Coater conditioning mode

Abstract

A method for conditioning a coating machine to remove water and / or moisture from a processing area of ​​the coating machine is provided, wherein the processing area comprises at least one pump compartment (10) and at least one sputtering compartment (11). The method comprises the steps of loading a conditioning substrate (5) into a processing area so that the processing area is substantially filled with a conditioning substrate (5), and conditioning the coating machine by initiating a sputtering process in the processing area and / or heating of at least one pump compartment (10). During conditioning, the conditioning substrate (5) performs vibratory movement in the processing area.

Description

Technology Field

[0001] The present invention relates to a coating apparatus for coating a glass substrate by a sputtering process, in particular to a large-area coating machine. The present invention relates particularly to conditioning the coating machine after a holding process.

[0002] Generally, after the maintenance process for a large-area coating machine, the machine is closed and pumped. After pumping, the coating machine needs to be "conditioned." "Conditioning" is generally a synonym for pumping water out of the coating machine. Water needs to be adsorbed from the entire surface inside the coating machine and efficiently pumped out to be separated from the surface—a process that requires heat. Two different modern conditioning processes are known:

[0003] As soon as the pressure is reached that enables the cathode to start, the sputtering process is initiated throughout the coating machine. The provided process power of 10 kW to 120 kW per cathode is converted mainly into thermal energy and thus heats the coating machine mainly in the process compartment area, where the sputtering process is active, whereas the pump compartment is not actively heated. Although heating has the desired effect of separating water from the surface for pumping, there are two disadvantages: (1) the sputtering target is consumed without producing coated glass, and (2) the sputtered material is deposited in the empty compartment, which increases the thick layer of coating material with dense stress, which later increases the risk of crumbling (product failure) when the coating machine is in manufacturing mode.

[0004] To minimize the mentioned risk of debris, the conditioning procedure can be modified: while sputtering is performed, for example, while glass out of specification is continuously passed through the coating machine. In this way, the sputtered material is not deposited in the empty compartments on the low-quality glass that transports the sputtered material out of the coating machine. By returning it to the atmosphere, the coated glass can be reused in this process. To do so, it needs to be transported from the coating machine outlet back to the coating machine inlet. At the end of the conditioning process, the coated glass is scraped off. In this way, the risk of debris during manufacturing can be reduced. However, this risk mitigation again presents several disadvantages: (1) Glass that passes through the coating machine where all sputtering processes are active is significantly heated, and the heating process also helps to condition the pumping compartments where they are not available. When leaving the coating machine, the glass has reached a temperature of about 60 to 70°C, and thus extracts a significant amount of energy from the vacuum, which is actually required for conditioning. Returned to the atmosphere, the glass is cooled while being transported back to the coating machine inlet, where it is run through a washing machine and re-entered the coating machine to be reheated and protected from sputtering the compartment surface. (2) Running the glass in a circle through the coating machine and driving it back from the outlet to the inlet several times builds up a significant layer stack on the glass, which results in a significant loss of intrinsic stress and adhesion. Consequently, some of this coated material is removed during a harsh washing process before the coating machine inlet, which is adjusted to wash the glass that is not actually coated. These coating particles mechanically removed by the brush contaminate the washing machine and therefore need to be cleaned before manufacturing begins.

[0005] As described in US2007 / 254096A1, the chamber of the coating machine is purged with a conditioned purge gas before the coating operation, wherein the moisture content of the purge gas is set to a predetermined moisture level, in particular to a relative moisture content of up to 30%. The chamber may be at least partially heated to a temperature between 20°C and 60°C before and / or during the cleaning operation.

[0006] According to WO2006 / 127472A1, in order to dry the (deposition) chamber of a coating machine quickly and inexpensively, the chamber is flushed with dry air to remove contaminated moisture inside the chamber before use.

[0007] Accordingly, the object of the present invention is to provide an improved conditioning method and a coating device that particularly overcome the above problem.

[0008] The present invention is defined by independent claims 1 and 14. Dependent claims define embodiments of the present invention.

[0009] The present invention provides a method for conditioning a coating machine to remove water and / or moisture from the processing area of ​​the coating machine. The processing area comprises at least one pump compartment and at least one sputtering compartment. According to the method of the present invention, a conditioning substrate is loaded into the processing area of ​​the coating machine so that the entire processing area, preferably the transfer chamber, is substantially filled with the conditioning substrate. Subsequently, the conditioning process of the coating machine is performed by initiating a sputtering process in the processing area and / or by heating at least one pump compartment. During conditioning, the conditioning substrate undergoes vibratory movement (forward and backward) in the processing area.

[0010] The conditioning substrate may be a metal substrate, in particular a substrate having a specific heat capacity of at least 350 J / (kg*K), for example, an aluminum substrate. The conditioning substrate is preferably cleaned and reused after conditioning the coating machine.

[0011] Alternatively, the conditioning substrate is a low-quality glass substrate. The glass conditioning substrate can be scraped after conditioning the coating machine.

[0012] The length of the conditioning substrate preferably corresponds substantially to the length of the sputtering chamber. The distance between two consecutive substrates in the coating machine, the so-called "gap," must be as small as possible to prevent the target material from being sputtered in the coating machine. Typically, the gap is about 30 mm to 100 mm. With respect to the length of the substrate used for conditioning, the gap, that is, the distance between two consecutive substrates in the coating machine, must be at most about 1 / 8 to 1 / 12 of the length of the smallest substrate.

[0013] The minimum amplitude of vibration preferably corresponds substantially to the length of the sputtering chamber. The maximum amplitude of vibration is preferably the length of the moving chamber, and the provided coating machine is equipped with a buffer chamber, and the maximum amplitude can be enhanced to include the buffer chamber.

[0014] A heated conductance tunnel can be used to heat at least one pump compartment.

[0015] The length and / or vibration amplitude of the conditioning substrate are preferably selected so that only a single conditioning substrate is located within the sputtering chamber during vibration.

[0016] After conditioning the coating machine, the coating material can be recycled from the conditioning substrate.

[0017] During sputtering and / or heating, the desorbed water is preferably pumped out.

[0018] During conditioning, it may be desirable to temporarily stop the sputtering process at least once and at least partially discharge the coating machine into any dry gas or atmosphere such as Ar, O2, N2, or air. Subsequently, the conditioning process can be resumed by pumping the coating machine again and restarting sputtering.

[0019] The conditioning process is preferably stopped when it is determined that conditioning is complete by detecting that the remaining water partial pressure in the coating machine is below a predetermined threshold. Preferably, the water partial pressure in the coating machine is detected by using a residual gas analyzer and / or a spectroscopic plasma emission monitoring system.

[0020] The present invention further provides an apparatus for coating a substrate, and is particularly configured to perform the conditioning method described above. The apparatus comprises a processing area including at least one pump compartment and at least one sputtering compartment, and a driving means for moving a substrate through the processing area. The driving means is configured to move the substrate so that the substrate undergoes vibratory movement in the processing area during conditioning by sputtering and / or heating.

[0021] The device preferably further comprises a heating means, in particular a heated conductance tunnel, and / or means for determining water partial pressure.

[0022] According to the present invention, in order to combine the advantages of the conditioning procedure described above of the prior art and simultaneously address their disadvantages, the following procedure is proposed according to an embodiment of the present invention, wherein the entire coating machine process area, including potentially an inlet or outlet transfer chamber, is filled with glass of low quality or out-of-specification or any alternative substrate material providing high thermal capacity (preferably a metal substrate such as stainless steel or aluminum, for example). The coating machine is closed at both ends, pumped, and a sputtering process and / or alternative or additional heating means are operated to heat the coating machine. The substrate is now vibrated within the coating machine with an amplitude of the length of the transfer chamber or any other preferred amplitude.

[0023] In this way, the following advantages can be achieved: (1) The heat required for conditioning is provided by the operating sputtering process. (2) Glass or alternative substrate materials protect surfaces within the coating machine from being coated with the sputtered material, thereby reducing the aforementioned risk of debris. (3) Using vibration, the pump compartment adjacent to the process compartment is heated by the high-temperature substrate moving from the high-energy sputtering compartment to the "cold" pump compartment, which is not necessarily heated actively but is heated backward.

[0024] Since glass or alternative substrate materials are vibrating within the coating machine, the following disadvantages can be resolved: (1) Since the coating machine no longer leaves a vacuum, the energy supported by the substrate is not lost. Process heat accumulates in the substrate and is distributed to the colder areas of the coating machine (pump compartment), and consequently, the sputtering energy required for conditioning can be reduced without any adverse effect on the conditioning time. (2) There is no need to transfer the substrate material from the coating machine outlet back to the coating machine inlet. (3) The washing machine is not contaminated by particles removed from multiple coated conditioning substrates during the washing procedure. Therefore, no specific cleaning procedure is required for the washing machine.

[0025] If low-quality glass is used as a substrate during conditioning, it may be scraped off after the conditioning process. In the case of any metal sheets used, they may be cleaned (e.g., by sandblasting) and reused for the next conditioning process.

[0026] To avoid thermal stress on the substrate material, especially when glass is used as a conditioning substrate, it is advantageous to use glass sizes other than the jumbo length, most preferably glass sizes similar to the compartment length, which can be about 850 mm. Smaller dimensions may also be advantageous when using metal sheets, as smaller sizes can be handled more easily during loading and unloading processes and cleaning procedures (e.g., sandblasting).

[0027] To effectively recycle the precious material (e.g., silver) coated on the conditioning substrate, the substrate may be cut to specific dimensions and arranged so that only silver is deposited on a single substrate. After the conditioning process, these specific substrates may be sorted, and the deposited precious material may be recycled from the substrate surface. All other substrates may be cleaned by sandblasting.

[0028] As the sputtering process is utilized to provide the energy required for conditioning, the remaining disadvantage is the waste of the target material during the conditioning procedure, which is lost for production. This disadvantage can be resolved by using a heated conductance tunnel of any other heating means or heatable component within the pumping chamber or the coating machine, which effectively transfers heat to the conditioning substrate. If thermal energy can be transferred to the substrate material by the heated conductance tunnel or an alternative component, the sputtering process can be reduced for conditioning purposes or even stopped to completely remove the waste of the target material.

[0029] Ideally, the optimized conditioning procedure according to the present invention may be supplemented by an "alternating pumping and ventilation process." In the first alternating sequence, the substrate is heated by a sputtering process and / or by a heated conductance tunnel, and separated water is pumped out. In the second sequence, the sputtering process is stopped, and the coating machine partially ventilates with dry air or an alternative gas as described above, and subsequently pumps again, continuously heating the substrate by a heatable conductance tunnel and / or by the sputtering process as soon as the pressure is able to start the cathode.

[0030] Finally, the entire conditioning procedure, possessing all the described features and benefits, can be completed with a suitable endpoint detection for the remaining water partial pressure. A residual gas analyzer (RGA) can be applied for this purpose in the most relevant compartments (e.g., Ag prior to an adjacent Ag compartment, or the ZnO seed layer, the cooling pump compartment, or any other advantageous location in the coating machine). An effective alternative spectroscopic plasma emission monitoring system (PEM) can also be applied to monitor the relevant water emission wavelengths in the essential process compartments as long as the plasma is switched on. Any other system may be used for endpoint detection to sense the residual water partial pressure.

[0031] Hereinafter, the present invention will be described in more detail with reference to the drawings.

[0032] FIG. 1 illustrates a coating machine that performs a conditioning method according to the prior art.

[0033] FIG. 2 illustrates a coating machine that performs a conditioning method according to one embodiment of the present invention.

[0034] FIG. 3 illustrates a coating machine including a material processing compartment for performing a conditioning method according to one embodiment of the present invention.

[0035] FIG. 4 illustrates a coating machine comprising a pump compartment equipped with a heatable conductance tunnel for performing a conditioning method according to one embodiment of the present invention.

[0036] FIG. 1 illustrates a coating machine that performs a conditioning process as known in the prior art described above. The coating machine includes a processing area (1) composed of a loading and unloading compartment, a buffer / transfer compartment B / T, and a plurality of processing compartments (P). The processing area (1) is subdivided into a pump compartment and a sputtering compartment, which will be described later with reference to FIG. 2. As indicated by the arrow below the coating machine shown in FIG. 1, a sputtering process is performed in the processing area to heat and thereby condition the processing area while continuously moving an "infinite train" of substrates (5) through the processing area. According to the prior art, the substrate used when conditioning the coating machine corresponds to the substrate typically used to produce the coated substrate. However, the process of this prior art suffers from the aforementioned problems, such as energy consumption and the disposal of the coated material.

[0037] According to the present invention, as illustrated in FIG. 2, the substrate undergoes vibratory movement in the processing area (1) during conditioning, which is indicated by the arrow below the coating machine in FIG. 2. Preferably, the substrate vibrates within the coating machine with an amplitude corresponding to the length of the transfer compartment (T or BT). A specific conditioning substrate may be used during conditioning, which is, for example, a low-quality glass substrate or a metal substrate having sufficient thermal capacity. However, a conventional substrate typically used in a coating machine may be used in the same way during conditioning.

[0038] As shown in FIG. 2, the processing area (1) having a processing compartment (P) can generally be subdivided into a pump compartment (10) and a sputtering compartment (11). By operating the sputtering compartment (11), the (conditioning) substrate is heated, which then heats the processing area that is not actively heated during sputtering, i.e., the part of the pump compartment (10). This is indicated by a curved arrow inside the processing area, illustrating the flow of heat from the substrate area currently being sputtered to another compartment in the processing area. Alternatively, or additionally, heat may be introduced into the processing area during conditioning by using other heating means, such as a heatable conductance tunnel as described later with reference to FIG. 4.

[0039] During the sputtering process, separated water is pumped out of the processing area. To improve conditioning efficiency, sputtering may be temporarily stopped during conditioning to at least partially discharge the coating machine with dry air. Subsequently, to continue the conditioning process, the coating machine may be pumped again and the sputtering process may be continued.

[0040] To detect whether the coating machine is sufficiently conditioned, endpoint detection may be performed. This can be done by determining the remaining water partial pressure. As soon as the detected remaining water partial pressure drops below a predetermined threshold, conditioning can be stopped and the coating machine can be prepared for manufacturing. As described above, any suitable system and method for measuring the remaining water partial pressure may be applied.

[0041] During conditioning, the vibration amplitude of the substrate may correspond substantially to, for example, the length of the moving chamber (T), or even include a buffer chamber (B). As described with reference to FIG. 3 below, when sputtering with a substrate, a different amplitude or substrate length may be advantageous. To ensure that substantially the entire coating machine is filled with substrate during conditioning, the distance between subsequent substrates should be kept as small as possible. For example, a distance of about 30 mm to 100 mm or less of the minimum substrate length, or 1 / 8 to 1 / 12, may be appropriate.

[0042] To avoid thermal stress on the substrate material, especially when glass is used as a conditioning substrate, it is advantageous to use alternative glass sizes rather than the lengths typically used in large-area coating machines, and the most desirable glass size, similar to the compartment length, may be about 850 mm. Smaller dimensions may also be advantageous when metal sheets are used as conditioning substrates, as smaller sizes can be handled more easily during loading and unloading processes and cleaning procedures (e.g., sandblasting).

[0043] In addition to the illustration of FIG. 2, FIG. 3 illustrates a compartment (111) in which a coating having a precious material, such as silver (Ag), is performed in the example illustrated in FIG. 3. In this case, in order to effectively recirculate the precious material, the conditioning substrates are cut to specific dimensions and can be arranged such that only one substrate is coated with the precious material due to the specific length of the substrate, with a vibration amplitude that can be specifically adapted to the length of the substrate. After the conditioning process, only this specific conditioning substrate coated with the precious material is sorted, and the deposited precious material can be recirculated from the substrate surface. All other substrates can be cleaned, for example by sandblasting, reused, or simply scraped.

[0044] Since the sputtering process is used to provide the energy required for conditioning, the remaining disadvantage may be waste of the target material during the conditioning procedure, which is lost for production. This disadvantage can be resolved by using a heating means or a heatable component in the coating machine, which effectively transfers heat to the conditioning substrate, such as a heated conductance tunnel within the pumping compartment, as shown in FIG. 4. If thermal energy can be transferred to the substrate material by the heated conductance tunnel (101), the sputtering process can be reduced or even stopped for conditioning purposes, thereby completely removing waste of the target material. Generally, it is possible to install additional heating means inside the coating machine at any suitable location to introduce thermal energy for conditioning, in addition to or as an alternative to introducing heat by operating the sputtering process. The conductance tunnel is designed to provide a passage for the substrate from one processing compartment to another while simultaneously avoiding excessive process gas flow between the processing compartments. Therefore, the height of the conductance tunnel is minimized, so that the distance between the "tunnel roof" and the surface of the substrate is reduced. For this reason, the conductance tunnel (101) is a desirable component that provides effective heat transfer to the substrate when heated, as shown in FIG. 4.

[0045] According to the present invention, vibrating glass or an alternative substrate is arranged in a coating machine during conditioning, thereby reducing the risk of debris during manufacturing, maintaining the energy required for conditioning in the processing area, and simultaneously distributing it to the pumping compartment without heat loss to the atmosphere. To avoid excessive heat accumulated in the coating machine, sputtering power can be reduced, resulting in an energy-efficient conditioning process. Additionally, moving the substrate from the coating machine outlet to the coating machine inlet in the atmosphere can be avoided. Furthermore, contamination by coating particles in the washing machine, which is required according to the prior art for washing the coated substrate before reintroducing the coated substrate into the coating machine, can be avoided.

[0046] Compared to low-quality glass, a material with a higher heat capacity may be preferred as a conditioning material (e.g., stainless steel or aluminum) that can be cleaned by sandblasting after the conditioning process and reuse.

[0047] The substrate size (length) must be optimized to avoid thermal stress generated by heated and unheated areas on a single substrate, which can lead to substrate breakage in the case of glass. If metal sheets are used, there is no risk of breakage, but a smaller substrate will offer the advantage of easier handling (e.g., loading, unloading, cleaning).

[0048] The conditioning substrates are preferably arranged such that only one substrate vibrates under the material sputtering process. In this way, the deposited material can be efficiently recycled from that specific substrate after the conditioning process.

[0049] To provide conditioning heat by performing the sputtering process, a heatable conductance tunnel (101) or other heating means or heatable components may be applied in the coating machine as an additional or alternative to heating the conditioning substrate. In this way, waste of the sputtering material may also be removed.

[0050] The conditioning process can be completed by alternating pumping and aeration procedures: in the first sequence of alternation, the substrate is heated by a heatable conductance tunnel and the separated water is pumped out. In the second sequence, the coating machine is partially discharged by dry air or an alternative gas, which helps to separate the water more efficiently and is subsequently pumped out again, and the substrate is continuously heated by a heatable conductance tunnel.

Claims

Claim 1 A method for conditioning a coating machine to remove water and / or moisture from a processing area of ​​a coating machine, wherein the processing area (1) comprises at least one pump compartment (10) and at least one sputtering compartment (11), the method comprising: - loading a conditioning substrate (5) into the processing area (1) so that the processing area (1) is filled with a conditioning substrate (5); - conditioning the coating machine by starting a sputtering process in the processing area (1) and / or heating of at least one pump compartment (10), wherein during conditioning, the conditioning substrate (5) performs a vibrating movement in the processing area; wherein, during conditioning, sputtering is temporarily suspended and the coating machine is at least partially discharged with a drying gas and subsequently pumped again. Claim 2 A method for conditioning a coating machine according to claim 1, wherein the conditioning substrate (5) is a metal substrate having a specific heat capacity of at least 350 J / (kg*K), and the conditioning substrate (5) is cleaned and reused after conditioning the coating machine. Claim 3 In claim 1 or 2, the conditioning material (5) is low quality A method for conditioning a coating machine, wherein the glass substrate is a conditioning substrate and the conditioning substrate is scraped after conditioning the coating machine. Claim 4 A conditioning method for a coating machine according to claim 1 or 2, wherein the length of the conditioning substrate (5) corresponds to the length of the sputtering chamber (11). Claim 5 A conditioning method for a coating machine according to claim 1 or 2, wherein the distance between two consecutive substrates (5) in the coating machine is 30 to 100 mm. Claim 6 A conditioning method for a coating machine according to claim 1 or 2, wherein the minimum amplitude of the vibration corresponds to the length of the sputtering chamber (11). Claim 7 A conditioning method for a coating machine according to claim 1 or 2, wherein the heating means, the heated conductance tunnel (101), is used to heat at least one pump compartment. Claim 8 A conditioning method for a coating machine according to claim 1 or 2, wherein the length and / or vibration amplitude of the conditioning substrate (5) are selected such that only a single conditioning substrate (5) is located in the sputtering chamber (11) during vibration. Claim 9 A method for conditioning a coating machine according to claim 1 or 2, wherein the precious coating material is recycled from the conditioning substrate after conditioning the coating machine. Claim 10 A conditioning method of a coating machine according to claim 1 or 2, wherein separated water is pumped during sputtering and / or heating. Claim 11 delete Claim 12 A conditioning method for a coating machine according to claim 1 or 2, further comprising the step of stopping the conditioning when it is determined that the conditioning is completed by detecting that the remaining water partial pressure in the coating machine is less than a predetermined threshold. Claim 13 In claim 12, the water partial pressure within the coating machine is detected by using a residual gas analyzer and / or a spectroscopic plasma emission monitoring system. Claim 14 A substrate coating device comprising a processing area (1) including at least one pump compartment (10) and at least one sputtering compartment (11), and a driving means for moving a substrate (5) through the processing area (1), wherein the driving means is configured to move the substrate so that the substrate (5) performs vibratory movement in the processing area (1) during conditioning by sputtering and / or heating, wherein during conditioning, sputtering is temporarily suspended and the coating device is at least partially discharged with a drying gas and subsequently pumped again. Claim 15 In paragraph 14, the apparatus further comprises a heated conductance tunnel (101) and / or means for determining water partial pressure.

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