through the half mirror 24, only the fluorescence 34 is selectively separated and extracted by the filter 26. Filter 2
The fluorescence 34 extracted by 6 is then transferred to the imaging lens 2
7. An image is formed on a photoelectric conversion surface of a detector 28 as a high-sensitivity linear sensor composed of a charge-coupled device via a near-infrared light reflecting mirror (which is called a hot mirror, which will be described later) 71. Thus, the pattern image of the base material and the solder resist pattern 3 is detected as the analog image signal 35. The analog image signal 35 is A / D
After being converted into the multi-valued image signal 36 by the converter 29,
The fluorescence generation characteristic pattern image is input to the image processing unit 50a in the image processing apparatus 50, and then the inspection image processing is performed in a predetermined manner. At that time, the high-sensitivity linear sensor is arranged in the same direction as the linear spot light, that is, as a one-dimensional sensor so that its y-axis is in the sensor longitudinal direction.

Next, the near-infrared polarized illumination / detection optical system 60 will be described. The light 61 from the light source 41 has its wavelength band limited by the near-infrared light transmission filter 47.
FIG. 7 shows the spectral characteristics of the near infrared light transmission filter 47. As shown in the figure, it is configured as a bandpass filter that selectively transmits light in the wavelength band of 750 nm to 1250 nm. Therefore, the near-infrared light 62 is obtained from the near-infrared light transmitting filter 47, and this near-infrared light 62 is further further converted by the near-infrared polarizing plate 48 into near-infrared polarized light. In addition to being converted into light 63, the condenser lens 42 and the half mirror 24
It is irradiated onto the printed circuit board 1 at an incident angle θ ₁ via At that time, the near-infrared light 62 is irradiated as a linear spot light in parallel and at a position separated by a distance d so as not to overlap the irradiation position by the fluorescent illumination system. On the other hand, if the near-infrared light 62 is irradiated onto the printed circuit board 1, the near-infrared light 62 is reflected on the printed circuit board 1, but the reflected near-infrared light 64 passes through the half mirror 24. The optical path is 90 degrees at the hot mirror 71 through the filter 26 and the condenser lens 27.
The near-infrared polarizing plate 49, which has been changed, has a polarization direction orthogonal to the polarization direction of the near-infrared polarized light 63.
Is to be incident on. In the hot mirror 71, as shown in FIG. 8, the wavelength is 400 nm to 710 nm.
Although it transmits light in the wavelength band of,
Especially as a result of reflection of light having a wavelength of 710 nm or more,
The reflected light component 65 whose polarization state has changed on the printed circuit board 1
Only the image of the depolarization characteristic pattern is detected as the analog image signal 55 by forming an image on the photoelectric conversion surface of the detector 46 as a high-sensitivity linear sensor including a charge-coupled device. The analog image signal 55 is A
After being converted into a multi-valued image signal 56 by the / D converter 29, it is input as a depolarization characteristic pattern image to the image processing unit 50b in the image processing apparatus 50 and is subjected to predetermined inspection image processing. is there.

Now, regarding the depolarization characteristic pattern image, this is the silk printing pattern 4 made of a material having the depolarization characteristic as in the case of the above-described first embodiment.
Only the white level pattern, and other patterns other than the silk-printed pattern 4 in which the polarization plane is not disturbed are detected as the black level pattern. Therefore, when the threshold value Th2 of brightness is appropriately set for the depolarization characteristic pattern image, only the silk printing pattern 4 can be detected as a manifested state. Each of the detectors 28 and 46 is a sensor driving device 8
The operation is controlled in synchronization with the periodic signal from 0,
Further, the irradiation position on the printed board 1 is the XY stage 8
1. When the update control is performed by the computer 83 for controlling the entire apparatus via the stage driving device 82 in synchronization with the charge accumulation period signal 84 of each of the detectors 28 and 46, it is formed on the printed circuit board 1. A two-dimensional image of the depolarization characteristic pattern can be easily obtained.

Finally, the third embodiment will be described below with reference to FIGS. 9 to 12. That is, assuming that the pattern detection target is the same as in the first and second embodiments, FIG. 9 shows a configuration of another different example of the pattern detection apparatus according to the present invention. . As shown, the fluorescent illumination / detection optical system 20 in the first embodiment and the near-infrared polarized illumination in the second embodiment.
In addition to the detection optical system 60, an oblique red illumination / detection optical system in which the irradiation incident angle on the printed circuit board 1 is set to θ ₂ is additionally installed. Among these, the fluorescence illumination / detection optical system 20 and the near-infrared polarized light illumination / detection optical system 60 are the same as those in the above-described first and second embodiments. Therefore, a description of these will be omitted, and mainly, the newly added oblique red illumination / detection optical system will be described. From the oblique red illumination system, the red light from the red light source is displayed on the printed circuit board 1. Light or red light obtained by limiting the wavelength within the wavelength band (570 nm to 750 nm) is emitted at an incident angle θ ₂ , and the red light irradiates the conductor pattern 2 formed on the printed circuit board 1. The purpose is to detect it as a manifested state. Usually, the conductor pattern 2 itself is formed as copper foil or plating when forming a wiring pattern on the printed circuit board 1, and therefore has a high reflectance over the entire wavelength band of light. The illumination light is intentionally set to red light because the material of the solder resist pattern 3 formed on the printed board 1 is generally green, which is a complementary color of red. Therefore, if the conductor pattern 2 can be detected as having a better contrast in relation to the solder resist pattern 3, the illumination light need not be limited to red light.

However, depending on the orthorhombic red illumination system, the silk printing pattern 4 can also be detected in addition to the conductor pattern 2. However, in order to detect both of these patterns as being in good condition, both patterns can be detected. Can be detected with the same brightness level. by the way,
The brightness level in pattern detection is generally determined from the surface reflectance, lens specifications / characteristics, illumination light irradiation (illumination light incident) angle θ (= θ ₂ ), etc., where the irradiation angle θ Focusing only on this, and using this as a parameter, the relationship between the brightness gradation ratio between the silk print pattern 4 and the conductor pattern 2 (= silk print pattern brightness gradation / conductor pattern brightness gradation) is shown in FIG. . As can be seen from FIG. 10, assuming that the conductor pattern is formed of copper foil, if the irradiation angle θ is set to about 50 °, both patterns can be detected with the same brightness level. ing. By considering not only the irradiation angle θ but also the surface reflectance and obtaining the data as shown in FIG. 10 in advance according to the printed circuit board as the pattern detection target, the optimum irradiation angle θ is determined from this. It can be done.

Now, the oblique red illumination / detection optical system will be described in detail with reference to FIG. 9. From a red light source (a zigzag pattern or an LED lamp array arranged in a matrix pattern is also possible) 90. Light 91
Although the irradiation position on the printed circuit board 1 is the same as the irradiation position by the fluorescent illumination optical system with the optimum irradiation angle θ ₂ , it may be irradiated at a position different from that by the fluorescent illumination optical system. is there. When irradiating at the same position, the reflected light from the surface of the printed board 1 due to the irradiation of red light follows the optical path on the fluorescence detection optical system. The red light source 90 is also a diffused light source, and the emitted light 91 is reflected by the surface of the printed circuit board 1 and then half mirror (reflection of 500 nm or less, transmission of 500 nm or more) 24.
After passing through the filter 26, the condenser lens 27, and the hot mirror 71 (transmitting light of 710 nm or less), the light is incident on the dichroic mirror 72. In the dichroic mirror 72, the wavelength of light is 590n with the threshold value of 590nm.
If it is m or less, the light is reflected, but if it is more than m, it is directly transmitted through the dichroic mirror 72. Therefore, the reflected red light is transmitted through the dichroic mirror 72 and then focused on the photoelectric conversion surface of the detector 28 as a high-sensitivity linear sensor, while the fluorescence has its optical path changed by 90 ° by the dichroic mirror 72. An image is formed on the photoelectric conversion surface of the detector 73 as a linear sensor. Now, regarding the analog image signal 55 detected by the detector 28, this is the A / D
After being converted into the multi-valued image signal 56 by the converter 29,
The image data is input to the image processing unit 50a as a red wavelength light reflection characteristic pattern image, and then inspection image processing is performed.

The red wavelength light reflection characteristic pattern image 10
2, the red wavelength light reflection characteristic pattern image 10
As shown in FIGS. 11 (a) and 11 (b), 2 is a black level pattern 6 for the base material and the solder resist pattern 3 and a white level pattern 5 for the conductor pattern 2. At the same time, It can be seen that the silk print pattern 4 is also obtained as the white level pattern 5. This is because the color of the silk print pattern 4 itself is white.

In the pattern detecting apparatus shown in FIG. 9, a pattern image detector is provided corresponding to each of the three types of illumination / detection optical systems, and inspection image processing is performed on each detected pattern image. However, this does not apply to the detection optical system. For example, the fluorescence detection optical system and the orthorhombic red detection optical system can be switched over time. When switching and used, the dichroic mirror 72, the detector 73, and the image processing unit 50b
Etc. are unnecessary.

Incidentally, here, the separation and detection of only the conductor pattern 2 will be described. As described in the first and second embodiments, depending on the polarized illumination / detection optical system, FIG.
As shown in FIG. 11A, since the pattern image of only the silk-printed pattern 4 can be directly detected, the pattern image is temporarily stored in the image memory, and this is used as a mask image. By performing the inter-image calculation with the red wavelength light reflection characteristic pattern image 102 shown in (a), as shown in FIGS. 12 (a) and 12 (b), the pattern of only the conductor pattern 2 is provided as the output image 103. It is possible to detect images. Specifically, between the pixels corresponding to each other between the depolarization characteristic pattern image 101 and the red wavelength light reflection characteristic pattern image 102, if both pixels are at the white (“1”) level, the pixel Is replaced with the black (“1”) level, while in other cases, the pattern image of only the conductor pattern 2 is detected as the output image 103 by allocating the logical sum result between the pixels to that pixel. I will get it. However, even by the simple calculation between the fluorescence emission characteristic pattern image 100 shown in FIG. 4A and the red wavelength light reflection characteristic pattern image 102 shown in FIG. 11A, the separation detection of only the conductor pattern 2 is performed. Is possible.

[0023]

As described above, according to claims 1 to 10.
According to the method, even if various types of patterns are formed on the printed circuit board as a multi-layered structure, the patterns are detected as directly separable and directly separable from each other according to the type without being affected by the type. A possible pattern detection method and its device are obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an example of a pattern detection device according to the present invention.

FIG. 2 is a diagram showing spectral characteristics of a fluorescence excitation filter used in a fluorescence illumination optical system.

FIG. 3 is a diagram showing spectral characteristics of a fluorescence separation / extraction filter used in a fluorescence detection optical system.

4A and 4B are diagrams showing a fluorescence generation characteristic pattern image detected by a fluorescent illumination / detection optical system and a multi-valued image signal level on the line AA ′.

5 (a) and 5 (b) are diagrams showing a depolarization characteristic pattern image detected by a polarized illumination / detection optical system and a multi-valued image signal level on the line AA '.

FIG. 6 is a diagram showing a configuration of another example of the pattern detection apparatus according to the present invention.

FIG. 7 is a diagram showing a spectral characteristic of a near infrared transmission filter used in a near infrared polarized illumination system.

FIG. 8 is a diagram showing spectral characteristics of a hot mirror used in a near infrared polarization detection system.

FIG. 9 is a diagram showing a configuration of another example of the pattern detection apparatus according to the present invention.

FIG. 10 is a diagram showing a brightness gradation ratio between a silk-printed pattern and a conductor pattern with a parameter of an irradiation angle θ of red light onto the surface of a printed circuit board.

11 (a) and 11 (b) are red wavelength light reflection characteristic pattern images detected by an oblique red illumination / detection optical system and multilevel image signal levels on the line AA '. Showing

12A and 12B are views for explaining a method of separately detecting a conductor pattern.

13A to 13C are views for explaining a completed substrate on which a solder resist pattern, a conductor pattern, and a silk printing pattern are formed.

14A and 14B are views showing a plane as a pattern detection target and a cross section taken along the line AA ′ as an example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... (Printed) board, 2 ... Conductor pattern, 3 ... Solder resist pattern, 4 ... Silk printing pattern, 21 ... High-intensity light source, 24 ... Half mirror, 22 ... Fluorescence excitation filter, 26 ... Fluorescence detection filter, 29 ... AD Converter, 41
... White light source, 28, 46, 73 ... Detector, 22, 42 ...
Condenser lens, 47 ... Near infrared transmission filter, 48,
49 ... Near-infrared polarizing plate, 50 ... Image processing device, 90 ... Red light source

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masato Sasada 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock company Hitachi Information & Communication Division

Claims (10)

[Claims] 1. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection method capable of being indirectly detected from each pattern image corresponding to a layer, wherein a fluorescent emission characteristic pattern is obtained in a state where excitation light as short-wavelength monochromatic light is radiated to the printed circuit board surface from the vertical direction. Fluorescence emission characteristic pattern image based on the long wavelength side fluorescence emitted from the layer, and a straight line set in a wavelength band different from the wavelength of the fluorescence Depolarization characteristic pattern image based on reflected light in a polarization direction orthogonal to the polarization direction of the linearly polarized illumination light from the depolarization characteristic pattern layer in a state where the polarized illumination light is irradiated from the direction perpendicular to the printed circuit board surface. A pattern detection method in which and are directly detected as a pattern image. 2. Each pattern formed on a printed circuit board when at least one of the circuit pattern layer and the printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection device capable of being indirectly detected from each pattern image corresponding to a layer, the excitation light irradiation means for irradiating the surface of a printed circuit board with excitation light as monochromatic light having a shorter wavelength than the vertical direction, and the excitation light. Fluorescence detecting means for detecting, as a fluorescence generation characteristic pattern image, long wavelength side fluorescence generated from the fluorescence generation characteristic pattern layer by light, and the fluorescence Linearly polarized illumination means for irradiating the surface of the printed circuit board with the linearly polarized illumination light set in a wavelength band different from the wavelength of the linearly polarized light, and the linearly polarized illumination from the depolarization characteristic pattern layer by the linearly polarized illumination light A pattern detection device comprising at least polarization detection means for detecting reflected light in a polarization direction orthogonal to the polarization direction of light as a depolarization characteristic pattern image. 3. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection method capable of being indirectly detected from each pattern image corresponding to a layer, wherein a fluorescent emission characteristic pattern is obtained in a state where excitation light as short-wavelength monochromatic light is radiated to the printed circuit board surface from the vertical direction. Fluorescence emission characteristic pattern image based on the long wavelength side fluorescence emitted from the layer, and a straight line set in a wavelength band different from the wavelength of the fluorescence Depolarization characteristic pattern image based on reflected light in a polarization direction orthogonal to the polarization direction of the linearly polarized illumination light from the depolarization characteristic pattern layer in a state in which the polarized illumination light is irradiated obliquely to the printed circuit board surface. A pattern detection method in which and are directly detected as a pattern image. 4. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection device capable of being indirectly detected from each pattern image corresponding to a layer, the excitation light irradiation means for irradiating the surface of a printed circuit board with excitation light as monochromatic light having a shorter wavelength than the vertical direction, and the excitation light. Fluorescence detecting means for detecting, as a fluorescence generation characteristic pattern image, long wavelength side fluorescence generated from the fluorescence generation characteristic pattern layer by light, and the fluorescence Linearly polarized illumination means for irradiating the surface of the printed board with linearly polarized illumination light set in a wavelength band different from the wavelength of the linearly polarized illumination light, and the linearly polarized illumination from the depolarization characteristic pattern layer by the linearly polarized illumination light. A pattern detection device comprising at least polarization detection means for detecting reflected light in a polarization direction orthogonal to the polarization direction of light as a depolarization characteristic pattern image. 5. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection method that is indirectly detectable from each pattern image corresponding to a layer, and in a state in which the red wavelength illumination light is obliquely applied to the printed circuit board surface, the red wavelength light reflection characteristic pattern layer The red wavelength light reflection characteristic pattern image based on the reflected red wavelength light and the wavelength band of the red wavelength illumination light are set to different wavelength bands. Depolarization characteristic pattern based on reflected light from the depolarization characteristic pattern layer in a polarization direction orthogonal to the polarization direction of the linearly polarized illumination light in a state where the linearly polarized illumination light is applied obliquely to the printed circuit board surface. A pattern detection method in which an image and a pattern image are directly detected. 6. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection device capable of detecting indirectly from each pattern image corresponding to a layer, which comprises a red wavelength illumination light irradiating means for radiating a red wavelength illumination light obliquely onto a printed circuit board surface, and a red wavelength light reflection. A red wavelength light detecting means for detecting the reflected red wavelength light from the characteristic pattern layer as a red wavelength light reflection characteristic pattern image; Linearly polarized light irradiating means for irradiating the printed circuit board surface with linearly polarized illumination light set in a wavelength band different from the wavelength of bright light, and the linearly polarized light from the depolarization characteristic pattern layer by the linearly polarized illumination light. Polarization detection means for detecting reflected light in a polarization direction orthogonal to the polarization direction of the illumination light as a depolarization characteristic pattern image,
A pattern detection device including at least. 7. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection method capable of being indirectly detected from each pattern image corresponding to a layer, wherein a fluorescent emission characteristic pattern is obtained in a state where excitation light as short-wavelength monochromatic light is radiated to the printed circuit board surface from the vertical direction. An image of the fluorescence emission characteristic pattern based on the long-wavelength side fluorescence emitted from the layer and a red wavelength illumination set in a wavelength band different from that of the fluorescence. In the state where bright light is obliquely applied to the printed circuit board surface, the red wavelength light reflection characteristic pattern image based on the red wavelength light reflected from the red wavelength light reflection characteristic pattern layer is directly detected as a pattern image. Pattern detection method. 8. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection device capable of being indirectly detected from each pattern image corresponding to a layer, the excitation light irradiation means for irradiating the surface of a printed circuit board with excitation light as monochromatic light having a shorter wavelength than the vertical direction, and the excitation light. Fluorescence detecting means for detecting, as a fluorescence generation characteristic pattern image, long wavelength side fluorescence generated from the fluorescence generation characteristic pattern layer by light, and the fluorescence The red wavelength illumination light irradiation means for irradiating the printed circuit board surface with the red wavelength illumination light set in a wavelength band different from the above, and the red wavelength light reflection characteristic pattern layer reflects the red wavelength light to the red wavelength light reflection. Red wavelength light detection means for detecting as a characteristic pattern image,
A pattern detection device including at least. 9. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection method capable of being indirectly detected from each pattern image corresponding to a layer, wherein a fluorescent emission characteristic pattern is obtained in a state where excitation light as short-wavelength monochromatic light is radiated to the printed circuit board surface from the vertical direction. Fluorescence emission characteristic pattern image based on the long wavelength side fluorescence emitted from the layer, and a straight line set in a wavelength band different from the wavelength of the fluorescence Depolarization characteristic pattern image based on reflected light in a polarization direction orthogonal to the polarization direction of the linearly polarized illumination light from the depolarization characteristic pattern layer in a state in which the polarized illumination light is irradiated obliquely to the printed circuit board surface. And the linearly polarized illumination light, and the red wavelength illumination light set in a wavelength band different from that of each of the above-mentioned fluorescent light is obliquely applied to the surface of the printed circuit board, and the reflected red light from the red wavelength light reflection characteristic pattern layer A pattern detection method in which a red wavelength light reflection characteristic pattern image based on wavelength light is directly detected as a pattern image. 10. A pattern formed on a printed circuit board when a pattern layer of at least one of a circuit pattern layer and a printed pattern layer is formed as a laminated structure on the printed circuit board. The pattern image corresponding to the pattern layer whose pattern image cannot be directly detected so that the layer corresponding pattern image can be subsequently pattern inspected by the pattern layer corresponding inspection standard is the pattern directly detectable. A pattern detection device capable of being indirectly detected from each pattern image corresponding to a layer, the excitation light irradiation means for irradiating the surface of a printed circuit board with excitation light as monochromatic light having a shorter wavelength than the vertical direction, and the excitation light. Fluorescence detecting means for detecting, as a fluorescence emission characteristic pattern image, long-wavelength side fluorescence emitted from the fluorescence emission characteristic pattern layer by light, Linearly polarized light irradiating means for irradiating the surface of the printed board with linearly polarized illumination light set in a wavelength band different from the wavelength of light, and the linearly polarized light from the depolarization characteristic pattern layer by the linearly polarized illumination light. Polarization detection means for detecting reflected light in a polarization direction orthogonal to the polarization direction of the illumination light as a depolarization characteristic pattern image, the linearly polarized illumination light, and the red wavelength illumination light set in a wavelength band different from each of the fluorescences A red wavelength illumination light irradiation means for irradiating the printed circuit board surface from an oblique direction, and a red wavelength light detection means for detecting reflected red wavelength light from the red wavelength light reflection characteristic pattern layer as a red wavelength light reflection characteristic pattern image, A pattern detection device including at least.