EP4073287A1

EP4073287A1 - Apparatus for electroless metallization of a target surface of at least one workpiece, and method and diffuser plate for the purpose

Info

Publication number: EP4073287A1
Application number: EP20810922.3A
Authority: EP
Inventors: Hubert PARZEFALL
Original assignee: Ap&s International GmbH
Current assignee: Ap&s International GmbH
Priority date: 2019-12-12
Filing date: 2020-11-18
Publication date: 2022-10-19
Also published as: US20230047104A1; CN114829673A; CN114829673B; WO2021115746A1; DE102019134116A1

Abstract

The present invention relates to an apparatus (1) for electroless metallization of a target surface of at least one workpiece (5), having a vessel (10) to accommodate a metallizing solution having an inlet (15) and an outlet (16) for the metallizing solution, and a holder (20) which is for accommodating the at least one workpiece (5) and can be arranged within the vessel (10), wherein at least one diffuser plate (30) is provided between the at least one inlet (15) and the holder (20) and has a multitude of diffuser openings (35) spaced apart in the plane of a plate (E), and wherein a movement device (40) is provided, which can move the diffuser plate (30) in at least one spatial direction in the vessel (10). The present invention further relates to a process for electroless metallization of the target surface of the at least one workpiece (5).

Description

Device for electroless plating of a target surface of at least one workpiece and method and diffuser plate for this

The present invention relates to a device for electroless plating of a target surface of at least one workpiece to improve the homogeneity of a deposited metal layer of a workpiece with the features of patent claim 1, a method for electroless plating of at least one workpiece with the features of claim 13 and a Diffuser plate with the features of claim 16.

Devices and methods for electroless plating of a target surface of at least one workpiece are previously known from the prior art in different configurations. Electroless metal deposition from an electrolyte solution is generally known in semiconductor, solar or nano technology. The electroless metallization of objects, for example structured wafers, has clear advantages over galvanic metallization in terms of stability and the homogeneity and conformity of the deposition technology and properties of the layers that can be achieved. It is advantageous that no devices for electrical contacting are necessary for the workpieces to be coated. It is also possible to metallize several workpieces at the same time in a so-called batch process, which significantly increases the productivity of such devices. It can also be mentioned as an advantage that the purely chemical deposition process means that no seed layer has to be provided on the workpiece. The process of electroless deposition of a metal intent requires a plating solution with a reducing agent, a metal source and a complexing agent, whereby - in addition to the control of the solution composition - parameters such as the pH value, the temperature and the composition of the metal plating solution with high Accuracy must be set, since the active initiation of a chemical reaction by means of a catalyst is extremely sensitive to the process temperature. The reactions can take place both autocatalytically and as an exchange or displacement reaction.

Typically, the operating temperature of the electroless plating electrolyte solution may be in an area close to the Autokatalyse- temperature for a spontaneous _self-Z replacing the metallization are approximate solution. The occurrence of self-initiated decomposition of the electroless plating solution leads to metal deposition not only on desired areas of the target surfaces of the workpieces, but also on surfaces of the plating system, such as the reactor cell, the electrolyte solution container, the supply lines and the like. In pronounced cases of self-initiated disintegration, essentially the entire metal content of the electrolyte is rapidly reduced to pure metal, which could possibly clog all lines, tubes and the process basin.

As a result, great effort is required to chemically remove the metal lisierungslösung with, for example, nitric acid and other chemicals, at the same time all the expensive electrolyte components are lost. In addition, toxic waste must also be disposed of as possible, which will also contribute significantly to the operating costs of a device for electroless plating. The devices for electroless plating known from the prior art are not designed as single-wafer systems, but rather for batch processes, in order to increase the achievable principle. In order to be able to process a plurality of wafers at the same time, these are placed in holders, so-called carriers, in a basin in which the electrolyte solution is. The wafers are typically upright in the holders, with the electrolyte solution in the basin being converted permanently in order to ensure an even distribution of the reactants.

Typically, the electrolyte solution is introduced into the basin from below via a central inlet and can be removed from the top and fed to the circulation and heating. The withdrawal can be realized, for example, via a simple overflow into an overflow basin.

In the devices known from the prior art, the inlet for the electrolyte solution is arranged in the bottom of the container, the inlet being designed as a single inlet nozzle with an additional diffuser plate. This diffuser plate has flow-optimized inlet openings in the form of concentric circles.

In the present prior art, it has proven to be disadvantageous that the layer thickness of the deposited metal varies over a wafer and there are also differences from wafer to wafer within a batch. These differences are justified on the one hand with a variation in the surface potential of the circuits on the wafer and with the hydrodynamic conditions in the process container, which increases the concentration of the reactants in the electrolyte solution varies over the surface of the target surfaces to be metallized. It has also been shown in this prior art that the inlet openings of the diffuser plates are blocked or throttled by gas bubbles.

This is where the present invention begins.

The present invention is dedicated to the task of proposing an improved device for electroless plating of workpieces, which expediently eliminates the disadvantages of the devices known from the prior art, which enables uniform layer deposition within a wafer and from wafer to wafer .

This object is achieved by a device for electroless metalization of at least one workpiece with the features of claim 1, by a method with the features of claim 13 and a diffuser plate with the features of claim 16.

Further advantageous refinements of the present invention are specified in the subclaims.

The inventive device for electroless plating of a target surface of at least one workpiece with the features of claim 1 has a container for receiving a plating solution with an inlet for the plating solution and an outlet for the plating solution. In addition, the device according to the invention has a holder for receiving the at least one workpiece, which can be arranged in the container. According to the invention it is provided that at least one diffuser plate is provided which has a plurality of spaced apart in a plate plane Has diffuser openings, and wherein a movement device is provided which can move the diffuser plate in at least egg ner spatial direction in the container.

The invention is based on the idea that a movement is coupled into the reaction process through the movement of the diffuser plate, which reduces the depletion of the metallization solution on its way from the inlet to the outlet and thus increases the homogeneity and conformity of the Metallab separation can be. The movement of the diffuser plate can cause additional circulation of the metallization solution in the container. The movement of the diffuser plate also prevents gas bubbles from possibly getting stuck in the area of the diffuser openings of the diffuser plate, as a result of which diffuser openings are blocked. Due to the improved circulation, an improved transport of the reactants on the target surface of the workpiece can be achieved.

The inlet can advantageously be arranged on the bottom and / or the outlet on the top. Several inlets and / or outlets can also be provided. In particular, several inlets on the container can be arranged at a distance from one another in order to supply the metallization solution in several places.

A further advantageous embodiment of the present invention provides that the diffuser plate is net angeord between the at least one inlet of the container and the holder. By arranging the diffuser plate in this way, the metallization solution flowing into the container from the inlet is mixed and homogeneously distributed before the measurement metalization solution can flow through the diffuser openings of the diffuser plate in the direction of the at least one workpiece.

It has also proven to be advantageous if the movement device can move the diffuser plate in at least one recurring or cyclical movement in and against one of the spatial directions perpendicular to the plate plane. The diffuser plate is thus raised and lowered by the movement device, whereby the metallization solution is forced through the diffuser opening when the diffuser plate is lowered. As a result of this forced flow, so-called "jets" or rapids are formed on the side of the diffuser plate facing the outlet through the diffuser openings. On the other hand, when the diffuser plate is raised, backflows are generated. The repeated formation of jets and backflows results in local impoverishment the metallization solution is reduced on its way from the inlet to the outlet and the homogeneity and conformity of the metal deposition are increased.

Another advantageous embodiment of the present invention provides that the receptacle is movable in the container. In particular, it is preferred if the receptacle is movably arranged in the container in such a way that the receptacle follows the movement of the diffuser plate. The coupling of the movement of the diffuser plate and the receptacle prevents the distance between the diffuser plate and the receptacle from being increased or decreased during the movement of the diffuser plate, whereby the effect of the movement and the flushing of the metallization solution through the jets formed does its work to miss. Furthermore, in accordance with the present invention, it can be provided that the receptacle is arranged in a fixed position in the container during the electroless plating. In other words, the receptacle is not moved in the case of agitation of the diffuser plate in the container. It has been shown that this means that the metallization solution on the target surface is effectively exchanged and updated. The uniformity of the layer is improved and makes handling easier, since the fixed arrangement of the receptacle in the container reduces the stress on the workpieces or wafers.

Furthermore, it is advantageous if the receptacle can be moved in the container by the moving device of the diffuser plate or by a further moving device. In particular, it is preferred if the receptacle is moved in at least two spatial directions by the movement device in the container. This movement is also referred to as agitation, the agitation in at least two spatial directions enabling improved transport of the reactants on the target surface of the workpiece.

According to a further preferred embodiment of the present invention, the diffuser openings have a first cross-sectional area on a first side and a second cross-sectional area on a second side opposite the first side, the first cross-sectional area being larger than the second cross-sectional area. In particular, it is particularly preferred if the first side of the diffuser plate with the larger cross-sectional area is arranged in the container on the side facing the inlet and the second side of the diffuser plate on the side facing the receptacle. The diffuser openings can preferably be conical or ke- be designed in gel form with a cone section in order to minimize pressure losses and, depending on the flow direction either as a nozzle or diffuser, accelerate or delay the metallization solution and improve the flow. Pronounced "jets" are formed through the nozzle, which on the one hand increase the degree of turbulence of the metallization solution in the basin and on the other hand can penetrate far into a space between two adjacent workpieces in the receptacle.

In particular, it has proven to be advantageous if the ratio between the first cross-sectional area and the second cross-sectional area is at least 1.1, the ratio being preferably selected to be greater than 1.1, for example 1.5 or even more preferably 2 or more .

Furthermore, it has proven to be advantageous if the diffuser openings are arranged perpendicular to the plate plane of the diffuser plate. Due to the perpendicular arrangement of the diffuser openings to the plane of the plate, the jets can also _{penetrate into areas in the container V} that are far away from the diffuser plate.

A further advantageous embodiment of the present invention provides that the diffuser openings are arranged in rows in the plane of the plate, and that adjacent rows are arranged offset from one another. In particular, it has proven to be advantageous if the diffuser openings in the respective row are equidistantly arranged at a first distance, and the offset between two adjacent rows corresponds to approximately half of the first distance. Furthermore, it has also proven to be advantageous if the second distance between two adjacent rows is smaller than the first Distance, whereby a high density of diffuser openings can be realized. The rows can be arranged along a straight line or alternatively along one or more concentric circles. It should be noted that the arrangement of the diffuser openings in the plane of the plate can also be based on other criteria. For example, the arrangement of the diffuser openings in the plane of the plate can be predetermined by the at least one workpiece and / or the receptacle.

It has proven to be advantageous if the holder can accommodate several workpieces in rows, each spaced apart by an intermediate space, and / or that the diffuser openings are arranged in such a way that they are aligned with the intermediate space or are directed into the intermediate space. The jets formed by the diffuser plate can therefore flow particularly well around the workpieces without hitting an obstacle, and concentration depletions are also counteracted in the places remote from the diffuser plate.

In addition, it has proven to be advantageous if the diffuser plate corresponds to the shape of the container. In particular, it is preferred if the diffuser plate kolbenar tig is held movably Lich mounted with a running gap on a wall of the container. The diffuser plate consequently divides the container into a first area into which the at least one inlet opens, and a second area in which the holder can be arranged and has the outlet. The gap arranged between the diffuser plate and the container is preferably made as small as possible in order to ensure that the metallization solution is forced completely through the diffuser openings of the diffuser plate. However, when dimensioning the gap, it should be taken into account that the gap is to avoid major pressure fluctuations in the first area is not too small, since such pressure fluctuations could damage both the container and the peripherals such as lines, pumps or the like. A gap dimension of the gap can be a multiple of the thickness of the diffuser plate.

It has also proven to be advantageous if the diffuser plate has a frame which protrudes from the plate plane of at least one of the sides of the diffuser plate. The frame is preferably arranged circumferentially on the side of the diffuser plate facing the gap and increases the effective length of the gap between the diffuser plate and the wall, as a result of which gap flows are reduced. The frame preferably has flow guide means through which the flow is guided in the direction of the diffuser openings when the diffuser plate is lowered.

Another aspect of the present invention relates to a method for electroless plating of a target surface of at least one workpiece with a previously presented device, having the following method steps:

- Inserting at least one workpiece into the receptacle;

- Positioning of the receptacle in the container filled with a metallizing solution, through the inlet of which the

Metallizing solution, preferably continuously, is fed into the container and through its drainage metallizing solution, preferably continuously, is discharged from the Behäl ter; - Rinsing around the at least one workpiece with the metallization solution by moving the diffuser plate rela tively to the container through the jets formed by the diffuser openings in the metallization solution.

The core idea of the method according to the invention is based on the fact that when the diffuser plate moves in the container, the metallization solution is forced through the diffuser openings to form jets. The jets flow through the metallization solution in the container as completely as possible, whereby a homogeneous distribution of the reactive electrolyte components and an accompanying more homogeneous layer deposition can be achieved. At the same time, the metalization solution is mixed on the side facing the inlet in the container, which avoids local excessive concentration and / or depletion of concentration and improves the homogeneity of the metal deposition over several workpieces in a batch process.

According to a further advantageous implementation of the method according to the invention, it is provided that the diffuser plate is moved cyclically by the movement device, and that alternately jets exit from the diffuser openings in the direction of the at least one workpiece or return flows enter the diffuser openings. During the movement of the diffuser plate gap _S can trömungen Zvi the diffuser plate and the wall of the container just rule if contribute to the mixing of the electrolyte solution.

Furthermore, it is advantageously provided that the holding tion is moved with the at least one workpiece in the container by the movement device, or that the holder with the at least one workpiece in the container by a further movement device is moved independently of the diffuser plate. It can be advantageous that the further movement device moves the holder with the at least one workpiece in the two spatial directions perpendicular to the direction of movement of the diffuser plate.

A further development of the method provides that the holder with the at least one workpiece in the container is held firmly in one position when the diffuser plate is moved in the container. The holder with the at least one workpiece can be positioned mechanically decoupled from the diffuser plate in the container filled with the metallizing solution and remain unchanged in this position until the intended metallization of the target surface of the workpiece has taken place and the holder has the least amount of egg Workpiece is removed from the container.

Furthermore, it is advantageous if the diffuser plate for the formation of jets formed by the diffuser openings is also moved by the movement device when no holder is positioned in the container. In this so-called standby mode, movement or agitation of the diffuser plate can lead to improved temperature control and temperature distribution in the container. In the event that a heater is provided in the container, the agitation of the diffuser plate flows around the heater both in production mode and in standby mode and the formation of bubbles on the heater or the heating elements is reduced.

A third aspect of the present invention relates to a diffuser plate for the device described above and for use in the method described above. An exemplary embodiment according to the invention of a device for electroless plating of a target surface we at least one workpiece and the associated method will be described in detail with reference to the accompanying drawings. Show it:

1 shows a simplified and schematic representation of a device according to the invention for electroless metallization of at least one workpiece having a container for receiving a metallization solution in which a diffuser plate is movably arranged,

FIG. 2 shows an enlarged and schematic representation of the diffuser plate according to FIG. 1, and

FIG. 3 shows a schematic detailed illustration of the diffuser plate according to FIGS. 1 and 2.

Identical or functionally identical parts are identified below with the same reference symbols. For the sake of clarity, not all parts that are the same or functionally the same are provided with a reference number in the individual figures.

Figure 1 shows a device 1 for electroless metallization of a target surface of at least one workpiece 5. Such workpieces are (not shown) wafers that are widely used as a substrate or base plate for electronic components, including for integrated circuits (IC), micromechanical components or photoelectric coatings . The device 1 consists essentially of a container 10 for receiving a metallization solution (not shown) into which the workpieces 5 for metallization can be immersed.

In the exemplary embodiment shown, a plurality of workpieces 5 is arranged in holders 20, which are designed as so-called wafer carriers, standing vertically.

The container 10 has a bottom side 11 and a top side 12, and is formed by a liquid-tight wall. While the top 12 is designed to be essentially open, the remaining sides are closed, as a result of which the container 10 can receive the metallization solution. The container 10 also has at least one inlet 15 and an outlet 16. Preferably, several inlets 15 can be easily seen, which are arranged in a distributed manner. More preferably, the inlet 15 or the inlets 15 can be arranged on the bottom side. The drain 16 is preferably arranged on the top side, the drain 16 being in the present case as an overflow 18 is staltet. The metalization solution can be continuously fed into the container 10 through the inlet 15, while the outlet 16 is designed for the preferably continuous discharge of the metalization solution, whereby the metalization solution flows through the container from the inlet 15 to the outlet 16. In order to collect the metallizing solution emerging through the overflow, the container 10 is arranged in an overflow container which surrounds the container 10. Like the container 10 itself, the overflow container is only shown schematically. In the container 10, a diffuser plate 30 can be arranged who the. The diffuser plate 30 can be an essentially flat plate which has a plate plane E which corresponds to the normal plane of the diffuser plate 30. The diffuser plate 30 has a first side 31 and a second side 32, the first side 31 facing the lower side 11 of the container 10 and the second side 32 facing the upper side 12 of the container 10.

The diffuser plate 30 is movably arranged in the container 10 and can preferably be raised and lowered in a direction parallel to a normal vector of the plate plane E, which preferably points in the vertical direction, between the bottom side 11 and the top 12. For this purpose, the shape of the diffuser plate 30 is adapted to the shape of the container 10 and a gap or a running gap is formed between the diffuser plate 30 and the container 10.

The diffuser plate 30 divides the container 10 into a first area 13 and a second area 14, the first area 13 enclosing a plenum between the bottom side 11 of the container 10 and the first side 31 of the diffuser plate 30 and the second area 14 enclosing the area of the Container 10 summarizes, which extends from the second side 32 of the diffuser plate 30 to the top 12.

In the first area 13 between the diffuser plate 30 and the inlet 15, a heater 42 can be arranged, which can be formed from egg ner plurality of heating elements, which can be fixedly arranged in the container 10 parallel to the diffuser plate 30. The heater 42 can regulate the temperature of the metalization solution in the container. As can be seen from FIGS. 2 and 3, the diffuser plate 30 has a multiplicity of diffuser openings 35. The respective diffuser opening 35 breaks through the diffuser plate 30 completely and connects the first side 31 to the second side 32.

The diffuser openings 35 can - as in the illustrated Ausfüh approximately example - be arranged in several rows, which are arranged paral lel and spaced from one another. In the respective row, the diffuser openings 35 are arranged at a first distance from Dl, preferably equidistantly along a straight line or in one or more concentric circles, spaced from one another. Adjacent rows run at a second distance D2. The second distance D2 is preferably smaller than the first distance D1 in order to achieve the highest possible density of diffuser openings 35 on the diffuser plate 30.

It can also be seen from FIGS. 2 and 3 that the diffuser openings 35 on the first side 31 and the second side 32 have different cross-sectional areas A1, A2. On the first side 31, the diffuser opening 35 has a first cross-sectional area Al and on the second side 32 the diffuser opening 35 has a second cross-sectional area A2, the first cross-sectional area Al preferably being larger than the second cross-sectional area A2. The diffuser opening 35 can thus have a conical section, through which the diffuser opening 35 has a cross-sectional tapering between the first side 31 and the second side 32.

On the first side 31 is a frame 34 from the plate plane E, which is formed circumferentially along the side edge of the diffuser plate 30. The frame 34 stands - as in Figure 2 is shown - free from the first side 31 in the direction of the bottom side 11 and can have a bevel formed as a flow guide center, which can be arranged on the side facing away from the gap and through which the area enclosed by the frame 34 is widened in the direction of the bottom side 11.

Furthermore, it can be seen from FIG. 2 that the diffuser plate 30 has holding means 36 through which the diffuser plate 30 can be immersed in the container 10 or in the metallization solution. The holding means 36 comprise fastening means 37 on the side facing away from the diffuser plate 30.

The holding means 36 enable the diffuser plate 30 to be immersed or lowered into the container 10, the holding means 36 preferably being designed in such a way that the fastening means 37 protrude from the top 12 of the container 10 when the diffuser plate 30 is lowered.

The device 1 also has a movement device 40, which is arranged laterally next to the basin 10 in FIG. The movement device 40 is connected to the fastening means 37 at the free end of the holding means 36 via an agitation frame 45. The movement device 40 can have any drive configuration that can generate a movement that can be transmitted to the diffuser plate 30 by means of the agitation frame 45, the fastening means 37 and the holding means 36.

Preferably, the moving device 40 can raise and lower the diffuser plate 30 in the container 10, the diffuser plate 30 being lowered in the direction of the diffuser plate 30 the bottom side 11 is moved and when lifting the diffuser plate 30 is moved in the direction of the top 12.

When the diffuser plate 30 is lowered, the metallization solution enclosed in the first loading area 13 is forced into the diffuser openings 35 and emerges on the second side 32 from the respective diffuser opening 35 in a rapids, a so-called "jet", which then flows into the second Area 14. When the diffuser plate 30 is raised, the metallization solution flows from the second area 14 in the direction of the first area 13, the backflowing metallization solution being mixed in the first area 13 with the metallization solution supplied through the inlet 15. The heater 42 is flowed around , whereby the formation of bubbles on the heater 42 can be reduced and a homogeneous temperature distribution can be realized.

The larger cross-sectional areas A1 of the diffuser openings 35 on the first side 31 lead the metallization solution nozzle-like in the direction of the second side 32, wherein when the diffuser plate 30 is lowered, gas bubbles are easily forced through the diffuser openings 35.

The movement device 40 can preferably raise and lower the diffuser plate 30 cyclically, whereby alternating jets and backflows are formed which flush through the second region 14 of the container 10 and the metalization solution located there is mixed. This counteracts a local depletion of the metallization solution in the second region 14.

The holder 20 can be immersed in the metalization solution in the container 10 through the open top 12. How As can be seen from FIG. 1, the holder 20 is positioned on the side of the diffuser plate 30 facing the top side 12 in the metallization solution in the container 10.

The holder 20 with the at least one workpiece 5 can be arranged on the side of the diffuser plate 30 facing the top 12 and positions the at least one workpiece 5 such that the workpiece 5 is washed around by the jets formed by the movement of the diffuser plate 30.

The holder 20 can follow a lowering and raising of the diffuser plate 30, which is why the distance between the at least one workpiece 5 and the diffuser plate 30 is constant during the electroless plating of the workpiece 5. Alternatively, the holder 20 in the container 10 can be arranged stationary and the distance between the diffuser plate 30 and the holder 20 is variable.

For electroless plating of a target surface of the at least one workpiece 5, the at least one workpiece 5 is first inserted into the holder 20. After inserting the at least one workpiece 5 in the holder 20, the holder 20 is positioned in the container 10 filled with a metallization solution, so that the workpieces 5 or the target surfaces of the workpieces 5 are completely lowered or completely penetrated in the metallization solution the metallization solution has been washed around. As soon as the holder 20 is completely lowered into the metallization solution in the container 10, the at least one workpiece 5 with the metallization solution is washed around by moving the diffuser plate 30 by means of the moving device 40 through the jets formed by the diffusor openings 35. It is still before geous if while moving the diffuser plate 30 the Metallizing solution is fed continuously through the inlet 15 into the container 10 and is likewise discharged through the outlet 16. The flow rate through the inlet 15 is preferably approx. 5-201 / min.

The diffuser plate 30 is preferably raised and lowered cyclically by the moving device 40, as a result of which jets emerge from the diffuser openings 35 again. The raising and lowering can be described as a sinusoidal or cyclical movement with approximately 20 periods, the amplitude or the stroke of the diffuser plate 30 being approximately 30mm. The jets mix the metallization solution in the second area 14 of the container 10 with the at least one workpiece 5, whereby a mixing of the metallization solution in this second area 14 counteracts a local depletion of the reactants of the metallization solution and the uniformity or layer thickness distribution on the target surface is improved.

List of reference symbols

1 device

5 workpiece

10 containers

11 floor area

12 top area

13 first area

14 second area

15 inlet

16 Drain 18 Overflow 20 Bracket

30 diffuser plate

31 first page

32 second page

34 frames

35 diffuser opening

36 holding means

37 Fasteners 40 Movement device 42 Heater 45 Agitation frame

E plate level

Claims

1. Device (1) for electroless plating of a target surface of at least one workpiece (5), comprising:

- A container (10) for receiving a metallization solution with an inlet (15) and an outlet (16) for the metallization solution, and

- A holder (20) for receiving the at least one workpiece (5), which can be arranged in the container (10),

- At least one diffuser plate (30) being provided between the at least one inlet (15) and the holder (20), which has a plurality of diffuser openings (35) spaced apart in a plate plane (E), and

- A movement device (40) being provided which can move the diffuser plate (30) in at least one spatial direction in the container (10).

2. Device (1) according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the moving device (40) can move the diffuser plate (30) in at least one recurring movement in one of the spatial directions perpendicular to the plate plane (E).

3. Device (1) according to claim 1 or 2, characterized in that the receptacle (20) in the container (10) is movable.

4. Device (1) according to one of claims 1 to 3, characterized in that the holder (20) by the movement device (40) or a further movement device in the container (10) is movable, or that the holder (20) posi tion fixed can be arranged in the container (10).

5. Device (1) according to one of the preceding claims, characterized in that a first cross-sectional area (Al) of the diffuser opening (35) on a first side (31) of the diffuser plate (30) is larger than a second cross-sectional area (A2) one of the second side (32) opposite the first side (31).

6. Device (1) according to claim 5, d a d u r c h g e k e n n z e i c h n e t that a ratio between the first cross-sectional area (Al) and the second cross-sectional area (A2) is at least 1.1, so A1 / A2> 1.1.

7. Device (1) according to one of the preceding claims, d a d u c h g e k e n n z e i c h n e t that the diffuser openings (35) are aligned in the at least one spatial direction.

8. Device according to one of the preceding claims, characterized in that the diffuser openings (35) are arranged in rows in the plate plane (E) and that adjacent rows are arranged offset from one another.

9. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the holder (20) can accommodate several workpieces (5) in rows spaced by gaps, and / o that the diffuser openings (30) are directed towards or into the gaps.

10. Device (1) according to one of the preceding claims, d a d u c h g e k e n n z e i c h n e t that the diffuser plate (30) corresponds to the shape of the container (10).

11. Device (1) according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the diffuser plate (30) has a frame (34) which protrudes from the plate plane (E) of at least one of the Be th (31, 32).

12. Device (1) according to claim 11, d a d u r c h g e k e n n z e i c h n e t that the frame (34) has flow guide means through which the metallization solution can be guided in the direction of the diffuser openings.

13. A method for electroless plating of a target surface of at least one workpiece (5), in particular with a device (1) according to one of the preceding claims, comprising the following method steps:

- Inserting at least one workpiece (5) into the holder (20),

- Positioning the holder (20) in the container filled with a metallizing solution and - Rinsing around the at least one workpiece (5) with the metallization solution by moving the diffuser plate (30) to form jets formed by the diffuser openings (35) in the metallization solution.

14. The method according to claim 13, characterized in that the diffuser plate (30) is moved cyclically by the movement device (40), and that alternately the jets emerge from the diffuser openings (35) and are generated by backflows flowing into the diffuser openings (35) become.

15. The method according to claim 13 or 14, g e k e n n z e i c h n e t d a d u r c h that the holder (20) with the least one workpiece

(5) is moved in the container (10) by the moving device (40) or that the holder (20) moves with the least one workpiece (5) in the container (10) by a further moving device independently of the diffuser plate (30) becomes.

16. Diffuser plate (30) for a device (1) according to one of claims 1 to 12 or for the method according to one of claims 13 to 15.