WO2012028776A1

WO2012028776A1 - Apparatus

Info

Publication number: WO2012028776A1
Application number: PCT/FI2011/050743
Authority: WO
Inventors: Jari Sinkko
Original assignee: Beneq Oy
Current assignee: Beneq Oy
Priority date: 2010-08-30
Filing date: 2011-08-25
Publication date: 2012-03-08
Anticipated expiration: 2013-02-28
Also published as: TW201219596A; CN103108985A; FI20105906A0; CN103108985B

Abstract

The present invention relates to an apparatus for processing a surface (4) of a flexible substrate (6). The apparatus comprising transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) for transporting the substrate (6) and at least one nozzle head (2) comprising two or more precur- sor zones (14, 16) for subjecting the surface (4) of the substrate (6) to at least first and second precursors. Ac- cording to the invention the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) comprises a transport cylinder (8) and the nozzle head is formed as a nozzle head cylinder (2) arranged around the transport cylinder (8) for trans- porting and processing the substrate (6) between the transport cylinder (8) and the nozzle head cylinder (2).

Description

Apparatus

Background of the invention

The present invention relates to an apparatus for processing a surface of a flexible substrate by subjecting the surface of a substrate to succes- sive surface reactions of at least a first precursor and a second precursor, and particularly to an apparatus according to the preamble of claim 1 .

In the prior art several types of apparatuses and nozzle heads are used for subjecting a surface of a substrate to successive surface reactions 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 single atomic layer. The precursor stages are typically followed or separated by a 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 deposition cycle.

The prior art ALD-apparatuses usually comprise a nozzle head having one or more first precursor zones for subjecting the surface of the substrate to the first precursor, one or more second precursor zones for subjecting the surface of the substrate to the second precursor, and one or more purge gas zones or purge gas zones arranged between the first and second precursor zones for subjecting the surface of the substrate to a purge gas. The zones are arranged alternatively in succession to the nozzle head: first precursor zone, purge gas zone, second precursor zone, purge gas zone, first precursor zone, purge gas zone, second precursor zone, and so on. Therefore when the nozzle head is moved on the substrate surface it will produce growth layers according to the principles of ALD method. The nozzle head may also comprise discharge channels arranged between the first and second precursor zone or between a first precursor zone and a purge gas zone or between a second precursor zone and a purge gas zone. The discharge channel is arranged to exhaust precursor and purge gas after the surface of the substrate is subjected to it. Alternatively each of these prior art precursor zones and purge gas zones comprise at least one inlet port for supplying the precursor or purge gas and at least one outlet port for exhausting the precursor or purge gas. Thus there is provided suction to each of the zones for exhausting the precursor or purge gas after the substrate is subjected to it.

As only one atomic layer is produced on the surface of the substrate during one ALD-cycle, the nozzle head is formed to comprise several first and second zones such that a single scan with the nozzle head over the surface of the substrate forms several atomic layers on the surface of the substrate. The single scan with the nozzle head may be done by moving either the nozzle head or the substrate. In the prior art the number of scan with the nozzle head is increasing by moving the nozzle head back and forth using fast speed for performing multiple scans over the surface of the substrate. This prior art way for producing several atomic layer the disadvantage that the back and forth movement produces great mechanical forces the nozzle head has to withstand. The forces are especially high as the nozzle head has be stopped in the extreme position and accelerated again. Therefore the apparatus and the nozzle head are susceptible to damages.

Brief description of the invention

Thus the object of the present invention is to provide an apparatus such that the above mentioned prior art problems are solved. The objects of the present invention are achieved with an apparatus according to the characterizing portion of claim 1 , characterized in that a transport mechanism of the apparatus is arranged to guide substrate to the transport surface and from the transport surface.

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

The present invention is based on the idea of providing an apparatus a hollow cylindrical nozzle head having an output face on the inner cylinder surface and a transport surface conforming the output face such that a flexible substrate strip or web may be transported or guided in a gap, transportation path, between the output face and the transport surface and from the transport path. In other words the transport mechanism is arranged to guide a flexible elongated substrate to the transport surface and from the transport surface. In one embodiment the flexible substrate is supplied and guided to the transport surface from a first substrate roll and to a second substrate roll from the transport surface. The apparatus is further arranged such that the flexible substrate may be processed by subjecting a surface of the substrate to successive surface reactions according to the principles of atomic layer deposition when the substrate is transported along the transportation path between the output face and transport surface. A transport mechanism is arranged to transport the sub- strate to the transport surface substantially perpendicularly to the central axis of the nozzle head cylinder. The apparatus preferably comprises a transport mechanism having a transport cylinder comprising an opening for transporting the substrate to the transport surface substantially perpendicularly to the central axis of the nozzle head cylinder. The transport cylinder may be a hollow cylinder having the opening the cylinder mantle of the transport cylinder for transporting the substrate to the transport surface substantially perpendicularly to the central axis of the nozzle head cylinder. The transport cylinder is provided with a transport surface on the outer cylinder surface for transporting the substrate along the outer surface of the transport cylinder. Additionally, the nozzle head cylinder is provided with an output face on the inner cylinder surface for subjecting the surface of the substrate surface reactions of at least a first precursor and a second precursor. The nozzle head cylinder is arranged around the transport cylinder such that the transport surface and the output face are opposite to each other for processing the surface of the substrate by transporting the substrate along the transport surface.

The present invention has the advantage that it provides an apparatus which enables to use rotational movement for subjecting the surface of the flexible substrate to the precursors. In the present invention both the flexible substrate and the nozzle may be arranged to utilize rotational movement. The rotational movement decreases the stresses and forces subjected to the apparatus compared to back and forth movement of the nozzle head. The present invention thus also provides efficient coating as rotational movement enables higher movement speeds for the nozzle head. Furthermore, the present invention enhances the usage of floor area as the substrate is guided to a cylindrical path instead of conventional horizontal path. The present invention also provides an apparatus in which the substrate may be supplied to a circular transport path uniformly substantially perpendicularly to the central axis of a cylindrical nozzle head. 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 1 is a schematic view showing one embodiment of the apparatus according to the present invention.

Detailed description of the invention

Figure 1 shows schematically one embodiment of the apparatus of the present invention. The apparatus comprises two cylinders 8, 2 arranged inside each other. The inner cylinder is a transport cylinder 8 having an inner surface and outer surface. The outer surface of the transport cylinder 8 is a transports surface 3 along which a flexible substrate 6 is guided such that it passes a cylindrical path. The apparatus further comprises an outer cylinder 2 formed as a nozzle head cylinder 2 for supplying precursors such that the surface 4 of the substrate 6 is subjected to successive surface reactions by the precursors. As shown in figure 1 , the nozzle head cylinder 2 arranged around the transport cylinder 8 for transporting and processing the substrate 6 between the transport cylinder 8 and the nozzle head cylinder 2. Therefore there is a gap between the transport cylinder 8 and the nozzle head cylinder 2 and the substrate 6 is arranged to be transported in an at least partly cylindrical or circular transport path in the gap between the cylinders 8, 2. 21 . The nozzle head cylinder 2 may comprise gas connections arranged axially or coaxially to the central axis of the nozzle head cylinder 2 for supplying and/or discharging process gases. The nozzle head cylinder 2 may also comprise a bottom (not shown) which may be used for arranging the gas connections axially or coaxially to the central axis of the nozzle head cylinder 2.

The flexible substrate 6 may be any elongated and flexible substrate that may be guided to a circular path. In this context the substrate means a substrate itself or a powder like, particle like or separate parts or objects installed on an elongated and flexible substrate carrier. The precursors used may comprise any precursors suitable for atomic layer deposition, such as ozone, TMA (trimethylaluminium), water, TiCI₄, DEZ (diethylzinc), or precursor may also be plasma, such as NH₃, Ar, O₂, N₂, H₂ or CO₂ plasma. Purge gas used in the nozzle head cylinder 2 may comprise inert gas, such as nitrogen, dry air, or any other gas suitable to be used as purge gas in atomic layer deposition. Also plasma may be used for purging, for example nitrogen or argon plasma. In that this context purge gases and precursors comprise also plasma.

According to figure 1 , the apparatus comprises a transport mecha- nism including the transport cylinder 8 for transporting the substrate 6 and at least one nozzle head nozzle head cylinder 2 having two or more precursor zones 14, 16 for subjecting the surface 4 of the substrate 6 to at least first and second precursors. As mentioned above the transport cylinder 8 is provided with a transport surface 3 on the outer cylinder surface for transporting the substrate 6 along the outer surface of the transport cylinder 8. Accordingly, the nozzle head cylinder 2 is provided with an output face 5 on the inner cylinder surface for subjecting the surface 4 of the substrate 6 surface reactions of at least a first precursor and a second precursor. As shown in figure 1 , the nozzle head cylinder 2 is arranged around the transport cylinder 8 such that the trans- port surface 3 and the output face 5 are opposite to each other for processing the surface 4 of the substrate 6 by transporting the substrate 6 along the transport surface 3. There is provided gap between the transport surface 3 and the output face 5. The gap forms the transports path along which the substrate 6 is transported between the transport cylinder 8 and the nozzle head cylinder 2. Therefore, a reaction space is formed between the transport surface 3 and the output face 5. Then the substrate 6 moves along the transport surface 3 the substrate surface 4 and the output face 5 for a reaction space.

The transport mechanism of the apparatus comprises preferably one or more transport elements provided to the transport surface 3 for guiding the substrate 6 along the transport surface 3 and enhancing the movement of the substrate 6. In the embodiment of figure 1 , the transport elements are formed as transport rollers 10 extending substantially in the direction of the central axis of the cylinders 2, 8. The transport rollers 10 may be freely rotating rollers or driven rollers. The transport element may also be for example a con- veyor belt or slide surface.

As shown in figure 1 the apparatus comprises a first and second substrate roll 20, 22. The substrate 6 may is supplied from the first substrate roll 20 to the transport path between the cylinders 2, 8 to be processed and from the transport path to the second precursor roll 22. The substrate 6 may also be further supplied in the same way from the second substrate roll 22 to the first substrate roll 20. Furthermore, the substrate 6 may be driven two or more times through the transport path between the first and second substrate roll 20, 22. The substrate rolls 20, 22 may be driven such that they provide a force for moving the substrate 6 through the transport path. It should be noted that the substrate rolls 2, 8 may be part of the apparatus or they may be sepa- rate parts that may be connected to the apparatus. The substrate rolls 20, 22 may also be replaced with some other kind of receptacles for storing, supplying and receiving substrate 6.

The transport mechanism of the apparatus further comprises guide elements for guiding the substrate 6 to a transport path between the transport cylinder 8 or the transport surface 3 and the nozzle head cylinder 2 and from the transport path or the transport surface 3. In the embodiment of figure 1 , the guide elements comprise one or more guide rollers 24, 26, 28, 30 for guiding the substrate 6 to the transport surface 3 and from the transport surface 3. In figure 1 , guide rollers 24, 26 are arranged to guide the substrate 6 to opening 32 provided to the transport cylinder 8 and to a first transport roller 28 in the transport surface 3. The opening 32 goes through the wall of the hollow transport cylinder 8 and extends in the direction of the central axis of the transport cylinder 8. The last transport roller 30 and the second substrate roll 22 are arranged such that the substrate 6 may be guided from the transport surface 3 directly to the second substrate roll 22. However, it should be noted that the guide elements, guide rollers 24, 26, 28, 30 and the first and second substrate rolls 20, 22 may also be arranged in a different manner and the present invention is not limited to the arrangement of the guide elements, guide rollers 24, 26, 28, 30 and the first and second substrate rolls 20, 22. Thus the transport mechanism may comprise one or more guide rollers, guide surfaces or other guide elements for guiding the substrate 6 to the transport surface 3 and from the transport surface 3.

As seen in figure 1 , the transport path of the substrate 6 between the cylinders is close to 360 degrees. Only the width of the opening 32 is taken out of the whole circle. However, the transport path between the cylinders and the transport mechanism may also be arranged to transport the substrate 6 at least 180 degrees, preferably at least 270 and more preferably at least 330 degrees along the transport surface 3. It should be noted that the transport cylinder 8 is shown in figure 1 as a hollow cylinder having a sector 32 cut off. The opening may thus be also 90 degrees or even 180 degrees. In this context the term transport cylinder comprises all these alternatives. Therefore, the trans- port cylinder 8 may also be only part of a cylinder, such as 270 degrees or 180 degrees of cylinder or of cylindrical wall of a cylinder. Thus the transport cylinder may comprise a transport surface which is only part of the cylindrical wall. It also should be noted that the opening does not have to be slit as in figure 1 , but it may also be a hole in the mantle of the transport cylinder. The opening 32 enables the substrate 6 to be transported to the transport surface 3 substantially perpendicularly to the central axis of the nozzle head cylinder 2.

Figure 1 shows also a detailed cross sectional view of the nozzle head cylinder 2. The nozzle head cylinder 2 comprises on the inner surface, on the output face 5, in succession in the following order: a purge gas zone 13, a precursor zone 14, 16 and a discharge zone 1 1 , optionally repeated a plurality of times. The purge gas zone 13, precursor zone 14, 16 and the discharge zone 1 1 are arranged alternatively in succession in the direction of the circumference of the nozzle head cylinder 2. As shown in figure 1 the nozzle head cylinder 2 comprises on the output face 5 in succession in the following order: a first precursor zone 14, a discharge zone 1 1 , purge gas zone 13, a second precursor zone 16, a discharge zone 1 1 and a purge gas zone 13, optionally repeated a plurality of times. The precursors are supplied though the precursor zones 14, 16 for subjecting the surface to surface reactions of the precursors. Purge gas is supplied in the purge gas zone 13 and the precursors are discharged with the discharge zones 1 1 using suction or vacuum. The precursor zones 14, 16 may be formed as channels or slits or the like extending substantially the direction of the central axis of the nozzle head cylinder 2, as shown in figure 1 . In an alternative embodiment the channels 14, 16, 1 1 , 13 may be ar- ranged to extend in an angle relative to the direction of the central axis of the nozzle head cylinder 2. The angle between the channels 14, 16, 1 1 , 13 and the central axis may be from example 1 to 10 degrees. The precursor zone 14, 16 may also be provided by precursor nozzles arranged to supply precursors.

The arrangement of figure 1 provides a uniform gas flow along whole length of the precursor zone 14, 16 and the purge gas zone 13, and also a uniform discharge along the discharge zone 1 1 . Therefore the precursor zones 14, 16 may be provided as precursor nozzles 14, 16 supplying precursors along the whole length of the precursor zone. Also purge gas zone 13 may be provided as a purge gas nozzle supplying purge gas along the whole length of the purge gas zone and the discharge zone 1 1 is arranged to dis- charge precursors and purge gas along the whole length of the discharge zone.

In an alternative embodiment the output face is provided in succession in the direction of the circumference of the cylindrical nozzle head 2 in the following order: a first precursor zone 14, a purge zone 13, a second precursor zone 16 and a purge gas zone 13, optionally repeated a plurality of times. In this embodiment the first precursor zone 14 is provided with at least one first inlet port for supplying the first precursor and at least one first outlet port for discharging the first precursor, and the second purge gas zone 16 is provided with at least one second inlet port for supplying the second precursor and at least one second outlet port for discharging the second precursor, and the purge zone 13 is provided with at least one third inlet port for supplying purge gas. The purge gas zone 13 may also comprise one or more third outlets or alternatively purge gas may be discharged through the outlet ports of the precur- sor zones. The inlet ports may be located for example to one end of a longitudinal precursor channel and purge gas channel and the outlet ports may be located to another end of the precursor channel or purge gas channel such that the purge gas and precursors may flow along the channels. Alternatively the inlet ports may be located substantially in the middle of a channel and the out- let ports to the opposite ends of a channel.

As shown in figure 1 , the surface 4 facing the output face 5 of the nozzle head cylinder 2 is subjected alternatively in succession to precursor zones as it is transported along the transport path between the cylinders 2, 8. It should be noted that the output face 5 may comprise two or more precursor zones, but preferably the output face 5 comprises several precursor zones such that several growth layers may be provided on the surface 4 of the substrate 6 when it is transported through the transport path between the cylinders 2, 8.

The coating capacity of the apparatus may be further increased by rotating the nozzle head cylinder 2 around the central axis of the nozzle head cylinder 2. Thus the apparatus may comprise a rotating mechanism (not shown) for rotating the nozzle head cylinder 2 around the central axis of the nozzle head cylinder 2. The rotating mechanism may be arranged to rotate nozzle head cylinder 2 in the transport direction of the substrate 6 along the transport surface 3 or to the opposite direction in relation to the transport direction of the substrate 6 along the transport surface 3. When the nozzle head cyl- inder 2 is rotated in the transport direction of the substrate 6 along the transport surface 3 the nozzle head cylinder 2 should be rotated in speed higher than the transport speed of the substrate 6. Rotating the nozzle head cylinder 2 subjects the surface 4 of the substrate more times to the precursor zones 14, 16 during the time the substrate moves along the transport path. Thus more growth layers may be provided when the substrate is transported once through the transport path. 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.

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.

Claims

1 . An apparatus for processing a surface (4) of a flexible substrate (6) by subjecting the surface (4) of a substrate (6) to successive surface reac- tions of at least a first precursor and a second precursor, the apparatus comprising:

- at least one nozzle head (2) comprising two or more precursor zones (14, 16) for subjecting the surface (4) of the substrate (6) to at least the first and second precursors, and

- a transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) for transporting the substrate (6),

the nozzle head being formed as a nozzle head cylinder (2) provided with an output face (5) on the inner cylinder surface for subjecting the surface (4) of the substrate (6) to surface reactions of at least the first precur- sor and the second precursor, and

the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) comprising a transport surface (3) conforming at least partly the output face (5) of the nozzle head cylinder (2) for transporting the substrate (6) between the output face (5) and the transport surface (3),

characterized in that the transport mechanism (20, 22, 24, 26, 28,

30, 8, 10) is arranged to guide substrate (6) to the transport surface (3) and from the transport surface (3).

2. An apparatus according to claim 1 , characterized in that the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) comprises an at least partly cylindrical transport cylinder (8) having the transport surface (3) on the outer cylinder surface and arranged inside the nozzle head cylinder (2) for transporting and processing the substrate (6) between the transport cylinder (8) and the nozzle head cylinder (2).

3. An apparatus according to claim 1 or 2, characterized in that the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) is arranged to transport the substrate (6) to the transport surface (3) substantially perpendicularly to the central axis of the nozzle head cylinder (2).

4. An apparatus according to claim 2 or 3, characterized in that the transport cylinder (8) comprises an opening (32) for transporting the substrate (6) to the transport surface (3) substantially perpendicularly to the central axis of the nozzle head cylinder (2).

5. An apparatus according to claim 4, characterized in that the transport cylinder (8) is a hollow cylinder having the opening (32) in the cylin- der mantle of the transport cylinder (8) for transporting the substrate (6) to the transport surface (3) substantially perpendicularly to the central axis of the nozzle head cylinder (2).

6. An apparatus according to any one of claims 1 to 5, characterized in that the transport surface (3) is provided with one or more transport elements (10) guiding the substrate (6) along the transport surface (3).

7. An apparatus according to claim 5, characterized in that the transport elements comprise transport rollers (10), a conveyor belt or a slide surface.

8. An apparatus according to any one of claims 1 to 7, character- ized in that transport mechanism comprises one or more guide elements (24,

26, 28, 30) for guiding the substrate (6) to the transport surface (3) the transport surface (3).

9. An apparatus according to claim 8, characterized in that the guide elements comprise one or more guide rollers (24, 26, 28, 30) or rods for guiding the substrate (6) to the transport surface (3) and from the transport surface (3).

10. An apparatus according to any one of claims 1 to 9, characterized in that transport mechanism comprises a first substrate roll (20) and a second substrate roll (22) between which substrate rollers (20, 22) the sub- strate (6) may be transported such that the substrate (6) is processed between the substrate rolls (20, 22).

1 1 . An apparatus according to any one of claims 1 to 10, characterized in that the nozzle head cylinder (2) is provided one or more first precursor zones (14) and one or more second precursor zones (16) arranged alterna- tively in succession in the direction of the circular circumference of the nozzle head cylinder (2).

12. An apparatus according to claim 1 1 , characterized in that the nozzle head (2) comprises on the output face (5) in succession in the following order: a purge gas zone (13), a precursor zone (14, 16) and a discharge zone (1 1 ), optionally repeated a plurality of times.

13. An apparatus according to claim 1 1 or 12, characterized in that the nozzle head cylinder (2) comprises on the output face (5) in succession in the following order: a first precursor zone (14), a discharge zone (1 1 ), purge gas zone (13), a second precursor zone (16), a discharge zone (1 1 ) and a purge gas zone (13), optionally repeated a plurality of times.

14. An apparatus according to claim 1 1 , characterized in that the output face (5) is provided in succession in the following order: a first precursor zone (14), a purge gas zone (13), a second precursor zone (16) and a purge zone (13), optionally repeated a plurality of times.

15. An apparatus according to claim 14, characterized in that the first precursor zone (14) is provided with at least one inlet port for supplying the first precursor and at least one outlet port for discharging the first precursor, and that the second precursor zone (16) is provided with at least one inlet port for supplying the second precursor and at least one outlet port for discharging the second precursor, and that the purge zone (13) is provided with at least one inlet port for supplying purge gas.

16. An apparatus according to any one of claims 1 1 to 15, characterized in that the precursor zones (14, 16) are formed by channels extending substantially the direction of the central axis of the nozzle head cylinder (2) or in an angle relative to the direction of the central axis of the nozzle head cylinder (2).

17. An apparatus according to any one of claims 1 to 16, characterized in that the apparatus comprises a rotating mechanism for rotating the nozzle head cylinder (2) or the transport cylinder (8) around the central axis of the nozzle head cylinder (2).

18. An apparatus according to claim 17, characterized in that the rotating mechanism is arranged to rotate nozzle head cylinder (2) or the transport cylinder (8) in the transport direction of the substrate (6) along the transport surface (3) or to the opposite direction in relation to the transport direction of the substrate (6) along the transport surface (3).

19. An apparatus according to any one of claims 1 to 18, characterized in that the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) is arranged to transport the substrate (6) at least 270 degrees along the transport surface (3).

20. An apparatus according to claim 19, characterized in that the transport mechanism (20, 22, 24, 26, 28, 30, 8, 10) is arranged to transport the substrate (6) at least 330 degrees along the transport surface (3).

21 . An apparatus according to any one of claims 1 to 20, character- ized in that the nozzle head cylinder (2) comprises gas connections arranged axially or coaxially to the central axis of the nozzle head cylinder (2) for supplying and/or discharging process gases.