Apparatus for wet treating a flat workpiece, device for a cell of the apparatus and method of operating the apparatus

Abstract

A device for a cell of an apparatus for wet processing flat workpieces comprises a structure having a first wall (13a) and a second wall (13b). The workpiece is movable in a first direction (y) within a central plane (4) through a space (3) between the first wall (13a) and the second wall (13b). Openings (27) for introducing pressurized liquid between the first wall (13a) and the second wall (13b) are provided facing the central plane (4) on opposite sides of the central plane (4). The openings (27) are distributed in the first direction (y) and a second direction (x) transverse to the first direction (y). Discharge openings (28a, 28b) for liquid exiting the space (3) are defined on opposite sides of the space (3) in the first direction (y) as viewed in the second direction (x). The first wall (13a) and the second wall (13b) form a barrier to the flow of liquid from the space in a direction (z) perpendicular to the central plane (4). Passages (23a, 23b, 24a, 24b) extend through the walls (13a, 13b), each positioned to direct liquid to a respective one of the openings (27).

Description

Technical Field

[0001] The present invention relates to a device for a cell of an apparatus for wet processing a flat workpiece, comprising a structure having a first wall and a second wall, the workpiece being movable in a first direction within a central plane through a space between the first wall and the second wall, openings for introducing a pressurized liquid between the first wall and the second wall being provided facing the central plane on opposite sides of the central plane, the openings being distributed in the first direction and in a second direction transverse to the first direction, discharge openings for the liquid to exit the space being defined on opposite sides of the space as seen in the second direction along a range of the space in the first direction, and the first wall and the second wall forming a barrier to the flow of liquid from the space in a direction perpendicular to the central plane. The present invention relates to a device.

[0002] The present invention also relates to an apparatus for wet processing a flat workpiece.

[0003] The present invention also relates to a method of operating such an apparatus.

[0004] The present invention also relates to the use of at least one of such a device and such an apparatus.

[0005] Background Art U.S. Patent Application Publication No. 2015 / 0252488 discloses a plater for wet chemical electrochemical treatment that is electrochemically deposited on the surface of a material to be treated. This device has sidewalls disposed on the sides that extend parallel to the transport direction of the material to be treated, and a bottom wall that partitions the treatment chamber. Further, the treatment chamber is closed transversely to the transport direction by additional sidewalls having slots for transporting the material to be treated. A pair of squeezing rollers are disposed in these slots to seal the liquid treatment chamber against the outflow of the treatment liquid, and the material to be treated is guided through between the squeezing rollers when being carried into or out of the treatment chamber. The material to be treated is transported by wheels mounted on shafts at a certain distance from each other, and the shafts extend transversely to the transport direction. The anodes are disposed above and below the material to be treated. The transport surface extends in the transport direction within the treatment chamber. When viewed from the transport surface beyond the anode, the supply device having nozzles is located above and below the material to be treated. The supply device is formed by a top water channel and a bottom water channel, and transports the treatment liquid to the surface of the material to be treated through the nozzles on both sides. The nozzles and the remaining components are disposed below the tank water level of the treatment chamber. There is no wall above the supply device located above the material to be treated during use. The anodes do not form a barrier to the flow of liquid in a direction perpendicular to the central plane from the space between the anodes. The wheels for transporting the material to be treated contact the material to be treated at positions along the entire width of the material to be treated. This is undesirable when the material to be treated is relatively fragile, for example, when covered with a photomask. When the wheels are omitted, it is necessary to maintain a relatively large distance between the anode and the material to be treated to prevent the material from contacting the anode. Even so, due to the undulations across the width of the material to be treated, the distance between the anode and the material varies, which may lead to the formation of non-uniform coatings.

[0006] Japanese Patent Application Laid-Open No. 4229403 discloses an apparatus capable of plating the upper and lower surfaces of a thin plastic foil having through holes and the side surfaces of the through holes. The plating chamber is provided with a housing, the inlet of which is formed by a pair of squeezing rollers, and the outlet of which is formed by a pair of squeezing rollers. The upper anode and the lower anode extend parallel to and spaced apart from above and below the plastic foil. Each distribution space for the electrolyte is provided between the anode and the housing of the plating chamber. The anode is provided with a plurality of through holes inclined with respect to the moving direction of the plastic foil, and as a result, they converge in the moving direction. The electrolyte supplied to the distribution space through the conduit enters the space between the anode and the plastic foil with a moving component parallel to the moving direction of the plastic foil. The electrolyte flows out from the side opening of the housing and enters the liquid reservoir of the apparatus from there. The side opening is provided only at one location along the length of the chamber. The plastic foil is unwound and wound up by reels at both ends of the apparatus and is firmly held flat by a pair of squeezing rollers. Therefore, this configuration is only suitable for the treatment of endless foils, and it is necessary to firmly contact the squeezing rollers with the foil over the width of the foil.

[0007] WO 98 / 49374 discloses an apparatus for electrolytically treating circuit boards and circuit foils in a horizontal continuous apparatus using direct or pulsed current. The apparatus comprises an upper insoluble anode and a lower insoluble anode which function as counter electrodes. The electrolytic cell is formed by the upper anode, the circuit board or circuit foil, and the electrolyte space therebetween. The anodes extend essentially over the entire width of the workpiece. The circuit boards and circuit foils are preferably conducted centrally by upper and lower guide elements between the upper and lower anodes and are conveyed by clamps which also function as electrical contact elements. The guide elements are generally electrically insulated narrow spindles on which perforated disks of non-conductive plastic are mounted. The electrolyte spraying device is arranged outside the electrolyte space on the side of the counter electrode opposite the conveying surface. The spraying tube is provided with holes or nozzles directed perpendicular or at a predetermined angle to the surface of the workpiece. The anode is provided with holes and is positioned such that the treatment liquid emerging from the holes or nozzles of the spraying tube can pass through the anode without substantial or complete hindrance. However, the anode does not form a barrier preventing the flow of liquid in a direction perpendicular to the conveying surface from the conveying surface. The spraying tube is positioned sufficiently spaced from the upper and lower walls of the device. Thus, perforated disks are required to hold the circuit board or circuit foil on the conveying surface.

[0008] Although having the same configuration as that shown in International Publication No. 98 / 49374, a device without a perforated disk on the spindle is used in the horizontal continuous plating apparatus currently available from the applicant. In this apparatus, spray bars provided on opposite sides of a plane arranged so that a workpiece is conveyed are directed toward that plane. The distance from the spray bars to the moving surface of the workpiece is relatively small. Therefore, there is a risk that a thin workpiece may undulate and contact a contact protection grid provided between the anode and the moving surface. In the case of dry film electroplating, as a result, the photomask may come off the workpiece. Even if contact is avoided, since one or more relatively rigid metal layers are formed on one or more surfaces of the workpiece, the undulation may be fixed.

[0009] Summary of the Invention The object of the present invention is to improve the devices, apparatuses and methods of the form defined in the opening paragraph above so that the processing of relatively thin workpieces is made possible while holding the workpiece relatively well within a single plane.

[0010] According to a first aspect, this object is achieved by a device according to the invention, characterized in that passages are provided through the walls, each passage being arranged to conduct liquid to one of the respective openings.

[0011] The device may be for forming a complete cell or may be configured to be placed in a tank for forming a cell. In the latter case, the space allowing access to the liquid introduced between the mutually facing surfaces of the first wall and the second wall is larger than the space section between these mutually facing surfaces. In one embodiment, a plurality of devices can be provided in a single tank to form a cell. The type of treatment can include at least one of wet chemical treatments, such as chemical metal deposition or electrolytic metal deposition, chemical etching or electrolytic etching, and chemical cleaning or electrolytic cleaning. At least a part of the liquid introduced through the opening contains reactants, whereby the flow of the liquid on the surface of the workpiece provides replenishment of the reactants and thus more efficient treatment. The surface treatment of the workpiece can be performed on only one surface or both surfaces of the workpiece, but the liquid flow exists across both surfaces.

[0012] In one embodiment, the device is for forming a cell configured to apply electroplating, such as pulse electroplating, to a workpiece.

[0013] The workpiece may be a plate or a foil. The workpiece may be a particularly separate plate or foil piece, as opposed to a foil conveyed from reel to reel via a device. This device is particularly suitable for a device for processing a relatively thin and relatively flexible flat workpiece having a thickness on the order of, for example, 10 to 100 μm. This is because such a workpiece is more likely to bend. However, the device can also be used for a device for processing a thicker workpiece.

[0014] The workpiece is movable in a first direction within the central plane between the first wall and the second wall. The first direction, which is also referred to herein as the longitudinal direction, is defined simply by the direction of movement. The first direction does not need to correspond to the maximum dimension of the device or the space into which the liquid is introduced.

[0015] The device has a structure comprising a first wall and a second wall. These first and second walls do not need to be joined or form part of a single assembly. However, the first and second walls are mounted so as to present facing surfaces that delimit at least part of a space allowing access to a liquid introduced between the walls. A liquid-permeable structure can be inserted between the walls. However, except for the passageways, the walls are impermeable to the liquid, so the walls form a barrier. The first and second walls function as backflow barriers against openings for introducing liquid into the space between the walls. Thus, the first and second walls form part of the boundary of a space allowing access to the liquid introduced between the walls. Such liquid is prevented from flowing directly from the side of the first and second walls closest to the central plane to the opposite back sides of the first and second walls, but the liquid can be collected by a recirculation system comprising at least one pump and returned as pressurized liquid.

[0016] Passageways are provided through the first and second walls, and each passageway is arranged to direct liquid to one of each plurality of openings for introducing liquid into the space between the first and second walls. The openings for introducing liquid are provided facing the central plane on opposite sides of the central plane. Thus, the direction of flow is mainly towards the discharge opening, or otherwise towards the central plane near the opening. To establish such a flow field, the openings can be defined at the ends of the respective passageways in the surface. If the openings are defined at the distal ends of nozzles protruding from the surface, these nozzles protrude only a relatively short distance from the surface such that the walls in question still function as backflow barriers.

[0017] The openings are distributed in a first direction and a second direction transverse to the first direction, or a lateral direction, so that the pressurized liquid is introduced at multiple locations across the surface of the wall. Thereby, the liquid flow accelerates in the opposite lateral direction towards the discharge opening. During operation, the discharge opening is located at the side edge of the workpiece moving through the device. Depending on the extent to which the space in which the workpiece is movable is closed at the longitudinal ends of that space, the flow in the first direction is restricted or there is no flow in the first direction at all.

[0018] A section of the flat workpiece deviating from the central plane towards one of the opposite surfaces locally narrows the already narrow gap between that surface and the workpiece. As a result, the flow is pinched and the pressure rises locally. The pressure decreases locally on the opposite side of the workpiece. The resulting force tends to return the workpiece section towards the central plane. A workpiece section moving towards the nozzle orifice is subject to a local impact, but does not experience a net force returning this section towards the central plane, so this restoring effect cannot be achieved with a nozzle directing a spreading jet towards the surface of the workpiece. This is because there is no backflow barrier immediately behind the nozzle.

[0019] In contrast, in the present device, the workpiece is substantially maintained in the central plane by the liquid flow on either side. As a result, the space in which the workpiece is movable can have a relatively low height. Thus, the amount of liquid to be circulated is relatively small and the device is relatively compact. Unintended contact between the surface of the workpiece and the device is avoided. Solid guide elements contacting the surface of the workpiece so as to move away from the side edges of the workpiece can be omitted, at least between the longitudinal ends of the device. The workpiece does not need to be held under tension in the second lateral direction.

[0020] The liquid discharge openings are defined on opposite sides of the space as viewed in the second direction and are provided along the extent of the space in the first direction, so that the liquid flow is directed laterally outward from the middle to both sides. If the flow is only from one edge of the workpiece to the opposite edge in the second direction, a thin workpiece should start to flap like a flag in the wind, especially if the workpiece is supported by only one of those edges.

[0021] As described above, in one embodiment of the device, the openings are defined at the ends of the respective passages on the surfaces of the first wall and the second wall.

[0022] That is, the passage is substantially a through-hole between the first wall and the second wall. The passage ends of the openings are at least coplanar with the surface of the wall. This, firstly, helps to establish the desired flow field. Secondly, the first wall and the second wall can be positioned closer to each other.

[0023] One embodiment comprises a first liquid distribution device and a second liquid distribution device, the first wall and the second wall respectively comprising the walls of the first liquid distribution device and the second liquid distribution device, and the liquid distribution devices being mounted such that a space extends between the liquid distribution devices.

[0024] This embodiment has a relatively small number of components.

[0025] In one embodiment of the device, at least one liquid distribution space extending in the second direction across the inlet of the passage is defined on the side of at least one of the first wall and the second wall opposite the space.

[0026] In particular, a first liquid distribution space may exist on a side of the first wall opposite to the side facing the central plane, and a second liquid distribution space may exist on a side of the second wall opposite to the side facing the central plane. When the device includes a first liquid distribution device and a second liquid distribution device, the liquid distribution space can be defined within respective chambers of the liquid distribution devices. The liquid distribution space equalizes the liquid pressure on the upstream side of the passage penetrating the first wall and the second wall. Thus, each liquid distribution space generally extends in a first direction and a second direction across the inlets of a plurality of passages. Each liquid distribution space can extend substantially over a predetermined range in the first direction and / or the second direction of the wall on the side where the liquid distribution space is defined.

[0027] In a specific example of this embodiment, the liquid distribution space is partitioned by a barrier inclined with respect to the wall such that the liquid distribution space tapers towards the edge of the wall.

[0028] There is an effect that it is only necessary to introduce the liquid into the liquid distribution space on one side of the liquid distribution space. The liquid can be introduced through one or more elongated openings extending in the first direction or the second direction at or near one edge of the liquid distribution space and generally parallel thereto. The liquid distribution space decreases in height towards the opposite edge (relative to the first wall or the second wall). As a result, a relatively uniform outlet velocity of the liquid across the opening is achieved without providing a liquid inlet for pumping the liquid into the liquid distribution space along a plurality of edges of the liquid distribution space.

[0029] An example of an embodiment of a device in which a liquid distribution space is defined on the opposite side of at least one of the first wall and the second wall with respect to the space includes at least one expanding liquid conduit having an inlet connectable to a liquid supply conduit on one side and widening towards the opposite side that is in liquid communication with the liquid distribution space at a plurality of locations along the width of the expanding liquid conduit.

[0030] This embodiment requires only a limited number of connections to the tubular conduits that convey liquid from the pump. Nevertheless, a uniform flow along the edges of the liquid distribution space is achieved. In one embodiment, the diverging conduit can be provided with a flow guide along at least a portion of its length, for example, at the wider end of the diverging conduit. This helps to avoid turbulent flow. The liquid communication with the liquid distribution space at a plurality of locations along the width of the diverging liquid conduit can be through a plurality of separate openings distributed along the width of the diverging liquid conduit. Alternatively, a single opening can extend along substantially the entire width corresponding to at least 90% or at least 95% of the width of the diverging liquid conduit, for example, along most of the width of the diverging liquid conduit.

[0031] In an example of this embodiment of a device comprising a first liquid distribution device and a second liquid distribution device, with the first wall and the second wall comprising the wall of the first liquid distribution device and the wall of the second liquid distribution device respectively, and the liquid distribution devices being mounted such that a space extends between the liquid distribution devices, the diverging liquid conduit and the liquid distribution space are defined within a chamber within the housing of one of the first liquid distribution device and the second liquid distribution device by a barrier extending into the chamber.

[0032] This results in a small-sized structure with relatively few seal connections between different components and thus a relatively low risk of leakage.

[0033] In one embodiment of the device, at least one of the discharge openings is formed by a single gap extending along a range in a first direction of the space between liquid-impermeable portions facing each other, for example, between the edge of the first wall and the edge of the second wall.

[0034] Can the edge section of the workpiece be extended through the discharge opening and held outside the space between the first wall and the second wall, or can at least a part of the conveying device for holding the workpiece at the edge of the workpiece extend into the space between the first wall and the second wall through the discharge opening? In the latter case, the portion for holding the workpiece can be effective in longitudinally moving the workpiece within the device. In the former case, the portion for holding the workpiece can at least support the workpiece when the workpiece moves within the device, and the portion for holding the workpiece can also move the workpiece within the device.

[0035] In one embodiment, each discharge opening has a height of at most 100 mm, for example, at most 50 mm or even less than 40 mm.

[0036] In this context, the term height refers to the dimension across the central plane.

[0037] Due to the relatively low height, it becomes possible to achieve the effect of returning the section of the workpiece to the central plane when it moves away from the central plane at a flow rate of at most 10 m / s, for example, less than 8 m / s or even less than 5 m / s. The minimum flow rate can be, for example, 0.1 m / s or 0.5 m / s.

[0038] One embodiment further comprises at least one liquid-permeable electrode, for example a flat electrode, extending in a plane between the central plane and one of the first wall and the second wall.

[0039] This embodiment is for an electroplating cell. In particular, there may be a first liquid-permeable electrode, for example a first flat electrode, extending in a plane between a central plane and a first wall, and a second liquid-permeable electrode, for example a flat electrode, extending in a plane between the central plane and a second wall. Even for a relatively thin workpiece, the risk of getting too close to one or more electrodes due to undulations is relatively low. This reduces the risk of damage due to physical contact and ensures that the plating thickness is uniform. In one embodiment, the electrode can comprise a mesh. Each electrode can be subdivided into electrically insulated segments from each other located in the plane of the electrode. Examples of such a configuration and its effects are described, for example, in WO 2003 / 018878.

[0040] One embodiment further comprises at least one liquid-permeable shielding structure, for example a flat shielding structure, extending in a plane between the central plane and one of the first and second walls.

[0041] In one embodiment, such a shielding structure is provided on each side of the central plane. When electrodes are provided on each side of the plane, the shielding structure is positioned between the central plane and the electrodes. Thus, contact between the surface of the workpiece and the electrodes is prevented under all circumstances. Otherwise, since one of the workpiece and the electrodes generally forms an anode and the other forms a cathode, such contact would lead to a short circuit. Each shielding structure generally has a solid structure that is closest to the central plane on the side of the central plane where the shielding structure is provided. Each shielding structure can be made of an electrically insulating material, such as a polymer material. One way to implement the shielding structure is to provide a relatively large number of relatively small diameter through-holes in a plate of the electrically insulating material. The areal density of such through-holes is at least one order of magnitude greater than the areal density of the openings in the first and second walls. The diameter of the through-holes accordingly becomes smaller. To achieve a uniform current density, two or more adjacent through-holes at a particular location can be connected by removing the material that would otherwise separate them. Alternatively or additionally, one or more through-holes may be blocked. In one example, in a device intended for use with a workpiece having a thickness of less than 1 mm, such as less than 100 μm or even less than 50 μm, the distance between the central plane and the shielding structure is between 2 mm and 15 mm, such as less than 10 mm or even less than 8 mm. One or more shielding structures are particularly useful when processing separate flat workpieces (i.e., sheets rather than continuous webs), since the workpiece enters the cell at a free edge where it is essentially unsupported. The section of the workpiece at that edge may curve in the direction of movement.

[0042] In one embodiment of the device, nozzles extending into the openings are provided in the first and second walls.

[0043] Generally, each nozzle is provided at each opening. The nozzle may be formed in the wall or the nozzle may be a separate device inserted into a hole in the wall and fixed in a predetermined position relative to the wall. Generally, the opening corresponds to the exit orifice of the nozzle. However, in one embodiment, the exit orifice of the nozzle device can be recessed somewhat relative to the opening formed in the surface of the wall. The nozzle devices may project slightly from the holes in which they are located. However, separate nozzle devices completely fill the holes in the wall into which they are inserted. Thus, when separate nozzle devices are provided, the liquid cannot bypass these nozzle devices inserted through the first wall and the second wall. The nozzle makes it possible to shape the flow of the liquid entering the space. This is because the nozzle is different from a cylindrical passage.

[0044] In a specific example of this embodiment, the orifice of the nozzle has an elongated shape having a dimension larger in the second direction than in the first direction.

[0045] This has the effect of providing the necessary tangential flow field (from the center towards the discharge openings along the surface of the workpiece) without the need to extremely reduce the mutual spacing between the openings, especially in the first direction. A relatively uniform coating of the workpiece surface by the liquid is achieved. The nozzle may be, for example, a fan nozzle, i.e., a nozzle with a slit-shaped orifice. In a specific example of this embodiment, the device also comprises at least one liquid-permeable electrode, for example a flat electrode, extending in a plane between the central plane and one of the first wall and the second wall, and the electrodes are provided with elongated liquid-permeable windows, for example openings, aligned with the respective nozzle orifices. In this embodiment, the liquid-permeable windows in the electrodes can have a relatively small area. Since the electrodes are non-conductive at the locations where the windows are provided, fewer compensation means are required to account for the non-conductive windows. In particular, when a shielding structure is also provided between the electrode and the central plane, less adaptation of the shielding structure is required to achieve a uniform current density over the region of the workpiece.

[0046] In one embodiment of the device, the openings are aligned as rows extending at least substantially in the second direction.

[0047] This contributes to providing a uniform flow from the center to the discharge openings. Generally, there are at least 3, for example at least 5 or at least 10, openings in each row. Since the openings are aligned, each row extends linearly. Since the openings are aligned as rows extending basically in the second direction (within normal manufacturing tolerances), the rows extend parallel to each other.

[0048] In an example of an embodiment where the openings are aligned as rows extending at least substantially in the second direction, the openings are uniformly distributed within each row.

[0049] That is, the spacing between the apertures is at least approximately the same for all apertures in a row, and there are at least three apertures in each row, hi one embodiment, the spacing is the same for a number, such as a majority, of the rows.

[0050] In a particular example of an embodiment in which the apertures are aligned in rows extending at least approximately in the second direction and the apertures are uniformly distributed within each row, the apertures in each row are offset in the second direction relative to the apertures in at least one other row.

[0051] This helps to avoid streaks in the first direction in which the workpiece is subjected to electrochemical processing.

[0052] In a particular example of an embodiment in which the apertures are aligned in rows extending at least approximately in the second direction, the apertures are uniformly distributed within each row, and the apertures in each row are offset in the second direction relative to the apertures in at least one other row, the apertures are aligned in columns extending at an acute angle to the first direction.

[0053] Thus, a compromise is achieved between establishing a substantially uniform flow field and preventing streaks on the workpiece.

[0054] In one embodiment of the device, the first wall and the second wall are: (i) 1 m 2 and (ii) a linear density in a second direction (x) of at least 16 openings per meter.

[0055] One advantage is that it allows relatively thin discrete workpieces (i.e., sheets rather than continuous webs) having thicknesses on the order of 1-100 μm, e.g., 5-50 μm, to be processed while maintaining a relatively good central plane, particularly in devices where the central plane (here the transport plane) is configured to be a substantially horizontal plane.

[0056] In the case of a device configured for use in an apparatus where the central plane is a plane that is substantially perpendicular, the first wall and the second wall can have openings in at least one of (i) a surface density of at least 230 openings per square meter and (ii) a linear density of at least 8 openings per meter in a second direction (x). Reducing the number of openings reduces the manufacturing cost of the device. When the central plane, i.e., the transport plane, is a plane that is substantially perpendicular, gravity helps to return the section of the workpiece that has moved out of the plane back into the plane. Therefore, fewer openings are required for a workpiece of a given thickness. 2 In another aspect, according to the present invention, an apparatus for wet treating a flat workpiece comprises at least one device according to any one of the preceding claims.

[0057] In another aspect, an apparatus for wet treating a flat workpiece according to the present invention comprises at least one device according to any one of claims 1 to 10.

[0058] The apparatus comprises one or more cells. At least one cell comprises one or more devices according to the present invention. The type of treatment to be carried out can be varied between cells.

[0059] The apparatus can include at least one pump for pumping liquid to the openings of the device according to the present invention or to the openings of each device. Thus, the pump functions as a source of pressurized liquid. The apparatus can be configured to drive the pump or each pump so as to achieve a specific minimum flow rate at the discharge opening of the device or at the discharge openings of each device.

[0060] In an embodiment of an apparatus where at least one of the discharge openings of the device is formed by a single gap extending between opposing liquid-impermeable portions, for example between the edge of the first wall and the edge of the second wall, along a range in a first direction of the space between the surfaces, the apparatus further comprises a transport device comprising at least one clamp that detachably engages the workpiece at the edge of the workpiece and is guided to move along the length of the gap, and at least one drive device for moving the transport device.

[0061] Thus, to move the workpiece through the device, it is only necessary for the workpiece to be contacted at one or both of its side edges. The device can, in one embodiment, include a series of two or more devices of the aforementioned kind and a single transport device for moving the workpiece throughout the series of devices. The transport device is guided to move in a first direction.

[0062] According to another aspect, a method of operating a device according to the present invention includes pumping a liquid through the openings and the discharge opening while moving the workpiece through the device in a central plane.

[0063] While the workpiece is moving through the device, the workpiece is held substantially in the central plane by the action of the liquid flowing along the surface of the workpiece. In particular, the liquid is pumped at a sufficient rate to ensure that any section of the workpiece moving towards one of the first and second walls from the central plane creates a local force tending to return that section towards the central plane. The workpiece is a separate workpiece, i.e., a sheet rather than a continuous web or a semi - continuous web. The workpiece is generally a panel or a foil.

[0064] According to another aspect, the present invention provides for the use of a device and / or an apparatus according to the present invention for manufacturing semiconductor devices, such as optoelectronic devices.

[0065] The device and / or apparatus can, in particular, be used for manufacturing photovoltaic devices. Such devices can be flexible devices. The device and / or apparatus can be used, for example, for manufacturing interconnects in damascene electroplating processes and / or for filling at least one of trenches and vias, for example.

[0066] In certain embodiments, the device and / or apparatus is used to deposit one or more device layers or precursor layers on a substrate, such as on a silicon substrate, on a glass substrate coated with a transparent conductive oxide (TCO) such as tin oxide (e.g., fluorine-doped tin oxide FTO, indium tin oxide ITO), or on a molybdenum-coated stainless steel substrate. When the device and / or apparatus is used to deposit a device layer or precursor layer, the workpiece can then be subjected to further processing steps in a controlled atmosphere, such as annealing, laser scribing, photoresist patterning, etc. In this regard, the workpiece can be relatively thin, but it is useful that it can be a separate workpiece. A roll-to-roll process for depositing a device layer or a precursor layer for forming a device layer is not necessary.

[0067] Both the absorber layer (or their precursors) and the support layer can be deposited.

[0068] Photovoltaic devices that can be manufactured in this way include CdS / CdTe-based solar cell devices, solar cell devices incorporating a solar cell substrate as ZnTe, ZnSe, ZnS, ZnO, and solar cell devices based on a doped silicon surface with a plating base as indium-doped tin oxide. These examples and further examples are disclosed, for example, in European Patent No. 2709160. 2 Cu 2 ZnSnS 4 or CuInGaSe 2 or solar cell devices based on a doped silicon surface with a plating base as indium-doped tin oxide.

Brief Description of the Drawings

[0069] The present invention will be described in more detail with reference to the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

[0070] Description of Embodiment Device 1 for forming a part of a cell of an apparatus for wet treating a flat workpiece includes a first liquid distribution device 2a and a second liquid distribution device 2b.

[0071] In this specification, it is convenient to define a first direction y, also referred to herein as the longitudinal direction, and a second direction x, which is transverse to the longitudinal direction y and also referred to herein as the lateral direction (Figure 4). In use, the flat workpiece is guided in the first direction y (Figure 4) through a space 3 (Figure 1) between the liquid distribution devices 2a, 2b. The workpiece extends substantially in a central plane 4 (Figure 2) intermediate the first liquid distribution device 2a and the second liquid distribution device 2b. In this example, the central plane 4 is generally a horizontal plane.

[0072] In the illustrated example, device 1 is for forming a part of an electroplating cell. Thus, device 1 further includes a first anode 5a and a second anode 5b, and a first shielding structure 6a and a second shielding structure 6b.

[0073] The shielding structures 6a, 6b can comprise a grid made of an electrically insulating material such as a polymer material, for example. The shielding structures 6a, 6b are liquid permeable. The anodes 5a, 5b can be made of, for example, metal, mesh, or other conductive grid structures. Thus, the anodes 5a, 5b are also liquid permeable.

[0074] Although two anodes 5a, 5b are shown in the drawing, these anodes 5a, 5b do not need to extend beyond the scope of the space 3 in the first direction y. Instead, a series of anodes may exist successively in the first direction y on a single plane. Further, each anode 5a, 5b can be subdivided into segments that are electrically insulated from each other in the second direction x.

[0075] The conveying device 7 (FIG. 1) is only shown very schematically. The conveying device 7 includes a clamp 8 for holding a workpiece at one side edge of the conveying device 7. A plurality of such conveying devices 7 can be provided to hold the workpiece. The driving device 9 is arranged to move the conveying device 7 in the first direction. The driving device 9 can be, for example, an endless belt or an endless chain. In the electroplating process, the workpiece functions as a cathode. The clamp 8 or each clamp 8 is arranged to be in electrical contact with the workpiece to establish a voltage difference between the workpiece and the anodes 5a, 5b.

[0076] In the illustrated embodiment, the workpiece is held only at one edge. In other embodiments, the workpiece can be held at both of the opposing edges as viewed in the second direction x. In particular, the workpiece can extend in the second direction x beyond the space 3 and be driven by wheels or belts that contact the workpiece at the edges of the workpiece.

[0077] Each of the liquid distribution devices 2a, 2b includes a housing having liquid inlets 10a, 10b for connecting to respective liquid supply conduits 11a, 11b. One or more pumps (not shown) are provided to pump liquid through the liquid supply conduits 11a, 11b.

[0078] The chambers 12a, 12b are defined by the housing. Each composite wall 13a, 13b comprises respective housing walls 14a, 14b of each housing and further walls 15a, 15b arranged on the housing walls 14a, 14b. At least the opposing surfaces of the walls 13a, 13b are substantially parallel to the central plane 4, as is the case with the anodes 5a, 5b and the shielding structures 6a, 6b. The component walls 14, 15 of each composite wall 13a, 13b can be made from different materials to one another. For example, the further walls 15a, 15b can be made from an electrically insulating material. The housing walls 14a, 14b can be made from a mechanically strong material. In an alternative embodiment, the further walls 15a, 15b are omitted. As long as the composite walls 13a, 13b form a barrier to the flow of liquid from the central plane 4 towards the liquid distribution devices 2a, 2b, only one of the component walls 14, 15 of each composite wall 13a, 13b needs to be impermeable to liquid.

[0079] Each chamber 12a, 12b is subdivided in a third direction z (FIGS. 1 and 2) transverse to the first direction y and the second direction x by inner walls 16a, 16b (FIG. 1). Each inner wall 16a, 16b is inclined with respect to the walls 13a, 13b between which the space 3 is defined therebetween. The liquid distribution spaces 17a, 17b are defined between the inner walls 16a, 16b and the walls 13a, 13b closest to the space 3. In one embodiment, the liquid distribution spaces 17a, 17b extend in the first direction y over substantially the entire extent of the walls 13a, 13b in the first direction y. In another embodiment, a plurality of adjacent liquid distribution spaces 17a, 17b are provided side by side in the first direction y, and each liquid distribution space 17a, 17b can extend in the second direction x from one side edge of the walls 13a, 13b to the opposite side edge.

[0080] The liquid distribution space 17 is closed at one side end and has an inlet at the opposite side end. The liquid distribution space 17 tapers such that the height of the liquid distribution space 17 decreases towards the closed end.

[0081] There is at least one gap 18a to 18f (Figs. 1 and 4) between the free ends of the inner walls 16a, 16b and the chamber side walls 19a, 19b. The at least one gap 18a to 18f all extend along the range of the chambers 12a, 12b in the first direction y. Each gap 18a to 18f provides liquid communication between the liquid distribution space 17 defined in the chambers 12a, 12b and the spreading liquid conduits 20a, 20b. The inlet sides of the spreading liquid conduits 20a, 20b are connected to the liquid inlets 10a, 10b. The outlet sides are located in the gaps 18a to 18f. In the illustrated embodiment, flow guides 21a to 21c (Fig. 3) are provided on the outlet side. The flow guides 21a to 21c subdivide the spreading liquid conduits 20a, 20b into parallel passages, in this example four passages. The side walls 22a, 22b of the spreading liquid conduit 20 are straight in the illustrated example, but can alternatively be curved.

[0082] Each of the walls 13a, 13b in which the space 3 between the liquid distribution devices 2a, 2b is arranged is provided with a plurality of passages 23a, 23b, 24a, 24b (Fig. 2) that terminate in openings for introducing liquid into the space 3.

[0083] In the illustrated embodiment, the passages 23a, 23b, 24a, 24b are oriented such that their longitudinal axes are substantially perpendicular to the central plane 4.

[0084] In the illustrated embodiment, the further walls 15a, 15b are support walls made of, for example, plastic. The further walls 15a, 15b into which the nozzle devices 25a to 25d (Fig. 2) are inserted are provided with threaded through-holes. Alternatively, the nozzle devices 25a to 25d can be press-fitted into the through-holes. The nozzle devices 25a to 25d completely block the through-holes so that liquid can only pass through the further walls 15a, 15b through the nozzle devices 25a to 25d. Thus, each section of the passages 23a, 23b, 24a, 24b is defined by one of the nozzle devices 25a to 25d.

[0085] The nozzle devices 25a to 25d are fan nozzle devices 25a to 25d that shape the flow of the liquid emerging from each of the nozzle devices 25a to 25d. For this purpose, the constriction forms an orifice 26 (FIG. 3) having an elongated shape with a dimension larger in the second direction x than in the first direction y. The same applies to the outlet opening 27 through which the liquid enters the space 3. This outlet opening 27 is slit-shaped in the illustrated embodiment.

[0086] The gaps 28a, 28b are defined between the walls 13a, 13b at the side edges of the walls 13a, 13b. These gaps 28a, 28b each extend in the first direction y substantially along the extent of the walls 13a, 13b.

[0087] Accordingly, during use, the liquid flows outward from the middle in the second direction x. The liquid distribution space 17 and the spreading liquid conduit 20 ensure that the liquid is introduced into the space 3 at a relatively uniform velocity, so that as a result, the flow accelerates towards the side edges of the workpiece. As a result, a self-centering effect is achieved and the workpiece is maintained in the central plane without the need for a support portion that contacts the workpiece. Nevertheless, the shielding structures 6a, 6b ensure that contact with the anodes 5a, 5b is prevented under all circumstances.

[0088] An example of the device 1 is configured for workpieces having a thickness of up to 100 μm, for example up to 60 μm, up to 50 μm, or even up to 10 μm. Typical dimensions of the height of the gaps 28a, 28b are in the range of 2 to 50 mm. The liquid is pumped at a velocity such that the velocity in the gaps 28a, 28b is at least 0.1 m / s, for example at least 0.5 m / s. The velocity is generally less than 10 m / s and may be less than 5 m / s.

[0089] The shielding structures 6a, 6b are spaced apart by at least 5 mm, at most 25 mm, for example at most 20 mm, or even less than 15 mm (in a direction perpendicular to the central plane 4). The distance from each anode 5a, 5b to the central plane 4 is at least 8 mm, for example at least 10 mm, and generally at most 15 mm, for example at most 12 mm.

[0090] In the illustrated embodiment, the nozzle devices 25a to 25d are arranged as rows extending substantially parallel to the second direction x. The mutual spacing between the openings, and thus between the nozzle devices 25a to 25d, is equal within each row. In the illustrated embodiment, this spacing is also the same for all rows. However, the nozzle devices 25a to 25d of each successive row in the first direction y are offset in the second direction x with respect to the nozzle devices 25a to 25d of the previous row. The offset is the same for each pair of rows, and the spacing between the rows in the first direction y is also uniform. As a result, it can be said that the nozzle devices 25a to 25d are arranged in a row at a slight angle α with respect to the first direction y (Figure 3). A further result is that the number of nozzle devices 25a to 25d can be 10 or 11. The spacing is such as to achieve a linear density of at least 16 openings 27 per meter in the second direction x. In the illustrated embodiment, the areal density is at least 460 per square meter, for example at least 600 per square meter. Thus, the dimensions of the walls 13a, 13b in the first direction y are at most 500 mm, for example 400 - 450 mm. The dimensions in the second direction x are at most 700 mm, for example 600 - 650 mm. With these dimensions, there are at least 120 openings 27 for each of the walls 13a, 13b. 2 per square meter, for example at least 600 2 per square meter. Thus, the dimensions of the walls 13a, 13b in the first direction y are at most 500 mm, for example 400 - 450 mm. The dimensions in the second direction x are at most 700 mm, for example 600 - 650 mm. With these dimensions, there are at least 120 openings 27 for each of the walls 13a, 13b.

[0091] The present invention is not limited to the above-described embodiments and can be modified within the scope of the appended claims. For example, although the device in this example has a horizontal transport plane (referred to as the central plane 4 in this specification), a device having a vertical transport plane can also achieve the same effect. In such a device, the flow field described in this specification can be realized by immersing the device 1 relatively deeply in the tank so that the liquid emerging from above one of the gaps 28a, 28b does not spout into the free space. In an embodiment having a vertical transport plane, the dimension in the first direction x may be larger, for example, up to 1300 mm at most. The minimum number of nozzle devices 25a to 25d per unit area and the minimum linear density in the second direction x can be set to approximately half of the values given above for the embodiment having a horizontal transport plane without sacrificing the effect of holding the workpiece relatively well within the central plane.

[0092] In a device including a plurality of devices 1 arranged in series, the interval between the shielding structures 6a, 6b may decrease in the first direction y.

[0093] As long as the liquid can flow through, the space accessible to the liquid does not have to be completely empty. Therefore, the section of that space can be filled with a porous structure, such as a foam. This can function as a spacer, for example, between the walls 13a, 13b and the anodes 5a, 5b and / or between the anodes 5a, 5b and the shielding structures 6a, 6b.

Description of Reference Numerals

[0094] 1 Device 2a, 2b Liquid distribution device 3 Space 4 Central plane 5a, 5b Anode 6a, 6b Shielding structure 7 Conveying device 8 Clamp 9 Driving device 10a, 10b Liquid inlet 11a, 11b Liquid supply conduit Chambers 12a, 12b First composite wall 13a and second composite wall 13b Housing walls 14a, 14b Additional walls 15a, 15b Inner walls 16a, 16b Liquid distribution spaces 17a, 17b Clearances within the chambers 18a to 18f Chamber side walls 19a, 19b Expanded liquid conduits 20a, 20b Flow guides 21a to 21c Expanded conduit side walls 22a, 22b First passageways 23a, 23b Second passageways 24a, 24b Nozzle devices 25a to 25b Orifice 26 Outlet opening 27 Clearances 28a, 28b

Claims

1. A device for a cell of an apparatus for wet treating a flat workpiece, comprising: a structure having a first wall (13a) and a second wall (13b); the workpiece being movable in a first direction (y) within a central plane (4) through a space (3) between the first wall (13a) and the second wall (13b); openings (27) for introducing a pressurized liquid between the first wall (13a) and the second wall (13b) are provided facing the central plane (4) on opposite sides of the central plane (4); the openings (27) are distributed in the first direction (y) and in a second direction (x) transverse to the first direction (y); discharge openings (28a, 28b) for the liquid to exit the space (3) are defined on opposite sides of the space (3) as seen in the second direction (x) along the extent of the space (3) in the first direction (y); the first wall (13a) and the second wall (13b) form a barrier against the flow of liquid from the space in a direction (z) perpendicular to the central plane (4); in the device, passages (23a, 23b, 24a, 24b) are provided through the walls (13a, 13b), each passage (23a, 23b, 24a, 24b) being arranged to conduct the liquid to one of the respective openings (27); the device comprises a first liquid distribution device (2a) and a second liquid distribution device (2b), the first wall (13a) and the second wall (13b) comprising a wall (14a) of the first liquid distribution device (2a) and a wall (14b) of the second liquid distribution device (2b) respectively; the first liquid distribution device (2a) and the second liquid distribution device (2b) are mounted such that the space (3) extends between the liquid distribution devices (2a, 2b); A device, characterized in that.

2. The device according to claim 1, wherein the openings (27) are defined on the surfaces of the first wall (13a) and the second wall (13b) at the ends of the respective passages (23a, 23b, 24a, 24b).

3. At least one liquid distribution space (17a, 17b) extending in the second direction (x) across the inlet of the passageways (23a, 23b, 24a, 24b) is defined on the side of at least one of the first wall (13a) and the second wall (13b) opposite to the space (3), for the device according to claim 1 or 2.

4. The liquid distribution space (17a, 17b) is delimited by barriers (16a, 16b) inclined with respect to the walls (13a, 13b) such that the liquid distribution space (17a, 17b) tapers towards the edges of the walls (13a, 13b), for the device according to claim 3.

5. At least one expanding liquid conduit (20a, 20b) having an inlet (10a, 10b) connectable to the liquid supply conduits (11a, 11b) on one side and widening towards the opposite side in liquid communication with the liquid distribution space (17a, 17b) at a plurality of locations along the width of the expanding liquid conduit (20a, 20b), comprising at least one expanding liquid conduit (20a, 20b), for the device according to claim 3 or 4.

6. The expanding liquid conduit (20a, 20b) and the liquid distribution space (17a, 17b) are defined within a chamber (12a, 12b) within the housing of one of the first liquid distribution device (2a) and the second liquid distribution device (2b) by barriers (16a, 16b) extending within the chamber (12a, 12b), for the device according to claim 5.

7. At least one of the discharge openings (28a, 28b) is formed by a single gap extending along the extent of the first direction (y) of the space (3) between mutually facing liquid-impermeable portions, for the device according to any one of claims 1 to 6.

8. Further comprising at least one liquid-permeable electrode (5a, 5b) and / or at least one liquid-permeable shielding structure (6a, 6b) extending in a plane between the central plane (4) and one of the first wall (13a) and the second wall (13b), for the device according to any one of claims 1 to 7.

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