Method for coating a substrate

A method for subjecting a surface of a substrate to successive surface reactions of precursors according to the principles of atomic layer deposition includes subjecting the surface of the substrate to the first precursor in a first precursor zone and subjecting the surface of the substrate to the second precursor in a second precursor zone, changing the first precursor in the first precursor zone to a subsequent precursor which is different than the first and second precursors, subjecting the surface of the substrate to the subsequent precursor in the first precursor zone, and subjecting the surface of the substrate to the second precursor in the second precursor zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Entry of PCT International Application No. PCT/FI2017/050497 filed Jun. 30, 2017, which claims priority to Finnish Patent Application No. 20165543, filed on Jun. 30, 2016, the disclosure of each application is expressly incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a method and an apparatus for subjecting a surface of a substrate to successive surface reactions of at least a first precursor, a second precursor and a subsequent precursor according to the principles of atomic layer deposition for forming on the surface of the substrate a coating comprising two or more different coating layers.

BACKGROUND OF THE INVENTION

Atomic layer deposition (ALD) is conventionally carried out in a reaction chamber under vacuum conditions. One or more substrates are first loaded into the reaction chamber and then vacuum is provided or sucked into the reaction chamber and the reaction space inside the reaction chamber is heated to process temperature. The atomic layer deposition is then carried out by supplying and pulsing first and second gaseous precursors into the reaction chamber alternatingly and repeatedly for providing a coating layer with desired thickness on the surface of the substrate. A full ALD cycle, in which the first and second precursor are supplied into the reaction chamber comprises: supplying a pulse of first precursor into the reaction chamber, purging the first precursor from the reaction chamber, supplying a pulse of second precursor into the reaction chamber and purging the second precursor from the reaction chamber. Purging precursors may comprise discharging the precursor material from the reaction chamber, supplying purge gas, such as nitrogen, into the reaction chamber and discharging the purge gas. When desired number of ALD cycles and thus a desired coating layer thickness is reached, the vacuum in the reaction chamber is released and the substrates are unloaded from the reaction chamber. Then the same process is repeated for the next substrates.

An alternative way of providing coating layers on a substrate with ALD is using movable nozzle head which comprise at least one first precursor nozzle for supplying first precursor on the surface of the substrate, at least one second precursor nozzle for supplying second precursor on the surface of the substrate and at least one discharge channel for discharging the precursors from the surface of the substrate. The nozzle head comprises on output face to which the precursor nozzles and the discharge channels are provided. The nozzle head is arranged over a surface of the substrate to be coated and moved in reciprocating or similar manner over the surface in relation to the substrate. The relative movement of the substrate and the nozzle head may be carried out by moving the substrate or the nozzle head over alternatively moving both the substrate and the nozzle head in relation to each other. The precursors are supplied continuously and uninterruptedly from the precursor nozzles and also discharged to discharge channels. The relative movement and continuous supply of the precursors subjects the surface of the substrate alternatively and repeatedly to the first and second precursors and grows coating layers on the surface of the substrate.

The disadvantage of the prior art ALD coating methods and apparatuses is that forming coatings having different coating layers, meaning nanolaminate coatings, is difficult. The methods and apparatuses are designed to for only coating layers having one type of coating layer. Forming nanolaminates requires disrupting the coating process and adjusting the apparatus in order to form a different coating layer. When the coating is formed in a reaction chamber, the used starting materials have to be changed and the supply of the precursors have to be disrupted. If nanolaminates are produced with prior art nozzle heads without disrupting coating process, the nozzle head have to have extremely large number of precursor nozzles, as the nanolaminate structure is defined by the precursor nozzles of the nozzle head. This means that the nozzle head have to have suitable number of different precursor nozzles corresponding the desired nanolaminate structure. Furthermore, the conventional pulsing of the starting materials into the reaction chamber is slow as the whole reaction chamber has to be exhausted and purged between the different precursor pulses. However, when nozzle head is used, the precursors are supplied continuously from the precursor nozzles and nozzle head and the substrate are moved relative to each other. Therefore, when the coating comprises different coating layers, the supply of the precursors and the movement of the nozzle head have to be disrupted and the precursors changed so that the new coating layer may be formed using different precursors. Alternative, the different coating layers are formed in different reaction chambers or with different nozzle heads. This makes the process complicated and modifications of different coating layers in the coating difficult and complicated.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention disclosure is thus to provide a method and an apparatus for implementing the method so as to overcome or at least alleviate the above disadvantages.

The invention is based on the idea of providing a method for subjecting a surface of a substrate to successive surface reactions of at least a first precursor, a second precursor and a first subsequent precursor according to the principles of atomic layer deposition for forming on the surface of the substrate a coating comprising two or more different coating layers. The method is carried out with a nozzle head comprising one or more first precursor nozzles for forming a first precursor zone and one or more second precursor nozzles for forming a second precursor zone. The method comprises:a primary deposition step comprising subjecting the surface of the substrate to the first precursor in the first precursor zone and subjecting the surface of the substrate to the second precursor in the second precursor zone for forming a first coating layer on the surface of the substrate;a first changing step comprising changing the first precursor in the first precursor zone to a first subsequent precursor which is different than the first and second precursors;an alternate deposition step comprising subjecting the surface of the substrate to the first subsequent precursor in the first precursor zone and subjecting the surface of the substrate to the second precursor in the second precursor zone for forming a subsequent coating layer on the surface of the substrate; andtransporting the substrate and simultaneously moving the nozzle head in reciprocating manner over the surface of the substrate for carrying out the primary deposition step and the alternate deposition step.

In one embodiment the method may comprise transporting the substrate in constant velocity or transporting the substrate linearly in constant velocity. The substrate may also be transported past the nozzle head, or inside a reaction chamber or through a reaction chamber, the nozzle head being arranged inside the reaction chamber. In a specific embodiment the substrate may be transported from a first roll to a second roll or from a first roll to a second roll in a reaction chamber or through the reaction chamber, the nozzle head being arranged inside the reaction chamber.

The nozzle head may be moved in reciprocating manner between a first end position and second end position, or in reciprocating manner between a first end position and second end position in relation to the substrate (12). Alternative the nozzle head may be moved in reciprocating manner along a curved or loop path, or in reciprocating manner along a curved or loop path in relation to the substrate.

The primary deposition step comprising A) forming the first coating layer on the surface of the substrate, the first changing step comprising B) replacing the first precursor in the first precursor zone to the first subsequent precursor which is different than the first and second precursors, and the alternate deposition step comprising C) forming the subsequent coating layer on the surface of the substrate.

In one embodiment of the present invention the step A) of the primary deposition step for forming of the first coating layer comprises sub-step a) subjecting the surface of the substrate to the first precursor in the first precursor zone, sub-step b) subjecting the surface of the substrate to the second precursor in the second precursor zone after sub-step a), and sub-step c) performing sub-steps a) and b) one or more times successively until the first coating layer is formed on the surface of the substrate.

In one embodiment of the present invention the step B) of the first changing step comprises replacing the first precursor in the first precursor zone to the first subsequent precursor which is different than the first and second precursors.

In one embodiment of the present invention the step C) of the alternate deposition step for forming of the subsequent coating layer comprises sub-step d) subjecting the surface of the substrate to the first subsequent precursor in the first precursor zone, sub-step e) subjecting the surface of the substrate to the second precursor in the second precursor zone after step d), and sub-step f) performing sub-steps d) and e) one or more times successively until the subsequent coating layer is formed, the subsequent coating layer being different than the first coating layer.

In another embodiment the method further comprises a second changing step comprising step D) replacing the first subsequent precursor in the first precursor zone to the first precursor.

In one embodiment the method further comprises changing the second precursor in the second precursor zone to a second subsequent precursor which is different than the first precursor, the second precursors and the first subsequent precursor and subjecting the surface of the substrate to the first subsequent precursor in the first precursor zone and subjecting the surface of the substrate to the second subsequent precursor in the second precursor zone for forming the subsequent coating layer on the surface of the substrate.

The method may comprise steps A) forming the first coating layer on the surface of the substrate, B) replacing the first precursor in the first precursor zone to the first subsequent precursor which is different than the first and second precursors and replacing the second precursor in the second precursor zone to the second subsequent precursor which is different than the first precursor, the second precursors and the first subsequent precursor, and C) forming the subsequent coating layer on the surface of the substrate.

In one embodiment the method the step A) comprises sub-steps a) subjecting the surface of the substrate to the first precursor in the first precursor zone, b) subjecting the surface of the substrate to the second precursor in the second precursor zone after sub-step a), and c) performing sub-steps a) and b) one or more times successively until the first coating layer is formed on the surface of the substrate.

In one embodiment the step B) comprises replacing the first precursor in the first precursor zone to the first subsequent precursor which is different than the first and second precursors and replacing the second precursor in the second precursor zone to the second subsequent precursor which is different than the first precursor, second precursors and the first subsequent precursor.

In one embodiment the step C) comprises sub-steps d) subjecting the surface of the substrate to the first subsequent precursor in the first precursor zone, e) subjecting the surface of the substrate to the second subsequent precursor in the second precursor zone after sub-step d), and f) performing sub-steps d) and e) one or more times successively until the subsequent coating layer is formed, the subsequent coating layer being different than the first coating layer.

In another embodiment the method further comprises step D) replacing the first subsequent precursor in the first precursor zone to the first precursor and replacing the second subsequent precursor in the second precursor zone to the second precursor.

In one embodiment the method comprises repeating step A) after step D) for forming two first coating layers, or repeating steps A), B), C) and D) one or more times for forming two or more first coating layers and two or more subsequent coating layers.

In an alternative embodiment the method comprises repeating steps B) and C) one or more times using different first or second subsequent precursors in successive repeated steps B) and C) for forming two or more different subsequent coating layers, and repeating steps B) and C) after steps A) and D), or repeating steps B) and C) one or more times using different first or second subsequent precursors in successive repeated steps B) and C) for forming two or more different subsequent coating layers, and repeating steps B) and C) successively without repeating steps A) and D) between successive repeated steps B) and C).

According to one embodiment of the invention, the method may comprise using a third precursor as the first subsequent precursor in all of the repeated steps B) and C) for forming a subsequent coating layer in step C), or using two or more different first precursors as subsequent precursor in the repeated steps B) and C) for forming two or more different subsequent coating layers in repeated steps C).

According to another embodiment of the invention, the method may comprise using a third precursor as the first subsequent precursor in all of the repeated steps B) and C) and using a fourth precursor as the second subsequent precursor in all of the repeated steps B) and C) for forming the subsequent coating layer in step C), or using two or more different precursors as the first subsequent precursor in the repeated steps B) and C) and using two or more different precursors as the second subsequent precursor in the repeated steps B) and C) for forming two or more different subsequent coating layers in repeated steps C).

The present invention is also based on the idea of providing an apparatus for subjecting a surface of a substrate to successive surface reactions of at least a first precursor, a second precursor and a first subsequent precursor according to the principles of atomic layer deposition for forming on the surface of the substrate a coating comprising two or more different coating layers. The apparatus comprises:a nozzle head arranged to be over the surface of the substrate, the nozzle head having an output face comprising one or more first precursor nozzles and one or more second precursor nozzles;the one or more first precursor nozzles arranged to form one or more first precursor zones and arranged to subject the surface of the substrate to the first precursor;the one or more second precursor nozzles arranged to form one or more second precursor zones and arranged to subject the surface of the substrate to the second precursor;at least one first precursor source for the first precursor, the at least one first precursor source being connected to the one or more first precursor nozzles and arranged to supply the first precursor to the one or more first precursor zones;at least one second precursor source for the second precursor, the at least one second precursor source being connected to the one or more second precursor nozzles and arranged to supply the second precursor to the one or more second precursor zones;at least one first subsequent precursor source for the first subsequent precursor, the at least one first subsequent precursor source being connected to the one or more first precursor nozzles and arranged to supply the first subsequent precursor to the one or more first precursor zones;a transport mechanism arranged to transport the substrate; anda moving mechanism arranged to move the nozzle head in reciprocating manner over the surface of the substrate forming on the surface of the substrate a coating comprising two or more different coating layers.

In one embodiment the apparatus may further comprises at least one second subsequent precursor source for a second subsequent precursor, the at least one second subsequent precursor source being connected to the one or more second precursor nozzles and arranged to supply the second subsequent precursor to the one or more second precursor zones.

In one embodiment of the present invention the at least one first precursor source comprises a first precursor container for receiving the first precursor and a first precursor conduit arranged between the first precursor container and the one or more first precursor nozzles for supplying the first precursor from the first precursor container to the one or more first precursor zones, and the at least one second precursor source comprises a second precursor container for receiving the second precursor and a second precursor conduit arranged between the second precursor container and the one or more second precursor nozzles for supplying the second precursor from the second precursor container to the one or more second precursor zones. The at least one first subsequent precursor source further comprises a first subsequent precursor container for receiving the first subsequent precursor and a first subsequent precursor conduit arranged between the first subsequent precursor container and the one or more first precursor nozzles for supplying the first subsequent precursor from the first subsequent precursor container to the one or more first precursor zones.

In one embodiment the at least one second subsequent precursor source comprises a second subsequent precursor container for receiving the second subsequent precursor and a second subsequent precursor conduit arranged between the second subsequent precursor container and the one or more second precursor nozzles for supplying the second subsequent precursor from the second subsequent precursor container to the one or more second precursor zones.

In one embodiment of the present invention the first precursor zone comprises one or more first precursor nozzles for supplying the first precursor and the first subsequent precursor, the one or more first precursor nozzles being connected to the first precursor container via the first precursor conduit and to the first subsequent precursor container via the first subsequent precursor conduit. The second precursor zone comprises one or more second precursor nozzles or one for supplying the second precursor, the one or more second precursor nozzles being connected to the second precursor container via the second precursor conduit.

In an alternative embodiment the first precursor zone comprises one or more first precursor nozzles for supplying the first precursor and the first subsequent precursor, the one or more first precursor nozzles or the one being connected to the first precursor container via the first precursor conduit and to the first subsequent precursor container via the first subsequent precursor conduit. The second precursor zone comprises one or more second precursor nozzles for supplying the second precursor and the second subsequent precursor, the one or more second precursor nozzles being connected to the second precursor container via the second precursor conduit and to the second subsequent precursor container via the second subsequent precursor conduit.

An advantage of the method and apparatus of the present invention is that different coating layers may be formed on the surface of the substrate during the same coating process without disrupting the coating process with a nozzle head in a spatial atomic layer deposition process. Furthermore, the present invention is enables forming complex nanolaminates or coating structures in efficient manner by changing the first precursor during the coating process. This further enables creating new kind of coating having functional structures provided with different coating layers.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description same reference numerals denote same or corresponding features, parts or method steps in different embodiment of the present invention. For simplicity the description of these same or corresponding features, parts or method steps is not repeated in reference to every embodiment of the present invention.

In the context of this application the term “coating” means the overall coating formed on a substrate and the coating may comprise one or more coating layers. The term “coating layer” means a layer of one coating material provided on the surface of the substrate and the coating layer comprises one or more atomic layers of coating material. One atomic layer is produced by one atomic layer deposition cycle in which the surface of the substrate is subjected once to at least two different precursors.

FIG. 1shows schematically a conventional prior art apparatus1for carrying out atomic layer deposition. The apparatus1comprises a vacuum chamber2defining a vacuum space4. The apparatus may also comprise a vacuum pump (not shown) for providing vacuum or low-pressure inside the vacuum chamber2. The apparatus1further comprises a reaction chamber6defining a reaction space8. The reaction space8is preferably sealed or separated from the vacuum space8. In some embodiments the reaction chamber6may be omitted and the vacuum chamber2forms also the reaction chamber. The reaction chamber6is provided with an inlet opening3for loading or feeding a substrate12into the reaction chamber6and with an outlet opening5for unloading or removing a substrate12from the reaction chamber6. The inlet and outlet openings3,5may be provided with gas barriers or port valves or the like for sealing the inlet and outlet openings3,5such that gaseous precursor do not flow out of the reaction chamber6. It should be noted that outlet opening5may be omitted and the substrate may be fed into the reaction chamber6and removed from the reaction chamber6via the same inlet opening3.

In the apparatus1ofFIG. 1the substrate is a web like substrate12which is transported with a transport mechanism through the reaction chamber6. The transport mechanism comprises a first roll14and a second roll16, and the substrate12is transported from the first roll14to the second roll16in the direction X, as shown inFIG. 1. In this embodiment the first roll14and the second roll16are arranged outside the reaction chamber6but inside the vacuum chamber2for transporting the substrate12through the reaction chamber6. However, in an alternative embodiment the first and second roll14,16may be arranged inside the reaction chamber for transporting the substrate12from the first roll14to the second roll16inside the reaction chamber6or the first and second roll14,16may be arranged even outside the vacuum chamber2. It should be noted that the substrate12may also be separate piece which is loaded separate into the reaction chamber6or transported through the reaction chamber6. It should be noted that the substrate12may be transported also from the second roll16to the first roll14, and possibly two or more times between the first and second rolls14,16. In this embodiment the substrate12may be a flexible substrate12which may be provided to the first and second roll14,16.

Inside the reaction chamber6is provided a nozzle head10having output face11. First and second precursors are supplied via the output face11of the nozzle head10to the surface of the substrate12for subjecting the surface of the substrate successively to the first and second precursors according to the principles of atomic layer deposition. The nozzle head10may be moved inside the reaction space6in relation to the substrate12. In one embodiment the nozzle head is moved with a moving mechanism60in reciprocating manner between two end position over the surface of the substrate in direction of arrow Z as shown inFIG. 1, or in some other reciprocating manner. Preferably the nozzle head10is moved in reciprocating manner parallel or in the direction of the surface of the substrate12. Therefore, the distance between the output face11of the nozzle head10and the surface of the substrate12may be maintained constant during the reciprocating movement of the nozzle head12. In one embodiment of the invention the moving mechanism60is arranged to move the nozzle head10is in reciprocating manner and linearly in a plane. In another embodiment the moving mechanism60is arranged to move the nozzle head10is in reciprocating manner in a pendulum movement between a first end position and the second end position. In the latter embodiment the substrate12may be transported on a transport cylinder and the nozzle head10is moved at a constant distance over the transport cylinder and the substrate10.

FIG. 2shows an alternative embodiment in which the substrate12is a separate piece, preferably a planar separated piece. In this embodiment the apparatus does not comprise any reaction chamber surrounding the nozzle head10. Thus, the nozzle head10may be arranged to discharge precursor gases such that there is no need for the reaction chamber. The substrate12may be transported with a transport mechanism70past the nozzle head10such that output face11of the nozzle head such that the surface of the substrate12may be subjected to the precursors. In this embodiment the transport mechanism70comprises transport rolls on which the substrate12is transported in the direction of arrows Y in one direction or in both directions. The nozzle head10may be moved in similar manner with the moving mechanism60as in the embodiment ofFIG. 1over the surface of the substrate12. In this embodiment the substrate12may be a rigid substrate12.

It should be noted that the apparatus ofFIG. 1may be provided without the reaction chamber6and/or the vacuum chamber2, and the embodiment ofFIG. 2may be provided with the reaction chamber6and/or the vacuum chamber2.

It should also be noted that the transport mechanism14,16,70may be any conventional transport mechanism capable of transporting the substrate12past the nozzle head10, inside the reaction chamber6or through the reaction chamber.

The transport mechanism14,16,70of the present invention may be arranged to transport the substrate12in constant velocity or linearly in constant velocity, for example in the direction X as inFIG. 1, in relation to the apparatus. The moving mechanism60of the nozzle head10may be arranged to move the nozzle head10in reciprocating manner between a first end position and second end position or between a first end position and second end position in relation to the substrate12. In an alternative embodiment the moving mechanism60is arranged to move the nozzle head10in reciprocating manner along a curved path or loop path, or along a curved or loop path in relation to the substrate12.

FIG. 3shows one embodiment of the present invention and particularly one embodiment of the nozzle head10. The output face11of the nozzle head10is provided with one or more first precursor nozzles30for supplying a first precursor A via the output face11and with one or more second precursor nozzles40for supplying a second precursor B via the output face11. The output face11further comprises discharge channels20provided on both sides of the first and second precursor nozzles30,40such that each first and second precursor nozzle30,40is provided between two discharge channels20.

The discharge channels20are connected via discharge line22to discharge pumps26, or to a common discharge pump26, for providing suction to the output face11for discharging precursors from the output face11. The discharge line22may be provided with a discharge valve24for opening and closing the discharge line22.

The one or more second precursor nozzles40are connected to a second precursor container46via a second precursor conduit42for supplying the second precursor B via the output face11. The second precursor conduit42may be provided with a second precursor conduit valve44for opening and closing the second precursor line42for supplying and interrupting the supply of the second precursor B.

The one or more first precursor nozzles30are connected to a first precursor container32via a first precursor conduit34for supplying the first precursor A via the output face11and to a first subsequent precursor container33via the first subsequent precursor conduit36supplying a first subsequent precursor C via the output face11. The first precursor conduit34may be provided with a first precursor conduit valve35and the subsequent precursor conduit36may be provided with a first subsequent precursor conduit valve37for opening and closing the first precursor conduit34and the first subsequent precursor conduit37, respectively, for supplying and interrupting the supply of the first precursor A and the first subsequent precursor C. The apparatus further comprises a first zone supply conduit38connected to both the first precursor conduit34and the first subsequent precursor conduit36and to the one or more first precursor nozzle30for supplying the first precursor A and the first subsequent precursor C via the common first zone supply conduit38to the first precursor nozzle30. The first zone supply conduit38may also be provided with a first zone supply conduit valve39for opening and closing the first zone supply conduit38and the supply of the first precursor A and the first subsequent precursor C.

The first precursor nozzle30is provided between the discharge channels20on the output face11. When the first precursor A or the first subsequent precursor C are supplied from the first precursor nozzle30they flow from the first precursor nozzle30via the output face11to the discharge channels20and thus the surface of the substrate12is subjected to the first precursor A or the first subsequent precursor C between the discharge channels. A first precursor zone100is therefore formed between the discharge channels20, as shown inFIG. 3. Similarly, the second precursor nozzle40is provided between the discharge channels20on the output face11. When the second precursor B is supplied from the second precursor nozzle40it flows from the second precursor nozzle40via the output face11to the discharge channels20and thus the surface of the substrate12is subjected to the second precursor B between the discharge channels. A first precursor zone200is therefore formed between the discharge channels20, as shown inFIG. 3.

In the embodiment ofFIG. 3, the output face11comprises in the following order: a discharge channel20, a first precursor nozzle30, a discharge channel20and a second precursor nozzle40. Furthermore, the output face11comprises in the flowing order: a first precursor zone100and a second precursor zone200. These mentioned orders may be repeated one or more times. Thus when the nozzle head10and the substrate12are moved in relation to each other the surface of the substrate12is successively and alternatingly subjected to the first precursor zone100and the second precursor zone200.

As shown inFIG. 3, the first precursor container32is connected to the first precursor nozzle30and to the first precursor zone100via the first precursor conduit34and the first zone supply conduit38and the first subsequent precursor container33is also connected to the first precursor nozzle30and to the first precursor zone100via the first subsequent precursor conduit36and the first zone supply conduit38. Thus both the first precursor source32and the first subsequent precursor source33are both connected to the first precursor nozzle30and the first precursor zone100such that both the first precursor A and the first subsequent precursor B may be supplied via the first precursor nozzle30and the first precursor zone100. This enables changing the first precursor A to the first subsequent precursor C during the coating process such that different coating layers may be formed on the surface of the substrate12. Accordingly, a first coating layer may be formed using first and second precursors A, B and a subsequent coating layer using subsequent precursor C and precursor B.

It should be noted that the apparatus may comprise one or more different first subsequent precursor containers or sources connected to the first precursor nozzle30and to the first precursor zone100in similar manner as the first subsequent precursor container33or the first subsequent precursor source ofFIG. 3. Each of these different first subsequent precursor containers or precursor sources may comprise different first subsequent precursors.

FIG. 4shows an alternative embodiment of the nozzle head10according to the present invention, the nozzle head ofFIG. 4being a modification of the nozzle head10ofFIG. 3. The embodiment ofFIG. 4comprises purge gas nozzles50provided to the output face11of the nozzle head10. One purge gas nozzle50may be provided between the first and second precursor nozzles30,40or between the first and second precursor zone100,200for separating the first and second precursor zone100,200from each other. Purge gas nozzles50may also be provided between end of the output face11and the first or second precursor zone100,200.

In the embodiment ofFIG. 4, the output face11comprises in the following order: a discharge channel20, a purge gas channel50, a discharge channel20, a first precursor nozzle30, a discharge channel20, a purge gas channel50, a discharge channel50and a second precursor nozzle40. Furthermore, the output face11comprises in the flowing order: a discharge channel20, a purge gas channel50, a discharge channel20, a first precursor zone100, a discharge channel20, a purge gas channel50, a discharge channel50and a second precursor zone200. These mentioned orders may be repeated one or more times.

The apparatus may further comprise a purge gas container56which is connected to the purge gas nozzle50via a purge gas line52for supplying purge gas P via the output face11. The purge gas line52may also be provided with a purge gas valve54for opening and closing the purge gas line52and the supply of the purge gas P.

FIG. 5shows an alternative embodiment of the nozzle head10according to the present invention, the nozzle head ofFIG. 5being a modification of the nozzle head10ofFIG. 3. In this embodiment there is no first zone supply conduit38. In this embodiment the first precursor conduit34and the first subsequent precursor conduit36are connected to the first zone precursor nozzle30as separate conduits. This means that the first precursor conduit34extends directly between the first precursor container32and the first precursor nozzle30, and the first subsequent precursor conduit36extends directly between the first subsequent precursor container33and the first precursor nozzle30. Other features and structures of the embodiment ofFIG. 5correspond the features and structures ofFIG. 3.

FIG. 6shows an alternative embodiment of the nozzle head10according to the present invention, the nozzle head ofFIG. 6being a modification of the nozzle head10ofFIG. 3. In the embodiment ofFIG. 6the output face11comprises one or more first precursor nozzles98for supplying the first precursor A and one or more first subsequent precursor nozzles99for supplying the first subsequent precursor C via the output face11. Accordingly, the first precursor zone100is provided with separate nozzles98,99for the first precursor A and the first subsequent precursor C. Therefore, the first precursor nozzle98is connected directly to the first precursor container32via the first precursor conduit34and the first subsequent precursor nozzle99is connected directly to the first subsequent precursor container33via the subsequent precursor conduit36. Therefore, the first precursor A and the first subsequent precursor C may be supplied separately from each other to the first precursor zone100. Other features and structures of the embodiment ofFIG. 6correspond the features and structures ofFIG. 3.

In the following is described an alternative type of apparatus1for implementing the present invention. The apparatus described in connection withFIGS. 6 to 10does not disclose a nozzle head10, but main features of the invention are same in the apparatuses ofFIGS. 3 to 6.

FIG. 7shows an alternative embodiment of the nozzle head10according to the present invention, the nozzle head ofFIG. 6being a modification of the nozzle head10ofFIGS. 3 and 5. In this embodiment also the second precursor B may be replaced with a second subsequent precursor D. Therefore, the apparatus ofFIG. 6comprises at least one second subsequent precursor source45for a second subsequent precursor D. The at least one second subsequent precursor source45is connected to the one or more second precursor zones200and arranged to supply the second subsequent precursor D to the one or more second precursor zones200. The at least one second subsequent precursor source comprises a second subsequent precursor container45for receiving the second subsequent precursor D and a second subsequent precursor conduit41arranged between the second subsequent precursor container45and the one or more second precursor zones200for supplying the second subsequent precursor D from the second subsequent precursor container45to the one or more second precursor zones200. The second precursor zone200comprises one or more second zone precursor nozzles40for supplying the second precursor B and the second subsequent precursor D, the one or more second zone precursor nozzles40being connected to the second precursor container46via the second precursor conduit42and to the second subsequent precursor container45via the second subsequent precursor conduit41.

In the embodiment ofFIG. 7, the second precursor conduit42and the second subsequent precursor conduit41are connected to the one or more second zone precursor nozzles40as separate conduits.

In an alternative embodiment, as inFIG. 3, the apparatus may further comprise a second zone supply conduit connected to both the second precursor conduit42and the second subsequent precursor conduit41and to the one or more second zone precursor nozzles40for supplying the second precursor B and the second subsequent precursor D via the common second zone supply conduit.

In a yet alternative embodiment the second precursor zone200may comprise one or more second precursor nozzles for supplying the second precursor B and one or more second subsequent precursor nozzles for supplying the second subsequent precursor D. The one or more second precursor nozzles are connected to the second precursor container46via the second precursor conduit42and the one or more second subsequent precursor nozzles being connected to the second subsequent precursor container45via the second subsequent precursor conduit41.

According to the above mentioned, the supply of the second subsequent precursor may be provided in the same manner as the first subsequent precursor.

According to the above description in relation to different embodiments, the present invention provides an apparatus comprising:one or more first precursor zones100arranged to subjected the surface of the substrate12to the first precursor A and one or more second precursor zones200arranged to subject the surface of the substrate12to the second precursor B;at least one first precursor source32,34for the first precursor A, the at least one first precursor source32,34is connected to the one or more first precursor zones100and arranged to supply the first precursor A to the one or more first precursor zones100and at least one second precursor source42,46for the second precursor B, the at least one second precursor source42,46being connected to the one or more second precursor zones200and arranged to supplying the second precursor B to the one or more second precursor zones200.

According to the present invention the apparatus further comprises at least one first subsequent precursor source33,36for the first subsequent precursor C, the at least one first subsequent precursor source33,36being connected to the one or more first precursor zones100and arranged to supply the first subsequent precursor C to the one or more first precursor zones100. Therefore, the apparatus of the present invention enables changing the precursor in the first precursor zone100during the coating process. It should be noted that the apparatus may comprise several first coating zones100, and the changing of the precursor in the first precursor zone100may be carried out separately in individual first precursor zones100, in groups of first precursor zones100or in all the first precursor zones100at the same time.

The apparatus may further comprise at least one second subsequent precursor source45,41for the second subsequent precursor D, the at least one second subsequent precursor source45,41is connected to the one or more second precursor zones200and arranged to supply the second subsequent precursor D to the one or more second precursor zones200. Therefore, the apparatus of the present invention enables changing the precursor in the second precursor zone200during the coating process. It should be noted that the apparatus may comprise several second coating zones200, and the changing of the precursor in the second precursor zone200may be carried out separately in individual second precursor zones200, in groups of second precursor zones200or in all the second precursor zones200at the same time.

The present invention provides further a method for subjecting a surface of a substrate12to successive surface reactions of at least a first precursor A, a second precursor B and a subsequent precursor C according to the principles of atomic layer deposition for forming on the surface of the substrate12a coating comprising two or more different coating layers. The method may be implemented with an apparatus as described above.

The method comprises:

a primary deposition step comprising subjecting the surface of the substrate12to the first precursor A in a first precursor zone100and subjecting the surface of the substrate12to the second precursor B in a second precursor zone200for forming a first coating layer302on the surface of the substrate12,

a first changing step comprising changing the first precursor A in the first precursor zone100to a subsequent precursor C which is different than the first and second precursors A, B,

an alternate deposition step comprising subjecting the surface of the substrate12to the subsequent precursor C in the first precursor zone100and subjecting the surface of the substrate12to the second precursor B in the second precursor zone200for forming a subsequent coating layer on the surface of the substrate12, andtransporting the substrate12and simultaneously moving the nozzle head10in reciprocating manner over the surface of the substrate12for carrying out the primary deposition step and the alternate deposition step.

According to the above mentioned the primary deposition step comprises steps:

A) forming the first coating layer on the surface of the substrate12, the forming of the first coating layer comprising sub-steps:a) subjecting the surface of the substrate12to the first precursor A in the first precursor zone100;b) subjecting the surface of the substrate12to the second precursor B in the second precursor zone200after sub-step a); andc) performing sub-steps a) and b) one or more times successively until the first coating layer is formed on the surface of the substrate12.

The first changing step further comprises:

B) replacing the first precursor A in the first precursor zone100to the subsequent precursor C which is different than the first and second precursors A, B, and

the alternate deposition step comprises:

C) forming the subsequent coating layer on the surface of the substrate12, the forming of the subsequent coating layer comprising sub-steps:d) subjecting the surface of the substrate12to the subsequent precursor (C) in the first precursor zone100;e) subjecting the surface of the substrate12to the second precursor B in the second precursor zone200after sub-step d); andf) performing sub-steps d) and e) one or more times successively until the subsequent coating layer is formed, the subsequent coating layer being different than the first coating layer.

The method may further comprises a second changing step comprising step D) replacing the subsequent precursor C in the first precursor zone100to the first precursor A.

The method may further comprise changing the second precursor B in the second precursor zone200to a second subsequent precursor D which is different than the first precursor A, the second precursor B and the first subsequent precursor C, and subjecting the surface of the substrate12to the first subsequent precursor C in the first precursor zone100and subjecting the surface of the substrate12to the second subsequent precursor D in the second precursor zone200for forming a subsequent coating layer on the surface of the substrate12. Thus the first and second precursors A, B may both be replaced with the first and second subsequent precursors C, D, respectively, at the same time or at different times separately.

Accordingly, the method may comprise steps:

A) forming the first coating layer on the surface of the substrate12, the forming of the first coating layer comprising sub-steps:a) subjecting the surface of the substrate12to the first precursor A in the first precursor zone100;b) subjecting the surface of the substrate12to the second precursor B in the second precursor zone200after sub-step a); andc) performing sub-steps a) and b) one or more times successively until the first coating layer is formed on the surface of the substrate12,

The method further comprises:

B) replacing the first precursor A in the first precursor zone100to the first subsequent precursor C which is different than the first and second precursors A, B and replacing the second precursor B in the second precursor zone200to the second subsequent precursor D which is different than the first precursor, second precursors and the first subsequent precursor A, B, C; and

C) forming the subsequent coating layer on the surface of the substrate12, the forming of the subsequent coating layer comprising sub-steps:d) subjecting the surface of the substrate12to the first subsequent precursor C in the first precursor zone100;e) subjecting the surface of the substrate12to the second subsequent precursor D in the second precursor zone200after sub-step d); andf) performing sub-steps d) and e) one or more times successively until the subsequent coating layer is formed, the subsequent coating layer being different than the first coating layer.

The method may further comprise step D) replacing the first subsequent precursor C in the first precursor zone100to the first precursor A and replacing the second subsequent precursor D in the second precursor zone200to the second precursor B.

When the coating is provided on the surface of the substrate the method may comprise repeating step A) after step D) for forming two first coating layers and only subsequent coating layer, or it may comprise repeating steps A), B), C) and D) one or more times for forming two or more first coating layers and two or more subsequent coating layers.

In an alternative embodiment the method may comprise repeating steps B) and C) one or more times using different first and/or second subsequent precursors in successive repeated steps B) and C) for forming two or more different subsequent coating layers, and repeating steps B) and C) after steps A) and D). In a yet alternative embodiment the method may comprise repeating steps B) and C) one or more times using different first and/or second subsequent precursors in successive repeated steps B) and C) for forming two or more different subsequent coating layers, and repeating steps B) and C) successively without repeating steps A) and D) between successive repeated steps B) and C). According to the above mentioned a predetermined third precursor C may be used as the first subsequent precursor in all of the repeated steps B) and C) for forming a subsequent coating layer in step C) and in all the repeated step C). Alternative two or more different precursors may be used as the first subsequent precursor in the repeated steps B) and C) for forming two or more different subsequent coating layers in repeated steps C).

In a yet alternative embodiment a predetermined third precursor C may be used as the first subsequent precursor in all of the repeated steps B) and C) and a predetermined fourth precursor D may be used as the second subsequent precursor in all of the repeated steps B) and C) for forming a subsequent coating layer (304) in step C). In alternative embodiment two or more different precursors may be used as the first subsequent precursor C in the repeated steps B) and C) and/or two or more different precursors may be used as the second subsequent precursor D in the repeated steps B) and C) for forming two or more different subsequent coating layers in repeated steps C).

FIG. 8Ashows a coating of a substrate12provided according to the present invention. The first coating layer302is provided in steps A) first with the first and second precursors A, B. Then a subsequent coating layer304is formed according to steps B) and C) with first subsequent precursor C and the second precursor B, or with first subsequent precursor C and second subsequent precursor D. After forming the subsequent coating layer304the step D) is carried out and step A) repeated. Then steps B), C), D) and A) are all repeated still once for forming three first coating layers302and two subsequent coating layers304.

FIG. 8Bshows an alternative embodiment in which the first coating layer302is provided in steps A) first with the first and second precursors A, B. Then a subsequent coating layer304is formed according to steps B) and C) with a first subsequent precursor and the second precursor B. After that a subsequent coating layer306is formed according to steps B) and C) with the first subsequent precursor C and the second subsequent precursor. Then the subsequent coating layer304is provided again with the first subsequent precursor C and the second precursor B in repeated steps B) and C). And finally, the step D) is carried out and step A) repeated for providing the first coating layer302again.

As can be seen, the subsequent coating layer306has different thickness than the other coating layers302,304. The thickness of the coating layer depends how many times the steps a), b) and e) and f) are repeated in steps A) and C), respectively.

In the method the step A) may be carried out by supplying the first precursor A to the first coating zone100for subjecting the surface of the substrate12to the first precursor A in the first precursor zone100and by supplying the second precursor B to the second precursor zone200for subjecting the surface of the substrate12to the second precursor B in the second precursor zone86,200. The step C) may be carried out by supplying the first subsequent precursor C to the first coating zone100for subjecting the surface of the substrate12to the first subsequent precursor C in the first precursor zone100and by supplying the second precursor B to the second precursor zone200for subjecting the surface of the substrate12to the second precursor B in the second precursor zone200.

In the present invention it should be noted that always the first precursor A and the second precursor B are supplied continuously to the first precursor zone100and the second precursor zone200, respectively, in step A), and the first subsequent precursor C and the second precursor B or the second subsequent precursor D are supplied continuously to the first precursor zone100and the second precursor zone200, respectively, in step C). Therefore, the present invention does not comprise pulsing the precursors as in the conventional ALD-process in a reaction chamber. In the present invention the precursors are fed continuously in each step and sub-step until the first precursor A is replaced by the first subsequent precursor C and/or the second precursor B with the second subsequent precursor D, or vice versa.

In one embodiment the first precursor A is trimethylaluminium Al2(Ch3)6(TMA) and the second precursor is water H2O. Thus, the formed first coating layer is aluminium oxide layer Al2O3. In this embodiment the first subsequent precursor C is titanium tetrachloride TiCl4. The formed subsequent coating layer is titanium dioxide layer TiO2. Therefore, in this embodiment the metal precursor is changed and replaced, meaning that only the first precursor is changed to the first subsequent precursor.

In an alternative embodiment the first precursor A is trimethylaluminium Al2(Ch3)6(TMA) and the second precursor is water H2O. Thus, the formed first coating layer is aluminium oxide layer Al2O3. In this embodiment the first subsequent precursor C is diethyl zinc (C2H5)2Zn (DEZ). The formed subsequent coating layer is zinc oxide layer ZnO. Therefore, also in this embodiment the metal precursor is changed and replaced, meaning that only the first precursor is changed to the first subsequent precursor.

In a yet alternative embodiment the first precursor A is dihydrogen monosulfide H2S and the second precursor B is diethyl zinc (C2H5)2Zn (DEZ). Thus, the formed first coating layer is zinc sulphide layer ZnS. In this embodiment the first subsequent precursor C is water H2O. Thus, formed the subsequent coating layer zinc oxide layer ZnO. Therefore, in this embodiment the non-metal precursor is changed and replaced, meaning that only the first precursor is changed to the first subsequent precursor.

In another embodiment both the first precursor A and the second precursor B are replaced. In this embodiment the first precursor A is trimethylaluminium Al2(Ch3)6(TMA) and the second precursor is water H2O. The formed first coating layer is aluminium oxide layer Al2O3. The first subsequent precursor C is diethyl zinc (C2H5)2Zn (DEZ) and the second subsequent precursor D is dihydrogen monosulfide H2S. Therefore, the formed subsequent coating layer is zinc sulphide layer ZnS. Accordingly, in this embodiment both the first and second precursors A, B are replaced and thus the metal precursor and the non-metal precursor are replaced and changed.

It should be noted, that according to the present invention one of the first and second precursors may be replaced or alternative both the first and second precursors may be replaced. The replaced precursor may be the metal precursor or the non-metal precursor or the metal precursor and the non-metal precursor.