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Title:
NOZZLE HEAD
Document Type and Number:
WIPO Patent Application WO/2012/028782
Kind Code:
A1
Abstract:
The present invention relates to a nozzle head (2) for subjecting a surface (4) of a substrate (6) to successive surface reactions of at least a first precursor (A) and a second precursor (B). The nozzle head (2) comprising two or more elongated precursor nozzles (8, 10) for subjecting the surface (4) of the substrate (6) to the first and second precursors (A, B). According to the present invention the nozzle head (2) comprises on the output face (5) precursors nozzles (8, 10), purge gas channels (12) and the discharge channels (42, 46) in succession in the following order: at least a first precursor nozzle (8), a first discharge channel (42), purge gas channel (12), a second precursor nozzle (10), a second discharge channel (46) and a purge gas channel (12), optionally repeated a plurality of times.

Inventors:
SOININEN PEKKA (FI)
ENHOLM ROBIN (FI)
Application Number:
PCT/FI2011/050750
Publication Date:
March 08, 2012
Filing Date:
August 29, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BENEQ OY (FI)
SOININEN PEKKA (FI)
ENHOLM ROBIN (FI)
International Classes:
C23C16/455
Domestic Patent References:
WO2008130369A12008-10-30
WO2011041255A12011-04-07
Foreign References:
US20080166884A12008-07-10
US20100310771A12010-12-09
Attorney, Agent or Firm:
KOLSTER OY AB (P.O. Box 148, Helsinki, FI)
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Claims:
Claims

1 . A nozzle head (2) for subjecting a surface (4) of a substrate (6) to successive surface reactions of at least a first precursor (A) and a second pre- cursor (B), the nozzle head (2) having an output face (5) comprising:

- one or more first supply channels (40) for subjecting the surface (4) of the substrate (6) to the first precursor (A);

- one or more second supply channels (44) for subjecting the surface (4) of the substrate (6) to the second precursor (B);

- one or more purge gas channels (12) for subjecting the surface (4) of the substrate (6) to a purge gas; and

- one or more discharge channels (42, 46) for discharging first and second precursor (A, B) and purge gas,

characterized in that the supply channels (40, 44), purge gas channels (12) and the discharge channels (42, 46) are longitudinal and arranged in succession in the following order: a purge gas channel (12), a first supply channel (40), a discharge channel (42), a purge gas channel (12), a second supply channel (44) and a discharge channel (46), optionally repeated a plurality of times.

2. A nozzle head (2) according to claim 1 , characterized in that the supply channels (40, 44), purge gas channel (12) and the discharge channels (42, 46) are arranged to extend substantially parallel.

3. A nozzle head (2) according to claim 1 or 2, characterized in that that the output face (5) is a plane.

4. A nozzle head (2) according to any one of claims 1 to 3, characterized in that the supply channels (40, 44) and the discharge channels (42, 46) are provided with a supply opening (47, 48, 43, 45) extending the longitudinal direction of the supply channel (40, 44) and the discharge channel (42, 46) and being open to the output face (5).

5. A nozzle head (2) according to any one of claims 1 to 4, characterized in that the nozzle head (2) comprises at least one first precursor nozzle (8) provided with a first supply channel (40) and at least one second precursor nozzle (10) provided with a second supply channel (44).

6. A nozzle head (2) according to any one of claims 1 to 5, charac- terized in that the nozzle head (2) comprises two or more discharge nozzles provided with a discharge channel (42, 46).

7. A nozzle head (2) according to claim 5, characterized in that the discharge channel (42, 46) is provided to the precursor nozzle (8, 10) and extending substantially parallel to the supply channel (40, 44).

8. A nozzle head (2) according to any one of claims 1 to 7, charac- terized in that the purge gas channels (12) are arranged in passive fluid connection to a purge gas source (14, 16) for subjecting the surface (4) of the substrate (6) to a purge gas.

9. A nozzle head (2) according to claim 8, characterized in that the purge gas source is the gas atmosphere (14) surrounding the nozzle head (2) or a separate purge gas container (16).

10. A nozzle head (2) according to claim 8 or 9, characterized in that the one or more first precursor nozzles (8) are arranged to operate at a first pressure at the output face (5), and that the one or more second precursor nozzles (10) are arranged to operate at a second pressure at the output face (5), and that the purge gas source (14, 16) is arranged to a third pressure higher than the first and second pressure.

1 1 . A nozzle head (2) according to any one of claims 8 to 10, characterized in that the nozzle head (2) comprises at least one first precursor nozzle (8) and at least one second precursor nozzle (10) arranged alternately successively and separated with gap, slit or opening forming the purge gas channel (12).

12. A nozzle head (2) according to claim 1 1 , characterized in that the nozzle head (2) is a grate-like structure in which the first and second precursor nozzles (8, 10) form the rods and the purge gas channels (12) form the gaps between the rods.

13. A nozzle head (2) according to any one of claims 1 to 9, characterized in that the supply channel (40, 44) is arranged to supply precursor (A, B) substantially along the whole length of the supply channel (40, 44) and the discharge channel (42, 46) is arranged to discharge precursor (A, B) substan- tially along the whole length of the discharge channel (42, 46).

14. A nozzle head (2) according to any one of claims 4 to 13, characterized in that the supply channel (40, 44) is arranged to supply precursor (A, B) substantially along the whole length of the supply opening (47, 48) and the discharge channel (42, 46) is arranged to discharge precursor (A, B) sub- stantially along the whole length of the discharge opening (43, 45).

15. A nozzle head (2) according to any one of claims 1 to 14, characterized in that the precursor nozzle (8, 10) or the supply channel (40, 44) is arranged to supply precursor (A, B) substantially perpendicularly to the output face (5).

16. A nozzle head (2) according to any one of claims 1 to 15, characterized in that the precursor nozzle (8, 10) or the discharge channel (42, 46) is arranged to discharge precursor (A, B) substantially perpendicularly to the output face (5).

17. A nozzle head (2) according to any one of claims 5 to 16, char- acterized in that the precursor nozzle (8, 10) comprises a reaction space (50) provided between the supply channel (40, 44) and the discharge channel (42, 46), the reaction space (50) being open to the output face (5) for subjecting the surface (4) of the substrate (6) to precursor (A, B).

18. A nozzle head (2) according to claim 17, characterized in that the reaction space (50) is arranged to between the output face (5) and the supply and discharge channels (40, 44, 42, 46).

19. A nozzle head (2) according to claim 17 or 18, characterized in that the precursor (A, B) is arranged to flow from the supply channel (40, 44) through the reaction space (50) to the discharge channel (42, 46).

20. An apparatus for processing a surface (4) of a substrate (6), the apparatus comprising:

- a process chamber (26) having inside a gas atmosphere (14);

- a nozzle head (2) arranged inside the process chamber (26) for subjecting the surface (4) of the substrate (6) to successive surface reactions of at least a first precursor (A) and a second precursor (B),

the nozzle head (2) having an output face (5) comprising:

- one or more first supply channels (40) for subjecting the surface (4) of the substrate (6) to the first precursor (A);

- one or more second supply channels (44) for subjecting the sur- face (4) of the substrate (6) to the second precursor (B);

- one or more purge gas channels (12) for subjecting the surface (4) of the substrate (6) to a purge gas; and

- one or more discharge channels (42, 46) for discharging first and second precursor (A, B) and purge gas,

characterized in that the supply channels (40, 44), purge gas channels (12) and the discharge channels (42, 46) are longitudinal and ar- ranged in succession in the following order: a purge gas channel (12), a first supply channel (40), a discharge channel (42), a purge gas channel (12), a second supply channel (44) and a discharge channel (46), optionally repeated a plurality of times.

21. An apparatus according to claim 20, characterized in that the supply channels (40, 44), purge gas channel (12) and the discharge channels (42, 46) are arranged to extend substantially parallel.

22. An apparatus according to claim 20 or 21 , characterized in that the supply channels (40, 44) and the discharge channels (42, 46) are provided with a supply opening (47, 48, 43, 45) extending the longitudinal direction of the supply channel (40, 44) and the discharge channel (42, 46) and being open to the output face (5).

23. An apparatus according to any one of claims 20 to 22, characterized in that the nozzle head (2) comprises at least one first precursor nozzle (8) provided with a first supply channel (40) and at least one second precursor nozzle (10) provided with a second supply channel (44).

24. An apparatus according to claim 23, characterized in that the discharge channel (42, 46) is provided to the precursor nozzle (8, 10) and extending substantially parallel to the supply channel (40, 44).

25. An apparatus according to any one of claims 20 to 24, characterized in that the purge gas channels (12) are arranged in passive fluid connection to a purge gas atmosphere (14) inside the process chamber (26) for subjecting the surface (4) of the substrate (6) to the purge gas.

26. An apparatus according to claim 25, characterized in that the one or more first precursor nozzles (8) are arranged to operate at a first pressure at the output face (5), and that the one or more second precursor nozzles ( 0) are arranged to operate at a second pressure at the output face (5), and that the purge gas source (14, 16) is arranged to a third pressure higher than the first and second pressure.

27. An apparatus according to claim 25 or 26, characterized in that the nozzle head (2) comprises at least one first precursor nozzle (8) and at least one second precursor nozzle (10) arranged alternately successively and separated with gap, slit or opening forming the purge gas channel (12).

28. An apparatus according to claim 27, characterized in that the nozzle head (2) is a grate-like structure in which the first and second precursor nozzles (8, 10) form the rods and the purge gas channels (12) form the gaps between the rods.

Description:
Nozzle head

Background of the invention

The present invention relates to a nozzle head for subjecting a surface of a substrate to successive surface reactions of at least a first precursor and a second precursor, and particularly to a nozzle head according to the preamble of claim 1 . The present invention further relates to an apparatus according to the preamble of claim 20.

In the prior art several types of apparatuses, nozzle heads and nozzles are used for subjecting a surface of a substrate to successive surface re- actions of at least a first precursor and a second precursor according to the principles of atomic layer deposition method (ALD). In ALD applications, typically two gaseous precursors are introduced into the ALD reactor in separate stages. The gaseous precursors effectively react with the substrate surface, resulting in deposition of a growth layer. The precursor stages are typically fol- lowed or separated by an inert-gas purge stage that eliminates the excess precursor from the surface of the substrate prior to the separate introduction of the other precursor. Therefore an ALD process requires alternating in sequence the flux of precursors to the surface of the substrate. This repeated sequence of alternating surface reactions and purge stages between is a typical ALD de- position cycle.

The prior art apparatuses for continuously operating ALD usually comprise a nozzle head having one or more first precursor nozzles for subjecting the surface of the substrate to the first precursor, one or more second precursor nozzles for subjecting the surface of the substrate to the second precur- sor, one or more purge gas channels and one or more discharge channels for discharging both precursors and purge gas arranged in the following order: at least a first precursor nozzle, a first discharge channel, purge gas channel, a discharge channel, a second precursor nozzle, a discharge channel, a purge gas channel and a discharge channel, optionally repeated a plurality of times. The problem with this prior art nozzle head is that it comprises several different nozzles and channels which makes the nozzle head complicated and rather large. The nozzle is preferably moved in relation to the substrate for producing a number of growth layers.

Another type of prior art nozzle head for continuous ALD comprises alternatively in succession: a first precursor nozzle, a purge gas channel, a second precursor nozzle and purge gas channel, optionally repeated a plurality of times. In this prior art nozzle head each of the precursor nozzles and purge gas channels is provided with an inlet port and an outlet port such that the precursor and the purge gas is both supplied and discharged using the same nozzle. Therefore there are no separate discharge channels. The problem with this prior art nozzle head is that purge gas will leak to the precursor nozzle such that the precursor concentration will dilute. Thus the nozzle head is unable to provide a uniform gas supply over the whole length of the precursor nozzle or over the whole output face of the nozzle head. Furthermore the construction is complicated as there are inlet port and outlet port in each of the nozzles. Also this nozzle head may be moved relative to the substrate for producing a number of growth layers.

Brief description of the invention

Thus the object of the present invention is to provide a nozzle head and an apparatus such that the above mentioned prior art problems are solved. The objects of the present invention are achieved with a nozzle head according to the characterizing part of claim 1 , characterized in that the supply channels, purge gas channels and the discharge channels are longitudinal and arranged in succession in the following order: a purge gas channel, a first sup- ply channel, a discharge channel, a purge gas channel, a second supply channel and a discharge channel, optionally repeated a plurality of times. The objects of the present invention are achieved with an apparatus according to the characterizing part of claim 1 .

The preferred embodiments of the present invention are described in dependent claims.

The basic idea of the present invention is that the nozzle head comprises six gas elements such that there is always one purge gas channel and one vacuum discharge between two precursor nozzles. The precursor nozzles, purge gas channels and the vacuum discharge nozzles may all be separate elements in the nozzle head. Alternatively, the nozzle head may provided with precursor nozzles comprising two adjacent parallel extending channels having an open portion on the outlet face of the nozzle head. The precursor nozzle comprises an elongated supply channel arranged to supply precursor along the whole length of the supply channel and an elongated discharge channel extending adjacent to and parallel with the supply channel and arranged to discharge precursor along the whole length of the discharge channel. There- fore in the present invention the precursor flows in the nozzle from the supply channel to the discharge channel. In one preferred embodiment of the present invention the precursor nozzle is further provided with a reaction space arranged between the supply channel and the discharge channel. The reaction space is open to the output face of the nozzle head for subjecting the surface of the substrate to precursor and arranged to extend substantially along the whole length of the supply channel and the discharge channel. In one embodiment of the present invention the purge gas channels are arranged in fluid connection with the atmosphere surrounding the nozzle head such. Further- more, the discharge channels are arranged to exhaust both precursors and purge gas from the output face.

The present invention has the advantage that it provides a uniform precursor supply and also uniform discharge or precursor and purge gas over the whole length of the precursor nozzle. The present invention further enables the precursor to be supplied substantially perpendicularly against the surface of the substrate. This has the advantage that the perpendicular gas flow helps to break the gas layer on the substrate surface enhancing surface reactions of the precursors. Furthermore the present invention provides a nozzle head which has two vacuum discharges less than the prior art solutions. Further- more, the as the purge gag channel is in passive fluid connection with the atmosphere surrounding the nozzle head, the purge gas do not need to be specially supplied output face.

Brief description of the figures

In the following the invention will be described in greater detail, in connection with preferred embodiments, with reference to the attached drawings, in which

Figure 1A a schematic cross sectional view of an embodiment of a nozzle head;

Figure 1 B is a top view of the nozzle head of the apparatus of figure

1A;

Figure 2 is a schematic cross sectional view another embodiment of a nozzle head;

Figure 3 is a schematic top view of yet another embodiment of a nozzle head of figure 1A; Figure 4 shows a cross sectional view of still another embodiment of a nozzle head; and

Figure 5 shows a cross sectional view of one embodiment of a nozzle of a nozzle head.

Detailed description of the invention

Figure 1 shows a cross sectional view of one embodiment of an apparatus for subjecting a surface 4 of a substrate 6 to successive surface reactions of at least a first precursor A and a second precursor B according to the principles of ALD. The first and second precursors A and B may be any gaseous precursors used in ALD, such as ozone, TMA (trimethylaluminium), water, TiCI 4 , DEZ (diethylzinc), or precursor may also be plasma, such as NH 3 , Ar, O 2 , N 2 , H 2 or CO 2 plasma. The apparatus comprises a process chamber 26 having inside a gas atmosphere 14. The gas atmosphere 14 may comprise in- ert gas, such as nitrogen, or dry air, or any other gas suitable to be used as purge gas in ALD method. Also plasma may be used for purging, for example nitrogen or argon plasma. In that this context purge gas comprises also plasma. The purge gas source is connected to process chamber 36 for supplying purge gas into the process chamber 26. A nozzle head 2 is arranged inside the process chamber 26. The nozzle head comprises an output face 5, one or more first precursor nozzles 8 for subjecting the surface 4 of the substrate 6 to the first precursor A and one or more second precursor nozzles 10 for subjecting the surface 4 of the substrate 6 to the second precursor B. The apparatus further comprises means for supplying the first and second precursor A, B to the nozzle head 2 as well as means for discharging the first and second precursor A, B from the nozzle head 2. As shown in figure 1 A, the first and second nozzles are arranged alternatively is succession for subjecting the surface 4 of the substrate 6 to alternative surface reactions of the first precursor A and second precursor B as the substrate 6 and the nozzle head 2 move relative to each other. The apparatus may be provided such that the nozzle head 2 may be moved, for example back and forth, and the substrate 2 is stationary. Alternatively the nozzle head 2 is static and the substrate 6 is moved or also the both substrate 6 and the nozzle head 2 may be moved. The substrate 6 may be a separate substrate loaded into the process chamber and processed by batch processing or alternative substrates may be arranged to be transported through the process chamber 26. The apparatus may also be constructed for roll to roll -process such that a flexible substrate is transported from one roll through the process chamber 26 to another roll, or from any source through the process chamber 26 to any receptacle, and processed with the nozzle head 2 inside the process chamber 26.

The precursor nozzles 8, 10 are preferably elongated. The first precursor nozzle 8 is provided with a first channel 3 extending the longitudinal direction of the first precursor nozzle 8 and comprising a first open portion 9 extending along the first channel 3 and open to the output face 5 of the nozzle head 2. The second precursor nozzle 10 is provided with a second channel 7 extending the longitudinal direction of the second precursor nozzle 10 and comprising a second open portion 1 1 extending along the second channel 7 and open to the output face 5 of the nozzle head 2. As shown in figure 1 B the first precursor nozzle 8 comprises a first inlet port 18 for supplying first precursor A to the first channel 3 and two first outlet ports 20 for exhausting the sec- ond precursor from the first channel 3 after the surface reactions of the first precursor A. Similarly the second precursor nozzle 10 comprises a second inlet port 22 for supplying second precursor B to the second channel 7 and two second outlet ports 24 for exhausting the second precursor from the second channel 7 after the surface reactions of the second precursor B. In this em- bodiment the inlet ports 18, 22 are arranged in the middle of the length of the first and second channel 3, 7 and the outlet ports 20, 24 are arranged to the opposite ends of the first and second channel 3, 7, as shown in figure 1 B. However, it should be noted that there may also be two or more inlet ports 18, 22 and one or more outlet ports 20, 24 in the first and second channel 3, 7. The inlet ports 18, 22 and the outlet ports 20, 24 may also be situated in any other position in the first and second channel 3, 7.

As shown in figure 1A and 1 B, the first and second nozzles 8, 10 are separated from each other by purge gas channels 12 open to the gas atmosphere 14 surrounding the nozzle head 2 in the process chamber 26 and to the output face 5 of the nozzle head 2. The purge gas channels 12 are formed as gaps extending between the first and second precursor nozzles 8, 10. The gaps 12 thus provide a fluid connection to the gas atmosphere 14 comprising purge gas. The gaps form a purge gas channel 12 between the first and second precursor nozzles 8, 10 for separating the first and second nozzles 8, 10 and first and second precursors A, B from each other. In figures 1 A and 1 B the nozzle head 2 is provided as a grate-like structure in which the first and second precursor nozzles 8, 10 form the rods and the purge gas channels 12 form the gaps between the rods. The precursor nozzles 8, 10 are engaged to one another by connectors 33. However it should be noted that the purge gas channel 12 may also be provided by one or more channels, holes or conduits hav- ing a passive fluid connection to the gas atmosphere 14 or at least partly open to the gas atmosphere 14. These channels may be similar to first and second channels 3, 7.

In a preferred embodiment the first precursor nozzles 8 are arranged to operate at a first pressure at the output face 5, and the second pre- cursor nozzles 10 are arranged to operate at a second pressure at the output face 5. The gas atmosphere 14 is provided to a third pressure higher than the first and second pressure. Thus the purge gas in the gas atmosphere 14 flows to the purge gas channel 12 and keeps the first and second precursor A, B separated. Some purge gas will also flow to the first and second channels 3, 7 from the purge gas channel between the output face 5 of the nozzle head 2 and the surface 4 of the substrate 6. The first, second and third pressure may be lower than the normal air pressure (NTP; 1 bar, 0 °C), or substantially the same as the normal air pressure or higher than the normal air pressure or even at vacuum. The pressure differences of the nozzles and the atmosphere is the key factor. The first and second pressure are measured at the output face 5 of the nozzle head 2 and the pressure in the first and second channel may be different from the first and second pressure, normally higher than the first and second pressure.

Figure 2 shows another embodiment of the nozzle head 2 in which nozzle head 2 is provided with a separate purge gas container 39 arranged around the nozzle head 2. The purge gas container 39 has a gas atmosphere 16 inside. In figure 2 the purge gas container 39 is arranged to the nozzle head 2 and the gas atmosphere inside the purge gas container comprises purge gas. In this embodiment the first and second precursor nozzles 8, 10 are simi- lar to precursor nozzles of figures 1 A and 1 B, therefore they are not described in detail. In figure 2 there is provided a purge gas channel 12 between the first and second precursor nozzles 8, 10 for subjecting the surface 4 of the substrate 6 to a purge gas and separating the first and second precursor A, B from each other. The purge gas channel 12 is a channel extending in parallel with first and second precursor nozzles 8, 10. The purge gas channels 12 are arranged in passive fluid connection to the gas atmosphere 16 of the purge gas container 39 though conduits 35 extending from the purge gas container 39 to the purge gas channel 12. A purge gas source may be connected to the purge gas container 39 for supplying purge gas into the purge gas container 39. The purge gas channel 12 may also be formed by one or more gaps, holes or openings in passive fluid connection to the purge gas container 39 and at least partly open to the output face 5 of the nozzle head 2. The edge areas of the output face 5 are further provided with additional purge gas channels 12, as shown in figure 2. These additional purge gas channels 12 separate the nozzle head 2 and particularly the output face 5 of the nozzle head from the ambient atmosphere such that the nozzle head 2 may also optionally be used in atmospheric pressure as precursor gases are prevented from flowing to the ambient atmosphere. The additional purge gas channels may be provided separately to every edge area of the output face or they can extend as rings on the edge area and around the whole output face 5.

Also in this embodiment the first precursor nozzles 8 are arranged to operate at a first pressure at the output face 5, and the second precursor nozzles 10 are arranged to operate at a second pressure at the output face 5. The purge gas container 39 is arranged to a third pressure higher than the first and second pressure in the same way as in embodiment of figures 1A and 1 B. The first and second nozzles 8, 10 may also be operated in similar pressures as described in connection to figures 1A and 1 B. As the third pressure is higher than the first and second pressure the purge gas container provides a static supply of purge gas to the purge gas channels 12. Furthermore it should be noted that the nozzle head 2 of figure 2 may also be constructed such that the purge gas channels 12 are in fluid connection with the gas atmosphere 14 surround the nozzle head 2. Then the conduits 35 may be connected to the gas atmosphere 14 instead of purge gas container 39. The precursors and purge gas may be supplied to the nozzle head 2 via fluid connections. Alternatively the nozzle head 2 is provided with one or more precursor and/or purge gas containers, bottles or the like such that the precursors and/or the move together with the nozzle if the nozzle head is moved. This arrangement decreases the number of difficult fluid connections to a moving nozzle head 2.

The invention of figures 1A, 1 B and 2 may also be constructed using any kind of precursor nozzles and purge gas channels. The purge gas chan- nels may be formed by two or more separate holes, openings or any kind of features providing a fluid connection to the gas atmosphere 14 or a separate purge gas container 39. The embodiment of figures 1A, 1 B and 2 enables purge gas to be used to separate precursor nozzles from each other without actively supplying purge gas and using a same kind of nozzle structure as the precursor nozzles 8, 10.

A prior art way of constructing a nozzle head of figure 2 is to provide a first precursor nozzle having at least one first inlet port and at least one first outlet port, a second precursor nozzle having at least one second inlet port and at least one second outlet port, and a purge gas channel between the first and second precursor nozzles, the purge gas channel having only one or more third inlet ports and no outlet ports. These three nozzle are repeated one or more times to form a nozzle head. The purge gas supplied to the purge gas channel from third inlet ports is discharge through first and second outlet ports of the first and second precursor nozzles.

Figure 3 shows another embodiment in which the nozzle head 2 has the same kind of structure as the nozzle head of figures 1A and 1 B. It should be noted that the nozzle head may also be constructed in some other way than in figure 3. The nozzle head 2 comprises two or more first precursor nozzles 8 for subjecting the surface of the substrate to the first precursor A and two or more second precursor nozzles 10 for subjecting the surface 4 of the substrate 6 to the second precursor B. The first precursor nozzle 8 comprises at least one first inlet port 18 for supplying the first precursor A and at least one first outlet port 20 for exhausting the first precursor A. In figure 3 the first precursor nozzle head 8 comprises one first inlet port 18 provided at one of the elongated first precursor nozzle 8 and one first discharge port 20 provided at the other end of the first precursor nozzle 8. Similarly the second precursor nozzle 10 comprises one second inlet port 22 provided at one of the elongated second precursor nozzle 10 for supplying the second precursor B and one second discharge port 24 provided at the other end of the second precursor nozzle 10 for exhausting the second precursor B. The inlet ports 18, 22 and the outlet ports 20, 24 may also be located in on other way, for example as in figure 1 B, the there may be also two or more inlet ports and outlet ports in each nozzle 8, 10. Furthermore, as will be described later, the nozzle head may also be constructed such that the precursor nozzles 8, 10 do not comprise any outlet ports 20, 24, but the nozzle head is provided with one or more separate discharge channels. In figure 3 the nozzle head 2 is provided with first connection elements 30 for conducting first precursor A from the one first precursor nozzle 8 to the one or more other first precursor nozzles 8. The nozzle head 2 is further provided with second connection elements 32 for conducting second precursor B from the one second precursor nozzle 10 to the one or more other second precursor nozzles 10. The connection elements 30, 32 preferably comprise a pipe, a piping, a closed channel or a conduit and any other necessary components for providing a fluid connection between the two or more first precursor nozzles 8 or two or more second precursor nozzles 10. As shown in figure 3 the first outlet port 20 of one first precursor nozzle 8 is connected the first inlet port 18 of another first precursor nozzle 8 with the first connection element 30 for conducting first precursor A from the one first precursor nozzle 8 to the other first precursor nozzle 8. Similarly the second outlet port 24 of one second precursor nozzle 10 is connected to the second inlet ports 22 of another sec- ond precursor nozzles 10 with the at least one second precursor nozzle 10 for conducting second precursor B from the one second precursor nozzle 10 to the another second precursor nozzle 10. According to the above mentioned the idea of this is to connect two or more precursor nozzles 8, 10 in series such that precursor may flow in succession through two or more precursor nozzles 8, 10.

It should be noted that the connection elements 30, 32 may also be arranged some other way than as shown in figure 3 in which each connection element 30, 32 is provided between two or more precursor nozzles 8 or 10. The first connection element 30 may be arranged between one first precursor nozzle 8 and two or more other first precursor nozzles 8 for conducting first precursor A from the one first precursor nozzle 8 to two or more other first precursor nozzles 8. Also the second connection element 32 may be arranged between one second precursor nozzle 10 and two or more other second precursor nozzles 10 for conducting second precursor B from the one second pre- cursor nozzle 10 to two or more other second precursor nozzles 10.

The embodiment of figure 3 and as described above provides way for enhancing the material efficiency of the precursors A, B. When precursor A, B is supplied to a precursor nozzle 8, 10 some of the precursor A, B reacts of the surface 4 of the substrate 6, but usually an overdose of precursor A, B is supplied. Thus at least part of the precursor A, B supplied to the precursor channel 8, 10 does not react on the substrate 6 surface. In the prior art this ex- cess precursor A, B is discharged as waste. The embodiment of figure 3 enables the excess precursor A, B to be used in some other precursor nozzle 8, 10. It should also be noted that the fluid connection with the connection element 30, 32 may be formed in different ways depending on the structure of the nozzle head 2. Furthermore, it should be noted that the there is a pressure drop when precursor is conducted from one precursor nozzle 8, 10 to another.

The first connection element 30 may be arranged between one or more first precursor nozzles 8 and at least another first precursor nozzle 8. Thus one first precursor nozzle 8 may be connected to several other first pre- cursor nozzles 8, or several first precursor nozzles 8 may be connected to one other first precursor nozzles 8, or several first precursor nozzles 8 may be connected to several other first precursor nozzles 8 using the first connection elements 30. In one embodiment the nozzle head 2 comprises two or more first connection elements 30 between two first precursor nozzles 8. Thus pre- cursor is conducted from one first precursor nozzle 8 to another first precursor nozzle 8 and the discharged. The nozzle head 2 may thus comprise two or more these together connected units of two first precursor nozzles 8. The second precursor nozzles 10 may be connected in the same way using the second connection elements 32.

Figure 4 shows a schematic view of one embodiment in which the nozzle head comprises first precursor nozzles 8, second precursor nozzles 10 and purge gas channels 12 provided between the elongated precursor nozzles 8, 10. The precursor nozzles 8, 10 comprise a supply channel 40, 44 extending in the longitudinal direction of the elongated precursor nozzle 8, 10. The precursor nozzles 8, 10 further comprises a discharge channel 42, 46 extending in the longitudinal direction of the elongated precursor nozzle 8, 10 substantially parallel and adjacent to the supply channel 40, 44 for discharging precursor A, B by using vacuum or suction. The first precursor nozzle 8 comprises a first supply channel 40 and a first discharge channel 42, while the second precursor nozzle 10 comprises a second supply channel 44 and a second discharge channel 46. Therefore, figure 4 shows an embodiment in which the supply channel 40, 44 and the discharge channel 42, 46 are provided to the same precursor nozzle 8, 10 and separated from each other by a partition wall 52. However, it should be noted that the discharge channels 42, 46 may also be formed as a separate structural part arranged between a precursor nozzle 8, 10 or supply channel 40, 44 and the purge gas channel 12. The supply channel 40, 44 is provided with at least one inlet port for supplying precursor A, B through the output face 5 of the nozzle head 2. The inlet ports are preferable arranged such that precursor A, B may be supplied along the whole length of the supply channel 40, 44. Then the discharge chan- nel 42, 46 is provided with at least one outlet port for discharging precursor A, B. The outlet ports are preferably arranged such that the precursor A, B may be discharged along the whole length of the discharge channel 42, 46. Therefore the inlet port and the outlet port may be a longitudinal opening extending along the supply channel 40, 44 and discharge channel 42, 46 respectively. Alternatively the supply channel 40, 44 and discharge channel 42, 46 may comprise series of inlet ports and outlet along the length of the supply channel 40, 44 and discharge channel 42, 46, respectively. As seen in figure 4 the supply channel 40, 44 and the discharge channel 42, 46 are at least partly open to the output face 5. The supply channel 40, 44 is provided with a supply opening 47, 48 extending the longitudinal direction of the supply channel 40, 44 and being open to the output face 5. Also the discharge channel 42, 46 is provided with a discharge opening 43, 45 extending the longitudinal direction of the discharge channel 42, 46 open the output face 5. The precursor nozzle 8, 10 or the supply channel 40, 44 is arranged to supply precursor A, B substantially perpen- dicularly to the output face 5, and precursor nozzle 8, 10 or the discharge channel 42, 46 is arranged to discharge precursor A, B substantially perpendicularly to the output face 5. This has the advantage that the perpendicular gas flow helps to break the gas layer on the substrate surface enhancing surface reactions of the precursors.

It should be noted that the embodiment of figure 4 may also be constructed such that the supply channel 40, 44 is part of the precursor nozzle 8, 10, but the discharge channel 42, 46 is a separate part. The basic idea is that the nozzle head 2 comprises on the output face 5 supply channels 40, 44, purge gas channels 12 and the discharge channels 42, 46 in succession in the following order: at least a first supply channel 40, a first discharge channel 42, purge gas channel 12, a second supply channel 44, a second discharge channel 46 and a purge gas channel 12, optionally repeated a plurality of times. It is irrelevant if the supply channel 40, 44 and the discharge channel 42, 46 are provided to same structural part or not. The purge gas channel 12 may be pro- vided in the same as in the embodiment of figures 1A, 1 B, 2 and 3 or the purge gas channels 12 may be provided with same kind of nozzles as the precursor nozzles 8, 10 or supply channels 40, 44. Thus the purge gas channel 12 may be arranged in passive fluid connection with a purge gas atmosphere 14, 16 for subjecting the surface 4 of the substrate 6 to a purge gas, as shown in figure 1A, 1 B and 2. All what is said in connection with figure 1A, 1 B and 2 con- cerning the purge gas channel 12 apply also for embodiments of figure 4 and 5. The purge gas atmosphere is the gas atmosphere 14 surrounding the nozzle head 2 or a separate purge gas container 39. The one or more first precursor nozzles 8 is arranged to operate at a first pressure at the output face 5, and that the one or more second precursor nozzles 10 are arranged to operate at a second pressure at the output face 5, and that the purge gas atmosphere is arranged to a third pressure higher than the first and second pressure. The first and second pressures may also be measured at the output face 5 between the supply channel and the discharge channel in embodiment of figure 4. Thus the discharge channel 42, 46 may exhaust both the precursors and the purge gas from the output face 5.

Figure 5 shows one embodiment in which the nozzle head 2 comprises a reaction space 50 provided between the supply channel 40, 44 and the discharge channel 42, 46. The reaction space 50 is open to the output face 5 for subjecting the surface 4 of the substrate 6 to precursor A, B. In figure 4 is shown a precursor nozzle similar to figure 4 in which the discharge channel 42, 46 is formed to the precursor nozzle 8. However, it should be noted that the reaction space 50 may also be provided between a precursor nozzle 8, 10 having only supply channel 40, 44 and a separate discharge channel 42, 46. The reaction space 50 is arranged between the supply channel 40, 44 and the dis- charge channel 42, 46. The reaction space 50 is arranged to extend substantially along the whole length of the supply channel 40, 44 and between the output face 5 and the supply and discharge channels 40, 44, 42, 46. The reaction space 50 is arranged such that precursor A, B is arranged to flow from the supply channel 40, 44 through the reaction space 50 to the discharge channel 42, 46 and the surface reactions of the precursors A, B take place at the reaction space 50.

The nozzle head 2 of figure 4 comprising on the output face 5 precursors nozzles 8, 10, purge gas channels 12 and the discharge channels 42, 46 in succession in the following order: at least a first precursor nozzle 8, a first discharge channel 42, purge gas channel 12, a second precursor nozzle 10, a second discharge channel 46 and a purge gas channel 12, optionally repeated one or more times, may be also constructed to comprise one or more connection elements 30, 32 shown in embodiment of figure 3. Thus the one or more first discharge channel 42 following one first precursor nozzle 8 or first supply channel 40 is connected to one or more other first precursor nozzle 8 or first supply channel 40 for conducting first precursor A to the one or more other first precursor nozzles 8 or first supply channels 40. Similarly the one or more second discharge channel 46 following one second precursor nozzle 10 or second supply channel 44 is connected to one or more other second precursor nozzle 10 or second supply channel 44 for conducting second precursor B to the one or more other second precursor nozzle 8 or second supply channel 44.

From the above description it should be evident that all the embodiment disclosed and shown in figures 1 A, 1 B, 2, 3, 4 and may be combined

It should be obvious to a person skilled in the art that as the technology advantages, the inventive concept can be implemented in variety of ways. The invention and its embodiments are not restricted to the above examples, but may vary within the scope of the claims.