KR20210018402A - Inspection system for depositing one or more layers on a substrate supported by a carrier using holographic reconstruction - Google Patents

Abstract

The present invention provides an in-line deposition inspection system which accurately inspects whether a substrate is abnormal. According to one embodiment of the present invention, the in-line deposition inspection system comprises: a carrier which fixes a substrate thereon and is formed to be moved with the fixed substrate; a first transport part to move the carrier on which the substrate is fixed in a first direction; a first transport chamber to arrange the first transport part therein; one or more deposition parts to deposit a material on the substrate moving by the first transport part; an inspection unit which is arranged on a moving path of the substrate moving by the first transport part to inspect the substrate, and reconstructs three-dimensional information of the surface of the substrate to inspect whether the substrate is abnormal; a light source part to discharge a single-wavelength light to provide the single-wavelength light for the inspection unit; and optical fiber to transfer the single-wavelength light discharged by the light source part to the inspection unit.

Description

In-line deposition inspection system using holographic restoration {INSPECTION SYSTEM FOR DEPOSITING ONE OR MORE LAYERS ON A SUBSTRATE SUPPORTED BY A CARRIER USING HOLOGRAPHIC RECONSTRUCTION}

The present invention relates to an in-line deposition inspection system for inspecting the presence or absence of an abnormality in a deposited substrate by using holographic restoration. More specifically, the present invention is a three-dimensional object to be measured from an image including intensity information of an object hologram generated by interference between a reference light reflected from an optical mirror and an object light reflected from or transmitted through the object to be measured. The present invention relates to a system for inspecting the presence or absence of an abnormality in a substrate by using a method of generating shape information.

A digital holographic microscope refers to a microscope that acquires the shape of an object using digital holography technology.

If a general microscope is a device that acquires the shape of an object by acquiring the reflected light reflected from the object, the digital holographic microscope is a device that acquires the interference and/or diffracted light generated by the object, and obtains the shape of the object from it. to be.

A digital holographic microscope uses a laser that generates light of a single wavelength as a light source, and divides the light generated by the laser into two pieces of light using an optical splitter. At this time, one light (hereinafter referred to as reference light) is directed toward the image sensor, and the other light (hereinafter referred to as object light) is reflected from the target object and directed toward the above-described image sensor so that interference between the reference light and the object light occurs. do.

The image sensor may record the interference fringe according to the interference phenomenon as a digital image, and restore the three-dimensional shape of the object to be measured from the recorded interference fringe. At this time, the interference pattern recorded by the image sensor is usually referred to as a hologram.

Conventional optical holographic microscopes record the interference pattern according to the interference phenomenon between reference light and object light with a special film. At this time, when the reference light is irradiated on the special film on which the interference pattern is recorded, the shape of the virtual object to be measured is restored at the place where the object to be measured was located.

Compared with conventional optical holographic microscopes, digital holographic microscopes digitize (or digitize) the interference pattern of light through an image sensor, and restore the shape of the object to be measured through electronic calculations rather than optical methods. There is a difference in

Meanwhile, a conventional digital holographic microscope using a single wavelength laser light source has a problem that the minimum unit length of measurement of an object is limited to the wavelength of the laser. In order to compensate for this, another conventional digital holographic microscope using a laser light source of two or more wavelengths has a problem in that the manufacturing cost of the microscope is high, and a three-dimensional shape of an object cannot be obtained in real time.

In addition, the above-described conventional digital holographic microscopes generate CGH (Computer Generated Hologram) with a computer in order to restore the shape of the object to be measured, then display it on a spatial light modulator (SLM), and The 3D hologram image of the object was acquired by illuminating the reference light. However, this method not only required the use of an expensive spatial light modulator (SLM), but was merely digitizing a special film in the above-described optical holographic microscope, and technical limitations were clear.

In order to solve the problems of such conventional digital holographic microscopes, for example, Korean Patent Laid-Open Publication No. 10-2016-0029606 (hereinafter referred to as "public prior art") proposes a digital holographic microscope and a digital holographic image generation method. Hereinafter, a brief look at the disclosed prior art.

2 is a block diagram showing in detail a two-wavelength digital holography microscope apparatus according to the prior art.

Referring to FIG. 2, the conventional two-wavelength digital holographic microscope apparatus includes a mixed light source unit 10, a wavelength division unit 20, an interference fringe acquisition unit 30, an object unit 40, an image sensor unit 50, It includes an image storage unit 60, a control unit 70, and an object shape restoration unit 80.

The mixed light source unit 10 includes a mixed light source light emitting unit 11 and a light source unit lens 12. The mixed light source light emitting unit 11 emits mixed light having a wavelength band distributed in several bands that are not single. The light source unit lens 12 optically adjusts the mixed light generated by the mixed light source light emitting unit 11 and makes it incident on the wavelength dividing unit 20.

The wavelength splitter 20 includes a first light splitter 21, a first filter plate 22, a second filter plate 23 and a first reflector 24. The first light splitter 21 receives the mixed light incident from the mixed light source unit 10 and divides it into two lights. At this time, the first light splitter 21 serves to divide the incident mixed light in different directions to proceed. The first filter plate 22 receives one of the lights divided by the first light splitter 21 to obtain a first ray having a predetermined single wavelength. Here, light input to the first filter plate 22 is filtered while passing through the first filter plate 22, and a first ray of light having a single wavelength determined according to the characteristics of the first filter plate 22 is obtained. The second filter plate 23 receives the remaining light from the light split by the first light splitter 21 in the same manner as the first filter plate 22, and receives a second light having a wavelength different from that of the first light ray. Acquire a ray. And the second ray is sent to the interference fringe acquisition unit 30. The first reflector 24 serves to receive the first light beam acquired from the first filter plate 22 and reflect it to the interference fringe acquisition unit 30.

The interference fringe acquisition unit 30 includes a second light splitter 31, a third light splitter 32, a second reflector 33, a third filter plate 34, and a third reflector 35. The second light splitter 31 receives the first light input from the wavelength splitter 20 and divides it into a first object light and a first reference light. At this time, the second light splitter 31 serves to divide the incident first light rays in different directions to proceed. The third light splitter 32 receives the second light in the same manner as the second light splitter 31 and splits it into a second object light and a second reference light. The second reflector 33 receives the first reference light and transmits the reflected first reference light to the second light splitter 31. The third filter plate 34 may receive the first reference light divided by the second light splitter 31 and send it to the second reflector 33, and receive the reflected first reflected reference light and send it to the second light splitter. In addition, the third filter plate 34 prevents the progress of the second object light from reaching the second reflector 33 when the second object light reaches the second light splitter 31 and is split into light, so that a part of the light proceeds toward the second reflector 33. . To this end, the third filtering plate 34 is a filtering plate having the same characteristics as the first filtering plate 22 in transmitting light. The third reflector 35 receives the second reference light and sends the reflected second reference light to the third optical splitter 32, where the second reflector 33 and the third reflector 35 are the control unit 70 ), it is possible to implement an off-axis hologram by configuring the angle to be adjustable according to the control.

Meanwhile, the first object light and the second object light obtained as described above are converted into first and second reflective object lights through the following processes, and are sent to the image sensor unit 50. The second optical splitter 31 causes the light of the first object divided as described above to be incident on the object to be measured mounted on the object part 40, and is divided and sent from the third optical splitter 32. Light is incident on the object to be measured. In this case, the reflected light obtained by reflecting the first object light incident on the object to be measured is referred to as first reflective light. In addition, the reflected light that reflects the second object light incident from the object to be measured is referred to as second reflective object light. The second optical splitter 31 receives the reflected first and second reflective light as described above and sends them to the third optical splitter 32. The third optical splitter 32 transmits the first and second reflective object light received as described above to the image sensor unit 50 again.

In addition, the first reflection reference light and the second reflection reference light obtained as described above are transmitted to the image sensor unit 50 through the following process. Specifically, the second light splitter 31 receives the first reflection reference light reflected from the second reflector 33 and sends it to the third light splitter 32. The third light splitter 32 receives the first reflection reference light sent from the second light splitter 31 and the second reflection reference light reflected from the third reflection body 35 as described above, and the image sensor unit 50 Send to Accordingly, from the third optical splitter 32, the first reflective object light, the first reflective reference light, the second reflective object light, and the second reflective reference light are all sent to the image sensor unit 50 in the same direction, and then interfere with each other. An interference fringe is created.

On the other hand, the second reflector 33 and the third reflector 35 are angled according to the control of the controller 70 in order to form an off-axis system in which light rays of different wavelengths form different interference patterns. It is characterized in that it can be adjusted in multiple directions. That is, as the angles of the second reflector 33 and the third reflector 35 become different from each other, the first reflective reference light reflected from the second reflector 33 and the second reference reflected from the third reflector 35 When a separation occurs in the direction of the light, when the first reflection reference light and the second reflection reference light are combined with the first reflection object light and the second reflection object light reaching the image sensor unit 50 to form an interference pattern, each wavelength Differently, a deaxial interference pattern is formed.

The objective part 40 includes an object holder 41 and an objective lens 42. The object cradle 41 fixes the object to be measured to the cradle to be measured, and the objective lens 42 optically adjusts the light of the first object and the light of the second object incident on the object to be measured.

The image sensor unit 50 projects the interference fringe acquired by the interference fringe acquisition unit 30 onto a digital image sensor, measures the projected interference fringe using the digital image sensor, and measures the measured value as a discrete signal. Convert to Usually, the recording of the interference pattern is called a hologram. Various image sensors such as CCD may be used as such a digital image sensor.

The image storage unit 60 stores interference pattern information converted into discrete signals by the image sensor unit 50 in various storage media such as a memory or a disk device.

The control unit 70 implements the above-described off-axis system and adjusts the position and angle of the second reflector 33 and the third reflector 35 in order to obtain the interference fringe. ) And controlling the objective part 40, such as adjusting the objective lens 42 to control the first and second object light incident on the object to be measured, and the interference pattern is measured The image sensor unit 50 is controlled to convert the information into a discrete signal, and the image storage unit 60 is controlled to store the interference fringe information converted into a discrete signal.

The object shape restoration unit 80 includes a phase information acquisition unit 81, a thickness information acquisition unit 82, and a shape restoration unit 83. The phase information acquisition unit 81 acquires phase information of the interference fringe for the first ray and phase information of the interference fringe for the second ray using the interference fringe information, respectively, and the thickness information acquisition unit 82 Obtains thickness information of the object to be measured using the phase information, and the shape restoration unit 83 restores a real-time three-dimensional shape of the object to be measured using the thickness information. In this case, the thickness information of the object to be measured includes information on the difference between the paths of the object light and the reference light, respectively. The interference fringes are formed when the object light and the reference light overlap because of the difference in the optical path between the object light and the reference light.

According to the disclosed prior art including the above, it is possible to improve measurement resolution and secure real-time image acquisition. However, the following problems still arise.

In the prior art disclosed first, since a mixed light source having a wavelength band distributed in several bands is used, the wavelength dividing unit 20 divides the first and second light sources having different wavelengths to obtain at least two single wavelengths. To do this, the first filter plate 22, the second filter plate 23, and the first reflector 24 must be used.

In addition, the interference fringe acquisition unit 30 is a third light splitter 32 for dividing the second light source, a third reflector 35 for reflecting the second light source, and the second light source is a second reflector 33 A third filter plate 34 to block incident on the vehicle should be additionally used.

Accordingly, the structure of the microscope is complicated, and this entails various problems such as an increase in manufacturing cost and an increase in design complexity. Therefore, a new method for solving the above-described problem is required while using a light source of a single wavelength.

Republic of Korea Patent Publication No. 10-2016-0029606 Republic of Korea Patent Publication No. 10-2010-0095302 Republic of Korea Patent Publication No. 10-2012-0014355 Korean Patent No. 10-1139178 Korean Patent No. 10-1441245 U.S. Patent No. 7,649,160

The present invention is to solve the problems of the prior art as described above, and it is intended to accurately check the presence or absence of a substrate by accurately generating 3D shape information of an object to be measured by acquiring only one hologram.

In particular, an object of the present invention is to generate information about a reference light and curvature aberration information of an object light objective lens from one hologram, and correct the obtained object hologram in consideration of the information to generate 3D shape information of an object to be measured with improved accuracy.

In addition, the present invention aims to solve the problem of a complex optical device structure and a considerable high cost associated therewith.

Furthermore, the present invention seeks to detect defects in these structures with high probability by accurately obtaining a three-dimensional shape of an ultrafine structure such as a TFT and a semiconductor.

An embodiment of the present invention includes a carrier that fixes a substrate and is formed to be movable with the fixed substrate, a first transfer unit that moves the carrier on which the substrate is fixed in a first direction, and the first transfer unit is disposed therein. A first transfer chamber, at least one deposition unit for depositing a material on the substrate moved by the first transfer unit, and inspecting the substrate by being disposed on a movement path of the substrate moved by the first transfer unit, An inspection unit for restoring 3D information on the surface of the substrate to inspect the presence or absence of the deposited substrate, a light source unit emitting a single wavelength light to provide to the inspection unit, and the single wavelength light emitted from the light source unit to the inspection unit It provides an in-line deposition inspection system with a transmitting optical fiber.

In an embodiment of the present invention, the inspection unit may be disposed inside the first transfer chamber, and the light source unit may be disposed outside the first transfer chamber.

In an embodiment of the present invention, a first rack for loading a substrate to be processed, a first inversion chamber disposed between the first rack and the first transfer chamber, and connected to the first transfer chamber, , A second transfer chamber through which the first transfer unit passes, a second rack for unloading a processed substrate, and a second inversion chamber disposed between the second transfer chamber and the second rack, One or more inspection units may be disposed between the first and second inversion chambers.

In one embodiment of the present invention, the first transfer unit may move the carrier in the first direction through the first transfer chamber and the second transfer chamber.

In one embodiment of the present invention, a vacuum chamber for disposing the deposition unit therein may be further included, and the vacuum chamber may be connected to the first transfer chamber or the second transfer chamber.

In an embodiment of the present invention, the inspection unit includes a collimator for collimating the single wavelength light emitted from the light source unit, a light splitter for dividing the single wavelength light passing through the collimator into object light and reference light, the An object light objective lens for passing the object light divided by a light splitter, a reference light objective lens for passing the reference light divided by the light splitter, an optical mirror for reflecting the reference light passing through the reference light objective lens, and the object An interference fringe formed by passing through an optical objective lens and passing through the object light reflected from the surface of the substrate and the reference light reflected by the optical mirror passes through the object light objective lens and the reference light objective lens, and is transmitted to the optical splitter, is recorded. An image sensor, wherein the in-line deposition system receives and stores an image file generated by converting the interference fringe from the image sensor, and generates a digital reference hologram calculated from the object hologram obtained from the image file. And, it may further include a processor for restoring the 3D information of the substrate by calculating a phase information difference from the first information of the object hologram and the second information of the digital reference hologram.

Other aspects, features, and advantages other than those described above will become apparent from the detailed content, claims and drawings for carrying out the following invention.

According to an embodiment of the present invention made as described above, according to the present invention, it is possible to accurately generate 3D shape information of an object to be measured by acquiring only one hologram.

In particular, by generating information on the reference light and curvature aberration information of the object light objective lens from one hologram, and correcting the obtained object hologram in consideration of the information, 3D shape information of the object to be measured with improved accuracy may be generated.

In addition, it is possible to solve the problem of complex optical device structures and thus considerable high cost.

Furthermore, by accurately acquiring the three-dimensional shape of ultrafine structures such as TFTs and semiconductors, defects in these structures can be detected with high probability.

Of course, the scope of the present invention is not limited by these effects.

1 is a block diagram showing in detail a two-wavelength digital holographic microscope apparatus according to the disclosed prior art.
2 is a diagram schematically illustrating an in-line deposition inspection system according to an embodiment of the present invention.
3A is a block diagram showing a schematic configuration of a holographic restoration apparatus according to a first embodiment of the present invention.
3B is a block diagram showing a schematic configuration of a holographic restoration apparatus according to a second embodiment of the present invention.
4A and 4B are diagrams for explaining an external shape of an exemplary object to be measured.
5 is an example of an image of a part of an object to be measured.
6 is a diagram illustrating a frequency component of an image of a portion of the object to be measured shown in FIG. 5.
7 is a diagram illustrating a method of extracting frequency components corresponding to an actual image from the frequency components shown in FIG. 6.
8A is a diagram showing the intensity of digital reference light.
8B is a diagram showing a phase of a reference light.
8C is a diagram showing the intensity of correction light.
8D is a diagram showing the phase of the correction light.
9 is a diagram illustrating an exemplary real hologram.
10 and 11 are diagrams for explaining a method of determining, by a processor, a curvature aberration correction term from an intermediate hologram according to an embodiment of the present invention.
12 is a diagram illustrating an example of a three-dimensional shape of an object to be measured generated from a hologram.
13 is a flowchart illustrating a method of generating 3D shape information of an object to be measured performed by a holographic restoration apparatus according to an embodiment of the present invention.
14 and 15 are flowcharts illustrating a method of removing noise of a holographic restoration apparatus according to embodiments of the present invention.

Hereinafter, various embodiments of the present disclosure will be described in connection with the accompanying drawings. Various embodiments of the present disclosure may be modified in various ways and may have various embodiments, and specific embodiments are illustrated in the drawings and related detailed descriptions are described. However, this is not intended to limit the various embodiments of the present disclosure to a specific embodiment, it should be understood to include all changes and/or equivalents or substitutes included in the spirit and scope of the various embodiments of the present disclosure. In connection with the description of the drawings, similar reference numerals have been used for similar elements.

Expressions such as "include" or "may include" that may be used in various embodiments of the present disclosure indicate the existence of a corresponding function, operation, or component that is disclosed, and additional one or more functions, operations, or It does not limit components, etc. In addition, in various embodiments of the present disclosure, terms such as "include" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, It is to be understood that it does not preclude the possibility of the presence or addition of one or more other features or numbers, steps, actions, components, parts, or combinations thereof.

In various embodiments of the present disclosure, expressions such as "or" include any and all combinations of words listed together. For example, "A or B" may include A, may include B, or may include both A and B.

Expressions such as "first", "second", "first", or "second" used in various embodiments of the present disclosure may modify various elements of various embodiments, but do not limit the corresponding elements. Does not. For example, the expressions do not limit the order and/or importance of corresponding elements. The above expressions may be used to distinguish one component from another component. For example, a first user device and a second user device are both user devices and represent different user devices. For example, without departing from the scope of the rights of various embodiments of the present disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

When a component is referred to as being "connected" or "connected" to another component, the component is directly connected to or may be connected to the other component, but the component and It should be understood that new other components may exist between the other components. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it will be understood that no new other component exists between the component and the other component. Should be able to

The terms used in various embodiments of the present disclosure are only used to describe a specific embodiment, and are not intended to limit the various embodiments of the present disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which various embodiments of the present disclosure belong.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in various embodiments of the present disclosure, ideal or excessively formal It is not interpreted in meaning.

2 is a diagram schematically illustrating an in-line deposition inspection system 1 according to an embodiment of the present invention.

An in-line deposition inspection system 1 according to an embodiment of the present invention is a system for manufacturing devices including deposited materials, comprising an inspection unit capable of inspecting the presence or absence of defects in the deposited devices. It is characterized. Here, the devices may be electronic devices or semiconductor devices, such as optoelectronic devices or display devices. As an embodiment, the device may be an organic light emitting display device including a substrate M on which organic materials are deposited. The substrate M may include a material selected from the group consisting of a combination of materials that can be coated by a deposition process, such as glass, metal, polymer, ceramic, compound materials, and carbon fiber materials.

2, the in-line deposition inspection system 1 includes a deposition unit 600, a loading unit 400, an unloading unit 500, a first transfer unit 210, an inspection unit 300, and a light source unit ( 310) and a processor 390.

The loading unit 400 may include a first rack 410 and a first inversion chamber 420. Further, although not shown, an introduction chamber (not shown) may be further disposed between the first rack 410 and the first inversion chamber 420.

The first rack 410 is loaded with a number of substrates (M) before deposition is performed, and the introduction robot provided in the introduction chamber (not shown) grabs the substrate (M) from the first rack 410 and the carrier 100 After placing the substrate M on ), the carrier 100 to which the substrate M is attached is moved to the first inversion chamber 420.

A first reversing chamber 420 is provided adjacent to the introduction chamber (not shown), and a first reversing robot located in the first reversing chamber 420 reverses the carrier 100 to transfer the carrier 100 to the first transfer unit. Attach to (210). In this specification, the inversion means changing the position so that the first surface of the carrier 100 facing the top is facing the bottom. However, the present invention is not now limited, and may mean rotating the carrier 100 so that the horizontally disposed carrier 100 is disposed vertically. In other words, reversal may mean changing the first loaded carrier 100 to a different arrangement state from the loaded arrangement state.

Meanwhile, the configuration of the unloading unit 500 is configured opposite to that of the loading unit 400 described above. That is, the substrate M and the carrier 100 on which the deposition has been completed are inverted in the second inversion chamber 520 and transferred to the take-out chamber (not shown), and the take-out robot moves in the take-out chamber (not shown). After the substrate M and the carrier 100 are taken out, the substrate M is separated from the carrier 100 and loaded on the second rack 510. The carrier 100 separated from the substrate M is transferred to the loading unit 400 through the second transfer unit 220.

The first transfer unit 210 may move the carrier 100 to which the substrate M is fixed in the first direction. Here, the first direction may be a direction from the loading unit 400 to the unloading unit 500. The first transfer unit 210 is disposed inside the first transfer chamber 201 and the second transfer chamber 202 to move the carrier 100 from the first transfer chamber 201 to the second transfer chamber 202 I can make it.

The in-line deposition inspection system 1 may have one or more transfer chambers. For example, it may include a first transfer chamber 201 and a second transfer chamber 202, as shown, one disposed between the first transfer chamber 201 and the second transfer chamber 202 The above additional transfer chambers 203, 204, 205 may be further provided.

Meanwhile, the deposition unit 600 performs a function of depositing a material on the substrate M that is moved by the first transfer unit 210. As an embodiment, the deposition unit 600 may be disposed inside the first transfer chamber 201 or the second transfer chamber 202 to deposit a material on the moving substrate M. As another embodiment, the deposition unit 600 may be disposed inside the vacuum chamber 610 provided separately from the transfer chamber. In this case, the vacuum chamber 610 may be connected to at least one of the first transfer chamber 201, the second transfer chamber 202, or the additional transfer chambers 203, 204 and 205.

When the vacuum chamber 610 is separately provided, the vacuum chamber 610 may be connected to the transfer chamber by having a gate valve. The vacuum chamber 610 may include one or more alignment units 112. The alignment unit 112 may adjust the position of the substrate M with respect to the mask. As another embodiment, the alignment unit 112 may be connected to the mask frame to adjust the position of the mask with respect to the substrate M.

Meanwhile, the in-line deposition inspection system 1 may further include a maintenance vacuum chamber 710 or a mask shelf 720 positioned near the vacuum chamber 610 in which deposition is performed. The maintenance vacuum chamber 710 may be provided for maintenance of the deposition unit 600, specifically, a deposition source. When maintenance of the deposition source is required, the in-line deposition inspection system 1 may move the deposition source to the maintenance vacuum chamber 710 to fill the material or perform maintenance. Further, the mask shelf 720 may be provided for storage of replacement masks or masks that need to be stored for specific deposition steps. Although not shown, the mask shelf 720 may be connected to a mask cleaning chamber (not shown), and at this time, vacuum tight sealing between the mask cleaning chamber (not shown) and the mask shelf 720 for mask cleaning. ) Can be provided.

Meanwhile, according to an embodiment of the present invention according to FIG. 1, the carrier 100 to which the substrate M is fixed is at least the transfer chambers 201 to 205, preferably the first transfer unit 210, The carrier 100 is sequentially moved to the loading unit 400, the transfer chambers 201 to 205 and the unloading unit 500, and the carrier 100 separated from the substrate M in the unloading unit 500 is a second transfer unit ( 220) can be returned to the loading unit 200. In this case, the second transfer unit 220 may move the carrier 100 from which the substrate M is separated after deposition is completed in a direction opposite to the first direction.

The inspection unit 300 is disposed on the movement path of the substrate M that is moved by the first transfer unit 210 to inspect the substrate M, but the deposited substrate M by restoring 3D information on the substrate surface You can check the presence of abnormalities. As shown, the in-line deposition inspection system 1 may include one or more inspection units 300 between the loading unit 400 and the unloading unit 500, through which the substrate M ) Can be checked for abnormalities. In other words, one or more inspection units 300 may be disposed between the first inversion chamber 420 and the second inversion chamber 520.

As an embodiment, the inspection unit 300 may be provided in a number corresponding to the number of deposition steps. For example, suppose that a three-layer thin film is stacked on the substrate M through a first deposition process, a second deposition process, and a third deposition process through the in-line deposition inspection system 1, the inspection unit 300 Three pieces of silver may be disposed on a path in which the substrate M after each step is moved. However, the present invention is not limited thereto, and it goes without saying that the inspection unit 300 does not correspond to each step and may be provided in a smaller number than this. In addition, the inspection unit 300 may be disposed at a location other than the moving path of the substrate M, at this time, the in-line deposition inspection system 1 transfers the substrate M to the location of the inspection unit 300 It may be further provided with a separate transfer means for making.

The inspection unit 300 is disposed inside the transfer chambers 201 to 205 to perform the inspection while the substrate M, which has been deposited from the deposition unit 600, is moving through the transfer chambers 201 to 205. have. In the in-line deposition inspection system 1 according to an embodiment of the present invention, since the inspection unit 300 is disposed inside the transfer chambers 201 to 205, the inspection can be performed in real time without a separate inspection process. Thus, the process time can be efficiently reduced.

In this case, the light source unit 310 for providing light to the inspection unit 300 may be disposed outside the transfer chambers 201 to 205. The light source unit 310 emits light of a single wavelength and provides it to the inspection unit 300, for example, the light source unit 310 may be a laser source. The light source unit 310 may be disposed inside the transfer chambers 201 to 205 together with the inspection units 300, but the light source unit 310 includes the transfer chambers 201 to 205 for efficient arrangement in the deposition process. Can be placed outside. Since the light source unit 310 may be spatially separated from the inspection unit 300, it is possible to minimize a restriction on selection of light required to obtain 3D shape information, specifically a wavelength of light.

Meanwhile, the in-line deposition inspection system 1 may include an optical fiber 311 for transmitting light to the inspection unit 300 when the light source unit 310 is disposed outside. The optical fiber 311 may perform a function of transmitting the single wavelength light emitted from the light source unit 310 to the inspection unit. The optical fiber 311 may transmit single wavelength light to the collimator 320 of the inspection unit 300 to be described later. Since the optical fiber 311 performs a function of transmitting only for a specific wavelength, noise of the input light transmitted from the light source unit 310 can be removed, and when the light is emitted, the beam size is enlarged and provided to the collimator 320. I can.

Hereinafter, the inspection unit 300 according to an embodiment of the present invention will be described in more detail. First, a two-wavelength digital holography microscope apparatus according to the prior art will be described, and then the inspection unit 300 according to an embodiment of the present invention will be described.

3A is a block diagram showing a schematic configuration of an inspection unit 300A according to the first embodiment of the present invention.

In the present invention, the inspection unit 300A refers to a holography restoration apparatus, and hereinafter, it will be described unified as a holography restoration apparatus 300A. The'holographic restoration apparatus 300A' may mean a device that acquires a hologram of an object to be measured (hereinafter, referred to as a'object hologram'), and analyzes and/or displays the obtained object hologram.

For example, the holographic restoration apparatus 300A may be a device disposed on a semiconductor manufacturing line to obtain an object hologram of a semiconductor to be produced, and determine whether the semiconductor is integrity from the obtained object hologram. However, this is merely an example and the spirit of the present invention is not limited thereto.

Meanwhile, in the present invention, the'object hologram' is a hologram that can be generated from an image obtained by the holographic restoration apparatus 300A, and may mean a hologram before various processes by the holographic restoration apparatus 300A are performed. have. A detailed description of this will be described later.

Referring to FIG. 3A, the holographic restoration apparatus 300A according to the first embodiment of the present invention includes a collimator 320 for collimating a single wavelength light emitted from the light source unit 310, and a single wavelength passing through the collimator 320. A light splitter 330 for dividing light into object light O and reference light R, object light objective lens 340 for passing object light O divided by light splitter 330, and light splitter 330 ) To pass through the reference light (R) divided by the reference light objective lens (360), the optical mirror (370) reflecting the reference light (R) that has passed through the reference light objective lens (360), the object light through the objective lens (340) Thus, the object light O reflected from the surface of the object to be measured 350 and the reference light R reflected by the optical mirror 370 pass through the object light objective lens 340 and the reference light objective lens 360, respectively. It may include an image sensor 380 which is a recording medium for recording an image transmitted to the optical splitter 330 and a processor 390 for processing an image acquired by the image sensor 380. Here, the object to be measured 350 may be a substrate (M). Hereinafter, the substrate (M) will be described as the object to be measured 350.

In this case, the processor 390 may generate 3D information of the object to be measured 350 from the image acquired by the image sensor 380. A detailed description of the operation of the processor 390 will be described later.

3B is a block diagram showing a schematic configuration of a holographic restoration apparatus 300B according to a second embodiment of the present invention.

Referring to FIG. 3B, the holographic restoration apparatus 300B according to the second embodiment of the present invention includes a collimator 320 for collimating a single wavelength light emitted from the light source unit 310, and a single wavelength passing through the collimator 320. After the light splitter 330 that divides the light into object light (O) and reference light (R), and the object light (O) divided by the light splitter 330 passes through the measurement target 350, the measurement target ( An object light objective lens 340 that passes through the object transmitted light T including information of 350), a second optical mirror 372 that reflects the transmitted object light T that has passed through the object light objective lens 340, a light splitter A reference light objective lens 360 for passing the reference light R divided by 330, a first optical mirror 370 for reflecting the reference light R passing through the reference light objective lens 360, and a first optical mirror ( Reference light transmitted to the second optical splitter 332 and the second optical splitter 332 through which the reference light R reflected by 370 and the object transmitted light T reflected by the second optical mirror 372 are respectively transmitted An image sensor 380 that records an image formed by (R) and transmitted object light T, and a processor 390 that processes an image obtained by the image sensor 380 may be included.

Of course, even in this second embodiment, the processor 390 may generate 3D information of the object to be measured 350 from the image acquired by the image sensor 380. A detailed description of the operation of the processor 90 will be described later.

The object light O is measured in the holographic restoration apparatus 300A according to the first exemplary embodiment of the present invention and the holography restoration apparatus 300B according to the second exemplary embodiment shown in FIGS. 3A and 3B, respectively. It is reflected from the target object 350 (the embodiment of Fig. 3A) or the object light O transmits the measurement object 350 (the embodiment of Fig. 3B) and some components accordingly (for example, The second optical mirror 372 and the second optical splitter 332 of the embodiment of FIG. 3B have substantially the same configuration, except for the additional use and arrangement of some components accordingly.

In particular, it should be noted that the image is acquired by the image sensor 380 and has the same characteristic in that the processor 390 generates the reference light R from the acquired image.

Hereinafter, the holographic restoration apparatuses 300A and 300B according to the first and second embodiments of the present invention will be collectively referred to as the holographic restoration apparatus 300.

Meanwhile, the processor 390 of the holography restoration apparatus 300 according to an embodiment of the present invention may include all types of devices capable of processing data. For example, the processor 390 may refer to a data processing device embedded in hardware having a circuit physically structured to perform a function represented by a code or instruction included in a program. The processor 390 may be included in the inspection unit 300 and disposed inside the transfer chambers 201 to 205, but may be provided in a separate configuration and disposed outside the transfer chambers 201 to 205.

As an example of such a data processing device built into the hardware, a microprocessor, a central processing unit (CPU), a processor core, a multiprocessor, and an application-specific integrated (ASIC) Circuit) and processing devices such as a Field Programmable Gate Array (FPGA) may be covered, but the scope of the present invention is not limited thereto.

In addition, the image sensor 380 according to an embodiment of the present invention may be implemented with at least one image sensor such as a charge coupled device (CCD) and a Complimentary Metal-Oxide Semiconductor (CMOS).

4A and 4B are diagrams for explaining an external shape of an exemplary measurement target object 350. When the measurement object 350 is the substrate M, deposition materials may be formed on the substrate M along the mask pattern. Since the thin film pattern deposited on the substrate M has a rather complex shape, the simplified pattern shown in FIGS. 4A and 4B will be described below for convenience of description.

As shown in FIGS. 4A and 4B, the object to be measured 350 may include structures 51A to 51I in a rectangular parallelepiped shape disposed on one surface at predetermined intervals. In other words, the object to be measured 350 may include structures 51A to 51I in a rectangular parallelepiped shape protruding in the Z direction on a plane parallel to the X-Y plane.

Hereinafter, the holography restoration apparatus 300 irradiates the object light O in a direction perpendicular to the surface on which the rectangular parallelepiped structures 51A to 51I of the measurement object 350 are disposed, and the image of the measurement object 350 It will be described on the premise of obtaining.

First, the image sensor 380 according to an embodiment of the present invention may acquire an image of an object to be measured 350.

In the present invention, the'Image' of the object to be measured 350 is information on the intensity at each position of the hologram (U0(x,y,0)) of the object to be measured 350 (ie | (U0(x,y,0)| ² ) may be included, and may be expressed as Equation 1 below.

[Equation 1]

Here, the object hologram Uo(x,y,0) represents the phase information at each x,y point of the object to be measured, and x, y are coordinates in the space where the object to be measured is placed, perpendicular to the object light (O). Represents the coordinates defining the plane, O(x,y) and R(x,y) represent object light (O) and reference light (R), respectively, and O*(x,y) and R*(x, y) denotes the complex conjugate of the object light O and the reference light R, respectively.

For example, the image sensor 380 may acquire an image as shown in FIG. 5 for a portion of the object to be measured 350 shown in FIGS. 4A and 4B (eg, a portion including 51A and 51B). I can.

Since the image acquired by the image sensor 380 includes intensity information at each position of the object hologram U0(x,y,0) as described above, the image sensor 380 It may be different from the image of the object to be measured 350 (that is, taken only with the object light O).

Referring to Equation 1, the object hologram (U0(x,y,0)) does not include the object light (0) including the phase information of the object to be measured 350 at each point and the phase information of the object to be measured. It may be generated by interference of the non-referred reference light R.

In addition, the object hologram (U0(x,y,0)) is the object light objective lens 340 in addition to the phase information (that is, height information of the object) at each point (that is, each x, y point) of the object to be measured 350. ) And noise (eg, speckle noise due to the use of photons of the laser), etc. may be further included.

Accordingly, the processor 390 according to an embodiment of the present invention may perform various calculation processes as described below in order to remove the above-described error and noise from the image acquired by the image sensor 380.

The processor 390 according to an embodiment of the present invention may check the frequency components of an image acquired by the image sensor 380. For example, the processor 390 may perform a 2D Fourier Transform on the image to check the frequency components of the image.

In other words, the processor 90 stores the frequency components included in the image including the intensity information for each location of the object hologram (U0(x,y,0)) (that is, |(U0(x,y,0)| ² )). In this case, the image may include a frequency component corresponding to a real image, a frequency component corresponding to an immaginary image, and a DC component.

Of course, the image may further include various components in addition to the above-described three components (a frequency component corresponding to an actual image, a frequency component corresponding to a virtual image, and a DC component). For example, the image may further include frequency components due to noise. However, this is merely an example and the spirit of the present invention is not limited thereto.

The processor 390 according to an embodiment of the present invention may extract only the components corresponding to the actual among the identified frequency components. In this case, the processor 390 may extract components corresponding to the actual image in various ways.

For example, the processor 390 extracts components (hereinafter, peak components) having a peak value among frequency components included in the image, and extracts a peak component corresponding to an actual image among the extracted peak components. Components within the frequency difference of firing can be extracted as components corresponding to the actual reality.

In this case, the processor 390 may determine components corresponding to the actual image in various ways based on the peak component corresponding to the actual image. For example, the processor 90 may determine frequency components in a cross region including a peak component as components corresponding to the actual image among frequency components corresponding to the actual image. In this case, the length of the cross region from the peak component may be determined based on a frequency component corresponding to the actual image and a distance difference value between the origin and the corresponding frequency component. For example, however, this is merely an example and the spirit of the present invention is not limited thereto.

In an optional embodiment, the processor 390 may extract only components corresponding to a real image among frequency components included in a hologram using an automatic real image spot-position extraction algorithm.

In the present invention,'extracting' a specific frequency component may mean extracting the frequency of the corresponding frequency component and the magnitude (or intensity) of the corresponding frequency component.

6 is a diagram illustrating a frequency component of an image for a portion of the object to be measured 350 shown in FIG. 5.

As described above, the processor 390 can check the frequency components of the image acquired by the image sensor 380, and accordingly, the processor 390 is a frequency component 911 corresponding to a real image and a frequency component corresponding to a virtual image. Various frequency components including 912 and DC component 913 can be identified.

In addition, the processor 390 may extract only the frequency component 911 corresponding to the actual image among the identified components. At this time, the processor 390 removes noise from a frequency component corresponding to the actual image. Specifically, the processor 390 removes the frequency component located in the direction of the interference fringe and in the normal direction of the interference fringe as noise, so that, for example, as shown in FIGS. 7A, 7B, 7C, and 7D, Frequency components in the cross region centered on the peak component can be determined as components corresponding to the actual state. At this time, the direction of the cross region is rotated according to the direction of the interference fringe.

The processor 390 according to an embodiment of the present invention may generate digital reference light from frequency components corresponding to the actual image extracted by the above-described process. Looking at this in more detail, the processor 390 may calculate the propagation direction and wave number of the digital reference light based on frequency components corresponding to the actual image. In other words, the processor 390 may calculate the wave number vector of the digital reference light.

In addition, the processor 390 generates digital reference light based on the propagation direction and wave number (or wave number vector) of the digital reference light, and calculates the conjugate term of the digital reference light R(x,y) generated as in Equation 2 below. By obtaining, correction light Rc(x,y) can be generated.

[Equation 2]

In this case, R(x,y) denotes digital reference light generated based on frequency components corresponding to the actual image, and Rc(x,y) denotes a correction light.

The processor 390 extracts a normal line of the interference fringe and direction lines Line1 and Line2 parallel to the interference fringe in response to the peak component 911P from among the frequency components 911 corresponding to the actual image. The processor 390 determines a region including Line1 and Line2 as noise regions (Noise1, Noise2, Noise3, and Noise4). The processor 390 may extract frequency components distributed in regions excluding noise regions. The processor 90 may extract frequency components corresponding to the actual image from which the noise is removed using a pattern excluding the noise region. As illustrated in FIG. 7C, the processor 90 may remove noise using a cross-shaped pattern Pattern1 that excludes frequency components distributed in Line1 and Line2. At this time, the processor 90 generates a cross-shaped pattern (Pattern1) based on a predetermined ratio of the distance difference value between the origin component 913 and the frequency component 911 corresponding to the actual image, for example, 1/3 times R. You can decide.

The processor 90 may set various patterns for removing the noise area. As shown in FIG. 6D, noise of a frequency component corresponding to the actual image may be performed by using a pattern (Pattern2) whose width is wider as it approaches the peak component of the frequency component 911 corresponding to the actual image.

Since the digital reference light (R(x,y)) and the correction light (Rc(x,y)) are in a conjugate relationship, the intensity is the same as shown in FIGS. 8A and 8C, and as shown in FIGS. 8B and 8D. Likewise, the phase can be reversed. Here, FIG. 8A is a diagram showing the intensity of the digital reference light R(x,y), FIG. 8B is a diagram showing the phase of the reference light, and FIG. 8C is a diagram showing the intensity of the correction light Rc(x,y). Fig. 8D is a diagram showing the phase of the correction light.

The generated correction light Rc(x,y) may be used for correction of a real hologram Um(x,y,0) to be described later.

Meanwhile, the'digital reference light' is light having the same properties as the reference light R generated by the above-described optical splitter 330 from light of a single wavelength, and the processor 390 is restored from the image acquired by the image sensor 380 It could be a virtual light.

The processor 390 according to an embodiment of the present invention may generate a real hologram based on frequency components corresponding to the real image extracted by the above-described process. For example, the processor 390 may generate a real hologram as shown in FIG. 9 by performing an inverse 2D Fourier transform on frequency components corresponding to the real image.

In this case, the hologram can be represented by Equation 3 below.

[Equation 3]

Here, Um(x,y,0) represents a real hologram, O(x,y) represents an object light (O), and R*(x,y) represents a complex conjugate of the reference light (R).

Meanwhile, the real hologram Um(x,y,0) includes information on the reference light R and errors due to aberration of the object light objective lens 340 in addition to information on the height of the object to be measured 350. Can include.

Therefore, the processor 390 according to an embodiment of the present invention takes into account the effect of the reference light R and the error due to the aberration of the object light objective lens 340 from the actual hologram Um(x,y,0). It is possible to generate a correction hologram Uc(x,y,0).

For example, as shown in Equation 4 below, the processor 90 has a term for corrected light (Rc(x,y)) and a term for curvature aberration correction (Rca(x)) in a real hologram (Um(x,y,0)). The correction hologram Uc(x,y,0)) can be generated by multiplying by ,y)).

[Equation 4]

Here, Uc(x,y,0) denotes a correction hologram from which information on the reference light R and aberration information of the object light objective lens 340 are removed, and Um(x,y,0) denotes a real hologram, Rc(x,y) denotes a term for correction light, and Rca(x,y) denotes a term for curvature aberration correction.

Meanwhile, the processor 390 according to an embodiment of the present invention may generate a term (Rca(x,y)) for the above-described curvature aberration correction in various ways.

For example, the processor 390 is actually the hologram (Um(x,y,0)) multiplied by only the term (Rc(x,y)) for the corrected light (hereinafter, referred to as the intermediate hologram). A dimensional shape may be generated, and a term for curvature aberration correction (Rca(x,y)) may be generated from the generated 3D shape.

Looking at this in more detail, the processor 390 may determine at least one parameter for determining the curvature aberration correction term from the three-dimensional shape of the measurement target object 350 generated from the intermediate hologram. In this case, the parameter may include, for example, a coordinate and a radius of a center point defining a hemispherical curved surface.

10 and 11 are diagrams for explaining a method of determining, by the processor 390, a curvature aberration correction term from an intermediate hologram according to an embodiment of the present invention.

For convenience of explanation, it is assumed that the image sensor 380 obtained an image of the rectangular parallelepiped structure 51D of FIG. 3B, and that the processor 390 generated an intermediate hologram of the structure 51D according to the above-described process. do. In addition, it is assumed that the three-dimensional shape 920 of the structure 51D generated from the intermediate hologram of the structure 51D is as shown in FIG. 10.

Under the above assumption, the processor 390 according to an embodiment of the present invention may determine at least one parameter for determining a curvature aberration correction term from the 3D shape 920. For example, the processor 390 may determine the coordinates (Cx, Cy) of the center point of the hemispherical curved surface and the radius (r) of the curved surface from the curve on the II section of the three-dimensional shape 920 as shown in FIG. 11 as parameters. . In this case, the processor 390 according to an embodiment of the present invention may determine the position and/or direction of the cut surface such that the cut surface such as the I-I cross-section includes the center point of the 3D shape 920 (ie, the center point of the hemispherical shape). In addition, the processor 390 may determine that a cut surface such as an I-I cross-section is parallel to the traveling direction of the object light 0.

The processor 390 according to an embodiment of the present invention may generate (or determine) a curvature aberration correction term based on at least one parameter determined by the above-described process. For example, the processor 390 generates a curved surface in 3D space by referring to the coordinates (Cx, Cy) of the center point of the curved surface and the radius (r) of the curved surface, and reflected in the phase correction of each x,y point from the generated curved surface. The curvature aberration correction term can be generated (or determined) by generating information.

In an alternative embodiment, the processor 390 may determine a correction term from an intermediate hologram of an object to be measured (eg, an object having the same z value in all x and y coordinates) whose shape is known in advance.

In the case of a measurement target object whose shape is known in advance, since the z value at each x and y point is known in advance, the processor 390 determines the three-dimensional shape of the measurement target object generated from the intermediate hologram and the known shape of the measurement target object. The correction term can also be determined by checking the difference between the z values at each x and y points. However, this is merely an example and the spirit of the present invention is not limited thereto.

The processor 390 according to an embodiment of the present invention may generate a three-dimensional shape of the measurement target object 350 based on the correction hologram Uc(x,y,0). In other words, the processor 390 may calculate the height of the object at each x and y point in the z direction.

For example, the processor 90 may convert the correction hologram Uc(x,y,0) into information on the reconstructed image plane. In this case, the reconstructed image plane means a virtual image display plane corresponding to a distance corresponding to the distance between the object to be measured and the image sensor by the processor, and may be a virtual plane calculated and simulated by the processor 90.

The processor 390 may calculate the height of the object at the x and y points in the z direction from the reconstructed information in consideration of the reconstructed image plane as shown in FIGS. 12A, 12B, and 12C. FIG. 12A shows the results of restoring without removing noise from the frequency component, FIG. 12B shows the results of removing noise using a cross-shaped pattern (Pattern1), and FIG. 12C shows the results of removing noise using Pattern2. . A1, A2, and A3 represent the height values in the Z direction in a flat graph. It can be seen that A1 has a large change in the height value in the z direction because the noise is not removed, and A2 and A3 have little change in the height value in the z direction.

When using a cross-shaped pattern, the processor 390 may extract a frequency component according to Equation 5 below.

[Equation 5]

12A, 12B, and 12C illustrate three-dimensional shapes of two rectangular parallelepiped structures 51A and 51B disposed on the object 350 to be measured.

13 is a flowchart illustrating a method of generating 3D shape information of an object to be measured 350 performed by the holographic restoration apparatus 300 according to an embodiment of the present invention. Hereinafter, descriptions of contents overlapping with those described in FIGS. 2 to 12 will be omitted, but will be described with reference to FIGS. 2 to 12.

The holographic restoration apparatus 300 according to an embodiment of the present invention may acquire an image of the object to be measured 350 (S1201).

In the present invention, the'Image' of the object to be measured 350 is information on the intensity at each position of the hologram (U0(x,y,0)) of the object to be measured 350 (ie | (U0(x,y,0)| ² ) may be included, and may be expressed as in Equation 1 above.

For example, the holographic restoration apparatus 300 acquires an image as shown in FIG. 5 for a portion of the object to be measured 350 shown in FIGS. 4A and 4B (eg, a portion including 51A and 51B). can do.

Since the image acquired by the holographic restoration apparatus 300 includes intensity information at each position of the object hologram U0(x,y,0) as described above, the holographic restoration apparatus 300 is obtained. It may be different from the image of the object to be measured 350 in one general (that is, taken only with the object light O).

Referring to Equation 1, the object hologram (U0(x,y,0)) does not include the object light (0) including the phase information of the object to be measured 350 at each point and the phase information of the object to be measured. It may be generated by interference of the non-referred reference light R.

In addition, the object hologram (U0(x,y,0)) is the object light objective lens 340 in addition to the phase information (that is, height information of the object) at each point (that is, each x, y point) of the object to be measured 350. ) And noise (eg, speckle noise due to the use of photons of the laser), etc. may be further included.

Accordingly, the holographic restoration apparatus 300 according to an embodiment of the present invention may perform the calculation process of steps S1202 to S1207 to remove the above-described error and noise from the image obtained by the holographic restoration apparatus 300. .

The holographic restoration apparatus 300 according to an embodiment of the present invention may check frequency components of an image obtained by the holographic restoration apparatus 300 (S1202). For example, the holographic restoration apparatus 300 may perform a 2D Fourier Transform on an image to check frequency components of the image.

In other words, the holographic restoration apparatus 300 includes the intensity information for each location of the object hologram U0(x,y,0) (that is, |(U0(x,y,0)| ² )). In this case, the image may include a frequency component corresponding to a real image, a frequency component corresponding to an immaginary image, and a DC component.

Of course, the image may further include various components in addition to the above-described three components (a frequency component corresponding to an actual image, a frequency component corresponding to a virtual image, and a DC component). For example, the image may further include frequency components due to noise. However, this is merely an example and the spirit of the present invention is not limited thereto.

The holographic restoration apparatus 300 according to an embodiment of the present invention may extract only components corresponding to the actual image among the identified frequency components (S1203). In this case, the holographic restoration apparatus 300 may extract components corresponding to the actual image in various ways.

For example, the holographic restoration apparatus 300 extracts components (hereinafter referred to as peak components) having a peak value among frequency components included in the image, and peaks corresponding to the actual image among the extracted peak components. Components within the frequency difference between the component and the firing can be extracted as components corresponding to the actual reality.

In this case, the holographic restoration apparatus 300 may determine components corresponding to the actual image in various ways based on the peak component corresponding to the actual image. For example, the holographic restoration apparatus 300 may determine frequency components in the cross region centered on the peak component corresponding to the actual image as components corresponding to the actual image. However, this is merely an example and the spirit of the present invention is not limited thereto.

In an optional embodiment, the holographic restoration apparatus 300 may extract only components corresponding to a real image from among frequency components included in the hologram using an automatic real image spot-position extraction algorithm.

In the present invention,'extracting' a specific frequency component may mean extracting the frequency of the corresponding frequency component and the magnitude (or intensity) of the corresponding frequency component.

Referring back to FIG. 6, the holography restoration apparatus 300 may check the frequency components of the image acquired by the holography restoration apparatus 300, and accordingly, the holography restoration apparatus 300 may determine the frequency components 911 corresponding to the actual image. ), various frequency components including a frequency component 912 and a DC component 913 corresponding to the virtual image can be identified.

In addition, the holographic restoration apparatus 300 may extract only the frequency component 911 corresponding to the actual image among the identified components. At this time, the holographic restoration apparatus 300 may determine frequency components 911B in the cross region centered on the peak component 911A corresponding to the actual image as components corresponding to the actual image, as illustrated in FIG. 7.

The holography restoration apparatus 300 according to an embodiment of the present invention may generate digital reference light from frequency components corresponding to the actual image extracted by the above-described process (S1204). Looking at this in more detail, the holographic restoration apparatus 300 may calculate the propagation direction and wave number of the digital reference light based on frequency components corresponding to the actual image. In other words, the holographic restoration apparatus 300 may calculate a wave number vector of the digital reference light.

In addition, the holographic restoration apparatus 300 generates digital reference light based on the propagation direction and wave number (or wave number vector) of the digital reference light, and the digital reference light R(x,y) generated as in Equation 2 The correction light Rc(x,y) can be generated by finding the conjugate term.

Since the digital reference light (R(x,y)) and the correction light (Rc(x,y)) are in a conjugate relationship, the intensity is the same as shown in FIGS. 8A and 8C, and as shown in FIGS. 8B and 8D. Likewise, the phase can be reversed. Here, FIG. 8A is a diagram showing the intensity of the digital reference light R(x,y), FIG. 8B is a diagram showing the phase of the reference light, and FIG. 8C is a diagram showing the intensity of the correction light Rc(x,y). Fig. 8D is a diagram showing the phase of the correction light.

The generated correction light Rc(x,y) may be used for correction of a real hologram Um(x,y,0) to be described later.

Meanwhile, the'digital reference light' is light having the same properties as the reference light R generated by the above-described light splitter 330 from light of a single wavelength, and the holography restoration apparatus 300 is obtained by the holography restoration apparatus 300. It may be a virtual light restored from an image.

The holographic restoration apparatus 300 according to an embodiment of the present invention may also generate a real hologram based on frequency components corresponding to the real image extracted by the above-described process (S1204). For example, the holographic restoration apparatus 300 may generate a real hologram as shown in FIG. 9 by performing an inverse 2D Fourier transform on frequency components corresponding to a real image. In this case, the hologram can be represented as in Equation 3 above.

The holographic restoration apparatus 300 according to an exemplary embodiment of the present invention may generate an intermediate hologram to generate a term (Rca(x,y)) for curvature aberration correction (S1205). For example, the holographic restoration apparatus 300 may generate an intermediate hologram by multiplying the actual hologram Um(x,y,0) by the term Rc(x,y) for the correction light. The generated intermediate hologram may be used to generate curvature aberration correction information in step S1206.

The holographic restoration apparatus 300 according to an embodiment of the present invention generates a three-dimensional shape of the object to be measured 350 from the intermediate hologram generated in step S1205, and a term for correction of curvature aberration from the generated three-dimensional shape ( Rca(x,y)) may be generated (S1206). Looking at this in more detail, the holography restoration apparatus 300 may determine at least one parameter for determining a curvature aberration correction term from a three-dimensional shape of the measurement target object 350 generated from an intermediate hologram. In this case, the parameter may include, for example, a coordinate and a radius of a center point defining a hemispherical curved surface.

Referring again to FIGS. 10 and 11, a method of determining a curvature aberration correction term from an intermediate hologram by the holographic restoration apparatus 300 according to an embodiment of the present invention will be described. For convenience of explanation, the holographic restoration apparatus 300 obtained an image of the rectangular parallelepiped structure 51D of FIG. 4B, and the holographic restoration apparatus 300 creates an intermediate hologram of the structure 51D according to the above-described process. Is assumed to have been created. In addition, it is assumed that the three-dimensional shape 920 of the structure 51D generated from the intermediate hologram of the structure 51D is as shown in FIG. 10.

Under the above-described assumption, the holographic restoration apparatus 300 according to an embodiment of the present invention may determine at least one parameter for determining a curvature aberration correction term from the three-dimensional shape 920. For example, the holographic restoration apparatus 300 determines the coordinates (Cx, Cy) of the center point of the hemispherical curved surface and the radius (r) of the curved surface from the curve on the II section of the three-dimensional shape 920 as shown in FIG. I can. At this time, the holographic restoration apparatus 300 according to an embodiment of the present invention may determine the position and/or direction of the cut surface such that the cut surface such as the II cross-section includes the center point of the three-dimensional shape 920 (that is, the center point of the hemispherical shape). . In addition, the holographic restoration apparatus 300 may determine such that a cut surface such as an I-I cross-section is parallel to the traveling direction of the object light 0.

The holographic restoration apparatus 300 according to an embodiment of the present invention may generate (or determine) a curvature aberration correction term based on at least one parameter determined by the above-described process. For example, the holographic restoration apparatus 300 generates a curved surface in a three-dimensional space by referring to the coordinates (Cx, Cy) of the center point of the curved surface and the radius (r) of the curved surface, and performs phase correction of each x,y point from the generated curved surface. The curvature aberration correction term may be generated (or determined) in a manner of generating information to be reflected.

In an alternative embodiment, the holographic restoration apparatus 300 may determine a correction term from an intermediate hologram of an object to be measured (eg, an object having the same z value in all x and y coordinates) whose shape is known in advance.

In the case of a measurement object whose shape is known in advance, since the z value at each x and y point is known in advance, the holographic restoration apparatus 300 includes the three-dimensional shape of the measurement object generated from the intermediate hologram and the known measurement object. The correction term can also be determined by checking the difference between the z values at each x and y point of the shape. However, this is merely an example and the spirit of the present invention is not limited thereto.

The holographic restoration apparatus 300 according to an embodiment of the present invention is a real hologram (Um(x,y,0)) in consideration of an error caused by the aberration of the object light objective lens 340 and the influence of the reference light R. The correction hologram Uc(x,y,0) may be generated from (S1207). For example, as shown in Equation 4 above, the holographic restoration apparatus 300 includes a term for correction light (Rc(x,y)) and a term for curvature aberration correction (Rca) in a real hologram (Um(x,y,0)). By multiplying (x,y)), a correction hologram Uc(x,y,0)) can be generated. At this time, the term (Rc(x,y)) for the correction light may be generated in step S1204, and the term for curvature aberration correction (Rca(x,y)) may be generated in step S1206.

The holographic restoration apparatus 300 according to an embodiment of the present invention may generate 3D shape information of the object to be measured 350 based on the correction hologram Uc(x,y,0) (S1208). In other words, the holographic restoration apparatus 300 may calculate the height of the object at each x and y point in the z direction.

For example, the holographic restoration apparatus 300 may convert the correction hologram Uc(x,y,0) into information on the reconstructed image surface. In this case, the reconstructed image plane means a virtual image display plane corresponding to a distance corresponding to the distance between the object to be measured and the image sensor by the processor, and may be a virtual plane calculated and simulated by the holographic restoration apparatus 300. .

The holographic restoration apparatus 300 may calculate the height in the z direction of the object at x and y points as shown in FIG. 12 from the restored information in consideration of the reconstructed image plane. In FIG. 12, the three-dimensional shape of the two rectangular parallelepiped-shaped structures 51A and 51B disposed on the object to be measured 350 is illustrated as an example.

14 and 15 are flowcharts illustrating a method of removing noise of the holographic restoration apparatus 300 according to embodiments of the present invention.

The holographic restoration apparatus 300 according to an embodiment of the present invention may extract only components corresponding to the actual image among the identified frequency components (S1203).

In S12031, the holographic restoration apparatus 300 determines a first frequency component corresponding to a real image included in the image, a second frequency component corresponding to a virtual image, and a third frequency component corresponding to the origin.

In S12032, the holography restoration apparatus 300 calculates a direction and a normal direction of the interference fringe from the first frequency component, and determines the direction of the interference fringe and a frequency component located in the normal direction as noise.

In S12033, the holographic restoration apparatus 300 removes noise from the first frequency component and extracts a frequency component corresponding to the actual image.

In another embodiment, the holographic restoration apparatus 300 may set a pattern from which noise has been removed, and extract a frequency component corresponding to an actual image using the pattern.

In S12034, the holographic restoration apparatus 300 determines a first frequency component corresponding to a real image included in the image, a second frequency component corresponding to a virtual image, and a third frequency component corresponding to the origin.

In S12035, the holographic restoration apparatus 300 generates a cross-region pattern including a peak component of the first frequency component. In S12036, the holography reconstruction apparatus 300 extracts frequency components included in the cross region pattern from among the first frequency components.

Equation to which the cross area pattern is applied is as follows. The holographic restoration apparatus 300 may extract frequency components included in the cross region pattern according to Equation 6 below.

[Equation 6]

Here, ms is the size of the cross region pattern, xc is the X coordinate of the peak component, and yc is the Y coordinate of the peak component.

The size of the cross region pattern is determined based on the distance between the origin component and the actual image and the corresponding frequency component, but the size of the cross region pattern can be adjusted for efficient removal of the noise component. The size of the cross region pattern can be optimized through an iterative noise removal process.

In another embodiment, in order to more efficiently remove noise, the holographic restoration apparatus 300 may assign different weights according to the position of the filtering region through hemispherical filtering. For example, the holographic restoration apparatus 300 may multiply a weight smaller than 1 as the distance from the center increases.

[Equation 7]

The embodiment according to the present invention described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program may be recorded in a computer-readable medium. In this case, the medium may store a program executable by a computer. Examples of media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical image sensors such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, And a ROM, RAM, flash memory, and the like, and may be configured to store program instructions.

Meanwhile, the computer program may be specially designed and configured for the present invention, or may be known and usable to those skilled in the computer software field. Examples of the computer program may include not only machine language codes produced by a compiler but also high-level language codes that can be executed by a computer using an interpreter or the like.

As described above, the holographic restoration apparatus 300 according to an embodiment of the present invention, that is, the inspection unit 300 may accurately generate 3D shape information of an object to be measured by obtaining one hologram. . The above-described inspection unit 300 can simplify components while generating accurate 3D shape information through the above-described methods, so that it is disposed inside the in-line deposition equipment to perform inspection in real time on the in-line process. To be.

The specific implementations described in the present invention are examples and do not limit the scope of the present invention in any way. For brevity of the specification, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connection or connection members of the lines between the components shown in the drawings exemplarily represent functional connections and/or physical or circuit connections, and in an actual device, various functional connections that can be replaced or additionally Connections, or circuit connections, may be represented. In addition, if there is no specific mention such as "essential", "important", etc., it may not be an essential component for the application of the present invention.

Accordingly, the spirit of the present invention is limited to the above-described embodiments and should not be defined, and all ranges equivalent to or equivalently changed from the claims to be described later as well as the claims to be described later are the scope of the spirit of the present invention. It will be said to belong to.

1: In-line deposition inspection system
201: first transfer chamber
210: first transfer unit
220: second transfer unit
310: light source
300: inspection unit
390: processor

Claims (1)

A carrier that fixes the substrate and is movable with the fixed substrate;
A first transfer unit for moving the carrier on which the substrate is fixed in a first direction;
A first transfer chamber in which the first transfer unit is disposed;
At least one deposition unit for depositing a material on the substrate moved by the first transfer unit;
An inspection unit disposed on a movement path of the substrate that is moved by the first transfer unit to inspect the substrate, restoring 3D information on the surface of the substrate to inspect the deposited substrate for abnormality;
A light source unit that emits single wavelength light and provides it to the inspection unit; And
An in-line deposition inspection system comprising; an optical fiber for transmitting the single wavelength light emitted from the light source to the inspection unit.

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