TWI872727B - Surface topography measuring device - Google Patents

Abstract

A surface topography measuring device is suitable for measuring an object to be detected and includes a light source system, a light splitting assembly, a phase difference film and a phase resolution system. The light source system provides a beam. The light splitting assembly is arranged on one side of the light source system. The phase difference film is arranged between the light splitting assembly and the object. The phase resolution system is set on one side of the light splitting assembly. The beam is converted into a reflected beam and a penetrating beam. The penetrating beam is transmitted to the object after passing through the phase difference film, reflected by the object, passed through the phase difference film, and interferes with the reflected beam to form an interference beam. The interference beam is transmitted to the phase resolution system and analyzed to obtain a surface topography of the object.

Description

Surface topography measurement device

The present invention relates to a measuring device, and in particular to a surface morphology measuring device.

As the industrial development becomes more and more precise, the requirements for surface properties including surface morphology, electrical properties, magnetic properties, mechanical properties, etc. have also been raised to the micron, nanometer, and even atomic levels, so the need to measure surface properties has arisen. Among surface properties, surface morphology measurement can be roughly divided into three categories: probe type, optical interferometry, and scanning probe type. Optical interferometry is becoming more and more popular compared to the other two measurement methods because it can directly measure the full-field morphology of the specimen, does not contact the specimen and therefore does not cause damage to the specimen, and has an accuracy of nanometers.

Among existing optical interferometric surface topography measurement methods, the commonly used phase-shifting technology uses interference fringe images with different phase values for analysis, which has the advantages of fast and accurate analysis. However, it is known that a high-precision moving platform is required to push the specimen during the measurement process. The above-mentioned moving process is relatively time-consuming, thus prolonging the measurement time, and the high-precision moving platform equipment is expensive.

It is known that the surface topography measurement method using optical interferometry has the disadvantages of slow measurement speed and high equipment cost. Therefore, it is necessary to develop a surface topography measurement device with fast measurement speed and low equipment cost.

The surface morphology measuring device provided by the present invention is suitable for measuring the surface morphology of an object to be detected. The surface morphology measuring device includes a light source system, a spectroscopic component, a phase difference film and a phase separation system, wherein the light source system is suitable for providing a light beam. The spectroscopic component is arranged on one side of the light source system. The phase difference film is arranged between the spectroscopic component and the object to be detected. The phase separation system is arranged on one side of the spectroscopic component. The light beam provided by the light source system is suitable for being converted into a reflected light beam and a transmitted light beam through the spectroscopic component. The transmitted light beam is suitable for being transmitted to the object to be detected after the first phase delay through the phase difference film, and is suitable for being reflected by the object to be detected, and then being transmitted to the spectroscopic component after the second phase delay through the phase difference film again. The transmitted light beam after the first phase delay and the second phase delay passes through the spectroscopic component and interferes with the reflected light beam to form an interference light beam. The interference light beam is transmitted to the phase separation system through the spectroscopic component. The phase separation system is suitable for analyzing the interference light beam and obtaining the surface morphology of the object to be detected.

In one embodiment of the present invention, the above-mentioned spectroscopic component includes a first spectroscopic element and a second spectroscopic element, the first spectroscopic element is arranged between the light source system and the second spectroscopic element, the second spectroscopic element is arranged between the first spectroscopic element and the phase difference film, and the phase difference film is arranged between the second spectroscopic element and the object to be detected.

In one embodiment of the present invention, the above-mentioned light beam is suitable for passing through the first beam splitter and transmitted to the second beam splitter, and is converted into a reflected light beam and a transmitted light beam by the second beam splitter. After the transmitted light beam completes the second phase delay, it is transmitted to the second beam splitter, and then the interference light beam is transmitted to the dephasing system through the first beam splitter.

In one embodiment of the present invention, the surface morphology measuring device further includes a beam expansion component, which includes a filter, a first lens and a second lens, wherein the filter is disposed between the light source system and the first beam splitter, the first lens is disposed between the first beam splitter and the second beam splitter, and the second lens is disposed between the first beam splitter and the dephasing system and is located on the transmission path of the interference beam.

In one embodiment of the present invention, the above-mentioned filter is a spatial filter.

In one embodiment of the present invention, the surface topography measurement device further includes a beam expansion assembly, which includes a first lens and a second lens, wherein the first lens is disposed between the light source and the first beam splitter, and the second lens is disposed between the first lens and the first beam splitter.

In one embodiment of the present invention, the above-mentioned light source system includes a laser light source suitable for providing a light beam.

In one embodiment of the present invention, the above-mentioned light source system further includes a linear polarizer disposed between the laser light source and the spectroscopic component.

In one embodiment of the present invention, the above-mentioned dephasing system includes a wave plate and a polarization camera, wherein the polarization camera is suitable for capturing four polarization states of the interfering light beam.

In one embodiment of the present invention, the wave plate mentioned above is a quarter wave plate.

The present invention uses a phase difference film to delay the penetrating light beam, so that the phase difference between the reflected light beam and the penetrating light beam is different, and a phase resolution system is used to capture interference fringe images of different polarization states. Therefore, during the measurement process, it is not necessary to use expensive equipment to move the object to be tested, thereby improving the measurement speed and reducing the equipment cost.

In order to make the above and other purposes, features and advantages of the present invention more clearly understood, the following is a detailed description of the embodiments with the accompanying drawings.

100, 100a: surface morphology measurement device

110: Light source system

111:Laser light source

112: Linear polarizer

120: Spectroscopic component

121: First spectroscopic element

122: Second spectroscopic element

130: Phase difference film

140: Phase Decomposition System

141: Wave plate

142: Polarization camera

150, 150a: expansion assembly

151, 151a: First lens

152, 152a: Second lens

153:Filter

200: Object to be tested

H: Surface morphology

L: beam

L1: reflected beam

L2, L2', I2": penetrating beam

M: Reflector

Figure 1 is a schematic diagram of the configuration of a surface morphology measurement device according to an embodiment of the present invention.

Figure 2 is a schematic diagram of the configuration of a surface morphology measurement device of another embodiment of the present invention.

FIG1 is a schematic diagram of the configuration of a surface morphology measuring device of an embodiment of the present invention. Referring to FIG1 , the surface morphology measuring device 100 of the present embodiment is suitable for measuring the surface morphology of an object to be detected 200. The surface morphology measuring device 100 includes a light source system 110, a spectroscopic component 120, a phase difference film 130 and a phase separation system 140, wherein the light source system 110 is suitable for providing a light beam L. The spectroscopic component 120 is arranged on one side of the light source system 110. The phase difference film 130 is arranged between the spectroscopic component 120 and the object to be detected 200. The phase separation system 140 is arranged on one side of the spectroscopic component 120. The light beam L provided by the light source system 110 is suitable for being converted into a reflected light beam L1 and a transmitted light beam L2 through the spectroscopic component 120. The transmitted light beam L2 is suitable for being transmitted to the object to be detected 200 after a first phase delay through the phase difference film 130, and is suitable for being reflected by the object to be detected 200 and then being transmitted to the spectroscopic component 120 after a second phase delay through the phase difference film 130 again. The transmitted light beam L2" after the first phase delay and the second phase delay passes through the spectroscopic component 120 and interferes with the reflected light beam L1 to form an interference light beam _Li (that is, L2" and L1 interfere to form _Li ). The interference light beam _Li is transmitted to the dephasing system 140 through the spectroscopic component 120. The dephasing system 140 is suitable for analyzing the interference light beam _Li and obtaining the surface morphology H of the object to be detected 200.

Specifically, the light beam L provided by the light source system 110 of the surface morphology measuring device 100 of the present embodiment is linearly polarized light. When the light beam L passes through the spectroscopic component 120, it is converted into a reflected light beam L1 and a transmitted light beam L2, wherein the reflected light beam L1 is transmitted to the dephasing system 140 after being reflected from the spectroscopic component 120, and the transmitted light beam L2 is suitable for passing through the phase difference film 130 for the first phase delay after passing through the spectroscopic component 120, thereby forming a transmitted light beam L2' after the first phase delay. The penetrating light beam L2' is transmitted to the surface of the object to be detected 200 and then reflected. At this time, the information of the surface morphology H of the object to be detected 200 is formed in the penetrating light beam L2' reflected by the object to be detected 200. Then, the penetrating light beam L2' passes through the phase difference film 130 again for a second phase delay to form the penetrating light beam L2". That is, compared with the reflected light beam L1, the penetrating light beam L2" passes through the phase difference film 130 twice and is reflected by the object to be detected 200. Therefore, the penetrating light beam L2" not only has a different phase difference from the reflected light beam L1, but also carries the information of the surface morphology H of the object to be detected 200 (that is, the object to be detected 200 changes the phase of the penetrating light beam L2". Continuing from the above, the penetrating light beam L2" passes through the spectroscopic component 120 and interferes with the reflected light beam L1 reflected by the spectroscopic component 120 to form an interference light beam L _i . The interference light beam L _i is then transmitted to the dephasing system 140 via the spectroscopic component 120.

On the other hand, the phase difference film 130 of the present embodiment is, for example, a quarter wave plate, so that the light passing through the phase difference film 130 will be delayed by 45° in phase, so the penetrating light beam L2" that has undergone two phase delays will be delayed by 90° in phase due to the phase difference film 130. It should be noted that since there is a phase difference between the penetrating light beam L2" and the reflected light beam L1, the information of the surface morphology H of the object to be detected 200 will be formed in the phase of the interference light beam _Li , so that the surface morphology measuring device 100 of the present embodiment can analyze the phase introduced by the object to be detected 200 through the phase analyzer 140 to obtain the surface morphology H of the object to be detected 200.

，其中

，上述α為解相系統140的偏振方向，

為待檢測物200引入的相位，其中本實施例中的解相系統140的偏振方向例如有4個，例如分別為0°、45°、90°和135°。接著經由解相方程式

求得相位差分布

，再將上述計算求得的

帶入

方程式中即可求得待檢測物200的表面形貌H的資訊，上述λ為光束的波長，h(x,y)為待檢測物200表面各點的相對高度，亦即表面形貌H。 Specifically, the dephasing system 140 is adapted to capture the light intensity of the interference light beam _Li

,in

, the above α is the polarization direction of the dephasing system 140,

is the phase introduced by the object to be detected 200, wherein the polarization directions of the phase solver 140 in this embodiment are, for example, 4, such as 0°, 45°, 90° and 135°. Then, by solving the phase equation

Obtain phase difference distribution

, and then the above calculation obtained

Bring in

The information of the surface morphology H of the object to be detected 200 can be obtained from the equation. The above λ is the wavelength of the light beam, and h (x, y) is the relative height of each point on the surface of the object to be detected 200, that is, the surface morphology H.

In the surface topography measuring device 100 of the present embodiment, the phase difference film 130 is used to phase-delay the penetrating light beam L2, so that the phase difference between the reflected light beam L1 and the penetrating light beam L2" after two phase delays is different, and the phase separation system 140 is used to capture the interference fringe images of the interference light beam _Li in different polarization states. In the measurement process, it is not necessary to use expensive equipment to move the object to be tested 200, thereby improving the measurement speed and reducing the equipment cost.

Continuing with FIG. 1 , the light source system 110 of the present embodiment includes, for example, a laser light source 111 and a linear polarizer 112, and the laser light source 111 is suitable for providing a light beam L. The linear polarizer 112 is, for example, disposed between the laser light source 111 and the beam splitter 120, so that the light beam L provided by the laser light source 111 becomes a linearly polarized light, but the present invention is not limited thereto. In another embodiment, the light source system 110 can directly provide a linearly polarized light beam L. The light source system 110 of the present embodiment further includes, for example, a reflector M disposed between the laser light source 111 and the linear polarizer 112, but the present invention is not specifically limited thereto. In addition, the dephasing system 140 of the present embodiment includes, for example, a wave plate 141 and a polarization camera 142, wherein the polarization camera 142 is suitable for capturing four polarization states of the interference light beam _Li , and the wave plate 141 is, for example, a quarter wave plate, but the present invention is not limited thereto. The four polarization states captured by the polarization camera 142 are, for example, polarization states of the interference light beam _Li at 0°, 45°, 90°, and 135°, respectively, but the present invention is not specifically limited thereto.

Please continue to refer to FIG. 1 . The spectroscopic assembly 120 of the present embodiment includes, for example, a first spectroscopic element 121 and a second spectroscopic element 122. The first spectroscopic element 121 is, for example, disposed between the light source system 110 and the second spectroscopic element 122. The second spectroscopic element 122 is, for example, disposed between the first spectroscopic element 121 and a phase difference film 130. The phase difference film 130 is, for example, disposed between the second spectroscopic element 122 and the object to be detected 200. The light beam L of the present embodiment is adapted to pass through the first spectroscopic element 121 and be transmitted to the second spectroscopic element 122, and is converted into a reflected light beam L1 and a transmitted light beam L2 by the second spectroscopic element 122. When the transmitted light beam L2" completes the second phase delay, it is transmitted to the second spectroscopic element 122, and then the interference light beam _L1 is transmitted to the dephasing system 140 via the first spectroscopic element 121.

Specifically, the first beam splitter 121 of this embodiment allows the light beam L to pass through and be transmitted to the second beam splitter 122, and allows the interference light beam _Li to be transmitted to the dephasing system 140 via the first beam splitter 121. The first beam splitter 121 can be a spectroscope, but the present invention is not specifically limited thereto. The second beam splitter 122 of the present embodiment is mainly used to convert the light beam L into a reflected light beam L1 and a transmitted light beam L2, and is suitable for allowing the transmitted light beam L2' to pass through. The above-mentioned second beam splitter 122 is, for example, a semi-reflecting mirror, but the present invention is not limited thereto. It should be noted that in the present embodiment, the second beam splitter 122 and the phase difference film 130 are, for example, separated, but the present invention does not make specific limitations on this. In another embodiment of the present invention, the second beam splitter 122 and the phase difference film 130 can be bonded together (not shown in the figure), and at this time, the transmission path of the light beam L is similar to that of FIG. 1, that is, after the light beam L is converted into the reflected light beam L1 and the transmitted light beam L2 by the second beam splitter 122, the transmitted light beam L2 immediately passes through the phase difference film 130 for the first phase delay to form the transmitted light beam L2', and the subsequent path is the same as FIG. 1, which will not be repeated here.

The surface topography measurement device 100 of the present embodiment may further include a beam expansion component 150, which includes, for example, a filter 153, a first lens 151, and a second lens 152, wherein the filter 153 is, for example, disposed between the light source system 110 and the first beam splitter 121, the first lens 151 is, for example, disposed between the first beam splitter 121 and the second beam splitter 122, and the second lens 152 is, for example, disposed between the first beam splitter 121 and the dephasing system 140 and located on the transmission path of the interference beam _Li . The filter 153 is, for example, a spatial filter, but the present invention is not specifically limited thereto. Specifically, by providing the filter 153 and the first lens 151, the light beam L is expanded, that is, the irradiation range of the light beam L is enlarged, so when the penetrating light beam L2' is transmitted to the object to be tested 200, it can irradiate the object to be tested 200 in a large range, which helps the surface topography measurement device 100 to analyze the surface topography H of multiple points in a large range. In addition, the second lens 152 in this embodiment can collimate the interference light beam _Li transmitted from the first beam splitter 121 to the dephasing system 140, but the present invention is not specifically limited to this.

FIG2 is a schematic diagram of the configuration of a surface topography measurement device according to another embodiment of the present invention. As shown in FIG2 , the second lens 152 shown in FIG1 may not be disposed between the first beam splitter element 121 and the phase separation system 140. In other words, in the embodiment shown in FIG2 , the beam expansion assembly 150a includes, for example, a first lens 151a and a second lens 152a, wherein the first lens 151a is, for example, disposed between the light source system 110 and the first beam splitter element 121, and the second lens 152a is, for example, disposed between the first lens 151a and the first beam splitter element 121. In detail, the present embodiment allows the light beam L to be expanded through the first lens 151a and the second lens 152a before passing through the first beam splitter 121. Therefore, when the light beam L is converted into the reflected light beam L1 and the transmitted light beam L2, and even the interference light beam L _i is formed and transmitted to the dephasing system 140, the reflected light beam L1, the transmitted light beams L2, L2', L2" and the interference light beam L _i will not be focused. Therefore, in this embodiment, there is no need to set an optical element (such as the element number 152 in Figure 1) in front of the dephasing system 140 to collimate the interference light beam L _i .

In summary, the present invention uses a phase difference film to delay the penetrating light beam, so that the phase difference between the reflected light beam and the penetrating light beam is different, and uses a phase separation system to capture interference fringe images of different polarization states. Therefore, during the measurement process, it is not necessary to use expensive equipment to move the object to be tested, thereby improving the measurement speed and reducing the equipment cost.

Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Those with common knowledge in the technical field to which the present invention belongs may make some changes and modifications within the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined in the attached patent application.

100: Surface morphology measurement device

110: Light source system

111:Laser light source

112: Linear polarizer

120: Spectroscopic component

121: First spectroscopic element

122: Second beam splitter element

130: Phase difference film

140: Phase Decomposition System

141: Wave plate

142: Polarization camera

150:Expansion component

151:First lens

152: Second lens

153:Filter

200: Object to be tested

H: Surface morphology

L: beam

L1: reflected beam

L2, L2', L2": Penetrating beam

_Li : Interference beam

M: Reflector

Claims (8)

A surface topography measuring device is suitable for measuring the surface topography of an object to be detected. The surface topography measuring device comprises: a light source system, suitable for providing a light beam; a spectroscopic component, arranged on one side of the light source system; a phase difference film, arranged between the spectroscopic component and the object to be detected; and a phase separation system, arranged on one side of the spectroscopic component, wherein the light beam provided by the light source system is suitable for being converted into a reflected light beam and a transmitted light beam by the spectroscopic component, and the transmitted light beam is suitable for After passing through the phase difference film for a first phase delay, the light beam is transmitted to the object to be detected, and after being reflected by the object to be detected, the light beam is transmitted to the spectroscopic component after passing through the phase difference film for a second phase delay. The transmitted light beam after the first phase delay and the second phase delay passes through the spectroscopic component and interferes with the reflected light beam to form an interference light beam. The interference light beam is transmitted to the phase separation system through the spectroscopic component. The phase separation system is suitable for analyzing the interference light beam and obtaining the object to be detected. a surface morphology of the object to be detected; the spectroscopic assembly includes a first spectroscopic element and a second spectroscopic element, the first spectroscopic element is arranged between the light source system and the second spectroscopic element, the second spectroscopic element is arranged between the first spectroscopic element and the phase difference film, the phase difference film is arranged between the second spectroscopic element and the object to be detected, wherein the light beam is suitable for passing through the first spectroscopic element and being transmitted to the second spectroscopic element, and is converted into the reflected light beam and the penetrating light beam by the second spectroscopic element The second beam splitter is a semi-reflecting mirror. The second beam splitter makes the converted reflected beam and the penetrating beam transmitted in opposite and parallel directions. After the penetrating beam completes the second phase delay, it is sequentially transmitted to the second beam splitter and the first beam splitter. After the second phase delay, the penetrating beam and the reflected beam are transmitted to the first beam splitter in the same direction. Then, the interference beam is transmitted to the phase separation system through the first beam splitter. The surface morphology measurement device as described in claim 1 further includes a beam expansion component, which includes: a filter disposed between the light source system and the first beam splitter; a first lens disposed between the first beam splitter and the second beam splitter; and a second lens disposed between the first beam splitter and the dephasing system and located on a transmission path of the interference light beam. A surface morphology measurement device as described in claim 2, wherein the filter is a spatial filter. The surface morphology measurement device as described in claim 1 further includes a beam expansion component, which includes: a first lens disposed between the light source system and the first beam splitter; and a second lens disposed between the first lens and the first beam splitter. A surface morphology measuring device as described in claim 1, wherein the light source system includes a laser light source suitable for providing the light beam. The surface morphology measuring device as described in claim 5, wherein the light source system further includes a linear polarizer disposed between the laser light source and the spectroscopic component. A surface morphology measurement device as described in claim 1, wherein the dephasing system includes a wave plate and a polarization camera, wherein the polarization camera is suitable for capturing the four polarization states of the interference light beam. A surface morphology measurement device as described in claim 7, wherein the wave plate is a quarter wave plate.

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