Method and apparatus for electroless deposition of at least one metal and method for electroless deposition of ni and pd

Abstract

The invention relates to a method and an apparatus for electroless deposition of at least one metal on at least one surface of at least one workpiece in a bath, and a method for electroless deposition of Ni and Pd on a Cu Redistrition Layer (RDL) structure on at least one wafer.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for current-free deposition of at least one metal on at least one surface of at least one workpiece in a tank, and a method for current-free deposition of Ni and Pd on a Cu redistribution layer (RDL) structure (Cu-RDL-structure) on at least one wafer. Background Technology

[0002] When Ni and Pd are deposited without current on a copper redistribution layer structure in a metallization bath, undesirable metal plating often forms on the passivation layer, especially in narrow structures, which can lead to short circuits between structures. This is particularly due to over-coating of these metals onto the structure. This can be seen, for example, in… Figure 1 and Figure 2 As can be seen, additional metallization 102 is visible on the insulating layer 101 in narrow locations between the plated Cu-RDL-structures 100, such as in narrow bends or at the narrower edges of closely spaced Cu-RDL-structures.

[0003] To date, this uncontrolled deposition of plating / coating has been suppressed as much as possible using so-called shield wafers, which are mounted in front of the corresponding wafer. Shield wafers are designed to increase chemical exchange through localized turbulence of plating chemicals on the wafer surface, thereby preventing uncontrolled plating in narrow structures. However, this limits the maximum number of wafers that can be introduced into the carrier or support, which reduces the efficiency of the process.

[0004] Furthermore, further improvements have been made to process control, as can be seen, for example, from US 11,566,329 B2 and US2021 / 0079529 A1. Summary of the Invention

[0005] According to the present invention, by using specially constructed tanks for optimized process control, and especially by adjusting the chemical parameters of the Ni plating bath and the wafer orientation within the tank, potentially uncontrolled Ni plating between narrow CuRDL structures on the passivation layer can be suppressed. Therefore, it is unnecessary to place special shield wafers in front of each wafer; instead, only an empty tank and / or a process carrier that can be fully filled with wafers is required to increase throughput. Shield wafers are not needed.

[0006] A first aspect of the present invention relates to a method for non-current deposition of at least one metal on at least one surface of at least one workpiece, comprising the steps of: The at least one workpiece is introduced and secured into the support device; The at least one workpiece fastened in the bearing device is introduced into a tank, wherein a metal solution is present in the tank, the metal solution comprising at least one metal or metal compound, at least one stabilizer, and at least one solvent; and The metal solution is used to flush at least one workpiece fastened in the support device, wherein the flushing is performed using at least one first nozzle at the bottom of the tank and at least one second nozzle at at least one side of the tank, wherein the metal solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and the metal is deposited.

[0007] A second aspect of the invention relates to a method for current-free deposition of Ni and Pd on a Cu redistribution layer structure on at least one wafer, comprising the steps of: The at least one wafer with the Cu redistribution layer structure is introduced and secured into the carrier device; The at least one wafer secured in the carrier device is introduced into a first tank, wherein a nickel solution is present in the first tank, the nickel solution comprising Ni or a nickel compound, as well as at least one first stabilizer and at least one first solvent; At least one wafer secured in the carrier device is rinsed with the nickel solution, wherein the rinsing is performed using at least one first nozzle at the bottom of the first tank and at least one second nozzle at at least one side of the first tank, wherein the nickel solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and Ni is deposited. Remove the at least one wafer secured in the carrier device from the first slot; The at least one first wafer is subjected to a first cleaning; At least one wafer secured in the carrier device is introduced into a second tank, wherein a palladium solution is present in the second tank, the palladium solution comprising Pd or a palladium compound, as well as at least one second stabilizer and at least one second solvent; At least one wafer secured in the carrier device is rinsed with the palladium solution, wherein the rinsing is performed using at least one third nozzle at the bottom of the second tank and at least one fourth nozzle at at least one side of the second tank, wherein the palladium solution is supplied to the at least one third nozzle and the at least one fourth nozzle via at least one third input line and at least one fourth input line, respectively, and Pd is deposited. Remove the at least one wafer secured in the carrier device from the second slot; A second cleaning is performed on the at least one wafer; and Optionally, the at least one wafer may be dried.

[0008] A third aspect of the invention relates to an apparatus for non-current deposition of at least one metal on at least one surface of at least one workpiece. The apparatus has the following features: A tank having at least one first nozzle at the bottom of the tank and at least one second nozzle at at least one side of the tank, wherein the at least one first nozzle is connected to at least one first input line and the at least one second nozzle is connected to at least one second input line, wherein the at least one first input line and the at least one second input line are configured to supply molten metal to the at least one first nozzle and the at least one second nozzle; A support device for the at least one workpiece, the support device being configured to hold the at least one workpiece, wherein the support device has at least one temporary fastening device by means of which the at least one first workpiece can be temporarily fastened in the support device, wherein the support device is configured to be able to introduce it into the tank such that the at least one workpiece is immersed in the molten metal in the tank; An introduction device is provided, on which the carrier device can be mounted, wherein the introduction device is configured to introduce the carrier device into the groove. The at least one first nozzle and the at least one second nozzle are configured to rinse the at least one workpiece with a molten metal solution.

[0009] Other aspects of the invention will become apparent from the detailed description in the specification. Attached Figure Description

[0010] The accompanying drawings are intended to illustrate embodiments of the invention and to provide a further understanding of the invention. They are used in conjunction with the description to explain the schemes and principles of the invention. Other embodiments and many mentioned advantages are given with reference to the accompanying drawings. Elements in the drawings are not necessarily drawn to scale. Identical, functionally identical, and equivalent elements, features, and components in the drawings are given the same reference numerals unless otherwise stated.

[0011] Figure 1 and Figure 2 This illustrates potential problems that may arise during coating processes using existing techniques.

[0012] Figure 3 The method according to the first aspect of the invention is illustrated schematically, while Figure 4 Another method according to the first aspect of the invention is illustrated schematically.

[0013] Figures 5 to 8 Details of an embodiment of the invention in which the workpiece is a wafer are shown.

[0014] Figure 9 The diagram illustrates the steps typically performed when using Ni and Pd for current-free metallization (NiPd plating) on ​​a CuRDL structure.

[0015] Figure 10 The method of the second aspect of the present invention is illustrated schematically.

[0016] exist Figure 11 The apparatus of the third aspect of the present invention is shown schematically in the figure.

[0017] Figure 12 A side view of an exemplary carrier device that can be used in the method according to the invention is shown.

[0018] Figure 13 and Figure 14 Details of the components of the exemplary device can be obtained.

[0019] Figure 15 and Figure 16 The diagram schematically shows the details of the Cu distribution layer coating.

[0020] Figure 17 and Figure 18 This is a photograph of the Cu-plated distribution layer manufactured according to the present invention. Detailed Implementation

[0021] definition Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] All scopes disclosed herein should be considered to be supplemented by the term “approximately” unless the opposite is explicitly defined or the context indicates otherwise. Expressions such as “about,” “approximately,” and combinations and variations thereof used herein are intended not only to include the exact quantity or value they refer to, but also to include some minor deviations that may be caused, for example, by manufacturing tolerances, measurement errors, wear, loads applied to the individual components, and combinations thereof.

[0023] The term “substantially” as used herein means that the parameter, event, or condition subsequently described occurs completely, or occurs to a large extent or within a wide range. For example, the term “substantially” means that the parameter, event, or condition subsequently described occurs at least 90% of the time, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99% of the time, or that the dimension or measurement is within at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99% of the relevant dimension or measurement.

[0024] The use of the terms "at least one" or "one or more" includes one as well as any number of more than one. Furthermore, the expression "at least one of X, Y, and Z" includes not only X, Y, and Z alone, but also any combination of X, Y, and Z.

[0025] The use of ordinal numbers (i.e., “first,” “second,” “third,” “fourth,” etc.) is only for distinguishing two or more objects and, unless otherwise explicitly stated, does not imply the order or importance of one object relative to another or the order of addition.

[0026] In the context of this invention, unless otherwise stated or apparent from the context, quantity data refers to weight percentage (Gew.%).

[0027] A first aspect of the present invention relates to a method for non-current deposition of at least one metal on at least one surface of at least one workpiece, comprising the steps of: At least one workpiece is introduced and secured into the carrier device; At least one workpiece fastened in a support device is introduced into a tank, wherein a molten metal is present in the tank, the molten metal comprising at least one metal or metal compound, at least one stabilizer, and at least one solvent; and At least one workpiece fastened in a support device is flushed with a molten metal solution, wherein the flushing is performed using at least one first nozzle at the bottom of the tank and at least one second nozzle at at least one side of the tank, wherein the molten metal solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and the metal is deposited.

[0028] There are no particular limitations on introducing and securing at least one workpiece into the support device. Suitable workpieces can be any workpiece used for metallization, but are preferably workpieces with a structure on at least one side to be metallized, particularly workpieces with a protrusion height of 5 µm or greater, preferably 7 µm or greater, such as 8 µm or greater, and / or a spacing between two protrusions of 30 µm or less, preferably 20 µm or less, such as 18 µm or less. Corresponding exemplary structures represent, for example, microstructures applied to a wafer. Accordingly, the exemplary workpiece is a wafer, which is not particularly limited and can be, for example, a wafer with a diameter of 100 mm or greater, such as 200 mm, 300 mm, or 400 mm.

[0029] Similarly, the carrier device is not limited and can be any device typically used to introduce the corresponding workpiece. Therefore, the carrier device can be, for example, a support commonly used for wafer metallization, and can accommodate, for example, multiple workpieces, such as 10 or more, or 20 or more, which can be suitably secured to the carrier device. For wafers, this securing can also be achieved, for example, via a notch (a cut at the edge of the wafer). Accordingly, in a preferred embodiment, multiple workpieces are introduced and secured in the carrier device before being rinsed. However, the method is not limited to the introduction and securing of wafers, and other workpieces (e.g., those with microstructures), such as microfluidic components, printed circuit boards, interposers, microsystems (MEMS), etc., can also be metallized. The carrier device can be adapted accordingly to the at least one workpiece.

[0030] Preferably, the carrier is configured so as not to obstruct rinsing, for example, by constructing a mesh device with connecting tabs (e.g., 2 to 10, such as 2 to 4), for example, with thin tabs (e.g., 0.1 to 20 cm in diameter) of substantially circular diameter, on which at least one workpiece can be secured using at least one suitable temporary fastening device. The type of fastening is not particularly limited and includes, for example, hooks, inserts, clamps, etc. Depending on the specific embodiment, the carrier is adapted to the trough. For example, if the trough is cuboid or cubic, the carrier can also be cuboid or cubic. For rinsing multiple workpieces, a cuboid trough together with a cuboid carrier can be advantageous to achieve laminar flow from at least one nozzle, thereby achieving rinsing as uniformly as possible.

[0031] Similarly, there are no particular restrictions on introducing at least one workpiece secured in the support device into the tank, where a molten metal is present, the molten metal comprising at least one metal or metal compound, at least one stabilizer, and at least one solvent. Here, introducing at least one workpiece into the tank means that the workpiece is as completely surrounded by the molten metal as possible, except for the temporary fastening portion of the at least one workpiece at the support device. The support device itself need not be completely immersed in the molten metal.

[0032] The metal solution is not particularly limited, provided it contains at least one metal or metal compound, at least one stabilizer, and at least one solvent. Here, a metal or metal compound suitable for current-free metallization can be selected. Thus, for example, metallization can be carried out at a suitable pH using a metal compound and a reducing agent, wherein, however, other deposition feasibility, such as by means of chemical deposition, can also be considered. The solvent is not limited and may contain, for example, water and / or other solvents, including organic solvents, or preferably water. Other salts may also be present in the metal solution if desired. The metal or metal compound, such as a metal salt, is not limited. During rinsing, the entire metal solution is always supplied. This can be done, for example, by circulating it in a loop, i.e., by pump circulation, wherein the metal solution is discharged here at at least one location in the tank, for example at the upper end of the tank, opposite the bottom at the edge of the tank.

[0033] A stabilizer is a compound or a substance designed to inhibit so-called runaway metallization (random plating), which can lead to short circuits and / or damage to microstructures in subsequent applications, such as electronic applications. Suitable stabilizers are, for example, known from publications such as *Applied Surface Science* (Volume 229, Issues 1-4, 15 2004, pp. 282-300) or EP2339050A1, and include, for example, compounds containing Group IV to VI elements in nickel deposition (e.g., Pb, Sb, Se, Te, thiourea, MBT (mercaptobenzothiazole), thiocyanates, etc.); unsaturated organic acids (e.g., maleic acid, itaconic acid, etc.); and heavy metal cations (e.g., Sn). 2+ Pb 2+ Cu 2+ etc.); oxygen-containing anions (e.g., AsO2) 2- MoO4 2- (etc.); as well as several types of surfactants, dispersants and emulsifiers (such as potassium perfluoroalkyl sulfonate, lauryltrimethylammonium chloride, N-oleoyl betaine, etc.).

[0034] The concentration of the corresponding component can be appropriately adapted to the corresponding metallization. Stabilizers can be used to poison the metal deposition, for example at the boundary with an uncoated structure (e.g., an insulating layer), such as in a Cu-RDL structure.

[0035] The trough in the method according to the invention is not particularly limited, as long as it allows rinsing using at least one first nozzle at the bottom of the trough and at least one second nozzle at at least one side of the trough. The trough can be made of a suitable material as commonly used in metallization and adapted in shape to the metallization, as exemplarily described above. For rinsing at least one workpiece fastened in a support device with molten metal, at least one first nozzle is provided at the bottom of the trough, and at least one second nozzle is provided at at least one side of the trough, wherein the at least one first nozzle and the at least one second nozzle are respectively connected to at least one first input line and at least one second input line, through which molten metal can be supplied to the respective nozzles. The shape and configuration of the respective nozzles and the respective input lines are not particularly limited herein. The respective nozzles and input lines can be inserted into and / or mounted on the trough. For example, the at least one first nozzle at the bottom of the trough may comprise a plurality of first nozzles, for example, in the form of a diffuser plate. Other nozzle shapes are also contemplated, for example, for the at least one first nozzle and the at least one second nozzle, as a planar nozzle for more uniform laminar flow, as a slit nozzle, etc.

[0036] According to a specific embodiment, a plurality of second nozzles are present, wherein the number of second nozzles corresponds at least to the number of workpieces introduced. Preferably, at least a plurality of second nozzles are installed, i.e., if multiple workpieces are introduced, they respectively rinsing one of the multiple workpieces. To achieve a more uniform circulation, it may be advantageous to have more second nozzles than workpieces, for example, for 25 workpieces (e.g., wafers), at least two additional nozzles at the edges, i.e., 27 second nozzles. Furthermore, it is not excluded that a plurality of second nozzles may also be installed or introduced, stacked vertically, on at least one side of the tank, for example at two or more parallel second input lines (e.g., spray bars). According to a specific embodiment, at at least one side of the tank, preferably on at least two opposing sides of the tank, for example in a generally cuboid tank, a plurality of second nozzles are arranged on a plurality of second input lines to achieve a more uniform rinsing.

[0037] Compared to existing technologies, the method according to the invention modifies the tank design. One or more (e.g., two, three, or more) lateral nozzle strings are introduced, preferably with at least one nozzle per workpiece or slot on each fastening empty space or carrier (process carrier). Preferably, such nozzle strings are also introduced or mounted parallel to the nozzle as a second input line on the opposite side of the tank. This results in improved exchange during metallization, particularly at structural points on the workpiece, such as regarding plating chemicals in narrow CuRDL structures, eliminating the need for shielding workpieces (e.g., shielded workpieces, such as shielded wafers). According to certain embodiments, shielding workpieces are not used in the method. According to existing technologies, they are used to reduce turbulence.

[0038] exist Figure 3 The diagram schematically illustrates an exemplary method according to the invention, wherein, after step 1 of introducing and securing at least one workpiece into a support device, step 2 is performed to introduce at least one workpiece secured in the support device into a tank, wherein a metal solution is present in the tank, the metal solution comprising at least one metal or metal compound, at least one stabilizer, and at least one solvent, and the subsequent step 3 is to rinse at least one workpiece secured in the support device with the metal solution, wherein the rinsing is performed using at least one first nozzle at the bottom of the tank and at least one second nozzle at at least one side of the tank, wherein the metal solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, accompanied by metal deposition.

[0039] According to a specific implementation, during rinsing, the carrier is moved in the tank using 3D agitation. This can be achieved, for example, via a suitable introduction device onto which the carrier can be mounted and which can perform the corresponding agitation, such as a gripping arm or robotic arm, a 3D actuator onto which the carrier can be mounted, or a corresponding mechanical 3D lowering device, etc. By using 3D agitation of the entire carrier during metallization instead of conventional 2D agitation, further improved uniform metallization or metal deposition is achieved through better exchange of plating chemicals in narrow structures, especially at corners of the workpiece structure. In 2D or 1D agitation, a thicker deposition is produced on the upstream side.

[0040] 3D agitation is not particularly limited and can be performed in any form. However, it has been shown that spherical or ellipsoidal motion can achieve more uniform metal deposition. Preferably, the motion is performed at a rate of 1-60 cycles per minute, more preferably 10-40 cycles per minute, and even more preferably 15-20 cycles per minute. Reciprocating and / or lateral motion is not particularly limited. For example, the motion in both directions can be 0.1 to 5.0 cm, such as 0.5 to 3.5 cm, or even 2.0 to 3.0 cm, to further improve metal deposition. For this purpose, for example, a gripping arm can be used simultaneously as an introduction device and an agitator, introducing the carrier into the tank from above, and then moving within the tank during rinsing.

[0041] Figure 4 The diagram schematically illustrates another method according to the invention with agitation, wherein step 3a follows steps 1 to 3, wherein the carrier device is moved in the tank using 3D agitation during rinsing.

[0042] According to a specific embodiment, the at least one workpiece is a wafer comprising a notched (cut) structure, wherein the wafer is introduced into a carrier such that the largest surface of the wafer is substantially parallel to one side of the groove. This allows for a more uniform circulation. Preferably, the at least one second nozzle is mounted such that it flushes the wafer with molten metal along the largest surface. Especially in the case of multiple second nozzles, and indeed generally, uniform flushing of the workpiece and structure occurs, particularly uniform flushing of the material to the largest surface, such as the disk surface of the wafer, thus allowing for selective flushing of structures on that surface for metal deposition. According to a preferred embodiment, the structure is correspondingly located on the largest surface of the wafer, more preferably on only one largest surface. This also produces a uniform, substantially laminar flow, minimizing concentration differences in metal deposition, an effect further improved by combining 3D agitation.

[0043] According to a particular embodiment, the structure is applied to the wafer at an angle of 0° and / or 90° relative to an imaginary line passing through the center of the notch (i.e., the bisector of the notch angle) or its parallel line, wherein the wafer is held in a carrier such that the imaginary line passing through the center of the notch is rotated by an angle relative to the depth direction of the notch (i.e., from the upper open end into which the carrier can be introduced toward the bottom), wherein, according to a particular embodiment, this angle is between 15° and 75°, preferably between 30° and 60°, more preferably around 45°, and particularly preferably 45°. The structure here is particularly a Cu-RDL structure, which, according to a particular embodiment, has parallel tracks that are connected at the ends by transverse tracks and 90° curves.

[0044] Figure 5 The diagram illustrates a corresponding configuration of a wafer W with a notch N in a carrier device, wherein the notch is mounted on a connecting patch 32a at an angle of 0° relative to the depth direction (from top to bottom), and a structure S is applied to the wafer W at an angle of 0° and / or 90° relative to an imaginary line passing through the center of the notch N or its parallel line. This corresponds to a common introduction according to the prior art.

[0045] In contrast, Figure 6 In this configuration, structure S is located on wafer W within the carrier device at an angle of 45° relative to the depth direction. Accordingly, the positioning of wafer W is considered to be rotated 45° within the carrier device compared to previous introductions according to the prior art.

[0046] exist Figure 7 The image now schematically shows at least one first nozzle from the bottom of the trough and at least one second nozzle from one side of the trough, and encountering... Figure 6 The flow directions S1 and S2 on the wafer are shown schematically here. Flows S1 and S2 encounter each other on the actual structure. Figure 8 middle.

[0047] By rotating the structure relative to the flow direction, a more uniform flow was also achieved at the corners, whereas without rotation, flow S1 from the bottom, for example, might stagnate on the lateral tabs. Accordingly, this rotation further supports more uniform metallization.

[0048] In addition, the tank may have other devices that are typically provided in the tank for metallization, such as one or more heating devices, which may be installed, for example, at the bottom of the tank, or otherwise installed, for example on the first and / or second inlet lines.

[0049] Furthermore, it was unexpectedly discovered that improved metallization was achieved not only through equipment-related measures, but also through modifications to the metal solution itself. In particular, it was found that improved uniformity of metallization was achieved by utilizing an increased stabilizer concentration compared to existing techniques, especially at the corners and edges of the structure to be metallized, particularly when metallizing with nickel, and even more particularly when metallizing with nickel on Cu redistribution layer structures. For example, in nickel deposition to date, the stabilizer concentration is typically limited to 1.4 ppm. According to specific embodiments, the stabilizer in the metal solution is present at a concentration greater than 1.6 ppm (ppm, 0.0016 Gew.%), particularly greater than 1.7 ppm (0.0017 Gew.%), and / or at a concentration less than 2.0 ppm (0.0020 Gew.%), preferably less than 1.9 ppm (0.0019 Gew.%), for example, at a concentration of approximately 1.8 ppm (0.0018 Gew.%). According to a specific implementation method, for example, the concentration of the stabilizer in the currentless Ni bath is increased from 1.4 ppm to 1.8 ppm.

[0050] According to specific embodiments, the metal solution contains nickel or palladium. In particular, this method has proven advantageous when metallizing with nickel and palladium, especially in Cu-RDL structures.

[0051] One example where the first approach can even be applied twice is the metallization or plating of Cu-RDL structures using Ni and Pd, which is generally referred to here. Figure 9 An exemplary description is provided.

[0052] Here, typically in the first step, during the pre-dip step, copper oxide removal 11 is performed, followed immediately by a cleaning 12, also known as a rapid drain rinse (QDR). This is followed by Cu etching 13, another cleaning 14, acid conditioning of the Cu surface as another pre-dip step 15, and catalytic activation of the Cu surface using Pd 16 and cleaning 17. Subsequently, as a first example of applying the method according to the first aspect of the invention, electroless Ni deposition 18 is performed, followed by another cleaning 19. As a second example of applying the method according to the first aspect of the invention, electroless Pd deposition 20 is then performed, followed by cleaning 21 and drying 22. This represents an exemplary process flow for electroless NiPd plating on a CuRDL structure. In this process flow, the method according to the first aspect of the invention is applied twice accordingly.

[0053] Therefore, another aspect of the present invention relates to a method for current-free deposition of Ni and Pd on a Cu redistribution layer structure on at least one wafer, comprising the following steps: At least one wafer with a Cu redistribution layer structure is introduced and secured into a carrier device; At least one wafer, secured in a carrier device, is introduced into a first tank, wherein a nickel solution is present in the first tank, the nickel solution comprising Ni or a nickel compound, and at least one first stabilizer and at least one first solvent; and At least one wafer secured in a carrier device is rinsed with a nickel solution, wherein rinsing is performed using at least one first nozzle at the bottom of a first tank and at least one second nozzle at at least one side of the first tank, wherein the nickel solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and Ni is deposited. Remove the at least one wafer secured in the carrier device from the first slot; The at least one first wafer is subjected to a first cleaning; At least one wafer, secured in a carrier device, is introduced into a second tank, wherein a palladium solution is present in the second tank, the palladium solution comprising Pd or a palladium compound, and at least one second stabilizer and at least one second solvent; and At least one wafer secured in a carrier device is rinsed with a palladium solution, wherein rinsing is performed using at least one third nozzle at the bottom of a second tank and at least one fourth nozzle at at least one side of the second tank, wherein the palladium solution is supplied to the at least one third nozzle and the at least one fourth nozzle via at least one third input line and at least one fourth input line, respectively, and Pd is deposited. At least one wafer secured in the carrier device is removed from the second slot; A second cleaning is performed on the at least one wafer; and Optionally, the at least one wafer may be dried.

[0054] In this method, two specific methods of the first aspect are particularly performed for metallization with nickel followed by metallization with palladium. Accordingly, the above description also applies to this method, particularly in the steps of introducing and securing at least one wafer, introducing at least one wafer secured in the carrier device into the first or second tank, and rinsing the at least one wafer secured in the carrier device with the corresponding metal solution (nickel, palladium). At least one third nozzle may be configured to correspond to or differ from the at least one first nozzle, and at least one fourth nozzle may be configured to correspond to or differ from the at least one second nozzle. The corresponding input lines (first and third input lines; second and fourth input lines) may also be configured similarly or differently. The at least one first stabilizer and at least one second stabilizer may be the same or different, and, for example, correspond to the stabilizers of the method of the first aspect. A similar situation applies to the at least one first solvent and at least one second solvent.

[0055] Removal from the first and second slots is unrestricted and can be appropriately performed using the introduction device in a similar manner to the introduction described. Preferably, the same introduction device is used for introducing into and removing from the first slot, as well as for introducing into and removing from the second slot.

[0056] There are no particular limitations on the first and second cleaning of the at least one wafer. For example, it can be washed and / or immersed in a suitable solvent, wherein the solvent may correspond to the corresponding solvent of the metal solution (e.g., water). There are no limitations on the optional drying of the at least one wafer.

[0057] According to a specific embodiment, the at least one first stabilizer is present in the nickel solution at a concentration greater than 1.6 ppm (ppm, 0.0016 Gew.%), particularly at a concentration greater than 1.7 ppm (0.0017 Gew.%), and / or at a concentration less than 2.0 ppm (0.0020 Gew.%), preferably at a concentration less than 1.9 ppm (0.0019 Gew.%), for example at a concentration of about 1.8 ppm (0.0018 Gew.%).

[0058] Figure 10An exemplary configuration of the second aspect of the method is schematically illustrated. Immediately following step 1a, introducing and securing at least one wafer with a Cu redistribution layer structure to a carrier device, is step 2a, introducing the at least one wafer secured in the carrier device into a first tank, wherein a nickel solution is present in the first tank, the nickel solution comprising Ni or a nickel compound, as well as at least one first stabilizer and at least one first solvent. Then, step 18a is performed by rinsing the at least one wafer secured in the carrier device with the nickel solution, wherein this rinsing is carried out using both at least one first nozzle at the bottom of the first tank and at least one second nozzle at at least one side of the first tank, wherein the nickel solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and Ni is deposited. Step 4a follows, removing the at least one wafer secured in the carrier device from the first tank, and step 19, performing a first cleaning on the at least one first wafer. Then, in step 2b, at least one wafer secured in the carrier is introduced into a second tank, wherein a palladium solution containing Pd or a palladium compound, at least one second stabilizer, and at least one second solvent are present in the second tank. In step 20a, at least one wafer secured in the carrier is rinsed with the palladium solution, wherein the rinsing is performed using at least one third nozzle at the bottom of the second tank and at least one fourth nozzle at at least one side of the second tank, wherein the palladium solution is supplied to the at least one third nozzle and the at least one fourth nozzle via at least one third input line and at least one fourth input line, respectively, and Pd is deposited. In step 4b, at least one wafer secured in the carrier is removed from the second tank. In step 21, at least one wafer is subjected to a second cleaning. In step 22, at least one wafer is optionally dried.

[0059] Another aspect of the invention relates to an apparatus for non-current deposition of at least one metal on at least one surface of at least one workpiece. The apparatus has the following features: A tank having at least one first nozzle at the bottom and at least one second nozzle at at least one side of the tank, wherein the at least one first nozzle is connected to at least one first input line and the at least one second nozzle is connected to at least one second input line, wherein the at least one first input line and the at least one second input line are configured to supply molten metal to the at least one first nozzle and the at least one second nozzle. A carrying device for the at least one workpiece, the carrying device being configured to hold at least one workpiece, wherein the carrying device has at least one temporary fastening device by means of which at least one first workpiece can be temporarily fastened in the carrying device, wherein the carrying device is configured to be introduced into a tank such that at least one workpiece is immersed in the molten metal in the tank. An introduction device is provided, on which a carrier device can be mounted, wherein the introduction device is configured to introduce the carrier device into the groove. The at least one first nozzle and the at least one second nozzle are configured to rinse the at least one workpiece with a molten metal solution.

[0060] Using the device of the third aspect, the method of the first aspect can be performed in particular, so that the corresponding description of the method of the first aspect also applies here. In particular, the carrying device and the groove with the corresponding nozzle and input line, as described above, are like the inlet device, and therefore this applies accordingly here.

[0061] Figure 11 The device according to the invention is schematically shown, having a carrying device 32, an inlet device 33, and a groove 31, wherein a first nozzle 31a and a second nozzle 31b are installed in the groove 31 (here, in the groove), and they have corresponding input lines, which are not shown for better visibility.

[0062] It should be noted that, similar to the second method, another device including the fourth aspect comprises: A first tank has at least one first nozzle at its bottom and at least one second nozzle at at least one side of the first tank, wherein the at least one first nozzle is connected to at least one first input line and the at least one second nozzle is connected to at least one second input line, wherein the at least one first input line and the at least one second input line are configured to supply molten metal, in this case, a nickel solution, to the at least one first nozzle and the at least one second nozzle. A second tank has at least one third nozzle at its bottom and at least one fourth nozzle at at least one side of the tank, wherein the at least one third nozzle is connected to at least one third input line and the at least one fourth nozzle is connected to at least one fourth input line, wherein the at least one third input line and the at least one fourth input line are configured to supply a metal solution, in this case, palladium solution, to the at least one third nozzle and the at least one fourth nozzle. A support device for the at least one workpiece, the support device being configured to hold the at least one workpiece, wherein the support device has at least one temporary fastening device by means of which the at least one first workpiece can be temporarily fastened in the support device, wherein the support device is configured to introduce it into first and second tanks such that at least one workpiece is immersed in the corresponding metal solution in the tanks. An introduction device is provided, on which a carrier device can be mounted, wherein the introduction device is configured to introduce the carrier device into the groove. The at least one first nozzle, at least one second nozzle, at least one third nozzle, and at least one fourth nozzle are configured to rinse the at least one workpiece with a corresponding metal solution (nickel solution or palladium solution).

[0063] According to a particular embodiment, the first tank includes, or the first and second tanks include, a plurality of first, second, third, and fourth nozzles. According to a particular embodiment, a diffuser plate may be placed at the bottom of the tank above the first or first and / or third nozzles, or above the plurality of first or first and / or third nozzles, to generate a uniform flow of coating chemicals throughout the respective tank. According to a particular embodiment, the respective tank has an overflow of coating chemicals in all four lateral directions to further support uniform flow.

[0064] According to a specific embodiment, an apparatus is introduced to move the carrier device within the tank during rinsing using 3D agitation. Corresponding configurations, such as those with gripping arms, have already been described above.

[0065] According to a particular embodiment, the at least one workpiece is a wafer comprising a notched structure, wherein the structure is applied to the wafer at an angle of 0° and / or 90° relative to an imaginary line passing through the center of the notch or its parallel line. The carrier is preferably configured to secure the wafer in a retaining portion such that the imaginary line passing through the center of the notch is rotated by an angle relative to the depth direction of the notch, wherein this angle is preferably 45 degrees. This is also as described above, and therefore references the previously provided content.

[0066] Wherever meaningful, the above-described embodiments, configurations, and extensions can be combined arbitrarily. Other feasible configurations, extensions, and implementations of the invention include combinations of features of the invention not explicitly mentioned previously or described below in conjunction with embodiments. In particular, those skilled in the art will also add individual aspects as improvements or supplements to the corresponding basic forms of the invention.

[0067] The invention will then be described in further detail with reference to different embodiments thereof. However, the invention is not limited to these embodiments.

[0068] Example Example 1: Metallization of Cu distribution structure on a 300 mm diameter wafer using Ni and Pd In an exemplary method, a wafer W with a Cu-RDL structure is introduced into a substrate according to... Figure 12 In the exemplary carrier device 32', wherein, exemplarily shown here, a carrier device 32' for 26 wafers W is provided, which here does not require shield wafers and can therefore be completely filled with wafers W. Figure 6 As shown, the wafer W is introduced into the carrier device 32' by rotating it 45° relative to the depth direction.

[0069] Then the bearing device 32' is successively introduced according to... Figure 13 and Figure 14 The first and second tanks of the configuration each have a diffuser plate 31a' at the bottom serving as a plurality of first or third nozzles and a spray bar 31b' at the side of the respective tank serving as a plurality of second or fourth nozzles, wherein a rinsing step is performed using water. This is achieved via two blocks on the support device 32' (in... Figure 12 (shown at the top) and the corresponding hook of the introduction device, for fastening on the introduction device (here, the gripping arm).

[0070] According to the prior art, the wafer is rinsed in a first tank with a nickel solution through first and second nozzles, wherein the temperature is set to 84°C by a first tank heater 34, and the concentration of stabilizer is increased from 1.4 ppm to 1.8 ppm compared to the prior art. During rinsing, the carrier device 32' is moved elliptically between positions 32b and 32b' (and also in the height direction) via an introduction device (not shown).

[0071] Movement was also performed while rinsing with a palladium solution corresponding to the prior art, but the temperature for palladium deposition was set to 60°C.

[0072] The next step is to rinse with water. Afterward, drying can be carried out using existing technology.

[0073] exist Figure 15 The diagram schematically illustrates the uniform deposition of a Ni coating followed by a Pd coating on a Cu redistribution layer (CuRDL) structure on wafer W using this method. Figure 16 As schematically shown, no random plating of Ni and Pd occurs in the region of the narrow point 102a on the insulating layer 103. This is... Figure 17 and Figure 18The NiPd coating is clearly visible in the micrographs of the wafer slices, where it can be seen on the CuRDL / Cu-RDL structure, but the insulating layer 103 remains uncoated. Depending on the deposition duration and metal concentration, Ni deposits with a thickness of 1000-2000 nm and Pd deposits with a thickness of 200-500 nm were produced. Deposition of uncontrollable Ni coatings without occurring between narrow CuRDLs was achieved.

[0074] Comparative Example: The method was performed as in Example 1, however, the stabilizer concentration in the Ni pool was maintained at 1.4 ppm, the wafer W was introduced into the carrier 32' without being rotated 45°, the gripper arm performed only up-and-down movement during coating, and the metal solution was supplied only through the diffuser plate 31a'. As in... Figure 1 and Figure 2 As shown, uncontrolled metallization occurs at narrow points and corners.

[0075] By introducing grooves with side nozzles in each wafer slot of the carrier (process carrier), combined with laminar flow from the bottom of the groove, and introducing 3D agitation relative to the 2D agitation of the carrier, 300mm wafers can be processed without the need for dedicated shielding wafers, which do not exhibit uncontrolled Ni plating in narrow CuRDL structures. To further achieve good exchange of plating chemicals in narrow RDL structures, the notched wafers are rotated 45° and placed in the carrier to better flush the RDL lines at a 45° angle to the solution flow, as RDL structures are typically placed on the chip at 90° angles to each other, resulting in poorer chemical exchange in the trenches between structures, especially for RDL lines with horizontal flow directions. Furthermore, it has been shown that by slightly adjusting (increasing) the stabilizer concentration in the currentless Ni plating bath, not only can a fully filled carrier be coated with Ni without shielding wafers or empty slots between wafers, but also without uncontrolled plating in narrow RDL structures, thereby doubling the processing capacity of the equipment.

[0076] The advantages of this are: avoiding short circuits between RDL structures; higher wafer handling capacity and simpler processing in the wet bench due to the elimination of shield wafers between wafers; and allowing the carrier to be fully loaded with wafers, thus increasing processing capacity.

Claims

1. A method for non-current deposition of at least one metal on at least one surface of at least one workpiece, comprising the steps of: (1) Introduce and secure the at least one workpiece into the support device (32); (2) The at least one workpiece fastened in the bearing device (32) is introduced into a tank (31), wherein a metal solution is present in the tank (31), the metal solution comprising at least one metal or metal compound, at least one stabilizer, and at least one solvent; and (3) The at least one workpiece fastened in the support device (32) is rinsed with the molten metal, wherein the rinsing is performed using at least one first nozzle (31a) at the bottom of the tank and at least one second nozzle (31b) at at least one side of the tank, wherein the molten metal is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line (31a') and at least one second input line (31b'), respectively, and the metal is deposited.

2. The method according to claim 1, wherein, The carrier device moves within the tank during the rinsing process using 3D agitation (3a).

3. The method according to claim 1 or 2, wherein, The at least one workpiece is a wafer (W) comprising a structure (S) with a notch (N), wherein the wafer (W) is introduced into the carrier such that the maximum surface of the wafer is substantially parallel to one side of the groove, preferably wherein the at least one second nozzle is mounted such that it washes the wafer with the molten metal along the maximum surface.

4. The method according to claim 3, wherein, The structure is applied to the wafer at an angle of 0° and / or 90° relative to an imaginary line or its parallel line passing through the center of the notch, wherein the wafer is held in the carrier such that the imaginary line passing through the center of the notch is rotated by an angle relative to the depth direction of the notch, wherein the angle is preferably 45 degrees.

5. The method according to any one of the preceding claims, wherein, The stabilizer in the metal solution is present at a concentration greater than 1.6 ppm.

6. The method according to any one of the preceding claims, wherein, The metal solution contains nickel or palladium.

7. A method for current-free deposition of Ni and Pd on a Cu redistribution layer structure on at least one wafer, comprising the following steps: The at least one wafer with the Cu redistribution layer structure is introduced and secured into the carrier device; The at least one wafer secured in the carrier device is introduced into a first tank, wherein a nickel solution is present in the first tank, the nickel solution comprising Ni or a nickel compound and at least one first stabilizer and at least one first solvent; The at least one wafer secured in the carrier device is rinsed with the nickel solution, wherein the rinsing is performed using at least one first nozzle at the bottom of the first tank and at least one second nozzle at at least one side of the first tank, wherein the nickel solution is supplied to the at least one first nozzle and the at least one second nozzle via at least one first input line and at least one second input line, respectively, and Ni is deposited. Remove the at least one wafer secured in the carrier device from the first slot; The at least one first wafer is subjected to a first cleaning; The at least one wafer secured in the carrier device is introduced into a second tank, wherein a palladium solution is present in the second tank, the palladium solution comprising Pd or a palladium compound, as well as at least one second stabilizer and at least one second solvent; The palladium solution is used to rinse the at least one wafer secured in the carrier device, wherein the rinsing is performed using at least one third nozzle at the bottom of the second tank and at least one fourth nozzle at at least one side of the second tank, wherein the palladium solution is supplied to the at least one third nozzle and the at least one fourth nozzle via at least one third input line and at least one fourth input line, respectively, and Pd is deposited. Remove the at least one wafer secured in the carrier device from the second slot; A second cleaning is performed on the at least one wafer; and Optionally, the at least one wafer may be dried.

8. An apparatus for non-current deposition of at least one metal on at least one surface of at least one workpiece, comprising: A groove, the groove having at least one first nozzle at its bottom and at least one second nozzle at at least one side of the groove, wherein, The at least one first nozzle is connected to at least one first input line, and the at least one second nozzle is connected to at least one second input line, wherein the at least one first input line and the at least one second input line are configured to supply molten metal to the at least one first nozzle and the at least one second nozzle; A support device for the at least one workpiece, the support device being configured to hold the at least one workpiece, wherein the support device has at least one temporary fastening device by means of which the at least one first workpiece can be temporarily fastened in the support device, wherein the support device is configured to be able to introduce it into the tank such that the at least one workpiece is immersed in the molten metal in the tank; An introduction device is provided, on which the carrier device can be mounted, wherein the introduction device is configured to introduce the carrier device into the groove. The at least one first nozzle and the at least one second nozzle are configured to rinse the at least one workpiece with a molten metal solution.

9. The device according to claim 7, wherein, The introduction device is configured to move the carrier device in the tank during the rinsing process using 3D agitation.

10. The device according to claim 7 or 8, wherein, The at least one workpiece is a wafer comprising a notched structure, and the structure is applied to the wafer at an angle of 0° and / or 90° relative to an imaginary line or its parallel line passing through the center of the notch, wherein the carrier is configured to secure the wafer in a retainer such that the imaginary line passing through the center of the notch is rotated by an angle relative to the depth direction of the notch, wherein the angle is preferably 45 degrees.

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