JP2850031B2 - Inspection method and inspection device for pattern members - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a technique for inspecting a pattern member having a plurality of patterns of different colors on a flat surface of a substrate, and particularly to a technique for inspecting a color member for a color liquid crystal display device. The present invention relates to a technique effective for inspecting a protruding defect due to foreign matter on a filter surface.

(Prior Art) Inspection of a surface having a pattern on a transparent glass substrate, such as a photomask or a reticle, and inspection of foreign matter on a surface of a wafer for manufacturing a semiconductor device are generally performed using foreign matter. A method of detecting reflected scattered light is employed. In that method, a surface of a substrate to be inspected is irradiated with laser light, and scattered light is detected at a position where light reflected directly from the substrate is not received. Foreign matter such as dust emits relatively large scattered light, and the presence of the foreign matter can be detected based on the scattered light. For example,
JP-A-63-33648 shows one such foreign matter inspection apparatus.

In addition, as a technology that further develops a technology for inspecting foreign substances using scattered light, a technology that utilizes the polarization characteristics of light has been developed. The principle of the device utilizing this polarization characteristic is as follows. That is, a polarized light beam (for example, an S-polarized laser beam having a vibration plane parallel to an irradiation surface or a P-polarized laser beam having a vibration plane perpendicular to the irradiation surface) is irradiated on the surface of a wafer or the like to be inspected. In this case, the polarization of the reflected light from the pattern does not change, whereas the reflected light from the foreign substance includes other polarized components.
Then, when the reflected light is received through the analyzer, only the foreign matter can be optically revealed. For example,
Japanese Patent Application Laid-Open No. 61-169750 discloses one of inspection techniques using polarization characteristics.

(Problems to be Solved by the Invention) The present inventors utilize such a foreign substance inspection technology of detecting scattered light to apply red, green, blue, etc. to a flat surface of a base such as a color filter. Investigation was made on inspecting a pattern member having a plurality of patterns of different colors for defects.

Looking at the color filter, the color filter 10 itself is, as shown in FIG.
Red, green and blue pixel patterns 1 on 12 flat surfaces 12a
4R, 14G, and 14B, and a light-shielding pattern 16 located at a boundary between the pixel patterns of each color. In addition, a transparent top coat layer may be formed thereon. The light-shielding pattern 16 is usually made of a metal material such as chromium, and has a very small thickness of about 0.1 μm. On the other hand, each color pixel pattern 14R, 14G, 14B is made of a colored resin material based on, for example, polyimide or the like, and has a thickness of 1 to 2 μm.
m. The light-shielding pattern 16 has a lattice shape, and the inside of the lattice is filled with the pixel patterns 14R, 14G, and 14B of the respective colors. Therefore, the color pixel patterns 14R, 14G, and 14B have the same shape as each other, and have a shape based on a square or a rectangle. And the size of the color pixel pattern is
One side is about 100 to 300 μm. The light-shielding pattern 16
Is several μm to several tens μm, which is a small value compared to the size of a color pixel.

In contrast to such a color filter 10, foreign matter 20 is buried in each color pixel pattern 14R, 14G, 14B,
In many cases, a colored resin material or a top coat layer covers foreign matter on the light shielding pattern 16. In the figure, the foreign matter 20 is buried in the blue color pixel pattern 14B, and the portion is a projection 22. The foreign matter 20 has a size of several tens μm to several hundred μm. The protrusion 22 serving as a defect protrudes above the color pixel pattern and has a height of several μm or more.

Such protrusion-like defects reduce the cell gap of the color liquid crystal display device and cause unevenness in the display screen. Further, when the height of the projection 22 is further increased, a situation may occur in which an electrode formed thereon is short-circuited with an opposing signal electrode.

There is a need for inspection, but the above-mentioned conventional technology has the following problems.

First, in a general inspection technique that does not use polarized light, there is scattering from a step portion of a pattern, so that the S / N ratio between noise and protrusion-like defects is poor, and effective inspection is difficult.

On the other hand, the inspection technique using polarized light can remove the scattered light from the step and increase the S / N ratio. However, even with this technique, it is difficult to reliably detect all the defects because the color filter has a plurality of patterns of different colors. To make this a little clearer. Normally, as a light source for inspection, a monochromatic laser such as He-Ne is used.
Since the colored resin covers the fine foreign matter 20, the intensity of the reflected light is very low depending on the color, and it is difficult to detect the defect as a defect. FIG. 3 shows an experimental example of the reflection intensity, in which white light such as a halogen lamp is used as a light source. From this figure, for example, the wavelength is 632.8 nm
When the He-Ne laser is used, the intensity of the reflected light from the blue portion and the green portion is extremely low, and it can be seen that it is difficult to detect a defect.

(Disclosure of the Invention) An object of the present invention is to provide a technique capable of effectively performing a foreign substance inspection even when a plurality of patterns have different colors.

In the present invention, the surface of the pattern member to be inspected is irradiated with a light beam from a light source containing each light component of red, green, and blue,
The detection light reflected and detected from the pattern member is separated into at least two colors of red, green, and blue, the signal values of the detection light corresponding to the separated light components are compared, and the maximum signal value is selected. The selected signal value is compared with a reference value of a normal pattern of the corresponding color to determine the presence or absence of a defect.

As a light source, each light component as described above is included, and
A beam having a small irradiation diameter and capable of obtaining a parallel beam having a large irradiation intensity is used. It is a so-called white light source, and among them, a white laser is most suitable. The white laser is a negative glow discharge type hollow cathode type He-Cd light three primary color laser. The three primary colors of red, green, and blue light oscillate simultaneously from a single laser tube, and it looks white by the eyes. . Further, this white laser has a single oscillation wavelength of each of the red, green and blue light components, so that color separation is also easy.

For example, a light beam of an S-polarized white laser is irradiated on an inspection object such as a color filter, and the P-polarized component of the scattered light is divided into three components of red, green, and blue, and an output signal detected there is output. Assuming that the values are R, G, and B, the magnitude of each output signal value corresponding to each pattern is as shown in the following table.

Therefore, if the three output signal values are compared and the largest one is selected, the color of the pattern under inspection can be known from the magnitude relationship. Then, by comparing the reference value of the normal pattern of the color with the maximum output signal value, the presence or absence of a defect can be known. As described above, according to the present invention, since the defect is always detected by using the maximum output signal value, a highly reliable inspection can be performed with high detection capability.

(Embodiment) FIG. 1 is an overall configuration diagram showing an embodiment of an inspection apparatus according to the present invention. Hereinafter, referring to this figure,
The contents of the present invention will be clarified.

The pattern member to be inspected is the color filter described above.
It is 10. The color filter 10 is placed on the moving table 30 with the side on which the pattern is formed facing up. The moving table 30 includes a table portion 31 that supports the color filter 10.
And an XY moving mechanism 32 for moving the table portion 31 in the X and / or Y directions. The surface of the color filter 10 on the moving table 30 is irradiated with an S-polarized white laser beam 33 from obliquely above. The irradiation angle θ is
0 ≦ θ <90 °, and is usually set to about 15 °. Also,
The diameter of the laser beam 33 is smaller than the diameter of the pattern of the color filter 10, and is, for example, about several tens (about 20 to 50) μm. In this regard, in order to separate the detection light into colors, it is preferable that the irradiation beam does not straddle between adjacent pixel patterns of different colors. The irradiation means for irradiating the laser beam 33 includes a white laser as a light source, a polarizer for S-polarization, a polygon mirror for scanning, a condenser lens, and the like, although not shown. Scanning by the laser beam 33 is performed in a direction perpendicular to the moving direction of the moving table 30.

When the pattern 22 of the color filter 10 has the protruding defect 22 due to the foreign matter 20 described above, the scattered light 34 of the laser beam 33 reflected from the surface also includes the P-polarized light. Such scattered light 34 is received and detected from a direction perpendicular to the surface of the color filter 10. The detection light that has passed through the condenser lens 35 and the analyzer 36 as light receiving means reaches the color separating means 40 through the mirror 37 and the infrared ray removing filter 38. Color separation means 40
Is to separate the detection light into three colors of blue, green and red.
Here, it is constituted by three dichroic mirrors 41, 42 and 43 exhibiting selective reflection characteristics according to wavelength. Before the detection light enters the color separation means 40, the infrared light removal filter
The infrared light is removed by 38, and the color separation means
The color is separated into three colors of blue, green and red by 40. Since the white lens, which is the light source, oscillates light of a single wavelength corresponding to each of the blue, green, and red light components, the color separation means 40 does not need such a strict color separation function.

The first dichroic mirror 41 is a blue reflecting mirror, the second
The dichroic mirror 42 is a green reflecting mirror and the third dichroic mirror 43 is a red reflecting mirror, and the color-separated detection light enters the detectors 51, 52, and 53, respectively. Each of the detectors 51, 52, and 53 is an optical-electrical converter, which converts an input optical signal into an electric signal and outputs the electric signal to the next-stage amplifiers 61, 62, and 63. Each signal amplified at a fixed rate in each of the amplifiers 61, 62, 63 is output to the selection circuit 70. The selection circuit 70 includes a comparison circuit section 71 and a selection circuit section 72. In the comparison circuit section 71,
The signal values corresponding to the three colors of blue, green, and red are compared, the maximum signal value is selected, and the maximum signal value is output to the selection circuit unit 72 and the reference value generation circuit 80. The selection circuit unit 72 receives the control signal from the comparison circuit unit 71 and outputs only the signal corresponding to the maximum signal value among the three colors to the comparison determination circuit 90 as a detection signal.
On the other hand, the reference value generation circuit 80 generates a reference value of a normal pattern of a color corresponding to the maximum signal value according to the control signal from the comparison circuit unit 71, and outputs the reference value to the other input of the comparison determination circuit 90. And The comparison determination circuit 90 compares the two input signals, and determines that a defect exists only when the detection signal is larger than a reference value.

As described above, in the illustrated inspection apparatus, the detection light is color-separated into three colors, and the presence or absence of a defect is determined using the largest of the color-separated detection signals. Also, it is possible to easily and reliably detect a defect, particularly a protruding defect.

The present invention can be widely applied to inspection of a pattern member having two or more different patterns, in addition to inspection of a pattern of the color filter 10. Needless to say, the pattern includes not only a pattern having a predetermined shape but also a pattern formed solid on one flat surface of the base.

In addition, the present invention can be applied not only to an inspection technique using polarization characteristics but also to a general inspection technique of a method of detecting scattered light.

(Effect of the Invention) According to the present invention, the detection light is color-separated, the color is separated, and the presence / absence of a defect is determined using the maximum detection signal. Even in the case of a pattern member, it is possible to reliably detect a defect, particularly a protruding defect.

Further, in the present invention, a single light source including light components of three primary colors of light is used, and the detection light is subjected to color separation, so that the optical system for irradiation has a relatively simple configuration. be able to.

[Brief description of the drawings]

FIG. 1 is a view showing an example of an inspection apparatus according to the present invention, FIG. 2 is a cross-sectional view of a color filter which is an example of a pattern member to be inspected, and FIG. FIG. 10 color filter (pattern member), 30 moving table, 31 table part, 32 XY moving mechanism,
33 laser beam, 34 scattered light, 40 color separation means, 41, 42, 43 dichroic mirror, 51, 52, 53
Detector (optical-electrical converter), 70... Selection circuit, 80... Reference value generating circuit, 90.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/88

Claims (7)

(57) [Claims] 1. A method for inspecting a pattern member having a plurality of patterns of different colors on one flat surface of a substrate, wherein the flat surface of the substrate is irradiated with a light beam, and scattered light from the substrate side is provided. In the inspection method of the pattern member to detect the defect of the pattern member by detecting the
A light beam from a light source containing red, green, and blue light components is irradiated onto the surface of the pattern member to be inspected, and the detection light reflected from the pattern member and detected is separated into at least two colors of red, green, and blue. Then, the signal values of the detected light corresponding to the decomposed light components are compared, the maximum signal value is selected, and the selected signal value is compared with the reference value of the normal pattern of the corresponding color to determine the defect. A method for inspecting a pattern member, comprising determining whether or not the pattern member exists. 2. The method according to claim 1, wherein the irradiating light beam is polarized light.
The method for inspecting a pattern member according to claim 1. 3. The method according to claim 1, wherein the light source is a white laser. 4. The method according to claim 1, wherein the pattern is made of a colored resin material. 5. A color filter for a color liquid crystal display device having a repeating pattern of red, green and blue.
An inspection method for a pattern member according to claim 1. 6. An inspection apparatus for performing the method for inspecting a pattern member according to claim 1, wherein the inspection apparatus includes the following elements. (A) a table portion on which a pattern member to be inspected is placed, and a moving table including an XY moving mechanism for moving the table portion in the X and / or Y directions; and (b) S-polarized light on the table portion of the moving table. Irradiating means for irradiating the reflected light beam, (c) light-receiving means for receiving reflected light from the pattern member on the moving table, the reflected light including a P-polarized component through an analyzer, and (d) light-receiving means for receiving the reflected light. A color separation unit that separates the detection light into at least two colors of red, green, and blue; (e) a light-to-electric converter that converts each color-separated detection light into an electric signal; and (f) a light-to-electric converter. A selection circuit that compares the converted signal values and selects a maximum signal value; (g) a reference value that receives an output from the selection circuit and generates a reference value of a normal pattern of a color corresponding to the selected signal value Generating circuit, (H) comparing the output signal corresponding to the maximum signal value output from the selection circuit with the output signal corresponding to the reference value output from the reference value generation circuit to determine whether or not the defect is caused by a foreign substance; Comparison judgment circuit. 7. The pattern member inspection apparatus according to claim 6, wherein the color separation means is constituted by a dichroic mirror.