NL2035766B1

NL2035766B1 - Plasma source for patterned deposition

Info

Publication number: NL2035766B1
Application number: NL2035766A
Authority: NL
Inventors: Tielen Viktor; Antonius Smeltink Jeroen; Poodt Paul
Original assignee: Sparknano B V
Priority date: 2023-09-08
Filing date: 2023-09-08
Publication date: 2025-03-14
Also published as: WO2025053756A1

Abstract

Title: PLASMA SOURCE FOR PATTERNED DEPOSITION A plasma source (100) comprises a plasma deposition head (1 10) with an aperture (1 1 1) for delivering an atmospheric plasma to a substrate (50). An electrode plate (120) is mounted in a slotted cavity (112) of the deposition head. A gas supply system (130) is arranged for supplying a mass ﬂow of gas towards the substrate through a gap (G) between the electrode plate and the deposition head. A removable insert (140) is removably mounted in the gap, the removable insert being arranged for patterning the ﬂow of atmospheric plasma towards the substrate by locally blocking a section of the slotted cavity for thereby forming a patterned channel between the gas supply system and the aperture. See [FIG 1]

Description

P135343NL00

Title: PLASMA SOURCE FOR PATTERNED DEPOSITION

The invention relates to a plasma source, e.g. for spatial atomic layer deposition.

In spatial atomic layer deposition (ALD), a substrate is sequentially exposed to half-reactions, e.g. as in plasma enhanced ALD, where one of the half-reactions is formed by plasma species. An ALD plasma deposition head typically comprises a high voltage electrode, to generate a plasma, which is supplied towards the substrate as it moves with respect to the deposition head, or vice versa. In this way, the substrate can be manufactured additively by depositing various layers. Patterns or tracks can be made on the substrate by locally interrupting the half reactions, e.g. by controlling the supply of plasma towards the substrate. Generally, in such patterned depositions, 1t is important that the dimensions of the pattern can be controlled within small tolerances. This allows the resolution of the patterned substrate to be increased. Or, in other words, the interdistance between edges of the pattern can be reduced. In this respect, the edges of the pattern need to be as sharp, or well-defined, as possible. For example, the edge width, defined as the width of the transition between deposition and no-deposition on the substrate, is preferably as small as possible, e.g. smaller than 0.5 mm.

It is known to create a pattern on the substrate by patterning the electrode plate itself. For example, the metal electrode inside the dielectric may be interrupted, e.g. by consisting of separate parts, over the width of the electrode plate. However, such a patterned electrode may produce relatively wide (non-sharp) edges in the pattern on the substrate, e.g. due to diffusion of the radicals as they flow towards the substrate. Also, since each patterned electrode is specifically designed to produce a certain pattern on the substrate, the electrode is to be replaced in order to have the plasma source produce a different pattern. In general, electrode plates are expensive and fragile, so having a patterned electrode may not be preferred in practice.

It is an object of the present invention to provide a simple and flexible solution to reduce the edge width of ALD patterns.

SUMMARY

In summary, the invention provides a plasma source comprising a plasma deposition head, an electrode plate, and a gas supply system. The plasma deposition head comprises an aperture for delivering an atmospheric plasma from the deposition head to a substrate, and comprises a slotted cavity extending from the aperture. The electrode plate is mounted in the slotted cavity and extends from an interior of the deposition head towards the aperture. The gas supply system is arranged for supplying a mass flow of gas towards the substrate through a gap between the electrode plate and the deposition head, and the electrode plate is arranged for generating atmospheric plasma in the mass flow of gas.

A removable insert is removably mounted in the gap. The removable insert is arranged for patterning the flow of atmospheric plasma towards the substrate by locally blocking a section of the slotted cavity for thereby forming a patterned channel between the gas supply system and the aperture.

Accordingly, the removable insert creates a patterned atomic layer deposition on the substrate by locally allowing and preventing the formation of plasma along the electrode plate. By locally interrupting, e.g. blocking, the mass flow of gas, radicals formed in the plasma are guided towards the substrate via distinct passages adjacent to the interruption, thereby minimalizing diffusion of the radicals and reducing pattern edge widths.

Since the insert is removable, hence interchangeable, the pattern of the gas flow towards the substrate can be changed by replacing the insert with a different type or differently shaped insert. In other words, the pattern of the layer deposition can be selectively altered without modifying the electrode plate or deposition head, by mounting different types of insert in the gap.

The removable insert can e.g. be made from a material which is readily available and which can be machined with high precision, such as a plate material, for providing the patterned channel in the gap. For example, the removable insert can be provided with grooves, cutouts, holes, or ribs.

The patterned channel is at least partially formed by the removable insert.

For example, some walls of the patterned channel may be formed by walls of the slotted cavity and/or sides of the electrode plate, while other patterned channel walls are formed by the removable insert. Alternatively, the patterned channel may be entirely integral to the removable insert, e.g. by holes or slots in the removable insert.

Preferably, the removable insert comprises one or more cutouts that extend between the gas supply system and the aperture, to guide the mass flow of air.

In some embodiments, the removable insert comprises a plurality of shims arranged in a stack. For example, each shim has a thickness and a number of shims are stacked to obtain a total thickness of the removable insert for bridging the gap between the electrode plate and the deposition head. By thus adapting the total thickness of the removable insert, e.g. to match the gap width, different types of plasma source can be provided with a replaceable, modifiable patterned channel between the electrode plate and the deposition head.

Preferably, at least one shim of the plurality of shims is provided with cutouts that extend between the gas supply system and the aperture.

In some embodiments, the gas supply system comprises a plurality of gas supply channels and outlets that emerge into the slotted cavity across the width of the electrode plate, and the removable insert substantially spans the width of the electrode plate. The removable insert may selectively close off some of the gas supply channels and outlets, while others are left open by cutouts in the removable insert that extend towards the aperture.

In this way, the mass flow of gas supplied by the gas supply system is locally interrupted, or allowed to pass along the one or more shims.

The plasma source may comprise more than one removable insert.

For example, each removable insert only spans a part of the width of the electrode plate to locally block a section of the slotted cavity, so that other sections of the slotted cavity are not provided with a removable insert. For example, the removable insert may only be mounted in a central portion of the gap between the electrode plate and the deposition head, so that distinct channels are formed on opposing lateral sides of the removable insert.

To further reduce the edge width of the pattern created on the substrate, the one or more removable shim plates may divide the gap into first channels for directing a first portion of the mass flow of gas adjacent the electrode plate, and second channels isolated from the electrode plate for directing a second portion of the mass flow of gas. As a result, in use, atmospheric plasma is generated in the first portion, while no plasma is generated in the second portion. In this way, the second portion of the mass flow of gas can be used to purge the flow of atmospheric plasma. Preferably, the first and second channels are arranged in an alternating pattern over a width of the electrode plate. By enabling a supply of purge gas adjacent to, e.g. alternating with, the patterned supply of plasma gas, (lateral) diffusion of the plasma gas can be further limited.

Preferably, the gas supply system is arranged for supplying the first portion of the mass flow of gas through the first channels and for supplying the second portion of the mass flow of gas through the second channels, wherein the first portion is equal to the second portion. When the supplies of gas through the first and second channels are substantially equal in mass flow, a flow of purge gas can be realized that optimally counteracts the flow of atmospheric plasma, thereby reducing the pattern 5 edge width.

The first channels can e.g. be defined by first cutouts in one or more first shims, and the second channels can e.g. be defined by second cutouts in one or more second shims.

Preferably, the removable insert is clamped between the electrode plate and the deposition head, to facilitate installing and replacing the removable insert.

In some embodiments, the removable insert is made of an electrically conductive material, for locally providing an electrical connection between the electrode plate and the deposition head. As a result, the potential difference between the electrode plate and the deposition head is locally minimized, e.g. in areas between distinct channels of the patterned channel. Accordingly, in use, plasma is generated only in the channels.

Preferably, the electrode plate comprises a high voltage electrode that substantially spans a width of the electrode plate in a continuous fashion. Thus, instead of patterning the electrode itself, e.g. by an interrupted high voltage electrode, the electrode plate is able to generate plasma over the full width of the electrode plate. In this way, an optimal degree of flexibility is provided in patterning the substrate, since the pattern is only dependent on the removable and interchangeable (set of) shim plates mounted in the gap between the electrode plate and the deposition head.

In some embodiments, the electrode plate 1s suspended at a distance from each parallel wall of the slotted cavity, wherein the gas supply system is arranged for supplying a first and second mass flow of gas through respective first and second gaps on opposing sides of the electrode plate,

wherein a removable insert is removably mounted in the first and second gap.

The present invention is not limited to removable inserts for patterning a flow of plasma gas, but can also be applied to pattern non- plasma gases such as a precursor gas. By patterning a flow of precursor gas towards the substrate, a corresponding pattern can be formed on the substrate as well. An even better edge sharpness of the deposited pattern can be provided by patterning both the flow of plasma gas as well as the flow of precursor gas towards the substrate.

For example, the plasma deposition head may comprise a further aperture for delivering a flow of precursor gas from the deposition head to the substrate, and a further slotted cavity extending from the further aperture, wherein the gas supply system is arranged for supplying the flow of precursor gas towards the substrate through the further slotted cavity, wherein a further removable insert is removably mounted in the further slotted cavity, the further removable insert being arranged for patterning the flow of precursor gas towards the substrate by locally blocking a section of the further slotted cavity for thereby forming a further patterned channel between the gas supply system and the further aperture.

Preferably, the further removable insert forms a further patterned channel that is identical to patterned channel formed by the removable insert, to maximize the edge sharpness of the pattern deposited on the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further elucidated in the figures:

FIG 1 illustrates an embodiment of a plasma source provided with removable shims;

FIGs 2A and B illustrate a mass flow of gas through the plasma source of FIG 1, and the resulting pattern on a substrate;

FIG 3 illustrates another embodiment of the plasma source, comprising a stack of removable shims;

FIG 4 provides yet another embodiment of the plasma source, comprising first and second removable shims;

FIGs 5A and B illustrate a mass flows of gas through the plasma source of FIG 4, and the resulting pattern on a substrate;

FIG 6 illustrates yet another or further embodiment of the plasma source described herein; and

FIG 7 depicts an embodiment of a removable shim of the plasma source described herein.

DETAILED DESCRIPTION

The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and/or cross-section illustrations of possibly idealized embodiments and intermediate structures of the invention. In the description and drawings, like numbers refer to like elements throughout. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise.

FIG 1 provides a top view of an embodiment of a plasma source 100, arranged for generating a patterned flow of atmospheric plasma, in particular to perform plasma enhanced (spatial) atomic layer deposition on a substrate 50. In use, the substrate 50 and the plasma source 100 are moved with respect to each other, e.g. along movement direction D, and the plasma source 100 delivers a flow of atmospheric plasma towards the substrate 50 from a deposition head 110, comprising an aperture facing the substrate 50. The aperture is formed by edges of a rectangular slotted cavity 112 in the deposition head 110. Preferably, the aperture is oriented perpendicular to movement direction D. For example, a length of the slotted cavity 112 spans at least a portion of the width of the substrate 50.

An electrode plate 120 1s mounted against a first parallel wall 114 of the slotted cavity 112, such that a gap G is formed between the electrode and an opposing second parallel wall 113 of the slotted cavity. The electrode plate 120 comprises a high voltage electrode that substantially spans a width of the electrode plate 120, and is arranged for generating a potential difference between the electrode plate and the opposing second parallel wall 113 of the slotted cavity. A mass flow of gas is supplied through the gap G, from a gas supply system towards the aperture. As the mass flow of gas in use passes along the electrode plate, the potential difference across the gap

G converts the gas to (atmospheric) plasma.

The flow of atmospheric plasma is patterned, e.g. interrupted in a direction perpendicular to movement direction D, to deposit parallel tracks onto the substrate 50, e.g. as illustrated in FIGs 2A and B. To achieve this, a removable insert 140 is mounted in the slotted cavity 112, e.g. spanning the gap G between the electrode plate 120 and the opposing parallel wall 113.

The removable insert 140 blocks a section of the gap G, while allowing passage of gas through other sections of the gap G, thereby effectively creating distinct, separate channels adjacent to the insert.

The insert 140 is removable in that the insert 140 can be mounted inside the gap G, and removed therefrom without changing the design or configuration of other parts of the plasma source 100, such as the electrode plate 120 or the deposition head 110. Thus, the removable insert 140 is interchangeable, e.g. with other types or shapes of removable insert 140 that are arranged for providing other flow patterns of the atmospheric plasma. The removable insert 140 can for example be fixed to the deposition head 110 or to the electrode plate 120 by screws or pins, or may be clamped between the deposition head 110 and the electrode plate 120 to facilitate installation and removal. Preferably, the removable insert 140 comprises alignment means, such as holes, protrusions or edges, arranged for aligning the shim plate 140 with respect to the electrode plate 120 and/or the deposition head 110.

The removable insert 140 is arranged for locally interrupting the mass flow of gas between the gas supply system and the aperture. In other words, the removable insert 140 locally prevents the passage of gas through some sections of the gap G, while allowing passage through other sections along the electrode plate 120 and towards the aperture 111. In this way, atmospheric plasma is only generated along unblocked sections of the gap G, a patterned flow of atmospheric plasma is provided towards the substrate 50.

The removable insert 140 preferably continuously extends between the gas supply system and the aperture, thus along the direction of the gas flow therebetween, preferably up until, or slightly offset from, the aperture.

As a result, distinct channels are formed for guiding portions of the mass flow of gas separately through the gap G until they reach the aperture. In this way, it is prevented that the separated flows of gas would join each other or diffuse laterally before reaching the substrate 50.

Preferably the removable insert 140 is made of an electrically conductive material, in particular a material with an electrical conductivity larger than 1x10° Siemens per meter, e.g. a metal or metal alloy such as steel or aluminium. In this way, in blocked sections where the shims form a bridge between the electrode plate 120 and the deposition head 110, the potential difference across the gap G is locally reduced, to prevent the formation of plasma in those sections.

FIG 3 illustrates a side view of an embodiment of the plasma source 100. The plasma deposition head 110 1s suspended above a substrate 50, and comprises a slotted cavity 112 in which an electrode plate 120 is mounted. The electrode plate 120 comprises a high voltage electrode plate 121 enclosed in a dielectric material, such as aluminium oxide. A gas supply system 130 is arranged for supplying a mass flow of gas through a gap G between the electrode plate 120 and the deposition head 110. In use, the substrate 50 and the plasma deposition head 110 move with respect to each other, e.g. along movement direction D, while the gas supply system 130 supplies a mass flow of gas through the gap G towards an aperture 111 facing the substrate 50.

A potential difference is created between the electrode plate 120 and the deposition head 110 across the gap G, to convert the mass flow of gas to an atmospheric plasma, thereby exposing the substrate 50 to a half- reaction. As a result, a layer of material is deposited on the substrate 50.

As illustrated in FIG 3, a stack of shims 140 is mounted in the gap

G between the electrode plate 120 and the deposition head 110. For example, the stack of shims 140 comprises a number of plates that are stacked. Each plate has a thickness that spans a part of the gap G. When stacked together, the thicknesses of the shims 140 add up to match a width of the gap G. Each shim plate 140 may be provided with cutouts, holes, or grooves that extend between the gas supply system 130 and the aperture. In this way, when stacked together, the shim plates 140 form a channel structure for locally blocking and allowing passage of the mass flow of gas towards the substrate 50.

Thus, the stack of shims 140 is arranged for locally interrupting (e.g. blocking) the mass flow of gas towards the aperture in some sections of the gap G, in particular over a width of the electrode plate 120, while also allowing passage of the mass flow of gas in other sections of the gap G.

Accordingly, as the deposition head 110 and the substrate 50 move with respect to each other along the movement direction D, some parts of the substrate 50 are not exposed to the flow of atmospheric plasma. As a result, material is deposited on the substrate in a pattern. Such a pattern e.g. comprises parallel tracks along the movement direction D.

FIG 4 provides a top view of another embodiment of the plasma source 100. Here, the removable insert 140 comprises a first shim 140-1 and a second shim 140-2, to divides the gap G into first channels 142 adjacent the electrode plate 120 and second channels 143 isolated from the electrode plate 120, e.g. by a part of the removable insert 140 still covering the electrode plate. The first channels 142 are arranged for allowing atmospheric plasma to be generated in a first portion of the mass flow of gas directed through the first channels 142 towards the substrate 50. The second channels 143 prevent the formation of atmospheric plasma gas in a second portion of the mass flow of gas directed through the second channels 143, by being isolated from, e.g. at an offset to, the electrode plate 120. In this way, the second portion can be used to purge the flow of atmospheric plasma delivered via the first channels 142. The first channels 142 and second channels 143 are arranged in an alternating pattern over the width of the electrode plate 120, e.g. forming a checkerboard pattern. For example, the first channels 142 are defined by first cutouts 141-1 in the first shim 140-1, while the second channels 143 are defined by second cutouts 141-2 in the second shim 140-2. Preferably, the first and second cutouts 141-1, 141-2 do not overlap, to prevent mixing of the first and second portion when these are still traveling through the gap G, thus before being delivered to the substrate 50.

Instead of comprising a stack of shims 140-1, 140-2, a single removable insert 140 can be mounted between the electrode plate 120 and the deposition head 110, which single removable insert 1s provided with a number of first cutouts or grooves arranged for allowing the first portion of the mass flow of gas to be delivered to the substrate 50, and a number of second cutouts or grooves arranged for allowing the second portion to be delivered to the substrate 50.

By providing first channels 142 and second channels 143 that alternate along the width of the electrode plate, the edge width of the pattern deposited on the substrate can be further reduced, as illustrated in

FIGs 5A and B. The flow of “purge gas” provided via the second channels reduces lateral diffusion of the flow of atmospheric plasma delivered to the substrate 50. This can be optimized by matching the mass flows of the first and second portions. For example, the gas supply system can be arranged for supplying substantially equal mass flows of gas through the first and second channels 142, 143.

FIG 6 provides yet another or further exemplary embodiment of the plasma source 100. Here, the plasma deposition head 110 comprises, besides the slotted cavity 112 for guiding the flow of plasma gas along the electrode plate 120, a further slotted cavity 112’ that extends from a further aperture for delivering a flow of non-plasma gas, e.g. precursor gas, from the deposition head to the substrate 50. The slotted cavity 112 and further slotted cavity 112’ can be provided in a single body of the plasma deposition head 110, e.g. as illustrated in FIG 6, but may also be provided in separate bodies that are mounted to each other, e.g. to accommodate other parts of the deposition head therebetween.

A further removable insert 140’ is removably mounted in the further slotted cavity 112’, for patterning the flow of non-plasma gas towards the substrate 50 by locally blocking a section of the further slotted cavity 112’ for thereby forming a further patterned channel between the gas supply system and the further aperture.

FIG 7 illustrates an exemplary embodiment of a removable insert 140, shown in relation to a high voltage electrode 121 of the electrode plate of the plasma source 100 described herein. Preferably, the removable insert 140 is provided with an alignment arrangement 145, e.g. comprising holes,

edges, or protrusions, that is arranged to align the removable insert 140 with respect to the electrode plate and/or the deposition head.

The removable insert 140 is arranged for locally interrupting the mass flow of gas M that in use passes over the high voltage electrode 121, e.g. by comprising a number of cutouts 141 that expose the high voltage electrode 121, and a number of obstructions 144 that cover the high voltage electrode 121.

The invention applies not only to ALD applications where the plasma source provides an improved patterned atomic layer deposition on the substrate, but also to other technical, agricultural or industrial applications where patterned layer deposition is applied, e.g. in chemical vapor deposition (CVD). Instead of being mounted in a plasma gas channel, the removable shim can also be mounted in non-plasma gas slots, for thereby patterning the flow of non-plasma gas. For example, alternatively or additionally, the removable shim can be mounted in a precursor gas slot for guiding a flow of precursor towards the substrate, wherein the removable shim is arranged for patterning the flow of precursor gas, to provide an alternative or additional way of patterning the substrate.

It will be clear to the skilled person that the invention is not limited to any embodiment herein described and that modifications are possible which may be considered within the scope of the appended claims.

Also, kinematic inversions are considered inherently disclosed and can be within the scope of the invention. In the claims, any reference signs shall not be construed as limiting the claim.

The terms ‘comprising’ and ‘including’ when used in this description or the appended claims should not be construed in an exclusive or exhaustive sense but rather in an inclusive sense. Thus, expression as including’ or ‘comprising’ as used herein does not exclude the presence of other elements, additional structure or additional acts or steps in addition to those listed. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. Features that are not specifically or explicitly described or claimed may additionally be included in the structure of the invention without departing from its scope.

Expressions such as: "means for ...” should be read as: "component configured for ..." or "member constructed to …" and should be construed to include equivalents for the structures disclosed. The use of expressions like: "critical", "preferred", "especially preferred" etc. is not intended to limit the invention. To the extent that structure, material, or acts are considered to be essential they are inexpressively indicated as such. Additions, deletions, and modifications within the purview of the skilled person may generally be made without departing from the scope of the invention, as determined by the claims.

Claims

CONCLUSIONS

1. A plasma source (100), comprising: - a plasma deposition head (110) comprising an opening (111) for delivering an atmospheric plasma from the plasma deposition head to a substrate (50), and comprising a slot cavity (112) extending from the opening (111); and - an electrode plate (120) mounted in the slot cavity (112) and extending from an inside of the deposition head (110) toward the opening (111); - a gas supply system (130) adapted to supply a mass flow of gas toward the substrate (50) through a space (G) between the electrode plate (120) and the deposition head (110), the electrode plate (120) being adapted to generate atmospheric plasma in the mass flow of gas; wherein a removable insert (140) is removably disposed in the space (G), the removable insert (120) being adapted to pattern the flow of atmospheric plasma toward the substrate (50) by locally blocking a portion of the slot cavity (112) to thereby form a patterned channel between the gas supply system (130) and the opening (111).

The plasma source (100) of claim 1, wherein the removable insert (140) comprises one or more recesses (141) extending between the gas supply system (130) and the opening (111).

The plasma source (100) of any preceding claim, wherein the removable insert (140) comprises a plurality of stacked shims.

The plasma source (100) of claim 3, wherein at least one of the plurality of shims has recesses (141) extending between the gas supply system (130) and the opening (111).

The plasma source (100) of any preceding claim, wherein the removable insert (140) defines one or more first channels (142) adjacent to the electrode plate (120) for conducting a first portion of the mass flow of gas, and one or more second channels (143) isolated from the electrode plate (120) for conducting a second portion of the mass flow of gas, the one or more first and second channels (142, 143) being arranged in an alternating pattern across a width of the electrode plate (120).

The plasma source (100) of claim 5, wherein the gas supply system (130) is configured to supply the first portion of the mass flow of gas through the one or more first channels (142), and to supply the second portion of the mass flow of gas through the one or more second channels (143), the first portion being equal to the second portion.

The plasma source (100) of claim 5 or 6, wherein the first channels (142) are defined by first recesses (141-1) in one or more first shims (140-1), and wherein the second channels (143) are defined by second recesses (141-2) in one or more second shims (140-2).

The plasma source (100) of any preceding claim, wherein the removable insert (140) is clamped between the electrode plate (120) and the deposition head (110).

The plasma source (100) of any preceding claim, wherein the removable insert (140) comprises an alignment device (145) adapted to align the removable insert (140) with respect to the electrode plate (120) and/or the deposition head (110).

The plasma source (100) of any preceding claim, wherein the removable insert (140) is made of an electrically conductive material to locally provide an electrical connection between the electrode plate (120) and the deposition head (110).

The plasma source (100) of any preceding claim, wherein the electrode plate (120) comprises a high voltage electrode (121) extending substantially across a width of the electrode plate (120) in a continuous manner.

The plasma source (100) of any preceding claim, wherein the electrode plate (120) is suspended at a distance from each parallel wall (113, 114) of the slot cavity (112), the gas supply system (130) being adapted to supply a first and second portion of the mass flow of gas through respective first and second spaces (G1, G2) on opposite sides of the electrode plate (120), a removable insert being removably disposed in the first and second spaces (G1,

G2).

The plasma source (100) of any preceding claim, wherein the plasma deposition head (110) comprises a further aperture for delivering a stream of precursor gas from the deposition head to the substrate (50), and a further slot cavity (112°) extending from the further aperture, the gas supply system (130) adapted to supply the stream of precursor gas through the further slot cavity (112°) towards the substrate (50), a further removable insert (140°) removably disposed in the further slot cavity (112), the further removable insert (140°) adapted to pattern the stream of precursor gas towards the substrate (50) by locally blocking a portion of the further slot cavity (112°) to thereby form a further patterned channel between the gas supply system and the further aperture.

The plasma source (100) of claim 13, wherein the further removable insert (140°) forms a further patterned channel identical to the patterned channel formed by the removable insert (140).