JP3924809B2 - Thin film multilayer substrate manufacturing method and pattern inspection apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a thin film multilayer wiring board and a pattern inspection apparatus.
[0002]
[Prior art]
A technique for manufacturing a thin film multilayer wiring board, in particular, a pattern inspection technique for thin film wiring is described in Japanese Patent Laid-Open No. 4-102395. According to this, every time a wiring pattern is formed in the manufacturing process, the most recently formed wiring pattern is detected, the presence or absence of defects in this wiring pattern is inspected, the defective portion is corrected, and the wiring of the next layer is then detected. Form a pattern. As a wiring pattern inspection technology, for example, the inspection object is illuminated from one direction, and regular reflection light and scattered light of a limited wavelength are detected to optically reveal the wiring pattern and inspect wiring pattern defects. Technology to do is shown. In addition, the inspection target is illuminated from multiple directions, the reflected light of a limited wavelength is detected, the wiring pattern is inspected, or the inspection target is illuminated with linearly polarized light and the polarization component orthogonal to the polarization direction of the illumination light A technique for inspecting and detecting a wiring pattern and inspecting a wiring pattern, and a technique for inspecting a wiring pattern by detecting fluorescence generated by an inspection object are shown.
[0003]
[Problems to be solved by the invention]
In the manufacturing technique of a thin film multilayer wiring board, the wiring pattern formed most recently is inspected every time a wiring pattern is formed, a wiring pattern defect detected by this inspection is corrected, and the thin film multilayer wiring board is manufactured. However, the inspection and correction of the insulating film that insulates the interlayer of the wiring pattern is not performed. For this reason, if a defect occurs in the insulating film that insulates the interlayer of the wiring pattern during the manufacturing process, a short circuit failure may occur, and the completed thin film multilayer wiring board may become defective.
[0004]
The thin film wiring pattern inspection technique can be effectively inspected only when a thin film multilayer wiring board having a specific structure is targeted, and cannot be inspected depending on the inspection target process. For example, a technique for detecting and inspecting fluorescence is effective only when a fluorescent material is used. If inspection is performed every time a wiring pattern is formed in a manufacturing process of a thin film multilayer wiring board, the inspection process reaches a plurality of processes. For this reason, it is difficult to inspect all the inspection processes with one inspection technique among the thin film wiring pattern inspection techniques, and it is necessary to use a plurality of inspection techniques for each of the special inspection processes. That is, a plurality of inspection apparatuses having different inspection methods are required. Furthermore, if the manufacturing process of the thin film multilayer wiring board is changed, the inspection apparatus used so far cannot be inspected and a new inspection apparatus may be required.
[0005]
The objective of this invention is providing the manufacturing method which improves the manufacture yield of a thin film multilayer wiring board.
[0006]
Another object of the present invention is to provide an automatic visual inspection apparatus for a thin film multilayer wiring board.
[0007]
[Means for Solving the Problems]
A thin film multilayer wiring board is manufactured by alternately laminating insulating layers and wiring layers on a ceramic substrate. The insulating layer and the wiring layer are formed by a lithography technique in which, for example, a resist is applied, and after exposure / development, patterning is performed by etching. The present invention improves the yield by a manufacturing method in which the most newly formed layer is inspected every time each layer is formed, and if there is a defect, the next layer is formed on the corrected layer. It is. When a new layer is formed regardless of whether it is an insulating layer or a wiring layer, the resist pattern after the exposure / development is first inspected, and the resist defect detected by this inspection is corrected and then etched. Next, a pattern inspection of the etched insulating layer or wiring layer is performed, and defects detected by this inspection are corrected. In this manner, a non-defective thin film multilayer wiring board is manufactured by forming the next layer in a state where defects are eliminated.
[0008]
In order to realize this manufacturing method, an automatic visual inspection apparatus for inspecting a resist pattern, a wiring pattern, and an insulating layer pattern is necessary. In order to inspect in multiple inspection processes with different materials, surface conditions, and structures, the thin-film multilayer wiring board is illuminated from multiple directions, and the amount of illumination light from each direction is adjusted to the optimum value for each inspection process. The wavelength range of illumination is adjusted to the optimum value for each inspection process, light in a certain wavelength range is detected from the reflected light from the thin-film multilayer wiring board, and the detected wavelength range is optimized for each inspection process. The pattern is detected by means of adjustment. Using this detection optical system, the most recently formed layer is optically revealed and detected. At this time, in order to keep the detection optical system at a constant temperature and prevent defocusing of the lens, the illumination light source is housed in a housing separate from the detection optical system. The image signal thus detected is A / D converted into a digital image signal, and then image processing is performed to detect a pattern defect. In image processing, defect candidates are detected at high speed by hardware processing based on logic implemented in an electric circuit, and then the defect candidates are subjected to image processing optimal for each inspection process by software processing using an electronic computer. Extract defects. As described above, by realizing the optimum pattern detection method and defect extraction processing method for each inspection process, it is possible to inspect the thin film multilayer wiring board with one automatic inspection apparatus.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method for manufacturing a thin film multilayer wiring board according to the present invention will be described with reference to FIG. The multilayer ceramic substrate 100 has a copper pad 101 on its surface. In step (a), an insulating film 102a of polyimide resin is applied on the multilayer ceramic substrate 100. In step 2, a photoresist 103 is applied, exposed and developed. Next, the patterned photoresist 103 is inspected, and the presence / absence of a defect and the location of the defect are output. In step (c), the defective portion is corrected based on the result. For example, the surplus defect of the photoresist is irradiated with laser light to skip the surplus portion. Photoresist chips and pin poles are locally applied in minute amounts. If the number of defects is large, the photoresist may be peeled off and the process may return to step (b) to re-pattern the photoresist. In the step (d), the insulating film 102a is etched using the photoresist as a mask to form a through hole 102b for connection to the pad 101. In step (e), after the photoresist is removed, the insulating film is baked. Next, the insulating film 102c is inspected, and the presence / absence of a defect and the location of the defect are output. In step (f), the defective portion is corrected based on the result. For example, when the through hole is not opened in the insulating film, the through hole is formed by irradiating laser light. A small amount of resin is locally applied to the chipping or pin pole of the insulating film. Further, when the number of defects is large, it may be considered that the insulating film is peeled off and the process returns to the step (a) to form the insulating film again. As described above, one insulating layer is completed in steps (a) to (f).
[0010]
Next, in step (g), a metal film 104a to be a wiring is formed. For example, chromium, copper, and chromium are continuously formed by sputtering, and a three-layer metal film is used as a wiring. In step (h), a photoresist 105 is applied, exposed and developed. Next, the patterned photoresist 105 is inspected, and the presence / absence of a defect and the location of the defect are output. In step (i), the defective portion is corrected based on the result. For example, the surplus defect of the photoresist is irradiated with laser light to skip the surplus portion. Photoresist chips and pin poles are locally applied in minute amounts. If the number of defects is large, the photoresist may be peeled off, and the process may return to step (h) to repattern the photoresist. In step (j), the metal film 104a is etched using the photoresist as a mask to form a wiring pattern 104b. In step (k), the photoresist is removed. In step (l), the metal film 104b is inspected, and the presence / absence of a defect and the location of the defect are output. In step (l), the defective portion is corrected based on the result. For example, the surplus defect of the metal film is irradiated with laser light to skip the surplus portion. As described above, one wiring layer is completed in steps (g) to (l).
[0011]
Thereafter, steps (a) to (f) and steps (g) to (l) are repeated to form a multilayer insulating layer and a wiring layer, thereby completing a thin film multilayer wiring substrate.
[0012]
According to this embodiment, since the insulating layer and the wiring layer that are free from defects can be stacked, the manufacturing yield can be increased.
[0013]
An embodiment of a thin film multilayer wiring board manufacturing system will be described with reference to FIG. The manufacturing system includes an appearance inspection apparatus 201, a laser cut correction apparatus 202, a local coating correction apparatus 203, an exposure apparatus 210, a developing apparatus 211, a film forming apparatus 212, an etching apparatus 213, a coating apparatus 214, a baking furnace 215, a peeling apparatus 216, and the like. Consists of Using these apparatuses, a thin film multilayer wiring board is manufactured according to the manufacturing process shown in FIG. The appearance inspection device 201, the laser cut correction device 202, and the local application correction device 203 are connected to the network 205, and the inspection result data of the appearance inspection device 201 is transferred to the laser cut correction device 202 and the local application correction device 203. . The defective part is corrected according to the transferred data. The inspection result data is managed by the host computer 204.
[0014]
According to the present embodiment, the inspection device and the correction device are connected online, and the inspection result of the inspection device can be transferred to the correction device, so that the efficiency of the correction work is improved.
[0015]
FIG. 3 shows the overall configuration of an appearance inspection apparatus for a thin film multilayer wiring board. A thin film multilayer wiring board 301 to be inspected is chucked by a work holder 302 and mounted on an XYZθ stage 303. The XYZθ stage 303 is driven by the controller 304. The movement is instructed by the computer 305, and the instruction is transmitted to the controller 304 via the bus 306.
[0016]
The illumination is a combined illumination of oblique illumination and epi-illumination from the entire circumference by the multiple ring light guide 310. The multiple ring light guide guides light from the light source group 311 to the thin film multilayer substrate 301 and illuminates the thin film multilayer substrate from an oblique direction from the entire periphery. The epi-illumination is realized by the light source 312, the condenser lens 313, the half mirror 314, and the objective lens 315. The light from the light source is guided to the half mirror through the condenser lens, and the thin film multilayer substrate is illuminated through the objective lens.
[0017]
The reflected light from the thin film multilayer substrate 301 is imaged on the linear sensor 317 by the objective lens 315 and the imaging lens 316, and an image is detected. A filter 318 is inserted in the middle of the optical path to limit the detection wavelength. By synchronizing the scanning of the XYZθ stage 303 and the driving of the linear sensor, a two-dimensional image signal is detected.
[0018]
The image signal is converted into a digital signal by the A / D converter 320, subjected to dark level correction, stage speed fluctuation correction, shading correction, and the like by the preprocessing circuit 321, and becomes a binary image by the binarization circuit 322. The binary image is processed by the defect detection circuit 323 to detect a defect. The presence / absence of the defect and the position of the defect are output to the computer 305 via the bus 306.
[0019]
Hereinafter, details of each element of the appearance inspection apparatus will be described.
[0020]
First, the configuration of the detection optical system is shown in FIG. The six-ring light guide 401 is an optical fiber light guide that illuminates the thin film multilayer wiring substrate 301 from six angles in the entire circumference and height direction. The illumination angles α of the light emitting portions 402a, 402b, 402c, 402d, 402e, and 402f arranged in a ring shape are 16 °, 28 °, 40 °, 51.5 °, 63 °, and 74.5 °, respectively. is there. The light emitting section 402a is connected to the lamp house 403a by an optical fiber, 402b is connected to 403b, 402c and 402d are connected to 403c, and 402e and 402f are connected to 403d.
[0021]
The lamp houses 403a to 403d condense light at the fiber end, an electric mechanical aperture 404 for adjusting the amount of light, a shutter 405 that opens and closes an optical path, a filter 406 that limits an illumination wavelength, a lamp 407 that generates light, and a fiber end. An elliptical mirror 408 is incorporated. As the lamp 407, a mercury lamp or a water source xenon lamp is used. The electric mechanical aperture 404 and the shutter 405 are controlled according to the command of the computer 305 shown in FIG. Since the light quantities of the four lamp houses can be controlled independently, the illumination light quantity for each angle of the six-ring light guide can be adjusted. That is, 16 ° is called the upper stage 1, 28 ° is called the upper stage 2, 40 ° and 51.5 ° are together called the middle stage, and 61.5 ° and 74.5 ° are together called the lower stage. The light quantity balance between the upper stage 1, the upper stage 2, the middle stage, and the lower stage can be freely set. In this embodiment, four lamp houses are used. However, when six lamp houses are used, the illumination balance of all six angles can be adjusted.
[0022]
The fiber length of the six-ring light guide is increased to several meters, and the lamp house 403 is mounted in the light source casing 409. The lamp house generates a considerable amount of heat, so when the number of lamp houses increases, the total amount of heat becomes enormous. A lens used for the detection optical system, particularly an objective lens, is sensitive to a temperature change, and the focal length changes. For this reason, when the lamp house is mounted in the same housing as the detection optical system, the temperature of the detection optical system changes due to the waste heat of the lamp house, the focal position moves, and the focus is out of focus. In order to prevent this, the lamp house is mounted in a light source casing different from the casing in which the detection optical system is housed.
[0023]
Epi-illumination is Koehler illumination. The light generated by the lamp 410 is once converted into parallel light by the condenser lens 411, and then the light is bent by 90 ° by the half mirror 415 via the relay lenses 413 and 414 and illuminated through the objective lens 416. An electric turret 412 incorporating various filters 421 is disposed in the parallel light between the condenser lens and the relay lens. The electric turret is controlled in accordance with the command of the computer 305 shown in FIG. 3, and the built-in filter 421 can be freely selected. If a light shielding plate is built in as a filter, a shutter function can also be realized. If an ND filter is built in, the amount of illumination light can be controlled. At this time, it is preferable to increase the number of electric turrets so that a plurality of filters are simultaneously inserted into the optical path.
[0024]
The objective lens 416 is preferably an infinity correction method, and is used as a pair with the imaging lens 417. The magnification is determined by the minimum defect size to be detected. For example, if the minimum line width of the thin film wiring to be inspected is about 30 μm, a 5 × objective lens is used. When a plurality of imaging lenses having different magnifications are prepared and attached to the electric turret, the detection pixel size can be freely selected. A 1.3 × imaging lens 417a, a 0.87 × imaging lens 417b, and a 0.65 × imaging lens 417c are attached to the electric turret 418. When the line sensor 419 having a pixel pitch of 13 μ is used, the detected pixel dimensions are 2 μm, 3 μm, and 4 μm, respectively. A TDI (Time Delay & Integration) line sensor is suitable for the line sensor, and a very bright image can be obtained. The electric turret 418 is controlled in accordance with the instruction of the computer 305 shown in FIG. 3, and the detection pixel size can be freely selected. An electric turret 420 incorporating various filters 422 is disposed in the parallel light between the half mirror 415 and the imaging lens. The electric turret is controlled in accordance with the command of the computer 305 shown in FIG. 3, and the built-in filter 422 can be freely selected. For example, if a wavelength limiting filter is built in, the detection wavelength can be selected.
[0025]
According to the present embodiment, the light amount can be adjusted for each illumination angle of the multiple ring light guide, and the light amount of the epi-illumination can also be adjusted, so that an optimal light amount balance can be realized for each inspection process. Furthermore, since the detection wavelength can be switched, an image can be detected at a wavelength that provides the best contrast for each inspection process. In addition, since the detection pixel size can be changed, the inspection can be efficiently performed even if the pattern size is different for each inspection process, and the inspection time is shortened.
[0026]
It will be described with reference to FIG. 5 that the six-ring light guide is effective for detecting a pattern having a step. Consider a pattern 501 having a step with an inclination angle θ. If the illumination angle of the illumination light 502 of the ring light guide is α and the opening angle of the objective lens 503 is φ, the reflected light 504 that satisfies the relationship of 90 ° −φ <2θ + α <90 ° + φ can be captured by the objective lens. . For example, an objective lens having a numerical aperture NA = 0.14 (aperture angle φ = 8 °) is used, and an illumination angle α = 16 °, 28 °, 40 °, 51.5 °, 63 °, If the angle is 74.5 °, a step having an inclination angle θ from 0 ° to 41 ° can be detected together with the epi-illumination.
[0027]
The reason why the light quantity balance for each illumination angle of the multiple ring light guide needs to be optimized for each inspection process in the inspection of the thin film multilayer wiring board will be described. FIG. 6 is a cross section in an inspection process of a thin film multilayer wiring board. The multilayer ceramic substrate 601 has a copper pad 602 on its surface. The insulating layer 603 is a polyimide resin, and a through hole 610 is formed on the pad 602. The wiring layer 604 is, for example, a three-layer metal film of chromium, copper, and chromium, and is also formed on the pad 602 by the through hole 610. A through hole 612 is formed in the insulating layer 605 formed on the wiring layer 604, and a step 611 is generated due to the edge of the wiring layer 604. The uppermost layer is a wiring layer 606. In the appearance inspection of the wiring layer 606, it is necessary to detect the wiring layer 606 and the insulating layer 605 separately. When the detection wavelength is limited to purple, the metal wiring layer can be bright and the polyimide resin insulating layer 605 can be detected dark. However, if only the epi-illumination is provided, the inclined portions due to the through holes 610 and 612 are detected darkly, and the entire wiring layer 606 cannot be detected brightly. In order to detect this inclined portion brightly, oblique illumination by a multiple ring light guide is required. In the illumination by the multiple ring light guide, not only the step due to the through holes 610 and 612 is brightened, but also the step 611 of the insulating layer 605 can be detected brightly due to the surface reflection of the polyimide insulating film. Since the through-hole 610, the through-hole 612 and the step 611 have different inclination angles, the light intensity balance of each illumination angle of the multiple ring light guide is set so that the step by the through-holes 610 and 612 is brightened and the step 611 is detected dark. Just do it. Further, since the inclination angle of the step desired to be brightened and the inclination angle of the step desired to be dark differ for each inspection process, it is necessary to optimize the light amount balance for each inspection process. This can be realized by the detection optical system shown in FIG.
[0028]
The advantage of switching the detection wavelength for each inspection process will be described. FIG. 7 is an example of spectral reflection characteristics of a material used for manufacturing a multilayer thin film wiring substrate. Two examples of polyimide resin, one example of resist, and three examples of metal films were illustrated. The metal film has a relatively high reflectivity and is constant regardless of the wavelength, but the polyimide resin and the organic material of the resist have a high reflectivity for a long wavelength and a short wavelength. Has low reflectivity. For this reason, when a filter that selectively transmits a short wavelength is used, the metal film and the organic material can be separated and detected. Further, when the spectral reflectances of the polyimide resin and the resist are examined carefully, it can be seen that the wavelength at which the reflectance is minimized differs depending on the material. In order to maximize the detection contrast, detection may be performed at a wavelength having the minimum reflectance. Since the materials differ depending on the inspection process, it is better to switch the detection wavelength for each inspection process. This can be realized by the detection optical system shown in FIG.
[0029]
Next, the configuration of the defect determination processing system will be described with reference to FIG. The digital signal 801 from the preprocessing circuit 321 in FIG. 3 is binarized by the binarization circuit 802 and stored in the binary image memory 803. The binary image memory is composed of three memories 803a, b, and c. Since the linear sensor 317 is used to detect the image, the first scan image is stored in the memory 803a, the next scan image is stored in the memory 803b, and the third scan image is stored in the memory 803c. Images for the fourth scan are sequentially stored in the memory 803a. On the other hand, the magnetic disk device 805 stores a normal pattern shape for each inspection process in advance. When starting the inspection, the normal pattern of the inspection process is stored in the binary image memory 804 from the magnetic disk device 805. The detected image is read from the binary image memory 803 and the normal pattern is read from the binary image memory 804, the images are aligned with each other by the alignment circuit 806, and the non-matching portion is detected as a defect by the defect determination circuit 807. . The defect data is sent to the image processing computer 810 via the bus 808. Based on the defect data, the image processing computer 810 calls a detected image in the vicinity of the defect from the binary image memory 803, and determines whether the defect is a true defect or a false report by image processing by software. Furthermore, the size of the defect is also examined. Since there are three binary image memories 803, one is for storing signals from the binarization circuit 802, one is for calling to the alignment circuit 806, and one is from the image processing computer 810. Used for calling. The final defect data is sent from the image processing computer 810 to the control computer 809 and managed by the control computer.
[0030]
According to this embodiment, defect candidates are detected at high speed by hardware processing based on logic realized by an electric circuit, and then image processing optimum for each inspection process is performed on the defect candidates by software processing by an electronic computer. And true defects can be extracted.
[0031]
【The invention's effect】
According to the present invention, in the manufacturing process of the thin film multilayer wiring board, every time each layer is formed, the most recently formed layer is inspected, and after the defect is corrected, the next layer is formed. It is not necessary to inspect and correct the lower layer after completing the correction, and the yield can be improved.
[0032]
In addition, all inspection processes can be inspected with one inspection apparatus, and there is no need to prepare different inspection apparatuses for each inspection process.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a method for manufacturing a thin film multilayer wiring board according to the present invention.
FIG. 2 is a block diagram showing an embodiment of a thin film multilayer wiring board manufacturing system according to the present invention.
FIG. 3 is a block diagram of an appearance inspection apparatus according to the present invention.
FIG. 4 is an explanatory diagram of a detection optical system of an appearance inspection apparatus according to the present invention.
FIG. 5 is an explanatory diagram showing that illumination by a multiple ring light guide is effective for detecting a pattern inclined portion.
FIG. 6 is a cross-sectional view of a thin film multilayer wiring board in a certain process.
FIG. 7 is a characteristic diagram showing spectral reflectances of several types of materials.
FIG. 8 is a block diagram of a defect determination processing unit of the appearance inspection apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Multilayer ceramic substrate, 101 ... Pad, 102a ... Insulating film, 103 ... Photoresist, 104a ... Metal film, 105 ... Photoresist.

Claims (4)

  In the method of manufacturing a thin film multilayer substrate in which an insulating layer and a wiring layer are sequentially laminated, each time the insulating layer or the wiring layer is formed, the most recently formed layer is optically detected to check for pattern defects. A method of manufacturing a thin film multilayer substrate that inspects and corrects defects in the pattern based on position data of defects detected by the inspection, and the step of optically detecting the most recently formed layer includes The thin film multilayer substrate to be inspected is illuminated from multiple directions, and the illumination light quantity ratio from the multiple directions is changed for each inspection target layer according to the inclination angle of the step difference of the inspection target layer. In order to limit to the wavelength band where the difference between the reflectance of the layer and the reflectance of the lower layer formed immediately before it is large, the wavelength band limited for each layer to be inspected is changed, and the reflected light from the thin film multilayer substrate is specified. Detect from direction Method for manufacturing a thin-film multilayer substrate, wherein the door.   A method of manufacturing a thin film multilayer substrate in which a resist is applied, an insulating layer that forms a pattern by etching after exposure and development, and a wiring layer that is coated with the resist and exposed and developed, and then a pattern is formed by etching In the case of forming a new layer regardless of the insulating layer or the wiring layer, the resist pattern after exposure and development is optically detected, the most recently formed layer is optically detected, and the resist pattern A method of manufacturing a thin film multilayer substrate in which the defect of the resist pattern is corrected based on the position data of the defect detected by this inspection, wherein the most recently formed layer is optically detected. The step of detecting automatically is to illuminate the thin film multilayer substrate to be inspected from multiple directions, and the illumination light intensity ratio from the multiple directions is set to the inclination angle of the step of the inspection target layer. In order to limit to the wavelength band where the difference between the reflectivity of the most recently formed layer and the reflectivity of the lower layer formed immediately before it is different for each layer to be inspected, And the reflected light from the thin film multilayer substrate is detected from a specific direction. In the method for manufacturing a thin film multilayer substrate in which an insulating layer and a wiring layer are sequentially laminated, the manufacturing process for forming the insulating layer includes optically detecting a resist patterned to etch the insulating layer, After inspecting the presence or absence of defects in the pattern and correcting the defect in the resist pattern based on the position data of the defects detected by this inspection, the insulating layer is etched, and the etched insulating layer is removed. optically detected and inspected for defects of the pattern of the insulating layer, on the basis of the position data of the defects detected by the inspection, characterized in that to correct defects of the pattern of the insulating layer, the The manufacturing process for forming the wiring layer optically detects a resist patterned to etch the wiring layer, and the presence or absence of defects in the resist pattern. Examined, based on the position data of the defects detected by the inspection, after fixing a defect of the pattern of the resist, the wiring layer is etched, the wiring to detect the etched interconnect layers optically A method for manufacturing a thin-film multilayer substrate, in which the presence or absence of a defect in a layer pattern is inspected, and the defect in the pattern in the wiring layer is corrected based on the position data of the defect detected by the inspection, the etching being performed The step of optically detecting the insulating layer illuminates the thin film multilayer substrate to be inspected from multiple directions, and the illumination light quantity ratio from the multiple directions is determined according to the inclination angle of the step of the inspection target layer. In order to limit to the wavelength band where the difference between the reflectivity of the most recently formed layer and the reflectivity of the lower layer formed immediately before is changed for each layer to be inspected, the wavelength band to be limited for each layer to be inspected is changed. , Above thin Method for manufacturing a thin-film multilayer substrate and detecting the reflected light from the multilayer substrate from a particular direction.   The means for illuminating the thin film multilayer substrate to be inspected from multiple directions and the illumination light quantity ratio from multiple directions are adjusted for each inspection target layer according to the inclination angle of the step of the thin film multilayer substrate. The control means, the detection wavelength band limiting means for limiting the detection wavelength band, the reflectance of the layer formed most recently and the reflectance of the lower layer formed immediately before the wavelength band limited by the detection wavelength band limiting means Wavelength band adjusting means for adjusting the wavelength band for each layer to be inspected in order to set a band having a large difference, and the thin-film multilayer that has passed through the detection wavelength band limiting means in which the wavelength band is adjusted by the wavelength band adjusting means A pattern inspection apparatus comprising: means for detecting reflected light from a substrate from a specific direction; and means for extracting a pattern defect from the detected image.

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