JP4248364B2 - Film thickness inspection system for three primary color layers - Google Patents

Description

  The present invention relates to a film thickness inspection apparatus, and more particularly to an apparatus for inspecting film thickness uniformity for a substrate having a colored layer composed of three primary colors.

  Display members such as color filters for liquid crystal displays, plasma display panels, and organic EL display substrates have a structure in which several layers of films are coated on a transparent substrate such as glass. For example, a color filter for a liquid crystal display has a structure in which a black matrix layer and colored layers of three primary colors of RGB are coated on a glass substrate. Usually, the three primary color layers are formed by applying a material by spin coating or die coating and then performing patterning using photolithography. For this reason, the non-uniformity of film thickness (so-called film thickness unevenness) generated during the spin coating or die coating process remains as it is in each colored layer after patterning and causes defects.

  For this reason, in order to minimize the time and material loss in the process of manufacturing the display member, the film thickness unevenness of each lot is reduced at an early stage immediately after the material for constituting each colored layer is applied. It is desirable to find and deal with it. Therefore, usually, a measure is taken in which a film thickness inspection apparatus is installed immediately after an apparatus (so-called coater) that performs spin coating or die coating, and whether or not there is film thickness unevenness in an in-line process.

As inspection equipment for precise inspection of minute film thickness, the film to be inspected is irradiated with light from a light source that emits coherent light, such as a low-pressure sodium lamp, a halogen lamp, a helium lamp, or a metal halide lamp. Many types of devices that use interference of light reflected on the upper and lower surfaces of the film are used. For example, Patent Document 1 below discloses a film thickness inspection apparatus that uses a light source including a plurality of intensity peaks having a half-width of a spectrum of 30 nm or less.
Japanese Patent No. 3114972

  As described above, in order to accurately inspect a minute film thickness, it is common to use an interference phenomenon using coherent light. In particular, when the object to be inspected is a color display member, it is necessary to inspect the film thickness for each of the RGB primary color layers, so a light source that can be used in common for the inspection of these three primary color layers is required. Become. For example, the emission spectrum of a low-pressure sodium lamp is distributed in the vicinity of 590 nm and can be used for the inspection of the red (R) and green (G) colored layers, but the blue (B) colored layer. However, since the absorption rate is high, sufficient test results cannot be obtained. On the other hand, since the wavelength range of the metal halide lamp is continuously distributed in the visible light region, it is used as a light source that can be used in common for the inspection of the colored layers of the three primary colors by combining with a band pass filter. be able to. However, since the metal halide lamp is a very expensive light source, the cost of the entire film thickness inspection apparatus increases.

  The size of display devices has been increasing year by year, and display members to be inspected have also become larger and the inspection area has been increasing. In order to deal with such an inspection object having a large area, the light source incorporated in the film thickness inspection apparatus is also required to have a function of irradiating light to a certain wide area. For this reason, in the case of a conventional film thickness inspection apparatus using a metal halide lamp or the like as a light source, it is necessary to incorporate a large metal halide lamp or a plurality of metal halide lamps arranged side by side, which increases the cost. Will occur.

  Therefore, an object of the present invention is to provide a low-cost film thickness inspection apparatus that can perform film thickness inspection for each of the three primary color layers on a relatively large inspection object.

(1) A first aspect of the present invention is a film thickness inspection apparatus having a function of inspecting the uniformity of film thickness for the colored layers of the three primary colors RGB using interference of light .
A transport device that transports an inspection target substrate having a colored layer in the X-axis direction so that its main surface is parallel to the XY plane when an XY two-dimensional coordinate system is defined;
A line configured by arranging a plurality of light receiving elements in a direction parallel to the Y axis, and arranged so that a linear visual field region on the inspection target substrate transported by the transport device can be imaged obliquely from above A sensor,
A straight tube type three-wavelength fluorescent lamp arranged so that the longitudinal direction thereof is parallel to the Y axis so that at least the linear visual field region can be illuminated obliquely from above;
A bandpass filter that is disposed between the linear visual field region and the line sensor and selectively transmits a predetermined range of light within the transmission spectrum region of the colored layer to be inspected;
Combining multiple one-dimensional images captured by the line sensor, the thickness distribution of the colored layer on the substrate to be inspected is an interference fringe pattern of the reflected light from the upper surface and the reflected light from the lower surface of the colored layer. An image processing device for creating a two-dimensional image shown;
Provided,
The three-wavelength fluorescent lamp has its spectrum having three peaks that overlap the transmission spectrum region of each colored layer of the three primary colors RGB,
As the band-pass filter, three types of band-pass filters that selectively transmit light in the wavelength ranges corresponding to the three peaks are prepared .

(2) According to a second aspect of the present invention, in the film thickness inspection apparatus for the three primary color layers according to the first aspect described above,
An optical filter that selectively transmits light in the range of 430 to 450 nm, an optical filter that selectively transmits light in the range of 535 to 555 nm, and an optical filter that selectively transmits light in the range of 600 to 620 nm The three types of band-pass filters are configured such that they can be selectively attached between the linear visual field region and the line sensor.

(3) According to a third aspect of the present invention, in the film thickness inspection apparatus for the three primary color layers according to the first or second aspect described above,
A filter for cutting light in a short wavelength region, which is a photosensitive band of a photosensitive material layer formed on a substrate to be inspected, is provided between a three-wavelength fluorescent lamp and a linear visual field region. It is.

(4) A fourth aspect of the present invention is the film thickness inspection apparatus for the three primary color layers according to the first to third aspects described above,
The bandpass filter is arranged so that the normal line standing on its main surface is inclined with respect to the optical axis of the line sensor, so that the reflected light on the surface of the bandpass filter does not enter the linear visual field region. is there.

(5) According to a fifth aspect of the present invention, in the film thickness inspection apparatus for the three primary color layers according to the first to fourth aspects described above,
The angle formed by the optical axis of the line sensor and the main surface of the substrate to be inspected is set to 30 ° to 70 °.

  According to the film thickness inspection apparatus for the three primary color layers according to the present invention, a straight tube type three-wavelength fluorescent lamp is used as a light source to illuminate a linear field region on the inspection target substrate. Since the reflected light from the light is observed by the line sensor through a predetermined bandpass filter, it is possible to inspect the film thickness of each colored layer of the three primary colors for a relatively large inspection object. Further, since a straight tube type three-wavelength fluorescent lamp is used as the light source, the cost can be reduced.

  Hereinafter, the present invention will be described based on the illustrated embodiments. First, an inspection principle of a general film thickness inspection apparatus using light interference will be briefly described with reference to a side view of FIG. Now, it is assumed that the colored layer 11 is formed on the inspection target substrate 10 as shown in the figure. At this time, consider a case where illumination light A having a predetermined wavelength is irradiated obliquely from above. In this case, a part of the illumination light A is reflected by the upper surface of the colored layer 11 and goes obliquely upward as reflected light B1, and another part is the lower surface of the colored layer 11 (the colored layer 11 and the substrate 10). And is reflected obliquely upward as reflected light B2. Accordingly, when these reflected lights B1 and B2 are observed from the upper right side of the figure, a predetermined interference fringe is observed due to the interference between the two.

  Here, if the colored layer 11 is a layer having a completely uniform film thickness, the observed interference fringes are also completely uniform. However, when film thickness unevenness occurs in the colored layer 11, an interference fringe pattern corresponding to the contour line appears. For example, as shown in the side sectional view of FIG. 2A, a substrate 10 to be inspected on which a colored layer 11 having a partially raised film thickness unevenness is formed is inspected according to the principle shown in FIG. Then, an interference fringe pattern as shown in the plan view of FIG. 2 (b) is observed, and the film thickness distribution is obtained as a contoured two-dimensional image. Therefore, if a two-dimensional image showing such an interference fringe pattern is presented on the display screen, the operator in charge of the inspection can check the film of the colored layer 11 formed on the inspection target substrate 10 based on the two-dimensional image. Thickness unevenness can be recognized, and quality can be determined.

  When performing a film thickness inspection based on such a principle, first, as the illumination light A, it is necessary to use light in a wavelength region that transmits the colored layer 11. This is because when the wavelength of the illumination light A is the absorption region of the colored layer 11, the light is absorbed in the colored layer 11 and the reflected light B2 cannot be obtained. Further, in order to obtain an interference fringe pattern, the reflected lights B1 and B2 need to be coherent light and need to be light in a narrow wavelength range (ideally monochromatic light). .

  A typical light source for obtaining monochromatic light is a laser light source. However, since light generated by a normal laser light source is beam-like light, it is suitable for use in a film thickness inspection apparatus such as the present invention. Not. On the other hand, a low-pressure sodium lamp has long been known as a general-purpose light source that generates light having a narrow wavelength range close to monochromatic light, and is also used in a conventional film thickness inspection apparatus. However, it is unsuitable for use in a film thickness inspection apparatus for the three primary color layers as in the present invention. This is because the emission spectrum of the low-pressure sodium lamp is distributed around 590 nm as shown in the graph of FIG. 3, which is sufficient for the transmission spectra (not shown) of the red (R) and green (G) colored layers. Although overlapping, the overlap with the transmission spectrum of the blue (B) colored layer is extremely small and cannot be used for the inspection of the blue colored layer. That is, in the principle diagram shown in FIG. 1, when the light from the low-pressure sodium lamp is used as the illumination light A, when the colored layer 11 is a blue colored layer, most of it is absorbed in the colored layer 11, Effective reflected light B2 cannot be obtained.

  In addition, halogen lamps, helium lamps, metal halide lamps, and the like are known as light sources for film thickness inspection apparatuses, but when illuminating relatively large inspection objects such as parts for large screen displays. As mentioned above, there is a problem that all of them are expensive.

  The film thickness inspection apparatus according to the present invention has a structure shown in FIG. 4 in order to solve such a problem. The film thickness inspection apparatus shown in FIG. 4 is an apparatus having a function of performing a film thickness inspection on the three primary color layers formed on the substrate 10 to be inspected, specifically, a color filter for liquid crystal display, plasma About inspection object board 10 which consists of members for displays, such as a display panel and a substrate for organic EL displays, a red colored layer, a green colored layer, and a blue colored layer formed on the board have uniform film thickness Used to check whether or not. Here, for convenience of explanation, the X axis and the Y axis are defined as shown so that the plane parallel to the main surface of the inspection target substrate 10 is the XY plane.

  The light source 20 is a light source in which a straight tube type three-wavelength fluorescent lamp is accommodated in an elongated casing, and has a function of illuminating a linear visual field region F (a hatched region in the drawing) on the inspection target substrate 10. Fulfill. The line sensor camera 30 is a camera in which a line sensor and an optical system are housed in a housing, and fulfills a function of capturing the linear visual field region F and capturing it as a one-dimensional image. That is, the reflected light of the light emitted from the light source 20 to the inspection target substrate 10 is captured by the line sensor camera 30. Further, the transport device 50 plays a role of transporting the inspection target substrate 10 in the X-axis direction, and the image processing device 60 combines the one-dimensional images sent from the line sensor camera 30 to form the inspection target substrate 10 on the inspection target substrate 10. It plays the role of creating a two-dimensional image showing the film thickness distribution of the colored layer.

  The line sensor in the line sensor camera 30 is configured by arranging a plurality of light receiving elements in a direction parallel to the Y axis, and the linear visual field region F on the inspection target substrate 10 that has been transported by the transport device 50. It is arrange | positioned so that it can image from diagonally upward. Therefore, the linear visual field region F is an elongated region extending in a direction parallel to the Y axis. In the figure, for convenience, the linear visual field region F is shown as a hatched rectangular region. However, in actuality, the width of the linear visual field region F in the X-axis direction is very narrow and substantially linear. Become an area. An image captured at a time by the line sensor camera 30 is a one-dimensional image along the linear visual field region F. While the substrate to be inspected 10 is transported at a constant speed in the X-axis direction by the transport device 50, By repeatedly taking a one-dimensional image by the line sensor camera 30, it is possible to scan the upper surface of the inspection target substrate 10 with the linear visual field region F, and the obtained one-dimensional images are processed by the image processing device 60. By combining in step 2, a two-dimensional image showing the film thickness distribution of the colored layer on the inspection target substrate 10 is created.

  The image processing device 60 can be configured, for example, by incorporating a predetermined image processing program into a personal computer. When the image processing device 60 is configured by a personal computer, a two-dimensional image including an interference fringe pattern can be displayed on the personal computer monitor device. The operator in charge of inspection confirms the presence or absence of film thickness unevenness while monitoring the monitor screen, and takes measures such as issuing a warning when film thickness unevenness is observed.

  On the other hand, although the conveying apparatus 50 is drawn as a simple schematic diagram in FIG. 4, it can be configured by a general apparatus such as a conveyor. When a personal computer is used as the image processing device 60, the transport device 50 can be controlled by a sequencer circuit connected to the personal computer.

  In practice, the image processing apparatus 60 performs preprocessing such as shading correction and noise removal on the captured two-dimensional image, and then enhances the interference fringe pattern (for example, pixels). It is preferable to execute gradation portion enlargement processing for enlarging a gradation portion having a large frequency value on a histogram indicating the frequency of values. Moreover, after performing a binarization process and a labeling process as needed, a particle analysis process (a calculation process of a size and a fillet diameter) can be further performed. Since a specific method for such processing is a known technique, detailed description thereof is omitted here.

  One of the important features of the film thickness inspection apparatus according to the present invention is that a straight tube type three-wavelength fluorescent lamp (hereinafter simply referred to as a three-wavelength tube) is used as the light source 20. The three-wavelength tube is arranged so that at least the linear visual field region F can be illuminated obliquely from above, and the longitudinal direction thereof is parallel to the Y axis. The three-wavelength tube is a straight tube fluorescent lamp (so-called white fluorescent lamp) widely used in general houses and offices, and its cost is extremely low compared to a metal halide lamp.

  The inventor of the present application has found that the emission spectrum of the three-wavelength tube is extremely suitable for the film thickness inspection of the colored layers of the three primary colors of RGB. FIG. 5 is a graph showing an emission spectrum of a commercially available three-wavelength tube and transmission spectra of three kinds of colored layers of blue / green / red used in a general color filter. Although there are some differences depending on the manufacturers and varieties that manufacture the three-wavelength tube, basically, the emission spectrum of the three-wavelength tube has several peaks as shown by the thick solid line in this graph. Have. In addition, when attention is paid to the wavelength ranges of the three major peaks, it can be seen that they overlap each other in the transmission spectrum regions of three kinds of colored layers of blue / green / red. In other words, the light in the wavelength range of the three major peaks can be used as light for inspecting the thickness of the three kinds of colored layers of blue / green / red.

  In the film thickness inspection apparatus shown in FIG. 4, a band pass filter 40 is disposed between the linear visual field region F and the line sensor camera 30. This band pass filter 40 is an optical filter that selectively transmits a predetermined range of light within the transmission spectrum region of the colored layer to be inspected. In short, from the emission spectrum of the three-wavelength tube shown in FIG. It plays the role of selecting light in the wavelength range of any of the three major peaks.

  For example, if an optical filter that selectively transmits light in the range of 430 to 450 nm is used as the bandpass filter 40, the emission spectrum of the light of the three-wavelength tube passing through the bandpass filter 40 is as shown in FIG. It will look like the solid line on the graph. This overlaps the transmission spectrum of the blue colored layer indicated by a broken line in the figure, and it can be seen that the light is suitable for the film thickness inspection for the blue colored layer. Similarly, if an optical filter that selectively transmits light in the range of 535 to 555 nm is used as the bandpass filter 40, the emission spectrum of the light of the three-wavelength tube passing through the bandpass filter 40 is as shown in FIG. This will be as shown by the solid line in the graph. This overlaps with the transmission spectrum of the green colored layer indicated by the alternate long and short dash line in the figure, and it can be seen that the light is suitable for the film thickness inspection for the green colored layer. If an optical filter that selectively transmits light in the range of 600 to 620 nm is used as the bandpass filter 40, the emission spectrum of the light of the three-wavelength tube passing through the bandpass filter 40 is as shown in FIG. The graph will look like a thick solid line. This overlaps the transmission spectrum of the red colored layer indicated by a thin solid line in the figure, and it can be seen that the light is suitable for the film thickness inspection for the red colored layer.

  After all, as the bandpass filter 40 in the film thickness inspection apparatus shown in FIG. 4, three types of bandpass filters that selectively transmit light corresponding to the three primary colors RGB are prepared, and these three types of bandpass filters are prepared. If it is configured so that it can be selectively attached between the linear visual field region F and the line sensor camera 30, the film thickness inspection apparatus can perform the film thickness inspection of the colored layers of the three primary colors of RGB. become able to. Some band-pass filters 40 use absorptive colored glass or gelatin, but in order to obtain an interference fringe pattern having a high contrast, a thin film deposition type filter having a transmission characteristic with a narrow spectral width is used. Is preferred.

  Of course, in practice, the three types of colored layers of blue / green / red are separately inspected one by one. For example, first, the uniformity of the red colored layer is inspected by a two-dimensional image obtained by the inspection using the bandpass filter 40 that transmits the red wavelength region, and then the bandpass filter that transmits the green wavelength region. The uniformity of the green colored layer is inspected by the two-dimensional image obtained by the inspection using 40, and finally the blue color is obtained by the two-dimensional image obtained by the inspection using the bandpass filter 40 that transmits the blue wavelength region. The uniformity of the colored layer may be inspected.

  As shown in the graphs of FIGS. 6 to 8, the light transmitted through each bandpass filter 40 becomes light with a considerably narrow wavelength range. In fact, it can be seen that light comparable to the spectrum width of the low-pressure sodium lamp shown in FIG. 3 can be obtained. Thus, the light obtained by the combination of the three-wavelength tube in the light source 20 and the bandpass filter 40 becomes light suitable for film thickness inspection based on the principle using the interference phenomenon shown in FIG. An interference fringe pattern sufficient for inspection can be obtained on the image captured at 30.

  Thus, in the film thickness inspection apparatus according to the present invention, by using a three-wavelength tube, that is, a straight tube-type three-wavelength fluorescent lamp, as the light source 20, the following merits can be obtained. First, since the cost of the fluorescent lamp itself is extremely low, the cost of the entire apparatus can be reduced. As described above, the straight tube type three-wavelength fluorescent lamp is mass-produced as a so-called white fluorescent lamp, and the cost is extremely low as compared with other light source lamps.

  Second, by using a straight tube lamp (so-called linear light source), a single lamp can cover a wide area. That is, as shown in FIG. 4, the light source 20 is arranged so that the longitudinal direction thereof is parallel to the Y axis, and the light receiving element array direction of the line sensors in the line sensor camera 30 is also parallel to the Y axis. By adopting a configuration in which imaging is performed while the inspection target substrate 10 is transported in the X-axis direction by the transport device 50, sufficient inspection can be performed even on the inspection target substrate 10 having a large area. become. Currently, a three-wavelength tube having a total length of about 2 m is commercially available. If such a three-wavelength tube is used, it is possible to deal with a large inspection target substrate 10 having a width of about 2 m.

  Thirdly, the emission spectrum of the three-wavelength tube has three major peaks as shown in the graph of FIG. 5, and the wavelengths of these peaks are transmission spectra for the three types of colored layers of blue / green / red. In combination with the three types of band-pass filters 40, it is possible to inspect all of the three primary color layers of RGB. This is an indispensable condition for performing a film thickness inspection on a color display member such as a color filter for a liquid crystal display.

  In principle, the band-pass filter 40 can be disposed between the light source 20 and the linear visual field region F. In this case, however, the band-pass filter 40 has a width over the entire length of the light source 20. Since it is necessary to prepare a filter, it is practically preferable to arrange the filter between the linear visual field region F and the line sensor camera 30 as in the embodiment shown in FIG. The line sensor camera 30 includes an optical system such as a lens, and has a function of reducing the linear visual field region F and forming an image on the line sensor. Accordingly, the width of the bandpass filter 40 disposed between the linear visual field region F and the line sensor camera 30 can be set to be considerably smaller than the total length of the linear visual field region F.

  The embodiment shown in FIG. 4 is further devised in some details. Hereinafter, this fine device will be described with reference to the side view of FIG.

  The first contrivance is that a short wavelength band cut filter 21 is attached to the light source 20. This filter 21 is a short wavelength band cutting filter 21 arranged in the light emission direction of the light source 20, and specifically has a function of cutting light in a region having a wavelength of 400 nm or less. As shown in the side view of FIG. 9, the light from the light source 20 (light from the three-wavelength tube) passes through the filter 21 and is irradiated onto the inspection target substrate 10. The state in which the filter 21 is joined to the light source 20 is also shown in the perspective view of FIG. As described above, the filter 21 is provided between the three-wavelength tube and the linear visual field region F because light in a short wavelength region, which is a photosensitive band of the photosensitive material layer formed on the inspection target substrate 10. This is a consideration for preventing the photosensitive material layer on the inspection target substrate 10 from being adversely affected by cutting.

  In general, a photosensitive material is contained in a colored layer such as a color filter. For this reason, in order to perform a film thickness inspection, if light in a short wavelength region (mainly ultraviolet light) is irradiated, the photosensitive material may be exposed to light and deteriorated. By disposing the short wavelength band cut filter 21 to cut the light component in the short wavelength band, it is possible to prevent such an adverse effect. In the example shown in FIG. 9, the light L1 from the light source 20 includes light in the short wavelength region, but the light L2 that has passed through the filter 21 is cut off the light in the short wavelength region. Even if the substrate 10 to be inspected is irradiated, the above-described harmful effects do not occur. As the short-wavelength-cut filter 21, a commercially available ultraviolet cut filter, yellow filter, or the like can be used.

  The second device is the arrangement angle of the bandpass filter 40. In the case of the embodiment shown in FIG. 9, the bandpass filter 40 is arranged so as to be parallel to the inspection target substrate 10 (that is, parallel to the XY plane). As described above, the bandpass filter 40 is arranged in parallel to the inspection target substrate 10 because the reflected light on the surface of the bandpass filter 40 enters the linear visual field region F and the bandpass filter 40 itself is reflected. It is a consideration not to be included. As illustrated, the light L2 irradiated to the linear visual field region F on the surface of the inspection target substrate 10 travels to the line sensor camera 30 as reflected light L3. At this time, the reflected light L3 passes through the band-pass filter 40, but a part of the reflected light L3 is reflected on the surface of the band-pass filter 40 to generate reflected light L5. If the band-pass filter 40 is arranged in parallel with the inspection target substrate 10 as in the illustrated example, this reflected light L5 can be guided in the direction shown in the figure, and reflected in the linear visual field region F. Can be prevented.

  However, the arrangement angle of the bandpass filter 40 is not necessarily set parallel to the inspection target substrate 10. In short, it is sufficient that the reflected light L5 does not go into the linear visual field region F, so that the normal n standing on the main surface is the optical axis of the line sensor (in the case of the figure, the light L3, L4 (Direction) may be arranged so as to be inclined.

  When a thin film deposition type filter is used as the bandpass filter 40, the transmission characteristics change according to the incident angle of light. Therefore, the transmission characteristics are designed in consideration of the arrangement angle of the filter. Is preferred. Further, considering that the transmission characteristics change according to the incident angle of light, the density of interference fringes may be different between the center and the end of the field of view of the line sensor camera 30. In order to avoid this, it is desirable to use a lens having a focal length as long as possible (lens on the telephoto side) as an optical system used for the line sensor camera 30.

  The third device is that the angle θ formed by the optical axis of the line sensor and the main surface of the inspection target substrate 10 is set to 30 ° to 70 °. In the illustrated example, the angle formed by the central axis (the direction of the light L1, L2) of the irradiation light from the light source 20 and the main surface of the inspection target substrate 10 is also the same angle θ so that efficient illumination is possible. The settings are as follows. According to experiments conducted by the inventors of the present application, when the angle θ exceeds 70 °, the reflectance at the surface of the colored film such as a general color filter and the interface with the substrate becomes very small, and interference fringes are obtained. Sufficient reflected light cannot be obtained. On the other hand, when the angle θ is less than 30 °, the reflectance of light on the surface of the colored film increases, so that sufficient interference fringes cannot be obtained.

  In practicing the present invention, it is preferable to use a high frequency lighting power source instead of a normal commercial AC power source for lighting the three-wavelength tube. This is because the frequency component of the commercial AC power source can be prevented from being observed as a noise component by using the high frequency lighting power source.

  Further, the present invention relates to an inspection apparatus that performs a film thickness inspection for three primary color layers using a straight tube type three-wavelength fluorescent lamp. For example, only a film thickness inspection for a blue color layer is performed. If possible, it is sufficient to use a straight-tube blue fluorescent lamp as the light source 20 instead of the straight-tube three-wavelength fluorescent lamp.

  As mentioned above, although this invention was demonstrated based on embodiment shown in figure, of course, this invention is not limited to this embodiment, In addition, it can implement with a various form. In particular, the wavelength values shown in the above-described embodiments are specific examples, and the present invention is not limited to these specific wavelength values. In the above-described embodiment, a three-wavelength fluorescent lamp having an emission spectrum having a peak in a specific wavelength region as shown in FIG. 5 is used. However, the emission spectrum of the light source used is not necessarily as shown in FIG. It is not limited to things. If the emission spectrum of the light source is different, the bandpass filter prepared accordingly may be changed. For example, when a three-wavelength fluorescent lamp having an emission spectrum having a peak in a wavelength range of 480 to 500 nm is used as blue light, the blue bandpass filter is within a range of 480 to 500 nm. An optical filter that selectively transmits light may be used. In this case, as a filter for cutting light in a short wavelength region, for example, a region having a wavelength of 450 nm or less is used instead of the filter for cutting light in a region having a wavelength of 400 nm or less used in the above-described embodiment. A filter capable of cutting up to a higher wavelength range according to the transmission wavelength range of the band-pass filter, such as a filter to be cut, can also be used.

It is a side view of the inspection object substrate for showing the inspection principle of the general film thickness inspection device using light interference. It is a side sectional view ((a)) of the inspection target substrate in which the film thickness unevenness occurs in the colored layer, and a plan view ((b)) of the interference fringe pattern showing the film thickness unevenness. It is a graph which shows the transmission spectrum of a blue colored layer, and the spectrum of a low-pressure sodium lamp. It is a perspective view which shows the structure of the film thickness inspection apparatus which concerns on one Embodiment of this invention. It is a graph which shows the emission spectrum of 3 wavelength tubes generally marketed, and the transmission spectrum of three kinds of colored layers of blue / green / red used in a general color filter. It is a graph which shows the emission spectrum of the light obtained through the "optical filter which selectively permeate | transmits the light within the range of 430-450 nm", and the transmission spectrum of a blue colored layer of the light of 3 wavelength tubes. It is a graph which shows the emission spectrum of the light obtained through the "optical filter which selectively permeate | transmits the light within the range of 535-555 nm", and the transmission spectrum of a green colored layer of the light of 3 wavelength tubes. It is a graph which shows the emission spectrum of the light obtained through the "optical filter which selectively permeate | transmits the light within the range of 600-620 nm", and the transmission spectrum of a red colored layer of the light of 3 wavelength tubes. It is a side view which shows the optical arrangement | positioning of the film thickness inspection apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inspection object board | substrate 11 ... Colored layer 20 ... Light source (straight tube type 3 wavelength type fluorescent lamp)
21 ... Short wavelength band cutting filter 30 ... Line sensor camera 40 ... Band pass filter 50 ... Conveying device 60 ... Image processing device (personal computer)
A ... Illuminating light B1 ... Reflected light B2 on the upper surface of the colored layer 11 ... Reflected light F on the lower surface of the colored layer 11 ... Linear visual field regions L1-L5 ... Light path n ... Normal line θ ... Angle

Claims (5)

An apparatus for inspecting the uniformity of the film thickness for the colored layers of the three primary colors RGB using the interference of light ,
A transport device that transports an inspection target substrate having a colored layer in the X-axis direction so that its main surface is parallel to the XY plane when an XY two-dimensional coordinate system is defined;
It is configured by arranging a plurality of light receiving elements in a direction parallel to the Y axis, and is arranged so that a linear visual field region on the inspection target substrate transported by the transport device can be imaged obliquely from above. A line sensor;
A straight tube type three-wavelength fluorescent lamp arranged so that the longitudinal direction thereof is parallel to the Y axis so that at least the linear visual field region can be illuminated obliquely from above;
A bandpass filter that is disposed between the linear visual field region and the line sensor and selectively transmits a predetermined range of light within a transmission spectrum region of a colored layer to be inspected;
By synthesizing a plurality of one-dimensional images picked up by the line sensor, the film thickness distribution of the colored layer on the inspection target substrate is determined as an interference fringe pattern of reflected light from the upper surface and reflected light from the lower surface of the colored layer. An image processing apparatus for creating a two-dimensional image shown as
With
The spectrum of the three-wavelength fluorescent lamp has three peaks that overlap the transmission spectrum region of each colored layer of the three primary colors RGB,
A film thickness inspection apparatus for three primary color layers, wherein three types of band-pass filters that selectively transmit light in a wavelength region corresponding to the three peaks are prepared as the band-pass filters. In the film thickness inspection apparatus according to claim 1,
An optical filter that selectively transmits light in the range of 430 to 450 nm, an optical filter that selectively transmits light in the range of 535 to 555 nm, and an optical filter that selectively transmits light in the range of 600 to 620 nm A film thickness inspection apparatus for three primary color layers, wherein the three types of band-pass filters can be selectively attached between the linear visual field region and the line sensor. In the film thickness inspection apparatus according to claim 1 or 2,
A filter is provided between the three-wavelength fluorescent lamp and the linear visual field region to cut light in a short wavelength region, which is a photosensitive band of the photosensitive material layer formed on the inspection target substrate. A film thickness inspection apparatus for the three primary color layers. In the film thickness inspection apparatus according to any one of claims 1 to 3,
The bandpass filter is arranged so that the normal line standing on its main surface is inclined with respect to the optical axis of the line sensor, so that the reflected light on the surface of the bandpass filter does not enter the linear visual field region. Film thickness inspection device for the three primary color layers. In the film thickness inspection apparatus according to any one of claims 1 to 4,
A film thickness inspection apparatus for three primary color layers, wherein an angle formed by an optical axis of a line sensor and a main surface of a substrate to be inspected is set to 30 ° to 70 °.