JP2006078426A - Apparatus and method for inspecting defect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect inspecting apparatus and a defect inspection method, capable of stably inspecting defects without requiring a defect inspecting apparatus of complicated structure or reductions in defect inspection accuracy due to the type of objects to be inspected. <P>SOLUTION: The defect inspection apparatus comprises both a light-projecting part for irradiating inspecting light to an object to be inspected and a detection part for detecting transmitted light transmitted through the object to be inspected or reflected light and detecting defects of the object to be inspected. The light projection part comprises both a light irradiation means and a polarizer. The detection part comprises an analyzer and a photodetection means. The polarizer changes the polarization axis of the polarizer according to a polarization axis inherent to the object to be inspected, polarizes the light from the irradiation means, and irradiates the object to be inspected. The analyzer matches its polarization axis to the polarization axis of the polarizer. By detecting transmitted light from the object to be inspected, changes in the amount of transmission through reflected light, or changes in the amount of reflection with the photodetection means, defects of the object to be inspected are detected in the defect inspection apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a defect inspection apparatus for inspecting defects such as a resin film, a substrate, glass, various drums, paper, a steel plate, and a non-ferrous plate.

  Conventionally, in various manufacturing industries that handle resin films, substrates, glass, various drums, paper, steel plates, non-ferrous plates, etc., inspections are performed by defect inspection equipment for materials and products used from the standpoint of improving product quality and stability. Has been done. As a defect inspection apparatus, a method of inspecting a defect of an irradiated object by irradiating the inspection object with inspection light and detecting a change in the amount of transmitted light transmitted through the inspection object or a reflection amount of reflected light is adopted. ing. For example, as an example of a resin film, there is a demand for optical films due to the increase in the number of photo shots and the explosive spread of mobile phones and notebook computers, particularly polarizing plate protective films for liquid crystal display devices, optical compensation films, and the like. . An example of the substrate is a wafer used for manufacturing a semiconductor device. Examples of glass are shadow masks used for television cathode ray tubes, package lead frame masks incorporating IC circuits, masks on which electrodes used in liquid crystal panels are written, and photosensitive materials used to make working masks. The glass plate used as a support body of a glass dry plate is mentioned. As an example of the paper, there is an original roll roll paper before printing for a banknote in which an identification mark, a clearance, and a print mark are formed.

  Any of the examples listed above may cause a fatal effect on the product performance if used overlooking the presence of defects, so it is usually used after a thorough defect inspection to confirm that there are no defects. ing. For example, as a defect inspection device for an optical compensation film, the optical compensation film is irradiated with light passing through a polarizer, the transmitted light is received by a CCD camera through the analyzer, and the obtained information is processed by a processing device. A defect inspection apparatus for detecting a defect is known (see, for example, Patent Document 1).

  However, the defect inspection apparatus described in Patent Document 1 has the following drawbacks. 1) A defect inspection apparatus is complicated because a foreign matter defect caused by foreign matter adhesion and a schlieren defect in which birefringence caused by dirt on the alignment film surface becomes abnormal are separately detected. 2) Due to the relationship between the polarizers on both sides of the object to be inspected, the sensitivity unevenness (shading) of the obtained detection signal may increase.

  As a viewing angle improvement film defect inspection device, a viewing angle improvement film that is an inspection object between a pair of polarizers, and an inspection object that has been confirmed to be free of defects after being rotated 180 degrees in the film plane Place a viewing angle improvement film from a certain range of the viewing angle improvement film, irradiate the inspection light through the polarizer from the viewing angle improvement film side to be inspected, and pass the transmitted light through the analyzer with a CCD camera. A defect inspection apparatus that detects a defect by receiving light and processing the obtained information with a processing apparatus is known (see, for example, Patent Document 2).

However, the defect inspection apparatus described in Patent Document 2 requires a film for correcting sensitivity unevenness (shading) of the obtained detection signal due to the relationship between the polarizers on both sides of the inspection object, and the configuration of the defect inspection apparatus. Has the disadvantage of becoming complicated. Under these circumstances, development of a defect inspection apparatus and a defect inspection method that stably detect defects without inferior defect inspection accuracy is desired depending on the type of inspection object, without using a defect inspection apparatus with a complicated configuration. ing.
JP 2000-28546 A JP 2001-324453 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to detect defects stably without inferior defect inspection accuracy depending on the type of inspection object, without using a defect inspection apparatus having a complicated configuration. A defect inspection apparatus and a defect inspection method are provided.

  The above object of the present invention has been achieved by the following constitution.

(Claim 1)
In a defect inspection apparatus having a light projecting unit that irradiates an inspection object with inspection light, and a detection unit that detects transmitted light or reflected light transmitted through the inspection object and detects a defect of the inspection object,
The light projecting unit has irradiation means and a polarizer,
The detection unit includes an analyzer and light detection means,
The polarizer changes the polarization axis of the polarizer according to the specific polarization axis of the inspection object, polarizes the light from the irradiation means, and irradiates the inspection object,
The analyzer aligns the polarization axis with the polarization axis of the polarizer, and detects the change in the transmission amount or the change in the reflection amount through the transmitted light or reflected light from the inspection object by the light detection means, A defect inspection apparatus for detecting a defect of the inspection object.

(Claim 2)
The defect inspection apparatus according to claim 1, wherein the irradiation unit can irradiate light having a wavelength range of 140 to 40,000 nm.

(Claim 3)
3. The defect inspection apparatus according to claim 1, wherein the difference between the angle of the polarization axis of the polarizer and the angle of the polarization axis of the inspection object is −45 to + 45 °.

(Claim 4)
The defect inspection apparatus according to claim 1, wherein a difference between an angle of a polarization axis of the analyzer and an angle of a polarization axis of the polarizer is −30 to + 30 °. .

(Claim 5)
A mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means which is the light detecting means is provided between or before the light detecting means and the analyzer. The defect inspection apparatus according to any one of claims 1 to 4, wherein the defect inspection apparatus is characterized in that:

(Claim 6)
The defect inspection apparatus according to claim 5, wherein the mask is integrated with an analyzer.

(Claim 7)
A defect inspection apparatus having a light projecting unit that irradiates an inspection object with inspection light and a detection unit that detects transmitted light or reflected light transmitted through the inspection object and detects a defect of the inspection object is used. In the defect inspection method
The light projecting unit has irradiation means and a polarizer,
The detection unit includes an analyzer and light detection means,
The polarizer changes the polarization axis of the polarizer according to the specific polarization axis of the inspection object, polarizes the light from the irradiation means, and irradiates the inspection object,
The analyzer aligns the polarization axis with the polarization axis of the polarizer, and detects the change in the transmission amount or the change in the reflection amount through the transmitted light or reflected light from the inspection object by the light detection means, A defect inspection method characterized by detecting a defect of an irradiated object.

(Claim 8)
The defect inspection method according to claim 7, wherein the irradiation unit can irradiate light having a wavelength range of 140 to 40,000 nm.

(Claim 9)
9. The defect inspection method according to claim 7, wherein a difference between an angle of a polarization axis of the polarizer and an angle of a polarization axis of the inspection object is −45 to + 45 °.

(Claim 10)
The defect inspection method according to claim 7, wherein a difference between an angle of a polarization axis of the analyzer and an angle of a polarization axis of the polarizer is −30 to + 30 °. .

(Claim 11)
A mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means which is the light detecting means is provided between or before the light detecting means and the analyzer. The defect inspection method according to claim 7, wherein the defect inspection method is any one of claims 7 to 10.

(Claim 12)
The defect inspection method according to claim 11, wherein the mask is integrated with an analyzer.

  It is possible to provide a defect inspection apparatus and a defect inspection method that stably detect defects without inferior in defect inspection accuracy depending on the type of inspection object, without making the defect inspection apparatus of a complicated configuration, and make it a final product. It was possible to accurately eliminate defective materials at the previous stage, and it was possible to improve production efficiency.

  Embodiments according to the present invention will be described with reference to FIGS. 1 to 4, but the present invention is not limited thereto.

  FIG. 1 is a schematic diagram showing a basic configuration of a defect detection apparatus. FIG. 1A is a schematic diagram showing a basic configuration of a defect detection apparatus when an object that transmits inspection light is used as an inspection object. FIG. 1B is a schematic diagram illustrating a basic configuration of a defect detection apparatus when an object that reflects inspection light is used as an inspection object.

  In the figure, reference numeral 1 denotes a defect detection apparatus. The defect detection apparatus 1 is an apparatus for detecting an optical defect portion of an object to be inspected, that is, a defect portion having a different birefringence characteristic from a normal portion, or a defect portion such as a foreign matter adhesion defect accompanied by light scattering due to foreign matter adhesion. is there. The defect detection apparatus 1 includes a light projecting unit 2 that irradiates an inspection object 4 with inspection light A, and a detection unit 3.

  The light projecting unit 2 includes a light source 201 and a polarizer 202 that are irradiation means. The irradiation means is preferably capable of irradiating light in a wavelength range of 140 to 40,000 nm. For example, a deuterium lamp is used as a light source for irradiating light in the wavelength range of 140 to 300 nm, a xenon lamp, a tungsten lamp, and light in a wavelength range of 350 to 2000 nm as light sources for irradiating light in the wavelength range of 190 to 2,000 nm. As a light source for irradiating light, a halogen lamp is used, and as a light source for irradiating light in the wavelength range of 1500 to 40,000 nm, an S-glober lamp is used. The light source 201 may be a surface light source that uniformly irradiates a certain area of the film surface of the inspection object 4 or a linear light source that uniformly irradiates one direction of the film surface of the inspection object 4. Good. It is preferable to select appropriately according to the form of the inspection object 4.

  The polarizer 202 is a frame (not shown) of the defect detection apparatus 1 that can be rotated via a drive system so that the polarization axis of the polarizer 202 can be varied in order to align the inspection light with the specific polarization axis of the inspection object 4. ) Is preferable. As a means to arrange | position, the Suruga Seiki Co., Ltd. fine adjustment type | mold polarization holder is mentioned, for example.

  In the measurement, the angle of the polarization axis of the polarizer is preferably −45 to + 45 ° with respect to the angle of the polarization axis of the inspection object. When the angle of the polarization axis of the polarizer is less than −45 °, the difference from the angle of the polarization axis of the object to be inspected increases, the amount of light decreases, the detection signal decreases, and accurate defect detection cannot be performed. There is. When the angle of the polarization axis of the polarizer exceeds + 45 °, the amount of light decreases, the detection signal becomes small, and accurate defect detection may not be possible. The change in the angle of the polarization axis of the polarizer will be described later.

By making the polarization axis of the polarizer 202 variable and adjusting the inspection light within the range of −45 to + 45 ° with respect to the angle of the specific polarization axis of the inspection object 4, the following effects can be obtained.
1) Even if the object to be inspected changes, accurate and stable defect detection is possible.
2) Since the amount of inspection light transmitted (reflection amount) at a normal location of the object to be inspected increases, the detection power increases and at the same time the detection accuracy improves.
3) Since the inspection light transmitted (reflected) through the inspection object is polarized in accordance with the polarization axis of the inspection object, the light quantity distribution of the inspection light applied to the inspection object is stabilized, and the inspection width For this, uniform and stable defect detection becomes possible.

  The detection unit 3 includes an analyzer 301, a light receiving unit 302 serving as a light detection unit, a mask 303, and a signal processing device 304. The analyzer 301 is disposed in front of the light receiving means 302 so that the inspection light A is irradiated onto the inspection object 4 through the polarizer 202 and the inspection light B transmitted (reflected) through the inspection object 4 is transmitted. . Reference numeral 302 a denotes a light receiving portion of the light receiving means 302. Reference numeral 303 a denotes an opening of the mask 303. The mask 303 is disposed to shield inspection light having a different optical path from inspection light transmitted (reflected) through a normal portion having a small scattering angle and passing through the analyzer among inspection light that has become scattered light due to foreign matter. Yes. The position where the mask 303 is disposed may be between the light receiving means 302 and the analyzer 301 (in front of the light receiving portion 302 a) or in front of the analyzer 301. The mask 303 may be a separate body from the analyzer 301 or may be integrated together. It is preferable to select appropriately according to the conditions to be measured. This figure shows a case where the mask 303 and the analyzer 301 are separate bodies.

  The angle of the polarization axis of the analyzer 301 is preferably −30 to + 30 ° with respect to the polarization axis of the polarizer. When the angle of the polarization axis of the analyzer is less than −30 °, the amount of change in the polarization angle of the inspection light due to the defect of the inspection object becomes almost the same as the angle of the polarization axis of the analyzer, thereby detecting the defect. It may not be possible with high accuracy. When the angle of the polarization axis of the analyzer exceeds + 30 °, the amount of change in the polarization angle of the inspection light due to the defect of the inspection object becomes almost the same as the angle of the polarization axis of the analyzer, thereby detecting the defect. May not be accurate. The change in the angle of the polarization axis of the analyzer 301 will be described later. The following effects can be obtained by adjusting the angle of the polarization axis of the analyzer 301 within a range of −30 to + 30 ° with respect to the polarization axis of the polarizer.

  1) Since the amount of inspection light passing through the analyzer increases, the detection power increases and at the same time the detection accuracy improves.

  2) Since the angle of the polarization axis of the inspection light passing through the analyzer corresponds to the angle of the polarization axis of the analyzer, the inspection light passing through the analyzer is uniform and uniform, and the detection accuracy is improved.

  3) When there is a defect in the inspection object, inspection light having a different polarization axis that is transmitted (reflected) through the defect portion does not pass through the analyzer, thereby improving detection accuracy.

  In this figure, the mask 303 shields inspection light having a light path different from that of inspection light having a small scattering angle and transmitted (reflected) through a normal portion that passes through the analyzer, among inspection light that has been scattered by foreign matter. Are disposed between the light receiving means 302 and the analyzer (in front of the light receiving portion 302a). The opening diameter of the opening 303a of the mask 303 is preferably 10 to 100% with respect to the light receiving area. If it is less than 10% with respect to the light receiving area, the amount of received light decreases, and accurate defect detection may not be possible. When the diameter of the opening 303a exceeds 100%, scattered light due to the defect passes and the light receiving unit receives the light, so that highly accurate detection may not be possible.

  By setting the opening diameter of the opening 303a of the mask 303 to 10 to 100% with respect to the light receiving area, the inspection light that has become scattered light due to the foreign matter is transmitted through a normal part having a small scattering angle and passing through the analyzer ( The accuracy of defect detection is improved because the inspection light having a different optical path from the reflected inspection light is shielded.

  The light receiving means 302 is means for receiving the inspection light B transmitted (reflected) through the analyzer 301 and obtaining a luminance signal. For example, a line sensor in which solid-state image sensors on the light receiving surface are arranged in a line in one direction, An area sensor in which solid-state image sensors on a surface are arranged in an area is exemplified. Specifically, a known solid-state image sensor such as a CCD camera having a solid-state image sensor on the light receiving surface or a CMOS image sensor can be used.

  A known optical system lens (not shown) that collects the inspection light B transmitted through the analyzer 301 to form an image on the light receiving surface of the light receiving means 302 is used between the analyzer 301 and the light receiving means 302. It doesn't matter. For example, when a CCD camera is used as the light receiving means 302, the value of the luminance signal obtained by the amount of the inspection light B when the light is received by the light receiving surface of the CCD camera changes depending on the viewing angle depending on the light receiving position of the light receiving surface of the CCD camera. It is preferable to use an optical lens that prevents image formation and forms an image on the light receiving surface of the CCD camera. In addition, it is particularly preferable to use an optical system lens when detecting the defect portion with high accuracy by reducing the viewing angle dependency or when the luminance signal value is small and the SN ratio of the defect portion is small. Reference numeral 305 denotes a drive circuit for driving the light receiving means 302 to detect the inspection light B.

  A signal processing device 304 is connected to the light receiving means 302. The signal processing device 304 includes a band-pass filter 304a, a binarization circuit 304b having a comparator set value, and a defect detection circuit 304c. The band pass filter 304a transmits only the signal in the frequency band necessary for the inspection among the output signals from the light receiving means 302. The binarization circuit 304b monitors the level of the output signal that has passed through the bandpass filter 304a, and outputs a defect signal when the level exceeds a predetermined range. The defect detection circuit 304c detects the presence / absence of a defect based on the signal output from each binarization circuit 304b, and counts the length in the direction in which the inspection object is conveyed and the number of defects by the counter 304d. The defect level is calculated using the memory 304e, and a defect signal and defect position information can be output.

  As shown in FIG. 1A, when the inspection object is an object that transmits inspection light, the irradiation angle of the inspection light from the irradiation means to the inspection object is preferably 0 to 60 °. When the irradiation angle exceeds 60 °, the amount of reflected light increases and the amount of incident light decreases, so that the inspection signal becomes small and accurate defect detection may not be possible.

  As shown in FIG. 1B, when the inspection object is an object that reflects inspection light, the irradiation angle of the inspection light from the irradiation unit to the inspection object is preferably 0 to 75 °. When the irradiation angle exceeds 75 °, a slight change in the inspected object has a large influence on the amount of reflected light, the accuracy of defect detection is lowered, and accurate defect detection may not be performed.

  For example, when the inspection object is small, the defect detection apparatus shown in this figure can be used for inspection by moving the defect detection apparatus when the inspection object is small. In the case of a strip shape, it is possible to inspect continuously while moving the object to be inspected. Next, a method for detecting a defect present in an inspection object using the defect detection apparatus shown in FIG. 1 will be described.

  FIG. 2 is a schematic diagram of a method for detecting defects existing in the inspection object using the defect detection apparatus shown in FIG.

  The inspection light from the light source 201 is polarized by the polarizer 202 so that the difference from the angle of the polarization axis of the inspection object 4 is −45 to + 45 °. Polarized inspection light A is applied to the inspection object 4. At this time, when there are a portion 401 where foreign matter is attached to the inspection object 4, a portion 402 of abnormal orientation due to crystal defects, and a normal portion 403, the behavior of the inspection light is as follows.

  At the spot 401 where the foreign matter has adhered, the inspection light A is scattered by the foreign matter to become scattered light D, part of it is scattered outside the system, and the inspection light D ′ having a small scattering angle passes through the analyzer 301 and reaches the mask 303. To do. The inspection light D ′ reaching the mask 303 changes in accordance with the size of the scattering angle caused by the foreign matter. The inspection light D ′ that has reached the mask 303 has a different optical path from the inspection light B that has passed through the normal portion, and is thus shielded by the mask 303 disposed in front of the light receiving portion of the light receiving means 302, and from the opening 303 a to the light receiving portion 302 a. It is designed not to enter. Thereby, the detection accuracy with respect to a defect which scatters inspection light improves. The inspection light A becomes the light C whose polarization angle changes at the location 402 where the orientation is abnormal due to the crystal defect, and reaches the detection unit 3, but can pass through the analyzer 301 because it is different from the polarization angle of the analyzer 301. It is no longer possible. Therefore, no inspection light reaches the light receiving means 302. In the normal location 403, since the inspection light A has no obstacle, it passes through the analyzer 301 in which the polarization angle of the analyzer 301 is set to −30 to + 30 ° with respect to the polarization angle of the polarizer 202. To reach the light receiving means 302. In this way, the signal obtained by the light receiving means 302 is sent to the signal processing device 304 and processed for defect determination. Other reference numerals are the same as those in FIG.

  That is, in terms of a model, for example, when 100 inspection light A is irradiated onto an inspection object, 30% is present at a spot 401 where foreign matter has adhered, 50% at a normal spot 403, and an abnormal position due to crystal defects. Assume that 20% of the inspection light is irradiated to 402. In this case, the scattered light is reduced at the spot where the foreign matter is attached, and 20% of the irradiated inspection light reaches the light receiving means 302, and the inspection reaching the light receiving means 302 at the location 402 where the orientation is abnormal due to crystal defects. The light becomes 0%, and 100% of the irradiated inspection light reaches the light receiving means 302 at a normal location. As a result, with respect to 50% of the inspection light irradiated to the normal part of the object to be inspected, the inspection light at the part where the orientation is abnormal is 0, the difference from the normal part is 0/50, and foreign matter is attached. Since the difference from the normal location is 6/50 at the location that has been done, it is determined that there is a defect at this location.

  FIG. 3 is a schematic diagram of a defect signal pattern obtained by performing defect detection using the defect detection apparatus shown in FIG. FIG. 3A is a schematic diagram of a defect signal obtained by performing defect detection on an inspection object having two defects of orientation anomalies using the defect detection apparatus shown in FIG. . FIG. 3B is a schematic diagram of a defect signal obtained by performing defect detection on an inspection object having three foreign substance attachment defects using the defect detection apparatus shown in FIG. . FIG. 3 (c) is obtained by performing defect detection on an inspection object having two orientation abnormality defects and two foreign matter adhesion defects using the defect detection apparatus shown in FIG. 1 (a). It is a schematic diagram of a defect signal.

  In the figure, A1 and A2 indicate defect locations with abnormal alignment, B1 to B3 indicate defect locations with foreign matter adhesion, and 1 to 6 indicate the number of scans. That is, this figure shows that the inspection object 4 has been scanned six times from the top to the bottom in the full width direction (the direction of the arrow in the figure). The pattern is shown.

  In the case of an inspected object having two abnormal alignment defects A1 and A2 shown in FIG. 3A, the inspection light is polarized by the abnormal alignment defects A1 and A2, and therefore does not pass through the analyzer. Is not recorded and is recorded as a defect signal. In this figure, W corresponds to the defect A1, and V corresponds to the defect A2. From this result, it is detected that there are two defects in the inspection object.

  In the case of the inspected object having the foreign matter adhesion defects B1 to B3 shown in FIG. 3B, the inspection light becomes scattered light at the foreign matter adhesion defects B1 to B3, and a part of the inspection light is out of the optical path. Small inspection light passes through the analyzer, but is shielded by the mask in front of the light receiving means, and is recorded as a defect signal. In this figure, X corresponds to the defect B1, Y corresponds to the defect B2, and Z corresponds to the defect B3. From this result, it is detected that there are three defects in the inspection object.

  In the case of the inspected object having two orientation abnormalities A1 and A2 and three foreign matter defects B1 to B3 shown in FIG. 3C, in this case, FIG. The defect signal shown in (b) of 3 is a combined defect signal, and it is detected that there are five defect portions.

As shown in this figure, in the defect detection apparatus of the present invention, it is difficult to analyze a defect whose polarization axis direction changes or a light scattering defect from the obtained defect signal, but it detects the presence or absence of a defect in the inspection object. Has a simple structure and excellent functions.
FIG. 4 is a schematic flow chart until the defect detection is performed using the defect detection apparatus shown in FIGS.

  The steps until defect detection is performed using the defect detection apparatus shown in FIGS. 1 and 2 will be described step by step. In S1, the amount of polarization angle with respect to the conveyance direction of the object to be inspected is obtained using a VPMM-100 manufactured by Suruga Seiki Co., Ltd.

  In S2, the polarization axes of the polarizer of the light projecting unit and the analyzer of the detecting unit are obtained in advance using a VPMM-100 manufactured by Suruga Seiki Co., Ltd., and the polarizer and the analyzer are marked along the direction of the polarization axis.

  In S3, the polarization axis of the polarizer determined in S2 is finely adjusted by Suruga Seiki Co., Ltd. by the required polarization angle amount corresponding to the polarization angle amount with respect to the conveyance direction of the inspection object determined in S1. Align using a polarizing holder.

  In S4, the Suruga Seiki Co., Ltd. product makes the polarization axis of the analyzer of the detection unit by the amount of polarization angle required in the direction of the polarization axis finely adjusted in accordance with the polarization angle of the polarizer with respect to the conveyance direction of the inspection object. Use a fine-tuning polarization holder.

  In S5, a mask having an opening with a required opening diameter of 10 to 100% is placed before (after) the analyzer of the detection unit.

  In S6, the inspection object is irradiated with inspection light and inspection is started.

  By passing through the steps S1 to S6, it becomes possible to easily detect the defect of the inspection object. The following effects can be obtained by the defect inspection apparatus and the defect inspection method shown in FIGS. 1) A defect inspection apparatus having a simple configuration can be provided, and stable defect inspection is possible. 2) Even if the inspection object changes, stable defect detection can be performed with high accuracy.

  The test object according to the present invention is not particularly limited, and examples thereof include a resin film, a substrate, glass, various drums, paper, a steel plate, and a non-ferrous plate. Specifically, as a resin film, acrylic film, pet film, vapor deposition film, polarizing film, film, light diffusion film, AR film, multilayer film, coating film, cellophane film, A-PET film, polyamide film, retardation Film, magnetic tape, vinyl chloride film, rubber sheet, etc. are raised. The types of defects include, for example, unevenness, holes, black spots, foreign matter, pinholes, scratches, scratches, spots, thin stains, smudges, dirt, thin stains, fish eyes, foreign matter contamination, blisters, gels, spots, unevenness, color Examples include unevenness, wrinkles, streaks, and die lines.

  Examples of the substrate and glass include raw glass, coated glass, a glass substrate, a laminated substrate, and a BGA seal substrate. Examples of the types of defects include holes, pinholes, black spots, foreign matters, dirt, scratches, sludge, bubbles, and the like.

  Examples of the various drums include an aluminum base tube, a rubber roll, a photosensitive drum, and automobile parts. Examples of the types of defects include scratches, burn-in, foreign matter, stains, stuffiness, indentation, white spots, streaks, irregularities, and dents.

  Examples of the paper include a photosensitive material support, resin-coated paper, printing paper, banknote paper, and the like. Examples of the type of defect include a stain, a foreign object, a wrinkle, a stain, an unevenness, and a dropout.

Examples of steel plates and non-ferrous plates include steel plates (CPL, CGL, EGL, CAL, etc.), copper plates, brass plates, stainless steel plates, aluminum plates, copper foils, aluminum foils, electrode plates, electronic materials, and the like.
The types of defects include, for example, unevenness, shavings, holes, black spots, pinholes, scratches, wrinkles, scabs, spots, dirt, spots, unevenness, white spot marks, peeling, spots, spots, plating exposure, and foreign matter. , Pressing marks, roll marks, polishing marks, uneven gloss, scratches, poor plating, welding marks, stained chromate, gloss spots, and the like.

  Hereinafter, although the effect of the present invention is concretely explained by an example, the present invention is not limited to these.

Example 1
(Preparation of inspection object)
A cellulose ester film was produced as an object to be inspected by the following method.
(Preparation of dope composition)
Cellulose triacetate 100 parts by weight Triphenyl phosphate 13 parts by weight 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl)
Benzotriazole 3 parts by weight Aerosil R200V (manufactured by Nippon Aerosil Co., Ltd.) 0.1 part by weight Methylene chloride 475 parts by weight Ethanol 50 parts by weight The above was put into a sealed container and completely dissolved while stirring at 41 ° C.

(Preparation of film)
The dope composition was filtered, and uniformly cast with a width of 1000 mm on a support at a dope temperature of 33 ° C. The speed of the support is 20 m / min while the temperature is controlled, the solvent is evaporated, and after peeling off from the support with a residual solvent amount of 120%, the drying in the roll transport drying process is performed until the residual solvent amount reaches 80% by mass. It was performed at 50 ° C. at 30 ° C. and less than 80% by mass. Next, in the tenter conveying / drying step, the residual solvent amount was 80 ° C. up to 20% by mass, less than 20% by mass at 100 ° C., and roll drying after the tenter was performed at 130 ° C. to prepare a cellulose ester film. The thickness of the film at the end of drying was 60 μm, and the residual solvent amount was less than 0.1% by mass.

  The measurement of the residual solvent amount is a value obtained from the following equation, where A is the mass of the film when the film is dried at 115 ° C. for 1 hour, and B is the mass of the film before drying.

((BA) / A) × 100 = residual solvent amount (% by mass)
(Defect inspection)
The defect inspection of the prepared cellulose ester film is performed using the defect inspection apparatus shown in FIG. 1A, and according to the schematic flow chart shown in FIG. Defect detection is performed under inspection conditions 101 to 154 in which the amount of polarization angle of the analyzer and the aperture ratio of the mask are changed. Table 1 shows the results obtained by calculating the S / N value of the detection power at the time and evaluating it according to the following evaluation rank. In addition, the polarization angle amount of a polarizer shows the difference of the angle with respect to the polarization angle amount with respect to the conveyance direction of the cellulose-ester film of a to-be-inspected object. The polarization angle amount of the analyzer indicates a difference in angle with respect to the polarization angle amount required in the polarization axis direction finely adjusted corresponding to the polarization angle amount of the polarizer with respect to the conveyance direction of the inspection object. The light source used was tungsten light and was a surface light source. Moreover, the irradiation angle with respect to the to-be-inspected object was 56.3 degrees. A CCD camera is used as the light receiving means, and the opening diameter of the mask indicates a ratio to the light receiving area of the CCD camera.

Defect signal evaluation rank ○: S / N ≧ 3, stable defect can be detected reliably. Δ: 2 ≦ S / N <3, both when it can be detected and when it cannot be detected. ×: S / N <2. And difficult to detect

  Using the defect inspection apparatus of the present invention, a mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means is placed in front of the light receiving means, and the angle of the polarization axis of the polarizer, The detection condition is set such that the difference from the angle of the polarization axis of the inspection object is −45 to + 45 °, and the angle of the polarization axis of the analyzer and the angle of the polarization axis of the polarizer are −30 to + 30 °. Thus, it was confirmed that the defect can be detected with high accuracy even when a defect whose polarization direction changes and a light scattering defect coexist, and the effectiveness of the present invention was confirmed.

Example 2
(Preparation of inspection object)
A silicon wafer with a diameter of 48 mm, coated with polymethamethyl acrylate (PMMA) at a thickness of 1 μm, was prepared.

(Defect inspection)
Defect inspection of the prepared silicon wafer is carried out by visual observation and using the defect inspection apparatus shown in FIG. 1B, and according to the schematic flow chart shown in FIG. Inspection conditions 201 to 254 with different angular amounts, analyzer polarization angle amounts and mask aperture ratios are detected, the defect signal state is obtained in the same manner as in Example 1, and the S / N value is obtained in the same manner as in Example 1. Table 2 shows the results of evaluation based on the evaluation rank.

  The polarization angle amount of the polarizer indicates an angle difference with respect to the polarization angle amount with respect to the conveyance direction of the silicon wafer of the inspection object. The polarization angle amount of the analyzer indicates a difference in angle with respect to the polarization angle amount necessary for the polarization direction finely adjusted corresponding to the polarization angle amount of the polarizer with respect to the conveyance direction of the inspection object. The light source used was tungsten light and was a surface light source. The irradiation angle with respect to the object to be inspected was 60 °. A CCD camera is used as the light receiving means, and the opening diameter of the mask indicates a ratio to the light receiving area of the CCD camera.

  Using the defect inspection apparatus of the present invention, a mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means is placed in front of the light receiving means, and the angle of the polarization axis of the polarizer, The detection condition is set such that the difference from the angle of the polarization axis of the inspection object is −45 to + 45 °, and the angle of the polarization axis of the analyzer and the angle of the polarization axis of the polarizer are −30 to + 30 °. Thus, it was confirmed that the defect can be detected with high accuracy even when a defect whose polarization direction changes and a light scattering defect coexist, and the effectiveness of the present invention was confirmed.

It is a schematic diagram which shows the basic composition of a defect detection apparatus. It is a schematic diagram of the detection method of the defect which exists in to-be-inspected object using the defect detection apparatus shown by (a) of FIG. It is a schematic diagram of a defect signal obtained by performing defect detection using the defect detection apparatus shown in FIG. FIG. 3 is a schematic flowchart up to defect detection using the defect detection apparatus shown in FIGS. 1 and 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Defect detection apparatus 2 Light projection part 201 Light source 202 Polarizer 3 Detection part 301 Analyzer 302 Light receiving means 302a Light reception part 303 Mask 303a Opening part 304 Signal processing apparatus 4 Inspected object

Claims (12)

In a defect inspection apparatus having a light projecting unit that irradiates an inspection object with inspection light, and a detection unit that detects transmitted light or reflected light transmitted through the inspection object and detects a defect of the inspection object,
The light projecting unit has irradiation means and a polarizer,
The detection unit includes an analyzer and light detection means,
The polarizer changes the polarization axis of the polarizer according to the specific polarization axis of the inspection object, polarizes the light from the irradiation means, and irradiates the inspection object,
The analyzer aligns the polarization axis with the polarization axis of the polarizer, and detects the change in the transmission amount or the change in the reflection amount through the transmitted light or reflected light from the inspection object by the light detection means, A defect inspection apparatus for detecting a defect of the inspection object. The defect inspection apparatus according to claim 1, wherein the irradiation unit can irradiate light having a wavelength range of 140 to 40,000 nm. 3. The defect inspection apparatus according to claim 1, wherein the difference between the angle of the polarization axis of the polarizer and the angle of the polarization axis of the inspection object is −45 to + 45 °. The defect inspection apparatus according to claim 1, wherein a difference between an angle of a polarization axis of the analyzer and an angle of a polarization axis of the polarizer is −30 to + 30 °. . A mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means which is the light detecting means is provided between or before the light detecting means and the analyzer. The defect inspection apparatus according to any one of claims 1 to 4, wherein the defect inspection apparatus is characterized in that: The defect inspection apparatus according to claim 5, wherein the mask is integrated with an analyzer. A defect inspection apparatus having a light projecting unit that irradiates an inspection object with inspection light and a detection unit that detects transmitted light or reflected light transmitted through the inspection object and detects a defect of the inspection object is used. In the defect inspection method
The light projecting unit has irradiation means and a polarizer,
The detection unit includes an analyzer and light detection means,
The polarizer changes the polarization axis of the polarizer according to the specific polarization axis of the inspection object, polarizes the light from the irradiation means, and irradiates the inspection object,
The analyzer aligns the polarization axis with the polarization axis of the polarizer, and detects the change in the transmission amount or the change in the reflection amount through the transmitted light or reflected light from the inspection object by the light detection means, A defect inspection method characterized by detecting a defect of an irradiated object. The defect inspection method according to claim 7, wherein the irradiation unit can irradiate light having a wavelength range of 140 to 40,000 nm. 9. The defect inspection method according to claim 7, wherein a difference between an angle of a polarization axis of the polarizer and an angle of a polarization axis of the inspection object is −45 to + 45 °. The defect inspection method according to claim 7, wherein a difference between an angle of a polarization axis of the analyzer and an angle of a polarization axis of the polarizer is −30 to + 30 °. . A mask having an opening with an opening diameter of 10 to 100% with respect to the light receiving area of the light receiving means which is the light detecting means is provided between or before the light detecting means and the analyzer. The defect inspection method according to claim 7, wherein the defect inspection method is any one of claims 7 to 10. The defect inspection method according to claim 11, wherein the mask is integrated with an analyzer.

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