Method and apparatus for sputtering a target material onto a substrate

Abstract

An apparatus for sputter deposition of a target material onto a substrate is disclosed. In one form, the apparatus comprises a substrate guide arranged to guide a substrate along a curved path and a target portion spaced from the substrate guide and arranged to support the target material. The target portion and the substrate guide define a deposition zone between them. The apparatus comprises a confinement device comprising one or more magnetic elements arranged to provide a confining magnetic field to confine a plasma in the deposition zone, thereby providing sputter deposition of the target material onto a substrate web in use, the confining magnetic field being characterized in that the magnetic field lines are arranged to substantially follow the curve of the curved path, at least in the deposition zone, thereby confining the plasma around the curve of the curved path.

Description

Technical Field

[0001] The present invention relates to deposition and, more particularly, to methods and apparatus for sputter depositing a target material onto a substrate. Background Art

[0002] Deposition is the process of depositing a target material on a substrate. An example of deposition is thin film deposition, in which a thin layer (usually from about one nanometer or even a fraction of a nanometer to several micrometers or even tens of micrometers) is deposited on a substrate, such as a silicon wafer or a coil. An example technique for thin film deposition is physical vapor deposition (PVD), in which a target material in a condensed phase evaporates to produce a vapor that then condenses onto the substrate surface. An example of PVD is sputtering deposition, in which particles are ejected from a target due to the bombardment of energetic particles (such as ions). In an example of sputtering deposition, a sputtering gas, such as an inert gas such as argon, is introduced into a vacuum chamber at low pressure, and the sputtering gas is ionized using energetic electrons to produce a plasma. The bombardment of the ions of the plasma on the target ejects the target material, which can then be deposited on the substrate surface. Sputtering deposition is superior to other thin film deposition methods, such as evaporation, because the target material can be deposited without heating the target material, which in turn can reduce or prevent thermal damage to the substrate.

[0003] One known sputtering deposition technique employs a magnetron, in which a glow discharge is combined with a magnetic field that causes an increase in plasma density in a circular region near the target. The increase in plasma density results in an increase in deposition rate. However, the use of a magnetron results in a circular "racetrack" shaped erosion profile of the target, which limits the utilization of the target and can negatively affect the uniformity of the resulting deposition.

[0004] It would be desirable to provide uniform and / or efficient sputtering deposition to improve utility in industrial applications. Summary of the invention

[0005] According to a first aspect of the present invention, there is provided an apparatus for sputtering a target material onto a substrate, the apparatus comprising:

[0006] a substrate guide arranged to guide a substrate along a curved path;

[0007] a target portion spaced apart from the substrate guide and arranged to support a target material, the target portion and the substrate guide defining a deposition zone therebetween; and

[0008] A confinement device comprising one or more magnetic elements arranged to provide a confining magnetic field to confine a plasma in a deposition zone, thereby providing, in use, sputter deposition of a target material onto a web of a substrate, the confining magnetic field being characterised in that the magnetic field lines are arranged to substantially follow a curve of a curved path, at least in the deposition zone, thereby confining the plasma around the curve of the curved path.

[0009] By guiding the substrate along a tortuous path, the apparatus provides compact sputtering deposition of target material over a large surface area of ​​the substrate, for example in a "roll-to-roll" type system. A roll-to-roll deposition system may be more efficient than batch processing, which may involve stopping deposition between batches.

[0010] Since the magnetic field lines substantially follow the curve of the curved path, the plasma can be confined to enter the deposition zone around the curved path. Therefore, the density of the plasma is more uniform in the deposition zone, at least in the direction around the curve of the curved path. This can increase the uniformity of the target material deposited on the substrate. Therefore, the consistency of the processed substrate can be improved, reducing the need for quality control.

[0011] In an example, one or more magnetic elements are arranged to provide a confining magnetic field, thereby confining the plasma into the form of a curved sheet. By confining the plasma into the form of a curved sheet, the area of ​​the substrate exposed to the plasma can be increased. Therefore, sputtering deposition can be performed on a larger surface area of ​​the substrate, which can improve the efficiency of sputtering deposition. By providing a curved plasma sheet, the density of the plasma can be more uniform. The uniformity of the plasma can be increased around the curve of the curved path and over the width of the substrate. This can allow the target material to be more uniformly sputtered and deposited onto the substrate.

[0012] In an example, one or more magnetic elements are arranged to provide a confining magnetic field to confine the plasma in the form of a curved sheet having a substantially uniform density at least in the deposition region. With a substantially uniform plasma density in the deposition region, the target material can be deposited on the substrate with a substantially uniform thickness. This can improve the consistency of the substrate after deposition and reduce the need for quality control.

[0013] In an example, one or more magnetic elements are electromagnets. The use of electromagnets allows the strength of the confining magnetic field to be controlled. For example, the device may include a controller arranged to control the magnetic field provided by the one or more electromagnets. In this way, the density of the plasma in the deposition zone may be adjusted, which may be used to adjust the deposition of the target material on the substrate. Thus, the control of the sputtering deposition may be improved, increasing the flexibility of the device.

[0014] In an example, one or more magnetic elements are in the form of a solenoid which, in use, is elongated in a direction substantially perpendicular to the magnetic field lines generated within it. With this arrangement, the plasma can be confined by the elongated solenoid along a longer length than would otherwise be possible, for example in the form of a sheet. This can allow an increased area of ​​the substrate and / or target material exposed to the plasma. This can improve the efficiency of sputter deposition and can alternatively or additionally provide a more uniform deposition of the target material on the substrate.

[0015] In examples, the confinement device includes at least two magnetic elements arranged to provide a confining magnetic field. This can allow for more precise confinement of the plasma, and / or can allow for greater freedom in controlling the confining magnetic field. For example, having at least two magnetic elements can increase the substrate area exposed to the plasma, and therefore increase the substrate area on which the target material is deposited. This can increase the efficiency of the sputtering deposition process. In these examples, at least two magnetic elements can be arranged so that the area of ​​relatively high magnetic field strength provided between the magnetic elements is substantially along the curve of the curved path. This can increase the uniformity of the plasma around the curve of the curved path, which in turn can increase the uniformity of the target material sputter-deposited on the substrate.

[0016] In an example, the magnetic field lines characterizing the confining magnetic field are each curved so as to substantially follow the curve of the curved path at least in the deposition zone. The magnetic field lines substantially following the curve of the curved path can confine the plasma around the curve of the curved path because the plasma may tend to follow the magnetic field lines. This can provide a more uniform plasma distribution at least around the curve of the curved path. This can provide a more uniform sputtering deposition of the target material on the substrate at least in the direction around the curve of the curved path. In these examples, one or more magnetic elements may include a solenoid having an opening through which the plasma is confined in use, and the opening is elongated in a direction substantially parallel to the longitudinal axis of the substrate guide. Confining the plasma through the opening of the solenoid can increase the plasma density in the deposition zone. For example, a certain amount of plasma can be compressed or otherwise contracted to pass through the opening of the solenoid. With this arrangement, the plasma can be confined to a wider area than otherwise, such as corresponding to the elongated opening of the solenoid. For example, the plasma can be confined by the elongated opening of the solenoid in the form of a sheet. The plasma may be more uniform than otherwise. Additionally or alternatively, because the plasma is confined by the elongated openings in the surface, a larger surface area of ​​the substrate and / or target material can be exposed to the plasma than would otherwise be the case. This can improve the efficiency of the sputtering deposition process. In these examples, the apparatus can include a plasma generating device arranged to generate the plasma, wherein the plasma generating device includes one or more elongated antennas extending in a direction substantially parallel to the longitudinal axis of the substrate guide. With this arrangement, the plasma can be generated along the length of the one or more elongated antennas, which can allow the area of ​​the substrate and / or target material to be exposed to the plasma to be increased. This can improve the efficiency of the sputtering deposition and can alternatively or additionally provide a more uniform deposition of the target material on the substrate.

[0017] In an example, the magnetic field lines characterizing the confining magnetic field are arranged so that an imaginary line extending perpendicular to each magnetic field line and connecting the magnetic field lines is curved, thereby substantially following the curve of the curved path at least in the deposition zone. With this arrangement of magnetic field lines, the plasma can take the form of a curved sheet that extends through a deposition zone of a greater width than otherwise, but bends around the curved path along which the substrate is guided. This can increase the exposure of the substrate and / or target material to the plasma, which can increase the efficiency of sputtering and depositing the target material on the substrate. Since the imaginary line is bent into a curve substantially along the curved path at least in the deposition zone, the plasma will be more uniform around the curve of the curved path. This can improve the uniformity of the target material sputtered and deposited on the substrate. In these examples, one or more magnetic elements may include a solenoid having an opening through which the plasma is confined in use, the opening being curved and elongated in a direction substantially perpendicular to the longitudinal axis of the substrate guide. The curved elongated opening of the solenoid can improve the confinement of the plasma in the form of a curved sheet. Due to the confinement of the plasma by the opening of the solenoid, the plasma density in the deposition zone can be increased. The plasma can be more evenly confined along the length of the solenoid and have a more even distribution around the curve of the curved path. This can improve the uniformity of the target material sputter-deposited on the substrate. In these examples, the apparatus can also include a plasma generating device arranged to generate the plasma, wherein the plasma generating device includes one or more elongated antennas that are curved and extend in a direction substantially perpendicular to the longitudinal axis of the substrate guide. The elongated antenna can be used to generate an elongated, curved plasma sheet along the length of the elongated antenna. This can allow the area of ​​the substrate and / or target material to be exposed to the plasma to be increased. This can improve the efficiency of the sputtering deposition and can alternatively or additionally provide a more uniform deposition of the target material on the substrate.

[0018] In an example, the target portion is arranged or configurable to be arranged such that at least a portion of the target portion defines a support surface that forms an obtuse angle relative to a support surface of another portion of the target portion. This may allow an increase in the area over which sputtering deposition may be achieved without increasing the spatial footprint of the target portion and without changing the tortuous path. This may improve the efficiency of the sputtering deposition.

[0019] In an example, the target portion is substantially curved. This can increase the surface area of ​​the target portion exposed to the substrate within the deposition region, which can increase the efficiency with which sputtering deposition can be achieved and can be more compact than other arrangements.

[0020] In an example, the target portion is arranged substantially along or close to the curve of the curved path. This can improve the uniformity of sputtering and depositing the target material of the target portion on the substrate along the curve of the curved path. This can reduce the need for quality control.

[0021] In an example, the substrate guide is provided by a curved member that guides the web of substrate along a curved path. The web of substrate may be guided by rotation of the curved member, which may be a roller or drum. In this way, the apparatus may form part of a "roll-to-roll" processing apparatus that may process substrates more efficiently than a batch processing apparatus.

[0022] According to a second aspect of the invention, there is provided a method of sputter depositing a target material onto a substrate, the substrate being guided along a curved path by a substrate guide, wherein a deposition zone is defined between the substrate guide and a target portion supporting the target material, the method comprising:

[0023] A magnetic field is provided to confine the plasma in the deposition zone to sputter deposit the target material onto the web of substrate, the magnetic field being characterized in that the magnetic field lines are arranged to curve substantially along the tortuous path at least in the deposition zone to confine the plasma around the tortuous path.

[0024] This approach can improve the uniformity of the plasma around the curve of the tortuous path, which in turn can improve the uniformity of the target material deposited on the substrate web. By using a tortuous path, the method can be implemented as a roll-to-roll type process, which can be performed more efficiently than batch processing.

[0025] According to a third aspect of the present invention, there is provided a device, comprising:

[0026] a plasma processing zone; and

[0027] A confinement device comprising one or more magnetic elements arranged to provide a confining magnetic field to confine a plasma in a plasma processing region, thereby providing plasma processing in use, the confinement magnetic field being characterized in that magnetic field lines are arranged to substantially follow a curved path at least in the plasma processing region, thereby confining the plasma around the curve of the curved path.

[0028] The apparatus can increase the uniformity of the plasma around the curve of the tortuous path. Thus, the output of the plasma process provided by the plasma can be more consistent than otherwise.

[0029] Further features will become apparent from the following description which is given by way of example only with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram showing a cross section of a device according to an example;

[0031] Figure 2 It is shown Figure 1 a schematic diagram of a cross-section of an example device of FIG. 1 , but including schematic magnetic field lines;

[0032] Figure 3 It is shown Figure 1 and 2 a schematic diagram of a plan view of a portion of an example device;

[0033] Figure 4 It is shown Figure 3 A schematic diagram of a plan view of a portion of an example device, but including schematic magnetic field lines;

[0034] Figure 5 is a schematic diagram showing a cross section of a magnetic element according to an example;

[0035] Figure 6 is a schematic diagram showing a cross section of a device according to an example;

[0036] Figure 7 is a schematic diagram showing a cross section of a device according to an example;

[0037] Figure 8 is a schematic diagram showing a perspective view of a device according to an example; and

[0038] Fig. 9 is a schematic flow chart illustrating a method according to an example. DETAILED DESCRIPTION

[0039] Details of the apparatus and methods according to the examples will become apparent from the following description with reference to the accompanying drawings. In this specification, many specific details of certain examples are set forth for the purpose of explanation. References to "examples" or similar language in the specification mean that a particular feature, structure, or characteristic described in conjunction with the example is included in at least one example, but not necessarily in other examples. It should also be noted that certain examples are schematically described, and certain features are omitted and / or necessarily simplified in order to facilitate explanation and understanding of the concepts behind the examples.

[0040] refer to Figures 1 to 5 , an example apparatus 100 for sputter depositing a target material 108 onto a substrate 116 is shown.

[0041] The apparatus 100 can be used for plasma-based sputtering deposition for a large number of industrial applications, such as for thin film deposition applications, such as for the production of optical coatings, magnetic recording media, electronic semiconductor devices, LEDs, energy generating devices such as thin film solar cells, and energy storage devices such as thin film batteries. Thus, while the context of the present disclosure may in some cases relate to the production of energy storage devices or portions thereof, it will be understood that the apparatus 100 and methods described herein are not limited to the production thereof.

[0042] Although not shown in the figures for the sake of clarity, it should be understood that the apparatus 100 may be disposed within a housing (not shown) which, during use, may be evacuated to a low pressure suitable for sputtering deposition, such as 3×10 -3 For example, the housing (not shown) may be evacuated to a suitable pressure (e.g., less than 1×10 -5 Torr), and in use, a process gas or sputtering gas, such as argon or nitrogen, may be introduced into a housing (not shown) using a gas supply system (not shown) to achieve a pressure suitable for sputtering deposition (e.g., 3×10 -3 The degree of support).

[0043] Back to Figures 1 to 5 In the illustrated example, in general terms, the apparatus 100 includes a substrate guide 118 , a target portion 106 , and a magnetic confinement device 104 .

[0044] The substrate guide 118 is arranged to guide the web of substrate 116 along a curved path (the curved path is Figure 1 and 2 Indicated by arrow C).

[0045] In some examples, the base guide 118 may be provided by a flexure 118. The flexure 118 may be arranged to rotate about an axis 120, for example provided by a shaft 120. Figure 3 In the example shown, axis 120 may also be the longitudinal axis of curved member 118. In some examples, such as Figure 3 As shown, the curved member 118 can be provided by a substantially cylindrical drum or roller 118 of an overall web supply assembly 119. The web supply assembly 119 can be arranged to supply a web of substrate 116 onto and from the roller 118 such that the web of substrate 116 is carried by at least a portion of the curved surface of the roller 118. In some examples, the web supply assembly includes a first roller 110a arranged to supply the web of substrate 116 onto the drum 118 and a second roller 110b arranged to supply the web of substrate 116 from the drum 118 after the web of substrate 116 has been along the curved path C. The web supply assembly 119 can be part of a "roll-to-roll" processing apparatus (not shown) in which the web of substrate 116 is supplied from a first roll or spool (not shown) of substrate web 116, passes through the apparatus 100, and is then supplied onto a second roll or spool (not shown) to form a loaded roll (not shown) of processed substrate web.

[0046] In some examples, the substrate 116 web can be or include silicon or a polymer. In some examples, such as for the production of energy storage devices, the substrate 116 web can be or include nickel foil, but it should be understood that any suitable metal can be used instead of nickel, such as aluminum, copper, or steel, or metallized materials including metallized plastics, such as aluminum on polyethylene terephthalate (PET).

[0047] The target portion 106 is arranged to support a target material 108 .

[0048] In some examples, target portion 106 may include a plate or other support structure that supports or holds target material 108 in place during sputter deposition. Target material 108 may be a material upon which sputter deposition is to be performed on substrate 116. For example, target material 108 may be or include a material to be deposited onto a web of substrate 116 by sputter deposition.

[0049] In some examples, such as for the production of an energy storage device, the target material 108 can be or include a cathode layer of the energy storage device, or can be or include a precursor material therefor, such as a material suitable for storing lithium ions, such as lithium cobalt oxide, lithium iron phosphate, or an alkali metal polysulfide salt. Additionally or alternatively, the target material 108 can be or include an anode layer of the energy storage device, or can be or include a precursor material therefor, such as lithium metal, graphite, silicon, or indium tin oxide. Additionally or alternatively, the target material 108 can be or include an electrolyte layer of the energy storage device, or can be or include a precursor material therefor, such as a material that is ionically conductive but also an electrical insulator, such as lithium phosphorus oxynitride (LiPON). For example, the target material 108 can be or include LiPO as a precursor material for depositing LiPON onto the substrate 116, such as by reacting with nitrogen in a region of the target material 108.

[0050] Target portion 106 and substrate portion 118 are spaced apart from one another and define therebetween deposition zone 114. Deposition zone 114 may be considered the region or volume between substrate portion 118 and target portion 106 where, in use, sputter deposition of target material 108 onto the substrate 116 web occurs.

[0051] In some examples, such as those illustrated, the apparatus can include a plasma generation device 102. The plasma generation device 102 is arranged to generate a plasma 112.

[0052] In some examples, the plasma generation device 102 can include one or more antennas 102a, 102b, through which appropriate RF power can be driven by an RF power system (not shown) to generate an inductively coupled plasma 112 from a process or sputtering gas in a housing (not shown). In some examples, the plasma 112 can be generated by driving an RF current through the one or more antennas 102a, 102b, for example, at a frequency between 1 MHz and 1 GHz; a frequency between 1 MHz and 100 MHz; a frequency between 10 MHz and 40 MHz; or a frequency of about 13.56 MHz or multiples thereof. The RF power causes ionization of the process or sputtering gas to generate the plasma 112.

[0053] In some examples, the plasma generation device 102 can be disposed away from the substrate guide 118. For example, the plasma generation device 102a can be disposed at a distance radially away from the substrate guide 118. In this way, the plasma 112 can be generated away from the substrate guide 118 and away from the deposition region 114.

[0054] In some examples, one or more antennas 102a, 102b may each be an elongated antenna and extend in a direction substantially parallel to a longitudinal axis 120 of the substrate guide 108 (e.g., an axis 120 of the roller 108 passing through the origin of the radius of curvature of the curved roller 108). Figure 1 In the example of FIG. 1 , the longitudinal axis 120 of the drum 118 is also the rotation axis of the drum 118 .

[0055] In some examples, the plasma generation device 102 includes two antennas 102a, 102b for generating the inductively coupled plasma 112. In some examples (e.g., Figure 31 (shown in FIG. 1 ), the antennas 102a, 102b are elongated and substantially linear and extend parallel to a longitudinal axis 120 (which may also be the axis of rotation 120 of the flexure 118). The antennas 102a, 102b may extend substantially parallel to each other and may be arranged transversely to each other. This may allow an elongated region of plasma 112 to be precisely generated between the two antennas 102a, 102b, which in turn may help to precisely confine the generated plasma 112 within the deposition region 114, as described in more detail below. In some examples, the antennas 120a, 120b may be similar in length to the substrate guide 118, and therefore similar to the width of the substrate 116 web carried by the substrate guide 118. The elongated antennas 102a, 102b may provide a plasma 112 that is generated over an area whose length corresponds to the length of the substrate guide 118 (and therefore the width of the substrate 116 web), and therefore may allow the plasma 112 to be uniformly or consistently available across the width of the substrate 116 web. As described in more detail below, this in turn can help provide uniform or consistent sputtering deposition.

[0056] The confinement device 104 includes one or more magnetic elements 104a, 104b. The magnetic elements 104a, 104b are arranged to provide a confinement magnetic field to confine a plasma 112 (e.g., a plasma generated by the plasma generation device 102) in a deposition region 114, so as to provide sputtering deposition of a target material 108 onto a web of a substrate 116 in use. The confinement magnetic field is characterized in that the magnetic field lines substantially follow the curve of the curved path C at least in the deposition region 114, thereby confining the plasma 112 around the curved path C.

[0057] It will be appreciated that magnetic field lines may be used to characterize or describe the arrangement or geometry of a magnetic field. Thus, it will be appreciated that the confining magnetic field provided by the magnetic elements 104a, 104b may be described or characterized by magnetic field lines arranged to follow a curve of the curved path C. It will also be appreciated that, in principle, the entire or total magnetic field provided by the magnetic elements 103a, 104b may include portions characterized by magnetic field lines that are not arranged to follow a curve of the curved path C. However, the confining magnetic field provided, i.e., a portion of the entire or total magnetic field provided by the magnetic elements 104a, 104b that confines the plasma to the deposition region 114, is characterized by magnetic field lines that follow a curve of the curved path C.

[0058] The curve of the curved path C may be understood as the degree to which the path along which the substrate guide 118 carries the substrate web is curved. For example, the substrate guide 118 may include a curved member 118, such as a roller 118, that carries the substrate 116 along the curved path C. In such an example, the curve of the curved path C may be generated by the degree to which the curved surface of the curved member 118 that carries the substrate 116 web is curved, i.e., offset from a flat plane. In other words, the curve of the curved path C may be understood as the degree to which the curved member 118 bends the curved path C along which the substrate 116 web is curved. A curve substantially along the curved path C may be understood as substantially conforming to or replicating the curved shape of the curved path C. For example, the magnetic field lines may follow a curved path that has a common center of curvature with the curved path C, but has a different radius of curvature, which is greater than the curved path C in the example shown. For example, the magnetic field lines may follow a curved path that is substantially parallel to the curved path C of the substrate 116 but radially offset. In an example where the flexure or roller 118 guides the substrate 116 on a curved path C, the magnetic field lines may follow a curved path that is substantially parallel to but radially offset from the curved surface of the flexure or roller 118. For example, at least in the deposition zone 114, the magnetic field lines may be characterized by Figure 2 The magnetic field lines of the confining magnetic field in follow a curved path that is substantially parallel to the curved path C but radially offset so that it substantially follows the curve of the curved path C.

[0059] The magnetic field lines characterizing the confining magnetic field may be arranged to curve along the curved path C around most or a significant portion of the curved path C, for example, over all or most of an imaginary portion of the curved path C where the substrate 116 is guided by the substrate guide 118. For example, the curved path C may represent a portion of the circumference of an imaginary circle, and the magnetic field lines characterizing the confining magnetic field may be arranged to curve along the curved path C around at least about 1 / 16, or at least about 1 / 8, or at least about 1 / 4, or at least about 1 / 2 of the circumference of the imaginary circle.

[0060] In examples where the substrate guide 118 is provided by a flexure or roller 118, the magnetic field lines representing the confining magnetic field may be arranged along the curve of the flexure or roller 118 around a substantial or significant portion of the flexure 118, such as over all or a substantial portion of an imaginary portion of the flexure 118 that carries or contacts the web of substrate 116 in use. For example, the flexure 118 may be substantially cylindrical in shape, and the magnetic field lines representing the confining magnetic field may be arranged along the curve of the flexure 118 around at least about 1 / 16, or at least about 1 / 8, or at least about 1 / 4, or at least about 1 / 2 of the circumference of the flexure 118. For example, in Figure 2 The magnetic field lines representing the confining magnetic field follow a curved path around at least 1 / 4 of the circumference of the curved member 118 .

[0061] The example magnetic field provided by the example magnetic elements 103a, 104b is Figure 2 and 4 Schematically shown in FIG, where magnetic field lines (conventionally represented by arrow lines) are used to characterize or describe the magnetic field provided in use. As described above, some magnetic field lines do not substantially follow the curvature of the curved member, but the confining magnetic field (i.e., the magnetic field that confines the plasma to the deposition region) is characterized by magnetic field lines arranged along the curve of the curved path C. Figure 2 and Figure 4 As best shown in , the magnetic field lines characterizing the confining magnetic field can each be curved so as to substantially follow the curve of the curved path C at least in the deposition zone 114.

[0062] The magnetic field lines are arranged along the curve of the curved path C of the substrate 116, and the plasma 112 generated around the curve of the curved path C is confined to the deposition area 114. This is because the generated plasma 112 tends to be along the magnetic field lines. For example, the plasma ions in the confined magnetic field and with a certain initial velocity will be subject to the Lorentz force, which causes the ions to move periodically around the magnetic field lines. If the initial motion is not strictly perpendicular to the magnetic field, the ions will move along the spiral path centered on the magnetic field lines. Therefore, the plasma containing such ions tends to be along the magnetic field lines, and is therefore confined to the path thus defined. Therefore, since the magnetic field lines are arranged substantially along the curve of the curved path C, the plasma 112 will be confined to be substantially along the curve of the curved path C, and is therefore confined to enter the deposition area 114 around the curve of the curved path C.

[0063] Confining the generated plasma 112 so as to substantially follow the curve of the curved path C can allow for a more uniform plasma density distribution at the substrate 116 web, at least in a direction around the curve of the curved path C. This in turn can allow for a more uniform sputter deposition on the substrate 116 web in a direction around the curved path C. Thus, the sputter deposition can in turn be performed more consistently. This can, for example, improve the consistency of the processed substrates and can, for example, reduce the need for quality control. This can be compared to, for example, a magnetron-type sputter deposition apparatus, in which the magnetic field lines characterizing the magnetic field generated thereby tightly loop in and out of the substrate, thus not allowing for a uniform distribution of plasma density to be provided at the substrate.

[0064] Alternatively or additionally, confining the generated plasma 112 so as to substantially follow the curve of the tortuous path C can allow an increased area of ​​the substrate 116 to be exposed to the plasma 112, and thus an increased area over which sputter deposition can be achieved. For example, for a given degree of deposition, this can allow the substrate 116 web to be passed through a roll-to-roll apparatus at a faster rate, thereby achieving more efficient sputter deposition.

[0065] In some examples, the magnetic confinement device 104 may include at least two of the magnetic elements 104a, 104b arranged to provide a magnetic field. For example, the at least two magnetic elements 104a, 104b may be arranged such that a region of relatively high magnetic field strength provided between the magnetic elements 104a, 104b is substantially along the curve of the curved path C. Figure 1 and 2 In the example schematically shown, two magnetic elements 104a, 104b are located on opposite sides of the drum 118, and each is arranged above the lowest part of the drum 118 (at Figure 1 104a, 104b confines the plasma 112 along a curve of the curved path C on both sides of the drum 118, e.g., an infeed side where a web of substrate 116 is fed onto the drum 118, and an outfeed side where a web of substrate 116 is fed out of the drum 118. Thus, having at least two magnetic elements may (further) increase the area of ​​the substrate 116 exposed to the plasma, thereby increasing the area over which sputter deposition may be achieved. For example, for a given degree of deposition, this may allow a web of substrate 116 to be fed through a roll-to-roll apparatus at a (still) faster rate, and thus for more efficient sputter deposition.

[0066] In some examples, one or more of the magnetic elements 104a, 104b may be electromagnets 104a, 104b. The device 100 may include a controller (not shown) arranged to control the strength of the magnetic field provided by the one or more electromagnets 104a, 104b. This may allow control of the arrangement of magnetic field lines characterizing the limiting magnetic field. This may allow adjustment of the plasma density at the substrate 116 and / or the target material 108, thereby improving control of the sputtering deposition. This may increase the flexibility of the operation of the device 100.

[0067] In some examples, one or more magnetic elements 104a, 104b may be provided by solenoids 104a, 104b. Each solenoid 104a, 104b may define an opening through which the plasma 112 passes (is confined) in use. Figure 1 and 2 In the example schematically shown in FIG. 1 , there may be two solenoids 104a, 104b, and each solenoid 104a, 104b may be angled such that the region of relatively high magnetic field strength provided between the solenoids 104a, 104b substantially follows the curve of the curved path C. Thus, as Figure 1 As shown, the generated plasma 112 can pass through the first solenoid 104a, below the roller 118 (at Figure 1 ) into the deposition zone 114 and upward toward and through the second solenoid 104b. Figure 1 and 2Only two magnetic elements 104a, 104b are shown in the figure, but it will be appreciated that additional magnetic elements (not shown), such as additional solenoids (not shown), may be placed along the curved path of the plasma 112. This may allow for an enhancement of the confining magnetic field, and thus fine confinement, and / or may allow for more degrees of freedom in the control of the confining magnetic field.

[0068] In some examples, one or more magnetic elements 104a, 104b are arranged to provide a magnetic field to confine the plasma 112 in the form of a curved sheet. In some examples, one or more magnetic elements 104a, 104b are arranged to provide a magnetic field to confine the plasma 112 in the form of a curved sheet having a substantially uniform density at least in the deposition region 114.

[0069] For example, Figure 4 and 5 As shown, in some examples, one or more of the solenoids 104a, 104b may be elongated in a direction substantially perpendicular to the magnetic field lines generated therein during use. Figures 3 to 5 As best shown, the solenoids 104a, 104b may each have an opening through which the plasma 112 is confined in use (through which the plasma 112 passes in use), wherein the opening is elongated in a direction substantially parallel to the longitudinal axis 120 of the flexure 118. Figure 3 and Figure 4 As best seen in FIG. 1 , the elongated antennas 102a, 102b can extend parallel to and in line with the solenoids 104a, 104b. As described above, the plasma 112 can be generated along the length of the elongated antennas 102a, 102b, and the elongated solenoid 104a can confine the plasma 112 in a direction away from the elongated antennas 102a, 102b and through the elongated solenoid 104a.

[0070] The plasma 112 may be confined from the elongated antennas 102a, 102b by the elongated solenoid 104a in the form of a sheet. That is, in the form of a depth (or thickness) of the plasma 112 that is significantly less than its length or width. The thickness of the plasma 112 sheet may be substantially constant along the length and width of the sheet. The density of the plasma 112 sheet may be substantially uniform in one or both of its width and length directions. The plasma 112 in the form of a sheet may be confined by the magnetic field provided by the solenoids 104a, 104b around the curved member 118 so as to enter the deposition region 114 along the curve of the curved path C. Therefore, the plasma 112 may be confined in the form of a curved sheet. The thickness of the curved sheet of the plasma 112 may be substantially constant along the length and width of the curved sheet. The plasma 112 in the form of a curved sheet may have a substantially uniform density, for example, the density of the plasma 112 in the form of a curved sheet may be substantially uniform in one or both of its length and width.

[0071] Confining the plasma to the form of a curved sheet may allow an increased area of ​​the substrate 116 carried by the curved member 118 to be exposed to the plasma 112, and therefore an increased area over which sputter deposition may be achieved. For example, for a given degree of deposition, this may allow a web of substrate 116 to be fed through a roll-to-roll apparatus at a (still) faster rate, and therefore for more efficient sputter deposition.

[0072] Confining the plasma 112 to the form of a curved sheet, such as a curved sheet having a substantially uniform density at least in the deposition zone 114, can alternatively or additionally allow a more uniform distribution of the plasma density at the substrate 116 web, such as in a direction around the bend of the curved member 118 and over the length of the curved member 118. This in turn can allow for more uniform sputter deposition on the substrate 116 web, such as in a direction around the curved member surface and over the width of the substrate 116. Thus, the sputter deposition can be performed more consistently. This can, for example, improve the consistency of the processed substrates and can, for example, reduce the need for quality control. This can be compared to, for example, a magnetron-type sputter deposition apparatus, in which the magnetic field lines characterizing the magnetic field generated thereby tightly loop in and out of the substrate, thereby not allowing a uniform distribution of the plasma density to be provided on the substrate.

[0073] In some examples, the confined plasma 112 may be a high density plasma at least in the deposition region 114. For example, the confined plasma 112 (in the form of a curved sheet or otherwise) may have a density of, for example, 10 11 cm -3 The high density plasma 112 in the deposition region 114 may allow for efficient and / or high rate sputtering deposition.

[0074] exist Figures 1 to 5 In the example shown, the target portion 106 and the target material 108 supported thereby are substantially planar. However, in some examples (as described in more detail below), the target portion can be arranged, or can be configured to be arranged, such that at least a portion of the target portion defines a support surface that forms an obtuse angle relative to a support surface of another portion of the target portion. For example, the target portion can be substantially curved. For example, the target portion can be arranged to substantially follow a curve of a curved path C.

[0075] Figure 6 An example device 600 is shown. Many of the illustrated components of the device 600 are similar to Figures 1 to 5 The components of the device 100 shown and described above are the same and will not be described again. Like features are given like reference numerals, and it will be understood that reference to Figures 1 to 5 Any features of the described examples may be applied to Figure 6 However, in Figure 6 In the example shown, the target portion 606 is substantially curved. Figure 6 In the example of , the target material 608 supported by the target portion 606 is correspondingly substantially curved. In this case, any portion of the curved target portion 606 forms an obtuse angle along the curvilinear direction with any other portion of the curved target portion 606. In some examples, different portions of the target portion 606 can support different target materials, for example, to provide a desired deposition arrangement or composition to the substrate 116 web.

[0076] In some examples, the curved target portion 606 may substantially follow the curve of the curved path C. For example, the curved target portion 606 may substantially conform to or replicate the curved shape of the curved path C. For example, the curved target portion 606 may have a curve that is substantially parallel to the curved path but radially offset therefrom. For example, the curved target portion 606 may have a curve that has a common center of curvature with the curved path C, but has a different radius of curvature than the curved path C, and in the example shown, the radius of curvature is larger. Thus, the curved target portion 606 may in turn substantially follow the curve of the curved plasma 112 that is confined around the curved member 118 in use. In other words, in some examples, the plasma 112 may be confined by the magnetic elements 104a, 104b of the confinement device to be located between the path C of the substrate 116 and the target portion 606, and substantially along the curved path C and the curve of the curved target portion 606.

[0077] As for Figures 1 to 5 The target portion 108 of the device 100 is shown, and it should be understood that Figure 6The target portion 606 (and the target material 608 supported thereby) can extend substantially across the entire length of the flexure 118 (e.g., in a direction parallel to the longitudinal axis 120 of the roller 118). This can allow for maximizing the surface area of ​​the substrate 116 web carried by the roller 118 onto which the target material 608 can be deposited.

[0078] As described above, the plasma 112 may be confined to substantially follow the curve of the curved path C and the curved target portion 606. The area or volume between the curved path C and the curved target portion 606 may be correspondingly curved around the curved member 118. Thus, the deposition zone 614 may represent a curved volume in which, in use, sputter deposition of the target material 608 onto the substrate 116 carried by the curved member 118 occurs. This may allow the surface area of ​​the web of substrate 116 carried by the curved member 118 present in the deposition zone 614 to be increased at any one time. This in turn may allow an increase in the surface area of ​​the web of substrate 116 onto which the target material 608 may be deposited in use. This in turn may allow an increase in the area over which sputter deposition may be achieved, but without significantly increasing the spatial footprint of the target portion 606, and without changing the size of the curved member 118. For example, for a given degree of deposition, this may allow the web of substrate 116 to be fed through a roll-to-roll apparatus at a (still) faster rate, thereby more efficiently sputtering deposits, and in a spatially efficient manner.

[0079] Figure 7 An example device 600 is shown. Many of the illustrated components of device 700 are similar to Figures 1 to 5 The components of the device 100 shown and described above are the same and will not be described again. Like features are given like reference numerals, and it will be understood that reference to Figures 1 to 6 Any features of the described examples may be applied to Figure 7 However, in Figure 7 In the example shown, the target portion 706 is arranged or configurable such that at least a portion 706 a of the target portion 706 defines a surface that forms an obtuse angle relative to a surface of another portion 708 b of the target portion 706 .

[0080] In some examples, the angle formed by the first portion 706a of the target portion 706 and the second portion 706b (e.g., adjacent portions) of the target portion 708 may be fixed to an obtuse angle. The obtuse angle may be selected so that the first portion 706a and the second portion 706b are arranged together to form a curve close to the curved path C. Figure 7 As shown in the example of Figure 714. The deposition zone 714 is a substantially planar) portion 706a, 706b, 706c, each portion being at an obtuse angle relative to an adjacent portion. The first portion 706a may be disposed toward the feed side of the curved path C, the second portion 706b may be disposed toward the central portion of the curved path C, and the third portion 706c may be disposed toward the give side of the curved path C. The three portions 706a, 706b, 706c may be arranged together to approximate the curve of the curved path C. The deposition zone 714 may thus approximate a curved volume where sputter deposition of target material 708a, 708b, 708c onto the substrate 116 occurs in use. Thus, at any one time, the increase in the surface area of ​​the web of substrate 116 present in the deposition zone 714 may be increased. For example, this may allow an increase in the area over which sputter deposition may be performed, but without substantially increasing the spatial footprint of the target portion 706, and without changing the size of the curved member 118.

[0081] In some examples, the target portion 706 may be configured to be arranged so that at least a portion 706a of the target portion 706 defines a surface that forms an obtuse angle relative to a surface of another portion 708b of the target portion 706. For example, the angle formed by the first portion 706a of the target portion 706 and the second portion (e.g., an adjacent portion) 706b of the target portion 706 may be configurable. For example, the first portion 706a and the second portion 706b may be mechanically connected by a hinge element 724 or other such components that allow the angle between the first portion 706 and the second portion 706b to be changed. Similarly, the second portion 706b and the third portion 706c may be mechanically connected by a hinge element 726 or other such components that allow the angle between the second portion 706b and the third portion 706c to be changed. An actuator and a suitable controller (not shown) may be provided to move the first portion 706a and / or the third portion 706c relative to the second portion 706b, i.e., to change the angle between the first portion 706a and / or the third portion 706c relative to the second portion 706b. This may allow control of the plasma density experienced by the target material 708a, 708c of the first portion 706a or the third portion 706c of the target portion, and may therefore allow control of the deposition rate in use.

[0082] Alternatively or in addition, the confining magnetic field provided by the magnetic elements 104a, 104b may be controlled by a controller (not shown) to vary the curvature of the plasma 112, thereby controlling the plasma density experienced by the target material 708a, 708b, 708c of the first portion 706a, the second portion 706b, or the third portion 706c of the target portion, thereby allowing control of the deposition rate in use.

[0083] In some examples, the target material provided on one portion 706a, 706b, 706c of the target portion 700 may be different from the target material provided on another portion 706a, 706b, 706c of the target portion. This may allow a desired arrangement or composition of target materials to be sputter deposited onto the substrate 116 web. Control of the plasma density experienced by one or more target portions 706a, 706b, 706c, such as by controlling the angle formed by the first portion 706a or the third portion 706c with the second portion 706b, and / or by controlling the curvature of the confined plasma by controlling the magnetic elements 104a, 104b, may allow control of the type or composition of target material sputter deposited onto the substrate 116 web. This may allow for flexible sputter deposition.

[0084] exist Figures 1 to 7 In the example shown, the magnetic field lines characterizing the confining magnetic field are each curved so as to substantially follow the curve of the curved path C at least in the deposition zone 114. However, this is not necessarily the case, and in other examples, other arrangements may be used in which the confining magnetic field is characterized in that the magnetic field lines are arranged to substantially follow the curve of the curved path C at least in the deposition zone 114 so as to confine the plasma 112 around the curve of the curved path C.

[0085] For example, in some examples, the magnetic field lines representing the confining magnetic field may be arranged such that an imaginary line extending perpendicular to each magnetic field line and connecting the magnetic field lines is curved, thereby substantially following the curve of the curved path C at least in the deposition zone.

[0086] For example, Figure 8 An example device 800 is shown. Many of the illustrated components of the device 800 may be used with Figures 1 to 7 The components of the device 100 shown and described above are the same and will not be described again. Like features are given like reference numerals, and it should be understood that reference to Figures 1 to 7 Any features of the described examples may be applied to Figure 8 However, in Figure 8 In the example shown, the magnetic element 804a of the magnetic confinement device 804 is arranged to provide a confinement magnetic field, wherein the magnetic field lines ( Figure 8 The black arrows in FIG. 8 are themselves substantially straight, but are arranged so that an imaginary line 806 extending perpendicular to each magnetic field line and connecting the magnetic field lines is curved so that at least in the deposition region (for clarity, in FIG. Figure 8 ) is substantially along a curve of the curved path C.

[0087] The plasma generating device 802 may include one or more elongated antennas 802a that are curved and extend in a direction substantially perpendicular to the longitudinal axis 120 of the curved member or drum 118. Figure 8In the example of FIG. 1 , the longitudinal axis 120 of the flexure 118 is also the axis of rotation of the flexure 118. For clarity, Figure 8 Only one antenna 802a is shown in the figure, but it should be understood that more than one such antenna 802a may be used. The curved antenna 802a may substantially follow the curve of the curved path C. For example, the curved antenna 802a may be parallel to the curved path C but radially and axially offset from the curved path C, such as parallel to the curved surface of the curved member 118 that guides the substrate along the curved path C but radially and axially offset from the curved path C. The curved antenna 802a may be driven with RF power to generate a plasma having a substantially curved shape (for clarity, Figure 8 not shown).

[0088] The magnetic element 804a may include a solenoid 804a. For clarity, Figure 8 Only one magnetic element 804a is shown, but it should be understood that, for example, Figure 8 In the sense that another such magnetic element (not shown) may be placed on the side of the flexure 118 opposite the solenoid 804a. The solenoid 804a may have an opening that, in use, causes the plasma ( Figure 8 118) is confined by the opening. The opening can be curved and elongated in a direction substantially perpendicular to the longitudinal axis (rotation axis) 120 of the curved member 118. The curved solenoid 804a can substantially follow the curve of the curved path C. For example, the curved solenoid 804a can be parallel to the curved surface of the curved member 118 but radially and axially offset therefrom. The curved solenoid 804a can be disposed in the middle of the curved antenna 802a and the curved member 118. The curved solenoid 804a provides a confined magnetic field in which the field lines are arranged so that an imaginary line 806 extending perpendicular to each magnetic field line and connecting the magnetic field lines is bent, thereby substantially following the curve of the curved path C at least in the deposition area.

[0089] Plasma can be generated along the length of the curved antenna 802a ( Figure 8 ), and the bending solenoid 804a can be used to turn the plasma ( Figure 8804a). The plasma may be limited by the curved solenoid 804a in the form of a curved sheet. In this case, the length of the curved sheet extends in a direction parallel to the longitudinal (rotational) axis 120 of the curved member 118. The plasma in the form of a curved sheet may be limited by the magnetic field provided by the solenoid 804a around the curved member 118, thereby replicating the curve of the curved member 118. The thickness of the plasma curved sheet may be substantially constant along the length and width of the curved sheet. The plasma in the form of a curved sheet may have a substantially uniform density, for example, the density of the plasma in the form of a curved sheet may be substantially uniform over one or both of its length and width. As described above, the plasma limited to the form of a curved sheet may allow an increase in the area over which sputtering deposition may be achieved, thereby allowing more efficient sputtering deposition, and / or a more uniform plasma density distribution at the substrate 116 coil, for example, in a direction around the curve of the curved member and over the width of the substrate 116. This in turn may allow for more uniform sputter deposition on the substrate 116 web, such as in directions around the surface of the flexure and over the length of the flexure 118, which may improve consistency in substrate processing.

[0090] refer to Fig. 9 , schematically illustrates an example method for sputtering and depositing a target material 108, 608, 708a, 708b, 708c onto a web of substrate 116. In the method, the web of substrate 116 is guided by a substrate guide 118 along a curved path C. A deposition zone 114, 614, 714 is defined between the substrate guide 118 and a target portion 106, 606, 706a, 706b, 706c supporting the target material 108, 608, 708a, 708b, 708c. The target material 108, 608, 708a, 708b, 708c, the web of substrate 116, the deposition zone 114, 614, 714, the target portion 106, 606, 706a, 706b, 706c, the substrate guide 118, and / or the curved path C may be, for example, the web of substrate 116 described above with reference to FIG. Figures 1 to 8 In some examples, the method can be performed by referring to Figures 1 to 8 The invention may be performed by any one of the devices 100, 600, 700, 800 described herein.

[0091] In some examples, the method may include, at step 902, generating a plasma. For example, the plasma may be generated by Figures 1 to 8 The plasma generation device 102, 802 is described as one of the plasma generation devices 102, 802.

[0092] In step 904, the method includes providing a magnetic field to confine the plasma to the deposition zone 114, 614, 714, thereby causing the target material 108, 608, 708a, 708b, 708c to be sputter-deposited onto the substrate 116 web. The magnetic field is characterized in that the magnetic field lines are arranged to substantially follow the curve of the curved path C at least in the deposition zone 114, 614, 714, so as to confine the plasma 112 around the curve of the curved path C. For example, the plasma can be formed by the above reference Figures 1 to 8 One of the magnetic restraining devices 104, 804 is described as restraining.

[0093] As described above, confining the generated plasma 112 in this manner can allow for a more uniform distribution of plasma density at the substrate 116 web, at least in a direction around the curve of the curved path C. This in turn can allow for a more uniform sputter deposition on the substrate 116 web in a direction around the surface of the curved member 118. Thus, the sputter deposition can be performed more consistently. This can, for example, improve the consistency of the processed substrates and can, for example, reduce the need for quality control. This can be compared to, for example, magnetron-type sputter deposition, in which the magnetic field lines characterizing the magnetic field generated thereby tightly loop in and out of the substrate, thus not allowing for a uniform distribution of plasma density to be provided on the substrate.

[0094] Furthermore, confining the generated plasma 112 in this manner so as to follow a curve along a tortuous path can allow an increased area of ​​the substrate 116 to be exposed to the plasma 112, and thus an increased area over which sputter deposition can be achieved. For example, for a given degree of deposition, this can allow the substrate 116 web to be passed through a roll-to-roll apparatus at a faster rate, thereby achieving more efficient sputter deposition.

[0095] The above examples should be understood as illustrative examples of the present invention. It should be understood that any feature described with respect to any one example can be used alone or in combination with other features described, and can also be used in combination with one or more features of any other example, or in combination with any combination of any other example. In addition, equivalents and modifications not described above may also be adopted without departing from the scope of the present invention as defined by the appended claims.

Claims

1. An apparatus for sputtering a target material onto a substrate, the apparatus comprising: a substrate guide arranged to guide a substrate along a curved path; a target portion spaced apart from the substrate guide and arranged to support a target material, the target portion and the substrate guide defining a deposition zone therebetween; as well as a confinement device comprising one or more magnetic elements arranged to provide a confining magnetic field to confine the plasma in a deposition zone, thereby providing, in use, sputtering deposition of target material onto a substrate web, the confining magnetic field being characterized in that the magnetic field lines are arranged to substantially follow a curve of a curved path, at least in the deposition zone, thereby confining the plasma around said curve of the curved path, Therein, one or more magnetic elements take the form of a solenoid which, in use, is elongated in a direction substantially perpendicular to the direction of magnetic field lines generated within the solenoid.

2. The device according to claim 1, wherein: The one or more magnetic elements are arranged to provide a confining magnetic field to confine the plasma in the form of a curved sheet.

3. The device according to claim 1, wherein: The one or more magnetic elements are arranged to provide a confining magnetic field to confine the plasma in the form of a curved sheet having a substantially uniform density at least in the deposition zone.

4. The device according to any one of the preceding claims, wherein: The one or more magnetic elements are electromagnets.

5. The device according to claim 4, wherein: The apparatus comprises a controller arranged to control the magnetic field provided by one or more of the electromagnets.

6. The device according to any one of claims 1 to 3, wherein: The confinement device comprises at least two magnetic elements arranged to provide the confinement magnetic field.

7. The device according to claim 6, wherein: The at least two magnetic elements are arranged such that a region of relatively high magnetic field strength provided between the magnetic elements substantially follows the curve of the curved path.

8. The device according to any one of claims 1 to 3, wherein: The magnetic field lines characterizing the confining magnetic field are each curved so as to substantially follow the curve of the curved path at least in the deposition zone.

9. The device according to claim 8, wherein: The one or more magnetic elements comprises a solenoid having an opening through which, in use, a plasma is confined, the opening being elongated in a direction substantially parallel to a longitudinal axis of the base guide.

10. The apparatus of claim 8, further comprising a plasma generating device arranged to generate plasma, wherein the plasma generating device comprises one or more elongated antennas extending in a direction substantially parallel to a longitudinal axis of the substrate guide.

11. The apparatus according to any one of claims 1 to 3, wherein: The magnetic field lines characterizing the confining magnetic field are arranged such that an imaginary line extending perpendicular to each magnetic field line and connecting the magnetic field lines is curved so as to substantially follow the curve of the curved path at least in the deposition zone.

12. The device according to claim 11, wherein The one or more magnetic elements comprises a solenoid having an opening through which, in use, plasma is confined, the opening being curved and elongated in a direction substantially perpendicular to a longitudinal axis of the base guide.

13. The apparatus of claim 11, further comprising a plasma generating device arranged to generate plasma, wherein: The plasma generation device includes one or more elongated antennas that are curved and extend in a direction substantially perpendicular to a longitudinal axis of the substrate guide.

14. The apparatus according to any one of claims 1 to 3, wherein: The target portion is arranged such that at least a portion of the target portion defines a support surface that forms an obtuse angle relative to a support surface of another portion of the target portion.

15. The apparatus according to any one of claims 1 to 3, wherein: The target portion is substantially curved.

16. The apparatus according to any one of claims 1 to 3, wherein: The target portion is arranged substantially along or close to a curve of the curved path.

17. The apparatus according to any one of claims 1 to 3, wherein: The substrate guide is provided by a curved member which guides the substrate web along the curved path.

18. A method of sputter depositing a target material onto a substrate, the substrate being guided along a curved path by a substrate guide, wherein a deposition zone is defined between the substrate guide and a target portion supporting the target material, the method comprising: providing a magnetic field to confine the plasma in the deposition zone to cause sputter deposition of the target material onto the substrate web, the magnetic field being characterized in that the magnetic field lines are arranged to curve substantially along the curved path at least in the deposition zone to confine the plasma around the curved path, Wherein the magnetic field is provided by one or more magnetic elements, the one or more magnetic elements are in the form of a solenoid which, in use, is elongated in a direction substantially perpendicular to the direction of the magnetic field lines generated within the solenoid.

19. An apparatus for sputtering a target material onto a substrate, comprising: plasma treatment area; as well as a confinement device comprising one or more magnetic elements arranged to provide a confining magnetic field to confine the plasma in a plasma processing region, thereby providing plasma processing in use, the confinement magnetic field being characterized in that the magnetic field lines are arranged to substantially follow a curved path at least in the plasma processing region, thereby confining the plasma around the curve of the curved path, Therein, one or more magnetic elements take the form of a solenoid which, in use, is elongated in a direction substantially perpendicular to the direction of magnetic field lines generated within the solenoid.

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