System and method for measuring surface shape of thin film structure including heterogeneous materials

Abstract

The present invention relates to a system and a method for measuring a surface shape of a thin film structure including heterogeneous materials and, more specifically, to a system for measuring a surface shape of a thin film structure using an interferometer, wherein light is incident on the interferometer and reflected by each of an object to be measured and a reference surface, so that interference light is acquired through a camera. The system for measuring a surface shape of a thin film structure comprises: a wavelength selection unit for selecting a wavelength of light to remove a phase shift of a thin film; an interferometer for illuminating a surface of the thin film structure with light to measure an interference signal; and an analysis unit for extracting the selected wavelength, measuring a phase at the wavelength, and analyzing a surface shape of the thin film structure.

Description

System and method for extracting surface shape of thin film structures containing heterogeneous materials

[0001] The present invention relates to a system for extracting the surface shape of a thin film structure containing heterogeneous materials and a method for extraction.

[0002] Methods for measuring the fine surface shape of precision parts include the stylus type measurement method, scanning electron microscope measurement method, scanning probe microscope measurement method, phase shifting interferometry measurement method, white-light scanning interferometry measurement method, and confocal scanning microscope measurement method.

[0003] These measurement methods primarily measure geometric shapes on a two-dimensional plane, such as circles, lines, angles, and line widths, or inspect defects, foreign substances, and asymmetry in patterns, and are based on probe systems and image processing technologies consisting mainly of optical microscopes, illumination, and imaging elements represented by CCD cameras.

[0004] Among these measurement methods, white light scanning interferometer and optical phase shift interferometer (PSI) measurement methods are gaining attention as non-contact measurement methods that are widely applied to three-dimensional measurements of micro-shapes, ranging from semiconductor pattern measurement to surface roughness measurement of soft materials, BGA (Ball Grid Array) ball measurement, laser marking pattern measurement, and via hole measurement.

[0005] Although these two measurement methods are based on different measurement principles, they can be implemented in the same optical and measurement system except for the use of multiple wavelengths and monochromatic wavelengths; therefore, commercial measurement systems can utilize both methods together.

[0006] These measurement methods utilize optical interference signals in which light is expressed as bright or dark depending on the optical path difference between two beams of light that originate simultaneously from an arbitrary reference point, travel along different optical paths, and then merge.

[0007] As a prior art document related to such white light interferometers, Korean Registered Patent No. 10-0598572 (July 7, 2006) proposed White-light Scanning Interferometry (WSI) to measure information regarding the thickness of a transparent thin film layer or its surface shape during the process of applying a transparent thin film layer on the surface of an opaque metal layer during the semiconductor and LCD (Liquid Crystal Display) manufacturing process.

[0008] The basic measurement principle of this white light scanning interferometry utilizes the short coherence length characteristic of white light. More specifically, it utilizes the principle that an interference signal is generated only when the reference light and the measurement light separated by a beam splitter experience nearly the same optical path difference. When the object to be measured is moved in the direction of the optical axis by a transport means such as a PZT actuator in minute intervals of several nanometers and the interference signal at each measurement point within the measurement area is observed, a short interference signal is generated at the point where the same optical path difference as the reference mirror occurs. By calculating the location of the generation of this interference signal at all measurement points within the measurement area, information regarding the three-dimensional shape of the measurement surface is obtained, and the surface shape of the thin film layer is measured from the obtained three-dimensional information.

[0009] FIG. 1 is a drawing illustrating a surface shape measuring device using white light scanning interferometry. As illustrated in FIG. 1, a conventional surface shape measuring device includes a light source, a beam splitting unit, an interference module, an imaging unit, a transfer unit, and a control unit. In this conventional white light interferometer, the coherent range is approximately 4 to 20 μm, and the period of the interference fringes is approximately 0.3 μm. Therefore, in order to measure a three-dimensional shape with varying heights, interference fringes must be acquired over the entire height by moving in steps at very short intervals, which results in a longer time required for measurement.

[0010] In addition, FIG. 2 is another configuration diagram of a conventional three-dimensional shape measuring device, wherein illumination light from a light source is divided through a beam splitter and irradiated onto a reference plane and a measurement target surface of the object to be measured, respectively, and after being reflected from a reference mirror and a measurement surface, is combined through a beam splitter.

[0011] The combined interference fringes are detected using a capturing device such as a CCD camera, and the phase of the interference fringes is calculated by a control computer, or the point of maximum coherence is extracted from the envelope of the interference fringes to measure the height.

[0012] In the above-described three-dimensional shape measuring device, interference fringes appear at the point where the distance from the beam splitter to the measurement surface and the distance from the beam splitter to the reference mirror coincide. Accordingly, for a measurement target having a step difference, the interference fringe acquisition section must be divided uniformly according to height information, and then interference fringes must be acquired while slightly moving the reference mirror or the measurement target for each divided section, and the surface shape must be measured by synthesizing the acquired multiple interference fringes.

[0013] As a means for adjusting the distance from the beam splitter to the measuring plane and the distance from the beam splitter to the reference mirror, as shown in FIG. 2, the entire support means (such as a tilting stage) is used to support the reference mirror so that the distance between the beam splitter and the reference mirror can be adjusted by using an actuator (not shown).

[0014] In addition, as advanced packaging technology emerges in the semiconductor packaging field, wafer-level packaging technology is being developed in the process.

[0015] In addition, in the case of thin film structures containing heterogeneous materials, specimens can be broadly divided into metal and thin film structures that cause phase changes upon reflection.

[0016] In thin film regions, multiple reflections caused by the film thickness lead to measurement errors during surface shape measurement. Therefore, to accurately measure only the surface shape, these errors must be compensated for. However, compensating for such phase errors requires an additional measurement system for the thin film, which has the disadvantages of being time-consuming and allowing the film's measurement error to affect the shape measurement.

[0017] Since the metallic part has a complex refractive index determined by the extinction coefficient (k), the amount of phase change is shifted by the extinction coefficient. And if the refractive index of the metal is known, the phase change can be compensated for by the Fresnel coefficient.

[0018] Due to multiple reflections of the specimen, the reflection coefficient is more complex, along with the Fresnel coefficient at the interface between the layer and the refractive index. If all parameters are known, the phase change can be compensated for; however, the film thickness (d) is unknown and must be measured using other techniques based on optimization.

[0019] Accordingly, the present invention has been devised to solve the aforementioned conventional problems. According to an embodiment of the present invention, the purpose is to provide a surface shape extraction system and method for thin film structures containing heterogeneous materials, which can be applied in the production process by replacing time-consuming measurement techniques such as conventional AFM, as a technology for precisely measuring surfaces for bonding wafers and wafers, wafers and dies, or dies and dies in the hybrid bonding process of HBM.

[0020] According to an embodiment of the present invention, the purpose is to provide a surface shape extraction system and extraction method for a thin film structure containing heterogeneous materials, which can be utilized not only in the semiconductor field but also in the field of manufacturing displays and thin film structures, where surface shapes are measured at high speed and precisely.

[0021] According to an embodiment of the present invention, the surface shape of a specimen can be precisely measured by compensating for phase changes caused by differences in the refractive index of materials in a thin film structure having heterogeneous materials and phase changes occurring in the thin film structure, and the purpose is to provide a method for compensating based on theory or eliminating in principle, instead of existing methods of measuring the refractive index of a specimen or analyzing the thin film structure.

[0022] According to an embodiment of the present invention, the purpose is to provide a surface shape extraction system and method for a thin film structure containing heterogeneous materials, which can be utilized in a relatively stable semiconductor and display manufacturing process by selecting a wavelength at which the phase change caused by the thin film in the thin film structure becomes zero, thereby fundamentally eliminating the effect of the thin film from the phase measured by the interferometer, and by directly compensating for the phase change occurring during reflection through the refractive index information of the material used.

[0023] According to an embodiment of the present invention, the purpose is to provide a surface shape extraction system and extraction method for a thin film structure containing heterogeneous materials, which enables high-speed measurement because it does not undergo the optimization process used in conventional reflectance measuring instruments and ellipsometers.

[0024] Furthermore, according to an embodiment of the present invention, the purpose is to provide a system and method for extracting the surface shape of a thin film structure containing heterogeneous materials, which is a measurement method applicable to all interferometers utilizing multi-wavelength light sources, such as white light scanning interferometers, dispersion interferometers, and wavelength scanning interferometers; capable of measuring only the surface shape regardless of the internal structure of the thin film structure; capable of extracting only the surface shape by selecting a wavelength that eliminates the thin film effect in not only single-layer thin films but also multi-layer thin films; and capable of precise high-speed measurement because the surface shape is measured by directly measuring the phase.

[0025] Meanwhile, the technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0026] The first objective of the present invention can be achieved by a surface shape extraction system for a thin film structure using an interferometer, wherein light is incident on the interferometer, reflected off a measurement target and a reference plane respectively, and the interfered light is acquired through a camera, the system comprising: a wavelength selection unit for selecting a wavelength of light to eliminate phase change of the thin film structure; an interferometer for irradiating light onto the surface of the thin film structure to measure an interference signal; and an analysis unit for extracting the selected wavelength, measuring the phase at the wavelength, and analyzing the surface shape of the thin film structure.

[0027] And the above thin film structure may be characterized as a thin film structure including the above heterogeneous material, comprising a metal and a thin film structure.

[0028] In addition, the interferometer acquires interference signals for each of the metal and the thin film structure, the wavelength selection unit selects a specific wavelength at which the phase change in the thin film structure is minimized, and the analysis unit measures the phase signal of the thin film structure at the specific wavelength and analyzes the surface shape information of the thin film structure including the heterogeneous material by compensating for the phase change upon reflection through the refractive index of the metal.

[0029] And the phase change upon reflection through the refractive index of the above metal can be characterized as being expressed by the following mathematical formula 1.

[0030] [Mathematical Formula 1]

[0031]

[0032] In the above mathematical formula 1, n1 is the refractive index of air and n2 is the refractive index of metal.

[0033] In addition, the phase change in the above thin film structure is expressed by the following Equation 2, and the wavelength selector is R film This can be characterized by selecting the wavelength that becomes the minimum.

[0034] [Mathematical Formula 2]

[0035]

[0036] In the above mathematical formula 2, r 12 r is the reflection coefficient at the boundary between air and the thin film. 23 n is the reflection coefficient at the boundary between the thin film and the base, n2 is the refractive index of the thin film, and d is the thickness of the thin film.

[0037] And the above R film The condition for =0 can be characterized by being expressed by the following mathematical formula 3.

[0038] [Mathematical Formula 3]

[0039]

[0040] The above ∠r 23 It is the amount of phase change during reflection due to the difference in refractive index at the boundary between the thin film and the base.

[0041] In addition, the interference signal of the metal and the interference signal of the thin film structure are Fourier transformed, and Gaussian fitting is performed on the FFT signal of the thin film structure to obtain an FFT signal with Gaussian components removed, and the wavelength selection unit selects the wavelength of the minimum value in the FFT signal with Gaussian components removed as the specific wavelength.

[0042] And the above interferometer may be characterized as being at least one of a white light scanning interferometer, a dispersion interferometer, a phase shift interferometer, and a wavelength scanning interferometer.

[0043] The second objective of the present invention can be achieved by a method for extracting the surface shape of a thin film structure using an interferometer, wherein light is incident on the interferometer, reflected off a measurement target and a reference plane respectively, and the interfered light is acquired through a camera, the method comprising: a step of irradiating the surface of the thin film structure with light through the interferometer to measure an interference signal; a step of a wavelength selection unit selecting a wavelength of light to eliminate phase change of the thin film structure; and a step of an analysis unit extracting the selected wavelength, measuring phase information at the wavelength, and analyzing the surface shape information of the thin film structure.

[0044] And the thin film structure is a thin film structure including the heterogeneous material, comprising a metal and a thin film structure, and in the step of measuring the interference signal, an interference signal for each of the metal and the thin film structure is obtained, and in the step of selecting the wavelength, a specific wavelength at which the phase change in the thin film structure is minimized is selected, and in the step of analyzing, the phase signal of the thin film structure at the specific wavelength is measured, and the surface shape information of the thin film structure including the heterogeneous material is analyzed by compensating for the phase change upon reflection through the refractive index of the metal.

[0045] In addition, the method may be characterized by including: a step of performing a Fourier transform on the interference signal of the metal and the interference signal of the thin film structure; a step of obtaining an FFT signal with Gaussian components removed by performing Gaussian fitting on the FFT signal of the thin film structure; and a step in which the wavelength selection unit selects the wavelength of the minimum value in the FFT signal with Gaussian components removed as the specific wavelength.

[0046] And the phase change upon reflection through the refractive index of the above metal can be characterized as being expressed by the following mathematical formula 1.

[0047] [Mathematical Formula 1]

[0048]

[0049] In the above mathematical formula 1, n1 is the refractive index of air and n2 is the refractive index of metal.

[0050] In addition, the phase change in the above thin film structure is expressed by the following Equation 2, and the wavelength selector is R film This can be characterized by selecting the wavelength that becomes the minimum.

[0051] [Mathematical Formula 2]

[0052]

[0053] In the above mathematical formula 2, r 12 r is the reflection coefficient at the boundary between air and the thin film. 23n is the reflection coefficient at the boundary between the thin film and the base, n2 is the refractive index of the thin film, and d is the thickness of the thin film.

[0054] According to the surface shape extraction system and extraction method of a thin film structure containing heterogeneous materials according to an embodiment of the invention, the technology for precisely measuring surfaces for bonding wafers in wafer-level packaging has the effect of being applicable in the production process by replacing time-consuming measurement technologies such as conventional AFM.

[0055] According to the surface shape extraction system and extraction method of a thin film structure including heterogeneous materials according to an embodiment of the present invention, there is an advantage that it can be utilized not only in the semiconductor field but also in fields where surface shapes are measured at high speed and precisely during the manufacturing process of displays and thin film structures.

[0056] According to the surface shape extraction system and extraction method of a thin film structure including heterogeneous materials according to an embodiment of the present invention, the surface shape of a specimen can be precisely measured by compensating for phase changes caused by the difference in refractive index of the materials in a thin film structure having heterogeneous materials and phase changes occurring in the thin film structure, and can provide a method to compensate based on theory or eliminate in principle instead of existing methods of measuring the refractive index of the specimen or analyzing the thin film structure.

[0057] According to the surface shape extraction system and extraction method of a thin film structure including heterogeneous materials according to an embodiment of the present invention, in particular, by selecting a wavelength at which the phase change caused by the thin film in the thin film structure becomes zero, the effect of the thin film can be fundamentally eliminated from the phase measured by the interferometer, and furthermore, by directly compensating for the phase change occurring during reflection through the refractive index information of the material used, there is an advantage that it can be utilized in a relatively stable manufacturing process for semiconductors and displays.

[0058] According to the surface shape extraction system and extraction method of a thin film structure including heterogeneous materials according to an embodiment of the present invention, high-speed measurement is possible because it does not undergo the optimization process used in conventional reflectance measuring instruments and ellipsometers.

[0059] Furthermore, according to the surface shape extraction system and extraction method of a thin film structure including heterogeneous materials according to an embodiment of the present invention, it is a measurement method that can be used with any interferometer utilizing a multi-wavelength light source, such as a white light scanning interferometer, a dispersion interferometer, or a wavelength scanning interferometer. It is capable of measuring only the surface shape regardless of the internal structure of the thin film structure, and can extract only the surface shape by selecting a wavelength that eliminates the thin film effect in not only single-layer thin films but also multi-layer thin films. Since the surface shape is measured by directly measuring the phase, it has the effect of enabling precise high-speed measurement.

[0060] Meanwhile, the effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0061] FIG. 1 is a drawing illustrating a surface shape measuring device using white light scanning interferometry according to the prior art.

[0062] FIG. 2 is a configuration diagram of another three-dimensional shape measuring device according to the prior art,

[0063] Figure 3 is an example of a thin film structure containing heterogeneous materials (semiconductor specimen).

[0064] FIG. 4 is a flowchart of a method for extracting the surface shape of a thin film structure including heterogeneous materials according to an embodiment of the present invention.

[0065] FIG. 5 is an example of a white light scanning interferometer according to an embodiment of the present invention,

[0066] Figure 6 shows an example of surface shape information measured according to an embodiment of the present invention.

[0067] Hereinafter, the configuration, function, and extraction method of a surface shape extraction system for a thin film structure containing heterogeneous materials according to an embodiment of the present invention will be described.

[0068] Figure 3 shows an example of a thin film structure (semiconductor specimen) containing heterogeneous materials.

[0069] And Fig. 4 illustrates a flowchart of a method for extracting the surface shape of a thin film structure including heterogeneous materials according to an embodiment of the present invention.

[0070] The present invention is a method for precisely and rapidly measuring the surface shape of a thin film structure containing various materials.

[0071] As illustrated in FIG. 1, in the case of a thin film structure containing heterogeneous materials, the specimen can be broadly divided into a metal and a thin film structure that cause a phase change upon reflection. That is, the thin film structure (specimen) according to the embodiment of the present invention is a thin film structure containing the heterogeneous materials, comprising a metal and a thin film structure. A phase change occurs upon reflection from this metal, and a phase change also occurs in the thin film structure. Therefore, according to the embodiment of the present invention, such a phase change can be rapidly eliminated without separate complex algorithm processing.

[0072] According to an embodiment of the present invention, a surface shape extraction system for a thin film structure using an interferometer, wherein light is incident on the interferometer, reflected off a measurement target and a reference plane respectively, and the interfered light is acquired through a camera, comprises an interferometer, a wavelength selection unit, an analysis unit, etc.

[0073] The wavelength selector selects the wavelength of light to eliminate phase changes in the thin film structure.

[0074] An interferometer is configured to measure interference signals by irradiating light onto the surface of a thin-film structure.

[0075] In addition, the analysis unit extracts a selected wavelength and measures the phase at the wavelength to analyze the surface shape of the thin film structure.

[0076] That is, the interferometer acquires interference signals for each of the metal and the thin film structure, and the wavelength selector selects a specific wavelength at which the phase change in the thin film structure is minimized.

[0077] The analysis unit measures the phase signal of the thin film structure at a specific wavelength and analyzes the surface shape information of the thin film structure containing the heterogeneous material by compensating for the phase change upon reflection through the refractive index of the metal.

[0078] More specifically, the phase change upon reflection of the metal part of the specimen can be theoretically calculated using the Fresnel equation below through the refractive index of the metal, and in the embodiment of the present invention, phase compensation is achieved through this.

[0079] [Mathematical Formula 1]

[0080]

[0081] In the above mathematical formula 1, n1 is the refractive index of air and n2 is the refractive index of metal.

[0082] Since n2 is a complex number, R metal Since the phase affects the measurement results and causes phase changes, surface shape measurement is possible by calculating and compensating for the phase.

[0083]

[0084] Meanwhile, regarding thin film structures, since the phase measured by the interferometer changes depending on the thickness of the film, the thickness must be measured to compensate for the phase change.

[0085] In an embodiment of the present invention, based on the refractive index of the thin film material and thin film theory, phase changes caused by the thin film are removed from the measurement results to measure only the surface shape of the thin film structure.

[0086] To this end, a wavelength at which phase changes caused by the thin film structure are eliminated is selected, and the phase is extracted through this.

[0087] The mathematical expression for this is the following mathematical formula 2.

[0088] [Mathematical Formula 2]

[0089]

[0090] In the above mathematical formula 2, r 12 r is the reflection coefficient at the boundary between air and the thin film. 23 n is the reflection coefficient at the boundary between the thin film and the base, n2 is the refractive index of the thin film, and d is the thickness of the thin film.

[0091] The phase measured in the thin film structure is the reflection coefficient R in the thin film in addition to the phase corresponding to the surface. film It changes due to.

[0092] Mathematical Equation 2 represents a single-layer thin film structure for a simple mathematical expression of a thin film structure.

[0093] In fact, in cases where the process is relatively stable, such as in semiconductors and displays, there is almost no difference in the refractive index of the material depending on the position of the specimen.

[0094] On the other hand, since thin films are generally composed of transparent dielectrics, their refractive index is real, and r 12 is a mistake.

[0095] However, the base layer usually uses silicon, and in this case, r 23 becomes a complex number, and as a result, R film is a complex number.

[0096] R film Since is a complex number, R film The phase of affects the measurement results and eventually causes a phase change.

[0097] At this time, R film Calculate the phase of R film If the condition for =0 is determined, it is equal to the following mathematical formula 3.

[0098] [Mathematical Formula 3]

[0099]

[0100] The above ∠r 23 This is the amount of phase change upon reflection at the boundary between the thin film and the base.

[0101] In mathematical equation 3 above, 2kn2d and ∠r 23 Since all of these are functions of wavelength, if a wavelength satisfying the above equation is selected and measured, the phase change occurring in the thin film structure can be eliminated.

[0102] The wavelength of light required to eliminate the phase change of the thin film structure is R film You can select through.

[0103] If mathematical equation 3 is satisfied, R film Since it has a minimum value mathematically, the wavelength can be selected through this.

[0104] Figure 5 is a simulation of the actual measurement process using a white light scanning interferometer. Figure 6 shows an example of data measured according to an embodiment of the present invention.

[0105] In the measurement, the white light scanning interferometer acquires interference signals from the metal surface and interference signals from the thin film structure.

[0106] When a Fourier transform is performed to analyze this in the frequency domain, peak signals can be obtained in the frequency domain, and as can be seen in Figure 5, in the case of a thin film structure, the signal is distorted due to [the element].

[0107] At this time, R film The wavelength corresponding to the minimum value at is extracted, and the corresponding phase is measured on the thin film structure and the metal surface.

[0108] Afterwards, if the phase change during reflection occurring on the metal surface is compensated based on Equation 1, only the surface shape of the thin film structure can be measured.

[0109] The above example is an example of a white light scanning interferometer, and the same principle can be used to measure only the surface shape of a specimen in interferometers with different structures and principles, such as dispersion interferometers, phase shift interferometers, and wavelength scanning interferometers.

[0110]

[0111] That is, the method for extracting the surface shape of a thin film structure according to an embodiment of the present invention measures an interference signal by irradiating light onto the surface of the thin film structure through an interferometer. Then, a wavelength selection unit selects a wavelength of light to eliminate phase changes of the thin film structure. An analysis unit extracts the selected wavelength, measures phase information at that wavelength, and analyzes the surface shape information of the thin film structure.

[0112] In the step of measuring these interference signals, interference signals for the metal part and the thin film structure part are acquired respectively (left side of Fig. 5).

[0113] And in the step of selecting the wavelength, a specific wavelength is selected such that the phase change in the thin film structure is minimized.

[0114] Specifically, the interference signal of the metal and the interference signal of the thin film structure are Fourier transformed (right side of Fig. 5).

[0115] Then, Gaussian fitting is performed on the FFT signal of the thin film structure to obtain an FFT signal with the Gaussian component removed.

[0116] Then, the wavelength selection unit selects the wavelength of the minimum value in the FFT signal from which the Gaussian component has been removed as a specific wavelength. This specific wavelength corresponds to the wavelength that satisfies the condition in Equation 3 in Equation 2 mentioned earlier.

[0117] And in the analysis step, the phase signal of the thin film structure at these specific wavelengths is measured.

[0118] In addition, the surface shape information of a thin film structure containing heterogeneous materials is analyzed by compensating for the phase change during reflection through Equation 1 using the refractive index of the metal.

[0119]

[0120] In addition, the apparatus and method described above are not limited to the configurations and methods of the embodiments described above; rather, all or part of each embodiment may be selectively combined to allow for various modifications to be made.

Claims

1. A surface shape extraction system for a thin-film structure using an interferometer that incidents light onto the interferometer, reflects it off a measurement target and a reference plane respectively, and acquires the interfered light through a camera, wherein A wavelength selection unit for selecting a wavelength of light to eliminate phase change of the above-mentioned thin film structure; An interferometer that measures an interference signal by irradiating light onto the surface of a thin film structure; and A surface shape extraction system for a thin film structure characterized by including an analysis unit that extracts a selected wavelength and measures the phase at the wavelength to analyze the surface shape of the thin film structure.

2. In Paragraph 1, A surface shape extraction system for a thin film structure, characterized in that the above-described thin film structure is a thin film structure including the above-described heterogeneous material, and includes a metal and a thin film structure.

3. In Paragraph 2, The above interferometer acquires interference signals for each of the metal and the thin film structure, and The wavelength selection unit selects a specific wavelength at which the phase change in the thin film structure is minimized, and The above analysis unit is, A surface shape extraction system for a thin film structure characterized by measuring the phase signal of the thin film structure at the above-mentioned specific wavelength and compensating for the phase change upon reflection through the refractive index of the above-mentioned metal to analyze the surface shape information of the thin film structure including the above-mentioned heterogeneous material.

4. In Paragraph 3, A surface shape extraction system for a thin film structure characterized in that the phase change upon reflection through the refractive index of the above metal is expressed by the following mathematical formula 1: [Mathematical Formula 1] In the above mathematical formula 1, n1 is the refractive index of air and n2 is the refractive index of metal.

5. In Paragraph 4, The phase change in the above thin film structure is expressed by the following Equation 2, and the wavelength selector is R film Surface shape extraction system for thin film structures characterized by selecting the wavelength at which this is minimized: [Mathematical Formula 2] In the above mathematical formula 2, r 12 r is the reflection coefficient at the boundary between air and the thin film. 23 n is the reflection coefficient at the boundary between the thin film and the base, n2 is the refractive index of the thin film, and d is the thickness of the thin film.

6. In Paragraph 5, The above R film A surface shape extraction system for a thin film structure characterized by the condition where =0 is expressed by the following mathematical formula 3: [Mathematical Formula 3] The above ∠r 23 This is the amount of phase change upon reflection at the boundary between the thin film and the base.

7. In Paragraph 3, The interference signal of the metal and the interference signal of the thin film structure are Fourier transformed, and Gaussian fitting is performed on the FFT signal of the thin film structure to obtain an FFT signal with the Gaussian component removed. A surface shape extraction system for a thin film structure characterized by a wavelength selection unit selecting the wavelength of the minimum value in the FFT signal from which the Gaussian component has been removed as the specific wavelength.

8. In Paragraph 1, A surface shape extraction system for a thin film structure, characterized in that the above interferometer is at least one of a white light scanning interferometer, a dispersion interferometer, a phase shift interferometer, and a wavelength scanning interferometer.

9. A method for extracting the surface shape of a thin film structure using an interferometer, wherein light is incident on the interferometer, reflected off the object to be measured and the reference plane respectively, and the interfered light is acquired through a camera, A step of measuring an interference signal by irradiating light onto the surface of a thin film structure through an interferometer; A step in which a wavelength selection unit selects a wavelength of light to eliminate a phase change of the thin film structure; A method for extracting the surface shape of a thin film structure, characterized by including the step of an analysis unit extracting a selected wavelength, measuring phase information at the wavelength, and analyzing the surface shape information of the thin film structure.

10. In Paragraph 9, The above thin film structure is a thin film structure including the above heterogeneous material, comprising a metal and a thin film structure, and In the step of measuring the interference signal, an interference signal for each of the metal and the thin film structure is obtained, and In the step of selecting the above wavelength, a specific wavelength is selected such that the phase change in the thin film structure is minimized, and A method for extracting the surface shape of a thin film structure, characterized in that, in the above-described analysis step, the phase signal of the thin film structure at the above-described specific wavelength is measured, and the phase change upon reflection is compensated through the refractive index of the metal to analyze the surface shape information of the thin film structure including the above-described heterogeneous material.

11. In Paragraph 10, A step of performing a Fourier transform on the interference signal of the metal and the interference signal of the thin film structure; A step of obtaining an FFT signal with Gaussian components removed by performing Gaussian fitting on the FFT signal of the thin film structure; and A method for extracting the surface shape of a thin film structure, characterized by including the step of the wavelength selection unit selecting the wavelength of the minimum value in the FFT signal from which the Gaussian component has been removed as the specific wavelength.

12. In Paragraph 10, A method for extracting the surface shape of a thin film structure, characterized in that the phase change upon reflection through the refractive index of the above metal is expressed by the following mathematical formula 1: [Mathematical Formula 1] In the above mathematical formula 1, n1 is the refractive index of air and n2 is the refractive index of metal.

13. In Paragraph 12, The phase change in the above thin film structure is expressed by the following Equation 2, and the wavelength selector is R film A method for extracting the surface shape of a thin film structure characterized by selecting the wavelength at which this is minimized: [Mathematical Formula 2] In the above mathematical formula 2, r 12 r is the reflection coefficient at the boundary between air and the thin film. 23 n is the reflection coefficient at the boundary between the thin film and the base, n2 is the refractive index of the thin film, and d is the thickness of the thin film.

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