TW201736798A - Film thickness measurement device for optical thin film having extremely high precision in static detection and dynamic detection and directly used on the production line - Google Patents

Abstract

A film thickness measurement device for an optical thin film includes a carrier, a light source, a condenser lens, and a spectrometer. The carrier is used to carry an optical thin film, and has a light incident port and a light exit port located at two opposite sides of the optical thin film and oppositely spaced from each other. The light source is located at one side of the light incident port of the carrier. The condenser lens is located between the light source and the optical thin film for condensing light beam of the light source and emitting it to the optical thin film. The spectrometer is located at one side of the light exit port for detecting a light signal passing through the optical thin film. The spectrometer can absorb a light signal with a wavelength of 200 nm ~ 850 nm. The present invention is a penetrative measurement device, which is not easily affected by a shock in the surrounding environment and has extremely high precision in static detection and dynamic detection. Therefore, the present invention can directly perform on-line detection on the production line.

Description

Film thickness measuring device for optical film

The present invention relates to a film thickness measuring device for a film, and more particularly to a measuring device for measuring the thickness of a transparent conductive oxide film.

Transparent conductive films are widely used in optoelectronics, semiconductors, biomedical and other fields, and their applications include mobile phones, tablets, displays, light-emitting diodes, solar cells, and so on. The transparency, conductivity, and uniformity of the transparent conductive film have a great influence on the performance of the product. Therefore, after the film is formed, it is necessary to conduct research and analysis on the above characteristics, and the film thickness is also one of the items to be tested.

A film thickness device or a method for detecting a transparent conductive film is known. For example, in the patent of Taiwan Patent No. 428079, the intensity of the reflected light is measured by an optical interference method to obtain a film thickness. Taiwan Patent No. 201420993 also uses optical interference method to measure the surface profile or thickness information of the surface of the film to be tested. In addition, X-rays, laser ultrasonic waves, and the like are used to detect the film thickness, and for the metal film, the film thickness can be measured by detecting the change of the eddy current. However, no matter which of the above measuring devices and methods, it is necessary to perform static detection under stable conditions without moving the film, because many of them are detected by interference of light, and if there is any vibration, the influence on the detection accuracy is large. As a result, the above detection device cannot be applied to a production line or a machine that can vibrate.

Accordingly, it is an object of the present invention to provide a film thickness measuring device suitable for static and dynamic detection, which has an optical film having high detection accuracy.

Thus, the film thickness measuring device of the optical film of the present invention is used for measuring the thickness of an optical film, and comprises a stage, a light source, a collecting lens, and a spectrometer. The stage is configured to carry the optical film, and has an optical entrance and a light exit opening on opposite sides of the optical film and opposite to each other. The light source is located on the side of the light entrance of the stage. The concentrating lens is located between the light source and the optical film, and is used for concentrating the light of the light source and then illuminating the optical film. The spectrometer is located on the side of the light exit of the stage for detecting an optical signal passing through the optical film, and the spectrometer can absorb optical signals having a wavelength of 200 nm to 850 nm.

The effect of the invention is that the spectrometer can detect the light passing through the optical film by the optical entrance and the light exit opening on opposite sides of the optical film, which is a transmissive measuring device. It is not easy to be affected by the surrounding environmental vibration. It has high precision in both static and dynamic detection, so it can be directly tested on the production line. Moreover, the concentrating effect of the concentrating lens can improve the collimation of the light of the light source and enhance the amount of light entering the optical film, which contributes to the absorption and lifting detection accuracy of the optical film. The spectrometer can perform spectral signal analysis for specific bands and also helps improve detection accuracy.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 1 and FIG. 2, a first embodiment of a film thickness measuring device for an optical film of the present invention is used for measuring the thickness of an optical film 1. The optical film 1 of the present embodiment is transparent to absorb ultraviolet light. Conductive oxide film. The film thickness measuring device comprises: a stage 2, a light source 3, a collecting lens 4, a filter 5, and a spectrometer 6.

The stage 2 is configured to carry the optical film 1 and includes a mounting portion 21 and a base portion 22 spaced apart from each other, a frame portion 23 between the base portion 22 and the mounting portion 21, and a bottom portion The base portion 22, the connecting portion 21 and the connecting portion 24 on the side of the frame portion 23 are extended and connected. The mounting portion 21 has a light entrance opening 211 extending from a top surface thereof toward a bottom surface thereof. The base portion 22 has a base wall 221 for the optical film 1 to be placed, and two side walls 222 extending downward from opposite sides of the base wall 221 and defining an accommodation space 220 together with the base wall 221. The base wall 221 has a light exit opening 223 extending from the top surface thereof toward the bottom surface thereof and communicating with the receiving space 220. The light entrance 211 and the light exit opening 223 are located on opposite sides of the optical film 1 and are spaced apart from each other.

The light source 3 is located on the side of the light entrance 211 of the stage 2, and the light of the light source 3 can be directed to the optical film 1 via the light entrance 211. The light source 3 is, for example, a halogen lamp.

The condensing lens 4 is located between the light source 3 and the optical film 1 and is used to condense the light of the light source 3 and then illuminate the optical film 1. In the present embodiment, the condensing lens 4 is a convex lens having a condensing function and is mounted on the frame portion 23 of the stage 2.

The filter 5 is located between the condensing lens 4 and the light source 3, and is fixed to the bottom surface of the mounting portion 21 of the stage 2 by a screw lock, and is located below the light entrance 211. The filter 5 of the present embodiment can be used to filter out light having a wavelength other than 200 nm to 400 nm.

The spectrometer 6 is disposed in the accommodating space 220 of the stage 2 and is located on the side of the light exit port 223 of the stage 2 for detecting the optical signal passing through the optical film 1. The spectrometer 6 can absorb optical signals having a wavelength of 200 nm to 850 nm. The detection principle applied in this embodiment is that the optical film 1 is a film capable of absorbing ultraviolet light, but not the entire ultraviolet light band is completely absorbed, but different absorption effects for different wavelengths of ultraviolet light, and The thickness of the film is different, and the effect of the optical film 1 on absorbing ultraviolet light is also different. Therefore, the thickness of the optical film 1 can be obtained by analyzing the contrast spectrum of the light passing through the optical film 1 and calculating, comparing and analyzing it through a computing module (for example, a computer) at the back end. Further, the optical film 1 of the present embodiment is, for example, an ITO transparent conductive film, and the spectrometer 6 can analyze the thickness of the optical film 1 by taking an optical signal having a wavelength of 320 nm to 400 nm. It should be noted that if the optical film 1 to be measured is an energy-saving film capable of shielding infrared rays, the spectrometer 6 can take an optical signal of 750 nm to 850 nm to analyze the film thickness of the energy-saving film. That is to say, the range of wavelengths to be analyzed by the spectrometer 6 can be adjusted with different kinds of optical films.

When the present invention is used, the light of the light source 3 passes through the light entrance port 211, and is filtered by the filter 5 to retain light of a specific wavelength. In this embodiment, the light having a wavelength of 200 nm to 400 nm is mainly filtered out. Light having a wavelength of 200 nm to 400 nm can be passed. The light passing through the filter 5 is further condensed by the condensing lens 4, and then incident on the optical film 1. The optical film 1, for example, an ITO transparent conductive film, can be deposited on a glass substrate by vacuum coating. The optical film 1 has the property of absorbing ultraviolet light, and the optical signal of the penetration spectrum of the optical film 1 is subsequently detected by the spectrometer 6, and the thickness of the optical film 1 is obtained by analysis of a working computer at the back end.

Referring to FIGS. 1 to 3, FIG. 3 is a relationship between light transmittance and film thickness, which is obtained by correlating the light transmittance of the optical film 1 with the film thickness in advance to obtain film thickness and light transmittance. Regression formula. 3 is an example of an ITO film, showing the spectrometer 6 of the present invention using two different spectrometers and taking three different wavelength bands. The two spectrometers are ultraviolet/visible spectrophotometers (UV-VIS spectrometers). And the micro spectrometer, the three bands are 320~370nm, 330~400nm, and 350~380nm respectively. From the experimental results of FIG. 3, it is known that the film thickness obtained by the six experiments is consistent with the trend of light transmittance. It is also possible to verify that the spectrometer 6 of the present invention can employ various spectrometers known.

Referring to Figures 1, 2, and 4, further, in this embodiment, a plurality of ITO films of different film thicknesses are deposited by sputtering, and the film thicknesses are separately measured. Specifically, five ITO films of different film thicknesses are formed, and the film thickness of each sample is about 75 to 115 nm. The thickness of each optical film 1 can be measured by a Spectroscopic Ellipsometer (SE). To obtain accurate film thickness as a reference standard. The device of the present invention is then used for static and dynamic film thickness detection. The static film thickness detection is that the optical film 1 is statically placed on the base portion 22 of the stage 2, and then the film thickness measurement is performed by the apparatus and principle of the present invention, and the measurement errors of the five samples are The average of the absolute values was 0.87 nm with a standard deviation of 1.3 nm. When performing dynamic film thickness detection, the present invention is mainly installed on the side of a conveyor belt (not shown) of a production line, and the optical film 1 can be conveyed by the conveyor belt, and the height position of the conveyor belt and the optical film 1 is introduced. Between the light exit opening 223 and the collecting lens 4, film thickness detection is performed when the optical film 1 is transported through the apparatus of the present invention. Referring to Fig. 4, the results of the dynamic film thickness measurement by the film thickness measuring device of the present invention and the comparison of the film thickness by the spectral ellipsometer (labeled "SE measurement value" in Fig. 4) are shown, and the dynamic detection result is shown. The average of the measurement errors (absolute value average) of the five different thickness samples was 3.88 nm, and the standard deviation was 4.38 nm. It can be seen that the measurement error of the invention is small or static, and the measurement result has high precision.

In summary, the present invention is for measuring the film thickness of the optical film 1, in particular, the optical film 1 capable of absorbing ultraviolet rays, and the optical film 1 has different absorption characteristics with different thicknesses, so the present invention The light-injecting port 211 and the light-emitting port 223 are located on opposite sides of the optical film 1 so that the spectrometer 6 can detect light passing through the optical film 1, which is a transmissive measurement. The device is different from the device and principle generally measured by interferometry. Moreover, the penetrating detection method is less susceptible to the surrounding environmental vibration. It is also known from the above experimental results that the present invention has extremely high precision in both static detection and dynamic detection, so that on-line detection can be directly performed on the production line. Moreover, the light collecting effect of the condensing lens 4 can improve the collimation of the light of the light source 3, and increase the amount of light entering the optical film 1, which helps the optical film 1 to absorb and improve the detection accuracy. . The spectrometer 6 can perform spectral signal analysis for a specific wavelength band, avoid interference of other wavelengths of light, reduce noise, and also improve detection accuracy. Further, the filter 5 is designed such that only light of a specific wavelength range is incident on the optical film 1 through the filter 5, which can reduce interference of other light sources and help to improve measurement accuracy.

Referring to FIG. 5, a second embodiment of the film thickness measuring device of the optical film of the present invention is substantially the same as the structure of the first embodiment, except that the film thickness measuring device of the embodiment further includes a A first optical fiber 7 between the light source 3 and the light entrance port 211, and a second optical fiber 8 between the spectrometer 6 and the light exit port 223. The first optical fiber 7 concentrates the light of the light source 3 to the light entrance 211, and passes the collimated and high-brightness light through the filter 5 and the condensing lens 4 to the optical film 1. The second optical fiber 8 concentrates the light passing through the optical film 1 to the spectrometer 6.

In this embodiment, through the excellent light-conducting effect of the first optical fiber 7 and the second optical fiber 8, the light of the light source 3 can be concentrated and efficiently transmitted to the optical film 1, and the light passing through the optical film 1 is also penetrated. It can be concentrated and efficiently transmitted to the spectrometer 6, so that the optical signal detected by the spectrometer 6 is good in quality, low in noise and strong in intensity, thereby improving detection accuracy.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

1‧‧‧Optical film
2‧‧‧ stage
21‧‧‧Installation Department
211‧‧‧Into the light port
22‧‧‧ base
220‧‧‧ accommodating space
221‧‧‧ base wall
222‧‧‧ side wall
223‧‧‧Light outlet
23‧‧‧‧
24‧‧‧Connecting Department
3‧‧‧Light source
4‧‧‧ Concentrating lens
5‧‧‧ filter
6‧‧‧ Spectrometer
7‧‧‧First fiber
8‧‧‧second fiber

Other features and effects of the present invention will be apparent from the following description of the drawings. FIG. 1 is an exploded perspective view showing a first embodiment of the film thickness measuring device of the optical film of the present invention; Figure 2 is a combined side view of the first embodiment; Figure 3 is a graph showing the relationship between the light transmittance of the ITO film and the film thickness; Figure 4 is a comparison of the film thicknesses, showing the use of the present invention and the spectral ellipsometer The measurement results of five different thickness optical films are measured; and FIG. 5 is a combined side view showing a second embodiment of the film thickness measuring device of the optical film of the present invention.

2‧‧‧ stage

21‧‧‧Installation Department

211‧‧‧Into the light port

22‧‧‧ base

220‧‧‧ accommodating space

221‧‧‧ base wall

222‧‧‧ side wall

223‧‧‧Light outlet

23‧‧‧‧

24‧‧‧Connecting Department

3‧‧‧Light source

4‧‧‧ Concentrating lens

5‧‧‧ filter

6‧‧‧ Spectrometer

Claims (7)

An optical film thickness measuring device for measuring the thickness of an optical film, and comprising: a stage for carrying the optical film, and having opposite sides on opposite sides of the optical film a light source and a light exit port; a light source located on the light entrance side of the stage; a collecting lens located between the light source and the optical film for collecting the light of the light source and then directing The optical film; and a spectrometer located on the light exit side of the stage for detecting an optical signal passing through the optical film, the spectrometer capable of absorbing optical signals having a wavelength of 200 nm to 850 nm. The film thickness measuring device of the optical film of claim 1, further comprising a first optical fiber between the light source and the light entrance port, the first optical fiber guiding the light of the light source to the light entrance port, Light is passed through the concentrating lens and directed toward the optical film. The film thickness measuring device for an optical film according to claim 2, further comprising a second optical fiber between the spectrometer and the light exit port, the second optical fiber guiding light passing through the optical film to the spectrometer. The film thickness measuring device for an optical film according to claim 1, further comprising a filter between the optical film and the light source, wherein the filter filters out light having a wavelength of from 200 nm to 400 nm. The film thickness measuring device for an optical film according to claim 4, wherein the filter is located between the collecting lens and the light source. The film thickness measuring device for an optical film according to any one of claims 1 to 5, wherein the optical film is a transparent conductive oxide film capable of absorbing ultraviolet light. The film thickness measuring device for an optical film according to claim 6, wherein the spectrometer is obtained by taking an optical signal having a wavelength of 320 nm to 400 nm to analyze the thickness of the optical film.