JP2010216974A - Apparatus and method for irregularity inspection and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an irregularity inspection apparatus having satisfactory detection sensitivity without depending on the wavelength band of light even when the thickness of a film formed on a substrate is macroscopically gradually tilted and to provide an irregularity inspection method and a program. <P>SOLUTION: Light having different wavelength bands is irradiated to the film 92 formed in the upper surface of the substrate 9. Irregular images indicating variations in the film thickness of the film 92 are obtained on the basis of light of each wavelength band. By selecting regions containing irregularities from the irregularity images and composing each region, it is possible to obtain irregularity images in which film thickness irregularities are highly sensitively detected in the whole surface of the substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for inspecting film thickness unevenness of a film formed on an object.

  Conventionally, when a predetermined pattern is formed on the main surface of a glass substrate or the like for display devices (hereinafter simply referred to as “substrate”), a resist solution is applied to the main surface to form a resist film. To be done. The resist film formed on the main surface is required to have a uniform film thickness as much as possible because exposure, development, and the like are performed by subsequent processing. Therefore, a method for inspecting a portion where the film thickness is non-uniform or a portion where the film thickness fluctuates due to a minute unnecessary object (hereinafter generally referred to as “unevenness”) has been proposed.

  For example, Patent Document 1 irradiates a film formed on the main surface of a substrate with light of a plurality of wavelength bands, and measures the interference of the light reflected on the front surface and the back surface of the film, thereby reducing film thickness unevenness. An inspection method is disclosed.

JP 2006-292487 A

  However, the film formed on the substrate may have a gentle slope depending on the formation method. In such a case, according to the method of Patent Document 1, there is a possibility that a portion with poor inspection sensitivity may occur in the substrate surface depending on the wavelength band of light.

  The present invention has been made in view of the above problems, and an object thereof is to perform a highly sensitive inspection over the entire surface of a substrate.

  According to the first aspect of the present invention, in the unevenness inspection apparatus for inspecting the film thickness unevenness of the film formed on the substrate, light is applied to the substrate on which the light transmissive film is formed on the main surface. A light irradiating unit, an imaging unit that captures an image formed by reflection of light irradiated by the light irradiating unit on the front and back surfaces of the film, and light from the light irradiating unit to the imaging unit An optical filter that is disposed on the road and transmits light of predetermined first and second wavelength bands, and a first image and a second wavelength of light of the first wavelength band that are imaged by the imaging means Unevenness detecting means for detecting the position and shape of unevenness from the second image by the band light, and dividing means for dividing the first image and the second image in which the unevenness is detected by the unevenness detecting means into corresponding regions. And divided by the dividing means Based on the unevenness in each region comprises one of the image divided from the first image or the second image, an image selection means for a representative image in the region.

  According to a second aspect of the present invention, the unevenness inspection apparatus according to the first aspect further includes a synthesizing unit that synthesizes the unevenness inspection image by arranging representative images selected by the image selection unit.

  According to a third aspect of the present invention, in the unevenness inspection apparatus according to the first or second aspect, the region divided by the dividing unit is one of repeated patterns formed on the substrate.

  According to a fourth aspect of the present invention, in the unevenness inspection apparatus according to the first or second aspect, the region divided by the dividing unit is a region including the unevenness detected by the unevenness detecting unit.

  According to a fifth aspect of the present invention, in the unevenness inspection apparatus according to any one of the first to fourth aspects, the unevenness detection means is included in a predetermined detection area of the first image and the second image. Unevenness is detected based on the difference between the maximum and minimum pixel values.

  According to a sixth aspect of the present invention, there is provided a non-uniformity inspection method for inspecting a nonuniformity in film thickness of a film formed on a substrate with respect to a substrate having a light-transmitting film formed on a main surface thereof. An imaging step of irradiating light in the second wavelength band and capturing an image formed by light reflected by the front and back surfaces of the film; a first image by light in the first wavelength band; A non-uniformity detecting step of detecting the position and shape of the non-uniformity from the second image by the light of the second wavelength band, a dividing step of dividing the first image and the second image into corresponding regions, and the divided And an image selection step in which one of the images divided from the first image and the second image is used as a representative image in the region based on the unevenness in each region.

  The invention described in claim 7 further includes a combining step of combining the unevenness inspection images by arranging the representative images selected in the image selection step in the unevenness inspection method according to claim 6.

  The invention described in claim 8 is the unevenness inspection method according to claim 6 or 7, wherein the region divided in the dividing step is one of the repeated patterns formed on the substrate.

  According to a ninth aspect of the present invention, in the unevenness inspection method according to the sixth or seventh aspect, the region divided in the dividing step is a region including the unevenness detected in the unevenness detecting step. .

  According to a tenth aspect of the present invention, in the unevenness inspection method according to any one of the sixth to ninth aspects, the unevenness detection step includes a predetermined detection region of the first image and the second image. Unevenness is detected based on the difference between the maximum and minimum pixel values.

  The invention according to claim 11 is a program that causes a computer to inspect the film thickness unevenness of a light-transmitting film formed on an object, and the computer executes the program by a) A step of acquiring an image of a plurality of wavelength bands captured by irradiating light on a film formed on the object; and b) detecting a position and a shape of unevenness from the images of the plurality of wavelength bands. And c) dividing the image into corresponding regions, comparing unevenness in the regions, and selecting one of the divided images as a representative image in the region. Let

  In the present invention, film thickness unevenness can be detected with high sensitivity on the entire surface of the substrate without depending on the film thickness. In particular, in the inventions according to the second and seventh aspects, it is possible to obtain an uneven image on the entire surface of the substrate by a simple method. In particular, in the inventions according to the third and eighth aspects, it is possible to easily detect film thickness unevenness over the entire surface of the substrate on which the repeated pattern is formed. In particular, in the inventions according to the fourth and ninth aspects, it is possible to detect unevenness with high sensitivity for a substrate having unevenness in a part of the substrate. In particular, in the inventions according to claims 5 and 10, unevenness can be detected by a simple method.

It is a figure which shows the structure of the nonuniformity inspection apparatus which concerns on 1st Embodiment. 3 is a diagram illustrating a configuration of a control unit 6. FIG. It is a block diagram which shows the function structure which the calculating part 61 implement | achieves. It is a figure which shows the flow of a test | inspection in the nonuniformity inspection apparatus which concerns on 1st Embodiment. It is a schematic diagram which divides | segments a 1st image and a 2nd image. It is a figure which shows a 1st image. It is a figure which shows a 2nd image. It is a figure which shows the relationship between a film thickness and a reflectance. It is a figure which shows the relationship between a film thickness and the fluctuation | variation of a reflectance. It is a figure which shows the synthesized image. It is a figure which shows the flow of an inspection in the nonuniformity inspection apparatus which concerns on 2nd Embodiment. It is a figure which shows the 1st image based on 2nd Embodiment. It is a figure which shows the 2nd image based on 2nd Embodiment. It is a figure which shows the synthesized image based on 2nd Embodiment.

  FIG. 1 is a diagram showing a configuration of an unevenness inspection apparatus 1 according to the first embodiment of the present invention. The unevenness inspection apparatus 1 holds a substrate 9 on which a film 92 is formed on a main surface 91 (hereinafter referred to as “upper surface 91”) with the upper surface 91 facing upward (the (+ Z) side in FIG. 1). The stage 2, the light emitting part 3 that emits light toward the film 92 on the upper surface 91 of the substrate 9 held by the stage 2, and the light emitted from the light emitting part 3 and reflected by the film 92 A light receiving unit 4 that receives light, a wavelength band switching mechanism 5 that is disposed between the substrate 9 and the light receiving unit 4 and switches the wavelength band of light received by the light receiving unit 4, and a light emitting unit 3 that receives the stage 2. Film thickness unevenness of the film 92 based on the intensity distribution (distribution corresponding to the region of the upper surface 91) of the light received by the moving mechanism 21 that moves relative to the portion 4 and the wavelength band switching mechanism 5 Are provided with a control unit 6 and a display unit 7 for controlling the configuration. In FIG. 1, for convenience of illustration, a part of the wavelength band switching mechanism 5 is shown in cross section.

  The (+ Z) side surface of the stage 2 is preferably black matte. The moving mechanism 21 has a configuration in which a ball screw (not shown) is connected to a motor 211, and the stage 211 moves along the upper surface 91 of the substrate 9 along the guide 212 by rotating the motor 211 in FIG. Move in the direction.

  The light emitting section 3 extends in the Y direction in FIG. 1 perpendicular to the movement direction of the halogen lamp 31 and the stage 2 that are white light (that is, light including light in all wavelength bands in the visible region). A cylindrical quartz rod 32 and a cylindrical lens 33 extending in the Y direction are provided. In the light emitting part 3, a halogen lamp 31 is attached to the end on the (+ Y) side of the quartz rod 32, and the light incident on the quartz rod 32 from the halogen lamp 31 is linear light extending in the Y direction (that is, The light beam cross-section is converted to light that is long in the Y direction), is emitted from the side surface of the quartz rod 32, and is guided to the upper surface 91 of the substrate 9 through the cylindrical lens 33. In other words, the quartz rod 32 and the cylindrical lens 33 convert the light from the halogen lamp 31 into linear light along the upper surface 91 of the stage 2 and perpendicular to the moving direction to convert the film 92 on the upper surface 91 of the substrate 9. It is an illumination optical system that leads to

  In FIG. 1, the optical path from the light emitting part 3 to the substrate 9 is indicated by a one-dot chain line (the same applies to the optical path from the substrate 9 to the light receiving part 4). A part of the light emitted from the light emitting portion 3 and incident on the film 92 on the upper surface 91 of the substrate 9 with an inclination (that is, at an incident angle larger than 0 °) is on the upper surface 91 of the substrate 9. Is reflected on the upper surface of the film 92 on the (+ Z) side. The film 92 is light transmissive to the light from the light emitting part 3, and the light that has not been reflected by the upper surface of the film 92 out of the light from the light emitting part 3 passes through the film 92. Reflected by the upper surface 91 of the substrate 9 (that is, the lower surface of the film 92). In the unevenness inspection apparatus 1, interference light (hereinafter simply referred to as “reflected light”) between the light reflected by the upper surface of the film 92 and the light reflected by the upper surface 91 of the substrate 9 is a wavelength band. The light enters the light receiving unit 4 via the switching mechanism 5.

  The light receiving unit 4 (corresponding to the image pickup means) includes a line sensor 41 in which a plurality of light receiving elements (CCDs) are linearly arranged in the Y direction, and an optical path from the substrate 9 to the line sensor 41. In addition, a condensing lens 42 is provided between the line sensor 41 and the wavelength band switching mechanism 5. The condenser lens 42 is reflected by a film 92 in a linear irradiation region (hereinafter referred to as “linear irradiation region”) that is emitted from the light emitting unit 3 and extends in the Y direction on the upper surface 91 of the substrate 9. Of the subsequent linear light, the light in the selected wavelength band that has passed through the optical filter 51 is condensed toward the line sensor 41. The line sensor 41 receives the light in the selected wavelength band that is condensed and imaged by the condenser lens 42, and calculates the intensity distribution of the received light (that is, the distribution in the Y direction of the output value from each CCD). Obtain and output to the control unit 6. In the unevenness inspection apparatus 1, the intensity distribution of the reflected light from the film 92 formed on the upper surface 91 of the substrate 9 is repeatedly acquired by the line sensor 41 during the movement of the substrate 9 and the stage 2.

  The wavelength band switching mechanism 5 is a disk-like shape that holds a plurality of optical filters (for example, interference filters having a half-value width of 10 nm) 51 and a plurality of optical filters 51 that selectively transmit light of a plurality of different narrow wavelength bands, respectively. And a filter rotation motor 53 that is attached to the center of the filter wheel 52 and rotates the filter wheel 52. The filter wheel 52 is arranged so that the normal direction thereof is parallel to the optical path from the substrate 9 to the light receiving unit 4.

  FIG. 2 is a diagram illustrating a configuration of the control unit 6. The control unit 6 includes a calculation unit 61, a fixed disk 62, an interface (I / F) unit 63, and an image storage unit 64.

  The calculation unit 61 controls the devices constituting the unevenness inspection apparatus such as the stage 2 and the light irradiation unit 3 via the I / F unit 63. Further, the display unit 61 executes the program 65 stored in the fixed disk 62 and performs unevenness inspection as will be described later. The image storage unit 64 receives the output from the line sensor 41 and temporarily stores a two-dimensional image of the upper surface 91 of the substrate 9. Specifically, the control unit 6 is a computer or the like, and is connected to the display unit 7 or an input device (not shown).

  FIG. 3 is a block diagram illustrating a functional configuration realized by the calculation unit 61, the fixed disk 62, and the like when the calculation unit 61 operates according to the program 65. The calculation unit 61 functions as an image extraction function 611, an image selection function 612, and an image composition function 613, and displays the calculation result on the display unit 7. All or part of these may be performed by a dedicated electronic circuit.

Next, the flow of inspection of film thickness unevenness by the unevenness inspection apparatus 1 will be described. FIG. 4 is a diagram showing a flow of inspection by the unevenness inspection apparatus 1. When the film thickness unevenness of the film 92 on the upper surface 91 of the substrate 9 is inspected by the unevenness inspection apparatus 1 shown in FIG. 1, first, based on characteristics such as the material and film thickness of the film 92 to be inspected. A first wavelength band (for example, the center wavelength is 550 nm and the half width is 10 nm) is selected, and the first optical filter 51 having the transmission wavelength band is arranged on the optical path.
Specifically, the control unit 6 gives a control command to the filter rotation motor 53 and rotates the motor by a predetermined angle, so that the optical axis between the upper surface 91 of the substrate 9 and the light receiving unit 4 is changed to the first position. One optical filter 51 is arranged. Thereafter, the substrate is placed on the stage by a substrate transfer device (not shown) (step S1).

Next, an image in the first wavelength band is acquired (step S2).
Specifically, the control unit 6 gives a command to the stage 2 and moves the stage 2 to an inspection start position indicated by a solid line in FIG. Then, the inspection indicated by a two-dot chain line in FIG. 1 is completed in a state where linear light is irradiated from the light emitting portion 3 onto the upper surface 91 of the substrate 9 at a predetermined incident angle (60 ° in this embodiment). The stage 2 is moved to the position. The light from the light emitting unit 3 is reflected by the upper surface 91 of the substrate 9 and passes through the optical filter 51 that transmits the first wavelength band, so that only light in a specific wavelength band is extracted, and then the light receiving unit. 4 leads to. In the light receiving unit 4, the light in the first wavelength band after reflection on the upper surface 91 of the substrate 9 is received by the line sensor 41 via the condenser lens 42, and the first reflected light from the linear irradiation region on the substrate 9 is received. An intensity distribution in one wavelength band is acquired. The intensity distribution in the first wavelength band stored in the image storage unit 64 of the control unit 6 can be handled as a first image by being stored in order as continuous data.

Subsequently, an image in the second wavelength band (for example, the center wavelength is 575 nm and the half width is 10 nm) is acquired (step S3).
Specifically, the control unit 6 gives a control command to the filter rotation motor 53 and rotates the motor by a predetermined angle, so that the optical axis between the upper surface 91 of the substrate 9 and the light receiving unit 4 is changed to the first position. Two optical filters 51 are arranged. Then, similarly to step S2 described above, by moving the stage 2 while irradiating the linear light from the light emitting unit 3, the light receiving unit 4 acquires the intensity distribution in the second wavelength band. Similar to the first image, the intensity distribution in the second wavelength band stored in the image storage unit 64 of the control unit 6 can be handled as the second image by being stored in order as continuous data.

Next, unevenness detection is performed on the first image and the second image acquired in step S2 and step S3 (step S4).
Specifically, the control unit 6 detects and stores unevenness by detecting changes in the pixel values of the first image and the second image stored in the image storage unit 64.

  As shown in FIG. 5, a periodic pattern surface 93 is formed in advance on the substrate 9 to be a single panel in subsequent processing. FIG. 5 shows that six periodic pattern surfaces 93 are formed.

  In the first image, a part of the image where the light intensity is smaller than the other part is observed. This indicates a portion having a thickness at which the light reflected on the upper surface of the film 92 by the wavelength band of light and the light reflected on the lower surface of the film 92 (= the upper surface of the substrate 91) cancel each other.

  Here, when the film thickness changes gently, each pixel value in a predetermined region (for example, eight pixels adjacent to the target pixel) does not change greatly. However, in a region where the film thickness changes abruptly (a region where unevenness occurs), the pixel value changes abruptly. Therefore, nonuniformity can be detected by obtaining the difference between the maximum value and the minimum value of the pixel values included in the predetermined area.

  The control unit 6 determines the region where the unevenness is generated, recognizes it as the dot-shaped unevenness 931a and the stripe unevenness 932a based on the shape, and stores them in the image storage unit 64.

  FIG. 6 is a diagram illustrating the first image after unevenness is detected in step S4. In the light of the first wavelength band forming the first image, the unevenness on the upper side of the substrate 9 in FIG. 6 is detected, but the lower side is hardly detected.

  Subsequently, the control unit 6 detects unevenness in the second image as in the first image.

  FIG. 7 is a diagram illustrating the second image after the detection of unevenness. In the light of the second wavelength band forming the second image, the lower side unevenness (931b, 932b) of the substrate 9 in FIG. 6 is detected, but the upper side is hardly detected.

  FIG. 8 is a diagram showing the relationship between the film thickness of the film 92 and the reflectance 101. The reflectance 101 of the film 92 varies with periodicity with respect to the variation in film thickness. FIG. 9 is a diagram showing a change in the reflectance 101 when the film thickness of the film 92 is changed by 1 nm. As shown in FIGS. 5 and 6, in the vicinity of the maximum point and in the vicinity of the minimum point of the reflectance 101, the variation of the reflectance 101 with respect to the variation of the film thickness becomes very small. For this reason, when the variation in the film thickness is slight, the intensity of the light of the received image hardly varies, and the accuracy of detecting the unevenness (that is, the variation in the film thickness) is lowered. Hereinafter, a region having a film thickness in which the rate of change in the reflectance 101 with respect to the film thickness variation is extremely small is referred to as a “low sensitivity region”. Needless to say, the reflectance 101 is a ratio between the intensity of light emitted from the light emitting unit 3 and the intensity of light received by the light receiving unit. Further, in a portion where the reflectance is high, the pixel value representing the intensity of received light as a signal also increases.

Next, the first image and the second image in which the unevenness is detected in step S4 are divided into corresponding regions.
Specifically, the control unit 6 divides the first image and the second image stored in the image storage unit 64 for each corresponding region. In the present embodiment, an example in which the periodic pattern surface 93 to be formed on the substrate is divided as one unit region is shown.

  First, the control unit 6 discriminates the periodic pattern surface 93 from the first image and the second image, and divides by forming a dividing line 911 between the adjacent periodic pattern surfaces 93. In the divided images, the peripheral gaps are removed, and six images of only the periodic pattern surface 93 are formed, i.e., 12 images in total.

  The determination of the periodic pattern surface 93 may be performed based on image processing or may be based on a CAD (Computer Aided Design) drawing at the design stage of the substrate 9.

Next, the amount of unevenness detected in each region is compared (step S6).
Specifically, the control unit 6 detects the number of detected irregularities (frequency) included in each area divided in step S5, and compares it for each area at a corresponding position in the first image and the second image. I do.

In contrast to 93a, which is an area surrounded by a broken line in FIG. 6, 93b, which is an area surrounded by a broken line in FIG. 7, is an area at a corresponding position. The control unit 6 detects the frequency of unevenness detected in 93a and 93b and performs comparison.
When the frequency of unevenness detected in the first image 93a is high, 93a is selected as a representative image at that position (step S7).
When the frequency of unevenness detected in the second image 93b is high, 93b is selected as the representative image at that position (step S8).
Then, a representative image at each position is selected by sequentially comparing the corresponding areas.

Subsequently, image composition is performed (step S9).
By performing the above-described steps S6 to S8 for all the divided areas, representative images for images in all the areas are selected. The representative image is arranged again at the same position as the divided image, and the images are combined to form a third image with a large number of detected irregularities in all regions.

  FIG. 10 is a view showing a synthesized image. In the synthesized image, the number of detected irregularities is large on all periodic pattern surfaces. The synthesized image is displayed on the display unit 7 so that the operator can visually recognize it.

  Through the above steps, even when the film thickness of the film 92 on the upper surface 91 of the substrate 9 becomes a low sensitivity region depending on the wavelength band to be measured, unevenness is recognized with high accuracy in the entire region of the substrate 9. Is possible.

Next, the unevenness inspection apparatus 1a according to the second embodiment of the present invention will be described.
The unevenness inspection apparatus 1a differs from the unevenness inspection apparatus 1 according to the first embodiment only in the method of dividing the region. Therefore, the same code | symbol is attached | subjected regarding the same structure and description is abbreviate | omitted.

  FIG. 11 is a diagram showing a flow of inspection by the unevenness inspection apparatus 1a. Steps S1 to S4 are the same as those in the unevenness inspection apparatus 1, and thus description thereof is omitted.

  FIG. 12 is a diagram showing the substrate 9a imaged by light in the first wavelength band. In the light of the first wavelength band, the substrate 9a is observed bright (high reflectivity), and streaky unevenness (hereinafter referred to as streak unevenness 94) is observed dark (low reflectivity). Show.

  Further, in the light of the first wavelength band, it is observed that the stripe unevenness 94 is cut in the downward direction in FIG. 12, but this is a low sensitivity region in the light of the first wavelength band. It shows that.

  FIG. 13 is a diagram showing the substrate 9a imaged by light in the second wavelength band. In the light of the second wavelength band, the substrate 9a is observed dark, and the stripe unevenness 94 is observed brightly. In the upward direction in FIG. 13, the region is a low sensitivity region, and the stripe unevenness 94 can hardly be observed.

The unevenness inspection apparatus 1a according to the second embodiment first selects a background image from the acquired images (step S51).
Specifically, the control unit 6 selects one of the first image and the second image stored in the image storage unit 64 as a background image. This may be based on the detection frequency of unevenness or simply determined by the acquisition order. Here, the case where the first image is selected will be described below.

Next, an uneven area is extracted (step S61).
Specifically, the control unit 6 extracts a mura region for the second image that is not selected as the background image in step S51. Since the position and shape of the unevenness are detected in step S4, the areas detected as unevenness in the second image are selected, and the unevenness image is extracted.

Thereafter, the extracted unevenness is combined with the background image (step S71).
Specifically, the control unit 6 synthesizes the unevenness image extracted in step S61 with the background image (first image in the example). When unevenness is detected in the background image by combining the images, the extracted uneven images are displayed in a superimposed manner. This is because the region of the background image (first image) corresponding to the region detected as unevenness in the second image is divided from the other regions, and then the second image is selected as the representative image of the region. Means that.

  Then, the steps S61 and S71 are repeated for all the uneven regions included in the second image (step S81), whereby the unevenness detected in the second image is displayed on the background image (first image). Images are synthesized.

  FIG. 14 is a view showing a synthesized image. The background of the first image is selected as the background image, and the first image unevenness 94 and the second image unevenness 95 are combined and displayed. The synthesized image is displayed on the display unit 7 so that the operator can visually recognize it.

  As described above, even in the unevenness inspection apparatus 1a, unevenness can be reliably recognized in the entire region of the substrate, as in the first embodiment.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  Further, for example, the stage holding the substrate 9 may be moved relative to the light emitting unit 3, the light receiving unit 4, and the wavelength band switching mechanism 5, and the stage is fixed, and the light emitting unit 3, the light receiving unit 4 and The wavelength band switching mechanism 5 may be moved while being fixed to each other.

  In the unevenness inspection apparatus according to the above embodiment, when the light emitted from the halogen lamp 31 includes light in a wavelength band that adversely affects the film 92 formed on the substrate 9, A filter or the like that does not transmit light is provided on the optical path from the halogen lamp 31 to the substrate 9. In addition, when the film 92 on the upper surface 91 of the substrate 9 is transparent to infrared light, a light source that emits infrared light may be provided in the light emitting unit 3 instead of the halogen lamp 31 that emits white light.

  In the light emitting unit 3, a fiber array in which a plurality of optical fibers are linearly arranged is provided in place of the quartz rod 32, and light from the halogen lamp 31 is converted into linear light by passing through the fiber array. Also good. Further, instead of the halogen lamp 31 and the quartz rod 32, a plurality of light source elements arranged in a straight line may be provided as a light source that emits linear light.

  If the wavelength band switching mechanism 5 is disposed on the optical path from the light emitting unit 3 to the line sensor 41, it is not always necessary to be disposed between the substrate 9 and the light receiving unit 4. For example, the light emitting unit 3 may be disposed on the optical path from 3 to the substrate 9.

  In the above embodiment, the images are synthesized by comparing the images in the two wavelength bands. However, by comparing the images in the more wavelength bands, the unevenness is inspected with higher sensitivity. be able to.

  The unevenness inspection apparatus according to the above embodiment may be used for detection of film thickness unevenness of other films other than the resist film, for example, an insulating film or a conductive film formed on the substrate 9. It may be formed by a method other than coating of the coating solution, for example, vapor deposition, chemical vapor deposition (CVD), sputtering, or the like. In addition, the unevenness inspection apparatus may be used for inspection of film thickness unevenness of a film formed on another substrate such as a semiconductor substrate.

  The present invention relates to a semiconductor wafer, a glass substrate for photomask, a glass substrate for liquid crystal display, a glass substrate for plasma display, a substrate for FED (Field Emission Display), a substrate for optical disk, a substrate for magnetic disk, a substrate for magneto-optical disk, etc. The present invention can be applied to a non-uniformity detection apparatus, a non-uniformity detection method, and a program for performing non-uniformity detection that detect film thickness non-uniformity (coating nonuniformity) that occurs when a coating liquid is applied to the entire surface of the substrate.

1, 1a Unevenness inspection apparatus 2 Stage 3 Light emitting unit 4 Light receiving unit 5 Wavelength band switching mechanism 6 Control unit 9, 9a Substrate 61 Calculation unit 65 Program 91 Upper surface 92 Film 93 Periodic pattern surface 931a, 931b Dot-shaped unevenness 932a, 932b Streak Unevenness 94, 95 Unevenness 611 Region extraction function 612 Image selection function 613 Image composition function S1 to S9, S51 to S81 Steps

Claims (11)

In the unevenness inspection apparatus that inspects the film thickness unevenness of the film formed on the substrate,
A light irradiation unit for irradiating light on a substrate having a light-transmitting film formed on the main surface;
An imaging unit that captures an image formed by the light irradiated by the light irradiation unit being reflected by the front and back surfaces of the film;
An optical filter that is disposed on an optical path from the light irradiating unit to the imaging unit and that transmits light in predetermined first and second wavelength bands;
Unevenness detecting means for detecting the position and shape of unevenness from the first image by the light of the first wavelength band and the second image by the light of the second wavelength band, which are imaged by the imaging means;
A dividing unit that divides the first image and the second image in which the unevenness is detected by the unevenness detecting unit into corresponding regions;
An image selection unit that uses one image divided from the first image or the second image as a representative image in the region based on unevenness in each region divided by the dividing unit;
A nonuniformity inspection apparatus comprising:
The unevenness inspection apparatus according to claim 1,
An unevenness inspection apparatus, further comprising: a combining unit that combines the unevenness inspection images by arranging representative images selected by the image selection unit.
The unevenness inspection apparatus according to claim 1 or 2,
The unevenness inspection apparatus, wherein the region divided by the dividing unit is one of repeated patterns formed on the substrate.
The unevenness inspection apparatus according to claim 1 or 2,
The unevenness inspection apparatus characterized in that the area divided by the dividing means is an area including unevenness detected by the unevenness detecting means.
In the nonuniformity inspection apparatus in any one of Claims 1-4,
The unevenness detection device detects unevenness based on a difference between a maximum value and a minimum value of pixel values included in a predetermined detection area of the first image and the second image. .
In the unevenness inspection method for inspecting the film thickness unevenness of the film formed on the substrate,
An image formed by light reflected on the front and back surfaces of the film is irradiated with light in the first and second wavelength bands on a substrate having a light-transmitting film formed on the main surface. An imaging process for imaging;
A non-uniformity detecting step of detecting the position and shape of non-uniformity from the first image by the light of the first wavelength band and the second image by the light of the second wavelength band;
A dividing step of dividing the first image and the second image into corresponding regions;
Based on the unevenness in each of the divided regions, an image selection step in which one of the images divided from the first image or the second image is a representative image in the region;
An unevenness inspection method comprising:
The unevenness inspection method according to claim 6,
An unevenness inspection method, further comprising a combining step of combining the unevenness inspection images by arranging representative images selected in the image selection step.
In the unevenness inspection method according to claim 6 or 7,
The unevenness inspection method, wherein the region divided in the dividing step is one of repetitive patterns formed on the substrate.
In the unevenness inspection method according to claim 6 or 7,
The unevenness inspection method, wherein the region divided in the dividing step is a region including unevenness detected in the unevenness detection step.
In the nonuniformity inspection method in any one of Claims 6-9,
In the unevenness detecting step, unevenness is detected based on a difference between a maximum value and a minimum value of pixel values included in a predetermined detection area of the first image and the second image. .
A program for causing a computer to inspect the film thickness unevenness of a light-transmitting film formed on an object, and executing the program by the computer
a) obtaining an image of a plurality of wavelength bands, which is imaged by irradiating light on a film formed on the object;
b) detecting a position and shape of unevenness from an image of the plurality of wavelength bands;
c) dividing the image into corresponding regions, comparing unevenness in the regions, and selecting any one of the divided images as a representative image in the regions;
A program characterized by having executed.

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