Instant-type white-light interferometer and method for photographing instant white-light interference pattern image of same white light interferometer

Abstract

Disclosed are an instant-type white-light interferometer and a method for photographing an instant white-light interference pattern image of the white light interferometer. The instant-type white-light interferometer obtains the shape of a sample by photographing an interference pattern generated by measurement light reflected from the sample and reflection light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample, extracts a Z value of a zero-crossing point by analyzing a white-light interference pattern, and receives measurement light and reflection light from the scanning assembly maintained at a position corresponding to the Z value to generate and merge a plurality of interference pattern images so as to obtain a surface shape image of the sample, and an image analysis processor corrects the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

Description

Instantaneous white light interferometer and instantaneous white light interference pattern image capturing method of the white light interferometer

[0001] The present invention relates to an instant white light interferometer and a method for capturing an instant white light interference pattern image of the white light interferometer, and more particularly, to an instant white light interferometer capable of continuously capturing the surface of a sample on which a transparent film or the like is disposed, and a method for capturing an instant white light interference pattern image of the white light interferometer.

[0002] In recent fields of nanoscience, semiconductors, nanophysics, nanochemistry, nanomaterials, nanooptics, surface science, medical imaging, biology, biophysics, medical physics, or biomedical optics, there is a growing demand for measuring three-dimensional shape information of samples with three-dimensional nanostructures or micrometer structures.

[0003] White light interferometry, which utilizes the interference phenomenon of white light, has been used to measure the three-dimensional shape information of samples.

[0004] A typical white light interferometer utilizes a beam splitter to separate the white light source and create separate paths for the sample and mirror, respectively. The white light, which is then reflected by the beam splitter onto the sample and mirror, is then recombined and transmitted to a charge-coupled device (CCD) image sensor. The CCD image sensor captures an interference pattern image created by the combined reflected light from the sample and mirror. An image analysis processor analyzes the interference pattern image captured by the CCD image sensor to generate three-dimensional information about the sample's shape.

[0005] At this time, the sample is placed on the stage, and the stage moves along the path axis (typically the z-axis) of the light source by a separate drive assembly to generate a path difference between the sample side and the mirror side. The interference pattern image captured by the CCD image sensor forms different interference pattern images according to the change in the path difference between the sample side and the mirror side, and the image analysis processor generates three-dimensional shape information of the sample based on the interference pattern in which different interference pattern images are accumulated.

[0006] The white light interferometer uses the so-called vertical scanning interferometry, which acquires interference patterns according to changes in the z-axis distance between the stage on which the sample is placed and the optical system such as the beam splitter and CCD image sensor. In vertical scanning interferometry, the z-axis distance between the stage and the optical system is changed at a specific location on the sample to acquire the interference pattern of one frame, and after the sample or the optical system moves a certain distance along the x-axis, the z-axis distance between the stage and the optical system is changed again to acquire the interference pattern of another adjacent frame, and the acquired multiple interference patterns are accumulated or stitched to scan the sample.

[0007] However, the vertical scanning interferometry described above has the problem that it takes a long time to scan the shape of the sample because it requires acquiring an interference pattern by changing the z-axis distance between the stage and the optical system at each specific location, and then acquiring an interference pattern by changing the z-axis distance between the stage and the optical system after the sample or the optical system moves along the x-axis.

[0008] In addition, if a transparent film is placed on the surface of the sample, or the sample has a multilayer structure of different colors, or the sample includes a thick film, there is a problem that an error occurs in the scanning result of the sample because the intensity of light from the transparent film, multilayer structure, or film is added even if the focus is adjusted to the surface of the sample.

[0009] The purpose of the present invention to solve the above-described problems is to provide an instant white light interferometer capable of acquiring the shape of a sample at a higher speed by continuously photographing the surface of a sample after a scanning assembly inclined at a predetermined angle is positioned at a zero-crossing point for a sample having a transparent film or the like disposed on the surface, and a method for capturing an instant white light interference pattern image of the white light interferometer by measuring the brightness of the sample itself and correcting it to obtain a corrected surface shape image of the sample.

[0010] In order to achieve the above-described object, an instant white light interferometer according to one embodiment of the present invention is an instant white light interferometer (WLI) that acquires the shape of a sample by photographing an interference pattern generated by measurement light reflected from a sample and reflected light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample, and the white light interferometer comprises: a light source providing white light, a stage on which a sample is placed, a mirror having a reflective surface, a beam splitter that divides the path of the white light provided from the light source into the sample side and the mirror side, a stage moving assembly that moves the stage in the X-axis direction in which the sample is scanned, an optical moving assembly that moves the scanning assembly in the Z-axis direction toward the sample, a CCD image sensor (Charge Coupled Device image sensor) that receives the measurement light and the reflected light and photographs an interference pattern generated by the measurement light and the reflected light, and an image analysis processor that generates a white light interference fringe signal (WLI Fringe) based on the interference pattern, and the image analysis processor comprises: By analyzing a white light interference pattern signal, a Z value of a zero-crossing point where the intensity of light changes abruptly is extracted, and the optical movement assembly moves the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value, and the stage movement assembly moves the stage in the x-axis direction after the scanning assembly moves to the position corresponding to the Z value, and the CCD image sensor receives the measurement light and the reflected light from the scanning assembly, which is maintained at the position corresponding to the Z value, while the stage movement assembly moves the stage, to generate a plurality of interference pattern images.The image analysis processor acquires a surface shape image of the sample by merging the plurality of interference pattern images, and the image analysis processor corrects the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

[0011] The image analysis processor, when correcting the brightness of the surface shape image of the sample, measures the brightness level of the sample and corrects the brightness of the surface shape image of the sample by removing the brightness level of the sample from the surface shape image of the sample.

[0012] The stage movement assembly moves the stage in the x-axis direction in which the sample is scanned, and then moves the stage again in the -x-axis direction, and the optical movement assembly maintains the scanning assembly at a position 10 μm to 100 μm higher than the Z value with respect to the surface of the sample when the stage is moved in the x-axis direction, so that the CCD image sensor measures the brightness of the sample, and maintains the scanning assembly at a position corresponding to the Z value with respect to the surface of the sample when the stage is moved in the -X-axis direction, so that the CCD image sensor generates an interference pattern image of the sample.

[0013] The CCD image sensor includes a first CCD image sensor for measuring the brightness of the sample and a second CCD image sensor for acquiring an interference pattern image of the sample surface, and the beam splitter includes a beam splitter having more light transmission than light reflection, and the beam splitter divides the measurement light reflected from the sample and the reflected light reflected from the mirror and transmits the splitted measurement light to the first CCD image sensor and the second CCD image sensor, and the beam splitter transmits and reflects the measurement light reflected from the sample, and the measurement light transmitted from the beam splitter is transmitted to the first CCD image sensor, and the measurement light reflected from the beam splitter is transmitted to the second CCD image sensor, and the beam splitter transmits and reflects the reflected light reflected from the mirror, and the reflected light transmitted from the beam splitter is transmitted to the second CCD image sensor, and the reflected light reflected from the beam splitter is transmitted to the first CCD image sensor, so that the first CCD image sensor The brightness of the sample is measured by receiving the measurement light transmitted from the beam splitter, which is brighter than the reflected light reflected from the splitter.

[0014] The beam splitter is a beam splitter having a light transmittance and reflection ratio of 90:10, and 81% of the white light transmitted through the beam splitter is received by the first CCD image sensor, and 1% of the white light reflected from the beam splitter is received by the first CCD image sensor, so that the first CCD image sensor measures the brightness of the sample, and 9% of the white light reflected from the beam splitter is received by the second CCD image sensor, and 9% of the white light transmitted through the beam splitter is received by the second CCD image sensor, so that the second CCD image sensor acquires an interference pattern image of the surface of the sample.

[0015] In order to achieve the above-described object, an instant white light interferometer according to one embodiment of the present invention is an instant white light interferometer (WLI) that acquires the shape of a sample by photographing an interference pattern generated by measurement light reflected from a sample and reflected light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample, and the white light interferometer includes a light source that provides white light, a stage on which a sample is placed, a mirror having a reflective surface, a beam splitter that divides the path of the white light provided from the light source into a sample side and a mirror side, an optical movement assembly that moves the scanning assembly in an X-axis direction in which the sample is scanned and a Z-axis direction toward the sample, a CCD image sensor (Charge Coupled Device image sensor) that receives the measurement light and the reflected light and photographs an interference pattern generated by the measurement light and the reflected light, and an image analysis processor that generates a white light interference pattern signal (WLI Fringe) based on the interference pattern, and the image analysis processor analyzes the white light interference pattern signal to determine the light The Z value of the zero-crossing point where the intensity changes abruptly is extracted, and the optical movement assembly moves the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value, and then moves the scanning assembly in the x-axis direction while the scanning assembly is maintained at the position corresponding to the Z value with respect to the surface of the sample, and the CCD image sensor receives the measurement light and the reflected light from the scanning assembly while the optical movement assembly moves the scanning assembly in the x-axis direction to generate a plurality of interference pattern images, and the image analysis processor merges the plurality of interference pattern images to acquire a surface shape image of the sample.The image analysis processor corrects the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

[0016] In order to achieve the above-described object, an instant white light interference pattern image capturing method of a white light interferometer according to an embodiment of the present invention comprises: a step of generating a white light interference pattern signal based on an interference pattern generated by measurement light reflected from a sample and reflected light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample; a step of an image analysis processor analyzing the white light interference pattern signal to extract a Z value of a zero-crossing point where the intensity of light changes abruptly; a step of an optical movement assembly moving the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value; a step of a stage movement assembly moving a stage on which the sample is placed in the x-axis direction; a step of a CCD image sensor receiving the measurement light and the reflected light from the scanning assembly to generate a plurality of interference pattern images; and a step of the image analysis processor merging the plurality of interference pattern images to acquire a surface shape image of the sample, wherein the method comprises a step of the image analysis processor correcting the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample. Includes more.

[0017] The step of moving the stage on which the sample is placed in the x-axis direction of the stage moving assembly further includes a step of measuring the brightness level of the sample, and the step of correcting the brightness of the surface shape image of the sample includes a step of correcting the brightness of the surface shape image of the sample by removing the brightness level of the sample from the surface shape image of the sample.

[0018] The step of measuring the brightness of the sample includes a step of the stage movement assembly moving the stage in the x-axis direction in which the sample is scanned, and in the step of the stage movement assembly moving the stage in the x-axis direction in which the sample is scanned, the optical movement assembly maintains the scanning assembly at a position 10 μm to 100 μm higher than the Z value with respect to the surface of the sample when the stage is moved in the x-axis direction, so that the CCD image sensor measures the brightness of the sample.

[0019] The step of measuring the brightness of the sample includes a step of splitting the measurement light reflected from the sample and the reflected light reflected from the mirror by a beam splitter having more light transmission than light reflection, and transmitting the split light to a first CCD image sensor for measuring the brightness of the sample and a second CCD image sensor for acquiring an interference pattern image of the surface of the sample, and in the transmitting step, the beam splitter transmits and reflects the measurement light reflected from the sample, the measurement light transmitted from the beam splitter is transmitted to the first CCD image sensor, and the measurement light reflected from the beam splitter is transmitted to the second CCD image sensor, and the beam splitter transmits and reflects the reflected light reflected from the mirror, the reflected light transmitted from the beam splitter is transmitted to the second CCD image sensor, and the reflected light reflected from the beam splitter is transmitted to the first CCD image sensor, so that the first CCD image sensor receives the measurement light transmitted from the beam splitter, which is brighter than the reflected light reflected from the beam splitter. Receive and measure the brightness of the sample.

[0020] According to the instant white light interferometer of the present invention and the instant white light interference pattern image capturing method of the white light interferometer, a scanning assembly inclined at a predetermined angle is positioned at a zero-crossing point for a sample having a transparent film or the like disposed on the surface, and then the surface of the sample is continuously captured to acquire the shape of the sample at a further improved speed, and a corrected surface shape image of the sample can be acquired through correction that measures the brightness of the sample itself and removes it.

[0021] FIG. 1 is a drawing showing one embodiment of an instantaneous white light interferometer according to the present invention.

[0022] FIG. 2 is a drawing showing another embodiment of an instantaneous white light interferometer according to the present invention.

[0023] FIG. 3 is a drawing showing a sample surface shape image acquired from a conventional white light interferometer and a sample surface shape image acquired from a white light interferometer according to the present invention.

[0024] FIG. 4 is a drawing for explaining a negative zero-crossing point according to the present invention.

[0025] FIG. 5 is a drawing for explaining the location where the Z value of the zero-crossing point according to the present invention exists.

[0026] FIG. 6 is a drawing for explaining the degree to which the scanning assembly according to the present invention is tilted with respect to a sample.

[0027] Figure 7 is a drawing showing the saturation phenomenon of WLI Intensity according to the degree of inclination of the scanning assembly.

[0028] Figure 8 is a drawing showing a conventional white light interferometer and a white light interferometer according to the present invention.

[0029] FIG. 9 is a drawing showing a scanning assembly according to the present invention sliding on the surface of a sample.

[0030] Figure 10 is a drawing showing the appearance of a sample including a transparent film.

[0031] FIG. 11 is a drawing showing a scanning assembly according to the present invention moving unidirectionally across the surface of a sample to measure the surface brightness of the sample.

[0032] Figures 12 and 13 are flowcharts of a method for capturing an instant white light interference pattern image using a white light interferometer according to the present invention.

[0033] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components are given the same reference numerals, even if they appear in different drawings.

[0034] And when describing an embodiment of the present invention, if it is determined that a specific description of a related known configuration or function hinders understanding of the embodiment of the present invention, the detailed description is omitted.

[0035] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms.

[0036] In this specification, the singular includes the plural unless specifically stated otherwise. The terms “comprises” and / or “comprising” as used herein do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0037] Hereinafter, the present invention will be described in more detail with reference to the attached drawings.

[0038]

[0039] FIG. 1 is a drawing showing one embodiment of an instant-type white light interferometer (100) according to the present invention, and FIG. 2 is a drawing showing another embodiment of an instant-type white light interferometer (100) according to the present invention. Specifically, FIG. 1 shows one embodiment of an instant-type white light interferometer (100) according to the present invention as a Michelson-type interferometer, and FIG. 2 shows another embodiment of an instant-type white light interferometer (100) according to the present invention as a Mirau-type interferometer.

[0040] The instantaneous white light interferometer (100) according to the present invention (hereinafter referred to as the 'white light interferometer (100)') can be applied as a Michelson type interferometer and a Mirau type interferometer depending on the arrangement of each component, as shown in FIGS. 1 and 2. Alternatively, it can be applied as a Linnik type interferometer as shown in (a) of FIG. 11.

[0041] A white light interferometer (WLI) according to the present invention includes a light source (10), a beam splitter (20), a mirror (30), a stage (40), a stage movement assembly (50), a CCD image sensor (60), and an image analysis processor (70). In addition, the white light interferometer (100) according to the present invention may further include an optical movement assembly (81) that moves a scanning assembly (80). Here, the scanning assembly (80) includes a light source (10), a beam splitter (20), a mirror (30), and a CCD image sensor (60). The optical movement assembly (81) includes a z-scanner (82, z-scanner) for tracking and scanning a height and position of the scanning assembly (80) with respect to a sample (41), and a z-servo (83, z-servo) for controlling the height and position of the scanning assembly (80) with respect to the sample (41). The optical movement assembly (81) can move the scanning assembly (80) in the z-axis direction toward the sample (41). The optical movement assembly (81) can change the path length of white light toward the sample (41) by moving the scanning assembly (80) in the z-axis direction. As the optical movement assembly (81) moves the scanning assembly (80) in the z-axis direction, a path difference between the measurement light and the reflected light is generated.

[0042] The white light interferometer (100) according to the present invention may further include separate lenses (not shown) for focusing and controlling the path of white light, measurement light, and reflected light on the light source (10) side, the sample (41) side, the mirror (30) side, and the CCD image sensor (60) side, with the beam splitter (20) as the center.

[0043] A white light interferometer (100) according to the present invention acquires the shape of a sample (41) by photographing an interference pattern generated by measurement light reflected from a sample (41) and reflected light reflected from a mirror (30) through a scanning assembly (80) tilted at a predetermined angle with respect to the sample (41). A white light interferometer (100) according to the present invention continuously photographs an interference pattern generated by measurement light reflected from a sample (41) and reflected light reflected from a mirror (30) through a scanning assembly (80) tilted at a predetermined angle with respect to the sample (41), thereby analyzing shape information of a sample (41), specifically, the surface height and step difference of the sample (41).

[0044] The scanning assembly (80) can be tilted at a predetermined angle with respect to the sample (41) by the optical movement assembly (81). Alternatively, the stage (40) can be tilted at a predetermined angle by the stage movement assembly (50). The optical movement assembly (81) provides z-axis movement of the scanning assembly (80). The stage movement assembly (50) provides x-axis movement of the stage (40). When the stage movement assembly (50) moves the stage (40) in the x-axis direction, the optical movement assembly (81) can also tilt only the lens disposed between the beam splitter (20) and the sample (41) side at a predetermined angle.

[0045] The scanning assembly (80) can be tilted at a predetermined angle with respect to the sample (41), or the stage (40) can be tilted at a predetermined angle with respect to the scanning assembly (80). At this time, the direction in which the scanning assembly (80) or the stage (40) is tilted can be tilted in the x-axis direction as shown in FIG. 2, but is not limited thereto, and can also be tilted in the y-axis direction, or can be tilted on the xy plane.

[0046]

[0047] The light source (10) generates white light. A halogen lamp or a white LED that generates white light can be applied as the light source (10). The light source (10) provides white light to a beam splitter (20), and the beam splitter (20) splits the white light provided from the light source (10) and provides it to a sample (41) and a mirror (30).

[0048] A sample (41) is placed on the upper surface of the stage (40). The sample (41) is a measurement target for which surface information is to be measured. The sample (41) may be a nanostructure such as a semiconductor element.

[0049] The stage movement assembly (50) moves the stage (40). The stage movement assembly (50) moves the stage (40) in the X-axis direction in which the sample (41) is scanned or to be scanned, while maintaining a predetermined angle between the path of white light provided from the beam splitter (20) toward the sample (41) and the sample (41) side.

[0050] The mirror (30) has a reflective surface on one side facing the beam splitter (20).

[0051] The beam splitter (20) splits the path of white light provided from the light source (10) into the sample (41) side and the mirror (30) side. The beam splitter (20) provides some of the white light provided from the light source (10) to the stage (40) side.

[0052] The beam splitter (20) provides the remainder of the white light provided from the light source (10) to the mirror (30). The white light provided to the mirror (30) is reflected and transmitted back to the beam splitter (20). The beam splitter (20) changes the path of the reflected light so that the reflected light reflected from the mirror (30) is transmitted to the CCD image sensor (60).

[0053] The beam splitter (20) splits white light into the sample (41) side and the reflective surface side of the mirror (30). The measurement light reflected from the sample (41) and the reflected light reflected from the mirror (30) are transmitted to the CCD image sensor (60) by the beam splitter (20). The CCD image sensor (60) receives an interference pattern that occurs due to a change in the path difference between the measurement light reflected from the sample (41) and the reflected light reflected from the mirror (30).

[0054] The beam splitter (20) changes the path of the white light so that some of the white light provided from the light source (10) is transmitted to the stage (40) side and the sample (41) side. The beam splitter (20) changes the path of the white light so that the path of the white light provided to the sample (41) side has a predetermined angle with the sample (41) side. The white light is irradiated to the sample (41) so as to have a predetermined angle. Therefore, the optical axis irradiated to the sample (41) is tilted at a predetermined angle.

[0055] The beam splitter (20) can be tilted to maintain a predetermined angle with the surface of the sample (41). The white light transmitted toward the sample (41) is reflected back to the beam splitter (20) as measurement light, and is transmitted to the CCD image sensor (60) through the beam splitter (20).

[0056] A CCD image sensor (60, Charge Coupled Device image sensor) receives measurement light reflected from a sample (41) from a beam splitter (20) and reflected light reflected from a mirror (30). The CCD image sensor (60) receives measurement light and reflected light from the beam splitter (20) while the stage movement assembly (50) moves the stage (40) in the x-axis direction or while the optical movement assembly (81) moves the scanning assembly (80) in the x-axis direction.

[0057] The CCD image sensor (60) receives measurement light and reflected light from the sample (41) when the stage (40) moves in the x-axis direction or the scanning assembly (80) moves in the x-axis direction, and photographs an interference pattern generated by the measurement light and reflected light. At this time, the scanning assembly (80) and the sample (41) are tilted at a predetermined angle to each other, so the optical axis irradiated to the sample (41) is tilted at a predetermined angle.

[0058] The CCD image sensor (60) continuously captures interference patterns while the stage (40) moves in the x-axis direction or the scanning assembly (80) moves in the x-axis direction to generate multiple interference pattern images.

[0059] The CCD image sensor (60) continuously captures interference patterns of pixels generated by measurement light and reflected light while the stage (40) moves in the x-axis direction or the scanning assembly (80) moves in the x-axis direction. The CCD image sensor (60) continuously captures interference patterns to generate multiple interference pattern images. Here, a pixel means a unit pixel included on the XY plane of the interference pattern image.

[0060] The CCD image sensor (60) transmits multiple interference pattern images captured continuously to the image analysis processor (70).

[0061] The image analysis processor (70) merges (flattens) multiple interference pattern images received from the CCD image sensor (60) to generate a white light interference pattern signal (WLI fringe signal). The image analysis processor (70) analyzes the generated white light interference pattern signal to derive the surface shape of the sample (41), specifically, the height and step of the sample (41). Since the white light interferometer (100) measures the surface shape using light reflected from the sample (41), it has the advantage of being able to measure quickly without damaging the sample (41).

[0062]

[0063] The image analysis processor (70) according to the present invention analyzes the generated white light interference pattern signal to extract the Z value of the zero-crossing point where the light intensity changes abruptly (see (d) of FIG. 4). The optical movement assembly (81) moves the scanning assembly (80) from the surface of the sample (41) to a position corresponding to the Z value based on the Z value extracted by the image analysis processor (70). The stage movement assembly (50) moves the stage (40) in the x-axis direction after the scanning assembly (80) moves to the position corresponding to the Z value. The CCD image sensor (60) receives the measurement light and the reflected light from the scanning assembly (80) maintained at the position corresponding to the Z value while the stage movement assembly (50) moves the stage (40), thereby generating a plurality of interference pattern images, and the image analysis processor (70) merges the generated plurality of interference pattern images to acquire a surface shape image of the sample (41).

[0064]

[0065] In summary, a white light interferometer (100) according to one embodiment of the present invention tilts a scanning assembly (80) to have a predetermined angle with respect to a sample (41), moves a stage (40) in the x-axis direction while being spaced apart by the Z value of a zero-crossing point between the scanning assembly (80) and the sample (41), and continuously captures interference patterns generated by measurement light of white light irradiated on the sample (41) and reflected light reflected from a mirror (30). A plurality of interference pattern images generated by continuously capturing are merged into a surface shape image of the sample (41).

[0066] In this specification, the distance between the scanning assembly (80) and the sample (41) means the distance between the WLI lens in the scanning assembly (80) and the surface of the sample (41). For example, when the scanning assembly (80) moves from the surface of the sample (41) to a position corresponding to the Z value, it can be understood that the distance between the WLI lens in the scanning assembly (80) and the surface of the sample (41) corresponds to the Z value. At this time, the WLI lens in the scanning assembly (80) may mean a lens placed between the beam splitter (20) and the sample (41) side.

[0067]

[0068] FIG. 3 is a drawing showing a surface shape image of a sample (41) acquired from a conventional white light interferometer and a surface shape image of a sample (41) acquired from a white light interferometer (100) according to the present invention. Specifically, (a) of FIG. 3 is a surface shape image of a sample (41) acquired from a conventional white light interferometer, and (b) of FIG. 3 is a surface shape image of a sample (41) acquired from a white light interferometer (100) according to the present invention.

[0069] Referring to FIG. 3, the conventional white light interferometer, as described above, acquires an interference pattern according to the change in the z-axis distance between the stage (40) on which the sample (41) is placed and the optical system such as the beam splitter (20) and the CCD image sensor (60). The conventional white light interferometer acquires an interference pattern of one frame by changing the z-axis distance between the stage (40) and the optical system at a specific position of the sample (41), and then, after the sample (41) or the optical system moves a certain distance in the x-axis, changes the z-axis distance between the stage (40) and the optical system again to acquire an interference pattern of another adjacent frame, and scans the sample (41) by accumulating or stitching a plurality of acquired interference patterns, thereby measuring tens to hundreds of frames at a specific position, and then measuring tens to hundreds of frames again at another specific position, so that there was a problem that the time required for scanning the shape of the sample (41) was long.

[0070] However, the white light interferometer (100) according to the present invention acquires only one image in one frame after positioning the scanning assembly (80) at a position corresponding to the Z value of the zero-crossing point. In addition, the white light interferometer (100) according to the present invention acquires only one image in each frame by moving the stage (40) in the x direction while maintaining the scanning assembly (80) at a position corresponding to the Z value, and then merges the respective images to acquire an image of the surface shape of the sample (41). The image of the surface shape of the sample (41) acquired by the white light interferometer (100) according to the present invention (Fig. 3 (b), WLI Intensity Image) and the image of the surface shape of the sample (41) acquired by the conventional white light interferometer (Fig. 3 (a), WLI Height Image) are very similar to each other, and therefore, the image of the surface shape of the sample (41) can be acquired faster than the conventional white light interferometer.

[0071] The white light interferometer (100) according to the present invention simplifies WLI measurement while maintaining its sensitivity. In order to maintain the sensitivity of WLI measurement, the white light interferometer (100) according to the present invention acquires only one image at the point where the intensity of light changes most rapidly depending on the Z value.

[0072] In addition, the white light interferometer (100) according to the present invention measures only the section where the height and WLI INTENSITY are linear in order to simplify calculation of the height (step) of the surface shape of the sample (41), and at this time, the Z value, which is the point where the intensity of light changes most rapidly, exists within the section (±30 nm) where the white light interference pattern signal and the height of the surface of the sample (41) are linearly coincident with each other.

[0073]

[0074] In a white light interference pattern signal, the zero crossing point where the light intensity changes most rapidly is located near the center where the light intensity is the greatest. When the center is enlarged, it is as shown in the graph of Fig. 4 (d). When the scanning assembly (80) is positioned at a plurality of positions corresponding to the Z values ​​from the center of the graph of Fig. 4 (d) and the interference pattern (WLI Intensity Image) according to the measured light and the reflected light is examined, the interference pattern changes most sensitively at a specific point (Negative Zero Crossing, Positive Zero Crossing). In the peak (Fringe Peak) part of the interference pattern signal, the pattern is not distinguishable or rather inverted. The point where the interference pattern changes most sensitively is referred to as the zero-crossing point in this specification. The white light interferometer (100) according to the present invention captures an interference pattern image by positioning the scanning assembly (80) at a position corresponding to the Z value of the zero-crossing point.

[0075]

[0076] FIG. 4 is a drawing for explaining a negative zero-crossing point according to the present invention. Specifically, (a) of FIG. 4 is an interference pattern image acquired using a conventional white light interferometer, (b) of FIG. 4 is an interference pattern image acquired after the scanning assembly (80) is positioned at the Z value of the negative zero-crossing point in the white light interferometer (100) according to the present invention, (c) of FIG. 4 is an interference pattern image acquired after the scanning assembly (80) is positioned at the Z value of the positive zero-crossing point in the white light interferometer (100) according to the present invention, and (d) of FIG. 4 is an image magnified near the center of a white light interference pattern signal (WLI Fringe) generated by an image analysis processor (70).

[0077] As for the zero-crossing points where the intensity of light in the white light interference pattern signal changes most rapidly, there are negative zero-crossing points and positive zero-crossing points, as shown in (d) of Fig. 4.

[0078] Figure 4 (b) is an interference pattern image acquired from a scanning assembly (80) located at a negative zero-crossing point, and Figure 4 (c) is an interference pattern image acquired from a scanning assembly (80) located at a positive zero-crossing point.

[0079] Comparing Fig. 4 (b) and Fig. 4 (c) with Fig. 4 (a), it can be seen that Fig. 4 (b) has the same interference pattern as Fig. 4 (a), and Fig. 4 (c) has the opposite interference pattern as Fig. 4 (a).

[0080] Accordingly, in order to simplify calculation, the zero-crossing point according to the present invention can be applied by selecting a negative zero-crossing point among the negative zero-crossing point and the positive zero-crossing point when applying the zero-crossing point of the Z value.

[0081]

[0082] FIG. 5 is a drawing for explaining the position where the Z value of the zero-crossing point exists according to the present invention. Specifically, (a) of FIG. 5 is an interference pattern image acquired after the scanning assembly (80) is positioned at the Z value of the negative zero-crossing point in the white light interferometer (100) according to the present invention, (b) of FIG. 5 is an interference pattern image acquired using a conventional white light interferometer, and (c) of FIG. 5 is an image showing the interference pattern signals of (a) and (b) of FIG. 5.

[0083] Referring to (c) of FIG. 5, it can be seen that the interference pattern signal (Height) acquired from the interference pattern image acquired using a conventional white light interferometer and the interference pattern signal (Linearized Height) acquired from the interference pattern image acquired after the scanning assembly (80) is positioned at the Z value of the negative zero-crossing point in the white light interferometer (100) according to the present invention are linear within a certain range.

[0084] That is, there is a section (Valid Region) in which the interference pattern image (Linearized Height) acquired after the scanning assembly (80) is positioned at the Z value of the negative zero-crossing point linearly matches the surface step (Height) of the actual sample (41), and at this time, the Z value exists within that section. That is, the Z value of the zero-crossing point exists within the section in which the white light interference pattern signal and the height of the surface of the sample (41) linearly match each other, and for example, the range of the Z value of that section is ±30 nm, or 60 nm in total.

[0085]

[0086] Therefore, since the Z value of the zero-crossing point exists within the ±30 nm range, the scanning assembly (80) must be positioned within the ±30 nm range with respect to the sample (41). As described above, the optical movement assembly (81) moves the scanning assembly (80) to a position corresponding to the Z value of the zero-crossing point with respect to the sample (41). After the scanning assembly (80) is positioned at the Z value of the zero-crossing point, the stage (40) is moved in the x-axis direction by the stage movement assembly (50).

[0087] At this time, when the height of the surface of the sample (41) changes due to a step existing in the sample (41), the Z scanner (82) detects the height of the surface of the sample (41) changed by the step, and based on the detected height of the surface of the sample (41), the height and position of the scanning assembly (80) with respect to the sample (41) are controlled by the Z servo (83).

[0088] That is, the optical movement assembly (81) changes the position of the scanning assembly (80) so that the distance between the scanning assembly (80) and the surface of the sample (41) is maintained at the Z value of the zero-crossing point when the stage (40) is moved in the x-axis direction, and thus the scanning assembly (80) is Z-tracked to be positioned within a range of ±30 nm with respect to the sample (41).

[0089]

[0090] As shown in (a) of Fig. 5, in a white light interferometer (100) according to the present invention, the position of the scanning assembly (80) or the step of the surface of the sample (41) can be calculated based on the interference pattern image acquired after the scanning assembly (80) is positioned at the Z value of the negative zero-crossing point, based on the following <Formula 1>.

[0091]

[0092]

[0093] <Formula 1>

[0094] Here, △h is the step of the sample (41), I is the light intensity of a pixel in the image captured at the zero-crossing point, I0 is the reference light intensity (Reference Inetnsity), and s is a constant.

[0095]

[0096] Based on <Formula 1>, the step of the sample (41) corresponding to a specific pixel can be calculated based on the light intensity of the specific pixel. I0 is the reference light intensity, and in one embodiment, it can be 'I0=140'. s is a constant, and s is divided to change the step of the sample (41) to nm. In one embodiment, s can be 1.75.

[0097] If <Formula 1> is changed according to the above conditions, it can be expressed as <Formula 2> below.

[0098]

[0099]

[0100] <Formula 2>

[0101] Here, △h is the step of the sample (41), and I is the light intensity of the pixel in the image captured at the zero-crossing point.

[0102]

[0103] FIG. 6 is a drawing for explaining the degree to which the scanning assembly (80) according to the present invention is tilted with respect to the sample (41). Specifically, FIG. 6 (a) and FIG. 6 (b) are drawings showing interference patterns on the surface of the sample (41) acquired by a conventional horizontal scanning interferometer, and FIG. 6 (c) is a drawing showing interference patterns on the surface of the sample (41) acquired by a white light interferometer (100) according to the present invention. FIG. 7 is a drawing showing a saturation phenomenon of WLI Intensity according to the degree of tilt of the scanning assembly (80).

[0104] The scanning assembly (80) according to the present invention, as described above, maintains a state of being tilted at a predetermined angle with respect to the sample (41).

[0105] In conventional white light interferometers, there exists a horizontal scanning interferometry (Lateral Scanning WLI) to solve the problems of the aforementioned vertical scanning interferometry. The conventional horizontal scanning interferometry scans the surface of the sample (41) laterally with respect to the sample (41) with an optical system, and acquires the shape of the surface of the sample (41) based on the change in the phase difference of the interference pattern formed on the surface of the sample (41). The conventional horizontal scanning interferometry analyzes the interference pattern formed on the surface of the sample (41) to acquire the shape of the surface of the sample (41), thereby tilting the optical system to an extent where the interference pattern can be easily generated on the surface of the sample (41), for example, as shown in (a) of FIG. 6, it has a tilt level of z tilt 260 nm or z tilt 85 nm as shown in (b) of FIG. 6.

[0106] However, the scanning assembly (80) according to the present invention requires a tilt level of z tilt ±30 nm. The reason why the scanning assembly (80) according to the present invention requires a tilt level of z tilt ±30 nm is because the intensity must appear linearly in all areas within the image.

[0107] Therefore, as illustrated in (c) of FIG. 6, the scanning assembly (80) according to the present invention is tilted at a predetermined angle so that the entire interference pattern image is included in the same interference pattern or so that no interference pattern appears. That is, the scanning assembly (80) is tilted at a predetermined angle so that the entire interference pattern image is included in either the dark or bright portion of the interference pattern.

[0108] In conventional horizontal scanning interferometry, it works well even if the interference pattern within the image has a tilt of about 1 (235 nm), but in the interferometry based on the Z value of the zero-crossing according to the present invention, the entire image must be located within the linear regime (±30 nm).

[0109]

[0110] Referring to (a) and (b) of FIG. 7, it can be seen that in the conventional horizontal scanning interferometry, the texture of the surface of the sample (41) is not measured due to the occurrence of saturation of the intensity within a specific pixel as a result of the occurrence of an interference pattern within the image. On the other hand, referring to (c) of FIG. 7, it can be seen that in the scanning assembly (80) according to the present invention, the fine texture is measured in the entire image as the entire interference pattern image is included in the same interference pattern or tilted at a predetermined angle so that no interference pattern appears.

[0111] According to the zero-crossing interferometry of the present invention, if the tilt exceeds the linear region (±30 nm), the texture (~1 nm) of the surface of the sample (41) is not clearly measured. However, if the z tilt is reduced to within ±30 nm, fine texture can be measured in all image areas similar to the WLI height image as shown in (d) of Fig. 7.

[0112]

[0113] Figure 8 is a drawing showing a conventional white light interferometer and a white light interferometer according to the present invention.

[0114] As shown in (a) of FIG. 8, the conventional white light interferometry is a vertical scanning interferometry, in which the z-axis distance between the stage (40) and the optical system is changed at a specific location of the sample (41) to acquire an interference pattern of one frame, and after the sample (41) or the optical system moves a certain distance along the x-axis, the z-axis distance between the stage (40) and the optical system is changed again to acquire an interference pattern of another adjacent frame, and then the acquired multiple interference patterns are accumulated or stitched to scan the sample (41).

[0115] On the other hand, as shown in (b) and (c) of FIG. 8, the white light interferometer (100) according to the present invention acquires surface shape information of the sample (41) by sliding the surface of the sample (41) while the scanning assembly (80) is tilted at a predetermined angle.

[0116] As shown in (c) of FIG. 8, the white light interferometer (100) according to the present invention allows the stage (40) to move in the x direction while the scanning assembly (80) maintains the Z value of the zero-crossing point.

[0117] As shown in (b) of FIG. 8, the white light interferometer (100) according to the present invention can acquire surface shape information of a sample (41) while the scanning assembly (80) moves in the x direction while maintaining the Z value of the zero-crossing point.

[0118] The optical movement assembly (81) moves the scanning assembly (80) in the z-axis direction toward the sample (41) and maintains it at the Z value of the zero-crossing point. The optical movement assembly (81) can move the scanning assembly (80) in the x-axis along which the sample (41) is scanned while maintaining the scanning assembly (80) at the Z value of the zero-crossing point.

[0119] Thereafter, the CCD image sensor (60) receives measurement light and reflected light from the scanning assembly (80) while the optical movement assembly (81) moves the scanning assembly (80) in the X-axis direction, thereby generating a plurality of interference pattern images.

[0120]

[0121] Additionally, the distance between the stage (40) and the scanning assembly (80) may be adjusted so that the stage (40) moves in the z direction without moving the scanning assembly (80) so that the scanning assembly (80) is positioned at the Z value of the zero-crossing point. After the stage (40) moves in the z direction, the stage (40) may move in the x direction, or the scanning assembly (80) may move in the x direction.

[0122]

[0123] Figure 9 is a drawing showing a scanning assembly (80) according to the present invention sliding on the surface of a sample (41).

[0124] Figure 9 (a) is a drawing showing a scanning assembly (80) acquiring surface information of a sample (41) while sliding on the surface of the sample (41).

[0125] As described above, the scanning assembly (80) scans the surface of the sample (41) while maintaining a constant zero-crossing point Z value according to the step of the sample (41).

[0126] However, if a transparent film is placed on the surface of the sample (41), or the sample (41) has a multilayer structure of different colors, or the sample (41) includes a thick film, the image analysis processor (70) corrects the brightness of the surface shape image of the sample (41) and then acquires the surface shape image of the sample (41).

[0127]

[0128] Figure 10 is a drawing showing the appearance of a sample (41) including a transparent film.

[0129] Referring to Fig. 10, when the scanning assembly (80) scans the surface of the sample (41), if the sample (41) includes a transparent film, even if the focus is adjusted to the surface of the sample (41), the intensity of light from the transparent film is added. Therefore, the image analysis processor (70) acquires a surface shape image of the sample (41) that has been corrected by measuring the brightness of the sample (41) itself and removing it to leave only the components related to the surface of the sample (41).

[0130] The image analysis processor (70) flattens multiple interference pattern images to obtain a surface shape image of the sample (41), and then appropriately increases the contrast in the obtained surface shape image of the sample (41) to similarly correct the WLI Intensity Image and the WLI Height Image.

[0131]

[0132] When correcting the brightness of the surface shape image of the sample (41), the image analysis processor (70) measures the brightness of the sample (41) and removes the measured brightness of the sample (41) from the surface shape image of the sample (41) to correct the brightness of the surface shape image of the sample (41).

[0133] When correcting the brightness of the surface shape image of the sample (41) of the image analysis processor (70), two embodiments of the Double Path method and the Single Path method are included as shown in (b) and (c) of FIG. 9.

[0134]

[0135] First, as an example of correction of the brightness of the surface shape image of the sample (41) by the image analysis processor (70), as shown in (b) of FIG. 9, the scanning assembly (80) reciprocates the surface of the sample (41) (Double Path) to correct the brightness of the surface shape image of the sample (41).

[0136] The scanning assembly (80) first measures the brightness of the sample (41) itself by moving the scanning assembly (80) or the stage (40) in the x direction, after which the scanning assembly (80) or the stage (40) moves in the -x direction and returns to the position at the Z value, which is the zero-crossing point, to scan the surface of the sample (41). Alternatively, the scanning assembly (80) may be positioned at the Z value, which is the zero-crossing point, while the scanning assembly (80) or the stage (40) moves in the x direction to scan the surface of the sample (41), and then moves in the -x direction again to return to the position at the Z value, which is the zero-crossing point, to measure the brightness of the sample (41) itself. The image analysis processor (70) can obtain a surface shape image of the sample (41) that has been corrected by removing the brightness of the sample (41) itself from the surface image of the scanned sample (41).

[0137] In detail, the stage movement assembly (50) moves the stage (40) in the x-axis direction in which the sample (41) is scanned, and then moves the stage (40) in the -x-axis direction again. Alternatively, the scanning assembly (80) may be moved in the x-axis direction and then moved in the -x-axis direction again by the optical movement assembly (81). The optical movement assembly (81) maintains the scanning assembly (80) at a position that is 10 μm to 100 μm higher than the Z value, which is a zero-crossing point, with respect to the surface of the sample (41) when the stage (40) is moved in the x-axis direction, so that the CCD image sensor (60) measures the brightness of the sample (41), and maintains the scanning assembly (80) at a position corresponding to the Z value with respect to the surface of the sample (41) when the stage (40) is moved in the -X-axis direction, so that the CCD image sensor (60) generates an interference pattern image of the sample (41). Additionally, as described above, instead of the stage (40) moving in the x-axis and -x-axis, the scanning assembly (80) may move in the x-axis direction and -x-axis direction.

[0138]

[0139] As another embodiment of the brightness correction of the surface shape image of the sample (41) by the image analysis processor (70), as shown in (c) of FIG. 9, the scanning assembly (80) may move the surface of the sample (41) in a single path to correct the brightness of the surface shape image of the sample (41). When moving in a single path, a beam splitter (21, see FIG. 11) that transmits more light than reflects light is included to measure the brightness of the sample (41) itself.

[0140]

[0141] FIG. 11 is a drawing showing a scanning assembly (80) according to the present invention moving in a single path across the surface of a sample (41) to measure the surface brightness of the sample (41).

[0142] Fig. 11 (a) is a drawing showing a white light interferometer (100) according to the present invention applied to a Linick interferometer, and Fig. 11 (b) is a drawing showing a white light interferometer (100) according to the present invention applied to a Michelson interferometer. In the case of a Linick interferometer, the beam splitter (20) may include a first beam splitter (21) and a second beam splitter (23).

[0143] When the scanning assembly (80) moves in a single path across the surface of the sample (41) to measure the surface brightness of the sample (41), the CCD image sensor (60) includes a first CCD image sensor (61) for measuring the brightness of the sample (41) itself and a second CCD image sensor (63) for acquiring an interference pattern image of the surface of the sample (41).

[0144] As described above, the beam splitter (20) includes a beam splitter (21) that transmits more light than reflects light.

[0145] The beam splitter (21) splits the measurement light reflected from the sample (41) and the reflected light reflected from the mirror (30) and transmits them to the first CCD image sensor (61) and the second CCD image sensor (63).

[0146]

[0147] The beam splitter (21) transmits and reflects the measurement light reflected from the sample (41), and the measurement light transmitted from the beam splitter (21) is transmitted to the first CCD image sensor (61), and the measurement light reflected from the beam splitter (21) is transmitted to the second CCD image sensor (63).

[0148] The beam splitter (21) transmits and reflects the reflected light reflected from the mirror (30), and the reflected light transmitted from the beam splitter (21) is transmitted to the second CCD image sensor (63), and the reflected light reflected from the beam splitter (21) is transmitted to the first CCD image sensor (61).

[0149] Since the beam splitter (21) transmits more light than it reflects, the amount of measurement light transmitted to the first CCD image sensor (61) is greater than the amount of reflected light transmitted to the first CCD image sensor (61). Accordingly, the first CCD image sensor (61) can measure the brightness of the sample (41) itself by receiving more measurement light than the reflected light reflected from the mirror (30).

[0150]

[0151] As an example, a beam splitter (21) having a light transmittance and reflection ratio of 90:10 may be applied. When a beam splitter (21) having a light transmittance and reflection ratio of 90:10 is applied, 81% of the total white light is received by the first CCD image sensor (61) of the measurement light transmitted from the beam splitter (21), and 1% of the total white light is received by the first CCD image sensor (61) of the reflected light reflected from the beam splitter (21). Therefore, since the first CCD image sensor (61) limits the reflected light reflected from the mirror (30) to about 1% of the total white light, the brightness of the sample (41) itself can be measured.

[0152] On the other hand, 9% of the total white light is received by the second CCD image sensor (63) from the measurement light reflected from the beam splitter (21), and 9% of the total white light is also received by the second CCD image sensor (63) from the reflected light transmitted from the beam splitter (21). Therefore, the second CCD image sensor (63) can acquire an interference pattern image of the surface of the sample (41) by receiving the same amount of measurement light and reflected light.

[0153]

[0154] Figures 12 and 13 are flowcharts of a method for capturing an instant white light interference pattern image using a white light interferometer according to the present invention.

[0155] The instant white light interference pattern image capturing method of a white light interferometer (100) according to the present invention generates a white light interference pattern signal based on an interference pattern captured by a CCD image sensor (60), extracts a Z value of a zero-crossing point based on the generated white light interference pattern signal, positions a scanning assembly (80) to the position of the extracted Z value of the zero-crossing point, then captures the surface of a sample (41) to generate an interference pattern image, and merges a plurality of interference pattern images to acquire a surface shape image of the sample (41).

[0156] In detail, the instant white light interference pattern image capturing method of the white light interferometer (100) according to the present invention, with reference to FIG. 12, comprises: a step (S100) of generating a white light interference pattern signal based on an interference pattern generated by measurement light reflected from a sample (41) and reflected light reflected from a mirror (30) through a scanning assembly (80) tilted at a predetermined angle with respect to the sample (41); a step (S200) of an image analysis processor (70) analyzing the white light interference pattern signal to extract a Z value of a zero-crossing point where the intensity of light changes abruptly; a step (S300) of an optical movement assembly (81) moving the scanning assembly (80) from the surface of the sample (41) to a position corresponding to the Z value based on the Z value of the zero-crossing point; a step (S400) of a stage movement assembly (50) moving the stage (40) on which the sample (41) is placed in the x-axis direction; a step (S400) of a CCD image sensor (60), It includes a step (S500) of receiving measurement light and reflected light from a scanning assembly (80) to generate a plurality of interference pattern images, and a step (S600) of acquiring a surface shape image of a sample (41) by merging the plurality of interference pattern images by an image analysis processor (70).

[0157] In step (S200), the zero-crossing point means a negative zero-crossing point that exists within a section where the light intensity decreases as the Z value increases.

[0158] In step (S400), the optical movement assembly (81) changes the position of the scanning assembly (80) so that the distance between the scanning assembly (80) and the surface of the sample (41) is maintained at the Z value of the zero-crossing point. The optical movement assembly (81) supports Z tracking between the surface of the sample (41) and the scanning assembly (80), and when a step occurs on the surface of the sample (41), changes the position of the scanning assembly (80) according to the step, so that the distance between the sample (41) and the scanning assembly (80) is maintained at the Z value of the zero-crossing point when scanning the surface of the sample (41).

[0159] The instant white light interference pattern image capturing method of the white light interferometer (100) according to the present invention further includes a step (S700) of correcting the brightness of the surface shape image of the sample (41) when a transparent film exists on the surface of the sample (41), as shown in FIG. 13.

[0160] When a transparent film exists on the surface of the sample (41), step (S400) further includes a step (S410) of measuring the brightness of the sample (41), and step (S700) includes a step (S710) of correcting the brightness of the surface shape image of the sample (41) by removing the brightness of the sample (41) from the surface shape image of the sample (41).

[0161] Step (S410) includes two embodiments of the Double Path method and the Single Path method when measuring the brightness of the sample (41).

[0162] First, with respect to the Double Path method, step (S410) includes a step in which the stage movement assembly (50) moves the stage (40) in the x-axis direction in which the sample (41) is scanned, and in the step in which the stage movement assembly (50) moves the stage (40) in the x-axis direction in which the sample (41) is scanned, the optical movement assembly (81) maintains the scanning assembly (80) at a position 10 μm to 100 μm higher than the Z value of the zero-crossing point with respect to the surface of the sample (41) when the stage (40) is moved in the x-axis direction, so that the CCD image sensor (60) measures the brightness of the sample (41), and a step in which the CCD image sensor (60) measures the brightness of the sample (41), and the stage (40) is moved in the -x-axis direction by the stage movement assembly (50), and the optical movement assembly (81) moves the scanning assembly (80) with respect to the surface of the sample (41). It includes a step of taking an interference pattern image of the sample (41) at the position of the Z value of the zero-crossing point.

[0163] With respect to the Single Path method, step (S410) includes a step of splitting the measurement light reflected from the sample (41) and the reflected light reflected from the mirror (30) by the beam splitter (21) having more light transmission than light reflection, and transmitting the split light to a first CCD image sensor (61) for measuring the brightness of the sample (41) and a second CCD image sensor (63) for acquiring an interference pattern image of the surface of the sample (41), and in the transmitting step, the beam splitter (21) transmits and reflects the measurement light reflected from the sample (41), and the measurement light transmitted by the beam splitter (21) is transmitted to the first CCD image sensor (61), and the measurement light reflected by the beam splitter (21) is transmitted to the second CCD image sensor (63). In the transmitting step, the beam splitter (21) transmits and reflects the reflected light reflected from the mirror (30), and the reflected light transmitted from the beam splitter (21) is transmitted to the second CCD image sensor (63), and the reflected light reflected from the beam splitter (21) is transmitted to the first CCD image sensor (61). In the transmitting step, the first CCD image sensor (61) receives brighter measurement light transmitted from the beam splitter (21) than the reflected light reflected from the beam splitter (21), thereby measuring the brightness of the sample (41).

[0164]

[0165] In this specification, the image analysis processor (70) may be a processor that executes sequential execution processes stored in memory. Alternatively, the image analysis processor (70) may operate as software modules driven and controlled by the processor. Furthermore, the image analysis processor (70) may be a hardware device.

[0166] For reference, the instant white light interference pattern image capturing method of a white light interferometer (100) according to one embodiment of the present invention may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program commands, data files, data structures, etc., alone or in combination. The program commands recorded on the medium may be those specially designed and configured for the present invention or may be those known and usable to those skilled in the art of computer software. Examples of the computer-readable medium may include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands such as ROMs, RAMs, and flash memories. Examples of the program commands include not only machine codes generated by a compiler but also high-level language codes that can be executed by a computer using an interpreter, etc. The above-described hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

[0167] In this specification, the term "unit" includes a unit realized by hardware, a unit realized by software, and a unit realized using both. Furthermore, a single unit may be realized using two or more pieces of hardware, and two or more units may be realized by a single piece of hardware.

[0168] The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it should be noted that the scope of protection of the present invention may not be limited by obvious modifications or substitutions within the technical field to which the present invention pertains.

Claims

1. In an instant white light interferometer (WLI) that acquires the shape of a sample by photographing an interference pattern generated by the measurement light reflected from the sample and the reflected light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample, The above white light interferometer, A light source that provides white light; A stage on which a sample is placed; A mirror having a reflective surface; A beam splitter that divides the path of white light provided from the light source into the sample side and the mirror side; A stage movement assembly that moves the stage in the X-axis direction in which the sample is scanned; An optical movement assembly for moving the scanning assembly in the z-axis direction toward the sample; A CCD image sensor (Charge Coupled Device image sensor) that receives the measurement light and the reflected light and photographs an interference pattern generated by the measurement light and the reflected light; and An image analysis processor that generates a white light interference fringe signal (WLI Fringe) based on the above interference fringe; Includes, The image analysis processor analyzes the white light interference pattern signal to extract the Z value of the zero-crossing point where the light intensity changes rapidly, The optical movement assembly moves the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value, The stage movement assembly moves the stage in the x-axis direction after the scanning assembly moves to a position corresponding to the Z value, The CCD image sensor generates a plurality of interference pattern images by receiving the measurement light and the reflected light from the scanning assembly, which are maintained at a position corresponding to the Z value while the stage moving assembly moves the stage, The image analysis processor acquires a surface shape image of the sample by merging the plurality of interference pattern images, The image analysis processor is an instantaneous white light interferometer that corrects the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

2. In claim 1, The above image analysis processor, when correcting the brightness of the surface shape image of the sample, An instantaneous white light interferometer characterized by measuring the brightness of the sample and correcting the brightness of the surface shape image of the sample by removing the brightness of the sample from the surface shape image of the sample.

3. In claim 2, The stage movement assembly moves the stage in the x-axis direction in which the sample is scanned, and then moves the stage again in the -x-axis direction. The above optical movement assembly, When the stage moves in the x-axis direction, the scanning assembly is maintained at a position 10 μm to 100 μm higher than the Z value with respect to the surface of the sample, so that the CCD image sensor measures the brightness of the sample, An instantaneous white light interferometer that maintains the scanning assembly at a position corresponding to the Z value with respect to the surface of the sample when the stage is moved in the -x-axis direction, so that the CCD image sensor generates an interference pattern image of the sample.

4. In claim 2, The above CCD image sensor, A first CCD image sensor for measuring the brightness of the sample; and A second CCD image sensor for acquiring an interference pattern image of the sample surface; The above beam splitter includes a beam splitter having more light transmission than light reflection, The beam splitter splits the measurement light reflected from the sample and the reflected light reflected from the mirror and transmits them to the first CCD image sensor and the second CCD image sensor, The above beam splitter transmits and reflects the measurement light reflected from the sample, The measurement light transmitted from the beam splitter is transmitted to the first CCD image sensor, The measurement light reflected from the beam splitter is transmitted to the second CCD image sensor, The above beam splitter transmits and reflects the reflected light reflected from the mirror, The reflected light transmitted from the beam splitter is transmitted to the second CCD image sensor, The reflected light reflected from the beam splitter is transmitted to the first CCD image sensor, An instantaneous white light interferometer in which the first CCD image sensor receives measurement light transmitted from the beam splitter that is brighter than the reflected light reflected from the beam splitter to measure the brightness of the sample.

5. In claim 4, The above beam splitter is a beam splitter with a light transmission and reflection ratio of 90:10, The measurement light transmitted from the beam splitter is received by the first CCD image sensor at 81% of the white light, and the reflected light reflected from the beam splitter is received by the first CCD image sensor at 1% of the white light, so that the first CCD image sensor measures the brightness of the sample. An instantaneous white light interferometer, wherein 9% of the white light is received by the second CCD image sensor from the measurement light reflected from the beam splitter, and 9% of the white light is received by the second CCD image sensor from the reflected light transmitted from the beam splitter, so that the second CCD image sensor acquires an interference pattern image of the sample surface.

6. In an instant white light interferometer (WLI) that acquires the shape of a sample by photographing an interference pattern generated by the measurement light reflected from the sample and the reflected light reflected from the mirror through a scanning assembly inclined at a predetermined angle with respect to the sample, The above white light interferometer, A light source that provides white light; A stage on which a sample is placed; A mirror having a reflective surface; A beam splitter that divides the path of white light provided from the light source into the sample side and the mirror side; An optical movement assembly that moves the scanning assembly in the x-axis direction in which the sample is scanned and in the z-axis direction toward the sample; A CCD image sensor (Charge Coupled Device image sensor) that receives the measurement light and the reflected light and photographs an interference pattern generated by the measurement light and the reflected light; and An image analysis processor that generates a white light interference fringe signal (WLI Fringe) based on the above interference fringe; Includes, The image analysis processor analyzes the white light interference pattern signal to extract the Z value of the zero-crossing point where the light intensity changes rapidly, The optical movement assembly moves the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value, and then moves the scanning assembly in the x-axis direction while maintaining the scanning assembly at the position corresponding to the Z value with respect to the surface of the sample. The CCD image sensor receives the measurement light and the reflected light from the scanning assembly while the optical movement assembly moves the scanning assembly in the X-axis direction, and generates a plurality of interference pattern images. The image analysis processor acquires a surface shape image of the sample by merging the plurality of interference pattern images, The image analysis processor is an instantaneous white light interferometer that corrects the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

7. In a method for capturing an instant white light interference pattern image of a white light interferometer, the method comprises: A step of generating a white light interference pattern signal based on an interference pattern generated by a measurement light reflected from a sample and a reflected light reflected from a mirror through a scanning assembly inclined at a predetermined angle with respect to the sample; A step in which the image analysis processor analyzes the white light interference pattern signal to extract the Z value of the zero-crossing point where the light intensity changes abruptly; A step of the optical movement assembly moving the scanning assembly from the surface of the sample to a position corresponding to the Z value based on the Z value; A stage moving assembly moves the stage on which the sample is placed in the x-axis direction; A step of generating a plurality of interference pattern images by a CCD image sensor receiving the measurement light and the reflected light from the scanning assembly; and A step in which the image analysis processor acquires a surface shape image of the sample by merging the plurality of interference pattern images; Includes, An instant white light interference pattern image capturing method using a white light interferometer, wherein the method further includes a step of the image analysis processor correcting the brightness of the surface shape image of the sample when a transparent film exists on the surface of the sample.

8. In claim 7, The step of the stage movement assembly moving the stage on which the sample is placed in the x-axis direction is as follows: Further comprising a step of measuring the brightness of the sample, The step of correcting the brightness of the surface shape image of the above sample is: An instant white light interference pattern image capturing method using a white light interferometer, comprising a step of correcting the brightness of a surface shape image of a sample by removing the brightness level of the sample from the surface shape image of the sample.

9. In claim 8, The step of measuring the brightness of the above sample is: The stage movement assembly includes a step of moving the stage in the x-axis direction in which the sample is scanned, In the step of the stage movement assembly moving the stage in the x-axis direction in which the sample is scanned, the optical movement assembly, An instant white light interference pattern image capturing method of a white light interferometer, characterized in that when the stage is moved in the x-axis direction, the scanning assembly is maintained at a position 10 μm to 100 μm higher than the Z value with respect to the surface of the sample, so that the CCD image sensor measures the brightness of the sample.

10. In claim 8, The step of measuring the brightness of the above sample is: A step of splitting the measurement light reflected from the sample and the reflected light reflected from the mirror by a beam splitter having more light transmission than light reflection, and transmitting the split light to a first CCD image sensor for measuring the brightness of the sample and a second CCD image sensor for acquiring an interference pattern image of the sample surface, In the above transmitting step, The above beam splitter transmits and reflects the measurement light reflected from the sample, The measurement light transmitted from the beam splitter is transmitted to the first CCD image sensor, The measurement light reflected from the beam splitter is transmitted to the second CCD image sensor, The above beam splitter transmits and reflects the reflected light reflected from the mirror, The reflected light transmitted from the beam splitter is transmitted to the second CCD image sensor, The reflected light reflected from the beam splitter is transmitted to the first CCD image sensor, An instant white light interference pattern image capturing method of a white light interferometer, wherein the first CCD image sensor receives measurement light transmitted from the beam splitter that is brighter than the reflected light reflected from the beam splitter to measure the brightness of the sample.

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