EP-4741759-A1 - SLIDING-TYPE WHITE LIGHT INTERFEROMETER

EP4741759A1EP 4741759 A1EP4741759 A1EP 4741759A1EP-4741759-A1

Abstract

Disclosed is a sliding-type white light interferometer configured to continuously photograph an interference pattern through a scanning assembly which is inclined at a predetermined angle with respect to a sample, thereby acquiring the shape of the sample at a more improved speed. The sliding-type white light interferometer includes a light source, a stage, a mirror, a beam splitter, a stage moving assembly, a CCD image sensor, and an image analysis processor. The beam splitter makes a path change such that the path of white light provided to the sample has a predetermined angle with the sample. The stage moving assembly moves the stage in the X-axis direction in which the sample is scanned while the path of white light maintains at a predetermined angle with the sample. The CCD image sensor continuously photographs an interference pattern generated by measured light reflected from the surface of the sample and reflected light reflected from the mirror while the stage is moved in the X-axis direction, thereby generating a plurality of interference pattern images.

Inventors

JO, AHJIN
AHN, BYOUNG-WOON
KIM, HYUNTAE

Assignees

Park Systems Corp.

Dates

Publication Date: 20260513
Application Date: 20240705

Claims (18)

A sliding-type white light interferometer comprising: a light source providing white light; a stage on which a sample is placed; a mirror having a reflective surface; a beam splitter which splits a path of white light provided from the light source into the sample side and the mirror side; a stage moving assembly which moves the stage; a CCD (Charge Coupled Device) image sensor by receiving from the beam splitter the measured light reflected from the surface of the sample and reflected light reflected from the mirror, photographing an interference fringe generated by the measured light and reflected light to generate a plurality of interference fringe images while the stage moving assembly moves the stage; and an image analysis processor for generating a white light interference fringe (WLI fringe) by accumulating the plurality of interference fringe images, wherein the beam splitter makes a path change such that the path of white light provided to the sample has a predetermined angle with the sample, thereby the white light is irradiated to the sample to have the predetermined angle, the stage moving assembly moves the stage in X-axis direction in which the sample is scanned while the path of white light remains at the predetermined angle with the sample, and the CCD image sensor continuously photographs an interference fringe generated by measured light reflected from the surface of the sample and reflected light reflected from the mirror while the stage is moved in the X-axis direction, thereby generating a plurality of interference fringe images.
The sliding-type white light interferometer according to claim 1, the stage moving assembly, when moving the stage in the X-axis direction, moves the stage toward the beam splitter in the Z-axis direction, thereby changing the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometer according to claim 2, characterized in that the image analysis processor, when accumulating the plurality of interference fringe images, aligns the plurality of interference fringe images to the same X-position of each of the interference fringe images to generate a cumulative white light interference fringe.
The sliding-type white light interferometer according to claim 2, the stage moving assembly, when moving the stage in the X-axis direction, reciprocates the stage in the Z-axis and the -Z-axis directions to change the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometer according to claim 2, characterized in that the stage moving assembly, when moving the stage in the Z-axis direction, moves the stage by a predetermined length, and the predetermined length is 60 to 80 nm.
The sliding-type white light interferometer according to claim 1, comprising a plurality of the CCD image sensors which photograph different frames of the sample, each of the plurality of CCD image sensors generating an interference fringe image based on measurement light reflected from different specific surfaces of the sample.
A sliding-type white light interferometry (WLI) in which is configured to continuously photograph an interference fringe through a scanning assembly which is inclined at a predetermined angle with respect to a sample, to acquire the shape of the sample, wherein the interference fringe is generated by measurement light reflected from the sample and reflection light reflected from a mirror, the scanning assembly comprising: a light source providing white light; the mirror having a reflection surface; a beam splitter which splits the path of the white light provided by the light source into the sample side and the mirror side; and a CCD (Charge Coupled Device) image sensor which receives from the beam splitter measurement light reflected from the sample and reflected light reflected from the mirror and photographs an interference fringe generated by the measurement light and the reflected light; wherein the white light interferometry further comprises, an optical moving assembly which moves the scanning assembly; and an image analysis processor which accumulates a plurality of interference fringes photographed by the CCD image sensor while the optical moving assembly moves the scanning assembly to generate a white light interference fringe (WLI Fringe), wherein the beam splitter makes a path change such that the path of white light provided to the sample has a predetermined angle with the sample, thereby the white light is irradiated to the sample to have the predetermined angle, the optical moving assembly moves the scanning assembly in X-axis direction in which the sample is scanned while the path of white light remains at the predetermined angle with the sample, and the CCD image sensor continuously photographs an interference fringe generated by measured light reflected from the surface of the sample and reflected light reflected from the mirror while the scanning assembly moves in the X-axis direction, thereby generating a plurality of interference fringe images.
The sliding-type white light interferometry according to claim 7, the optical moving assembly, when moving the scanning assembly in the X-axis direction, moves the scanning assembly toward the sample in the Z-axis direction, thereby changing the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometry according to claim 8, characterized in that the image analysis processor, when accumulating the plurality of interference fringe images, aligns the plurality of interference fringe images to the same X-position of each of the interference fringe images to generate a cumulative white light interference fringe.
The sliding-type white light interferometry according to claim 8, the optical moving assembly, when moving the scanning assembly in the X-axis direction, reciprocates the scanning assembly in the Z-axis and the -Z-axis directions to change the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometry according to claim 8, characterized in that , the optical moving assembly, when moving the scanning assembly in the Z-axis direction, moves the scanning assembly by a predetermined length, and the predetermined length is 60 to 80 nm.
The sliding-type white light interferometry according to claim 7, comprising a plurality of the CCD image sensors which photograph different frames of the surface of the sample, each of the plurality of CCD image sensors generating an interference fringe image based on measurement light reflected from different specific surfaces of the sample.
A sliding-type white light interferometry (WLI) in which is configured to continuously photograph an interference fringe through a scanning assembly which is inclined at a predetermined angle with respect to a sample, to acquire the shape of the sample, wherein the interference fringe is generated by measurement light reflected from the sample and reflection light reflected from a mirror, the scanning assembly comprising: a light source providing white light; a stage on which a sample is placed; a mirror having a reflection surface; a beam splitter which splits the path of the white light provided by the light source into the sample side and the mirror side; and a CCD (Charge Coupled Device) image sensor which receives from the beam splitter measurement light reflected from the sample and reflected light reflected from the mirror and photographs an interference fringe generated by the measurement light and the reflected light; wherein the white light interferometry further comprises, a stage moving assembly which moves the stage in the X-axis direction in which the sample is scanned; an optical moving assembly which moves the scanning assembly toward the sample in the Z-axis direction; and an image analysis processor which accumulates a plurality of interference fringes photographed by the CCD image sensor while the stage moving assembly moves the stage in the X-axis direction and the optical moving assembly moves the scanning assembly in the Z-axis direction to generate a white light interference fringe (WLI Fringe), wherein the beam splitter makes a path change such that the path of white light provided to the sample has a predetermined angle with the sample, thereby the white light is irradiated to the sample to have the predetermined angle, the stage moving assembly moves the stage in X-axis direction while the path of white light remains at the predetermined angle with the sample, and the CCD image sensor continuously photographs an interference fringe generated by measured light reflected from the surface of the sample and reflected light reflected from the mirror while the stage is moved in the X-axis direction, thereby generating a plurality of interference fringe images.
The sliding-type white light interferometry according to claim 13, the optical moving assembly, when the stage moving assembly moves the stage in the X-axis direction, moves the scanning assembly in the Z-axis, thereby changing the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometry according to claim 14, characterized in that the image analysis processor, when accumulating the plurality of interference fringe images, aligns the plurality of interference fringe images to the same X-position of each of the interference fringe images to generate a cumulative white light interference fringe.
The sliding-type white light interferometry according to claim 14, the optical moving assembly, when the stage moving assembly moves the stage in the X-axis direction, reciprocates the scanning assembly in the Z-axis and the -Z-axis directions to change the interference fringe during continuous photographing of the interference fringe.
The sliding-type white light interferometry according to claim 14, characterized in that , the optical moving assembly, when moving the scanning assembly in the Z-axis direction, moves the scanning assembly by a predetermined length, and the predetermined length is 60 to 80 nm.
The sliding-type white light interferometry according to claim 13, comprising a plurality of the CCD image sensors which photograph different frames of the surface of the sample, each of the plurality of CCD image sensors generating an interference fringe image based on measurement light reflected from different specific surfaces of the sample.

Description

Technical Field The present invention relates to a sliding-type white light interferometer, and more particularly, to a sliding-type white light interferometer in which interference fringes are continuously photographed through a scanning assembly inclined at a predetermined angle with respect to a sample to acquire the shape of the sample. Background Art 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 to measure three-dimensional shape information of samples with a three-dimensional nanostructures or micrometer structures. A white light interferometry that uses interference phenomenon of white light has been used to measure the three-dimensional shape information of the sample. A general white light interferometry uses a beam splitter that separates a white light source and generates a path toward the sample and the mirror, respectively. The white light irradiated to the sample and the mirror, respectively by the beam splitter is reflected and then recombined and transmitted to the CCD (charge-coupled device) image sensor, which photographs interference fringe images by the combined light reflected from the sample and the mirror, respectively. The image analysis processor analyzes the interference fringe image photographed by the CCD image sensor to generate 3D shape information of the sample. At this time, the sample is placed on the stage, and the stage is moved along the path axis (generally the Z-axis) of the light source by a separate driving assembly to generate a path difference between the sample side and the mirror side. The interference fringe image photographed by the CCD image sensor forms different interference fringe images according to a 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 fringes from which the different interference fringe images are accumulated. Meanwhile, a conventional white light interferometer uses a so-called vertical scanning interferometry in which an interference fringe is acquired according to a change in the Z-axis distance between a stage on which a sample is placed and an optical system such as the beam splitter and the CCD image sensor as described above. In the vertical scanning interferometry, Z-axis distance between a stage and an optical system is changed at a specific position on the sample to acquire interference fringe of one frame, the sample or the optical system is shifted to an X-axis by a certain distance, and then the Z-axis distance between the stage and the optical system is changed again to acquire an interference fringe of another adjacent frame, and then the acquired plural interference fringes are accumulated or stitched to scan the sample. However, the above-described vertical scanning interferometry has a problem in that it takes a long time to scan the shape of the sample because it requires acquiring an interference fringe by changing the Z-axis distance between the stage and the optical system at each specific location, and then acquiring an interference fringe 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. Disclosure of Invention Technical Problem An object of the present invention for solving the above-described problems is to provide a sliding-type white light interferometer in which interference fringes are continuously photographed through a scanning assembly inclined at a predetermined angle with respect to a sample to acquire the shape of the sample at a further improved speed. Solution to Problem In order to achieve the above object, a sliding-type white light interferometer according to an embodiment of the present invention includes a light source providing white light; a stage on which a sample is placed; a mirror having a reflective surface; a beam splitter which splits a path of white light provided from the light source into the sample side and the mirror side; a stage moving assembly which moves the stage; a CCD (Charge Coupled Device) image sensor by receiving from the beam splitter the measured light reflected from the sample and reflected light reflected from the mirror, photographing an interference fringe generated by the measured light and the reflected light to generate a plurality of interference fringe images while the stage moving assembly moves the stage; and an image analysis processor for generating a white light interference fringe (WLI fringe) by accumulating the plurality of interference fringe images, wherein the beam splitter makes a path change such that the path of white light provided to the sample side has a predetermined angle with the sample side, thereby the white light is irradiated to the sample