US20170362708A1 - Apparatus and method - Google Patents

Abstract

An apparatus and a method for processing a surface of a substrate exposes the surface of the substrate to alternating surface reactions of at least a first starting material and a second starting material according to the principles of atomic layer deposition method. A first starting material is fed on the surface of the substrate locally by a source by moving the source in relation to the substrate, and the surface of the substrate processed with the first starting material is exposed to a second starting material present in the atmosphere surrounding the source.

Description

BACKGROUND OF THE INVENTION
• The invention relates to an apparatus and a method for processing a surface of a substrate by exposing the surface of the substrate to alternating surface reactions of starting materials. Specifically, the present invention relates to an apparatus for processing a surface of a substrate by exposing the surface of the substrate to alternating surface reactions of at least a first starting material and a second starting material according to the principles of atomic layer deposition method. Particularly, the present invention relates also to a method for processing a surface of a substrate by exposing the surface of the substrate to alternating surface reactions of at least a first starting material and a second starting material according to the principles of atomic layer deposition method.
• Atomic Layer Deposition ALD method is based on deposition controlled by a surface, wherein the starting materials are conducted inside an ALD reactor onto the surface of the substrate one by one non-simultaneously and mutually separated. Traditionally starting material is brought onto the surface of the substrate in a sufficient amount so that all available binding sites of the surface will be in use. After each pulse of starting material the substrate will be flushed with inert gas so as to remove the excess of starting material steam in order to avoid the deposition from occurring in the gaseous phase. Then a chemisorbed monolayer of the reaction product of one starting material will remain on the surface. This layer reacts with the next starting material forming a partial monolayer of desired material. The reaction having occurred completely enough an excess amount of this second starting material steam will be flushed with inert gas, so the deposition is based on saturated surface reactions, i.e. the surface controls the deposition. According to a known technique the aforementioned ALD method will be carried in an ALD reactor in which the substrate to be processed is positioned.
• One problem in the arrangement according to above described prior art technique is that with ALD reactors it is not possible to process pieces which are so large that they do not fit inside an ALD reactor. This limits considerably the use of the ALD method in many applications. Another problem is that the ALD method is used according to a known technique with vacuum. When depositing for example inner surfaces of containers the container itself may form an ALD reactor in which the vacuum is provided. However, wall thickness of such containers is often not sufficient, and the container may not withstand the necessary vacuum and the container may collapse. Moreover feeding of starting materials successively into large chambers may be difficult and time consuming, since filling and emptying of large chamber is slow. Moreover all the surfaces of the substrate placed in the chamber will be exposed to surface reactions, whereupon it is not possible to expose only part of the surface of the substrate to surface reactions without mounting on the surface of the substrate masks which cover part of the surface of the substrate. However placing of such masks is often slow and complicated.
BRIEF DESCRIPTION OF THE INVENTION
• An object of the invention is thus to develop an apparatus and a method which solve the aforementioned problems. The object of the invention is solved by an apparatus that comprises one or more sources for feeding first starting material locally on a surface of a substrate, and in that the source is positioned in an atmosphere which comprises second starting material. The object of the invention is further achieved with a method that includes feeding on the surface of the substrate locally a first starting material by means of the source by moving the source in relation to the substrate and exposing the surface of the substrate processed with the first starting material to a second starting material present in the atmosphere surrounding the source.
• The preferred embodiments of the invention are object of the dependent claims.
• The invention is based on providing an apparatus, which comprises one or more sources for feeding first starting material locally on the surface of the substrate. The source may for example be a nozzle, nozzle head or like, which is adapted to feed a first starting material on the surface of the substrate. The first starting material reacts with the surface of the substrate forming a monolayer on the surface of the substrate. The source is provided movable in relation to the surface of the substrate so that by the source it is possible to sweep over the surface of the substrate or part of the surface by exposing this surface of the substrate left under the sweeping to a first starting material. The relative movement of the source and the substrate may be provided by moving uniquely the source or by moving uniquely the substrate or by moving both the substrate and the source relative to each other. According to the present invention the substrate and the source are positioned in an atmosphere which comprises second starting material. In other words the apparatus of the invention comprises feeding means for feeding second starting material to the atmosphere surrounding the source. Thus, when the surface of the substrate is exposed locally by means of the source to a first starting material, it will be exposed after having been swept by the source to a second starting material, which is present in the atmosphere surrounding the substrate. The second starting material reacts with the first starting material forming a monolayer on the surface of the substrate. This monolayer formed by the second starting material in turn reacts with the first starting material fed from the source upon next sweeping. Thus, the surface of the substrate may be processed locally by means of the source, when surface reactions occur on the surface of the substrate uniquely at the location which was swept by the source in order to expose the surface of the substrate to the first starting material.
• As described before, the number of sweeps performed with the source may serve to determine the desired number of deposition layers and thus for example the thickness of the desired deposition, because as a result of each sweeping there is formed one monolayer of first and second starting material on the surface of the substrate. Processing of a surface means in this application generally depositing a surface, alloying a surface layer and/or some other corresponding procedure for processing a surface or a surface layer. On the surface of the substrate means in this context both the external surface and the internal surfaces of a porous substrate, which are provided by the porosity.
• An advantage of the method and the apparatus of the invention is that it permits to use the ALD method also for processing surfaces of large pieces, which has not been possible earlier because of the dimensional limitation provided by ALD reactors. Moreover the present invention allows for local processing of such large pieces or surfaces, when processing of the whole surface is not desired or preferred, which has not been possible with prior art ALD reactors. Further, in the solution according to the present invention there is no need to use vacuum at all, or vacuum may be generated only at the location of the nozzle surface, whereupon thin-walled pieces are not exposed to vacuum, which might brake up the wall or collapse a thin-walled container. Moreover the present invention allows to process quickly large pieces with the ALD method and to use efficiently starting materials and possible flushing agents by minimizing the waste amount produced by the excess thereof.
BRIEF DESCRIPTION OF FIGURES
• The invention will now be described in further detail in connection with preferred embodiments, with reference to the accompanying drawings, in which:
• FIG. 1 shows schematically an embodiment of the apparatus according to the present invention;
• FIGS. 2A and 2B show schematically another embodiment of he apparatus according to the present invention;
• FIG. 3 shows schematically another embodiment of the apparatus according to the present invention;
• FIG. 4 shows schematically still another embodiment of the apparatus according to the present invention; and
• FIG. 5 shows schematically a side view of the apparatus according toFIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
• Referring toFIG. 1 a first embodiment of the apparatus of the present invention is shown. According toFIG. 1 the apparatus comprises asource6, which may be positioned on thesurface4 of thesubstrate2 to be processed. Thesource6 comprises a nozzle surface, which is placed against thesurface4 of thesubstrate2 to be processed or on thesurface4 within a distance from thesurface4 so that the nozzle surface will cover part of thesurface4 of thesubstrate2. Thus, the nozzle surface means in this context the surface of thesource6, which is placed against thesurface4 of thesubstrate2 or on thesurface4. By means of the source a first starting material A is conducted via nozzle surface on thesurface4 of thesubstrate2 at the region covered by the nozzle surface so that at this region covered by the nozzle surface thesurface4 of thesubstrate2 may be exposed to a first starting material A. The first starting material A may be fed together with a carrier gas, which carder gas may be an inert gas, which does not take part in the surface reactions on thesurface4 of thesubstrate2. According toFIG. 1, thesource6 comprises a startingmaterial space13, into which the first starting material A may be fed by means of gas feeding means14, which are in flow connection to the startingmaterial space13. Gas feeding means14 may comprise any connections, tubings, starting material inserts and similar means and parts which are needed in order to produce and feed the first starting material A into the startingmaterial space13. In the embodiment ofFIG. 1 agas delivery device16, such as an aperture plate or similar, is arranged in the upper part of the startingmaterial space13 in order to deliver uniformly the first starting material A originating from gas feeding means14 into the starting material space3. The startingmaterial space13 comprises an open wall or area, which opens to the nozzle surface forming astarting material zone10, from which the first starting material A fed into the startingmaterial space13 will gain connection with thesurface4 of thesubstrate2. In other words, according to the present invention first starting material A is able to discharge via thestarting material zone10 on the area of thesurface4 of thesubstrate2 which is covered by the nozzle surface and particularly below thestarting material zone10, thesource6 being placed against thesurface4 of thesubstrate2 or on thesurface4. The startingmaterial space13 of thesource6 thus forms an ALD reaction chamber with the part of thesurface4 of thesubstrate2 on which thesource6 is located. Then deposition of material according to the ALD method may occur at this part of thesurface4 of thesubstrate2 covered by the startingmaterial zone10 of thesource6 under the influence of the first starting material A. The nozzle surface of thesource6 may further be provided withbristles30, which surround thestarting material zone10 and protrude outwardly from the nozzle surface so that a slit will remain between the nozzle surface and thesurface4 of thesubstrate2. This slit together with thebristles30 allows the excess starting material fed into the startingmaterial space13 to exit from the startingmaterial space13 and at the same time the bristles allow thesource6 to be used also on surfaces thereof which comprise irregularities which are small or lower than the height of thebristles30. An underdosage or quasi underdosage may also be fed into the startingmaterial space13, whereupon substantially all of the first starting material A fed reacts with thesurface4 of thesubstrate2. When using an underdosage no additional first starting material A is able to flow outside the startingmaterial space13.
• According to the invention thesource6 is made movable so that it may be moved along thesurface4 of thesubstrate2, the nozzle surface being against thesurface4 of thesubstrate2 or on the surface within a distance therefrom. In other words, thesource6 is moved relative to thesubstrate2. Alternatively thesource6 may be stationary, and thesubstrate2, like the material web, is moved relative to thesource6, thesource6 being placed against or over thesurface4 of the substrate. Also both thesubstrate2 and thesource6 may be moved in order to obtain a relative movement. In yet another embodiment thesource6 may be placed against or over thesurface4 of thesubstrate2, lifted away from thesurface4 and transferred to the next place and repositioned against or over thesurface4 of thesubstrate2. Then thesource6 is not moved along the surface of the substrate but is placed at the desired location, removed and placed to the next location on thesubstrate2.
• Using thesource6 according toFIG. 1 it is possible to process thesurface4 of thesubstrate2 according to the ALD method by bringing by means of gas feeding means14 a first starting material A into the startingmaterial space13, thesurface4 of thesubstrate2 being exposed to a surface reaction provided by the first starting material B. By feeding the first starting material A at an underdosage relative to the capacity of thesurface4 of thesubstrate2 to bind starting materials, substantially all of the fed first starting material A will bind onto the surface3 of thesubstrate2, so that there is no need to flush the surface separately. In case of overdosage the first starting material A in excess will exit the nozzle surface throughbristles30 or the slit between the nozzle surface and thesurface4 of thesubstrate2. According toFIG. 1 thesource6 is positioned in a space theatmosphere1 of which comprises a second starting material B. This space which hasatmosphere1, may for example be a separate chamber or a room space or some other corresponding space in whichatmosphere1, which contains the second starting material B, may be maintained. The relative movement of thesource6 on thesurface4 of thesubstrate2 exposes thesurface4 to the first starting material A as the nozzle sweeps over thesurface4 and thesurface4 is exposed after sweeping to the second starting material B present in theatmosphere1 of the space, when the source no more covers the location of thesurface4 of thesubstrate2 which was swept by thesource6. Thus one sweep ofsource6 over thesurface4 of thesubstrate2 provides on thesurface4 one deposition layer of first and second starting material A, B in order to perform one complete ALD cycle. By feeding into the startingmaterial space13 an underdosage of first starting material A relative to the capacity of thesurface4 to bind starting material A the need of flushing thesurface4 may be eliminated, because all of the starting material A entering the surface via the startingmaterial zone10 binds to thesurface4. At the same time the carrying gas to be fed with the first starting material A flows through the bristles away from the nozzle surface by blowing away the second starting material B present in theatmosphere1 preventing it from entering below the nozzle surface. The movement rate of thesource6 relative to thesubstrate2 and the feeding rate of the first starting material A into the startingmaterial space13 may be dimensioned so that a desired underdosage state or other dosage state is obtained. Thus, by means of a reciprocating relative movement of thesource6 on thesurface4 of the substrate2 a desired amount of deposition layers may be obtained, with each sweeping of thenozzle6 one deposition layer is obtained. InFIG. 1, the reciprocating movement of the nozzle is illustrated by arrow M. The apparatus may also comprise two ormore sources6, which may be positioned for example on one another so that thesubstrate2 may pass below these sources and be exposed to the second starting material B present in theatmosphere1 between the sources.
• InFIGS. 2A and 2B there is shown a particular embodiment of the lamellar structured nozzle surface of thesource6. Thissource6 according toFIGS. 2A and 2B corresponds with its operation principles and applications substantially to the source ofFIG. 1, but in thissource6 according toFIGS. 2A and 2B there is a lamellar structure for feeding flushing agents as well as a suction for extracting the flushing agent and the starting materials. In the embodiment ofFIGS. 2A and 2B the nozzle surface contains a startingmaterial zone10, through which the first starting material A is fed on thesurface4 of thesubstrate2. InFIG. 2A there is shown a plan view of the nozzle surface, which comprises in the middle a startingmaterial zone10, to which first starting material A is brought by means of gas feeding means14. Startingmaterial zone10 is surrounded bysuction zone24, on which suction or vacuum is provided by means of suction means or vacuum means27, which are in flow connection to thesuction space19. Thesuction zone24 in turn is surrounded by flushingagent zone22, to which flushing agent is fed by means of flushing agent delivery means21. With this solution it is possible to obtain around the reaction space defined by the startingmaterial zone10 zones of inertgas valving type, which further allow using the first starting material A at an overdosage. InFIG. 2B there is shown schematically in side view the solution according toFIG. 2A. Thus, the first starting material A fed into the startingmaterial space13 by means of gas feeding means14 flows via the startingmaterial zone10 on thesurface4 of thesubstrate2, wherein the excess first starting material A and/or carrying gas fed into the starting material space will be drawn from the slit between nozzle surface and thesurface4 of thesubstrate2 into thesuction space19 and away from thesurface2 of thesubstrate2. At the same time flushing agent is fed by means of flushing agent feeding means21 into theflushing agent space23, which flushing agent flows via theflushing agent zone22 on the surface of the substrate and is further absorbed via thesuction zone24 into thesuction space19. By dimensioning suitably the feed pressure of the flushing agent, the efficiency of the feed pressure of the first starting material A as well as the surface areas of the flowing channels thereof, asource6 may be achieved, inside which a good vacuum is present and when at the same time it however neutralizes by means of the feeding rate of the first starting material A and the flushing agent the suction force generated by vacuum, wherein thesource6 may be moved easily on thesurface4 of thesubstrate2. Also in this embodiment the nozzle surface may be provided with bristles, which may be positioned around any one of thezones10,22,24 and when needed around more or all of thesezones10,22,24. Further it is to be noted that two or more of the lamellar structures according toFIGS. 2A and 2B may be provided on a nozzle surface, and between these lamellar structures there may be a slit or gap or corresponding space, which is in flow connection to theatmosphere1 in order to expose thesurface4 of thesubstrate2 between the lamellar structures to starting material B. This source according toFIGS. 2A and 2B may be used in the same manner as the source according toFIG. 1 by providing a relative movement between thesource6 and thesubstrate2.
• According to the invention the nozzle surface is provided so that thesource6 comprises a startingmaterial space13, which is in flow connection to the gas feeding means14, which startingmaterial space13 comprises a region opening to the nozzle surface of thesource6, which forms the startingmaterial zone10, through which the first material A is able to flow to thesurface4 of thesubstrate2, the nozzle surface being placed against and on thesurface4 of thesubstrate2 at a distance from thesurface4. Correspondingly theflushing agent space23 is in flow connection to the flushing agent delivery means21, which flushingagent space23 comprises an area opening to the nozzle surface of thesource6, which forms the flushingagent zone22, through which the flushing agent is able to flow to thesurface4 of thesubstrate2, the nozzle surface being placed against or over thesurface4 of thesurface2. Thesuction space19 is in flow connection to the suction means27, which suctionspace19 comprises an area opening to the nozzle surface, which area forms thesuction zone24, through which first starting material A and/or flushing agent may be drawn the nozzle surface being placed against or over thesurface4 of thesubstrate2, and/or thesuction space19, which provides vacuum between the nozzle surface of thesource6 and thesurface4 of thesubstrate2.
• Although the lamellar solution ofFIGS. 2A and 2B is shown as nested zones it may however be provided as successive zones. In other words thesource6 may comprise on the nozzle surface thereof in order to flush thesurface4 of thesubstrate2 at least oneflushing agent zone22 for conducting flushing agent to thesurface4 of thesubstrate2. The flushingagent zone22 may further be arranged successively in respect to the moving direction of thesubstrate2 or thesource6 with the startingmaterial zone10 and/or in the moving direction of thesource6 in front or rear side of the startingmaterial zone10. Likewise thesource6 may comprise in addition on the nozzle surface thereof at least onesuction zone24 for drawing the first starting material A and/or the flushing agent fed on thesurface1 of thesubstrate2 and/or for providing vacuum between the nozzle surface of thesource6 and thesurface4 of thesubstrate2. Thesuction zone24 may be arranged successively in relation to the moving direction of thesubstrate2 and thenozzle6 with the startingmaterial zone10 in the same manner as was described in connection with the flushingagent zone22, i.e. at the front or rear side or both sides of the startingmaterial zone10. Preferably thesuction zone24 is positioned between the startingmaterial zone10flushing agent zone22.
• InFIG. 3 there is shown a particular embodiment of the present invention, in which threesimilar sources7 are positioned over asubstrate2 moving in the direction of arrow N, for example a material web, so that the nozzle surface of thesource7 is against or over thesurface4 of thesubstrate2 at a distance from thesurface4. Thesources7 have in this embodiment a starting material feeding member3 with a round nozzle surface, which starting material feeding member3 is adapted to rotate about therotation axis15 or the center point thereof as described with the arrow P. The nozzle surface comprises a startingmaterial zone11, through which first starting material A may be fed on thesurface4 of thesubstrate2 in the same manner as in the embodiment ofFIG. 1. Thesources7 are again positioned in theatmosphere1, which contains second starting material B. Thesources7 feed on thesurface4 of the substrate a first starting material A and theatmosphere1 has a second starting material B, wherein thesurface4 would be exposed alternatively to starting materials A and B. The number of deposition layers available to thesurface4 of theweb2 and thus the thickness of the deposition layers may be controlled by means of the rotation speed of thenozzles6 and the moving rate of the web. Thesources7 and the starting material feeding members3 may also be provided with slits or corresponding zones (not shown), which are in flow connection to theatmosphere1 so that thesurface4 of thesubstrate2 may be exposed to surface reactions of the second starting material B present in theatmosphere1, the source rotating about thefirst rotation axis15. These slits may be provided for example in the gaps of startingmaterial zones11. Thefirst rotation axis15 extends in this embodiment substantially perpendicularly to thesurface4 of thesubstrate2 and is adapted to feed first starting material A substantially in the direction of thefirst rotation axis15 via the startingmaterial zone11.
• In case of a moving web as inFIG. 3, sources according toFIGS. 1, 2A and 2B could of course also be used, one of more of which could be placed over theweb2 and which could extend from one edge of theweb2 to another, wherein thewhole web2 would pass below thesource6. Such sources according toFIGS. 1 and 2 would be moved over a moving web reciprocally, whereupon the number of deposition layers would increase, when the surface of theweb2 would be exposed alternately to the first starting material A fed throughsource6 and to the second starting material B present inatmosphere1.
• InFIG. 4 there is shown a schematical side view of the source8 according to an embodiment of the present invention for feeding first starting material A on thesurface4 of thesubstrate2. The source8 is again positioned in theatmosphere1, which comprises second starting material B. The source8 comprises agas feeding member5 for feeding first starting material A on thesurface4 of thesubstrate2 as well as asecond rotation axis17, about which the gas delivery means5 is rotatable.Gas feeding member5 is preferably a cylindrical part which has substantially circular cross section. Alternatively thegas feeding member5 may also have a cross section of another shape, such as oval, triangle, square or some other polygonal shape. The length of thegas feeding member5 in the direction of thesecond rotation axis17 may vary according to each application and may be adapted to correspond substantially for example the width of the substrate, such as material web, being treated. It is essential, that the present invention is not limited to any single form ofgas feeding member5 but that thegas feeding member5 may be realized in any shape. However thegas feeding member5 is preferably rotationally symmetrical relative to thesecond rotation axis17. In addition, thesecond rotation axis17 is positioned to pass preferably along the centre axis of thegas feeding member5.
• Thegas feeding member5 is adapted to feed a first starting material A substantially in a transversal direction in relation to thesecond rotation axis17. According toFIG. 4 thegas feeding member5 is provided with one or more starting material zone(s)12, adapted to feed first starting material A. Thegas feeding member5 may also comprise one or more flushing agent zone(s) (not shown) for feeding flushing agent. In addition, thegas feeding member5 may be provided with one or more suction zone(s)31 for drawing and discharging first starting material A or flushing agent. According toFIG. 4, the startingmaterial zones12 and thesuction zones31 are provided to extend substantially in the direction of thesecond rotation axis17 of thegas feeding member5. In other words the startingmaterial zones12 and thesuction zones31 are longitudinal channels, which extend along the length of thegas feeding member5. Alternatively the startingmaterial zones12 and thesuction zones31 may also be shorter and may extend only a part of the length of thegas feeding member5, whereupon two or more of these may be present also in the direction of thesecond rotation axis17 successively in the same line.
• As described previously, first starting material A may be fed from thegas feeding member5 via the startingmaterial zone12 substantially transversally, perpendicularly or radially in relation to thesecond rotation axis17. Thegas feeding member5 may also comprise one or more flushing agent zone(s) (not shown) for feeding flushing agent on thesurface4 of thesubstrate2.
• Suction zones31 may be provided on thegas feeding member5 in the same manner as with the aforementionedstarting material zones12. By means ofsuction zones31 first starting materials A or flushing agents or both may be removed from thesurface4 of thesubstrate2 or proximity thereof.Suction zones31 are preferably provided to remove starting materials or flushing agents from thesurface4 of the substrate or proximity thereof substantially in transversal direction, perpendicular direction or radially in relation to the secondrotational axis17 of thegas feeding member5. By this source8 according toFIG. 4 thesurface4 of thesubstrate2 may be exposed to a first starting material A and at the same time by means of the suction zones an excess first starting material A may be drawn from thesurface4 of thesubstrate2. This source8 or thegas feeding member5 thereof may be moved also in horizontal direction, for example with a reciprocating movement over thesurface4 of thesubstrate2. The rotational movement of thegas feeding member5 about the secondrotational axis17 permits to feed quickly the first starting material A and thus combined to the horizontal movement to deposit quickly thesubstrate2, when the second starting material B is inatmosphere1. When thegas feeding member5 is positioned at a distance from the surface of thesubstrate2, the second starting material B is able to flow below thegas feeding member5 when the startingmaterial zone12 is not exactly towards the surface of thesubstrate2. By means of thesuction zones31 absorption of the second starting material B under thegas feeding member5 may be enhanced. Then thesurface4 of thesubstrate2 may be exposed both to the first and the second starting material A, B even though thegas feeding member5 is not moved in a horizontal direction relative to thesubstrate2.
• InFIG. 5 there is shown a schematic cross section of the source8 ofFIG. 4, which comprises agas feeding member5, which is rotatable about asecond rotation axis17. Thegas feeding member5 comprises several startingmaterial zones12 for feeding first starting material A. The startingmaterial zones12 and thesuction zones31 are preferably positioned alternately in the direction of the circumference of thegas feeding member5, as shown in the crosssectional view5. There may be one or moregas feeding zones12, and one or more, or none,suction zones31. The first starting material A may be fed in all cases alone or it may be fed by means of a carrier gas. Carrier gas may be fed together with the first starting material A so that the carrier gas carries the first starting material A on thesurface4 of thesubstrate2 however without participating in the surface reaction itself. The carrier gas is preferably an inert gas, like nitrogen, which does not react with the first starting material A.
• According toFIG. 5, thegas feeding member5 is adapted, according to arrows shown therein, to feed first starting material A substantially transversally or radially in relation to thesecond rotation axis17. Preferably thegas feeding member5 is adapted to feed first starting material A substantially in a perpendicular direction in relation to thesecond rotation axis17. In the simplest form of the present invention thegas feeding member5 comprises only one startingmaterial zone12, through which first starting material A may be fed. The source8 or thegas feeding member5 is preferably arranged so that thesecond rotation axis17 extends substantially in the direction of thesurface4 of thesubstrate2.
• In the embodiment ofFIG. 5 the source8 comprises asuction enclosure30, which provides asuction chamber35, which has suction apertures42. Thesuction enclosure30 further comprises aflow aperture50, which extends substantially in the direction of thesecond rotation axis17 of the gas feeding member and through which the first starting material A and any flushing agents are fed on thesurface4 of thesubstrate2 and respectively removed from thesurface4 of thesubstrate2. Theflow aperture50 is made narrow in the direction perpendicular to thesecond rotation axis17 relative to the diameter of thegas feeding member5 so that the fed first starting material A or flushing agent does not spread over a large area. In addition, thesuction enclosure30 is provided with a first and asecond flange52,54, which extend from the edge of theflow aperture50 in the direction of thesurface4 of thesubstrate2 away from theflow aperture5 according toFIG. 5 and along the length of thesecond rotation axis17 of thegas feeding member5.Flanges52,54 provide a diffusion barrier preventing the flow of gases from thefeed aperture50 to the environment and from the environment to theflow aperture50 however allowing thus thesurface4 of thesubstrate2 to be exposed efficiently to the first starting material A at the location of theflow aperture50. It is to be noted, that in certain embodiments the flange may also be provided to only one side of theflow aperture50.Flanges52,54 or one of them may be replaced by other type of diffusion barriers. Such a source comprising a suction enclosure does not allow the first starting material A to pass into theatmosphere1, which has a second starting material B, whereupon unwanted reactions of starting materials may be avoided. Such an enclosed source8 is preferably movable over thesurface4 of thesubstrate2 relative to the substrate so that thesurface4 of thesubstrate2 is exposed upon sweeping of source8 to the first starting material A and after the sweeping to the second starting material B present in the atmosphere.
• Above, with reference toFIGS. 1 to 5different sources6,7,8 are described, which are all adapted to expose locally thesurface4 of thesubstrate2 to a first starting material A. The facts described in connection with eachsource6,7,8 concerning the movement of the source or thegas feeding member3,5 thereof relative to the substrate and placing above the substrate are valid for allsources6,7,8. In addition, the apparatus according to the invention may comprise one ormore sources6,7,8 and they may be positioned in such a manner that thesubstrate2 is exposed to the second starting material present in theatmosphere1 between thesources6,7,8. Thesource6,7,8 may be positioned inside into a separate deposition chamber (not shown), which has anatmosphere1, which comprises the second starting material B. The deposition chamber may be provided so that the substrate or the substrates are brought through the deposition chamber or alternatively the substrate is placed inside the deposition chamber and the deposition chamber is closed for the processing time according to the batch process. Vacuum or overpressure may be inside the deposition chamber, or it may be at normal atmospheric pressure (NTP; 1 bar, 0° C.). Alternatively thesource6,7,8 is not positioned inside a separate deposition chamber but thesource6,7,8 is positioned directly in the room space, process space or in connection with another apparatus or chamber in which theatmosphere1 comprises a second starting material B. In a preferred embodiment, the apparatus comprises feeding means (not shown) for feeding second starting material B into theatmosphere1 surrounding thesource6,7,8, such as a deposition chamber, process space or other corresponding space. The feeding means may comprise a starting material container, a possible pump, a tubing for conducting the second starting material B into theatmosphere1 surrounding thesource6,7,8 or the deposition chamber as well as a feeding member, like a nozzle or other corresponding terminal device for feeding the second starting material B into theatmosphere1 or the deposition chamber. In a preferred embodiment the feeding means for feeding second starting material B are stationary and provided for example in the deposition chamber so that the second starting material may be fed in the deposition chamber through the wall thereof. In other words, the feeding means for feeding the second starting material B and thesource6,7,8 are separated in relation to each other and thus the feeding of the second starting material B is independent of the movement of thesource6,7,8 and the feedings of the first and the second starting material A, B are independent of each other. Thus the first starting material A is adapted to be fed via thesource6,7,8 locally on the surface of the substrate and the second starting material B is fed separately into theatmosphere1 surrounding thesource6,7,8 independently of thesource6,7,8 and separately thereof. This means that thesecond starting material1 is not fed according to the invention from thesource6,7,8. The second starting material B is thus not fed actively on the surface of the substrate and it, but the second starting material B is located, or is brought, only passively in the atmosphere surrounding thesource6,7,8, whereupon the surface of the substrate is exposed to the second starting material B continuously when it is not exposed to the first starting material A under the influence of thesource6,7,8.
• The apparatus according to the present invention for processing asurface4 of asubstrate2 by exposing thesurface4 of thesubstrate2 to alternating surface reactions of at least a first starting material A and a second starting material B according to the principles of atomic layer deposition method may comprise one or more of theaforementioned sources6,7,8. Thesource6,7,8 is adapted to feed a first starting material A locally on thesurface4 of thesubstrate2. The source is further positioned in theatmosphere1, which comprises second starting material B. Thesource6,7,8 is further adapted to be movable in relation to thesubstrate2 on thesurface4 thereof or in the proximity of thesource4 so that with thesource6,7,8 it is possible to sweep over thesurface4 by exposing locally thesurface4 at the same time to a first starting material. After the sweeping thesource6,7,8 moves away from the part of thesurface4 swept, whereupon the part of thesurface4 swept is exposed to the second starting material present in theatmosphere1. Exposure to starting materials A and B produces always a surface reaction on thesurface4 of thesubstrate2 according to the principles of the ALD method, In all of the embodiments of thesources6,7,8 described above thesource6,7,8 is adapted to be movable on thesurface4 of thesubstrate2 or in the proximity thereof in relation to the substrate (2) for performing the sweeping. This means that thesource6,7,8 may be moved on the surface of the substrate, thesubstrate2 may be moved in relation to astationary source6,7,8 or both thesource6,7,8 and thesubstrate2 may be moved. The movement of thesource6,7,8 may be a transferring movement occurring on a plane, a reciprocating movement or a rotating movement or a combination thereof. The apparatus according to the invention may comprise two ormore sources6,7,8, which are separated from each other by a slit or a space in flow connection with thesurrounding atmosphere1 in order to expose thesurface4 of thesubstrate2 to a second starting material B in between the sources. Alternatively eachsource6,7,8 may comprise or more startingmaterial zones10, which are separated from each other with a slit or a space in flow connection with thesurrounding atmosphere1 in order to expose thesurface4 of thesubstrate2 to a second starting material B in between the startingmaterial zones10. It is also possible to provide asource6,7,8, which comprises two or morestarting material members3,5, which are separated from each other by a slit or a space opening to thesurrounding atmosphere1 in order to expose thesurface4 of thesubstrate2 to a second starting material B in between the startingmaterial feeding members3,5.
• As starting materials A and B any starting materials typically used in the ALD method may be used. As a first starting material A for example TMA (trimethyl aluminium) may be used, and as the second starting material B water steam. In certain applications the second starting material B may be reactive or non reactive, air or oxygen. Alternatively the first and the second starting material A, B may also be plasma or radical or may be arranged to provide a sparkle.
• The present invention further relates to a method for processing thesurface4 of thesubstrate2 by exposing thesurface4 of thesubstrate2 to alternating surface reactions of at least a first starting material A and a second starting material B according to the principles of atomic layer deposition method. The method includes feeding on thesurface4 of thesubstrate2 locally a first starting material A by using thesource6,7,8 by moving thesource6,7,8 in relation to thesubstrate2, and exposing thesurface4 of thesubstrate2 processed with the first starting material A to a second starting material B present in anatmosphere1 surrounding thesource6,7,8. In other words, according to the present invention the second starting material B may be fed into theatmosphere1 surrounding thesource6,7,8, such as a deposition chamber, and thus to expose the surface of the substrate to the second starting material B. The second surface material B is fed into theatmosphere1 preferably independently of thesource6,7,8. In other words, the second starting material is fed preferably from one or more stationary feeding point(s) into theatmosphere1. Then the concentration of the second starting material B may be obtained stable in theatmosphere1 surrounding thesource6,7,8 independently of the movement of thesource6,7,8. This further ensures a stable deposition result. As described before, the feeding of the first feeding material A and the second feeding material B are independent of each other and the movement of thesource6,7,8. Further, it is to be noted that in every case the feeding of the second material B is not necessary, if for example humidity present in the air is sufficient as a second starting material B. The surface of the substrate is thus exposed actively by means of thesource6,7,8 to the first starting material A and passively to the second starting material B present in the atmosphere. The moving of thesource6,7,8 is performed in the method as described hereinbefore. Thus thesurface4 of thesubstrate2 is exposed alternately to the first starting material A fed by thesource6,7,8 and to the second starting material B present in theatmosphere1.
• Although several embodiments and features according to the present invention are described hereinbefore, all of which are not shown in the accompanied embodiment, it is clear that all of the features shown may be combined in order to provide in each case the preferred embodiment.
• It is clear to a person in the art that with technical developments the basic idea may be realized in many different ways. Thus the invention and the embodiments thereof are not limited to the examples shown hereinbefore but may instead vary within the frames of the claims.

Claims (19)

1. An apparatus for processing a surface of a substrate by exposing the surface of the substrate to alternating surface reactions of at least a first starting material and a second starting material according to the principles of atomic layer deposition method, wherein the apparatus comprises one or more sources for feeding the first starting material locally on the surface of the substrate and feeding means for feeding second starting material to atmosphere surrounding the one or more sources, and that the one or more sources are positioned in the atmosphere comprising the second starting material.

2. The apparatus according toclaim 1, wherein the source comprises one or more starting material zone(s), through which the first starting material is fed locally on the surface of the substrate.

3. The apparatus according toclaim 1, wherein the source is adapted to be movable on the surface of the substrate or in the proximity thereof in relation to the substrate.

4. The apparatus according toclaim 1, wherein the source is adapted to be rotated in relation to the surface of the substrate.

5. The apparatus according toclaim 4, wherein the source comprises a rotatable starting material feeding member, which comprises one or more starting material zone(s) for feeding first starting material on the surface of the substrate.

6. The apparatus according toclaim 5, wherein the starting material feeding member is adapted to be rotatable about the first rotation axis and to feed the first starting material substantially in the direction of the first rotation axis via the starting material zone.

7. The apparatus according toclaim 5, wherein the starting material feeding member is adapted to be rotatable about the second rotation axis and to feed the first starting material substantially transversely, radially or perpendicularly in relation to the second rotation axis via the starting material zone.

8. The apparatus according toclaim 1, wherein the substrate is adapted to be movable in relation to the source.

9. The apparatus according toclaim 3, wherein the source or the gas feeding member is adapted to be movable substantially with a reciprocating movement directed in accordance with the surface of the substrate on the surface of the substrate or in the proximity of the surface.

10. The apparatus according toclaim 1, wherein the source for conducting at least one flushing agent to the surface of the substrate for flushing of the surface of the substrate.

11. The apparatus according to claim wherein the source comprises at least one suction zone for drawing the first starting material or the flushing agent fed on the surface of the substrate or for providing vacuum between the source and the surface of the substrate.

12. The apparatus according toclaim 1, wherein the source comprises two or more starting material zones, which are separated from each other by a slit or space in flow connection to the surrounding atmosphere for exposing the surface of the substrate to the second starting material between the starting material zones.

13. The apparatus according toclaim 5, wherein the source comprises two or more starting material feeding members, which are separated from each other by a slit or space opening to the surrounding atmosphere for exposing the surface of the substrate to the second starting material between the starting material feeding members.

14. The apparatus according toclaim 1, wherein the apparatus comprises two or more sources, which are separated from each other by a slit or space opening to the surrounding atmosphere for exposing the surface of the substrate to the second starting material between the sources.

15. The apparatus according toclaim 1, wherein the apparatus comprises a deposition chamber, wherein the source is positioned and into which deposition chamber the atmosphere is provided.

16. The apparatus according toclaim 1, wherein the apparatus is adapted to function in normal atmospheric pressure or in vacuum.

17. The apparatus according toclaim 1, wherein the first or the second starting material is plasma or radical or is adapted to provide a sparkle.

18. The apparatus according toclaim 1, wherein the second starting material is reactive or non reactive.

19. The apparatus according toclaim 1, wherein the second starting material is air, water vapor or oxygen.

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