KR20100058012A - Optical system for detecting defect - Google Patents

Abstract

PURPOSE: An optical system for inspecting defects is provided to perform an inspection using a ray capable of penetrating a wafer for a semiconductor device and a glass for a flat panel display. CONSTITUTION: An optical system for inspecting defects comprises a first light source(110a), first IR filters(120a,120b), a reflective light camera(160a), a second light source(110b), and a transmission light camera(160b). The first IR filters filter a ray of an infrared range from the rays radiated from the first light source. The reflective light camera receives the rays penetrated through the first IF filters. The second light source radiates the rays of the infrared range. The transmission light camera is radiated from the second light source. The transmission light camera receives the rays of the infrared range passing through a checking object.

Description

OPTICAL SYSTEM FOR DETECTING DEFECT}

The present invention relates to an optical system for defect inspection, and more particularly, a flat panel display (FPD) by simultaneously performing defect inspection using reflected light and defect inspection using transmitted light using light having different wavelengths. The present invention relates to an optical system that can shorten the time required for defect inspection during a manufacturing process of a display or a semiconductor device.

Thin film transistors (TFTs) are commonly used in the manufacture of flat panel displays (FPDs), such as liquid crystal displays (LCDs), which are widely used in TVs or computer monitors.

The manufacturing of such a thin film transistor is based on a conventional semiconductor wafer manufacturing process, but the key is to uniformly manufacture each cell for a large area. Therefore, immediately after each unit process is completed, the defects must be identified for each unit process, and the cause thereof must be analyzed to determine the progress or rework to the next process to manage the yield.

In general, the basic manufacturing process of the thin film transistor is a process of depositing a metal and an organic film material on a glass substrate or the like, and patterning the thin film transistor. Can be determined.

One of the conventionally used methods was to identify defects by irradiating light onto a thin film transistor being manufactured and analyzing a reflected image. That is, when light is irradiated to the thin film transistor, the reflected light of the normal portion shows white color, but since black spots appear at a defective point where a short circuit or the like occurs, the defect can be detected by detecting such black spots.

However, such a method by the reflected light alone was insufficient to grasp the defect and find out the cause thereof. Specifically, the black spot in the image obtained using the reflected light by the thin film transistor may be due to a genuine defect such as a short circuit in the corresponding cell, but may be due to a simple foreign matter or discoloration, and thus, the part that appears as a black spot in the image. It was difficult to determine whether or not this was a genuine defect.

What has emerged to complement this point is a method of using both reflected and transmitted light. In other words, the light is transmitted through the thin film transistor, and the image of the transmitted light is imaged to obtain an image. By comparing the image obtained by the reflected light with the image obtained by the transmitted light in this way, it is possible to more accurately grasp the defect and to easily find out the cause thereof.

However, conventionally, a process of obtaining an image by reflected light and a process of obtaining an image by transmitted light are performed separately. That is, the reflected light is irradiated to the thin film transistor to collect the reflected light to image the image, and then the transmissive light is irradiated to the thin film transistor to collect the transmitted light to image the image.

According to this method, since the process of acquiring the image by the reflected light and the process of acquiring the image by the transmitted light must be performed separately, accurate defect confirmation may be possible, but there is a problem that the time required for the defect confirmation is doubled.

Therefore, there is a need for development of a technology that can accurately identify defects during the manufacturing process of a thin film transistor and the like and can shorten the time required for defect identification.

The present invention is to solve the above-mentioned problems of the prior art, in the defect inspection performed during the manufacturing process of the thin film transistor, the defect inspection through the reflected light and the defect inspection through the transmitted light using two lights having different wavelengths By doing this, it is possible to perform both inspections at the same time to shorten the time required for defect inspection.

In addition, another object of the present invention is to provide a defect inspection optical system that can be applied to various fields by performing defect inspection using light that can transmit not only glass for flat panel display but also wafer for semiconductor element.

According to an embodiment of the present invention for achieving the above object, as an optical system for identifying a defect of the inspection object, a first light source, a first for filtering out the infrared band of the light emitted from the first light source After passing through an infrared cut filter, the first infrared cut filter, a reflection light acquisition camera for receiving the light reflected by the inspection object, a second light source for emitting the light of the infrared band, and is emitted from the second light source There is provided an optical system comprising a camera for obtaining the transmitted light for receiving the light of the infrared band passing through the inspection object.

The optical system may further include a first beam splitter configured to reflect at least a portion of the light passing through the first infrared cut filter toward the inspection target.

At least a portion of the infrared band light emitted from the second light source and passing through the inspection object may be reflected by the first beam splitter, and the optical system may include an infrared band reflected by the first beam splitter. The apparatus may further include a second beam splitter configured to reflect at least some of the light toward the transmitted light obtaining camera.

The first beam splitter or the second beam splitter may be a half mirror.

The optical system may further include a second infrared cut filter disposed on the front surface of the camera for obtaining the reflected light, and blocking the light of the infrared band incident to the camera for obtaining the reflected light.

The optical system may further include an infrared pass filter disposed in front of the transmitted light acquisition camera, such that only light in an infrared band may be received by the transmitted light acquisition camera.

The optical system may further include a correcting lens disposed at a front surface of the transmitted light obtaining camera and correcting light to be received by the transmitted light obtaining camera.

The optical system may further include an objective lens disposed in front of the inspection object and configured to enlarge at least one of light incident to the inspection object, light reflected by the inspection object, and light passing through the inspection object. It may include.

The reflected light obtaining camera or the transmitted light obtaining camera may be a charge-coupled device (CCD).

The test object may be a flat panel display (FPD) or a semiconductor device.

According to the present invention, in the defect inspection performed during the manufacturing process of the thin film transistor, by performing the defect inspection through the reflected light and the defect inspection through the transmitted light using two lights having different wavelengths, both inspection can be performed at the same time The time required for the defect inspection can be shortened accordingly.

In addition, the defect inspection optical system of the present invention can be applied to various fields because the defect inspection is performed using light that can transmit not only the glass for flat panel display but also the wafer for semiconductor element.

DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. Like reference numerals in the drawings refer to the same or similar functions throughout the several aspects.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

Configuration of the device

1 is a view showing the overall configuration of an optical system for defect inspection according to an embodiment of the present invention.

As shown in FIG. 1, the optical system of the present invention includes a first light source 110a and a second light source 110b. The first light source 110a provides the light for inspecting the defect through the reflected light by the inspection object 100, and the second light source 110b inspects the defect using the light passing through the inspection object 100. To provide light.

In addition, light from the first light source 110a from which the infrared light is removed by the first infrared cut filter 120a and the first infrared cut filter 120a to block infrared rays from the light provided from the first light source 110a. A first beam splitter (130a) for reflecting at least a portion of the beam to the inspection object 100, a reflection light obtaining camera 160a for obtaining the light reflected by the inspection object 100, and a reflection light acquisition It may include a second infrared cut filter 120b disposed on the front of the camera (160a).

On the other hand, the second beam splitter 130b for reflecting at least a portion of the light emitted from the second light source 110b and transmitted to the inspection object 100 and directed to the camera 160b for obtaining the transmitted light, and for obtaining the transmitted light The correction lens 150 and the infrared ray pass filter 120c disposed in front of the camera 160b may be included. In addition, the front surface of the inspection object 100 may be provided with an objective lens 140 to enlarge the incident light.

The optical system of the present invention performs defect inspection on the inspection object 100 by using visible light reflected by the inspection object 100 and infrared rays passing through the inspection object 100. In this way, since visible and infrared rays having different wavelengths are used, the inspection using reflected light and the inspection using transmitted light can be performed simultaneously using the filters 120a, 120b, and 120c that select only light having a wavelength necessary for inspection. do. In addition, since infrared rays can also penetrate a substrate such as a wafer, not only a flat panel display (FPD) including a thin film transistor (TFT) using a glass substrate, but also a semiconductor device using a wafer substrate. The optical system of the present invention can also be used for inspection of defects.

First, the first infrared cut filter 120a filters out infrared rays from the light emitted from the first light source 110a and passes only the visible light band. In this way, the light from the first light source 110a from which the infrared light is removed by the first infrared cut filter 120a, that is, the light in the visible light band, is used for defect inspection through the reflected light.

In addition, the second infrared cut filter 120b is disposed on the front surface of the reflected light obtaining camera 160a to prevent the infrared rays from entering the reflected light obtaining camera 160a. Since the infrared light emitted from the second light source 110b is used for the defect inspection using the transmitted light, it should not be incident on the reflected light acquiring camera 160a. Infrared light emitted from the second light source 110b passes through the inspection object 100 and the objective lens 140 and is reflected by the first beam splitter 130a, and part of the infrared light is transmitted as it is. 160a). The second infrared cut filter 120b blocks the infrared rays toward the reflected light obtaining camera 160a so that the reflected light obtaining camera 160a receives only the visible light used for the defect inspection through the reflected light.

On the other hand, the infrared filter 120c is disposed in front of the transmission light acquisition camera 160b, so that only the infrared ray is incident on the transmission light acquisition camera 160b. Some of the light in the visible light band emitted from the first light source 110a passes through the second beam splitter 130b as it is, but part of the light is reflected by the second beam splitter 130b to the inspection object 100. After the light is reflected by the inspection object 100, the light may travel toward the camera 160b for obtaining the transmitted light. In addition, a portion of the light reflected by the inspection object 100, that is, the light in the visible light band used for the defect inspection using the reflected light, may be routed by the first beam splitter 130a and the second beam splitter 130b. It is also possible to accumulate by 90 ° and proceed toward the transmitted light obtaining camera 160b. The infrared filter 120c filters out the visible light bands that proceed to the transmitted light acquisition camera 160b so that only infrared light may be incident on the transmitted light acquisition camera 160b.

The first and second beam splitters 130a and 130b divide light into two or more pieces. That is, some of the light incident on the first and second beam splitters 130a and 130b are transmitted as they are, maintaining the original traveling direction, and the other part is reflected to change the traveling path by 90 °. The first and second beam splitters 130a and 130b may be implemented as half mirrors having a reflectance of 40 to 60%.

Next, the correcting lens 150 is disposed in front of the transmitted light acquisition camera 160b and performs a function of correcting the light width, the sharpness of the focus, and the uniformity of light incident on the transmitted light acquisition camera 160b. The correction lens 150 may be implemented by a known condensing lens.

The reflected light obtaining camera 160a and the transmitted light obtaining camera 160b perform a function of detecting visible light and infrared light, respectively. These may each be an imaging device such as a charge-coupled device (CCD) or a micro microscope. In addition, a processor unit (not shown) for converting an optical signal detected by the reflected light acquisition camera 160a and the transmitted light acquisition camera 160b into a predetermined electrical signal may be further included. The processor unit may convert the intensity of the input light into a magnitude of a voltage or a current and output the converted light.

The first light source 110a emits a beam including light in the visible light band. As described above, the light emitted from the first light source 110a passes through the first infrared cut filter 120a so that only light in the visible light band remains, and the light in the visible light band is used for defect inspection using reflected light. do. On the other hand, the second light source 110b emits only light in the infrared band, and the light is used for defect inspection using transmitted light. To this end, a predetermined filter may be included in the second light source 110b to emit only light in the infrared band.

Hereinafter, the principle of the defect inspection according to the present invention along with the traveling path of the light emitted from the first light source 110a and the second light source 110b will be described.

Light emitted from the first light source

FIG. 2 is a diagram illustrating a traveling path of light emitted from the first light source 110a in the optical system according to the exemplary embodiment. For the sake of clarity, the reference numerals are the same as in FIG.

Light emitted from the first light source 110a firstly passes through the first infrared cut filter 120a. In this process, infrared light is filtered out and only visible light remains. The light in the visible light band passing through the first infrared cut filter 120a passes through the second beam splitter 130b. In this process, a portion of the visible light is converted to a path of 90 degrees, that is, the reflection is performed. The other part passes through the second beam splitter 130b as it is.

Visible light reflected by the second beam splitter 130b and directed toward the inspection target 100 may be reflected by the inspection target 100 and travel toward the transmitted light acquiring camera 160b. As described above, an infrared light passing filter 120c blocks the visible light to prevent the visible light from entering the transmitted light obtaining camera 160b.

Some of the light transmitted through the second beam splitter 130b as it is is reflected by the first beam splitter 130a again to switch the path of 90 degrees. Thereafter, the target lens 140 proceeds to the inspection object 100, and the light is reflected by the inspection object 100.

After being reflected by the inspection object 100, some of the light passing through the objective lens 140 passes through the first beam splitter 130a as it is, and the other part is reflected by the first beam splitter 130a. May proceed toward the second beam splitter 130b. Some of the light traveling toward the second beam splitter 130b may be reflected toward the transmitted light acquiring camera 160b. As described above, the infrared light pass filter 120c blocks the light to transmit the transmitted light acquiring camera 160b. ) To prevent visible light from entering.

On the other hand, the reflected light transmitted through the first beam splitter 130a as it is is incident to the camera 160a for obtaining the reflected light through the second infrared cut filter 120b.

In this manner, the reflected light in the visible light band may be input to the reflected light acquiring camera 160a.

Light emitted from the second light source

3 is a view showing a path of the light emitted from the second light source 110b in the optical system according to the exemplary embodiment of the present invention. For the sake of clarity, the reference numerals are the same as in FIG.

The second light source 110b may be disposed on the rear surface of the test object 100. That is, the transmission light obtaining camera 160b and the second light source 110b may be disposed at opposite sides with respect to the inspection object 110. This is because the transmitted light obtaining camera 160b needs to receive light from the second light source 110b that has passed through the inspection object 100.

The light emitted from the second light source 110b, that is, the light of the infrared band passes through the inspection object 100 and passes through the objective lens 140 to reach the first beam splitter 130a. Some of the light in the infrared band that reaches the first beam splitter 130a is reflected and travels toward the second beam splitter 130b, and the other part passes through the first beam splitter 130a as it is and acquires the reflected light camera ( 160a). As described above, the second infrared cut filter 120b blocks the light to prevent the light of the infrared band from entering the reflected light acquiring camera 160a.

On the other hand, some of the infrared band of light propagated toward the second beam splitter 130a is directed toward the transmitted light obtaining camera 160b. This light passes through the infrared ray passing filter 120c, and various corrections are performed by the correction lens 150, and then is input to the transmitted light obtaining camera 160b.

The optical system of the present invention performs a defect inspection using reflected light and a defect inspection using transmitted light using visible light and infrared rays, and prevents mutual interference between visible light and infrared rays by using filters 120a, 120b, and 120c, thereby reflecting the reflected light. The defect inspection using and the defect inspection using the transmitted light can be performed at the same time. Accordingly, the time used for the defect inspection can be shortened.

In addition, since the optical system of the present invention uses infrared rays, not only a flat panel display using a glass substrate but also a wafer substrate can be transmitted, so that the optical system can be used for defect inspection of a semiconductor element using a wafer substrate.

In the present invention as described above has been described by the specific embodiments, such as specific components and limited embodiments and drawings, but this is provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations are possible from these descriptions.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the claims described below, belong to the scope of the present invention. something to do.

1 is a view showing the overall configuration of an optical system for defect inspection according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a traveling path of light emitted from a first light source of an optical system according to an exemplary embodiment of the present disclosure.

3 is a view showing a path of the light emitted from the second light source of the optical system according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: inspection target

110a, 110b: light source

120a, 120b: infrared cut filter

120c: infrared pass filter

130a, 130b: beam splitter

140: objective lens

150: correction lens

160a: camera for acquiring reflected light

160b: transmission light acquisition camera

Claims (10)

As an optical system for checking the defect of the inspection object, First light source, A first infrared cut filter for filtering out an infrared band of light emitted from the first light source; Reflected light acquisition camera for receiving the light reflected by the inspection object after passing through the first infrared cut filter, A second light source for emitting light in the infrared band, and Transmitted light acquisition camera for receiving the light of the infrared band emitted from the second light source and passed through the inspection object Optical system comprising a. The method of claim 1, And a first beam splitter for reflecting at least a portion of the light passing through the first infrared cut filter toward the inspection object. The method of claim 2, At least a portion of the infrared band light emitted from the second light source and passing through the inspection object is reflected by the first beam splitter, And a second beam splitter for reflecting at least some of the light in the infrared band reflected by the first beam splitter to be directed to the transmitted light acquisition camera. The method according to claim 2 or 3, The first beam splitter or the second beam splitter is a half mirror. The method of claim 1, And a second infrared cut filter disposed on a front surface of the reflected light obtaining camera and blocking the light of the infrared band incident to the reflected light obtaining camera. The method of claim 1, And an infrared pass filter disposed in front of the camera for acquiring transmitted light, such that only infrared light can be received by the camera for acquiring transmitted light. The method of claim 1, And a correction lens disposed in front of the camera for acquiring the transmitted light and correcting light to be received by the camera for acquiring the transmitted light. The method of claim 1, And an objective lens disposed on a front surface of the inspection object and configured to enlarge at least one of light incident to the inspection object, light reflected by the inspection object, and light passing through the inspection object. Optical system. The method of claim 1, The reflected light acquisition camera or transmitted light acquisition camera is a CCD (Charge-Coupled Device) characterized in that the optical system. The method of claim 1, The inspection object is an optical system, characterized in that the flat panel display (FPD) or a semiconductor device.

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