The invention relates to treatment systems for substrates and, more particularly, to a reactor for treating flat substrates.
EP 0312447 B1 has already disclosed a method for producing thin layers on substrates for electronic or optoelectronic use of one plasma deposition process (PECVD), wherein, in the presence of a deposition plasma, reaction gases for producing the layers are introduced into a plasma box arranged in a vacuum chamber. In this case, a pressure which is lower than that which prevails in the plasma box is generated and maintained in the vacuum chamber. Similar methods are also known from EP 02218112 B1 and U.S. Pat. No. 4,798,739. Further reactors, in particular comprising a plurality of chambers for the treatment of a substrate, are disclosed in DE 19901426 A1, U.S. Pat. No. 6,183,564 B1, U.S. Pat. No. 5,944,857, and also in the Japanese patent abstract JP 06267808 A.
The abovementioned PECVD method, which is used for the cost-effective production of solar cells with a high efficiency and wherein silane and hydrogen are used as process gases, has, as important deposition parameters, the gas pressure, the gas flow rate, the power density and frequency of the plasma excitation, the substrate temperature, the gas composition and also the distance between electrode and counterelectrode. In order to achieve high deposition rates, high gas flow rates and a reduction of the electrode distance are of importance here. In this case, favorable distances between the electrodes are in ranges between 0.5 and 15 mm. With such small distances, the introduction of the substrates into the space between the electrodes poses a problem, where it should be taken into consideration that ensuring high productivity with uninterrupted layer growth during coating necessitates parallel processing, for the realization of which cluster installations are used, which require a high structural outlay in the case of the substrate sizes of 1.4 m2 or more that are desired nowadays.
Central clusters are already known, wherein parallel-processing chambers are arranged around a central point, at which a central handling device is situated. What is disadvantageous about central cluster systems is that, in the case of large substrates, the central handling device becomes very large and not very accessible and that the number of process chambers and hence the throughput that can be achieved are limited. Vertical cluster installations are furthermore known, which are used in the production of TFT displays, for example. Vertical cluster systems comprise a tower-like architecture with flat process chambers, as a result of which effective gas separation between the components becomes difficult and the number of layers constructed one on top of another is limited.
The disclosure enables efficient plasma treatment of flat substrates, in particular the disclosure provides a corresponding reactor and a method for the treatment of flat substrates, and furthermore enables simple and reliable handling of flat substrates and also improved production of treated substrates.
The reactor according to the invention for the treatment of flat substrates comprising a vacuum chamber with a process space arranged therein, wherein a first electrode and a counterelectrode are provided for generating a plasma for the treatment of a surface to be treated and form two opposite walls of the process space, and means for introducing and means for removing gaseous material, in particular coating or cleaning material, into and/or from the process space, wherein the at least one substrate can be accommodated by the counterelectrode on the latter's front side facing the electrode, and a loading and unloading opening of the vacuum chamber, preferably with a closure device, is distinguished by the fact that provision is made of a device for varying the relative distance between the electrodes, wherein provision is made of a first, relatively large distance when loading or unloading the process chamber with the at least one substrate and a second, relatively small distance when carrying out the treatment of the at least one substrate, and/or provision is made of a device which is assigned to the counterelectrode and is intended for accommodating substrates, which is embodied in such a way that the at least one substrate is arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during the performance of the treatment, in particular the coating, preferably also during the loading or unloading of the process space, with the surface to be treated facing downward. In the context of the invention, the term flat substrates denotes, in particular, substrates for solar cells, glass panes or the like. Rectangular substrates of 1.4 m2 or more are typical. In the context of the invention, the term treatment denotes any manner of modifying a substrate by means of a plasma generated between two flat electrodes, but in particular a PECVD method.
Electrode and counterelectrode can advantageously be brought comparatively close together by means of the device for varying the distance, wherein the distance between the electrode and the substrate also decreases. As a result, the layer construction can advantageously be positively influenced during coating. It is conceivable to vary the distance and thus the process parameters during the treatment of the substrate as well, in order to supervise the treatment process. It goes without saying that in the case of varying the distance, either the electrode or the counterelectrode or both can be moved.
Furthermore, the substrate can advantageously be arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction during the performance of the treatment, with the surface to be treated facing downward. This reduces the risk of particle contamination of the sensitive substrate surface that is to be treated or has been treated, since fewer particles can reach said surface. Such particles arise if layers formed in the process space, for example layers composed of silicon, become chipped. Values of the angle alpha of 1°, 3°, 5°, 7°, 9°, 11°, 13°, 15°, 17°, 20°, 25°, 30°, 40°, 45° are preferred since the horizontal space requirement for the reactor is thereby reduced.
In the case of the handling device according to the invention for flat substrates comprising at least one gripping arm module for one or a plurality of substrates, it is provided that the gripping arm module is embodied in such a way that the substrates can be moved parallel to the surface thereof and are arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during the loading and unloading of a process space with a surface to be treated oriented downward. Contamination of the surface that is to be treated or has been treated while the substrates are handled is advantageously reduced by the substrates being arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction with a surface to be treated facing downward.
In further accordance with an exemplary embodiment, preference is given to a a control, sensors and a drive, and a position of a substrate relative to the electrode and/or counterelectrode of the reactor is determined by means of the sensors, and loading or unloading of the reactor or the vacuum chamber is carried out by means of control and drive.
A further aspect of the invention provides a device for processing flat substrates comprising a transport space extending along a longitudinal direction, at least one process container for the treatment of flat substrates, which is connected or can be connected to the transport space, and a transport robot for transporting substrates, which transport robot can be moved along the longitudinal direction, wherein it is provided that the process container and/or the transport robot are embodied in such a way that the substrates are arranged with the surface to be treated at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during a predefined time interval, preferably during the performance of any treatment of the substrates in the process container. The substrates are advantageously arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during a predefined time interval, preferably during the performance of a treatment the substrates in the process container or during the loading or unloading of the process container, with the surface to be treated facing downward, since, by this means, the contamination of the surface to be treated or of the treated surface can be reduced and, at the same time, the space requirement during the processing of the flat substrates can be kept relatively small. In this case, preference is given to a mount for the substrates without carriers (transport frames), since the latter are costly and unstable in the event of thermal loading. A certain stiffness of the substrates which permits the latter to stand on an edge is assumed in the case of such a mount.
A further aspect of the invention provides a method for the treatment of flat substrates in a reactor comprising a vacuum chamber with a process space arranged therein, wherein a first electrode and a counterelectrode are provided for generating a plasma for the treatment of a surface to be treated and form two opposite walls of the process space, and means for introducing and means for removing gaseous material, in particular coating or cleaning material, into or from the process space, wherein the relative distance between the electrodes is adjustable, and provision is made of a first, relatively large distance when loading or unloading the process chamber with the at least one substrate and a second, relatively small distance when carrying out the coating of the at least one substrate, and/or wherein the at least one substrate is arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during the performance of the treatment, in particular the coating, preferably also during the loading or unloading of the process space, with the surface to be treated facing downward.
A further aspect of the invention relates to a method for processing flat substrates with a transport space extending along a longitudinal direction, at least one process container for the treatment of flat substrates, which is assigned to the transport space, and a transport robot for transporting substrates, which transport robot can be moved along the longitudinal direction, wherein the process container and/or the transport robot make it possible for the substrates to form with the surface to be treated at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction at least during a predefined time interval, preferably during the performance of any treatment of the substrates in the process container.
The invention is described in greater detail below with reference to drawings, which also reveal further features, details and advantages of the invention independently of the summary in the patent claims.
The following explanation of reactors, handling, devices and methods for processing flat substrates will focus on structural aspects, where it is obvious to the person skilled in the art that these devices and methods are provided with sensors, heating and cooling units, control units and drives that are not specifically illustrated.
The electrodes 5, 7 form two opposite walls of the process space 9. The process space 9 is situated in a vacuum chamber 11 having a loading and unloading opening 49, which can be closed by means of a closure device 27. The closure device is optional. The vacuum chamber 11 is formed by a housing 13 of the reactor 1. Seals 15 are provided for the purpose of sealing off from the surroundings.
The vacuum chamber 11 can have any desired spatial form, for example with a round or polygonal, in particular rectangular, cross section. The process space 9 is embodied as a flat parallelepiped, for example.
For introducing and for removing gaseous material, means that are known per se are provided, wherein the gaseous material is coating or cleaning material, in particular. The cleaning material can be NF3, for example. The introduction and removal of the gaseous material can be effected both sequentially and in parallel.
In
According to the invention, the reactor 1 has a device for varying the relative distance between the electrodes, which device, in the embodiment in
The electrode 5 is arranged in a holding structure in the vacuum chamber 11, which is formed by the housing rear wall 33 in the illustration in
It can be seen in the illustration in
The reactor 1 in accordance with
According to the invention, a further embodiment provides for the counterelectrode 7 to have a device (not illustrated in
In
After the substrate 3 has been introduced into the reactor 1, the substrate 3 can be accommodated by the counterelectrode 7 on the latter's front side facing the electrode 5.
The device for accommodating substrates can be designed for substrates which are provided with a carrier.
In one embodiment of the invention, the device for accommodating substrates is designed for framelessly accommodating one or a plurality of substrates or for frameless carriers.
The device for accommodating substrates can furthermore be designed forchanging the distance between the substrate that is to be accommodated or has been accommodated and the surface of the front side of the counterelectrode. In particular, the substrate can be at a greater distance from said surface of the counterelectrode during the loading or unloading of the process space than during the performance of a treatment.
The device for accommodating substrates can have at least one upper holding element for one or a plurality of substrates at least in an upper edge region of the counterelectrode 7 and at least one lower holding element for one or a plurality of substrates at least in a lower region of at least the counterelectrode 7.
The lower holding element is embodied as a bearing element 115 for the lower edge of a substrate 105. In this case, the bearing element 115 is embodied as a bolt 118 with a metallic bearing part 116, which projects into the process space (not illustrated in
The upper holding element is embodied as a counterbearing 110 with a metallic counterbearing part 111 for an upper edge region of the substrate 105. The counterbearing is connected to a bolt 113 extending through a bushing in the counterelectrode 100 into a region of the vacuum chamber 11 on the rear side of the counterelectrode 100. Furthermore, an intermediate piece 112, preferably composed of a ceramic, is provided between counterbearing part 111 and the bolt 113. The bolt 113 can press against a stop 114 when the counterelectrode 100 is pulled back in the direction of the housing wall 120, and in the process can perform a movement relatively from the front-side surface of the counterelectrode 100. The distance between the substrate 105 and the front-side surface of the counterelectrode 100 can thus be increased. By means of the illustrated change in the distance between the substrate 105 and the surface of the front side of the counterelectrode 100, reliable loading and unloading of the process space becomes achievable since the substrate is spatially freed relative to the surface of the front side of the counterelectrode 100 during loading and unloading.
In one embodiment of the invention, furthermore, if the counterelectrode 100 is moved in the direction of the electrode for example in order to perform the treatment of a substrate, the holding elements which can be moved linearly relative to the surface of the front side of the counterelectrode are pressed against one or a plurality of stops situated for example in a coating-free edge region of a cutout in which the electrode is arranged. The distance between substrate and surface of the front side of the counterelectrode is thus reduced; the substrate is advantageously pressed against said surface, such that it is possible to achieve a fixing of the position of the substrate during the performance of the treatment. In a further embodiment of the invention, as an alternative or in addition, one or a plurality of holding elements is or are assigned to one or both side regions of the substrate.
Furthermore, the holding elements can be movable in a pivotable manner relative to the surface of the front side of the counterelectrode in order thus to facilitate a loading or unloading movement of the substrate.
Since defined potential conditions in the process space are important at least during the treatment, in particular during the performance of a coating, the holding elements are embodied in electrically floating fashion.
In the case of the handling device according to the invention for flat substrates comprising at least one gripping arm module, the gripping arm module is embodied in such a way that the substrates are arranged at an angle alpha in a range of between 0° and 90° relative to the perpendicular direction during the loading and unloading, of a process space for example, with a surface to be treated or a treating surface oriented downward. The angle alpha has a value of 1°, 3°, 5°, 7°, 9°, 11°, 13°, 15°, 17°, 20°, 25°, 30°, 40°, 45°.
The frame rack can be inserted into the shaft 350 and withdrawn therefrom parallel to the direction of the arrow 330. Furthermore, the handler assembly 300 has a second shaft 355 with a further frame rack (not visible). Analogously to the illustration in
The handling device according to the invention is assigned to a reactor according to the invention. In this case, the process space of the reactor is loaded or unloaded through a combination of a movement of the gripping arm parallel to the surface of the substrate to be introduced into the process space or to be removed therefrom, in a horizontal or vertical direction. As was described with reference to
In the case of a handling device comprising a first and a second gripping arm, a substrate treated in a reactor can be exchanged for a second substrate in a simple manner. In this case, a first substrate is unloaded from the reactor and introduced into the handling device, and a second substrate, already present in the handling device, is subsequently introduced into the reactor. In this case, only a movement of the handling device relative to the reactor is necessary in order to ensure a correct positioning of the gripping arm with respect to the loading and unloading opening.
A device according to the invention for processing flat substrates is illustrated in a sectional illustration in plan view in
In this case,
Situated in the, temperature-regulated, tunnel 420 is a robot 430, which, for clarification, is also illustrated at a second position in the tunnel 420, where it is designated by the reference symbol 430′. The robot 430 is arranged on a guide rail 435. Furthermore, two heating modules 450 and 455 are provided at the input of the processing line, wherein the heating module 450 enables heating at atmospheric pressure, for example. The process containers or reactors 410 are connected to the tunnel by valves 440. The tunnel 420 can be evacuated and/or can be filled with an inert gas, for example nitrogen or argon or the like. A reactor separate from the tunnel is designated by 415.
A processing line as in
In
It is advantageous, if sensors are provided, to determine the relative position of the handler arranged in the vacuum container and/or substrates assigned thereto with respect to the electrode or counterelectrode in a process container. A correct coupling for the loading and unloading of the process container with a substrate can then be controlled by means of a control.
Furthermore, provision is made of a device for varying the relative distance between the electrodes, wherein provision is made of a first, relatively large distance when loading or unloading the process space 520 with a substrate and a second, relatively small distance when carrying out the treatment of the at least one substrate.
The device for varying the relative distance between the electrodes comprises eccentrics 512, by means of which rotary drives 508 can bring about a parallel displacement of the counterelectrode 502. Furthermore, disk springs 506 are provided, which permit a wobbling movement of the counterelectrode 502, wherein the wobbling movement is limited by the eccentric drives 512. Furthermore, provision is made of a device which is assigned to the counterelectrode and is intended for accommodating substrates, which is analogous to the device already illustrated, but is not shown in detail in
The reactor 500 furthermore comprises a second vacuum chamber, in which a second process space is arranged, wherein provision is made of a second electrode and a second counterelectrode for generating a plasma for the treatment of a surface to be treated, which respectively form two opposite walls of the second process space. The second vacuum chamber with the second process space is embodied analogously to the first vacuum chamber with the first process space and is arranged on the rear side of the first electrode, that is to say on that side of the first electrode which is opposite relative to the first counterelectrode. Preferably, the second vacuum chamber is embodied in mirror-inverted fashion with respect to the first vacuum chamber. The second vacuum chamber furthermore comprises a device for varying the distance between electrode and counterelectrode. Furthermore, the reactor 500 comprises a radio-frequency feed 510, a housing strip 511, a ceramic stop 513, a housing door 514 and also seals 516 and vacuum bellows 517.
Number | Date | Country | Kind |
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10 2007 022 252.3 | May 2007 | DE | national |
10 2007 022 431.3 | May 2007 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/03414 | 4/28/2008 | WO | 00 | 6/8/2010 |