TWI753477B - System and method for monitoring optical thin film deposition - Google Patents

Abstract

A system for monitoring optical thin film deposition includes a coating machine for coating the optical thin film, a monochromatic real-time light intensity monitoring module, and a broadband wavelength real-time spectrum monitoring module. The monochromatic real-time light intensity monitoring module is configured to simultaneously calculate a refractive index and an extinction coefficient of the optical thin film at a wavelength during the coating process performed by the coating machine, thereby calculating a refractive index and an extinction coefficient of the optical thin film at each of different wavelengths according to the refractive index and the extinction coefficient of the optical thin film at the wavelength. The broadband wavelength real-time spectrum monitoring module is configured to calculate a current thickness according to the refractive index and the extinction coefficient of the optical thin film at each of different wavelengths, thereby determining whether a cut-point of the optical thin film is reached according to the current thickness.

Description

Monitoring system and method for producing optical film

The present invention relates to a monitoring system for producing optical films, and more particularly, to a monitoring system for producing optical films and a method thereof.

The effect of optical thin film coating depends on the accuracy of controlling the optical properties (such as refractive index, absorption coefficient, etc.) and film thickness of each layer of film in the coating. Currently, the monitoring methods generally used are: time monitoring, quartz oscillator monitoring , Single-wavelength optical monitoring and wide-wave domain optical monitoring. The disadvantage of time monitoring is that it cannot monitor the coating rate, refractive index, absorption coefficient and does not have the effect of compensating for the error of the front layer. The disadvantage of quartz oscillator monitoring is that it cannot monitor the refractive index, absorption coefficient and does not have the effect of compensating for the error of the front layer. The disadvantage of single-wavelength optical monitoring is the inability to handle the wider spectral shape. The disadvantage of wide-wave domain optical monitoring is the stable control of refractive index and absorption coefficient.

The purpose of the present disclosure is to provide a monitoring system for producing optical films, including a coating machine, a single-wavelength real-time light intensity monitoring module, and a wide-wave domain real-time spectrum monitoring module. Coating machines are used to coat optical films. The single-wavelength real-time light intensity monitoring module is used to calculate the refractive index and extinction coefficient of the optical film corresponding to a wavelength in real time during the process of coating the optical film by the coating mechanism, and then according to the refractive index and extinction of the optical film corresponding to the wavelength. The refractive index and extinction coefficient of the optical film corresponding to each wavelength are calculated by using the coefficients. The wide-wave domain real-time spectrum monitoring module is used to calculate the current thickness of the optical film according to the refractive index and extinction coefficient corresponding to each wavelength of the optical film, and judge whether the optical film has reached the stop point according to the current thickness.

In some embodiments, the single-wavelength real-time light intensity monitoring module includes a single-wavelength light source module with the wavelength and a light sensor, and the light sensor is used to measure the passage of the light beam emitted by the single-wavelength light source module The transmitted light intensity of the optical film, the single-wavelength real-time light intensity monitoring module is used to calculate at least one of the transmittance and the reflectance according to the transmitted light intensity, so as to calculate the optical film corresponding to the wavelength. Refractive index and extinction coefficient.

In some embodiments, the refractive index and the extinction coefficient of the optical film corresponding to each wavelength are calculated according to the refractive index and the extinction coefficient of the optical film corresponding to the wavelength through a proportional or equidistant manner.

In some embodiments, when the coating machine is used to coat the multilayer film stack, the wide-wave domain real-time spectrum monitoring module is further used to determine whether to modify the design thickness according to the current thickness of the current layer corresponding to the optical film.

In some embodiments, when it is determined that the design thickness needs to be corrected, the wide-wave domain real-time spectrum monitoring module is further configured to calculate the refractive index and extinction coefficient corresponding to each wavelength of the current layer corresponding to the optical film and the corresponding optical film The current thickness of the current film layer is used to modify the design thickness.

The purpose of the present disclosure is to further provide a monitoring method for producing a coating optical film, which includes: using a single-wavelength real-time light intensity monitoring module to instantly calculate the refractive index of the optical film corresponding to a wavelength and the Extinction coefficient, and then calculate the refractive index and extinction coefficient corresponding to each wavelength of the optical film according to the refractive index and extinction coefficient of the optical film at the wavelength; The current thickness of the optical film is calculated from the refractive index and extinction coefficient corresponding to each wavelength respectively; and whether the optical film has reached the stop point is determined according to the current thickness of the optical film.

In some embodiments, the single-wavelength real-time light intensity monitoring module includes a single-wavelength light source module with the wavelength and a light sensor, wherein the single-wavelength real-time light intensity monitoring module calculates the wavelength of the optical film at the wavelength The method for the corresponding refractive index and extinction coefficient includes: measuring the penetrating light intensity when the light beam emitted by the single-wavelength light source module passes through the optical film by a light sensor; calculating the penetrating rate according to the penetrating light intensity at least one of reflectance and transmittance; and calculating the refractive index and extinction coefficient of the optical film corresponding to the wavelength according to at least one of transmittance and reflectance.

In some embodiments, the refractive index and the extinction coefficient of the optical film corresponding to each wavelength are calculated according to the refractive index and the extinction coefficient of the optical film corresponding to the wavelength through a proportional or equidistant manner.

In some embodiments, the monitoring method for coating optical films further includes: when the coating machine is used to coat the multilayer film stack, judging whether to modify the design thickness according to the current thickness of the current layer corresponding to the optical film.

In some embodiments, the monitoring method for producing an optical film further comprises: when determining that the design thickness needs to be corrected, according to the refractive index and extinction coefficient corresponding to each wavelength of the current layer corresponding to the optical film and corresponding to the optical film The current thickness of the current film layer of the film is used to modify the design thickness.

In order to make the above-mentioned features and advantages of the present disclosure more obvious and easy to understand, the following embodiments are given and described in detail in conjunction with the accompanying drawings as follows.

Embodiments of the present invention are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable concepts that can be embodied in a wide variety of specific contexts. The discussed and disclosed embodiments are for illustration only, and are not intended to limit the scope of the present invention.

FIG. 1 is a schematic diagram of a monitoring system 100 for forming an optical film according to an embodiment of the present disclosure. The monitoring system 100 for producing optical films includes a coating machine 110 , a monochromatic real-time light intensity monitoring module 120 and a broad-wavelength (broadband wavelength) real-time spectrum monitoring module 130 . The coating machine 110 is used for coating the optical film 112 . The single-wavelength real-time light intensity monitoring module 120 and the wide-wave domain real-time spectrum monitoring module 130 are used to monitor the optical properties of the optical film 112 in real time during the process of coating the optical film 112 by the coating machine 110 , so as to control the growth of the optical film 112 changes in film thickness over time.

The single-wavelength real-time light intensity monitoring module 120 includes a single-wavelength light source module 122 and a light sensor 124. The single-wavelength light source module 122 is used to emit a light beam with a single wavelength (eg, 1000 nanometers (nm)), and the light sensing The device 124 is used to measure the transmitted light intensity when the light beam with a single wavelength passes through the optical film 112 . In the embodiment of the present disclosure, the single-wavelength real-time light intensity monitoring module 120 is used in the process of coating the optical film 112 by the coating machine 110 to measure according to the light sensor 124 every moment (for example, every second) The current transmittance and/or reflectance of the optical film 112 can be calculated based on the obtained transmitted light intensity.

In the embodiment of the present disclosure, the light sensor 124 may be, for example, a photodiode (PD) or a photomultiplier (PMT). In the embodiment of the present disclosure, the light sensor 124 can also be, for example, a real-time spectrometer. The real-time spectrometer is used to measure the transmission spectrum of a light beam with a single wavelength passing through the optical film 112 , and the single-wavelength real-time light intensity monitoring module 120 It is used to calculate the current transmittance and/or reflectivity of the optical film 112 according to the transmittance spectrum measured by the real-time spectrometer.

In the embodiment of the present disclosure, the single-wavelength real-time light intensity monitoring module 120 may further include other optical elements for modulating the light shape of the light beam with a single wavelength, and the other optical elements may be, for example, a light collimating element, a beam splitter , polarizer and/or imaging lens, etc., the composition and arrangement of these optical elements can be changed according to the actual implementation situation, and the present disclosure does not limit the composition and arrangement of these optical elements.

In the embodiment of the present disclosure, the single-wavelength real-time light intensity monitoring module 120 is further configured to calculate the refractive index of the optical film 112 corresponding to the single wavelength according to the current transmittance and/or reflectance of the optical film 112 and extinction coefficient. It is worth mentioning that the calculated refractive index and extinction coefficient of the optical film 112 corresponding to the single wavelength are analytical solutions obtained through real-time calculation and updated every moment, rather than numerical values performed by a computer. Fits the fitted solution to the guessed solution. Therefore, the calculated refractive index and extinction coefficient of the optical film 112 corresponding to the single wavelength can more accurately reflect the current optical properties of the optical film 112 .

在本揭露的實施例中，根據光學薄膜112當前的穿透率和/或反射率來推算出光學薄膜112於所述單一波長所對應的折射率的算式如下式(1)所示。 其中，當鍍膜機110用以製鍍多層膜堆時，n為當下膜層之折射率，α為當下膜層之前一層的導納值的實部，β為當下膜層之前一層的導納值的虛部，Y _B為當下膜層的穿透率或反射率隨厚度變化的峰值或谷值之導納值。

In the embodiment of the present disclosure, the formula for calculating the refractive index of the optical film 112 corresponding to the single wavelength according to the current transmittance and/or reflectivity of the optical film 112 is shown in the following formula (1). Wherein, when the coating machine 110 is used to coat a multilayer film stack, n is the refractive index of the current film layer, α is the real part of the admittance value of the layer before the current film layer, and β is the admittance value of the layer before the current film layer. The imaginary part of , Y _B is the admittance value of the peak or valley value of the transmittance or reflectance of the current film layer changing with thickness.

In the embodiment of the present disclosure, the single-wavelength real-time light intensity monitoring module 120 is further configured to calculate the refractive index of the optical film 112 corresponding to each wavelength according to the refractive index and extinction coefficient of the optical film 112 corresponding to a single wavelength and extinction coefficient. In the embodiment of the present disclosure, the refractive index and the extinction coefficient of the optical film 112 corresponding to each wavelength are calculated according to the refractive index and the extinction coefficient of the optical film 112 corresponding to a single wavelength by means of equal proportions or equal distances. coefficient. It is worth mentioning that the calculated refractive index and extinction coefficient of the optical film 112 corresponding to each wavelength are analytical solutions obtained through real-time calculation and updated every moment, rather than numerical fitting using a computer. The fitted solution to the guessed solution. Therefore, the calculated refractive index and extinction coefficient of the optical film 112 corresponding to each wavelength can more accurately reflect the current optical properties of the optical film 112 .

在本揭露的實施例中，透過等比例的方式以根據光學薄膜112於單一波長所對應的折射率來推算出光學薄膜112於各波長所分別對應的折射率的算式如下式(2)所示。另一方面，透過等距的方式以根據光學薄膜112於單一波長所對應的折射率來推算出光學薄膜112於各波長所分別對應的折射率的算式如下式(3)所示。 其中，λ ₀為單一波長，λ為其餘波長，n(λ ₀)為原設計之單一波長所對應的折射率，n'(λ ₀)為單一波長所對應的實際折射率，n(λ)為原設計之其餘波長所對應的折射率，n'(λ)為其餘波長所對應的實際折射率。

In the embodiment of the present disclosure, the formula for calculating the refractive index of the optical film 112 corresponding to each wavelength according to the refractive index of the optical film 112 corresponding to a single wavelength is shown in the following formula (2). . On the other hand, the formula for calculating the refractive index of the optical film 112 corresponding to each wavelength according to the refractive index of the optical film 112 corresponding to a single wavelength is as shown in the following formula (3). Among them, λ ₀ is a single wavelength, λ is the other wavelengths, n(λ ₀ ) is the refractive index corresponding to the single wavelength originally designed, n'(λ ₀ ) is the actual refractive index corresponding to the single wavelength, n(λ) is the refractive index corresponding to the remaining wavelengths of the original design, and n'(λ) is the actual refractive index corresponding to the remaining wavelengths.

The wide-wave domain real-time spectral monitoring module 130 includes a wide-wave domain (eg, 400 nm to 1500 nm) light source module 132 and a light sensor 134 , and the light sensor 134 of the wide-wave domain real-time spectral monitoring module 130 can be, for example, highly sensitive In other words, the light sensor 134 of the wide-wave domain real-time spectrum monitoring module 130 can be a camera or a CCD of the camera, but the present disclosure is not limited to this, in the present disclosure In an embodiment, the light sensor 134 of the wide-wave domain real-time spectrum monitoring module 130 may also be, for example, a real-time spectrometer.

In the embodiment of the present disclosure, the single-wavelength real-time light intensity monitoring module 120 can also be integrated into the wide-wave domain real-time spectrum monitoring module 130 .

廣波域即時光譜監控模組130用以根據光學薄膜112於各波長所分別對應的折射率與消光係數來推算出光學薄膜112的當前厚度，其算式如下式(4)所示。 其中，δ為當下膜層之當前厚度，n為各波長所分別對應的折射率，α為當下膜層之前一層的導納值的實部，β為當下膜層之前一層的導納值的虛部。值得一提的是，所推算出之光學薄膜112的當前厚度乃是經由即時計算所得出之每時每刻即時更新的解析解，而非使用電腦進行數值擬合所猜解的擬合解。因此，所推算出之光學薄膜112的當前厚度為更精確的解析解而非可能因誤差累積而有所誤差之擬合解。

The wide-wave domain real-time spectrum monitoring module 130 is used to calculate the current thickness of the optical film 112 according to the refractive index and extinction coefficient of the optical film 112 corresponding to each wavelength, and the calculation formula is shown in the following formula (4). Among them, δ is the current thickness of the current film layer, n is the refractive index corresponding to each wavelength, α is the real part of the admittance value of the layer before the current film layer, and β is the imaginary value of the admittance value of the layer before the current film layer. Department. It is worth mentioning that the estimated current thickness of the optical film 112 is an analytical solution obtained through real-time calculation and updated every moment, rather than a fitting solution guessed by numerical fitting using a computer. Therefore, the estimated current thickness of the optical film 112 is a more accurate analytical solution rather than a fitting solution that may have errors due to accumulation of errors.

In the embodiment of the present disclosure, the monitoring system 100 for coating the optical film already knows the design thickness of the optical film 112 in advance (for example, the system default value or the setting value input by the operator), so when the wide-wave domain real-time When the current thickness of the optical film 112 estimated by the spectrum monitoring module 130 is equal to the design thickness, it means that the plating stop point has been reached. In other words, the wide-wave domain real-time spectrum monitoring module 130 also determines whether the optical film 112 has reached the stopping point according to the current thickness of the optical film 112 . When the optical film 112 reaches the coating stop point, the coating machine 110 is notified to stop coating.

FIG. 2 is a flowchart of a monitoring method 1000 for forming an optical film according to an embodiment of the present disclosure. The monitoring method 1000 for forming an optical film includes steps 1100 to 1800 . The monitoring method 1000 for producing optical thin films especially refers to the application process when the coating machine 110 is used to produce a multi-layer film stack. Please refer to FIG. 1 and FIG. 2 together. In step 1100, the coating machine 110 starts to coat the lower film layer. In step 1200, the single-wavelength real-time light intensity monitoring module 120 is used to measure the transmittance and/or reflectivity of the lower layer every moment during the process of coating the lower layer by the coating machine 110. to calculate the refractive index and extinction coefficient of the current film layer corresponding to the single wavelength. In step 1300, in the process of coating the current film layer by the coating machine 110, the corresponding refractive index and extinction coefficient of the current film layer at the single wavelength are calculated at every moment according to the corresponding refractive index and extinction coefficient of the current film layer at each wavelength. refractive index and extinction coefficient. In step 1400, the wide-wave domain real-time spectrum monitoring module 130 is used to calculate the refractive index and extinction coefficient corresponding to the current film layer at each wavelength at every moment during the process of coating the current film layer by the coating machine 110. Displays the current thickness of the underlying layer.

In step 1500 , according to the refractive index and extinction coefficient of the current film layer corresponding to each wavelength and the current thickness of the current film layer, it is determined whether the design thickness needs to be corrected. If it is determined that the design thickness needs to be corrected, the process proceeds to step 1600 , the correction of the design thickness is performed, and then the process proceeds to step 1700 . It is worth mentioning that the correction of the design thickness is based on the refractive index and extinction coefficient of the current film corresponding to each wavelength and the current thickness of the current film, and the refraction of the current film corresponding to each wavelength is corrected. The ratio and extinction coefficient and the current thickness of the current film are analytical solutions obtained by real-time calculation that are updated every moment, rather than the fitting solutions guessed by numerical fitting using a computer. Therefore, the present disclosure The effect of the correction of the design thickness is better. In the embodiment of the present disclosure, the error compensation effect is achieved by modifying the design thickness. In other words, the present disclosure has the effect of compensating for the error of the front layer.

In step 1700, it is determined whether the current thickness is equal to the design thickness. If so, it means that the stop point has been reached, and the process goes to step 1800 to notify the coating machine 110 to stop the current layer coating and start the next layer coating; if not, it means that the stop point has not been reached. Plating dots, go back to step 1200.

In view of the above, the present disclosure proposes a monitoring system and method for producing optical films. By combining a single-wavelength real-time light intensity monitoring module and a wide-wave domain real-time spectrum monitoring module, the optical properties of the optical film can be monitored and controlled in real time. The change of the film thickness during film growth can be used to compensate the front layer error accordingly, so that the yield can be effectively and greatly improved.

The foregoing has outlined features of several embodiments so that those skilled in the art may better understand aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures, thereby achieving the same objectives and/or achieving the same advantages as the embodiments described herein . Those skilled in the art should also understand that these equivalent constructions do not depart from the spirit and scope of the present disclosure, and they can make various changes, substitutions and alterations without departing from the spirit and scope of the present disclosure.

100 : Monitoring system for coating optical film 110 : Coating Machine 112 : Optical Film 120 : Single-wavelength real-time light intensity monitoring module 122 : single wavelength light source module 124 : light sensor 130 : Wide-wave domain real-time spectral monitoring module 132 : Wide-wave domain light source module 134 : light sensor 1000 : Monitoring method for producing optical film 1100-1800 : Steps

A better understanding of aspects of the present disclosure can be obtained from the following detailed description taken in conjunction with the accompanying drawings. It should be noted that, according to standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased in order to clarify the discussion. 1 is a schematic diagram of a monitoring system for producing optical films according to an embodiment of the present disclosure. FIG. 2 is a flowchart of a monitoring method for forming an optical film according to an embodiment of the present disclosure.

1000 : Monitoring method for producing optical film 1100-1800 : Steps

Claims (10)

A monitoring system for producing optical films, comprising: a coating machine for coating an optical film; A single-wavelength real-time light intensity monitoring module is used to instantly calculate a refractive index and an extinction coefficient of the optical film at a wavelength during the process of coating the optical film by the coating mechanism, and then according to the optical film at the wavelength The corresponding refractive index and the extinction coefficient are calculated to calculate a refractive index and an extinction coefficient corresponding to each wavelength of the optical film; and A wide-wave domain real-time spectrum monitoring module for calculating a current thickness of the optical film according to the refractive index and the extinction coefficient corresponding to each wavelength of the optical film, and judging the optical film according to the current thickness Whether the film has reached a stop point. The monitoring system for producing optical films as claimed in claim 1, wherein the single-wavelength real-time light intensity monitoring module comprises a single-wavelength light source module with the wavelength and a light sensor, and the light sensor is used for measuring Measure a transmitted light intensity when the light beam emitted by the single-wavelength light source module passes through the optical film, and the single-wavelength real-time light intensity monitoring module is used to calculate a transmittance and a reflection according to the transmitted light intensity at least one of the ratios, so as to calculate the refractive index and the extinction coefficient of the optical film corresponding to the wavelength. The monitoring system for producing an optical film as claimed in claim 1, wherein the optical film is calculated according to the refractive index and the extinction coefficient corresponding to the wavelength of the optical film by means of equal proportions or equal distances. The refractive index and the extinction coefficient corresponding to each wavelength respectively. The monitoring system for producing optical films as claimed in claim 1, wherein when the coating machine is used to produce a multi-layer film stack, the wide-wave domain real-time spectrum monitoring module is further used to monitor a current state corresponding to the optical film. The current thickness of the film layer is used to determine whether a design thickness needs to be corrected. The monitoring system for producing an optical film as claimed in claim 4, wherein when it is determined that the design thickness needs to be corrected, the wide-wave domain real-time spectrum monitoring module is further configured to perform the monitoring of each optical film according to the lower film layer corresponding to the optical film. The design thickness is modified according to the refractive index and the extinction coefficient corresponding to the wavelength and corresponding to the current thickness of the lower layer of the optical film. A monitoring method for producing a coated optical film, comprising: A refractive index and an extinction coefficient corresponding to a wavelength of the optical film are calculated in real time during the process of coating an optical film in a coating mechanism by a single-wavelength real-time light intensity monitoring module, and then according to the wavelength of the optical film. The corresponding refractive index and the extinction coefficient are calculated to calculate a refractive index and an extinction coefficient corresponding to each wavelength of the optical film; calculating a current thickness of the optical film according to the refractive index and the extinction coefficient corresponding to each wavelength of the optical film by a wide-wave domain real-time spectrum monitoring module; and According to the current thickness of the optical film, it is judged whether the optical film has reached a stopping point. The monitoring method for producing an optical film as claimed in claim 6, wherein the single-wavelength real-time light intensity monitoring module comprises a single-wavelength light source module having the wavelength and a light sensor, wherein the single-wavelength real-time light intensity monitoring module The method for calculating the refractive index and the extinction coefficient of the optical film corresponding to the wavelength by the light intensity monitoring module includes: measuring a transmitted light intensity when the light beam emitted by the single-wavelength light source module passes through the optical film by the light sensor; calculating at least one of a transmittance and a reflectance based on the transmitted light intensity; and The refractive index and the extinction coefficient of the optical film corresponding to the wavelength are calculated according to at least one of the transmittance and the reflectance. The monitoring method for producing an optical film as claimed in claim 6, wherein the optical film is calculated according to the refractive index and the extinction coefficient of the optical film corresponding to the wavelength by means of equal proportions or equal distances. The refractive index and the extinction coefficient corresponding to each wavelength respectively. The monitoring method for producing an optical film according to claim 6, further comprising: When the coating machine is used to coat a multi-layer film stack, it is determined whether a design thickness needs to be corrected according to the current thickness of an undercoat layer corresponding to the optical film. The monitoring method for producing an optical film according to claim 9, further comprising: When it is determined that the design thickness needs to be corrected, it is performed according to the refractive index and the extinction coefficient corresponding to the lower layer of the optical film at each wavelength and the current thickness of the lower layer corresponding to the optical film Modification of the design thickness.

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