KR102040017B1 - System for measuring sample height with non-contact - Google Patents

Abstract

Embodiments of the present invention relate to a height measuring system comprising a light source part including a light source for irradiating light, a sample stage in which a sample is disposed, a light detecting part for detecting a light signal by receiving the light, and a data processing device for calculating a height of the sample on the basis of the detected light signal, wherein the light received by the photodetector includes the light which has passed around the sample or the light which has incompletely passed through the sample.

Description

Non-contact sample height measurement system {SYSTEM FOR MEASURING SAMPLE HEIGHT WITH NON-CONTACT}

The present invention relates to a technique for measuring the height of a sample, and more particularly, in a region where a light signal of a light source can be detected (that is, a scan region) in which a cross section of a sample parallel to the optical path is projected (that is, projected). And a height measuring system for measuring a height of a sample based on an optical signal of light detected in a region other than the region (i.e., a detection region).

Recently, due to the development of ultra fine technology, there is an urgent need for information on the surface shape of microstructures or materials in the field of electronics and / or advanced materials. An electron microscope is used for the minute observation of such nm unit, and a scanning electron microscope (SEM) is typical.

A scanning electron microscope is an observation device that uses the principle of scanning electrons in a sample to collect secondary electrons protruding from the sample surface, and filling the scanned area with a monitor pixel to generate an image of the sample surface. The face (tens of nm) can be observed.

On the other hand, when an electron beam scanned by an electron gun of a scanning electron microscope and focused at a high energy is incident on the surface of an insulator sample (for example, an organic material or a bio sample), the primary electrons incident on the sample do not escape and the inside of the sample does not escape. Accumulation may occur in the battery. As such, the primary electrons accumulated in the sample increase the yield of secondary electrons scattered back from the sample surface when the sample surface is negatively charged, thereby mutual repulsion between the incident electrons and the secondary electrons. Action is increased. As a result, the image of the sample surface is severely brightened or distorted due to the increased mutual repulsive action, so that it is difficult to obtain a high quality clear image.

In order to solve the problem of the scanning electron microscope which requires a sample in such a vacuum state, a scanning electron microscope (hereinafter, referred to as an 'external scanning electron microscope') capable of observing a sample in a non-vacuum state (for example, the atmosphere). Is called). Such an external scanning electron microscope irradiates an electron beam to a sample present in the atmosphere and observes the sample while moving horizontally. When the electron beam is irradiated onto the sample because the sample is in the atmosphere, the electrons accumulated on the surface of the sample are neutralized with the cations ionized from the particles in the atmosphere, so that the charging effect is extremely low. Therefore, there is an advantage in that a good quality image can be generated and observed for the organic sample without any additional treatment.

Since an external scanning electron microscope places the sample in the atmospheric state, in order to minimize the dispersion by the atmosphere during the scanning of the electron beam into the sample, the distance at which the electron beam is exposed to the atmosphere, that is, at the boundary between the vacuum and non-vacuum states The sample is approximated with an external scanning electron microscope. In general, an external scanning electron microscope separates a vacuum state from a non-vacuum state using a thin membrane. Therefore, when the sample is approached indefinitely to the outside air scanning electron microscope, a situation in which the sample collides with the permeable membrane and the sample is deformed or the permeable membrane is damaged may occur.

Therefore, it is very important to accurately measure the height of the sample to prevent the sample and / or the permeable membrane from being damaged due to the collision between the permeable membrane and the sample.

Patent Registration Publication No. 10-1186103 Patent Registration Publication No. 10-1505745

According to one aspect of the invention, a system may be provided for measuring the height of a sample by using light to scan a cross section of the sample disposed between the light source and the photodetector.

Height measurement system according to an aspect of the present invention includes a light source unit including a light source for irradiating light; A sample stage on which a sample is placed; A light detector for detecting the light signal by receiving the light; The apparatus may include a data processing device configured to calculate a projection area for the sample based on the detected optical signal and determine the height of the projection area as the height of the sample. Here, the light received by the photodetector includes light that has passed around the sample, or light that has incompletely passed the sample.

In one embodiment, the photodetector comprises a photodetector for receiving the light; And a connection part configured to change a height of a projection area by the sample with respect to one end surface of the photodetector.

In one embodiment, the data processing device may be further configured to determine the maximum value as the height of the sample when the height of the one or more projective areas is calculated.

In one embodiment, the sample stage may be located parallel to the light path between the light source and the photodetector.

In one embodiment, the data processing device may be further configured to set the position of the sample stage as a reference for sample height measurement.

In one embodiment, the data processing device may be further configured to correct the height of the measured sample based on a pre-stored reference table. Here, the reference table includes measurement results for reference samples whose height information is known in advance.

In one embodiment, the light source may further include a patterning unit disposed on the optical path that proceeds to the sample. Here, the patterning unit is configured to pattern the light in a preset pattern.

In one embodiment, the data processing device may be further configured to measure a height of a sample based on the preset pattern and the detected optical signal.

In one embodiment, the data processing apparatus may be further configured to calculate the projection area based on the detected intensity of the optical signal.

In an embodiment, the light source unit may further include a filter disposed on an optical path through which light from the light source proceeds to a sample. Here, the filter is configured such that the wavelength of the output light is lower than the wavelength of the input light.

In one embodiment, the light source unit further comprises a first lens located on the light path between the light source and the sample stage, the light detector is a second lens located on the light path between the sample stage and the photodetector It may further include.

In one embodiment, the sample stage is further configured to be movable horizontally or vertically.

In one embodiment, when the optical signal is detected, the data processing apparatus compares the shape of the sample formed based on the detected optical signal with a scan area that is an optical signal reception range of the photodetector to determine whether the shape of the sample exceeds the scan area. And if the shape of the sample is determined to exceed the scan area, move the sample to produce a partial image including excess unscanned portions, and combine the partial images to obtain an image of the entire cross section of the sample It can be further configured to calculate the height of.

In one embodiment, the data processing apparatus may be configured to calculate a distance between the shape of the sample and a frame surrounding the scan area to determine that the shape of the sample exceeds the scan area when the distance is zero.

In one embodiment, the data processing apparatus may be further configured to determine that the shape of the sample exceeds the scan area when light is irradiated from the light source and the photodetector does not respond.

According to an aspect of the present invention, a height measuring system includes an area except for a portion (ie, a projection area) in which a cross section of a sample parallel to the optical path is projected in an area (that is, a scan area) where an optical signal of a light source can be detected. That is, the height of the sample is measured based on the optical signal of light detected in the detection area. Here, the sample is arranged to block at least some of the light directed to the photodetector. As a result, the light source and the CCD are located on the upper surface of the sample, and thus, images may be acquired from the side surface, unlike conventional optical interference, optical triangulation, auto focusing, confocal microscopy, and the like. Only height information can be obtained quickly.

In addition, the height information can be quickly confirmed by the measurement using the transmission method on the side of the sample with a very simple configuration, without the non-essential operation for the height measurement such as 3D rendering the overall sample shape.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

BRIEF DESCRIPTION OF DRAWINGS To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the drawings required in the description of the embodiments are briefly introduced below. It is to be understood that the drawings below are for the purpose of describing the embodiments herein and are not intended to be limiting. In addition, some elements to which various modifications, such as exaggeration and omission, may be shown in the following drawings for clarity of explanation.
1 is a conceptual block diagram of a height measurement system 1, according to one embodiment of the invention.
2 is a view for explaining a projection area by a sample and a detection area of a photodetector according to an embodiment of the present invention.
3A and 3B are views for explaining the structure of a height measuring system for performing a height measuring operation according to an embodiment of the present invention.
4 is a diagram for describing an operation of measuring a height of a sample based on one or more projected areas according to an embodiment of the present invention.
5 is a diagram for describing an operation of measuring a sample height having high accuracy according to an embodiment of the present invention.
6A to 6C are diagrams for describing a divided scan operation according to an embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprise" or "have" are intended to embody the described features, regions, numbers, steps, actions, components, and / or components, and include one or more other features, regions, numbers, It is not intended to exclude the presence or addition of steps, actions, components, and / or components.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal sense unless clearly defined herein. .

In this specification, a scan operation refers to a series of operations that irradiate an optical signal toward a sample to obtain information (eg, including a shape, etc.) related to the sample (or cross section of the sample).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual block diagram of a height measurement system 1, according to one embodiment of the invention.

Referring to FIG. 1, the system 1 includes data including a light source unit 100, a sample stage 310 on which a sample 300 is disposed, a light detector 500, and a controller 710 and an image processor 750. A processing apparatus 700. In one embodiment, the system 1 may further include a patterning portion (not shown) for outputting patterned light.

The height measurement system 1 according to the embodiments may be entirely hardware or may have aspects that are partially hardware and partially software. For example, the components included in the system 1 may collectively refer to hardware and software related thereto for processing data in a specific format and content and / or for electronic communication. That is, as used herein, "unit", "module", "device" or "system" and the like refer to hardware, a combination of hardware and software, or a computer-related entity such as software. For example, parts, modules, devices, or systems herein refer to running processes, processors, objects, executables, threads of execution, programs, and / or computers. computer, but is not limited thereto. For example, both an application running on a computer and a computer may correspond to a part, module, device, system, or the like herein.

Each component of the height measuring system 1 according to the embodiments is not intended to necessarily refer to a separate component that is physically distinct. That is, although illustrated in FIG. 1 as separate blocks separated from each other, according to an exemplary embodiment, some or all of the light source unit 100, the sample stage 310, the photodetector 500, and the data processing apparatus 700 are the same. May be integrated into, or electrically connected to, a device (eg, a display device).

In addition, the units 710 and 750 are merely functionally divided devices according to operations performed by the data processing apparatus 700 in which they are implemented, and do not necessarily mean separate elements separated from each other.

The light source unit 100 includes a light source 110 for irradiating light.

The light source 110 may output white light or polychromatic light mixed with light having a plurality of wavelengths. The light source 110 may include, for example, a solid state laser, a fiber laser, a halogen lamp, an LED, and the like, but is not limited thereto.

Irradiation of light may be performed by various setting of light sources of the light source 110. For example, it may be configured to irradiate light by receiving a light irradiation command of the data processing apparatus, to irradiate light, to irradiate light based on a predetermined setting condition, or to irradiate light by various methods such as continuously irradiating light. .

In one embodiment, the light source unit 100 may further include an objective lens 130 for converting the light output from the light source 110 into parallel light.

In one embodiment, the light source unit 100 may further include a filter (not shown) for filtering the light output from the light source 110. The filter of the light source unit 100 is positioned on an optical path where light from the light source 100 travels to the sample 300, and is configured such that the wavelength of the output light is lower than the wavelength of the input light. For example, the filter of the light source unit 100 may include a band pass filter (BPS), but is not limited thereto. As such, by using light having a lower wavelength value in height measurement, the resolution can be improved.

The sample stage 310 is configured to place the sample 300 on the top surface of the sample stage 310. The sample stage 310 may be made of metal such as a stud. In this case, the sample stage 310 may be grounded through a separate holder (not shown).

The sample stage 310 causes the sample 300 to be disposed between the light source 110 and the photodetector 500. That is, the sample 300 of the sample stage 310 is disposed at a position where the output light of the light source 110 may pass around the sample 300 or may be incident on one end surface of the sample 300. The light incident on one side of the sample 300 may be blocked according to the material of the sample 300, or may pass through the sample 300 to the photodetector 510. As such, the light reaching the photodetector 500 is affected by the sample 300 disposed on the optical path. This will be described in more detail with reference to FIG. 2 below.

The photodetector 500 includes a photodetector 510 that receives an output light of the light source unit 100 and detects an optical signal. In one embodiment, the photodetector 510 may be a charge-coupled device (CCD) capable of capturing the entire area of one cross section of the sample 300. In this case, the photodetector 510 converts an optical signal transmitted into the photodetector 510 into an electrical signal based on the intensity of the light, and the electrical signal converts an analog signal into a digital signal (for example, For example, an optical signal may be detected through an analog-digital converter (ADC). In addition, an image of one side of the sample 300 may be generated. For example, as illustrated in FIG. 2, an image having the scan area A as a frame and the projected area B as the shape of the sample 300 may be generated.

In the region where the photodetector 510 can receive light (the region capable of scanning a cross section of the sample), the light from the light source unit 100 may pass through the sample 300 and reach the photodetector 510. An area that may incompletely pass through the sample 300 to reach the photodetector 510, or virtually extend to reach the photodetector 510 if it is not possible to proceed directly to the photodetector 510 by the sample 300. Which is referred to herein as a scan area. That is, the optical signal can be detected within the scan area range.

2 is a view for explaining a projection area by a sample and a detection area of a photodetector according to an embodiment of the present invention.

Referring to FIG. 2, the entire frame including the sample 300 is a scan area A in which the photodetector 500 can detect an optical signal to scan the sample 300.

The photodetector 510 may receive light including at least one of output light passing through the sample 300 and output light passing incompletely through the sample 300. The scan area A, which is an area where the photodetector 510 can receive the output light output from the light source unit 100, can receive the light influenced by the sample 300 in the progress to the photodetector 510. Area (which is referred to herein as “projection area (B)”), and area that can receive light unaffected by sample 300 (herein referred to as “detection area (C)”. ) "). Here, the influence on the progress of the light by the sample 300 is the sample 300, including blocking the progression by the sample 300, or incompletely passing through the sample 300 by the material constituting the sample 300, etc. In comparison with the light passing through the ()) it includes the effect caused by the cause associated with the sample (300).

In an embodiment, as shown in FIG. 2, when the sample 300 is made of an opaque material that blocks light, light emitted from the light source unit 100 and incident on one end surface of the sample 300 is blocked from traveling. do. As a result, the photodetector 510 positioned behind the light path may not receive light in the projection area B corresponding to one cross section of the sample 300. On the other hand, the light output from the light source unit 100 and incident on a region other than one cross section of the sample 300 (for example, light passing through the sample 300) is not blocked by the sample 300. Such light may be received at the photodetector 510, forming a detection area (C).

Therefore, when the sample 300 is made of an opaque material that blocks light, the photodetector 510 may receive light in the scan area A except for the projection area B. have.

In one embodiment, when the sample 300 is made of a translucent material that partially obstructs the progress of light, the photodetector 510 may receive light that has passed incompletely through the sample 300. That is, the photodetector 510 may receive light even in the projection area B. However, in the above embodiment, the intensity of light received in the projection area B of FIG. 2 is lower than the intensity of light reaching the photodetector 510 without passing through the sample 300.

Therefore, when height measurement is performed on the sample 300 made of a translucent material, the light passing through the sample 300 and the light passing through the sample 300 incompletely may be received by the photodetector 510. As a result, the photodetector 510 may receive light in the entire range of the scan area A. FIG.

As such, the intensity of the optical signal received by the photodetector 510 corresponds to the cross-sectional shape of the sample. When generating an image for the scan area A, the scan area A is a frame, and the projection area B is used. An image having the shape of the sample can be generated.

In one embodiment, the photodetector 500 may further include a connector 530 coupled to the photodetector 510. The connection part 530 is configured to change the height of the projection area by the sample 300 with respect to one end surface of the photodetector 510. In one example, the connector 530 may be configured to be rotatable by a motor. In another example, the connector 530 may be configured to be rotatable by a component controlled by the controller 710 to cause a rotational motion. The rotation angle of the photodetector 510 is changed by the connector 530.

In one embodiment, the photodetector 500 may further include a condenser lens 550 for condensing the light traveling in parallel so that the photodetector 510 receives the light better.

The data processing apparatus 700 includes a controller 710 and an image processor 750.

The controller 710 controls the overall operation of the system 1, for example, the operation of the sample stage 310 and / or the rotation of the connector 530 (that is, the rotation angle of the photodetector 510). Can be controlled.

Here, the rotation angle represents the angle between the cross section of the current region that receives the light from the photodetector 510 from one axis that virtually connects the sample 300 and the photodetector 510. When the rotation angle is 0 degrees, the cross section of the current area that receives light in the photodetector 510 represents a relationship perpendicular to the virtual one axis. Symbols (+,-) indicate the rotational direction of the photodetector 510, and indicate whether to rotate in the direction toward the sample 300 and away from the sample 300. The code may be set in various ways. In one example, the direction in which the light travels may be set to-, and in another example, the direction in which the light may travel is set to +.

The image processor 750 may acquire data and calculate various results. In an embodiment, the image processor 750 may calculate the projection area based on the optical signal detected by the photodetector 510. For example, the image processor 750 may project the projection area B associated with one end surface of the sample 300 based on characteristics of the optical signal, such as the presence or absence of the optical signal detected by the photodetector 510, and / or the like. Alternatively, the detection region C can be detected.

In some embodiments, the image processor 750 may acquire an image generated by the CCD 510 and perform various operations associated with the image. In another exemplary embodiment, the image processor 750 may generate an image of the side surface of the sample 300 based on the detected projection area B and / or the detection area C. Furthermore, the height of the sample 300 may be calculated based on the image of the side surface of the sample 300, so that the height of the sample 300 may be measured.

In one embodiment, the image processor 750 may calculate the projection area based on the presence or absence of the detected optical signal when the sample 300 is made of a completely opaque material. In another embodiment, the image processor 750 may calculate the projection area even when the sample 300 is made of an opaque material. The intensity of light reaching the photodetector 510 without passing through the sample 300 is greater than the intensity of light reaching the photodetector 510 incompletely through the sample 300. In turn, the projection area can be obtained based on the intensity of the light received by the photodetector.

3A and 3B are diagrams for describing a structure of a height measuring system in which a height measuring operation is performed, according to an embodiment of the present invention. 3A is a plan view of the system at the time of the height measurement operation, and FIG. 3B is a side view of the system at the time of the height measurement operation. Hereinafter, the height measurement operation will be described in detail using a sample 300 made of an opaque material that blocks light for clarity of explanation.

3A and 3B, the light source portion 100 and the photodetector 510 of the system 1 are located in parallel. The sample stage 310 allows the sample 300 to be positioned at a point for blocking, for example, some or all of the light output from the light source unit 100. In one example, the sample stage 310 may be located parallel to the optical path of the parallel light refracted by the lens 130.

Due to this position structure, when the sample 300 is small in size (e.g., smaller than the optical path range refracted by the lens 130), the output light in the system 1 is distributed throughout the cross section of the sample 300. Can be incident. That is, the entire cross section of the sample 300 may be scanned at once.

The light incident on one end surface of the sample 300 is blocked from traveling light. On the other hand, light passing through the sample 300 continues to be received by the photodetector 510.

In one embodiment, when the output light of the light source unit 100 runs perpendicular to one end surface of the sample 300 (that is, the rotation angle of the photodetector 510 is 0 °), the photodetector 510 In the reception area, substantially the same projection area is formed in one cross section of the sample 300. The image processor 750 calculates the projection area of FIG. 2 based on the optical signal detected by the photodetector 510. As illustrated in FIG. 2, when the size of the sample 300 is smaller than the scan area range, the projection area has the same shape, size, area, and the like as the cross section of the sample 300. The image processor 750 calculates the height of the projection area as the height of the sample 300. Therefore, the system 2 can know the height of the sample by calculating the height of the projective area, and can finally measure the height of the sample.

In one embodiment, the image processor 750 may set the position of the sample stage 310 in the absence of the sample 300 as a reference for measuring the sample height.

In some embodiments, when the sample stage 310 is irradiated with light to an entire cross section of the sample 300 without being irradiated with light as shown in FIG. 3B, the image processor 750 may be configured to display the sample 300. The bottom surface of the projection area is determined as a reference for the height measurement, and the height of the sample 300 is measured based on the reference for the height measurement.

In another exemplary embodiment, the image processor 750 may calculate a projection area formed by one cross section of the sample 300 and one cross section of the sample stage 310. In this case, the image processor 750 may calculate a projected area for the sample 300 by filtering a pre-stored sample stage projected area corresponding to the sample stage 310.

4 is a diagram for describing an operation of measuring a height of a sample based on one or more projected areas according to an embodiment of the present invention.

The projection area for one cross section of the sample 300 may be different according to the rotation angle of the photodetector 510. As shown in FIG. 4, the projection area when the rotation angle of the photodetector 510 is 0 ° corresponds to the height cross section actually used for measuring the height of the sample 300. On the other hand, as the angle of rotation of the photodetector 510 increases, the degree of inconsistent with the height cross section actually used increases.

In one embodiment, the system 1 may control the connection 530 such that the rotation angle is 0 °. In this case, the system 1 determines the height of the calculated projection area as the height of the sample 300.

In another embodiment, the system 1 may control the angle of rotation to calculate the height of one or more projection areas. As shown in FIG. 4, as the height (or size, cross-sectional area, etc.) of the projection area increases, the size of the rotation angle decreases. As a result, when the height and the like of the projection area are the largest, the rotation angle is 0 °.

Therefore, when one or more projected areas are calculated by the rotation of the connection unit 530, the image processor 750 determines the maximum value as the height of the sample 300.

5 is a diagram for describing an operation of measuring a sample height having high accuracy according to an embodiment of the present invention.

In addition, the system 1 may use the moire effect for more accurate height measurements.

When the observation target is composed of a pattern P smaller than the resolution of a general microscope as shown in FIG. 5, it is difficult to accurately generate an optical image of the sample 300 to be observed due to the limitation of the resolution. However, knowing the information about a specific pattern Q in advance can produce an optical image for the sample 300 more accurately.

Referring to FIG. 5, when the pattern P of the sample 300 overlaps with the preset pattern Q which already knows the pattern, an interference pattern (moire pattern) R is generated. When the information on the interference pattern R (for example, the enhanced measurement image) is obtained, information about the sample 300 may be inversely calculated using information of a specific pattern that is known.

In one embodiment, the system 1 may further comprise a patterning unit (not shown) configured to pattern light in a predetermined pattern. The patterning unit may be positioned on an optical path through which light from the light source 110 travels to the sample 300, so that light traveling toward one end surface of the sample 300 may be modulated into a grid pattern.

In one embodiment, the patterning portion may include a transmissive light modulator or a reflective light modulator. The transmissive optical modulator is a modulator to which light is transmitted, and generates various grid patterns and modulates light using electrical signals. The reflective optical modulator is an optical modulator that applies a reflection principle to light transmitted from the light source 110 to form a grid pattern, and may modulate the grid pattern using an electrical signal.

The transmissive optical modulator may include, for example, a Liquid Crystal Spatial Light Modulator (LCSLM) capable of modulating the amplitude or phase of a wavefront by utilizing a liquid crystal. The reflective optical modulator is an optical modulator for attaching and controlling a liquid crystal or a small mirror onto a semiconductor, and may include, for example, a liquid crystal on silicon (LCos), a digital mircromirror device (DMD), or the like. The LCoS panel uses a liquid crystal display (LCD) panel and a reflective chip of DLP (Digital Light Processing) type. The DMD panel is a device that displays images by planting fine mirrors on silicon wafers at regular intervals and controlling the reflection of light through the mirrors.

In addition, the patterning unit may further include additional components (eg, a polarizing beam splitter (PBS), a lens, etc.) for causing the patterned light to travel to the sample 300.

In one embodiment, when the grid pattern modulated light is used by the patterning unit, the image generated based on the optical signal detected by the photodetector 510 is formed in a grid pattern as shown in FIG. 5. The image processor 750 generates an optical image of the sample 300 (ie, an optical image of one side of the sample 300) by using information about the grid pattern that is already known, and adjusts the height of the sample 300. It can be measured.

6A to 6C are diagrams for describing a divided scan operation according to an embodiment of the present invention.

In addition, if the size of the sample 300 is large and there is a portion exceeding the scan area (eg, larger than the optical path range refracted by the lens 130), the entire cross section of the sample 300 is scanned at a time to obtain an actual height. Cannot be measured. Therefore, the height measuring system 1 checks whether the size of the sample 300 is larger than the scan area according to the response of the photodetector 510, and divides and scans the entire cross section of the sample 300 based on the check result. The partial scan operation may be further performed to obtain partial information and to combine the partial information to obtain information about the entire sample 300 to calculate the height.

In one embodiment, the image processor 750 may analyze the optical signal detected in the scan area that is the light reception range of the photodetector 510 to determine whether to perform a divided scan, and perform a divided scan operation.

The sample 300 may move relatively on the optical path before the split scan for the split scan. In one embodiment, the sample stage 310 may be configured to move horizontally and / or vertically for a split scan operation. For example, the sample stage 310 may be a linear stage. In another embodiment, the light source unit 100 and the photodetector 510 may be configured to move horizontally and / or vertically. In this case, the movements of the light source unit 100 and the photo detector 510 correspond to each other.

The height measurement system 1 may further perform a split scan operation when it is determined that a part of the cross section of the sample 300 exceeds the scan area even when the photodetector 510 receives the optical signal.

The image processor 750 generates or receives information on the shape of the sample formed on the basis of the detected optical signal (for example, an image including the shape of the sample 300 having the scan area as a frame) or after receiving the information. The distance from the shape of the sample to the frame of the scan area is calculated to confirm whether the shape of the sample exceeds the scan area.

When the shape of the sample and the distance to each frame of the scan area are 0, the image processor 750 determines that a part of the sample 300 exceeds the scan area. At this time, the moving direction of the sample 300 is determined by the frame having a distance of zero. In addition, size information of the sample on the corresponding frame (eg, the horizontal length of the sample on the horizontal frame and the vertical length of the sample on the vertical frame) can be obtained.

Referring to FIG. 6A, when an image of the scan area A1 is generated, the image processor 750 calculates the shape of the sample 300 and the distance between the frames to determine whether the image is exceeded. Since there is a part where the distance from the left frame to the shape of the sample 300 is calculated as 0, it can be determined that there is an excess part. In addition, specific excess information (ie, horizontal length and / or vertical length) may be calculated such that the excess height is the entire frame height at the right side and the excess length at the bottom is 4/5 of the frame length.

Subsequently, the height measurement system 1 moves the sample 300 to generate an image including the excess portion that is not scanned, and generates an image of the entire sample 300 to increase the height of the entire sample 300. Can be calculated. Here, the image including the excess portion not scanned includes an image including only the excess portion, or an image including the excess portion and a part of the previously scanned portion.

For example, to generate an image of the entirety of the sample 300, the height measurement system 1 may perform a preliminary scan operation that roughly calculates the overall size of the sample 300, based on the approximate size. Compute a split scan order that can accurately generate the entire image of 300. Referring to FIG. 6C, after roughly calculating the overall size of the sample 300, it may be calculated that it is possible to divide the entire cross section of the sample 300 into four divisions. Subsequently, the partial images A2-A5 of the samples 300 included in each scan area are generated according to the divided scan order, and the partial images of the samples 300 for each scan area are combined to prepare the samples 300. By generating the entire image, the height of the entire cross section of the sample 300 may be calculated.

However, the above-described divided scan process and order are exemplary, and the present disclosure is not limited thereto, and the divided scan process and order may be set and performed in various ways within a range for generating an image of the entire sample 300.

In addition, as illustrated in FIG. 6C, the division scan operation may be performed even when the CCD 300 does not respond because the size of the sample 300 is very large and no optical signal is received by the CCD 510. In this case, the height measuring system 1 is irradiated with light from the light source unit 100 but the photodetector 510 does not respond, and the light detector 100 does not respond because no light is irradiated from the light source unit 100. The operation of determining may be further performed. When the height measuring system 1 determines that light is emitted from the light source unit 100 but the photodetector 510 does not respond, for example, after transmitting a command for irradiating light to the light source unit 100, If the photodetector 510 does not respond to the photodetector 510, the photodetector 510 does not respond after a predetermined time for the light source 100 to irradiate light, but is not limited thereto.

If the height measuring system 1 determines that the photodetector 510 does not respond even though light is irradiated, the controller 710 may perform the divided scan operation while moving the sample 300 horizontally and / or vertically. have. For example, as described above, the split scan operation may be performed after the preliminary scan operation of calculating the overall size of the sample 300.

This split scan operation enables the height of the entire sample 300 to be measured even when the size of the sample 300 is quite large (eg, larger than the optical path range refracted by the lens 130).

It will be apparent to those skilled in the art that the system 1 may include other components not described herein. For example, the system 1 may include network interfaces and protocols, input devices for data entry, and other hardware elements required for the operations described herein, including output devices for display, printing, or other data display. It may also include.

The operation by the height measuring system 1 according to the embodiments described above may be recorded at least in part on a computer-readable recording medium embodied as a computer program. Here, the computer may be a device having one or more alternative and special purpose processors, memory, storage, and networking components (either wireless or wired).

In addition, the computer program for implementing the present embodiment is configured in the form of functional programs, instructions, and codes that can be executed in the above-described computer, the functional program, instructions, and code for implementing the present embodiment It will be readily understood by those skilled in the art to which the embodiments belong.

A computer readable recording medium having recorded thereon a program for implementing the operation by the height measuring system 1 according to the embodiments includes all kinds of recording devices in which data that can be read by a computer is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although the present invention described above has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and variations may be made therefrom. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (15)

A light source unit including a light source for irradiating light;
A sample stage on which a sample is placed;
A photodetector including a photodetector configured to receive the light and detect an optical signal;
A patterning portion located on an optical path through which light from the light source proceeds to a sample, wherein the patterning portion is configured to pattern the light in a predetermined pattern; And
A data processing apparatus for calculating a projection area for the sample based on the detected optical signal and determining the height of the projection area as the height of the sample,
And the light received by the photodetector comprises light that has passed around the sample, or light that has passed through the sample incompletely. The method of claim 1, wherein the photodetector,
And a connecting portion configured to vary a height of the projection area by the sample with respect to one cross section of the photodetector. The method of claim 2,
And the data processing device is further configured to determine the maximum value as the height of the sample when the height of at least one projective area is calculated. The method of claim 1,
And the sample stage is located parallel to the optical path between the light source and the photodetector. The data processing apparatus of claim 1, wherein the data processing apparatus comprises:
And set the position of the sample stage as a reference for sample height measurement. A light source unit including a light source for irradiating light;
A sample stage on which a sample is placed;
A light detector for detecting the light signal by receiving the light; And
A data processing apparatus for calculating a projection area for the sample based on the detected optical signal and determining the height of the projection area as the height of the sample,
The data processing device,
Set the position of the sample stage as a reference for sample height measurement,
Further configured to correct the height of the measured sample based on a pre-stored reference table,
The light received by the photodetector includes light passing around the sample, or light incompletely passing through the sample,
And the reference table includes measurement results for reference samples whose height information is known in advance. delete The data processing apparatus of claim 1, wherein the data processing apparatus comprises:
And measure the height of the sample based on the preset pattern and the detected optical signal. The data processing apparatus of claim 1, wherein the data processing apparatus comprises:
And calculate a projection area based on the detected intensity of the optical signal. The method of claim 1, wherein the light source unit,
Further comprising a filter located on the optical path that the light from the light source proceeds to the sample,
And the filter is configured such that the wavelength of the output light is lower than the wavelength of the input light. The method of claim 1,
The light source unit further includes a first lens positioned on an optical path between the light source and the sample stage,
And the photodetector further comprises a second lens positioned on an optical path between the sample stage and the photodetector. The method of claim 1,
And the sample stage is further configured to be movable horizontally or vertically. The data processing apparatus of claim 12, wherein the data processing apparatus comprises:
When the optical signal is detected, by comparing the shape of the sample formed on the basis of the detected optical signal and the scan area of the optical signal receiving range of the photodetector to determine whether the shape of the sample exceeds the scan area,
If it is determined that the shape of the sample exceeds the scan area, the sample is moved to produce a partial image including excess unscanned portions, and
And combining the partial images to obtain an image of the entire cross section of the sample to calculate the height of the sample. The method of claim 13,
The data processing device,
And calculate a distance between the shape of the sample and the frame surrounding the scan area to determine that the shape of the sample exceeds the scan area when the distance is zero. The method of claim 13,
The data processing device,
And further determine to determine that the shape of the sample exceeds the scan area when light is irradiated from the light source and the photodetector is unresponsive.

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