WO2015010713A1

WO2015010713A1 - Closed loop control by measuring optical properties

Info

Publication number: WO2015010713A1
Application number: PCT/EP2013/065411
Authority: WO
Inventors: Frank Schnappenberger; Anke Hellmich
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2013-07-22
Filing date: 2013-07-22
Publication date: 2015-01-29
Anticipated expiration: 2016-01-22
Also published as: TW201520538A; CN105378569A

Abstract

A method and an apparatus for processing a substrate, particularly for processing a large area substrate are described. The method for processing a large area substrate includes: transporting a large area substrate in a substantially vertically arranged state through a chamber arrangement of an apparatus for processing a large area substrate at a transportation speed; processing the large area substrate using a processing device of the apparatus for processing a large area substrate; monitoring at least one optical property of the substantially vertically arranged large area substrate using a measurement arrangement, wherein the substantially vertically arranged large area substrate is illuminated with diffuse light; and controlling at least one process parameter based on the monitored at least one optical property of the large area substrate.

Description

CLOSED LOOP CONTROL BY MEASURING OPTICAL PROPERTIES

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to processing methods and apparatuses used for operating said methods. Particularly, embodiments of the present disclosure relate to processing methods and apparatuses in which process parameters are controlled based on monitored properties of a substrate. The present disclosure particularly relates to in-line processing methods and apparatuses which are particularly adapted for processing and measuring vertically arranged large area substrates.

BACKGROUND

[0002] In a number of technical applications layers of different materials are deposited onto each other over a substrate. Typically, this is done in a sequence of coating or deposition steps, e.g., sputtering steps. For example, a multi-layer stack with a sequence of "material one"-"material two"-"material one" can be deposited. In order to deposit a multiple layer stack, an in-line arrangement of deposition modules can be used. A typical in-line system includes a number of subsequent processing modules, wherein processing steps are conducted in one chamber after the other such that a plurality of substrates can continuously or quasi-continuously be processed with the in-line system. By varying process parameters such as deposition rates, the transportation speed of the substrate through the deposition modules or other process parameters, different physical properties of the coating, e.g., different optical refraction properties, can be obtained. [0003] Processing of large area substrates requires process monitoring and quality inspection to ensure high and reproducible quality of the processed large area substrates. For example, for quality inspection of coatings on large area substrates it is required to determine optical properties of the coated substrate with low cost of ownership. Conventionally, quality inspection of processed substrates is done in a separate apparatus for quality inspection. When deviations of the properties of the processed substrate from the desired properties of the processed substrate are detected, the production process is analyzed with respect to a possible source causing the property deviation. This may lead to down times of the process decreasing the achievable output capacity.

[0004] Therefore, there remains a need for improved substrate processing systems in which improved quality of processed large area substrates can be achieved at optimized output capacity. Thus, there is also a need for improved methods for processing substrates, particularly capable of optimizing the output capacity.

SUMMARY

[0005] In view of the above, the present disclosure provides a method for processing a large area substrate that overcomes at least some of the problems in the art. This object is achieved at least to some extent by a method and an apparatus for processing a large area substrate according to the independent claims. Further aspects, advantages, and features of the present disclosure are apparent from the dependent claims, the description, and the accompanying drawings.

[0006] In view of the above, a method for processing a large area substrate is provided. The method for processing a large area substrate includes: transporting a large area substrate in a substantially vertically arranged state through a chamber arrangement of an apparatus for processing a large area substrate at a transportation speed; processing the large area substrate using a processing device of the apparatus for processing a large area substrate; monitoring at least one optical property of the substantially vertically arranged large area substrate using a measurement arrangement, wherein the substantially vertically arranged large area substrate is illuminated with diffuse light; and controlling at least one process parameter based on the monitored at least one optical property of the large area substrate.

[0007] According to one aspect of the present disclosure an apparatus for processing a large area substrate is provided, wherein the apparatus includes a chamber arrangement for transporting the large area substrate therethrough in a vertically arranged state, wherein the chamber arrangement includes at least one chamber, a processing device for processing the vertically arranged large area substrate and an exit port for the vertically arranged large area substrate. Further, the apparatus for processing a large area substrate includes a transport system for transporting the vertically arranged large area substrate through the chamber arrangement; a measuring arrangement comprising at least one optical measuring device, wherein the at least one optical measuring device includes an illuminating device for emitting diffuse light onto the vertically arranged large area substrate, and a first light detecting device for measuring at least one optical property of the vertically arranged large area substrate; and a controller for closed loop control of at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate.

[0008] According to another aspect of the present disclosure, an apparatus for processing a large area substrate may be retrofitted with the measuring arrangement and the controller for closed loop control as described herein. A method for retrofitting an apparatus for processing a large area substrate is disclosed including providing an apparatus for processing a large area substrate with the measuring arrangement and the controller for closed loop control as described herein.

[0009] The present disclosure is also directed to an apparatus for carrying out the disclosed methods and including apparatus parts for performing each described method steps. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, the disclosure is also directed to methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.

[0010] Further aspects, advantages, and features of the present disclosure are apparent from the dependent claims, the description, and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following: Typical embodiments are depicted in the drawings and are detailed in the description which follows. In the drawings:

Fig. 1 shows an illustrative embodiment of a method for processing a large area substrate according to embodiments described herein; Fig. 2 shows a schematic perspective view of an apparatus for processing a large area substrate according to embodiments described herein;

Fig. 3 shows a schematic perspective view of an apparatus for processing a large area substrate according to embodiments described herein; Fig. 4 shows a schematic cross-sectional view of an embodiment of an optical measuring device used in embodiments of an apparatus for processing a large area substrate according to embodiments described herein;

Fig. 5 shows a schematic cross-sectional view of an embodiment of an optical measuring device according to Fig. 4, wherein the relative position of the substrate is laterally shifted with respect to the optical measuring device compared to the relative position of the substrate to the optical measuring device as shown in Fig. 4;

Fig. 6 shows a schematic cross-sectional view of an embodiment of an optical measuring device according to Fig. 4, wherein the orientation of the substrate is tilted compared to the orientation of the substrate as shown in Fig. 4; Fig. 7 shows a schematic cross-sectional view of an embodiment of an optical measuring device used in embodiments of an apparatus for processing a large area substrate according to embodiments described herein;

Fig. 8 shows a schematic cross-sectional view of an embodiment of an measurement arrangement including a light trap and an optical measuring device used in embodiments of an apparatus for processing a large area substrate according to embodiments described herein;

DETAILED DESCRIPTION OF EMBODIMENTS

[0012] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

[0013] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0014] The term "substrate" as used herein shall embrace substrates which are typically used for display manufacturing, such as glass or plastic substrates. For Example, substrate as described herein shall embrace substrates which are typically used for an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), and the like. Unless explicitly specified otherwise in the description the term "substrate" is to be understood as "large area substrate" as specified herein. According to the present disclosure, large area substrates may have a size of at least 0.174 m². Typically the size can be about 1.4 m 2 to about 8 m 2 , more typically about 2 m 2 to about 9 m² or even up to 12 m². [0015] According to the present disclosure, the substrates, for which the apparatus, the chambers of the apparatus, and methods according to embodiments described herein are provided, are large area substrates or transport carriers having the dimensions of or for large area substrates as described herein. For instance, a carrier having a size corresponding to a single substrate being a large area substrate can be GEN 4.5, which corresponds to about 0.67 m substrates (730 x 920 mm), GEN 5, which corresponds to about 1.4 m substrates (1.1 m x 1.3 m), GEN 7.5, which corresponds to about 4.29 m substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7 m² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m substrates (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented. Yet, the respective carriers of such a size can also be utilized to support a plurality of substrates.

[0016] According to embodiments described herein, the substrates are essentially vertically- oriented. Thereby, it is to be understood that a vertically oriented substrate can have some deviation from a vertical, i.e. 90°, orientation in a processing system in order to allow for stable transport with an inclination of a few degrees, e.g. an inclination of 15° or less.

[0017] As schematically shown in Fig.l, a method for processing a large area substrate according to embodiments described herein includes: transporting 151 a large area substrate in a substantially vertically arranged state through a chamber arrangement of an apparatus for processing a large area substrate at a transportation speed; processing 152 the large area substrate using a processing device of the apparatus for processing a large area substrate; monitoring 153 at least one optical property of the substantially vertically arranged large area substrate using a measurement arrangement, wherein the substantially vertically arranged large area substrate is illuminated with diffuse light; and controlling 154 at least one process parameter based on the monitored at least one optical property of the large area substrate. Thereby, a method for processing a large area substrate is provided with which process parameters for processing a large area substrate can be adjusted in reaction to detected deviations from desired preselected properties which are intended to be obtained by processing the substrate. Hence, methods for processing a large area substrate according to embodiments described herein are capable of substantially eliminating or at least reducing down times of the process. Thus, by employing a method for processing a large area substrate, according to embodiments described herein, the output capacity and processing efficiency can be increased.

[0018] According to embodiments of the method, which can be combined with other embodiments of the method described herein, processing 152 the large area substrate includes at least one of depositing a coating onto the large area substrate, mechanically treating the surface of the large area substrate and chemically treating the large area substrate. According to embodiments, processing 152 the large area substrate includes using an apparatus for processing a large area substrate as described herein, in particular using a processing device as described herein.

[0019] According to embodiments of the method, which can be combined with other embodiments of the method described herein, monitoring 153 at least one optical property of the large area substrate includes at least one of measuring reflectance from the large area substrate and measuring transmission through the large area substrate. According to embodiments, monitoring 153 at least one optical property of the large area substrate includes using an apparatus for processing a large area substrate as described herein, in particular using a measuring arrangement as described herein.

[0020] According to embodiments of the method, which can be combined with other embodiments of the method described herein, monitoring 153 at least one optical property of the large area substrate includes moving at least one optical measuring device of the measuring arrangement vertical to a transport direction of the large area substrate. Thereby, multiple measurements at various positions along a moving axis of the at least one optical measuring device 210, e.g. along the line 222 as indicated in Fig. 3, may be carried out. It is to be understood, that multiple measurements by multiple optical measuring devices at various positions along various moving axes, e.g. moving axes which are parallel to the line 222 as indicated in Fig. 3, may be carried out.

[0021] According to embodiments of the method, which can be combined with other embodiments of the method described herein, monitoring 153 at least one optical property of the large area substrate is performed while the large area substrate moves relative to the measuring arrangement at the transportation speed. According to embodiments of the method, which can be combined with other embodiments of the method described herein, the transportation speed is of at least 1 m/min, particularly of at least 20 m/min, more particularly of at least 35 m/min, e.g. 50 m/min. [0022] According to embodiments of the method, which can be combined with other embodiments of the method described herein, controlling 154 at least one process parameter includes at least one of controlling a gas flow, controlling a power supply, controlling a target rotation, controlling a transportation speed of the large area substrate, controlling an orientation of the large area substrate, or other process parameters used for processing the substrate. According to embodiments, controlling 154 at least one process parameter includes using an apparatus for processing a large area substrate as described herein, in particular using a controller for closed loop control of at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate. [0023] According to embodiments of the method, which can be combined with other embodiments of the method described herein, controlling 154 at least one process parameter includes a closed loop control. Thereby, a method for processing a large area substrate is provided with which process parameters for processing a large area substrate can be adjusted in reaction to detected deviations from desired preselected properties which are intended to be obtained by processing the substrate.

[0024] According to embodiments of the method, which can be combined with other embodiments of the method described herein, controlling 154 at least one process parameter includes calculating a correction value based on the monitored at least one optical property of the large area substrate. The correction value is used to adapt the at least one process parameter in order to compensate for any detected deviations from a desired preselected property of the processed substrate.

[0025] Fig. 2 shows an apparatus 100 for processing a large area substrate 120 according to embodiments described herein. According to embodiments, the apparatus 100 includes a chamber arrangement 110 for transporting the large area substrate 120 therethrough in a vertically arranged state, wherein the chamber arrangement 110 includes at least one chamber, a processing device 230 for processing the vertically arranged large area substrate 120 and an exit port 112 for the vertically arranged large area substrate 120. Further, the apparatus 100 for processing a large area substrate 120 according to embodiments described herein includes a transport system (not shown) for transporting the vertically arranged large area substrate 120 through the chamber arrangement 110 and a measuring arrangement 200 including at least one optical measuring device 210, wherein the at least one optical measuring device 210 includes an illuminating device 211 for emitting diffuse light onto the vertically arranged large area substrate, and a first light detecting device 212 for measuring at least one optical property of the vertically arranged large area substrate. Yet further, the apparatus for processing a large area substrate includes a controller 141 for closed loop control of at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate 120.

[0026] According to embodiments of the apparatus, which can be combined with other embodiments of the apparatus described herein, the controller 141, e.g., a proportional-integral - derivative controller (PID controller), is connected with the first light detecting device 212 and with at least one processing unit of the apparatus 100. Further the controller 141 may be configured for controlling the at least one process parameter of the at least one processing unit based on the measured at least one optical property of the substantially vertically arranged large area substrate 120.

[0027] According to embodiments of the apparatus, which can be combined with other embodiments of the apparatus described herein, the at least one processing unit of the apparatus 100 is at least one of a gas flow unit 143, a power supply unit 142, a target control unit 144, and a control unit of the transport system 145.

[0028] According to embodiments, which can be combined with other embodiments described herein, the measuring arrangement 200 may be provided within the chamber arrangement 110, for example within a vacuum chamber of the chamber arrangement, as exemplarily shown in Fig. 2. Thereby, the time interval between processing the substrate and measuring the substrate can be reduced leading to a faster reaction in response to detected deviations form desired preselected properties which are intended to be obtained by processing the substrate.

[0029] According to embodiments, which can be combined with other embodiments described herein, the measuring arrangement 200 comprising at least one optical measuring device 210 for measuring at least one optical property of the vertically arranged large area substrate is provided behind the exit port 112 of the apparatus 100 for processing the large area substrate, as exemplarily shown in Fig. 3. By providing the measuring arrangement behind the exit port of the apparatus for processing the large area substrate, an apparatus for processing a large area substrate may be retrofitted with the measuring arrangement as described herein in a simple way.

[0030] According to embodiments, which can be combined with other embodiments described herein the measuring arrangement 200 may include at least three optical measurements devices 210 as exemplarily shown in Figs. 1 and 3. The at least three optical measurement devices may be arranged at different heights of a substantially vertical line, as exemplarily indicated with reference number 222 in Fig. 3. The at least three optical measurement devices can also be arranged at different heights on different substantially vertically lines, e.g. lines which are parallel to the line indicated with reference number 222 in Fig. 3. By providing at least three optical measurement devices, multiple measurements of the substrate may be carried out at the same time. Measurements from different measuring devices may be compared to obtain information about the uniformity of the substrate. Thereby, high accuracy measurements at selected positions of the substrate can be achieved. Therefore, characteristics of a processed substrate can be measured and monitored for ensuring high, reproducible quality of the processed substrate. According to embodiments, which can be combined with other embodiments described herein, the first light detecting device may include the capability to process visible radiation. According to embodiments, the first light detecting device may be adapted for processing radiation in the extra-optical range, such as infrared or ultraviolet radiation. For instance, the first light detecting device can be an optical sensor that may be adapted to process radiation in the visible radiation range of 380-780 nm and/or in the infrared radiation range of 780 nm to 3000 nm and/or in the ultraviolet radiation range of 200 nm to 380 nm. For example, the first light detecting device may be a photo sensor or a CCD-sensor (charged coupled devices). The first light detecting device can be provided for the acquisition of measurement data as well as for the acquisition of reference data. Further, the first light detecting device can include signal outlet ports which can be connected to the controller 141 for closed loop control.

[0031] According to embodiments, which can be combined with other embodiments described herein, the first light detecting device may be connected to the controller 141 for closed loop control via a cable or wireless connection. The controller 141 for closed loop control can be adapted to inspect and analyze the signals of the first light detecting device. If any characteristic of the substrate is measured which is defined as non-normal, the controller 141 for closed loop control may detect the change and trigger a reaction, such as a control, in particular an adaptation, of the at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate.

[0032] According to embodiments, which can be combined with other embodiments described herein, the controller 141 for closed loop controls may control or adapt at least one process parameter selected from a gas flow, controlling a power supply, a target rotation, transportation speed of the large area substrate, an orientation of the large area substrate, or any other process parameters used for processing the substrate.

[0033] According to embodiments, which can be combined with other embodiments described herein, the at least one optical property of the substrate measured by the first light detecting device of the at least one optical measuring device includes a reflectance from the substrate. [0034] As exemplarily shown in Fig. 4 illustrating a schematic cross-sectional view of an embodiment of an optical measuring device 210 used in embodiments of the apparatus and methods as described herein, the illuminating device 211 of the at least one optical measuring device 210 includes an integrating sphere 213 and a light source 214 emitting light into the integrating sphere 213. According to embodiments, which can be combined with other embodiments described herein, the light source is configured for emitting light in the visible radiation range of 380-780 nm and/or in the infrared radiation range of 780 nm to 3000 nm and/or in the ultraviolet radiation range of 200 nm to 380 nm.

[0035] According to embodiments, which can be combined with other embodiments described herein, the light source 214 of the illuminating device 211 is arranged such that light can be emitted into the integrating sphere 213. The light source may be arranged within the integrating sphere 213, or attached to an inner wall of the integrating sphere 213. According to embodiments, the light source 214 can be arranged outside the integrating sphere, wherein the wall of the integrating sphere includes an opening which is configured such that light emitted from the light source can shine into the interior of the integrating sphere. [0036] According to embodiments, which can be combined with other embodiments described herein, the light source 214 may be configured, e.g., as filament bulb, as tungsten halogen bulb, as LEDs, high-power LEDs or Xe- Arc-Lamps. The light source 214 may be configured switchable such that the light source can be switched on and off for short times. For the purpose of switching, the light source can be connected to the controller 141.

[0037] According to embodiments, which can be combined with other embodiments described herein, the at least one optical measuring device is positioned on one side of the substrate 120 to be measured, as exemplarily shown in Fig 4. According to embodiments, the integrating sphere 213 is arranged relative to the substantially vertically arranged substrate 120 at a distance Dl with respect to a first surface 121 of the substrate of Dl= 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm.. As exemplarily shown in Fig 4, the integrating sphere 213 can be provided with a light exit port 216 arranged at a distance Dl with respect to a first surface 121 of the substrate of Dl= 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm. Thereby, diffuse light emitted from the integrating sphere through the light exit port 216 can be shone onto the substrate for measurement of at least one optical property of the substrate. By illuminating the substrate with diffuse light, the light shone onto the substrate is of the same intensity throughout an illuminated portion of the substrate. According to some embodiments, which can be combined with other embodiments described herein, the emitted diffuse light can be characterized by emitting the light at a plurality of angles, particularly with a uniform angular distribution of the intensity of the light. For example, this can be generated by diffuse reflection in the integrating sphere, e.g. an Ulbricht sphere, where the material in the sphere is selected for providing diffuse reflection. [0038] Due to the measurement arrangement according to embodiments described herein, the tolerance of the measurement system with respect to substrate position and substrate warping can be increased. For example, a substrate warping resulting in an angle deviation of +-2°, e.g. +- 1° can be within the tolerances for measurements described herein.

[0039] As exemplarily illustrated in Fig. 4, a beam of light, which is illustrated as a solid line with arrows indicating the direction of the light, may have a position of origin P on the interior surface of the integrating sphere before the beam exits the exit port 216. The beam may be transmitted through the substrate or reflected from the substrate, as exemplarily shown in Fig. 4, and in case of reflectance, enter the light exit port 216 with an angle of reflectance. According to embodiments, which can be combined with other embodiments described herein, the first light detecting device 212 is configured and arranged such that light reflected from the substrate 120, e.g. from the first surface of the substrate 121, can be detected by the first light detecting device 212. An angle between a light beam exiting the integrating sphere 213 through the exit port 216 and the reflected beam entering the exit port 216 may be referred to as angle of beam β in the present disclosure. [0040] According to embodiments, as exemplarily shown in Fig. 4, the optical measuring device 210 includes a measuring axis 217. According to embodiments, the measuring axis 217 is substantially normal to a first surface 121 of the substrate 120. In the present disclosure, a direction under which a light beam reflected from the substrate is detected by the first light detecting device is referred to as the detection direction of the first light detecting device, as exemplarily indicated in Fig. 4 by reference number 218. According to embodiments, the angle a between the detection direction 218 and the measuring axis 217 is within a range of 2° to 10°, particularly within a range of 2° to 8°, more particularly within a range of 2° to 4°, preferably below 4°. [0041] According to embodiments, which can be combined with other embodiments described herein, the integrating sphere 213 has an inner diameter of 150 mm or less, particularly of 100 mm or less, more particularly of 75 mm or less. According to embodiments, by providing an illuminating device with a larger integrating sphere, the influence of the size of the light exit port 216 on the illumination quality of the substrate can be compensated, in particular minimized. [0042] According to embodiments, which can be combined with other embodiments described herein, the light exit port 216 of the integrating sphere 213 may have a diameter of 25 mm or less, particularly of 15 mm or less, more particularly of 10 mm or less. By increasing the diameter of the exit port, a larger portion of the substrate may be illuminated for conducting a measurement of the at least one optical property of the substrate. [0043] According to embodiments, which can be combined with other embodiments described herein, the first light detecting device 212 is configured and arranged such that no direct light from the light source 214 is detected by the first light detecting device 212. For example, screening means (not shown) may be provided within the integrating sphere 213, which prevent light emitted by the light source from directly hitting the first light detecting device 212. Such screening means may, for example, be realized by shields, apertures or lenses, which are configured and arranged such that no direct light emitted by the light source can hit the first light detecting device 212.

[0044] According to embodiments, which can be combined with other embodiments described herein, the first light detecting device 212 is configured and arranged such that no light reflected from the inside of the integrating sphere is detected by the first light detecting device 212. For example, the first light detecting device 212 can be arranged such that only light entering through the light exit port 216 of the integrating sphere 213, e.g. due to reflection on the substrate 120, may be detected by the first light detecting device 212.

[0045] One problem associated with measuring properties of a vertically arranged large area substrate is that the large area substrate tends to warp due to gravitational forces acting on the substrate. Such a warping of the substrate may cause inaccuracies of optical measurements since the relative position of the substrate to the measurement device may vary depending on the position and degree of warping. As outlined in the following with reference to Figs. 5 and 6, influence of substrate warping, e.g. due to gravitational forces acting on a vertically arranged substrate, on the measurement accuracy of the measuring arrangement as described herein can substantially be eliminated.

[0046] With reference to Figs. 5 and 6, the influence of warping of the substrate, e.g. due to gravitational forces acting on a vertically arranged substrate, is analyzed. As warping may be considered as an overlap of tilting and shifting the substrate relative to the original orientation of the substrate, the influence of tilting and shifting the substrate are analyzed separately. Accordingly, with reference to Fig. 5 the influence of shifting the substrate compared to a reference orientation of the substrate as shown in Fig. 4 is analyzed. Further, with reference to Fig. 6, the influence of tilting the substrate compared to the reference orientation of the substrate as shown in Fig. 4 is evaluated.

[0047] Fig. 5 shows a schematic cross-sectional view of an embodiment of an optical measuring device according to Fig. 4, wherein the relative position of the substrate is laterally shifted with respect to the optical measuring device compared to the relative position of the substrate to the optical measuring device as shown in Fig. 4. In Fig. 5 a lateral shift of the substrate 120 is indicated by AD. As illustrated in Fig. 5, when the substrate is shifted by a distance of AD the position of origin P of a light beam which is detected by the first light detecting device after reflection from the substrate 120 appears to have been travelled away from the first light detecting device 212 compared to the position of origin P of the light beam as shown in Fig. 4. As illustrated in Fig. 5, the angle of beam (β+Δβ) increases with increasing distance (D1+ AD) between the light exit port 216 of the integrating sphere 213 and the substrate 120. Accordingly, the size of the light exit port 216 as well as the position and size of the first light detecting device 212 determines the maximum distance between the substrate and the light exit port 216, at which light reflected from the substrate may be detected by the first light detecting device 212. Since for measuring at least one optical property of the substrate, the substrate is illuminated with diffuse light, the light shone onto the substrate is of the same intensity throughout the illuminated portion of the substrate. Accordingly, the accuracy of the measured at least one optical property of the substrate is independent of a distance between the substrate and the measurement arrangement as described herein, in particular at the distance of 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm.

[0048] Fig. 6 shows a schematic cross-sectional view of an embodiment of an optical measuring device according to Fig. 4, wherein the relative position of the substrate is tilted compared to the position of the substrate as shown in Fig. 4. In Fig. 6 a tilt of the substrate 120 is indicated by δ. As illustrated in Fig. 6, when the substrate is tilted by an angle of δ, the position of origin P of a light beam which is detected by the first light detecting device 212 after reflection from the substrate 120 appears to have been travelled away from the first light detecting device 212 compared to the position of origin P of the light beam as shown in Fig.4. Further, as illustrated in Fig. 6 the angle of beam (β+δ) may vary depending on the angle of tilt δ of the substrate. Accordingly, the size of the light exit port 216 as well as the position and size of the first light detecting device 212 determines the maximum tilt of the substrate at which light reflected from the substrate may be detected by the first light detecting device 212. Since for measuring at least one optical property of the substrate, the substrate is illuminated with diffuse light, the light shone onto the substrate is of the same intensity throughout the illuminated portion of the substrate. Accordingly, the accuracy of the measured at least one optical property of the substrate is independent of a tilt δ of the substrate, e.g. due to warping of the vertically arranged substrate caused by gravitational forces.

[0049] As outlined above with reference to Figs. 5 and 6, influence of substrate warping, e.g. due to gravitational forces acting on a vertically arranged substrate, on the measurement accuracy of the measuring arrangement as described herein can substantially be eliminated. Therefore, apparatuses for processing a large area substrate as described herein are capable of measuring at least one optical property of the substantially vertically arranged large area substrate. Particularly, apparatuses for processing a large area substrate according to embodiments described herein are suitable for measuring at least one optical property of the substantially vertically arranged large area moving substrate, in particular of substrates moving at a transportation speed of at least 1 m/min, particularly of at least 20 m/min, more particularly of at least 35 m/min, e.g. 50 m/min. Further, by providing an apparatus for processing a large area substrate according to embodiments described herein, high accuracy measurements of at least one optical property of the substrate can be measured in a distance up to 100 mm from between the substrate and the measuring arrangement and a substrate tilt up to + 2°, e.g. by warping of the large area substrate.

[0050] According to embodiments, which can be combined with other embodiments described herein, the at least one optical measuring device 210 further comprises a second light detecting device 215 for measuring the at least one optical property of the substantially vertically arranged large area substrate. As exemplarily shown in Fig. 7, according to embodiments described herein, the second light detecting device 215 may be arranged opposite to the illuminating device 211, particularly opposite to the light exit port 216 of the integrating sphere, on another side of the substrate 120 than the illuminating device 211, particularly on the side of the second surface 122 of the substrate 120. According to embodiments, the second light detecting device 215 is arranged relative to the substantially vertically arranged substrate 120 at a distance D2 with respect to a second surface 122 of the substrate 120 of D2 = 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm.

[0051] According to embodiments, which can be combined with other embodiments described herein, the second light detecting device may include the capability to process visible radiation. The second light detecting device may be adapted for processing radiation in the extra-optical range, such as infrared or ultraviolet radiation. For instance, the second light detecting device can be an optical sensor that may be adapted to process radiation in the visible radiation range of 380- 780 nm and/or in the infrared radiation range of 780 nm to 3000 nm and/or in the ultraviolet radiation range of 200 nm to 380 nm. The second light detecting device may be a photo sensor or a CCD-sensor (charged coupled devices). The second light detecting device can be provided for the acquisition of measurement data as well as for the acquisition of reference data. The second light detecting device can include signal outlet ports which may be connected to the controller 141 for closed loop control. [0052] According to embodiments, which can be combined with other embodiments described herein, the at least one optical property of the substrate measured by the second light detecting device of the at least one optical measuring device includes a transmission through the substrate. By providing a measurement arrangement with a first light detecting device and a second light detecting device it is possible to measure both the transmission and the reflectance of the substrate. Thereby, more information with respect to the properties of the substrate can be obtained. Thus, at least one process parameter can be controlled or adjusted more accurately based on the measured at least one optical property of the substrate.

[0053] According to embodiments, which can be combined with other embodiments described herein, the second light detecting device may be connected to the controller 141 for closed loop control via a cable or wireless connection. The controller 141 for closed loop control can be adapted to inspect and analyze the signals of the second light detecting device. If any characteristic of the substrate is measured which is defined as non-normal, the controller 141 for closed loop control may detect the change and trigger a reaction, such as a control, in particular an adaptation, of the at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate.

[0054] According to embodiments, which can be combined with other embodiments described herein, a distance Dl between the integrating sphere 213 of the illuminating device 21 and the first surface 121 of the substrate 120 and/or a distance D2 between the second light detecting device 215 and the second surface 122 of the substrate 120, which is on an opposite side of the first surface of the substrate, may be kept as small as possible. According to embodiments, the distance Dl and the distance D2 are selected such that unobstructed movement of the substrate relative to the illuminating device 211 and/or relative to the at least one optical measuring device 210 in the transport direction is possible. [0055] According to embodiments, which can be combined with other embodiments described herein, the measuring arrangement 200 further includes at least one light trap 220 which is configured and arranged for capturing light transmitted through a substrate. As exemplarily shown in Fig. 8, the at least one light trap 220 is geometrical configured such that that all incident light hits an absorber area 221. For example the light trap may be configured such that an incident light beam having an intensity Io reflects on at least 5 surfaces, before the light is reflected out of the light trap. For instance, the absorber area 221 on which light may reflect within the light trap may include black glass which reflects 5% of the incident light. Accordingly, after five reflections the light intensity I_out of the light which may be reflected out of the light trap can be calculated as 0.05 5 -Io = 3.125 10 -^"7 -Io, which is effectively zero.

[0056] According to embodiments, which can be combined with other embodiments described herein, the at least one light trap 220, in particular the arrangement of the absorber area 221, is configured for absorbing all incident light over all measured wavelengths, such as the wavelength within the visible radiation range of 380-780 nm and/or in the infrared radiation range of 780 nm to 3000 nm and/or in the ultraviolet radiation range of 200 nm to 380 nm. According to embodiments, the at least one light trap 220 is arranged relative to the substantially vertically arranged substrate 120, in particular relative to the second surface 122 of the substrate, at a distance D3 with respect to a second surface 122 of the substrate 120 of D3 = 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm.

[0057] Although not explicitly shown, in the Figures according to embodiments described herein the second light detecting device 215 may be arranged within the at least one light trap 220. According to embodiments, a height of the at least one light trap 220 is at least 50 , particularly at least 70 , more particularly at least 85 % of the height of the substantially vertically arranged large area substrate, e.g. the height of the at least one light trap may be of the substantially same height as the vertically arranged large area substrate or the height of the at least one light trap may be of the same height as a transport carrier having dimensions of a large area substrate as described herein. Thereby, the light trap can be configured static with respect to a moving illuminating device, which may be part of the measuring device as described herein. Hence, the light trap is configured and arranged such that light emitted from a moving illuminating device, e.g. an illuminating device moving along a substantially vertical trajectory, can be captured by the light trap over the complete moving trajectory of the illuminating device. Thereby, any reflection from behind the first surface from which reflectance is measured can substantially be eliminated.

[0058] By providing at least one light trap according to embodiments as described herein reflectance from the substrate can be measured without distortions resulting from parasitic reflections not coming from the surface to be measured. Further, according to embodiments the size of the at least one light trap is adjusted such that providing a single light trap may be sufficient to essentially eliminate parasitic reflection over the height of the substrate at which measurements are carried out.

[0059] According to embodiments, which can be combined with other embodiments described herein, the at least one optical measuring device 210 can be configured movable along a substantially vertical direction with respect to a transport direction of the substantially vertically arranged large area substrate. Thereby, multiple measurements at various positions along a moving axis of the at least one optical measuring device 210, e.g. along the line 222 as indicated in Fig. 3, may be carried out. The at least one first movable measuring device can be coupled to a rail for supporting a manually operated movement of the at least one optical measuring device may be provided. [0060] According to embodiments, which can be combined with other embodiments described herein, an actuator for performing a movement of the at least one first movable measuring device along a trajectory, e.g., a linear trajectory, may be provided. The actuator may be operated by a source of energy in the form of an electric current, hydraulic fluid pressure or pneumatic pressure converting the energy into motion. According to some embodiments, the actuator for moving the at least one first movable positioning pulley can be an electrical motor, a linear motor, a pneumatic actuator, a hydraulic actuator or a piezoelectric actuator.

[0061] According to embodiments, which can be combined with other embodiments described herein, the apparatus for processing a large area substrate is an in-line processing apparatus. An in-line processing apparatus for processing a large area substrate according to embodiments described herein may include a sequence of chambers, i.e. a chamber arrangement 110 including at least one chamber. According to embodiments, the at least one chamber of the chamber arrangement 110 includes chamber walls with openings, wherein the openings are configured for transferring essentially vertically- oriented substrates therethrough. Accordingly, the openings can have the shape of a slit, particularly a vertical slit. According to embodiments, which can be combined with other embodiments described herein, the openings of the at least one chamber may include locks which can be opened or closed.

[0062] According to embodiments, which can be combined with other embodiments described herein, the at least one chamber of the chamber arrangement 110 can have a flange for connecting a vacuum system, such as a vacuum pump or the like. Thereby, the at least one chamber can be evacuated.

[0063] According to embodiments, which can be combined with other embodiments described herein, the at least one chamber of the chamber arrangement may be a chamber selected from the group consisting of: a buffer chamber, a heating chamber, a transfer chamber, a cycle-time- adjusting chamber, a deposition chamber, a processing chamber or the like.

[0064] According to embodiments, which can be combined with other embodiments described herein, at least one chamber of the chamber arrangement may be a processing chamber. According to the present disclosure, a "processing chamber" may be understood as a chamber in which a processing device for processing a substrate is arranged. Accordingly, a processing device according to embodiments described herein may be understood as any device used for processing a substrate. For example, the processing device may be a deposition source for depositing a layer onto the substrate. Accordingly, a processing chamber including a deposition source may be referred to a deposition chamber in the present disclosure. The deposition chamber may be a chemical vapor deposition (CVD) chamber or a physical vapor deposition (PVD) chamber.

[0065] According to embodiments, which can be combined with other embodiments described herein, the processing device being a deposition source is provided as a sputtering target, such as a rotatable sputtering target which may be used in a PVD chamber, such as a PVD chamber available from AKT®, a subsidiary of Applied Materials, Inc., Santa Clara, California or a PVD chamber available from Applied Materials Gmbh & Co. KG, located at Alzenau, Germany. According to embodiments, the deposition source and/or the processing chamber employed in embodiments of the apparatus as described herein may be a deposition source and/or a processing chamber used in the AKT Aristo PVD System available from AKT®. However, it should be understood that the sputtering target may have utility in other PVD chambers, including those chambers configured to process large area substrates produced by other manufacturers.

[0066] According to embodiments, which can be combined with other embodiments described herein, the processing device can be configured to provide a DC (direct current) sputtering, a pulse sputtering, or an MF (middle frequency) sputtering. According to embodiments, which can be combined with other embodiments described herein, the middle frequency sputtering includes frequencies in the range of 5 kHz to 100 kHz, particularly in the range of 25 kHz to 50 kHz.

[0067] According to embodiments, which can be combined with other embodiments described herein, the apparatus for processing a large area substrate may be adapted for employing sputtering techniques which are typically applied to a thin film deposition process in the course of fabricating a semiconductor, an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), and the like.

[0068] According to embodiments, which can be combined with other embodiments described herein, the at least one chamber of the chamber arrangement, which is configured as a deposition chamber, may be configured for deposition of material selected from the group consisting of: low index materials, such as Si02, MgF, mid index material, such as SiN , A1203, A1N, ITO, IZO, SiOxNy, AlOxNy and high index materials, such as Nb205, Ti02, Ta02, or other high index materials. [0069] Accordingly, according to embodiments, which can be combined with other embodiments described herein, the target material can be selected from the group consisting of: low index materials, such as Si02, MgF, mid index material, such as SiN , A1203, A1N, ITO, IZO, SiOxNy, AlOxNy and high index materials, such as Nb205, Ti02, Ta02, or other high index materials. [0070] According to embodiments, which can be combined with other embodiments described herein, the target material is typically provided either by the material to be deposited on a substrate or by the material which is supposed to react with a reactive gas in a processing area to then be deposited on the substrate after reacting with a reactive gas. [0071] According to embodiments, which can be combined with other embodiments described herein, two transport paths may be provided so that a first substrate may overtake a second substrate that is being processed. Thereby, an apparatus for processing large area substrates can be provided with which multiple substrates can be processed differently, subsequently or concurrently. [0072] According to embodiments, which can be combined with other embodiments described herein, a transportation system for moving along the transportation tracks can be provided at the bottom of the essentially vertically arranged substrate. The transportation system may include a transportation carrier for the substrate. The transportation carrier 131 can be configured as a frame structure for supporting the substrate 120, in particular for supporting the substrate in a vertically arranged state. Further, the transportation carrier may be configured having multiple sub-frames for supporting substrates, wherein the sub-frames are encompassed within a base frame. The subframes may differ in size and aspect ratio, wherein the size of the base frames of different transportation carriers essentially depends on the size of the smallest at least one chamber of the chamber arrangement. [0073] According to embodiments, which can be combined with other embodiments described herein, the sub-frames may be configured for supporting GEN 4.5, GEN 5, GEN 7.5, GEN 8.5, GEN 10, GEN 11, or GEN 12 substrates as specified herein. Further, the sub-frames can also be configured having a smaller size than the sizes of the large area substrate specified herein. According to embodiments, which can be combined with other embodiments described herein, multiple sub frames having different sizes may be arranged within the base frame of the transportation carrier. Thereby, processing of substrates having different sizes at the same time can be achieved.

[0074] According to embodiments, which can be combined with other embodiments described herein, the transport system for vertically arranged substrates may include transportation elements, e.g. rollers, and/or guiding elements for guiding the substrate or the transportation carrier along the transportation path. For example, the guiding elements can be magnetic guiding elements having a recess, e.g., two slits, through which the substrate can be transferred. The guiding elements can also include a bearing for linear movement such that a shift from a first transportation track to a second transportation track can be conducted.

[0075] According to embodiments, which can be combined with other embodiments described herein, the magnetic guiding elements are configured for contactless guiding of the substrate or the transportation carrier along the transportation path. Contactless guiding may involve a lateral tolerance between the guiding element and the substrate or the transportation carrier such that the lateral position of the substrate or the transportation carrier may vary during the transportation within the tolerance provided. Thereby, also warping effects of the substrate may occur. By using a measuring arrangement as described herein in an apparatus for processing a large area substrate according to the embodiments, a variation of the lateral position or of the substrate with respect to the measuring arrangement does not influence the accuracy of the measurement of the substrate. In other words, the measuring arrangement as described herein is capable of compensating warping effects and/or variations of the lateral position or of the substrate with respect to the measuring arrangement.

[0076] According to embodiments, which can be combined with other embodiments described herein, the transportation elements and/or the guiding elements of the transportation system can be arranged on an upper and/or a lower end of the substrate, particularly on an upper and/or a lower end of the transportation carrier for the substrate. The transportation elements can be moved synchronously for lateral transfer of the substrate within or through the chamber arrangement. The guiding elements may also be moved at the same time as the transportation elements.

[0077] According to embodiments, which can be combined with other embodiments described herein, the transportation elements may include drives for driving the transportation elements.

For example, the transportation elements may include belt drives for driving the rotation of the transportation elements in order to transport the substrates or carriers provided on the transportation rollers along the transportation paths. According to embodiments, one or more of the drives, e.g. the belt drives, can be driven by a motor.

[0078] According to embodiments described herein, the apparatus for processing a large area substrate includes an improved utilization of the processing chambers and allows for feeding of the substrates into the processing system in a continuous or quasi-continuous manner. According to typical embodiments, which can be combined with other embodiments described herein, the apparatus for processing a large area substrate includes an entry load-lock chamber for inserting a substrate into the apparatus. The entry load-lock chamber can be configured for changing the interior pressure from atmospheric pressure to vacuum, e.g. to a pressure of 10 mbar or below, or vice versa.

[0079] According to typical embodiments, which can be combined with other embodiments described herein, the apparatus for processing a large area substrate includes an exit load-lock chamber for discharging a substrate out of the apparatus. The exit load-lock chamber can be configured for changing the interior pressure from atmospheric pressure to vacuum, e.g. to a pressure of 10 mbar or below, or vice versa. According to embodiments, the exit load-lock chamber includes the exit port 112. Hence, after traveling through the chamber arrangement of the apparatus, the substrate may exit the apparatus at the exit port 112, as exemplarily shown in Fig l.

[0080] According to embodiments described herein, the chamber arrangement may include at least one vacuum chamber. The at least one vacuum chamber can be configured for transferring or processing the substrates at a pressure of 10 mbar or below. Accordingly, the entry load-lock chamber can be configured for being evacuated before a vacuum valve between the entry load- lock chamber and an adjacent downstream chamber is opened for further transport of the substrate into the adjacent chamber. Accordingly, the exit load-lock chamber can be configured for being evacuated before a vacuum valve between the exit load-lock chamber, and an adjacent upstream chamber is opened for further transport of the substrate into the exit load-lock chamber.

[0081] By providing an apparatus for processing a large area substrate according to embodiments described herein, characteristics of a processed substrate can be measured and monitored. Further, by providing a controller for closed loop control of at least one process parameter based on the measured at least one optical property of the substrate process, parameters can be adjusted in reaction to detected deviations from desired preselected properties which are intended to be obtained by processing the substrate. Hence, with the apparatus as described herein, an apparatus for processing large area substrates is provided with which non-uniformities in the structure or composition of the substrate or coatings on the substrate, for example due processing errors, can be detected and substantially be eliminated. Thereby, down times of the process can be reduced such that the output capacity and cost efficiency of the process can be increased.

[0082] According to embodiments described herein, the method for processing a large area substrate can be conducted by means of computer programs, software, computer software products and the interrelated controllers, which can have a CPU, a memory, a user interface, and input and output means being in communication with the corresponding components apparatus for processing a large area substrate

[0083] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

A method for processing a large area substrate, comprising:

transporting (151) a large area substrate in a substantially vertically arranged state through a chamber arrangement of an apparatus for processing a large area substrate at a transportation speed;

processing (152) the large area substrate using a processing device of the apparatus for processing a large area substrate;

monitoring (153) at least one optical property of the substantially vertically arranged large area substrate using a measurement arrangement, wherein the substantially vertically arranged large area substrate is illuminated with diffuse light; and controlling (154) at least one process parameter based on the monitored at least one optical property of the large area substrate.

The method according to claim 1, wherein processing (152) the large area substrate includes at least one of depositing a coating onto the large area substrate, mechanically treating the surface of the large area substrate and chemically treating the large area substrate.

The method according to claim 1 or 2, wherein monitoring (153) at least one optical property of the large area substrate includes at least one of measuring reflectance from the large area substrate and measuring transmission through the large area substrate.

The method according to any of claims 1 to 3, wherein monitoring (153) at least one optical property of the large area substrate includes moving at least one optical measuring device of the measuring arrangement vertical to a transport direction of the large area substrate.

The method according to any of claims 1 to 4, wherein monitoring (153) at least one optical property of the large area substrate is performed while the large area substrate moves relative to the measuring arrangement at the transportation speed.

The method according to any of claims 1 to 5, wherein the transportation speed is of at least

1 m/min, particularly of at least 20 m/min, more particularly of at least 35 m/min, e.g. 50 m/min.

The method according to any of claims 1 to 6, wherein controlling (154) at least one process parameter includes at least one of controlling a gas flow, controlling a power supply, controlling a target rotation, controlling a transportation speed, controlling an orientation of the large area substrate.

The method according to any of claims 1 to 7, wherein controlling (154) at least one process parameter includes a closed loop control.

The method according to any of claims 1 to 8, wherein controlling (154) at least one process parameter includes calculating a correction value based on the monitored at least one optical property of the large area substrate.

An apparatus (100) for processing a large area substrate (120), comprising:

- a chamber arrangement (110) for transporting the large area substrate (120) therethrough in a vertically arranged state, wherein the chamber arrangement (110) includes at least one chamber, a processing device for processing the vertically arranged large area substrate (120) and an exit port (112) for the vertically arranged large area substrate (120);

- a transport system (130) for transporting the vertically arranged large area substrate (120) through the chamber arrangement (110);

- a measuring arrangement (200) comprising at least one optical measuring device (210), wherein the at least one optical measuring device (210) includes an illuminating device (211) for emitting diffuse light onto the vertically arranged large area substrate, and a first light detecting device (212) for measuring at least one optical property of the vertically arranged large area substrate; and

- a controller (141) for closed loop control of at least one process parameter based on the measured at least one optical property of the substantially vertically arranged large area substrate (120).

11. The apparatus (100) according to claim 10, wherein the controller (141) is connected with the first light detecting device (212) and with at least one processing unit of the apparatus (100), and wherein the controller (141) is configured for controlling the at least one process parameter of the at least one processing unit based on the measured at least one optical property of the substantially vertically arranged large area substrate (120).

12. The apparatus (100) according to claim 11, wherein the controller (141) is connected with a second light detecting device (215) of the at least one optical measuring device (210) and with the at least one processing unit of the apparatus (100), wherein the second light detecting device (215) is configured for measuring the at least one optical property of the vertically arranged large area substrate; and wherein the controller (141) is configured for controlling the at least one process parameter of the at least one processing unit based on the measured at least one optical property of the substantially vertically arranged large area substrate (120).

13. The apparatus (100) according to claim 12, wherein the first light detecting device (212) and/or the second light detecting device (215) are arranged relative to the substantially vertically arranged large area substrate at distance of 30 mm within a tolerance of + 25 mm, particularly within a tolerance of + 20 mm, more particularly within a tolerance of + 15 mm.

14. The apparatus (100) according to any of claims 10 to 13, wherein the at least one optical property of the substantially vertically arranged large area substrate includes at least one of a reflectance from the substantially vertically arranged large area substrate, and a transmission through the substantially vertically arranged large area substrate.

15. The apparatus (100) according to claim 11 or 14, wherein the at least one processing unit of the apparatus (100) is at least one of a gas flow unit (143), a power supply unit (142), a target control unit (144), and a control unit of the transport system (145).

16. The apparatus (100) according to any of claims 10 to 15, wherein the measuring arrangement (200) allows for a substrate warping resulting in an angle deviation of +2°.