JP2004138470A - Light transmissive substrate inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide light transmissive substrate inspection advantageous for accurately determining on which a foreign substance is deposited, a front or rear surface of a light transmissive substrate. <P>SOLUTION: A light transmissive substrate device 10 is equipped with a laser beam source 20, a condensing lens 35, a beam splitter 40, an aperture member 45, a spectral analyzer 50, and the like. A laser beam 25 launched from the beam source 20 includes a first laser beam having a first wavelength and a second laser beam having a second wavelength. The condensing lens 35 condenses the first laser beam to a front surface spot on a light transmissive substrate 55 while the second laser beam is caused to pass through the front surface of the substrate 55 and condensed to a rear surface spot. The first and second laser beams thus condensed are scattered by foreign substance to produce scattered light. The scattered light of the first and second laser beams is guided to the spectral analyzer 50 via the beam splitter 40. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a light-transmissive substrate inspection apparatus, and more particularly, to a light-transmissive substrate for inspecting the cleanliness of a glass substrate surface, for example, by inspecting the presence of foreign matter adhering to the glass substrate surface of a flat display. The present invention relates to an inspection device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, flat displays have been rapidly spread because they can achieve space saving and power saving as compared with CRTs, and development for supplying excellent flat displays has been actively performed.
Examples of flat displays include a liquid crystal flat display using a backlight, color filters of each primary color and liquid crystal, a plasma display that emits light of each primary color by individual discharge in each cell, and electrons into a film doped with an organic dye. An organic EL display that emits light by injecting holes is used.
[0003]
In each of the display types, a large screen of about 10 cm to 100 cm is used, and as the size of such a display increases, the size of a glass substrate used for a flat display also increases. The increase in the size of the glass substrate causes an increase in the amount of a chemical solution required for the glass substrate cleaning step and the amount of water used for rinsing.
Further, such an increase in the use amount of the chemical solution and water results in an increase in the manufacturing cost and the cost of environmental measures, so that unnecessary cleaning is preferably omitted as much as possible. Several measures have been proposed to prevent the increase.
For example, the cleaning process is simplified by performing cleaning of a large-sized glass substrate only when the glass substrate is not clean (such as when there is an adhered substance on the substrate surface). That is, if both the front surface and the back surface of the glass substrate are clean, the cleaning in the subsequent steps can be omitted.
In addition, by maintaining the cleanliness of only the processing surface such as the formation of a wiring pattern (hereinafter, simply referred to as a “pattern”) such as a pattern for a metal electrode, the yield does not decrease due to the presence of foreign matter during pattern formation. .
As a result, the requirements for minimum cleanliness are met. That is, when there is a foreign substance only on the processing surface, cleaning of only the processing surface is sufficient, and the cleaning process is simplified.
[0004]
However, a problem arises when simplifying the cleaning process by the above method. That is, when a foreign substance attached to a light-transmitting substrate such as a glass substrate or a plastic substrate formed of a light-transmitting material is inspected, foreign substances are attached to a surface (surface) to be a processed surface for a wiring pattern. In other words, it is necessary to determine whether or not foreign matter is attached to a surface (rear surface) that is not used as the opposite processing surface.
The foreign substance inspection is realized by measuring the scattered light from the foreign substance obtained by irradiating light.However, since the target substrate is transparent, the foreign substance adhering to the front side and the foreign substance adhering to the back side are similarly detected. You.
Therefore, as a method of simultaneously performing the front and back discrimination in the foreign substance inspection of the glass substrate, the following method has been proposed in which the irradiation light is inclined with respect to the front surface of the substrate so that the light passing positions on the front surface and the rear surface are different. .
[0005]
FIG. 5 is a schematic diagram showing the configuration of a conventional light-transmitting substrate inspection apparatus 1 employing the above method.
The light transmitting substrate inspection apparatus 1 includes a laser light source 3, condensing lenses 5 and 7, aperture members 9 and 11 arranged corresponding to these two lenses, and two aperture members 9 and 11. It has detectors 13 and 15 arranged correspondingly.
[0006]
According to the light-transmitting substrate inspection apparatus 1, foreign matter inspection is performed as follows.
First, after the irradiation laser light 17 emitted from the laser light source 3 is incident on the light transmitting substrate 19 at an incident angle A of a fixed angle, the light beam 23 reflected on the upper surface 21 of the light transmitting substrate 19 and the light The light is refracted by the refractive index of the transmissive substrate 19 and is separated into a light flux 27 reflected by the back surface 25 of the light transmissive substrate 19.
Utilizing at least one of the light flux 23 and the light flux 27, if the foreign matter 29, 31 exists on at least one of the front surface 21 and the rear surface 25 of the light transmitting substrate 19, the lens 5, the lens 7, and the aperture 9 The foreign matter 29 and the foreign matter 31 are detected by the detectors 13 and 15 via the aperture 11.
Also disclosed is a device for detecting air bubbles in a transparent object. However, according to this apparatus, reflected light is detected from bubbles, and foreign matter with low reflectance cannot be detected (Patent Document 1).
[0007]
[Patent Document 1]
JP-A-7-120401
[0008]
[Problems to be solved by the invention]
By the way, when performing the foreign matter inspection on the light-transmitting substrate 19 on which the pattern is formed while performing the front / back discrimination by the conventional technique, when the irradiation laser light 17 is irradiated at an angle to the light-transmitting substrate surface 21, Since scattered light or reflected light having a large light intensity from the pattern is detected, problems occur in the following points.
[0009]
The first point is that when forward scattered light, back scattered light, and light shielding from the foreign substances 29 and 31 are detected, a device required for inspection may be arranged on the optical axis of the irradiation light 17. For this reason, it is not possible to distinguish between the front and back of the foreign matter adhering surface.
The second point is that the scattered light from the foreign substance 29 is formed at an angle A with respect to the upper surface 21 of the light transmitting substrate 19 as shown in FIG. This is an obstacle to obstructing the observation of the scattered light from the foreign substance 29.
The third point is that, when the pattern is formed on the surface 21 of the light-transmitting substrate 19, when the irradiation light is obliquely incident on the surface 21 of the light-transmitting substrate 19, the scattered or reflected light becomes As a result, the foreign matter 29 is detected to be larger than it actually is, and as a result, it is difficult to accurately detect the foreign matter 29.
More specifically, the pattern has a certain width, and since this width is generally sufficiently large as compared with a foreign substance having a size of about 1 μm, reflected light and scattered light detected under the influence of the pattern are generated from the foreign substance 29. The reflected light and the scattered light are very large, and it is difficult to detect the foreign matter 29.
[0010]
The present invention has been made in view of such circumstances, and an object of the present invention is to accurately determine whether a foreign substance is attached to the front surface or the back surface of a light-transmitting substrate, and to determine whether a foreign substance adheres to the light-transmitting substrate surface. It is an object of the present invention to provide a light-transmissive substrate inspection apparatus that is advantageous in accurately detecting whether the attached foreign matter is attached to the front surface or the back surface of the substrate surface.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a light-transmitting substrate inspection device of the present invention is a light-transmitting substrate inspection device in which a front surface is formed on one side in a thickness direction and a back surface is formed on the other side. Laser light irradiating means for simultaneously emitting the first laser light and the second laser light having the second wavelength, and applying the first laser light emitted from the laser light irradiating part to the surface of the light-transmitting substrate. A condensing lens for condensing and passing the second laser light emitted from the laser light irradiating means through the front surface of the light-transmitting substrate and condensing the second laser light on the back surface; A first light emitted from the laser light irradiating means, the first light emitted from the laser light irradiating means being disposed on an optical path between the first substrate and the light transmitting substrate; , Separating from the second laser beam A beam splitter; and a spectrum analyzing unit for analyzing a light spectrum of the reflected light separated by the beam splitter, wherein the first and second laser lights guided to the light transmitting substrate by the condenser lens are provided. The optical path is configured to be perpendicular to the front and back surfaces of the light transmitting substrate.
Therefore, the first laser light is condensed on the foreign matter adhering to the surface of the light transmitting substrate, and reflected light as scattered light is generated. The second laser light is condensed on the foreign matter adhering to the back surface. Reflected light is generated as scattered light. By analyzing the light spectrum of the reflected light of the first and second laser lights, it is possible to determine which of the front surface and the back surface has the foreign matter attached.
Further, the light-transmitting substrate inspection apparatus of the present invention is an inspection apparatus for a light-transmitting substrate having a front surface formed on one side in a thickness direction and a back surface formed on the other side, and a first laser beam having a first wavelength. A laser beam irradiating unit that simultaneously emits a second laser beam having a second wavelength, and a first laser beam emitted from the laser beam irradiating unit is condensed on a surface portion of the light transmitting substrate; and A condensing lens for passing the second laser light emitted from the laser light irradiating means through the front surface of the light-transmitting substrate and condensing the second laser light on the back surface; Spectrum analyzing means for analyzing an optical spectrum of the transmitted light transmitted from the front side to the back side, and an optical path of the first and second laser lights guided to the light transmitting substrate by the condenser lens is the light transmitting Surface and Characterized in that it is configured to be perpendicular to the rear surface.
Therefore, the first laser light is condensed on the foreign matter adhering to the surface of the light transmissive substrate to generate transmitted light as scattered light, and the second laser light is condensed on the foreign matter adhering to the back surface. This generates transmitted light as scattered light. By analyzing the optical spectrum of the transmitted light of the first and second laser beams, it is possible to determine which of the front surface and the back surface has the foreign matter attached.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing a basic configuration of a light transmitting substrate inspection apparatus according to a first embodiment of the present invention.
The light-transmitting substrate inspection apparatus 10 includes a laser light source (laser light irradiation means) 20, a condenser lens 35, a beam splitter 40, an aperture member 45, a spectrum analyzer 50, and the like.
[0013]
Laser light 24 is emitted from the laser light source 20, and the laser light 24 includes a first laser light having a first wavelength and a second laser light having a second wavelength. The first wavelength and the second wavelength have different values.
As the laser light source 20, one that emits a fundamental wave of a Nd: YAG laser and its second harmonic is preferably used.
In order to simultaneously emit the first and second laser beams, it is also possible to use two laser light sources in combination and to overlap the optical axes by a beam splitter. In this case, the manufacturing cost is increased due to the complexity of the apparatus.
[0014]
The condensing lens 35 condenses the first laser light emitted from the laser light source 20 at a position 57 on the surface of the light-transmitting substrate 55, and converts the second laser light emitted from the laser light source 20 It is configured to pass through the front surface 57 of the light-transmitting substrate 55 and condense light on the back surface 59.
Further, the laser light 24 is emitted perpendicularly to the light transmitting substrate 55 from the laser light source, and the first and second laser lights guided to the light transmitting substrate by the condenser lens 35 are also the same. It is perpendicular to the front surface 57 and the back surface 59 of the light transmitting substrate 55.
The condenser lens 35 is set so as to provide the first and second laser beams with chromatic aberration equal to the thickness of the light transmitting substrate 55.
In general, two wavelengths λ₁And λ₂The focal length at₁And f₂, And the refractive index is n₁And n₂Where f₁And f₂Satisfies the following relationship.
f₁= ((N₂-1) / (n₁-1)) f₂
That is, the focal length is the refractive index n₁And n₂And the change depends on each refractive index n₁And n₂Minus 1 from each of the values.
Therefore, the focal length of the condenser lens 35 and the lens material (glass material, transparent plastic, transparent acrylic resin substrate or the like) may be selected according to the thickness of the light transmitting substrate 55. For example, when the focal length of the condenser lens 35 is set to 200 mm, when a laser light source that emits the fundamental wave of the Nd: YAG laser and its second harmonic is used, the difference in focal length due to chromatic aberration is about 5 mm. This is suitable when the light transmitting substrate 55 has a thickness of 5 mm.
[0015]
The beam splitter 40 is disposed on an optical path between the laser light source 20 and the light transmissive substrate 55, in this embodiment, on an optical path between the laser light source 20 and the condenser lens 35, It is configured to separate the reflected light 30 of the first and second laser beams on the front surface 57 and the rear surface 59 of the light transmitting substrate 55 from the first and second laser beams emitted from the laser light source 20. ing.
More specifically, the beam splitter 40 includes an optical path that transmits the first and second laser beams from the laser light source 20 and guides the first and second laser beams to the light transmitting substrate 55 through the condenser lens 35. And a light path for reflecting the reflected light 30 guided through the condenser lens 35 to guide the light to the spectrum analyzing means 50.
[0016]
The aperture member 45 has an aperture 47 having a predetermined diameter. When the reflected light 30 guided by the beam splitter 40 passes through the aperture 47, only the reflected light 30 passes, and other unnecessary light is transmitted. It is configured so as to block unnecessary light.
The spectrum analyzing means 50 is constituted by a known spectrum analyzer, and is configured to analyze the light intensity with respect to the wavelength of the reflected light 30 passing through the aperture 47, that is, the light spectrum.
[0017]
In the following, referring further to FIG. 1, it is determined whether a front surface 57 and a back surface 59 are parallel to each other and whether a foreign substance is attached to the front surface 57 and the back surface 59 of the plate-shaped light transmitting substrate 55 having a constant thickness, The operation of inspecting the cleanness of the light transmitting substrate 55 by measuring the light intensity of the scattered light from the foreign material when the foreign material is present by the spectrum analyzer 50 will be described.
First, the light-transmitting substrate 55 is disposed, and the laser light is emitted from the laser light source 20 so that the optical axes of the first and second laser lights are perpendicular to the surface of the light-transmitting substrate 55.
The emitted first and second laser beams pass through the beam splitter 40 and enter the condenser lens 35. The condensing lens 35 condenses the incident first laser light on the surface 57 of the light-transmissive substrate 55 and passes the second laser light through the surface 57 of the light-transmissive substrate 55 to form the light-transmissive substrate 55. The light is focused on 59 places on the back surface.
At this time, if any foreign matter is attached to either the front surface 57 or the back surface 59 of the transparent substrate 55, the collected first and second laser beams are scattered by the foreign material to generate scattered light, The scattered light of the first and second laser lights is condensed by the condenser lens 35 as reflected light of the first and second laser lights, and is guided to the beam splitter 40.
[0018]
The beam splitter 40 separates the first and second laser lights emitted from the laser light source 20 and the respective reflected lights guided from the condenser lens 35, and passes only the reflected light to an aperture 47. Through the spectrum analyzer 50.
The spectrum analyzer 50 analyzes the received reflected light.
Based on the analysis result, it is determined whether or not foreign matter has adhered to the front surface 57 and the back surface 59 of the transmissive substrate 55 as described below.
[0019]
Next, referring to FIG. 2, it is determined based on the measurement result of the light intensity spectrum obtained by light transmitting substrate inspection apparatus 10 that the foreign matter is attached to either front surface 57 or rear surface 59 of transparent substrate 55. The operation to be performed will be described.
FIGS. 2A and 2B are graphs showing measurement results of a light intensity spectrum when a foreign substance is attached to the front surface 57 and the back surface 59 of the light transmitting substrate 55, respectively.
In the present embodiment, the wavelength (first wavelength) of the first laser light is λ₁The wavelength (second wavelength) of the second laser light is λ₂And the first wavelength λ₁Is focused at the position of the surface 57 of the transparent substrate 55, and the second wavelength λ₂Is focused on the position of the back surface 59 of the transparent substrate 55.
[0020]
When the foreign matter has adhered to the surface 57 of the light transmitting substrate 55, the first wavelength λ₁If there is a foreign substance at the position where the first laser light is focused on the surface 57 of the transparent substrate 55, both the reflected light in the case of the transparent substrate 55 alone and the scattered light due to the foreign substance are detected by the spectrum detector 50. Is detected. Note that this scattered light is generated in a direction opposite to the traveling direction of the laser light, that is, in a backward direction, and is referred to as back scattered light.
For this reason, as shown in FIG.₁And the second wavelength λ₂When comparing the light intensity of the laser light of₁Of the laser light of the second wavelength λ₂It can be seen that the light intensity is larger than the light intensity of the laser light. As a result, in this case, it can be determined that the foreign matter is on the surface 57 of the transparent substrate 55.
[0021]
On the other hand, if foreign matter adheres to the back surface 59 of the light transmitting substrate 55 in the same manner, the wavelength λ₂If there is a foreign matter at a position where the laser light is focused on the back surface 59 of the transparent substrate 55, both the reflected light in the case of the transparent substrate 55 alone and the scattered light due to the foreign matter are detected by the spectrum detector 50. You.
For this reason, as shown in FIG.₁And the second wavelength λ₂When comparing the light intensity of the laser light of₂Is the first wavelength λ.₁It can be seen that the light intensity is larger than the light intensity of the laser light. As a result, in this case, it can be determined that the foreign matter is on the back surface 59 of the transparent substrate 55.
At this time, a slit is provided at a position directly above the transmissive substrate 55 or the like so as not to detect the scattered light other than the region to be inspected by the spectrum detector 50, or the slit is formed just above the transmissive substrate 55 or the beam splitter 40. An optical filter may be provided at a position between the device 50 and the device 50.
[0022]
As described above in detail, according to the present embodiment, the first laser light is focused on the surface 57 of the light transmitting substrate 55 by the condenser lens 35, and the second laser light is focused on the light transmitting substrate 55. The light passes through the front surface 57 of the light-transmitting substrate 55 and is focused on the back surface 59, and only the reflected light of the first and second laser beams is guided to the spectrum analyzer 50 by the beam splitter 40, and the spectrum is analyzed. By analyzing with the device 50, it is possible to accurately determine which of the front surface 57 and the back surface 59 of the light transmissive substrate 55 has the foreign matter attached thereto, and to check whether the foreign matter adhered to the light transmissive substrate surface is Irrespective of which of the front surface 57 and the back surface 59 is adhered, the detection can be performed accurately.
[0023]
Next, a second embodiment will be described.
FIG. 3 is a schematic diagram illustrating a configuration of a substrate inspection system 100 that can be used for inspection in a manufacturing process to which the light-transmissive substrate inspection device 10 according to the first embodiment is applied.
In FIG. 3, the same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
The substrate inspection system 100 includes a chamber 70, a blower 72, an air filter 74, a light-transmitting substrate entrance 76, an exhaust port 78, a personal computer 90, and the like, in addition to the light-transmitting substrate inspection device 10.
The chamber 70 has a plate-like base member 85 attached to the upper surface of the bottom wall, and an XY stage 80 is provided on the upper surface of the base member 85.
The XY stage 80 is provided so as to be movable in two directions of an X axis and a Y axis orthogonal to each other in a horizontal plane with respect to the base member 85, and the light transmitting substrate 55 is mounted on the XY stage 80. .
Further, a damper (reflection prevention mechanism) for preventing reflection of laser light is provided on the entire upper surface of the XY stage 80 facing the light transmitting substrate 55. The XY stage 80 is configured to be driven in the X-axis and Y-axis directions by drive control means (not shown).
[0024]
The blower 72 and the air filter 74 are provided on the upper wall of the chamber 70, and are configured to send the air outside the chamber 70 taken in by the blower 72 into the chamber 70 via the air filter 74.
The exhaust port 78 is provided on the bottom wall of the chamber 70, and is configured to exhaust air inside the chamber 70 to the outside. Thus, the air inside the chamber 70 is cleaned.
The light-transmitting substrate carrying-in port 76 is provided on a side wall of the chamber 70, and is configured to transfer the light-transmitting substrate 55 between the inside and the outside of the chamber 70. The transmissive substrate 55 is configured to be placed and fixed on the XY stage 80.
Inside the chamber 70, a condenser lens 35, a beam splitter 40, an aperture member 45, and a spectrum analyzer 50 that constitute the light-transmitting substrate inspection device 10 are disposed in the same manner as in the first embodiment. I have.
Outside the chamber 70, the laser light source 20 and a mirror 60 for guiding the laser light emitted from the laser light source 20 to the condenser lens 35 via the beam splitter 40 are provided.
The personal computer 90 is configured to perform data processing based on the analysis result of the optical spectrum output from the spectrum analyzer 50 and output the processing result to a display or a printer. .
The personal computer 90 is configured to control the drive control means of the XY stage 80. More specifically, the personal computer 90 previously holds the coordinate data of the XY coordinates of the light transmitting substrate 55 placed on the XY stage 80, and controls the position of the XY stage 80 based on the coordinate data. It is configured to be able to perform.
In the present embodiment, the XY stage 80, the drive control means, and the personal computer 90 constitute a moving means in the claims.
[0025]
The operation of the thus configured substrate inspection system 100 will be described.
As in the first embodiment, the laser light including the first and second laser light is emitted from the laser light source 20, thereby causing foreign matter adhering to the front surface 57 and the back surface 59 of the light-transmitting substrate 55. Backscattered light is generated.
The backscattered light is condensed by the condensing lens 35, passes through the beam splitter 40 and the aperture 47 of the aperture member 45, and is guided to the spectrum analyzer 50, where the light spectrum is analyzed.
Then, the result of the spectrum analysis is transmitted to the personal computer 90. In the personal computer 90, based on the transmitted spectrum analysis result, as shown in FIG. 2, the front surface 57 and the back surface 59 of the light transmitting substrate 55 are associated with the light spectrum of the backscattered light. Outputs the display of inspection results.
[0026]
According to such a board inspection system 100, similarly to the first embodiment, it is possible to accurately determine which of the front surface 57 and the rear surface 59 of the light-transmitting substrate 55 has a foreign substance adhered thereto. Accordingly, it is possible to accurately detect foreign matter adhering to the light-transmitting substrate surface irrespective of which surface 57 or back surface 59 of the substrate surface adheres.
Further, by controlling the XY stage 80 based on the coordinate data of the light-transmitting substrate 55 previously held by the personal computer 90, the laser light is emitted to an arbitrary position on the light-transmitting substrate 55. Can be scanned.
Further, since the laser light is irradiated so that the laser light is perpendicular to the front surface 57 and the back surface 59 of the light transmitting substrate 55, the laser light is scattered by the pattern formed on the light transmitting substrate 55. Since generation of light is suppressed, it is advantageous in preventing erroneous detection due to scattered light generated by the pattern.
In other words, the light-transmitting substrate inspection device of the present invention can also determine which surface of the light-transmitting substrate has foreign matter attached to the light-transmitting substrate on which the pattern for metal wiring is formed. The most accurate inspection possible is achieved.
[0027]
Meanwhile, the spectrum analyzer 50 reflects the backscattered light by the first and second laser beams and the reflected light on the front surface 57 and the rear surface 59 of the light transmitting substrate 55 in a state where no foreign matter is attached. And the reflected light of the first and second laser beams. In the spectrum analyzer 50, in order to improve the S / N ratio of the backscattered light, it is preferable to reduce the intensity of the reflected light of the first and second laser lights as much as possible.
In the present embodiment, a damper for preventing reflection of laser light is provided on the entire surface of the upper surface of the XY stage 80 facing the light transmitting substrate 55. The intensity of the reflected light of the first and second laser beams reflected on the front surface 57 and the back surface 59 of the conductive substrate 55 can be reduced, and therefore, it is advantageous in improving the S / N ratio of the backscattered light. It becomes.
[0028]
The light-transmitting substrate formed of a light-transmitting material such as a transparent glass plate or a transparent plastic plate used for a flat display has recently been enlarged to have a vertical or horizontal size of 1 m or more. Therefore, the cleaning process is performed for each sheet.
Therefore, since the light-transmitting substrates do not overlap with each other, it is not necessary to consider cross-contamination in which a foreign substance adhering on a certain light-transmitting substrate adheres to another light-transmitting substrate. Therefore, when the foreign matter is attached only to the back surface 59 where no pattern is formed, the cleaning step can be omitted.
That is, it is possible to rationalize the cleaning process by determining which of the front surface 57 and the rear surface 59 of the light-transmitting substrate has a foreign substance adhered by the light-transmitting substrate inspection apparatus of the present embodiment. .
Furthermore, the use of chemicals used in the cleaning process and the amount of water used for rinsing is also increasing due to the increase in the size of the light-transmitting substrate, and consequently reducing manufacturing costs and contributing to environmental measures by streamlining the cleaning process. This is advantageous.
[0029]
Next, a third embodiment will be described.
FIG. 4 is a schematic diagram showing a configuration of a substrate inspection system 200 to which the light-transmitting substrate device 10A according to the third embodiment of the present invention is applied. In FIG. 4, the same portions as those in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.
The third embodiment is different from the first and second embodiments in that the third embodiment analyzes not the light reflected from the light-transmitting substrate but the light transmitted through the light-transmitting substrate. .
The substrate inspection system 200 includes a chamber 70, a blower 72, an air filter 74, a light-transmissive substrate carry-in port 76, an exhaust port 78, a personal computer 90, and the like, in addition to the light-transmissive substrate inspection device 10A.
An XY stage 80A is provided inside the chamber 70.
The XY stage 80A is provided so as to be movable in two directions of an X axis and a Y axis orthogonal to each other in a horizontal plane, and the light transmitting substrate 55 is mounted on the XY stage 80A.
The XY stage 80A is configured such that light is transmitted through the entire area facing the light transmitting substrate 55.
The XY stage 80A is configured to be driven in the X-axis and Y-axis directions by drive control means (not shown).
[0030]
Inside the chamber 70, a condensing lens 35, a transmitted light condensing lens 36, an aperture member 45, and a spectrum analyzer 50 constituting the light transmitting substrate inspection apparatus 10A are arranged in the same manner as in the first embodiment. Is established.
Outside the chamber 70, the laser light source 20 and a mirror 60 for guiding the laser light emitted from the laser light source 20 to the condenser lens 35 via the beam splitter 40 are provided.
[0031]
Laser light 24 is emitted from the laser light source 20, and the laser light 24 includes a first laser light having a first wavelength and a second laser light having a second wavelength. The first wavelength and the second wavelength have different values.
The condensing lens 35 condenses the first laser light emitted from the laser light source 20 at a position 57 on the surface of the light-transmitting substrate 55, and converts the second laser light emitted from the laser light source 20 It is configured to pass through the front surface 57 of the light-transmitting substrate 55 and condense light on the back surface 59.
The laser light reflected by the mirror 60 is perpendicular to the surface 57 of the light transmitting substrate 55, and the first and second laser beams guided to the light transmitting substrate 55 by the condenser lens 35. Light is also perpendicular to the front surface 57 and the back surface 59 of the light transmitting substrate 55.
The condenser lens 35 is set so as to provide the first and second laser beams with chromatic aberration equal to the thickness of the light transmitting substrate 55.
[0032]
The transmitted light condensing lens 36 condenses the transmitted light transmitted from the first and second laser beams through the light transmitting substrate 55 from the front surface 57 to the back surface 59 and guides the transmitted light to the spectrum analyzing unit 50. Is formed.
The aperture member 45 has an aperture 47 having a predetermined diameter. When the transmitted light guided by the transmitted light condensing lens 36 passes through the aperture 47, the aperture member 45 allows only the transmitted light to pass therethrough. It is configured to block unnecessary light.
The spectrum analysis means 50 is constituted by a known spectrum analyzer, and is configured to analyze the light intensity with respect to the wavelength of the transmitted light passing through the aperture 47, that is, the light spectrum.
In the present embodiment, the XY stage 80, the drive control means, and the personal computer 90 constitute a moving means in the claims.
[0033]
The operation of the thus configured substrate inspection system 200 will be described.
The first and second laser beams emitted from the laser light source 20 enter the condenser lens 35 via the mirror 60. The condenser lens 35 condenses the incident first laser light on the surface 57 of the optically transparent substrate 55, and passes the second laser light through the surface 57 of the optically transparent substrate 55 to form a transparent substrate 55. The light is focused on 59 places on the back surface.
At this time, if foreign matter is attached to one of the front surface 57 and the back surface 59 of the transparent substrate 55, the collected first and second laser beams are scattered by the foreign material, and the first and second laser beams are scattered. The light is condensed by the transmitted light condensing lens 36 as transmitted light of the laser light, and is guided to the spectrum analyzer 50 via the aperture 47.
The spectrum analyzing means 50 is constituted by a known spectrum analyzer, and is configured to analyze the light intensity with respect to the wavelength of the reflected light 30 passing through the aperture 47, that is, the light spectrum.
Based on this analysis result, it is determined whether or not foreign matter has adhered to the front surface 57 and the back surface 59 of the transparent substrate 55, as described below.
[0034]
With reference to FIG. 2, a description will be given of the measurement result of the light intensity spectrum obtained by the light-transmitting substrate inspection device 10 </ b> A, and the discriminating operation of the foreign matter adhering to either the front surface 57 or the back surface 59 of the transparent substrate 55. explain.
When the foreign matter has adhered to the surface 57 of the light transmitting substrate 55, the first wavelength λ₁If there is a foreign substance at the position where the first laser light is focused on the surface 57 of the transparent substrate 55, both the transmitted light in the case of the transparent substrate 55 alone and the scattered light due to the foreign substance are detected by the spectrum detector 50. Is detected. The scattered light is called forward scattered light because it is generated toward the same side as the traveling direction of the laser light, that is, toward the front.
For this reason, as shown in FIG.₁And the second wavelength λ₂When comparing the light intensity of the laser light of₁Of the laser light of the second wavelength λ₂It can be seen that the light intensity is larger than the light intensity of the laser light. As a result, in this case, it can be determined that the foreign matter is on the surface 57 of the transparent substrate 55.
[0035]
On the other hand, if foreign matter adheres to the back surface 59 of the light transmitting substrate 55 in the same manner, the wavelength λ₂If there is a foreign substance at the position where the laser light is focused on the back surface 59 of the transparent substrate 55, both the transmitted light in the case of the transparent substrate 55 alone and the forward scattered light due to this foreign substance are detected by the spectrum detector 50. Is done.
For this reason, as shown in FIG.₁And the second wavelength λ₂When comparing the light intensity of the laser light of₂Is the first wavelength λ.₁It can be seen that the light intensity is larger than the light intensity of the laser light. As a result, in this case, it can be determined that the foreign matter is on the back surface 59 of the transparent substrate 55.
[0036]
Then, similarly to the second embodiment, the result of the spectrum analysis is transmitted to the personal computer 90. As shown in FIG. 2, the personal computer 90 correlates the front surface 57 and the back surface 59 of the light transmitting substrate 55 with the light spectrum of the forward scattered light based on the transmitted spectrum analysis result. Outputs the display of inspection results.
[0037]
As described in detail above, according to the third embodiment, the first laser light is condensed on the surface 57 of the light transmitting substrate 55 by the condensing lens 35, and the second laser light is condensed. Is passed through the front surface 57 of the light-transmitting substrate 55 and condensed at 59 places on the back surface, and the first and second laser lights are transmitted light transmitted through the light-transmitting substrate 55 from the front surface 57 to the back side. By analyzing the spectrum with the spectrum analyzer 50, it is possible to accurately determine which of the front surface 57 and the rear surface 59 of the light transmissive substrate 55 has a foreign substance attached, The attached foreign matter can be accurately detected irrespective of which of the front surface 57 and the rear surface 59 of the substrate surface is attached.
Also in the third embodiment, similarly to the second embodiment, the laser light is applied so that the laser light is perpendicular to the front surface 57 and the back surface 59 of the light transmitting substrate 55. Since irradiation is performed, generation of scattered light due to the pattern formed on the light-transmitting substrate 55 is suppressed, which is advantageous in preventing erroneous detection due to scattered light generated by the pattern. Even on a light-transmitting substrate on which a pattern for metal wiring is formed, it is possible to accurately determine on which surface of the light-transmitting substrate foreign matter is attached.
Further, similarly to the second embodiment, it is possible to rationalize the cleaning process by judging which of the front surface 57 and the back surface 59 of the light transmissive substrate has a foreign substance attached thereto. This is advantageous in reducing manufacturing costs and contributing to environmental measures.
[0038]
In each of the above-described embodiments, as the laser light, the fundamental wave of the Nd: YAG laser is used as the first laser light, and its second harmonic is used as the second laser light. A two-wavelength laser beam having the above effect may be used.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to accurately determine whether the foreign matter is attached to the front surface or the back surface of the light transmitting substrate, and to determine whether the foreign material attached to the light transmitting substrate surface It is possible to provide a light-transmissive substrate inspection apparatus that is advantageous in performing accurate detection regardless of whether it is attached to the front surface or the back surface.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a basic configuration of a light transmitting substrate inspection apparatus according to a first embodiment of the present invention.
FIG. 2 is a graph showing an example of a measurement result of a light intensity spectrum by the light transmitting substrate inspection device according to the first embodiment of the present invention.
FIG. 3 is a schematic diagram illustrating a configuration of a board inspection system 100 according to a second embodiment of the present invention.
FIG. 4 is a schematic diagram illustrating a configuration of a board inspection system 100 according to a third embodiment of the present invention.
FIG. 5 is a schematic diagram showing a basic configuration of a conventional light transmitting substrate inspection apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Light transmission board | substrate inspection apparatus, 20 ... Laser light source, 40 ... Beam splitter, 45 ... Aperture member, 50 ... Spectrum analyzer, 55 ... Light transmission board.

Claims (14)

An apparatus for inspecting a light-transmitting substrate having a front surface formed on one side in a thickness direction and a back surface formed on the other side,
Laser light irradiation means for simultaneously emitting a first laser light having a first wavelength and a second laser light having a second wavelength;
The first laser light emitted from the laser light irradiating means is focused on the surface of the light transmitting substrate, and the second laser light emitted from the laser light irradiating means is focused on the surface of the light transmitting substrate. A condenser lens that passes through and collects light on the back side,
Reflected light, which is disposed on an optical path between the laser light irradiating means and the light transmissive substrate, and wherein the first and second laser lights are reflected on a front surface and a back surface of the light transmissive substrate; A beam splitter for separating the first and second laser beams emitted from the irradiation unit,
Spectral analysis means for analyzing the optical spectrum of the reflected light separated by the beam splitter,
An optical path of the first and second laser beams guided to the light transmitting substrate by the condenser lens is configured to be perpendicular to a front surface and a rear surface of the light transmitting substrate.
A light-transmitting substrate inspection apparatus, characterized in that: The focal length of the condenser lens such that the difference between the focal length of the first laser beam by the condenser lens and the focal length of the second laser beam by the condenser lens is equal to the thickness of the light transmitting substrate. 2. The light-transmitting substrate device according to claim 1, wherein chromatic aberration is set. The reflected light analyzed by the spectrum analyzing means is a first scattered light in which a first laser beam condensed on a surface of the transparent substrate is scattered by a foreign substance attached to the surface and the transparent substrate. 2. The light-transmitting substrate inspection apparatus according to claim 1, wherein the second laser light condensed on the back surface includes second scattered light scattered by foreign matter attached to the back surface. Based on the light spectrum of the transmitted light including the first and second scattered lights analyzed by the spectrum analysis means, which of the front surface and the back surface of the transparent substrate has the foreign matter attached to? 4. The light-transmitting substrate inspection apparatus according to claim 3, wherein: An aperture means is provided on an optical path between the beam splitter and the spectrum analysis means, and the spectrum analysis means is configured to receive the reflected light via the aperture means. The light-transmitting substrate inspection device according to claim 1. The light transmitting substrate inspection apparatus according to claim 1, wherein a wiring pattern is formed on the light transmitting substrate. 2. The light transmitting substrate inspection apparatus according to claim 1, further comprising a moving unit that moves the light transmitting substrate so that an entire region or a predetermined region of the light transmitting substrate can be inspected. An apparatus for inspecting a light-transmitting substrate having a front surface formed on one side in a thickness direction and a back surface formed on the other side,
Laser light irradiation means for simultaneously emitting a first laser light having a first wavelength and a second laser light having a second wavelength;
The first laser light emitted from the laser light irradiating means is focused on the surface of the light transmitting substrate, and the second laser light emitted from the laser light irradiating means is focused on the surface of the light transmitting substrate. A condenser lens that passes through and collects light on the back side,
Spectrum analysis means for analyzing an optical spectrum of the transmitted light in which the first and second laser lights have transmitted through the light-transmitting substrate from the surface to the back side,
An optical path of the first and second laser beams guided to the light transmitting substrate by the condenser lens is configured to be perpendicular to a front surface and a rear surface of the light transmitting substrate.
A light-transmitting substrate inspection apparatus, characterized in that: The focal length of the condenser lens such that the difference between the focal length of the first laser beam by the condenser lens and the focal length of the second laser beam by the condenser lens is equal to the thickness of the light transmitting substrate. 9. The light-transmitting substrate device according to claim 8, wherein chromatic aberration is set. The transmitted light analyzed by the spectrum analyzing means is a first scattered light in which the first laser light condensed on the surface of the transparent substrate is scattered by a foreign substance attached to the surface and the transparent substrate. 9. The light-transmissive substrate inspection apparatus according to claim 8, wherein the second laser light focused on the back surface includes second scattered light scattered by foreign matter attached to the back surface. Based on the light spectrum of the transmitted light including the first and second scattered lights analyzed by the spectrum analysis means, which of the front surface and the back surface of the transparent substrate has the foreign matter attached to? 11. The light-transmitting substrate inspection device according to claim 10, wherein: Aperture means is provided on an optical path between the back surface of the transmissive substrate and the spectrum analysis means, and the spectrum analysis means is configured to receive the transmitted light via the aperture means. 9. The light-transmitting substrate inspection device according to claim 8, wherein: 9. The light-transmitting substrate inspection apparatus according to claim 8, wherein a wiring pattern is formed on the light-transmitting substrate. 9. The light-transmitting substrate inspection apparatus according to claim 8, further comprising a moving unit that moves the light-transmitting substrate so that an entire area or a predetermined area of the light-transmitting substrate can be inspected.

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