Title of Invention

METHOD FOR PRODUCING A DISK-SHAPED WORK PIECE ON THE BASE OF A DIELECTRIC SUBSTRATE

Abstract

Method for producing a disk-shaped work piece on the base of a dielectric substrate (100), which comprises treatment in a plasma processing chamber (PR) that is formed between two opposite electrode faces (2a;EF1, 2b;EF2) in a vacuum recipient, whereby an electrical high frequency field is generated between the electrode faces and thus in the processing chamber (PR) fed with a reactive gas a high frequency plasma discharge is created; one electrode face (2b, EF2) is made of dielectric material and to this a high frequency potential (Ø2b) with pre-given, varying distribution is applied along the face and the distribution of the electrical field in the plasma processing chamber (PR) is adjusted by the potential distribution (Ø2b) on the dielectric electrode face (2b, EF2), thereby the dielectric electrode face (2b, EF2) is formed with the substrate or the substrate is arranged on the metallically designed other (2a, EF1) electrode face, and further on the electrode face lying opposite to the substrate the reactive gas is introduced into the processing chamber (PR) from an opening (29), wherein the dielectric substrate (100) before treatment in the plasma processing chamber is coated at least section-wise with a coating material having a p for which there is valid: said coating being so that the resulting surface resistance Rs of said coating is: depositing said coated substrate on said metallic electrode surface (2a, EF1); establishing between said electrode surfaces an electric Rf field; inletting into said plasma processing chamber (PR) through a multitude of openings (29) in said one electrode surface, a reactive gas; establishing a locally varying electrical Rf potential along said one electrode surface; thereby etching or coating said substrate (100).

Full Text

Method for Producing a Disk-Shaped Work Piece on the Base of a Dielectric Substrate and a Vacuum Treatment Plant for This This invention is based on a method for producing a disk-shaped work piece on the base of a dielectric substrate that includes treatment in a plasma processing chamber that is formed between opposite electrode faces in a vacuum container. Definition As "electrode face" we define a surface that is freely subjected to the plasma processing chamber. In the mentioned method, on which the invention is based, an electrical high frequency field is generated between the electrode faces and thus a high frequency plasma discharge is created in the processing chamber fed with reactive gas. One electrode face is made of a dielectric material and a high frequency potential with pre-given, varying distribution is applied to it along the surface. The distribution of the electrical field in the plasma processing chamber is adjusted by potential distribution on the dielectric electrode face. In the method used as a basis, either the dielectric electrode face is formed with the substrate, or the substrate is arranged on the metallically designed second electrode face. Further, on the electrode face lying opposite to the substrate the reactive gas is introduced from an opening pattern into the processing chamber. In the last few years one is endeavouring more and more to produce larger disk-shaped work pieces using reactive, high frequency plasma-aided methods, among other things in order to reduce the production cost. Thus high frequency plasma-aided methods (PHfECVD) are used for substrate coating or as reactive high frequency plasma aided etching methods. The mentioned endeavour can be particularly recognized in the production of liquid crystal displays (LCD), TFT-displays or plasma-displays, as well as in areas of photo-voltage technology and particularly in the field of solar cells production. While conducting such production method with the help of the mentioned high frequency plasma supported reactive process using the known laminar metal electrodes lying parallel opposite to one another, each with a flat electrode face towards the processing chamber in a vacuum container, and applying the electrical high frequency field for plasma excitation, it was observed that when the substrate became larger and/or the exiting frequency fHf became higher, then the dimension of the vacuum container, in top view on the substrate, is no longer of subordinated significance. This is particularly with a view on the wave length of the used high frequency electromagnetic field in the vacuum. The distribution of the electrical high frequency field in the vacuum chamber, considered parallel to the electrode faces, becomes non-uniform and partly deviates significantly from an average value, which leads to a non-uniform treatment of the work piece positioned on one of the electrode faces: during etching one obtains a non-uniform distribution of the etching effect while coating, for example the layer thickness, the stoichiometry of the coating material etc. Such significant non-homogeneity in the treatment cannot be tolerated in some applications, like particularly in the production of the mentioned liquid crystals, TFT-or plasma displays, as well as in photovoltaic, and also particularly in the production of solar cells. The mentioned non-homogeneities are even more pronounced, the more the mentioned dimension or expansion of the container approaches the wave length of the electrical field in the container. For a solution to this problem, basically different principles are known: From the document US 6 631 692 and document US-A-2003/0089314 it is known how to form the plasma processing chamber between two opposite metallic electrode faces and thereby to shape one or both of the opposite lying metallic electrode faces. The metallic electrode face lying opposite the substrate lying on the other electrode face or the other metallic electrode face on which the substrate lies, or both opposite-lying metallic electrode faces are designed concave. This previously known process is schematically depicted in fig. 1, where: 1a and 1b: represent the opposite lying metallic electrode faces above the processing chamber PR, between which the high frequency field E is applied; Er, Ec: denote the corresponding peripheral and central electrical field generated. Another physically basic principle, on which the present invention is based in order to solve the above mentioned problem, has become known from the document US 6 228 438 of the same applicant who is filing this application. The principle of the procedure according to the document US 6 228 438 is first supposed to be described on the basis of fig. 2, which however depicts a version not published in the mentioned document. However, this is supposed to serve the purpose of basic comprehension. One of the opposite-lying electrode faces 2a is for example metallic, as shown. The second electrode face 2b, on the other hand, is made of dielectric material, e.g. a dielectric, laminar, thin plate 4. Along the dielectric electrode face 2b a potential distribution ϕ2b is created, which in spite of constant distance between both the electrode faces 2a and 2b in the processing chamber PR effects the desired local field distribution, as shown, e.g. in the edge region a stronger field Er than in the central region Ec. This can for example be realized as shown in fig. 2, in that a high frequency generator 6 is coupled through capacitive elements CR, CC differently on to the dielectric plate 4 corresponding to the desired distribution. In the design form of the principle used in fig. 2, which is however not published in the mentioned document US 6 228 438, the coupling capacities CR should be selected with greater capacitance value than the centre capacitance CC- The design of the capacitance CR or Cc is created according to the document US 6 228 438 in such a way as shown in fig. 3. A dielectric 8 is foreseen, that on the one hand forms the electrode face 2b as shown in fig. 2, which at the same time on account of the locally varying thickness d with respect to a metallic coupling face 10, forms the locally varying capacitances CR, c, as foreseen in fig. 2. The dielectric 8, as shown in fig. 4, can thereby be formed by solid body dielectric or by an evacuated or gas-filled hollow face 8a between the metallic coupling face 10 and a dielectric plate 4 forming the electrode face 2b. It is important that in the last mentioned hollow face 8a there is no plasma discharge. This invention is based on the already known procedure according to the document US 6 228 438 that is basically explained on the basis of fig. 2 to 4. In this procedure the question crops up as to where a substrate to be treated should be positioned in the processing chamber PR, on the dielectric electrode face 2b or on the metallic electrode face 2a. In the mentioned document US 6 228 438 it is taught how to deposit dielectric substrate on the electrode face 2b or electrode face 2a, as against (Kol. 5, Z. 35 ff.) substrate with electrically conducting surface on the metallic electrode face 2a. It is further known from the mentioned document, how to introduce reactive gas into the processing chamber, namely from an opening pattern distributed on the electrode face lying opposite to the substrate to be treated. If a dielectric substrate as shown in fig. 3 and 4 is deposited on the electrode face, then the opening pattern with the gas feeding channel should be provided on the side of the metallic electrode face 2a. If the substrate is arranged on the metallic electrode faces 2a, then the opening pattern for the reactive gas is provided on the side of the dielectric electrode face 2b. In that case, as one can obviously see in fig. 4, the hollow chamber 8a can be used as compensation chamber and the reactive gas can be first introduced through the metallic coupling arrangement with coupling face 10 into the compensation chamber 8a and through the opening pattern foreseen in the dielectric plate 4 into the processing chamber PR. However, it is also possible to fill the hollow space 8a with a dielectric solid, whether it is with the material forming the dielectric electrical surface 2b or one or more at least partially different ones and the opening pattern passing through this solid supplying the reactive gas through distributed pipes. One should basically assume that the combination of the opening pattern for introducing the reactive gas into the processing chamber and the dielectric 8 or 8a as shown in figures 3 or 4 on a single electrode array is much more complicated than providing the opening pattern on the electrode face 2a as shown in fig. 3 and depositing the substrate to be treated on the dielectric electrode face 2b, or even forming the dielectric electrode face 2b by a dielectric substrate itself. It seems to be advantageous to functionally separate the gas inlet arrangement with the opening pattern and the influencing measures for the electrical field, i.e. whenever possible to deposit the substrate to be treated on the dielectric electrode face, or to form the dielectric electrode face 2b at least partly by the substrate and to shape the gas inlet conditions through the opening pattern on the metallic electrode face 2a. It is the task of this invention to suggest a method for producing a disk-shaped work piece on the base of a dielectric substrate, with the help of which work pieces provided with a special coating can be produced by using the already known method from the document US 6 228 438. The thus produced disk-shaped work pieces should particularly be suitable for application as solar cells. This is achieved, in that the dielectric substrate is first coated with a coating material, at least section-wise, i.e. before treatment in the already mentioned high frequency plasma processing chamberwith specific resistance p: and having specific surface resistance Rs of the coating: then the coated substrate is positioned on the metallic electrode face and etched or coated in a reactively plasma-aided manner in the plasma processing chamber. As already mentioned, although in the already known procedure it was endeavoured to achieve a functional separation of gas inlet measures and field influencing measures and their allocation to respective. electrode faces due to design reasons, it has been seen that the combination of pre- coating the dielectric substrate with the mentioned coating and the basically known PHfECVD-method achieved success only when after the coating the substrate is deposited in the plasma processing chamber on the metallic electrode face and the field influencing measures as well as reactive gas inlet can be realised combined through the mentioned opening pattern in the region of dielectric electrode face. It was found out that after completing the coating of the dielectric substrate with a specific layer, only the mentioned substrate positioning leads to success and hence the function combination on the dielectric electrode face, initially considered as disadvantageous, has to be realised. With this suggested procedure one can also achieve a high flexibility with respect to the type of Hf-plasma-treatment. Irrespective of whether the dielectric substrate coated according to the procedure with the specified layer is etched or coated, and also irrespective of whether the coating is done by a PHfECVD- process dielectrically or electrically high conductively, the respective treatment process is not influenced, as far as the effect of the field distribution measures in the plasma 'processing chamber or the gas inlet measures are concerned. As already mentioned above, within the scope of this invention the dielectric substrate is first coated with a material whose specific electrical resistance p is significantly higher than materials that are traditionally described as "metallic" or "electrically conductive". Thus the specific resistances of traditional conductive materials like gold, silver, copper, aluminium lie in the range of 1.7 x 10-6 12cm 2.7 x 10-612cm. Definition The surface resistance Rs is obtained from the quotient of the specific resistance p and the layer thickness. It has the dimension Ω, indexed with the sign □ . The surface resistance Rs of a considered layer is dependent on the material as well as the thickness. According to this invention, it was found that the selection of method is not dependent on whether the surface of a dielectric substrate is pre-coated with electrically more conductive or electrically less conductive material, but decisively dependent on how the surface resistance Rs of the layer is in case of the mentioned material. In a design form of the method as per the invention the distribution of high frequency potential on the dielectric electrode face and the inlet of reactive gas into the processing chamber is realized, in that the dielectric electrode face is formed by a surface of a dielectric plate array towards the processing chamber, whose back side forms a chamber with its metallic coupling face, whereby the distance of the back side of the coupling face, along these faces varies and furthermore, the reactive gas is introduced into the chamber and then through the opening pattern provided in the plate array into the processing chamber. On the coupling face and the other electrode face that is electrically conductive, a high frequency signal is applied for plasma exciting. Due to the varying distance between metallic coupling face and back side of the dielectric plate array the capacitance distribution as shown in fig. 2 can be realized and the chamber space between this back side and the metallic coupling electrode face is simultaneously exploited as distribution chamber for the reactive gas that flows through the opening pattern in the dielectric plate array into the processing chamber. When we speak of "reactive gas" within the framework of this application, then we are also referring to a gas mixture with one or more reactive gases. The mentioned dielectric plate array, with view on fig. 2, forms with its capacitance value determined by its thickness, part of the coupling capacitances CR or Cc shown in fig. 2. Thus, in a design form, the dielectric plate array can be used with a pre-given variable thickness distribution. In another design form however, the dielectric plate array is used with an at least approx. constant thickness. In yet another design form, the potential distribution on the dielectric electrode face from the centre towards its periphery increasingly approaches the potential of the coupling face. This is achieved in the realization of the above mentioned chamber between metallic coupling and back side of the dielectric plate array, in that the reference distance in the periphery region is selected lesser than in the centre region and/or, in that the thickness of the dielectric plate array is designed lesser in the peripheral region than in the central region. The capacitance is selected lesser in the centre region than in the peripheral region. While designing this capacitance through a chamber (8a of fig. 4), it is for example done in the following way: a) the metallic coupling face is designed largely flat, the dielectric plate array largely with constant thickness and, considered from the process chamber, convex; b) the dielectric plate array is designed with largely constant thickness and flat, the coupling face, considered from the processing chamber, is concave; c) the coupling face is designed concave, the back side of the dielectric plate array also similarly and, considered from the processing chamber, the dielectric electrode face is concave; d) the coupling face is designed largely flat, the dielectric plate array with flat back side parallel to the coupling face and, considered from the processing chamber, with convex electrode face; e) the coupling face is designed flat, similarly also the electrode face, however the plate back side, considered from the processing chamber, is convex. If no chamber is foreseen, then for example, the coupling face and the electrode face can be parallel; the dielectric constant of the solid body dielectric lying in between can increase towards the periphery. It is apparent that for optimisation of the field distribution of the processing chamber, on the one hand, and the gas inlet direction distribution into the processing chamber, on the other hand, there is high flexibility. Although the field distribution measures and the gas distribution measures are carried out on the same electrode array, both magnitudes can be optimized. The procedures mentioned in the example can also be used in a mixed and combined manner. For example, the coupling face can be designed largely flat, the dielectric plate array with varying thickness and having, considered from the processing chamber, a concave back side and convex electrode face. Furthermore, it is clear to the expert that as a further design magnitude for the capacitance distribution explained in fig. 2, also the dielectric constant of the dielectric plate array or its distribution can be used. By selecting different materials along with the dielectric plate array the mentioned capacitance distribution and hence the potential distribution on the dielectric electrode face can be influenced additionally or alternatively to the distance variation or thickness variation. The dielectric electrode face can thereby be selected flat and parallel to the other electrode defining the processing chamber, in order to realize a plasma processing chamber of constant depth perpendicular to the electrode faces. This preferred designed form can be obtained, in that the metallic coupling face is designed concave considered from the processing chamber, the back side of the plate array is designed flat, or by designing the back side of the plate array convex when considered from the processing chamber, by making the coupling face flat, or by using materials of different dielectric constant along the dielectric plate array or electrode face; in the flat metallic coupling surface and additionally parallel flat plate back side, higher dielectric constant is used in the periphery region than in the centre region. If one considers that with the method as per the invention particularly large substrates with an expansion of their circumference of at least 0.5 m can be coated according to the invention and then subjected to Hf-plasma-treatment, then it is apparent that the above mentioned dielectric plate array with opening pattern and chamber formation is cumbersome. Therefore, in another design form the dielectric plate array is formed by ceramic tiles. These tiles can be mounted centrally with respect to the metallic coupling face and positioned at a distance. In this way the dielectric electrode face does not get deformed on account of thermal deformation of the tiles, which could have a negative influence on the field distribution and sometimes on the reactive gas feeding into the processing chamber. Furthermore, the tiles made of different materials with different dielectric constants, with different thicknesses and thickness profiles can be flexibly used for specific formation of desired plate properties and through mutual overlapping and multi-layered arrangement can be used for shaping concave or convex electrode faces or array back side. At this juncture it is once again emphasized that - if a chamber is formed - it is important to prevent that parasite plasma discharges occur in this chamber formed between metallic coupling face and the back side of the dielectric plate array, in which case the effect of this chamber as laminar distributed coupling capacitance would be negated. As is known to the expert, this is ensured by measuring the distance ratios between metallic coupling face and back side of the dielectric plate array, in any case lesser than the dark chamber distance valid from the respective process. In another design form of the method according to the invention, the distance of the plate array back side varies from the metallic coupling face in one step or preferably in several steps, and/or the thickness of the plate varies in one step or preferably in several steps. This design form is realized by using overlapping tiles for structuring the dielectric plate array, or if several tile layers are used with locally variable number of layers. In yet another design form, the distance of the plate array back side from the metallic coupling face varies constantly, and/or the thickness of the plate array varies constantly. This design is used if a largely flat dielectric plate array is used, with constant thickness and the metallic coupling face, considered from the processing chamber, is shaped concave. In another design form of the production method according to the invention, particularly for solar cells, the dielectric substrate, before treatment of the plasma processing chamber, is coated with electrically conductive oxide, preferably with electrically conductive and transparent oxide. This coating before the treatment can be done, for example, by reactive magnetron sputtering. It is further preferable if the dielectric substrate is coated with one of the following materials: ZnO, InO2, SnO, additionally doped or not doped, with a thickness D, for which the following is applicable: 10 nm Coating of the mentioned material within the given thickness range fulfils the layer properties given above with respect to specific resistance p and surface resistance Rs. The thus coated substrate is subsequently reactively etched and/or reactively coated by treatment in the plasma processing chamber. As reactive gas, preferably at least one of the following gases is used: NH3, N2, SF6, CF4, Cl2, O2, S2, CH4, silane, disilane, H2, phosphine, diboran, trimethylbor, NF3. For example, the following layers are deposited. Layer: Used reactive gas: Amorphous silicon SiH4, H2 (a-si) n-doped a-si (please see the original) micro-crystaline si For reactive etching, one uses for example SF6 mixed with O2 as reactive gas. The electrical high frequency field is additionally excited with frequency fFf, for which the following is applicable: 10 mhz or 13 mhz The produced work pieces further have a preferred circumference radius of at least 0.5 m. A vacuum treatment plant used within the scope of the method according to the invention has the following: • A vacuum container, and in it • A first flat-metallic electrode face; • A second dielectric electrode face towards the first that forms one surface of the dielectric plate array; • A metallic coupling face towards the back side of the dielectric plate array; • Electrical terminals on the coupling face and the first electrode face; • A gas pipe system that passes through the coupling face and a distributed pattern of openings through the plate array; and has a special feature that the plate array is formed by a several ceramic tiles. Design forms of the vacuum treatment plant according to the invention can become clear to the expert from the claims as well as the subsequent descriptions of the invention on the basis of the examples. The invention is described below in details on the basis of design examples and figures. The following are shown: Fig. 5 Schematically, on the basis of a functional block diagram, the sequence of the production method according to the invention; Fig. 6 In cross-sectional depiction, schematically and simplified, a design form of a vacuum treatment plant used within the scope of the method as per the invention; Fig. 7 Further simplified, the top view on a coupling face used in the plant as shown in fig. 6; Fig. 8 As reference example, over the diagonal expansion on a rectangular dielectric substrate, the resulting layer thickness distribution in case of PHFECVD-coating using traditional, flat metallic electrodes lying opposite to one another; Fig. 9 As reference example, analogous to the depiction in fig. 8, the distribution result on a dielectric substrate positioned directly above the concave shaped metallic electrode plate; Fig. 10 Further as reference example, analogous to the depiction in fig. 8 and 9, the result of the procedure as shown in fig. 9, however on a substrate coated with an InO2- layer as per the invention; Fig.11 The layer thickness-distribution profile obtained according to the method as per the invention; Fig. 12 Simplified and schematically, a plant as per the invention in another preferred design form used for conducting the method as per the invention; Fig. 13 A cut-out from the region shown in fig. 12 with "A", for explaining a further preferred design form; Fig. 14 In a depiction analogous to that of fig. 12, a further design form used as per the invention; Fig. 15 (a) to (f) Schematically a selection of possibilities by corresponding shaping of thedielectric plate array and the metallic coupling face, in the processingchamber to increase the electrical field peripherally; Fig. 16 Details and preferred assembly of a ceramic tile for formation of dielectric plate array in the metallic coupling face; and Fig. 17 Realisation of the possibilities shown in fig. 15 by structuring the dielectric plate with the help of ceramic tiles. Fig. 5 shows the sequence of the method as per the invention on the basis of a simplified block diagram. A dielectric substrate 100 is coated with a layer at a first vacuum coating station 102, e.g. station for reactive magnetron sputtering, whose material has a specific resistance p, and in such a way, that the resulting surface resistance Rs of the layer lies in the specific ranges The lower limit can go towards 0, because the surface resistance Rs is dependent on the thickness of the deposited layer. This thickness Ds of the layer is preferably selected as follows: especially as the deposited layer material is an electrically conducting oxide (CO), sometimes a transparent, electrically conducting oxide (TCO). For this, at least one of the following materials is deposited on the dielectric substrate: InO2, ZnO, Sn02, doped or not doped. Subsequently the coated dielectric substrate 104 is fed to a reactive Hf-plasma-treatment step at the station 105, namely a PHfECVD treatment step, or to a reactive Hf-plasma-aided etching step. The result is a work piece 106 that is particularly suitable for application as solar cells. The substrate 100 and hence also the resulting substrate 106 as per the invention thereby has a circumference radius Ru of at least 0.25 m, corresponding to a circumference of diameter 0.5 m, as shown in fig. 5 with the help of an arbitrarily shaped work piece W. Fig. 6 shows in cross-section and simplified, a first design form of a station or plant 105 as per the invention used according to fig. 5. A metallic vacuum container 105a has a flat basic surface 3 which pointing towards inner space and forms the first electrode face EF1. On this lies the substrate 104 made of dielectric material, coated - 7 - with the mentioned coating material. An electrode array 9 is mounted lying opposite to the substrate 104 provided with a coating 7 or opposite to the first electrode face EF1. It forms the second electrode face EF2. The second electrode face EF2, lying flat opposite to the electrode face EF1 in the shown example, is formed by the surface of a dielectric array 27. The back side ER of the dielectric array 27 along with a metallic coupling face KF forms a chamber 10. In the shown example the coupling face KF is designed as in-shape 10 which, considered from the processing chamber PR, is worked-in concave into a metal plate 14. The example of the in-shape 10 shown is, as shown schematically in fig. 7, rectangular and forms a distance distribution of the distance d between coupling face KF and back side ER of the dielectric plate array 27 that jumps sporadically from 0 to the constant distance in the recess 10. The substrate 104 is plotted in fig. 7 by a dashed line. Through the metal plate 14 a high frequency generator 13 is connected to the coupling face KF, which again is connected to the electrode face EF1 applied with reference potential in the usual way. From a gas storage 15, reactive gas GR or a reactive gas mixture, or if required, a working gas GA, e.g. argon, is fed through a distribution system 17 into a preliminary chamber 19 on the rear side of the plate 14. The pre-chamber 19 is bordered on the one side by a holder 18 insulating the plate 14 with respect to the container 105a, and on the other hand, formed by the back side of the plate 14 and the plant wall 21 of the container 105a towards the metallic electrode face EF1. The plate 14 has a pattern of gas pipe holes 25 passing through it. The gas pipe openings 25 in the plate 14 continue preferably aligned, in openings 29 through the dielectric plate array 27. The plate array 27 in this example-is made of a ceramic, e.g. Al2O3. With the help of the generator 13, over the coupling face KF, a high frequency plasma discharge Hf is created in the processing chamber PR. From the metallic coupling face KF through the laminar distributed capacitance C plotted by dashed line in fig. 6, a specific pre-given potential distribution is realized as already mentioned on the dielectric electrode face EF2. The exciting frequency fHf is selected as follows: 10MHz preferably 13 MHz The circumference diameter of the substrate 104 is at least 0.5 m and could very well go up to 5 m or more. The distance d in this design as shown in fig. 6 jumps from 0 to 1 mm. As already mentioned, on the basis of extension variants of the plant as per the invention to be explained later, the chamber 10 is not designed with a distance d jumping from 0 to a constant value, but the mentioned distance is optimally designed with a defined distribution, which also defines the decisive capacitance distribution. This distance d is selected frequency-dependent between 0.05 mm and 50 mm, so that no plasma can occur in the chamber 10. With the help of the generator 13 a power of 10 to 5000 W/m2 is fed per substrate face. For PHfECVD-coating of the substrate 104, as reactive gas preferably at least one of the following is used: NH3, N2, SF6, CF4, Cl2,O2, F2, CH4, silane, H2, phosphine, diboran, trimethylbor. The entire gas flow through the system 15, 17, and finally out of the openings 29 lies for example between 0.05 and 10 slm/m2 per m2 of substrate face. The above given magnitude hold good especially for reactive high frequency plasma- aided coating. For the following experiments the following settings were made: Process: PHfECVD-coating fHf: 27 MHz Substrate dimension: 1.1 x 1.25 m2 In-shape depth d according to fig. 6: 1 mm Total pressure: 0.22 mbar Power per substrate face: 280 W/m2 Substrate material: Float glass, with specific conductivity: 10-15 (Ωm)-1 Pre-applied coating: InO2, doped with tin. Surface resistance of the coating Rs: 3 Ω□ Reactive gas: silane with mixture of H2 Dilution of silane in H2: 50% Total gas flow per surface unit: 0.75 slm/m2. The experiments were done on the plant configurations as shown in fig. 6 or 7. In fig. 8, as reference result, the resulting layer thickness distribution measured in nanometers with respect to the layer thickness average value over both rectangular diagonals of the work piece is depicted, when in the array shown in fig.6 the plate 14 without in-shape 10 with a flat metallic face is directly used as electrode face lying opposite to electrode face EF1. In fig. 9, also as reference, there is an analogous depiction as in fig. 8 that shows the result, when on one side, as work piece to be coated, an uncoated dielectric substrate 100 is inserted, namely a float glass substrate as shown in fig. 5. As already shown for the measurement as in fig. 8, the plate 14 is designed without in- shape 10 and forms one of the electrodes in the processing chamber PR. On the other hand, an in-shape corresponding to the in-shape 10 is foreseen on the base surface 3 below the substrate. In a further analogous depiction and also as reference, fig. 10 shows the result, when on the plant configuration as already used for the results shown in fig. 9, i.e. with the in- shape 10 in the base surface 3, covered by the substrate and forming of the second electrode face through the flat surface of the plate 14 subjected to the processing chamber PR, the pre-coated substrate 104 is treated, namely the float glass substrate pre-coated with InO2. From that we thereby obtained the following: From fig. 8: that on account of the non-homogeneous field distribution in the processing chamber PR, the resulting coating thickness distribution is unacceptably non-homogeneous. - From fig. 9: that when the substrate to be treated is purely dielectric, the in-shape on the work piece bearing electrode (3) leads to a significant improvement of the field distribution homogeneity and hence to layer thickness distribution homogeneity. - From fig. 10: that the array that leads to a significant improvement of the layer thickness distribution for a purely dielectric work piece as in fig. 9, only when the work piece is made of a pre-coated substrate 104 according to the invention, and leads to a not acceptable layer thickness distribution. If however, according to the invention, the mentioned pre-coated substrate for example with the plant shown in fig. 6 is coated then one obtains good layer thickness distribution as shown in fig. 11. It is apparent that astonishingly in spite of the high specific resistance p of the layer material (InO2) only the suggested procedure according to the invention is suitable for achieving homogeneous effective distribution on the work piece. In fig. 8, further simplified and schematized, another preferred design form of the treatment step according to the invention or the plant 105 used for it as per fig. 5, is depicted. The pre-coated substrate 104 is again deposited on a flat first electrode face EF1. The metallic coupling face KF connected to the high frequency generator 13 is constantly shaped-in concave with respect to the processing chamber PR. The dielectric plate array 27 forms, on the one hand, the flat dielectric electrode face EF2 and of constant thickness and also similarly flat back side ER. Fig. 12 does not show the opening pattern through the dielectric plate array 27. The dielectric plate array 27 has a thickness D, for which the following holds good: 0.01 mm Definition In the context of this invention, by the term dielectric plate array we understand a laminar two-dimensional stretching dielectric form presenting itself as either foil type or right up to plate type. As the capacitance of the dielectric plate array 27 presents itself in series to the capacitance between coupling face KF and back side ER of the dielectric plate, the eventual large plate capacitance generated in case of thin dielectric plate array 27 would only have an insignificant influence on the small capacitance generated over the chamber 10a. Fig. 13 shows a cut-out of the array as per fig. 12, the way it is encircled at A. From that it is apparent that at least a part of the holes 25 through the metal plate 14a can align with the openings 29 (not shown) through the dielectric plate array 27 for the design form shown in fig. 12 as well as for all other design form as per the invention, and furthermore these have at least almost the same opening cross-sections. Although the coupling face KF in fig. 12 is always bent, it is easily possible to realize it by shaping in one step or in several steps. As material of the plate array 27 that is subjected to a high temperature load, an aggressive chemical atmosphere, high vacuum and plasma, as already mentioned, one can use a ceramic, e.g. Al2O3. Depending on the process, if required also other dielectric materials can be used, right up to high temperature resistant dielectric foils with the opening pattern. As shown in fig. 14, the mentioned dielectric plate array 27 can be replaced by several plate arrays 27a and 27b lying distanced above one another, which are mutually positioned by dielectric distance holders. All these individual plates 27a, 27b have the opening pattern analogous to the pattern of the openings 29 as shown in fig. 6 or 12 and 13. Their thickness can again be selected between 0.01 and 5 mm. Fig. 15 (a) to (f) show schematically possible mutual allocations of metallic coupling face KF and dielectric electrode face EF2, all of which leads to the fact that in the processing chamber PR, in the peripheral region, the electrical field gets strengthen with respect to the field in the central region. In fig. 15 (a) the metallic coupling face KF is flat. The dielectric plate array 27 is, with respect to the processing chamber PR, convex and of constant thickness V. On account of its metallic properties the coupling face KF with application of high frequency potential works as equi-potential face with ΦKF. In first approximation the array shown in fig. 15 (a) can be considered as follows: On each volume element dV along the chamber 10 there occur a series connection of a capacitance C10 and C27 as shown in the left side of the figure. While the capacitance C10 is defined by the varying distance between coupling face KF and back side ER of the dielectric plate array 27 as well as the dielectric constant of the gas in the chamber 10, the capacitance C27 is locally constant on account of the constant thickness V and the dielectric constant s of the plate array 27. "Usually the dielectric constant of the plate material is significantly greater than that of the gas in the chamber 10, whereby particularly for thin plate array 27 the capacitance C27 in series connection with C10 is negligible at least in first approximation. In the peripheral region of the dielectric electrode face EF2, C10 always becomes greater on account of the reducing distance d, whereby locally the potential distribution ϕEF2 along the electrode face EF2 while approaching the peripheral region also approaches the potential ΦKF of the coupling face KF. Thus above the processing chamber PR, in the peripheral region of the electrode face EF2 lies the almost total potential difference between ΦKF and the potential applied on the opposite electrode face EF2. In the centre region of the electrode face EF2, on account of the greater distance d C10 is lesser than in the peripheral region, whereby a greater high frequency voltage drops and thus the potential there ΦEF2 increasingly drops with respect to the potential ΦKF. Thus, above the processing chamber PR in this centre region there is a reduced electrical field as compared to the peripheral region. From the observation from fig. 15 (a) and taking into account that the chamber 10 is like a pressure compensation chamber for the reactive gas fed to the processing chamber PR from the opening pattern (not shown) through the dielectric plate array 27, it is apparent that by using a foil-type high temperature resistant plat array 27 the convex shape can be created on account of the pressure difference between processing chamber and chamber 10. In fig. 15 (b) the metallic coupling face KF continues to be flat. The dielectric plate array 27 has a convex shaped back side ER with respect to the processing chamber PR, however a flat electrode face EF2 parallel to the coupling face KF. On account of the usually higher dielectric constants ε of the material of the dielectric plate array 27, the capacitance C27 influences the capacitance C10 (see fig. 15 (a)) in the peripheral region only marginally in spite of increased thickness of the array 27, so that even in the design form as shown in fig. 15 (b) the locally varying capacitance C10 in series connection dominates and, as explained, the field distribution in the processing chamber PR got dominantly influenced. In the design form as shown in fig. 15 (c) the coupling face KF continues to be flat. The dielectric plate array 27 has a constant thickness, however it is formed by section-wise different materials with different dielectric constants sa to sd. Here one can do away with the chamber 10. Towards the periphery the dielectric constant ε of the plate material increases, whereby C27 increases with view on the substitute diagram in fig. 15 (a). In this design form the capacitance C10 formed through the chamber 10 is locally constant. If the constant thickness of the dielectric plate array 27 is selected sufficiently high, then the capacitance C27 in series connection with C10 getting bigger towards the peripheral region becomes dominant and one achieves the already described effect: in the edge region of the electrode face EF2 the electrical field in the processing chamber PR gets less weakened than in the central region, where C27 with εd is reduced with respect to C27 with εa. Fig. 15 (d) shows the already explained conditions according to fig. 6 or fig. 12. Fig. 15 (e) shows a flat coupling face KF. The dielectric plate 27 has a flat back side E parallel to the coupling face KF, however considered from the processing chamber PR it has a convex dielectric electrode face EF2. From the explanations given so far the expert can easily comprehend that in this way one can achieve the same field compensation effect in the processing chamber PR, as described so far, after giving the selected plate thickness and plate material dielectric constants. In fig. 15 (f) the coupling face KF as well as the electrode face EF2 is concave with respect to the processing chamber PR, however the back side ER of the plate array 27 is flat. If the dielectric constant of the plate array 27 is significantly greater than that of the gas in chamber 10, then here also C10 dominates and gives the desired field distribution in the processing chamber PR. From the fig. 15 (a) to (f) it is apparent that particular with respect to the shape of the dielectric electrode face EF2 there is high flexibility. The variants shown in fig. 15 can be further extended and combined, as the expert can easily comprehend, e.g. providing different materials on the plate array 27 combined with varying thickness etc., which increases the scope of design even further. As already mentioned one can dispense with the chamber 10 and realise the capacitance distribution exclusively through the plate array 27. If one considers that the reactive gas from the chamber 10 is introduced into the processing chamber through the opening pattern provided on the plate array 27 and further that the desired field compensation measures can be largely realized independent of the shape of the electrode face EF2 then it becomes apparent that simultaneously gas jetting direction into the processing chamber PR as well as field influence in the processing chamber PR can be optimized. While realizing the dielectric plate array 27 it should be taken into account that it is subjected to particularly high temperatures during the treatment process. Thus thermal expansion differences between dielectric plate array 27 and, through its fixation, the plate 14 forming the coupling face KF should be taken into account. It must also be kept in mind that with the described plant large and even very large substrates 104 are supposed to be treated. Realization of a dielectric plate array of this dimension and its assembly, so that in any case thermal expansions and contractions can be absorbed without deformation, poses problems if the array 27 is not foil-type but in the form of a solid dielectric plate, e.g. of ceramic like A12O3. In another design form preferred in this case, the fixed array 27 to be explained in fig. 16 is composed of several dielectrics, preferably ceramic tiles. Fig. 16 shows in top view and in cross-section such a tile and its mounting. The respective tile 50, preferably rectangular or square as shown, and made of a ceramic material like Al2O3 is centrally positioned with respect to the coupling face KF on the plate 104 with the help of a dielectric shim 54. Thus the relevant distance between the face KF and back side ER of the tiles 50 forming the plate array 27 is ensured. So that the tiles 50 are peripherally supported and with thermal load can still freely expand on all sides without stress, they are guided on support pins 56 with respect to the coupling face KF. The tiles 50 are secured against twisting by means of a guide pin 58 in an oblong channel 59. The tiles 50 are provided with the opening pattern (not shown in fig. 16) that if required is supplemented with crevices between the tiles 50. The tiles 50 could also overlap. One or more positions of such tiles can be foreseen, locally varying if required, and in different regions different ceramic materials with different dielectric constants can be used. In this way flexible, different shapes and material profiles can be realized in the dielectric plate array 27. Fig. 17 (a) to (f) schematically show the configurations as shown in fig. 15 (a) to (f), structured with tiles as explained in fig. 16. In this case only the tiles lying directly opposite to the coupling face KF have to be supported as shown in fig. 17; subsequent tile positions on the processing chamber side are mounted on the tiles lying below it. By looking at fig. 17 (a) to (f) the expert can easily understand how the mentioned tiles structure can be mounted in the configurations as shown in fig. 15 (a) to (f). In doing so, in the sense of the already mentioned opening pattern, a gas jetting into the processing chamber distributed to the desired extent has to be ensured, whether it is by utilizing the labyrinth channels remaining between the tiles and/or by providing additional holes or openings through the tiles 50 (not shown). The thickness of the ceramic tile DK should ideally be selected as With the production method as per the invention or the plant used as per the invention one can homogeneously coat large or even very large dielectric substrates first with special conductive layers and then surface-treat or coat by means of reactive, high frequency plasma aided methods, whereby particularly large to very large solar cells can be produced on a large industrial scale. WE CLAIM 1. Method for producing a disk-shaped work piece on the base of a dielectric substrate (100), which comprises treatment in a plasma processing chamber (PR) that is formed between two opposite electrode faces (2a;EF1, 2b;EF2) in a vacuum recipient, whereby an electrical high frequency field is generated between the electrode faces and thus in the processing chamber (PR) fed with a reactive gas a high frequency plasma discharge is created; one electrode face (2b, EF2) is made of dielectric material and to this a high frequency potential (Ø2b) with pre-given, varying distribution is applied along the face and the distribution of the electrical field in the plasma processing chamber (PR) is adjusted by the potential distribution (Ø2b) on the dielectric electrode face (2b, EF2), thereby the dielectric electrode face (2b, EF2) is formed with the substrate or the substrate is arranged on the metallically designed other (2a, EF1) electrode face, and further on the electrode face lying opposite to the substrate the reactive gas is introduced into the processing chamber (PR) from an opening (29), wherein the dielectric substrate (100) before treatment in the plasma processing chamber is coated at least section- wise with a coating material having a p for which there is valid: said coating being so that the resulting surface resistance Rs of said coating is: depositing said coated substrate on said metallic electrode surface (2a, EF1); establishing between said electrode surfaces an electric Rf field; inletting into said plasma processing chamber (PR) through a multitude of openings (29) in said one electrode surface, a reactive gas; establishing a locally varying electrical Rf potential along said one electrode surface; thereby etching or coating said substrate (100). 2. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 1, wherein, distribution of the high frequency potential and introduction of reactive gas into the processing chamber is carried out, in that the dielectric electrode face (EF2) is formed by a surface of a dielectric laminar array (27) towards the processing chamber, whose back side (ER) forms a chamber (10) with a metallic coupling face (KF), whereby the distance (d) of the back side (ER) from the coupling face (KF) varies along these faces and/or the thickness (D) of the laminar array (27) varies along these faces and/or the dielectric constant of the laminar array (27) varies along these faces, and further the reactive gas is introduced into the chamber (10) and through the opening (29) in the laminar array (27) is introduced into the processing chamber (PR), whereby between the coupling face (KF) and the other metallic electrode face (EFi), the high frequency (Rf) signal is fed. 3. Method for producing a disk-shaped work place on the base of a dielectric substrate as claimed in claim 2, wherein the dielectric laminar array (27) is used with an at least almost constant thickness (D). 4. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 2, wherein the dielectric laminar array (27) is used with a pre-given, varying thickness distribution. 5. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 4, wherein the potential distribution (Ø2b) on the dielectric electrode face (2b, EF2) varies from the potential on the coupling face (KF) more in the centre than in the peripheral region. 6. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 2, wherein the potential distribution on the dielectric electrode face (EF2), starting from the centre and progressing towards its periphery, approaches to the potential of the coupling face (KF), in that the distance between the back side (ER) of the laminar array (27) and the coupling face (KF) is selected lesser on the periphery than in the centre region and/or the thickness of the dielectric laminar array (27) in the peripheral region is selected lesser than in the centre region, and/or the dielectric constant of the material of the laminar array (27) is selected greater in the peripheral region than in the central region of the dielectric electrode face. 7. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 6, wherein a) the coupling face (KF) is designed largely flat, the dielectric laminar array (27) with largely constant thickness (D) and convex when considered from the processing chamber; or b) the dielectric laminar array (27) with largely constant (D) thickness is designed flat, the coupling face (KF) is concave when considered from the processing chamber; or c) the coupling face (KF) is designed concave, the dielectric laminar array (27) with flat back side (ER) and, considered from the processing chamber, a concave dielectric electrode face; or d) the coupling face is designed largely flat, the dielectric laminar array with flat back side parallel to the coupling face and, considered from the processing chamber, with convex electrode face; or e) the coupling face is designed flat, so also the electrode face and, considered from the processing chamber the back side of the laminar array convex. 8. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 2 to 7, wherein the dielectric laminar array (27) is formed by dielectric, preferably ceramic tiles (50). 9. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 8, wherein at least one part of the ceramic tiles (50) is mounted centrally with respect to the metallic coupling face (KF) positioned at a distance (52). 10. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 2 to 9, wherein the distance of the back side (ER) of the laminar array (27) varies from the metallic coupling face (KF) in one or preferably more stages and/or the thickness (D) of the laminar array (27) varies in one or preferably more stages. 11. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 2 to 9, wherein the distance of the back side (ER) of the laminar array (27) constantly varies from the metallic coupling face (KF) and/or the thickness of the laminar array constantly varies. 12. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 11, wherein the dielectric substrate (100) is first coated with an electrically conductive oxide and then (104) subjected to treatment in the plasma processing chamber. 13. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 12, wherein as conductive oxide a transparent one is selected. 14. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 11, wherein the dielectric substrate (100) is coated with at least one of the materials ZnO, InO2, SnO2, doped or not doped, and subsequently subjected to treatment in the plasma processing chamber (PR). 15. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 14, wherein the dielectric substrate before treatment in the plasma processing chamber is coated with a layer of coating material, for whose thickness Ds the following is applicable: 16. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 15, wherein the reactive gas contains at least one of the gases NH3,N2,SF6,CF4,Cl2,O2,F2,CH4, silane, disilane, H2, phosphine, diboran, trimethylbor, NF3. 17. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 16, wherein the high frequency field is excited with a frequency fuf for which the following is applicable: preferably 18. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claims 1 to 17, wherein the peripheral diameter of the substrate is at least 0.5 m. 19. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 2, wherein the chamber is filled with solid body dielectric. 20. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 19, wherein the solid body dielectric, with respect to its dielectric constant, varies along the dielectric electrode face. 21. Method for producing a disk-shaped work piece on the base of a dielectric substrate as claimed in claim 19, wherein as solid body dielectric the dielectric electrode face is used. ABSTRACT TITLE : "METHOD FOR PRODUCING A DISK-SHAPED WORK PIECE ON THE BASE OF A DIELECTRIC SUBSTRATE" Method for producing a disk-shaped work piece on the base of a dielectric substrate (100), which comprises treatment in a plasma processing chamber (PR) that is formed between two opposite electrode faces (2a;EF1, 2b;EF2) in a vacuum recipient, whereby an electrical high frequency field is generated between the electrode faces and thus in the processing chamber (PR) fed with a reactive gas a high frequency plasma discharge is created; one electrode face (2b, EF2) is made of dielectric material and to this a high frequency potential (Ø2b) with pre-given, varying distribution is applied along the face and the distribution of the electrical field in the plasma processing chamber (PR) is adjusted by the potential distribution (Ø2b) on the dielectric electrode face (2b, EF2), thereby the dielectric electrode face (2b, EF2) is formed with the substrate or the substrate is arranged on the metallically designed other (2a, EF1) electrode face, and further on the electrode face lying opposite to the substrate the reactive gas is introduced into the processing chamber (PR) from an opening (29), wherein the dielectric substrate (100) before treatment in the plasma processing chamber is coated at least section-wise with a coating material having a p for which there is valid: said coating being so that the resulting surface resistance Rs of said coating is: depositing said coated substrate on said metallic electrode surface (2a, EF1); establishing between said electrode surfaces an electric Rf field; inletting into said plasma processing chamber (PR) through a multitude of openings (29) in said one electrode surface, a reactive gas; establishing a locally varying electrical Rf potential along said one electrode surface; thereby etching or coating said substrate (100).

Documents:

03523-kolnp-2006-abstract.pdf

03523-kolnp-2006-claims-1.1.pdf

03523-kolnp-2006-claims.pdf

03523-kolnp-2006-correspondence other.pdf

03523-kolnp-2006-correspondence others-1.1.pdf

03523-kolnp-2006-correspondence-1.2.pdf

03523-kolnp-2006-description (complete).pdf

03523-kolnp-2006-drawings.pdf

03523-kolnp-2006-form-1.pdf

03523-kolnp-2006-form-2.pdf

03523-kolnp-2006-form-3.pdf

03523-kolnp-2006-form-5.pdf

03523-kolnp-2006-international publication.pdf

03523-kolnp-2006-international search authority report.pdf

03523-kolnp-2006-other.pdf

03523-kolnp-2006-pct others.pdf

03523-kolnp-2006-priority document-1.1.pdf

03523-kolnp-2006-priority documents.pdf

3523-KOLNP-2006-(10-02-2012)-CORRESPONDENCE.pdf

3523-KOLNP-2006-(10-02-2012)-FORM-1.pdf

3523-KOLNP-2006-(10-02-2012)-FORM-2.pdf

3523-KOLNP-2006-(10-02-2012)-FORM-3.pdf

3523-KOLNP-2006-(10-02-2012)-FORM-5.pdf

3523-KOLNP-2006-(10-02-2012)-FORM-6.pdf

3523-KOLNP-2006-(10-02-2012)-PA-CERTIFIED COPIES.pdf

3523-KOLNP-2006-(11-04-2012)-ABSTRACT.pdf

3523-KOLNP-2006-(11-04-2012)-AMANDED CLAIMS.pdf

3523-KOLNP-2006-(11-04-2012)-AMANDED PAGES OF SPECIFICATION.pdf

3523-KOLNP-2006-(11-04-2012)-CORRESPONDENCE.pdf

3523-KOLNP-2006-(11-04-2012)-DESCRIPTION (COMPLETE).pdf

3523-KOLNP-2006-(11-04-2012)-DRAWINGS.pdf

3523-KOLNP-2006-(11-04-2012)-OTHERS.pdf

3523-KOLNP-2006-(11-04-2012)-PA.pdf

3523-KOLNP-2006-(13-03-2013)-ABSTRACT.pdf

3523-KOLNP-2006-(13-03-2013)-AMANDED PAGES OF SPECIFICATION.pdf

3523-KOLNP-2006-(13-03-2013)-CLAIMS.pdf

3523-KOLNP-2006-(13-03-2013)-CORRESPONDENCE.pdf

3523-KOLNP-2006-(13-03-2013)-DRAWINGS.pdf

3523-KOLNP-2006-(13-03-2013)-FORM-1.pdf

3523-KOLNP-2006-(13-03-2013)-FORM-2.pdf

3523-KOLNP-2006-(13-03-2013)-FORM-3.pdf

3523-KOLNP-2006-(13-03-2013)-FORM-5.pdf

3523-KOLNP-2006-CORRESPONDENCE 1.1.pdf

3523-kolnp-2006-form 18.pdf

3523-KOLNP-2006-GRANTED-ABSTRACT.pdf

3523-KOLNP-2006-GRANTED-CLAIMS.pdf

3523-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3523-KOLNP-2006-GRANTED-DRAWINGS.pdf

3523-KOLNP-2006-GRANTED-FORM 2.pdf

3523-KOLNP-2006-GRANTED-SPECIFICATION-COMPLETE.pdf

3523-KOLNP-2006-MISCLLENIOUS.pdf

3523-KOLNP-2006-PETITION UNDER RULE 137.pdf

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