Electrohydrodynamic extrusion printing and electroplating for forming metallic features without using photoresists.

Abstract

Provided herein are methods, inks, devices, and systems for forming metal features on semiconductor substrates. Advantageously, the techniques herein do not require the use of photoresist and can be accomplished without many of the processes and equipment used in conventional process flows. Instead, electrohydrodynamic ejection printing is used to deposit an ink containing electroplating additives, such as accelerators or inhibitors. The printed substrate can then be electroplated with a preferential deposition process that achieves a first deposition rate in areas of the substrate where the ink is present and a second deposition rate in areas of the substrate where the ink is not present, the first and second deposition rates being different from one another. After electroplating, chemical etching may be used to spatially isolate the preferentially grown metal features from one another.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] The PCT application form is submitted herewith as part of this application. Each application for which this application claims benefit or priority, as identified in the concurrently submitted PCT application form, is hereby incorporated by reference in its entirety as if fully set forth herein.

Background Art

[0002] The fabrication of semiconductor devices generally involves a series of steps for forming fine wire interconnects or other metallic features. Such features may be formed during several processing steps involving many different semiconductor processing facilities. For example, in the field of 3D packaging, metal coating may involve steps of forming a conductive seed layer on a substrate, forming a photoresist layer on the seed layer, exposing and developing the photoresist layer to define a pattern therein, descumming the substrate to remove any unwanted photoresist remaining inside the patterned features, plating the substrate with metal, stripping the photoresist, and removing any exposed seed layer that had been protected by the photoresist until now.

[0003] The background description provided herein is generally for the purpose of presenting the context of the present disclosure. Within the scope of the description of this background art, neither the works of the inventors named herein only nor descriptions in other respects that would not be considered prior art at the time of filing are admitted as prior art to the present disclosure, either expressly or implicitly.

Summary of the Invention

[0004] Various embodiments of this specification relate to methods, apparatus, systems, inks, and electroplating electrolytes for electrohydrodynamic extrusion printing and electroplating. The techniques described herein enable the formation of metallic features without the use of photoresists, substantially simplify the processing methods for forming such features, and minimize associated capital and processing costs. Generally, the techniques herein utilize specific inks containing one or more electroplating additives, such as plating accelerators or plating inhibitors. The ink is selectively printed onto a substrate in a desired pattern, and the additives react with the substrate surface to become strongly adsorbed onto the surface. After the ink dries, the substrate is electroplated, and the adsorbed electroplating additives obtained from the printed ink remain adsorbed on the printed surface, resulting in a preferential plating process that provides a unique plating rate in the printed areas compared to the non-printed areas of the substrate. As a result of the unique plating rate, metallic features are formed. After plating, the features can be electrically and spatially isolated from each other by etching.

[0005] In one embodiment of the disclosed features, a method for plating a metal onto a substrate is provided, comprising: (a) receiving a substrate including a conductive seed layer exposed on the surface of the substrate; (b) printing an ink onto the seed layer in a pattern by electrohydrodynamic extrusion printing, wherein the ink comprises an electroplating additive dissolved in a solvent, the electroplating additive comprises an accelerator or inhibitor, and the electroplating additive is strongly adsorbed onto the seed layer; and (c) electroplating the metal onto the substrate by preferential deposition, providing a first deposition rate where the electroplating additive obtained from the ink is present and a second deposition rate where the ink is absent, the first deposition rate being different from the second deposition rate.

[0006] In some embodiments, the electroplating additive includes an accelerator, and the first deposition rate is faster than the second deposition rate so that metal is preferentially deposited where the accelerator obtained from the ink is present. In these and other embodiments, the accelerator may include at least one mercapto group or at least one sulfonic acid group, or an alkane chain with an acidic salt. In examples, the accelerator may include mercaptopropanesulfonic acid or mercaptoethanesulfonic acid. In these and other embodiments, the solvent in the ink may include at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol.

[0007] The method may further include the step of chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming metallic features that are spatially isolated from each other in the presence of the accelerator obtained from the ink. In some such cases, the substrate is electroplated in (c) in an electrolyte containing a plating inhibitor additive between about 10 ppm and 1000 ppm, copper ions between about 10 g / L and 60 g / L, an acid between about 5 g / L and 180 g / L, and halide ions between about 30 ppm and 80 ppm. In such embodiments, the accelerator in the electrolyte (if present) tends to increase the plating rate in areas where the accelerator obtained from the ink is absent (e.g., non-printed areas) and tends to reduce the significant difference in deposition rate between printed and non-printed areas. Thus, in various embodiments, the electrolyte may have no accelerator or only a small amount of accelerator.

[0008] In some embodiments, the electroplating additive includes an inhibitor. In such embodiments, the first deposition rate is slower than the second deposition rate so that metal is preferentially deposited in areas where the inhibitor obtained from the ink is absent.

[0009] In certain embodiments, the method may further include the step of chemically etching the substrate to remove a portion of the metal deposited in (c), the ink printed in (b), and a portion of the seed layer, thereby forming spatially isolated metallic features in areas where the inhibitor obtained from the ink was not present. In some cases where an inhibitor is used, the substrate may be electroplated in (c) in an electrolyte containing an accelerator between approximately 0 ppm and 1000 ppm, copper ions between approximately 10 g / L and 60 g / L, and an acid between approximately 5 g / L and 180 g / L. In various embodiments, the electrolyte may have no inhibitor or only a trace amount of an inhibitor. In some such cases, the electrolyte may also have no plating inhibitor additive or only a trace amount of a plating inhibitor additive.

[0010] In some embodiments, the substrate further includes an adhesive barrier layer positioned directly beneath the seed layer. The method may further include (d) chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming spatially isolated metallic features; and (e) electroplating the substrate with a second metal that selectively deposits on the metallic features formed in (d) without substantially forming on the adhesive barrier layer. In some such cases, the second metal may form a diffusion barrier layer. The method may further include (f) electroplating the diffusion barrier layer with a solder material that selectively deposits on the diffusion barrier layer formed in (e) without substantially forming on the adhesive barrier layer. In various embodiments, the electroplating additive in the ink reacts with the seed layer on the substrate and chemically bonds to the seed layer on the substrate.

[0011] Another embodiment of the disclosed features provides an electrohydrodynamic extrusion printing apparatus including a controller configured to produce any one or more of the claimed or otherwise described electrohydrodynamic extrusion printing steps.

[0012] In some embodiments, the electrohydrodynamic ejection printing apparatus may include a nozzle with a tip having an opening in diameter between approximately 50 nm and 5000 nm, an ink reservoir fluidly connected to the nozzle, a substrate support for supporting the substrate during printing, and a power supply configured to apply a potential between the nozzle and the substrate support, or between the nozzle and the substrate.

[0013] Another embodiment of the disclosed features provides an electroplating apparatus including a controller configured to produce any one or more of the electroplating steps claimed or otherwise described herein.

[0014] In some embodiments, the electroplating apparatus includes a chamber for holding an electrolyte, a substrate holder configured to hold a substrate during electroplating, an anode, and a power supply configured to apply a potential between the anode and the substrate during electroplating.

[0015] In another embodiment of the disclosed features, a system for processing a substrate is provided, comprising an electrohydrodynamic ejection printing apparatus as claimed or otherwise described herein, an electroplating apparatus, and a controller configured to produce any one or more electroplating steps.

[0016] In other embodiments of the disclosed models, a system is provided for processing a substrate, the system comprising an electrohydrodynamic ejection printer including a nozzle having an opening with a diameter between approximately 50 nm and 5000 nm, an ink reservoir fluidly connected to the nozzle, a substrate support for supporting the substrate during printing, and a power supply configured to apply a potential between the nozzle and the substrate support or between the nozzle and the substrate; an electroplating apparatus including a chamber for holding an electrolyte, a substrate holder configured to hold the substrate during electroplating, an anode, and a power supply configured to apply a potential between the anode and the substrate during electroplating; and a controller configured to print an ink comprising an electroplating additive comprising an accelerator or inhibitor dissolved in a solvent onto a substrate in a pattern using the electrohydrodynamic ejection printer, and after printing the ink onto the substrate, to electroplat a metal onto the substrate using the electroplating apparatus, wherein the electroplating is performed by preferential deposition, providing a first deposition rate where the electroplating additive obtained from the ink is present and a second deposition rate where the electroplating additive obtained from the ink is not present, the first deposition rate being different from the second deposition rate.

[0017] In various embodiments, the system may further include an apparatus configured to deposit a seed layer on a substrate. In certain embodiments, the system may further include a physical deposition apparatus configured to deposit a seed layer on a substrate. In certain configurations, the system may further include an electroless plating module configured to deposit a seed layer on a substrate. In certain embodiments, the system may further include an electroless plating activation module. In these or other embodiments, the controller may be configured to deposit a seed layer on the substrate before plating the ink onto the substrate.

[0018] In some implementations, the system further includes a chemical etching apparatus configured to remove metal from the substrate. In these or other embodiments, the controller may be configured to remove a portion of the electroplated metal on the substrate and a portion of the seed layer on the substrate. In some implementations, the electrohydrodynamic extrusion printing apparatus and the electroplating apparatus may be provided together in a single tool.

[0019] In other embodiments of the disclosed models, an electrohydrodynamic ejection printing ink is provided, comprising a solvent containing at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol, and an electroplating additive dissolved in the solvent, comprising accelerators and inhibitors, and present in the solvent at a concentration between approximately 0.1 g / L and 10 g / L.

[0020] In another embodiment of the disclosed features, an ink is provided for electrohydrodynamic extrusion printing, comprising an electroplating additive present at a concentration between about 0.1 g / L and 10 g / L and containing an accelerator or inhibitor, and a solvent having a vapor pressure of about 24 Torre or less at 25°C and a dielectric constant between about 40 and 90, and having a viscosity between about 0.7 cP and 20 cP, wherein the electroplating additive is completely dissolved in the solvent.

[0021] In some embodiments, the oxygen concentration in the ink is approximately 1 ppm or less. Oxygen may react with certain ink additives over time, thereby reducing the required concentration of the ink's most important electrochemically active compounds. In some embodiments, the ink may contain additional species that can react with and consume oxygen. The species that react with and consume oxygen may be present in a concentration sufficient to maintain the oxygen concentration in the ink at approximately 1 ppm or less. This may improve the ink's shelf life. In some embodiments, the species that react with and consume oxygen is a sulfite compound. One specific example is sodium sulfite. In some implementations, the electroplating additive in the ink includes an accelerator. In some other implementations, the electroplating additive in the ink includes an inhibitor. In some embodiments, the solvent may include at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol. In some embodiments, the solvent is an organic substance. In these or other embodiments, the solvent may have a natural boiling point between approximately 95°C and 275°C. In these or other embodiments, the solvent may comprise a first co-solvent and a second co-solvent. In these and other embodiments, the solvent may comprise a wetting agent. The wetting agent reduces the feeding angle between the ink and the seed layer. The wetting agent may prevent discontinuous or drop-like printing. In these and other embodiments, the ink may comprise a salt.

[0022] These and other aspects will be further described below with reference to the drawings. [Brief explanation of the drawing]

[0023] [Figure 1A] This flowchart describes a method for forming metallic features using photoresist-based techniques.

[0024] [Figure 1B] Figure 1A depicts various parts of the processing equipment used to carry out the method shown.

[0025] [Figure 2A] A flowchart describing a method of forming a metal feature according to an embodiment of this specification.

[0026] [Figure 2B] Illustrate the processing equipment used to perform the method of Figure 2A.

[0027] [Figure 3A] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an accelerator ink in an electrohydrodynamic ejection printing process. [Figure 3B] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an accelerator ink in an electrohydrodynamic ejection printing process. [Figure 3C] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an accelerator ink in an electrohydrodynamic ejection printing process. [Figure 3D] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an accelerator ink in an electrohydrodynamic ejection printing process.

[0028] [Figure 4A] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an inhibitor ink in an electrohydrodynamic ejection printing process. [Figure 4B] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an inhibitor ink in an electrohydrodynamic ejection printing process. [Figure 4C] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an inhibitor ink in an electrohydrodynamic ejection printing process. [Figure 4D] Depict a semiconductor substrate partially fabricated when undergoing the method of Figure 2A using an inhibitor ink in an electrohydrodynamic ejection printing process.

[0029] [Figure 5]A close-up view of the nozzle and substrate during electrohydrodynamic extrusion printing, according to one embodiment, is provided.

[0030] [Figure 6] An electroplating cell according to a certain embodiment is depicted.

[0031] [Figure 7] Examples of electroplating tools having numerous electroplating cells and other features according to certain embodiments are provided.

[0032] [Figure 8] This document describes a number of electroplating cells and electroplating tools having other features according to certain embodiments.

[0033] [Figure 9A] An example of a semiconductor substrate partially fabricated during multilayer lamination is provided, according to a certain embodiment. [Figure 9B] An example of a semiconductor substrate partially fabricated during multilayer lamination is provided, according to a certain embodiment. [Figure 9C] An example of a semiconductor substrate partially fabricated during multilayer lamination is provided, according to a certain embodiment. [Figure 9D] An example of a semiconductor substrate partially fabricated during multilayer lamination is provided, according to a certain embodiment. [Modes for carrying out the invention]

[0034] The following description includes numerous specific details to enable a full understanding of the embodiments presented. The disclosed embodiments may be implemented without some or all of these specific details. In other examples, well-known processing operations are not described in detail to avoid unnecessarily obscuring the disclosed embodiments. While the disclosed embodiments are described in relation to specific embodiments, it should be understood that they are not intended to be limiting.

[0035] Figure 1A is a flowchart describing a series of steps for forming fine wire interconnects, pads, or other metallic features on a substrate according to a conventional method. Figure 1B depicts various parts of a semiconductor processing apparatus used to carry out method 100 described in Figure 1A. The steps shown in Figure 1A are described in relation to the apparatus shown in Figure 1B.

[0036] In Figure 1A, method 100 begins with operation 101, in which a conductive seed layer is deposited on the substrate. This deposition is carried out in a physical deposition apparatus 150 shown in Figure 1B. Next, the substrate is transferred to a photoresist deposition apparatus 152, and in operation 103, a photoresist layer is formed on the seed layer. The photoresist may be formed by a wet process such as spin coating, or by a dry process, for example, by applying a roll of pre-formed photoresist material over the entire surface of the substrate.

[0037] After forming the photoresist layer, the substrate is transferred to a photoresist pattern forming apparatus 154, where, in operation 105, the photoresist layer is patterned by exposure to specific light conditions. Further in operation 105, the substrate is transferred to a photoresist developing apparatus 155, where the exposed pattern on the substrate is developed. In one example, the photoresist is developed by a wet chemical treatment involving a step of exposing the substrate to an aqueous solution containing a dissolved salt, such as an aqueous solution of potassium carbonate. These pattern forming processes also result in the formation of concave features within the photoresist layer. These concave features define spaces for later metal deposition.

[0038] Next, the substrate is transferred to the plasma etching apparatus 156, and in operation 107, a scum removal process is performed to remove excess photoresist material from the bottom of the feature. The scum removal process typically involves exposure to an oxygen-containing plasma that acts to heat and remove excess photoresist at the bottom of the feature.

[0039] Next, the substrate is transferred to the electroplating apparatus 158, and in operation 109, a metal is plated (for example, by electroplating or electroless plating) into the defined features in the photoresist layer. Then the substrate is transferred to the photoresist stripping apparatus 160, and in operation 111, the photoresist layer is stripped from the substrate. The photoresist layer may be stripped by a dry plasma etching technique (for example, by exposing the substrate to an oxygen-containing plasma) or by a wet technique (for example, by exposing the substrate to a photoresist solvent to dissolve or expand the photoresist film, after which the photoresist may be removed by high-flow, ultrasonic energy, or other methods). After the photoresist layer has been removed, the substrate is transferred to the chemical etching apparatus 162, and in operation 113, the seed layer is removed in the areas previously protected by the photoresist layer.

[0040] In many cases, each of the devices shown in Figure 1B is a separate device, each configured to perform a specific operation in the process flow described in Figure 1A. Together, Figures 1A and 1B illustrate that conventional process flows for forming metal coating features, such as fine wire interconnects, are complex, time-consuming, and costly. They require many different specialized semiconductor processing devices, each of which must be appropriately configured for a specific application. The large number of steps and devices associated with conventional process flows makes it difficult to make arbitrary changes or adjustments to the substrate processing technique (including, for example, substrate design and layout), as every process and part of the equipment must be appropriately coordinated. This makes it difficult to switch between manufacturing one type or design of substrate and another. Similarly, the complex process flow and the numerous devices involved make it difficult to test or create prototype substrates.

[0041] The techniques described herein enable the formation of fine wire interconnects, pads, and other similar metal coating features without requiring many of the processes and apparatus described in Figures 1A and 1B. As a result, the manufacturing process is significantly simplified (for example, because fewer steps are involved, and a substantial portion of the processing costs are directly related to the capital costs of acquiring the processing equipment), the number of processing devices is substantially reduced, and the costs associated with the processing are similarly reduced.

[0042] Figure 2A is a flowchart describing a method for forming a fine wire interconnect or similar metal coating feature according to embodiments of this specification. Figure 2B depicts the processing equipment used to carry out method 200 of Figure 2A. The steps shown in Figure 2A will be described in relation to the apparatus shown in Figure 2B.

[0043] In Figure 2A, method 200 begins with operation 201, in which a conductive seed layer is formed on a substrate in a seed layer deposition apparatus 250. In some cases, the seed layer may be formed by physical vapor deposition in a physical vapor deposition apparatus. As known in the prior art, the seed layer may also be formed by other methods, such as electroless plating. In some embodiments, electroless plating begins with an electroless activation step (which may involve, for example, a step of exposing the substrate to tin ions), followed by tin(II) to tin(IV) substitution / activation using a palladium ion-containing electrolyte. This leaves a substrate surface with a palladium electrocatalyst on top, allowing many dielectric materials to be coated with metal. In some cases, electroless plating may be carried out via a solution containing a reducing agent and metal ions of the metal to be plated as the seed layer. Examples of reducing agents suitable for use when creating a copper seed layer include dimethylamine borane (DMAB) and potassium hypophosphate.

[0044] In various embodiments, the substrate may be optionally pre-treated after the seed layer is formed in operation 201 and before electrohydrodynamic extrusion printing in operation 203. This pre-treatment may be performed to remove surface oxides on the seed layer. The pre-treatment may be performed wet or dry. For example, the wet treatment may involve applying a dilute acid such as H2SO4 or a reducing agent such as dimethylamine borane (DMAB) to the substrate. The dry treatment may involve heating the substrate to a temperature of about 100°C to 200°C in a reducing atmosphere such as a foaming gas. Such pre-treatment may be particularly beneficial in embodiments in which the substrate is exposed to atmospheric conditions (or other oxygen-containing environments) after the seed layer is deposited in operation 201 and before electrohydrodynamic extrusion printing in operation 203.

[0045] Regardless of the specific method used to form the seed layer and optionally pre-treat it, the substrate is provided to the electrohydrodynamic extrusion printing apparatus 252, and in operation 203, ink is selectively printed onto the substrate by electrohydrodynamic extrusion printing. The ink is an electrochemically active ink, as further described below. While other methods can be used to deposit ink onto a substrate, electrohydrodynamic extrusion printing is particularly well-suited for applications requiring high-resolution liquid transitions, specifically for semiconductor interconnect and packaging applications where critical dimensions of lines, spaces, and structures are generally smaller than about 50 μm, more commonly less than 10 μm, or even less than 2 μm.

[0046] The selective deposition of electrochemically active inks using electrohydrodynamic extrusion printing processes also involves the development of an ink having suitable properties for storage, transport, and delivery to a substrate surface, and having activating chemical components with appropriate solubility, such as suitable solvents and active chemicals that function in this process. In various embodiments herein, the ink comprises one or more plating additives dissolved in a solvent. Examples of plating additives include accelerators and inhibitors, which are discussed further below. Suitable solvents and other types that may be present in the ink are also discussed further below.

[0047] After the ink dries on the substrate surface, the plating additives and any other non-volatile substances in the ink remain on the substrate surface. At this point, the substrate may optionally be rinsed with, for example, deionized water. While we do not wish to be bound by any particular model or theory, it is considered most effective for the functionally useful plating additives according to the embodiments herein to remain in the printed location if they chemically react with the metal seed layer of the substrate and become strongly adhered to the surface and immobilized. In other words, the plating additives may react with the seed layer on the substrate and chemically bond to the seed layer. As one class, thiol-terminated (e.g., RSH-terminated) mercatol compounds are examples of materials that bond to the copper seed layer (and some other seed layers or other surfaces) and exhibit the desired immobilization properties. Specific examples of compounds in this class include mercaptopropanesulfonic acid (which may, for example, act as an accelerator) and mercaptohexanol (which may, for example, act as an inhibitor). Another example of a class of strongly metal-bonded compounds is triazoles. Benzotriazole is an example of a useful triazole that may act as an inhibitor. Benzotriazole-5-sulfonic acid and benzotriazole-5-carboxylate are examples of triazoles that may act as accelerators. After rinsing, the substrate may be subjected to centrifugal dehydration or another drying method to remove any undesirable materials. Rinsing may remove plating additives and some or all of the non-volatile materials resulting from the ink. Much or all of the plating additives should remain on the substrate surface after optional rinsing as a result of the immobilization described above, for example.

[0048] Next, the substrate is transferred to the electroplating apparatus 254, and in operation 205, a metal is electroplated onto the substrate to form features by preferential deposition. Since the ink contains at least one plating additive that promotes (e.g., an accelerator) or delays (e.g., an inhibitor) the plating in areas where the ink / plating additive is absent, the deposition process is preferential.

[0049] In practice, in cases where the ink contains a plating accelerator, areas of the substrate where the ink is present undergo preferential electroplating compared to areas of the substrate where the ink is absent. Conversely, in cases where the ink contains a plating inhibitor, areas of the substrate where the ink is absent undergo preferential electroplating compared to areas of the substrate where the ink is present. Each of these examples will be further described below in relation to Figures 3A-3D and 4A-4D. In either case, some amount (e.g., a non-zero amount) of deposition may occur in both the printed and unprinted areas of the substrate. However, the different deposition rates achieved in the printed areas compared to the unprinted areas result in the growth of patterned features. Features are positioned in areas that experience faster metallic deposition rates. In other words, as used herein, the term “feature” is intended to refer to positive / raised features rather than negative / concave features unless otherwise specified.

[0050] After electroplating the metal by a preferential deposition process, the substrate is transferred to a chemical etching apparatus 256, and in operation 207, the substrate is chemically etched to remove excess plated metal and seed layers. The plated metal may be partially removed in areas where features are present. The plated metal and seed layers may be substantially or completely removed in areas between features (compared to areas where features are present) before etching, as these areas have relatively less metal. These etchings act to spatially and electrochemically isolate the metallic features from each other.

[0051] Various parts of the processing equipment may be combined in various ways. In one example, the system includes a physical vapor deposition apparatus, an electrohydrodynamic extrusion printing apparatus, an electroplating apparatus, and a chemical etching apparatus, each of which is separate and isolated from one another. In another embodiment, one or more of the apparatus shown in Figure 2B may be provided in the form of modules of a larger apparatus that performs multiple processes. For example, the physical vapor deposition apparatus may be a separate apparatus, while liquid-based atmospheric processing apparatuses such as the electrohydrodynamic extrusion printing apparatus, electroplating apparatus, and chemical etching apparatus may be provided as modules within an integrated processing apparatus. In another example, the physical vapor deposition apparatus and the chemical etching apparatus are separate and isolated apparatuses, while the electrohydrodynamic extrusion printing apparatus and the electroplating apparatus are provided as modules within a larger integrated processing apparatus. In yet another example, the chemical etching apparatus is a separate and isolated apparatus, while the physical vapor deposition apparatus, electrohydrodynamic extrusion printing apparatus, and electroplating apparatus are provided as modules within a larger integrated processing apparatus. In another example, the physical vapor deposition apparatus and the electrohydrodynamic extrusion printing apparatus are each provided as modules within a larger, integrated processing unit, while the electroplating apparatus and the chemical etching apparatus are provided as separate, distinct processing units, or together as a second integrated processing unit. In yet another embodiment, one or more of the physical vapor deposition apparatus and / or electroplating apparatus may be modified to include hardware for performing electrohydrodynamic extrusion printing. If the electroplating apparatus is modified to include hardware for performing electrohydrodynamic extrusion printing, care should be taken to ensure that the inks used in the electrohydrodynamic extrusion printing process do not contaminate the electroplating solution. Movable baffles or other containment hardware may be provided. Many configurations consisting of the apparatus shown in Figure 2B are possible, and any such combination is considered to fall within the scope of the embodiments herein.The tools configured in this way may consist of linear, multi-level, carousel, conveyor, cluster, or other common tool designs, and the number of modules per processing type can be substantially 2 or more (e.g., 10), in which case the mixing ratio of the number of each type of processing modules operating in parallel is optimized based on the tool's productivity / output.

[0052] Figures 3A to 3D depict a partially fabricated semiconductor substrate according to one embodiment, where features are formed on top. In the embodiments of Figures 3A to 3D, the ink used in the electrohydrodynamic extrusion printing process contains an electroplating accelerator. Therefore, the ink in this example is called “accelerator ink”. Figures 3A to 3D are described in relation to the operation and apparatus described in Figures 2A and 2B. Figure 3A depicts a substrate 300 with a seed layer 301 on top. In a particular example, many different substrates and materials may be used, but the substrate 300 contains a layer of silicon dioxide across the entire surface of the silicon wafer. The seed layer 301 contains a conductive material such as copper, tantalum, or a combination thereof. In another example, the seed layer 301 contains nickel. Various materials and combinations of materials may be used for the seed layer. In certain cases where the seed layer 301 contains a certain combination of materials, the top exposed portion of the seed layer is the same metal as the metal structure to be plated (e.g., copper seed for conductors), however, this requirement is not always applicable. Generally speaking, the exposed surface of the seed layer 301 should be a metal that can be electroplated in aqueous solution when using aqueous plating (for example, a nickel seed layer can be used to plate a wire, but the exposed surface of a metal that is generally not platable due to an inhibitory oxidative surface layer such as W, Ta, or Ti cannot be plated). Referring to Figures 2A and 2B, the seed layer 301 may be formed in operation 201 in a seed layer deposition apparatus 250 (for example, a physical vapor deposition apparatus or an electroless deposition apparatus in some cases). After providing the seed layer 301, an accelerator ink 302 is printed on the seed layer 301 as shown in Figure 3B. This printing may be achieved in operation 203 in an electrohydrodynamic extrusion printing apparatus 252. The accelerator ink 302 is printed in a pattern that matches the pattern of the desired metallic features.

[0053] After printing the accelerator ink 302 onto the seed layer 301, metal 303 is electroplated onto both the seed layer 301 and the accelerator ink 302. This electroplating is performed in operation 205 within the electroplating apparatus 254. The metal 303 forms across the entire surface of both the printed and unprinted areas, as shown in Figure 3C, but grows more rapidly and therefore more extensively across the entire surface of the area printed with the accelerator ink 302. In effect, the presence of the accelerator in the accelerator ink 302, along with optional additional plating additives in the electroplating solution (e.g., inhibitors that slow the relative plating rate in the unprinted areas, and optional levelers), acts to promote a faster electroplating rate in the printed areas compared to the unprinted areas. In this example, metal 303 is preferentially plated three times faster in the printed areas than in the unprinted areas. In many embodiments of this specification, metal 303 is preferentially plated at least four times faster, or at least ten times faster, or at least twenty times faster in the printed areas than in the unprinted areas. The relative deposition rate depends on factors such as the concentration of additives deposited by printing, the applied voltage or total current, temperature, the selection of acid and / or copper concentrations, and the chemical identity of any selected plating additives (e.g., inhibitors and / or levelers) in the plating electrolyte. As a result of the different deposition rates, the pattern provided by the accelerator ink 302 is transferred to the metal 303. After electroplating, the substrate 300 is transferred to a chemical etching apparatus 256 and, in operation 207, undergoes chemical etching to remove portions of the metal 303 and seed layer 301, as shown in Figure 3D. Specifically, the substrate 300 is etched to such an extent that both the metal 303 and seed layer 301 are completely removed in the non-printed areas (e.g., areas where accelerator ink 302 is not present), while they remain in the printed areas (e.g., areas where accelerator ink 302 is present). Reference numeral 303d in Figure 3D represents the metallic features remaining on the substrate 300 after chemical etching in operation 207. After this etching operation, the metallic features 303d are spatially and electrochemically isolated from each other.

[0054] Figures 4A to 4D depict a partially fabricated semiconductor substrate with features formed on top, according to another embodiment. In the embodiments of Figures 4A to 4D, the ink used in the electrohydrodynamic extrusion printing process includes an electroplating inhibitor. Therefore, the ink in this example is called the “inhibitor ink”. Figures 4A to 4D are described in relation to the operation and apparatus described in Figures 2A and 2B. Figure 4A depicts a substrate 400 with a seed layer 401 on top. The seed layer 401 is similar to the seed layer 301 in Figure 3A. The seed layer 401 may be formed in a seed layer deposition apparatus 250 in operation 201. After providing the seed layer 401, the inhibitor ink 402 is printed on the seed layer 401, as shown in Figure 4B. This printing may be achieved in an electrohydrodynamic extrusion printing apparatus 252 in operation 203. The inhibitor ink 402 is printed in a pattern that matches the reverse of the pattern of the desired metallic features. In other words, the inhibitor ink 402 is provided in areas where metallic features are not desired.

[0055] After printing the inhibitor ink 402 onto the seed layer 401, metal 403 is electroplated onto both the seed layer 401 and the inhibitor ink 402. This metal plating is performed in operation 205 within the electroplating apparatus 254. The metal 403 forms across the entire surface of both the printed and unprinted areas as shown in Figure 4C, but grows more rapidly and therefore more extensively across the entire surface of the areas where the inhibitor ink 402 is absent. In effect, the plating inhibitor present in the inhibitor ink 402, along with additional plating additives in the electroplating solution (e.g., accelerators, as well as optionally selected inhibitors and / or levelers), acts to promote a faster electroplating rate in the unprinted areas compared to the printed areas. In this example, metal 403 is preferentially plated three times faster in the unprinted areas than in the printed areas. In many embodiments herein, metal 403 is preferentially plated at least four times faster, or at least ten times faster, or at least twenty times faster in the unprinted areas than in the printed areas. As noted in relation to Figures 3A to 3D, the relative deposition rate depends on factors such as the concentration of additives deposited by printing, the applied voltage or total current, the temperature, the choice of acid and / or copper concentrations, and the chemical identity of any selected plating additives (e.g., accelerators, inhibitors, and / or levelers) in the plating electrolyte. As a result of the different deposition rates, the reverse of the pattern provided by the inhibitor ink 402 is transferred to the metal 403. After electroplating, the substrate 400 is transferred to a chemical etching apparatus 256 and, in operation 207, undergoes chemical etching to remove portions of the metal 403, inhibitor ink 402, and seed layer 401, as shown in Figure 4D. Specifically, the substrate 400 is etched to such an extent that the metal 403, inhibitor ink 402, and seed layer 401 are completely removed in the printed areas (e.g., areas where the inhibitor ink 402 is present), while still remaining in the non-printed areas (e.g., areas where the inhibitor ink 402 is not present). In Figure 4D, reference numeral 403d represents the metallic feature remaining on the substrate 400 after chemical etching in operation 207. After this etching operation, the metallic features 403d are spatially and electrochemically isolated from each other.

[0056] Figures 9A to 9D show examples of process flows that may be used in certain embodiments. The process flows in Figures 9A to 9D may be combined with the process flows shown in Figures 3A to 3D and Figures 4A to 4D. In other words, these process flows may be used after preferentially electroplating features with an electrochemically active ink (e.g., an accelerator ink or an inhibitor ink). The embodiments shown in Figures 9A to 9D enable the formation of laminates containing different types of metals. Such embodiments may be particularly useful in situations where the formed features contain layers of different metals. One example of such a situation is the formation of interconnection columns, which may include metallic features having a diffusion barrier and a solder layer on top of it. In a particular example, the metallic feature is copper, the diffusion barrier is nickel, and the solder is tin or tin-silver. Another example of such a situation is the formation of relatively wide but thin electrical connection pads. In various embodiments, the formed laminate may contain any combination of copper, nickel, tin, indium, silver, gold, etc.

[0057] The substrate 900 begins as shown in Figure 9A. The substrate 900 includes a seed layer 901 positioned across the entire surface of the adhesive barrier layer 911. The seed layer 901 is similar to other seed layers described herein. The adhesive barrier layer 911 may contain materials such as tungsten, titanium, tantalum, titanium-tungsten, and tantalum-tungsten. The metal 903 is electroplated onto the seed layer to form raised features. Using the techniques described herein, for example, this electroplating may be performed using an electrohydrodynamic extrusion printing apparatus 252 to provide an electrochemically active ink on the surface of the substrate, followed by preferential electroplating in an electroplating apparatus 254 to form raised features. Although Figures 9A–9D do not depict ink, it is understood that such dried ink may be present between the seed layer 901 and the metal 903, as described and illustrated in relation to Figures 3C and 4C. Furthermore, although Figure 9A does not show any metal 903 between adjacent features, it is understood that such metals may be present, as shown in Figures 3C and 4C.

[0058] After plating the seed layer 901 with metal 903, the substrate 900 is transferred to an etching chamber such as the chemical etching apparatus 256 shown in Figure 2B. In this case, the seed layer 901 and metal 903 are etched to remove the seed layer 901 in the exposed area, as shown in Figure 9B. This etching is similar to the chemical etching operation 207 in Figure 2A. The etching process is selective and aims to remove the exposed seed layer 901 while leaving the adhesive barrier layer 911 substantially intact.

[0059] Next, the substrate is returned to the electroplating apparatus 254 and the diffusion barrier layer 912 is selectively plated onto the metal 903 without substantially depositing it on the adhesive barrier layer 911, as shown in Figure 9C. It is understood that, for example, at the corners where the seed layer 901 / metal 903 is in contact with the adhesive barrier layer 911, some amount of the diffusion barrier layer 912 may be formed on the adhesive barrier layer 911. For this application, such deposition is not considered essential. Furthermore, it is understood that such deposition occurs solely due to the presence of the seed layer 901 / metal 903, and that the diffusion barrier layer 912 does not form on the adhesive barrier layer 911 in locations where it is removed from the features formed by the seed layer 901 / metal 903.

[0060] Nickel is one example of a material for the diffusion barrier layer, but other materials may be used as desired. Without wishing to be bound by action theory or mechanism, it is assumed that the diffusion barrier layer 912 will not form on the adhesion barrier layer 911 because the adhesion barrier layer 911 becomes oxidized after the seed layer 901 is removed and the adhesion barrier layer 911 is exposed to oxygen / moisture. Such exposure to oxygen / moisture may occur when transferring the substrate between the etching chamber and the electroplating chamber. The oxidized material of the adhesion barrier layer 911 greatly inhibits the direct nucleation and growth of the plated metal, meaning that the metal (e.g., the diffusion barrier layer 912) will not be plated on the oxidized material. Furthermore, although the top exposed surface of the adhesion barrier layer 911 becomes oxidized, the adhesion barrier layer 911 still provides some electrical connectivity between adjacent features made of metal 903, and as a result, further electroplating is possible on the metal 903. Thus, when plated, the diffusion barrier layer 912 selectively deposits on the metal 903 without depositing on the adhesion barrier layer 911. The diffusion barrier layer 912 is deposited on all exposed sides of the metal 903 (and also on the exposed portion of the seed layer 901 that is still present beneath the metal 903).

[0061] Next, as shown in Figure 9D, a solder layer 913 is selectively deposited on the diffusion barrier layer 912 without substantially depositing on the adhesive barrier layer 911. This deposition is selective for the same reasons as described above with respect to the deposition of the diffusion barrier layer 912. The feature shown in Figure 9D may be, for example, a solder-coated column or connecting pad. Specific structures and materials described with respect to Figures 9A to 9D are provided for the purpose of illustrating the formation of features including layers of different metals. This embodiment is not intended to limit itself to the specific structures or materials described in this section. Any combination of the metals described herein may be included, and a variety of structures and materials may be formed as desired for specific applications.

[0062] Electrohydrodynamic extrusion printing (EPF) can be used to create extremely fine, small-scale patterns that were previously unattainable with alternative printing methods such as inkjet printing. For example, inkjet printing can produce features such as dots with a small diameter of approximately 50 μm to 100 μm. In comparison, EFFECTS can be used to form dots, lines, or other features with dimensions of <0.5 μm. If larger features are desired, EFFECTS can be used to form larger features with very high precision, for example, at a resolution of <0.5 μm. In other words, EFFECTS is useful not only for forming extremely small-scale features but also for forming somewhat larger features with high precision. The principle of EFFECTS is explained with reference to Figure 5.

[0063] Figure 5 illustrates a substrate 500 during electrohydrodynamic extrusion printing. The nozzle 501 is filled with ink 502. Furthermore, the nozzle 501 is fluidly connected to an ink reservoir (not shown) that supplies ink 502 into the nozzle 501 as needed. The nozzle tip 503 is at the bottom of the nozzle 501. The nozzle tip 503 is brought close to the substrate 500. When a large potential 504 is applied between the nozzle 501 and the substrate 500, the dipole moments of the solvent molecules inside the ink 502 are reoriented relative to the surface of the substrate 500, resulting in the creation of a liquid-phase surface space charge with the opposite sign to that of the substrate surface. This pulls the ink 502 toward the surface of the substrate 500, forming a Taylor cone at the nozzle tip 503, from which the ink 502 is finally discharged as an ink droplet 505. The ink droplet 505 contains residual charge and is accelerated toward the surface of the substrate 500 in an electric field created by the potential 504. Upon impact with the surface of the substrate 500, the charge within the ink droplet 505 is neutralized. As a result of the fluid flowing from this droplet, an electric current intermittently flows through the “circuit” created between the nozzle 501 and the substrate 500. After impacting the substrate 500, the solvent within the ink droplet 505 dries, leaving behind any non-volatile substances in the ink 502. In various embodiments of this specification, such non-volatile substances may be electroplating additives such as accelerators or inhibitors.

[0064] Although Figure 5 shows only a single nozzle, it will be understood that the electrohydrodynamic ejection printing process may utilize a number of independently controllable noises provided in rows, columns, arrays, or other configurations. Each of such nozzles can be independently biased to cause the nozzle to eject particles as desired or to not eject them. Furthermore, the nozzles and substrates may move relative to each other so that the substrate and each nozzle can interact at various locations as desired. In some cases, the nozzles are movable. In other cases, the substrate (e.g., a substrate support) is movable. In yet another case, both the nozzles and the substrate are movable. Figure 5 shows the nozzle 501 as a relatively elongated shaft projecting downward, but other nozzle designs may also be used. In another embodiment, the nozzle for delivering ink may be simpler and include, for example, an opening fluidly connected to an ink reservoir. In such an embodiment, the opening is analogous to the opening at the nozzle tip 503. As used herein, the terms opening and aperture are used interchangeably unless otherwise noted.

[0065] In certain embodiments, the width of the nozzle tip 503 opening may be between approximately 50 nm and 5000 nm. In many cases, the droplet size is one-third of the nozzle tip opening. In practice, a nozzle tip opening with a diameter of approximately 300 nm may be used to form droplets with a diameter of approximately 100 nm. Generally, the width of the nozzle tip opening should be relatively small to print small-scale features. In many examples, nozzle widths within the above range may be used to produce ink droplets with a diameter on the order of approximately 20 nm to 1500 nm. Using droplet sizes within this range, patterns (and ultimately plated metallic features) may be formed with extremely high resolution, for example, on the order of <0.5 μm. In certain mounting configurations, the distance 506 between the nozzle tip 503 and the surface of the substrate 500 may be between approximately 0.05 mm and 5 mm.

[0066] The apparatus may also include several other features not shown in Figure 5 that support the entire printing process, such as nozzle and / or substrate positioning equipment for adjusting the 3D position of the nozzle / printhead relative to a feature. In examples, the apparatus may include hardware for optical search and automatic guidance. Such hardware may be configured to detect origins on the wafer, thereby enabling precise alignment between the nozzle / printhead and the substrate, so that printing is performed at desired locations on the substrate relative to underlying structures on the substrate, notches and / or other origins on the substrate, and / or the edges of the substrate. The apparatus may include hardware (e.g., pumps, tubes, filters, etc.) for controlled delivery of printing ink from a bulk storage container to the nozzle head. The apparatus may include features that assist in simultaneously and independently positioning multiple nozzles within a multi-nozzle head. Several individual piezoelectric positioning devices may be provided, each capable of moving one or more nozzles of the multi-nozzle head assembly relative to each other, thereby enabling variable spacing of line-to-line parallel printing operations. The apparatus may include elements for controlling heat removal or addition, and elements for controlling the temperature of the ink, substrate, or both.

[0067] The apparatus may be designed so that the area above the print head and workpiece is substantially sealed (e.g., forming an environmental chamber), and as a result, the atmospheric environment in the space around the head, and / or the atmospheric environment in the space within the gap between the print head and the wafer, is controlled with respect to the temperature and / or gases present. For example, an environmental chamber may be used to remove undesirable gases (e.g., oxygen or moisture). In these or other examples, one or more gases (e.g., reactive or inert) may be added to the chamber to react with the ink or substrate, for example, to create an inert atmosphere (e.g., nitrogen, argon). In these or other examples, the apparatus may include hardware to adjust the atmosphere to contain a controlled amount of evaporated ink solvent and / or to perform printing under vacuum conditions (e.g., to assist the evaporation of the solvent). In these or other examples, the apparatus may have one or more FOUPs (front opening unified pods), which are sealed boxes designed to securely and safely hold the substrate in a controlled environment. The substrates may be removed from the FOUP by a tool equipped with a suitable load port and robotic handling system, as discussed below in relation to Figure 7, for example. The FOUP may be used to store incoming and / or outgoing substrates before and / or after processing them in the apparatus.

[0068] In some embodiments, the apparatus may include two or more modules operating in parallel with each other. Each module may be configured to provide, for example, electrohydrodynamic extrusion printing on a substrate surface, as described herein. Alternatively or in addition, one or more modules may be configured to perform other functions, as further described below in relation to Figures 7 and 8. Such other functions may include, but are not limited to, pre-treating the substrate before printing, rinsing the substrate after printing and before electroplating, drying the substrate after rinsing, and electroplating the substrate. In some examples, the module for pre-treating the substrate before printing may operate to remove surface oxides from the wafer. This removal may be achieved using a wet method in a wet pre-treatment station or using a dry method in a dry pre-treatment station. The wet method may involve the step of applying a dilute acid such as H2SO4 or a reducing agent such as dimethylamine borane (DMAB) to the substrate surface. The dry method may involve the step of heating the substrate in a reducing atmosphere such as a foaming gas (for example, at a temperature between about 100°C and 200°C). In various embodiments, the apparatus may include a system for holding and distributing wafers between different modules (e.g., a robotic handling system), as will be further discussed below in relation to Figures 7 and 8.

[0069] Other common device features may include fluid condition delivery control devices (e.g., heaters / coolers, heat exchangers, level controllers, etc.), as well as feedback control units for adjusting nozzle position (e.g., using current feedback where nozzle height is linked to electrohydrodynamic currents) and fluid delivery (e.g., using optical analysis of liquid film on a substrate). Furthermore, it is assumed that multi-channel power and / or power switching equipment would enable on-off control of an array of electrohydrodynamic ejection printheads to operate individually within a larger "printhead".

[0070] One factor that may be controlled during electrohydrodynamic ejection printing is the magnitude of the potential 504 (or, in relation to it, the current) applied between each of the one or more nozzles 501 and the substrate 500. When the electric field exceeds a certain limit, the stress from surface charge repulsion at the tip of the Taylor cone exceeds the surface tension, and the ink droplet 505 is ejected toward the substrate 500. The electric field potential 504 should be below the potential at which atomization of the ink in multiple directions or imperfectly controlled ink spraying occurs. In certain configurations, the magnitude of the potential 504 applied between the nozzle 501 and the substrate 500 may be between approximately 0.5kV and 10kV, or between approximately 1.5kV and 4kV. The magnitude of the potential may depend on several characteristics, including, for example, the identity and properties of the solvent in the ink 502, the identity and properties of the electroplating additives in the ink 502, the identity and properties of any additional species present in the ink 502 (if any), the distance 506 between the nozzle tip 503 and the substrate 500, and the size and resolution of the features in the printed pattern.

[0071] In various embodiments, the ink and / or ink droplets may have certain properties. In embodiments herein, the ink comprises at least one electroplating additive dissolved in a solvent. To ensure that the ink droplets reach the substrate surface, the ink droplets may have a certain size, and the solvent in the ink may have a certain volatility. In various embodiments, the droplet size may be at least about 20 nm, at least about 50 nm, or at least about 100 nm. In these or other examples, the droplet size may be about 1500 nm or less, about 1000 nm or less, about 400 nm or less, about 200 nm or less, about 100 nm or less, or about 50 nm or less. In some specific examples, the droplet size may be between about 20 nm and 1000 nm, or between about 100 nm and 400 nm. In these or other embodiments, the solvent present in the ink may have a standard boiling point between about 90°C and 275°C, or between about 100°C and 225°C. In certain cases, the solvent may have a standard boiling point of at least about 95°C, at least about 100°C, at least about 125°C, at least about 150°C, or at least about 175°C. In these or other embodiments, the solvent may have a standard boiling point of about 275°C or less, for example, about 225°C or less, or about 150°C or less. In these or other embodiments, the solvent present in the ink may have a vapor pressure of about 0.05 Torre to 30 Torre (for example, between about 6 Pa and 4000 Pa) or between about 0.1 Torre to 25 Torre (for example, between about 13 Pa and 3300 Pa) at 25°C. In many cases, the solvent may have a vapor pressure of about 23.8 Torre (for example, about 3175 Pa) or less at 25°C. Water has a vapor pressure of about 23.8 Torre (for example, about 3175 Pa) at 25°C. Therefore, in various embodiments, the solvent may have a vapor pressure of about 24 Torre or less (for example, about 3200 Pa or less) at 25°C. While vapor pressure is considered at 25°C, it is understood that solvents may be at different temperatures during use. More volatile solvents may dry out before reaching the substrate surface, at which point the free charge decomposes the solvent in the air. In that case, the pattern cannot be effectively printed on the substrate surface.Conversely, solvents that are not very volatile may not dry quickly enough when present on the substrate surface. In such cases, the ink may become blurry and wet outwards beyond the target dimensions of the desired pattern. In many cases, it is desirable for the droplets to dry completely within 100 ms of reaching the substrate surface.

[0072] Another consideration regarding the ink is that the solvent should adequately solubilize the electroplating additive. In many cases, the electroplating additive is a polar organic plating additive. In such cases, the solvent may also be polar, which can help solubilize the polar organic plating additive. An example of a polar organic plating additive that may be used is the accelerator mercatolpropanesulfonic acid. In some cases, the solvent may have a specific dielectric constant that can affect the solvent's ability to solubilize the plating additive. In certain cases, the solvent may have a dielectric constant between approximately 40 and 90, which is generally similar to the dielectric constant of water. Generally speaking, the solvent and the plating additive should have equivalent polarity.

[0073] Examples of solvents that meet the above criteria include water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, polypropylene glycol, and combinations thereof. These examples of solvents may also be combined with other solvents, provided that the volatility and solubility of the electroplating additives within the solvent remain within the guidelines provided above. In many cases, the solvent is organic and water-insoluble, but in some cases, water may be used. Examples of cosolvents that can be used to modify the viscosity, dielectric constant, and other properties of the underlying solvent to produce inks with target performance include dimethyl carbonate, diethyl carbonate, DMSO, and water. Other examples of cosolvents that may be used together include, but are not limited to, diethyl carbonate / propylene carbonate, dimethyl carbonate / propylene carbonate, diethyl carbonate / ethylene carbonate, and dimethyl carbonate / ethylene carbonate.

[0074] Another consideration regarding ink is its viscosity. Ink that is too viscous may be too difficult to handle and / or deliver to the print head, or too difficult to remove from the nozzle tip using a proper technique, while ink that is not viscous enough may quickly / easily become blurry before drying on the substrate surface. In certain mounting configurations, the ink may have an ambient temperature viscosity between approximately 0.7 cP and 20 cP (for example, at 20°C), more commonly between approximately 0.8 cP and 3 cP.

[0075] The electroplating additive may be provided within the ink at a specific concentration. In some embodiments, the electroplating additive may be provided at a concentration between about 0.01 g / L and 10 g / L (10 ppm and 10,000 ppm), or between about 0.1 g / L and 10 g / L, and in some cases between about 0.1 g / L and 1 g / L (about 100 ppm and 1,000 ppm). In some such implement liquids, the electroplating additive may be provided at a concentration of at least about 0.1 g / L (100 ppm), or at least about 0.15 g / L (150 ppm), or at least about 0.2 g / L (200 ppm). The ideal concentration of the electroplating additive for a particular application may depend on factors such as the identity and properties of the electroplating additive, the identity and properties of the solvent, and the composition of the electroplating solution used to later electroplat the metallic features. In various embodiments, the goal is to completely cover the surface to be moistened by the ink (e.g., a seed layer where the ink is to be printed) and to supply the ink with enough electroplating additives to react with the surface, and to form at least a single layer of adsorbed material. It is understood that the single layer is generally limited to the area where the ink is printed.

[0076] In addition to electroplating additives and solvents, the ink may contain one or more additional types. For example, in some examples, the ink may contain a wetting agent (e.g., a surfactant). When present, the wetting agent may alter the surface tension of the solvent, thereby affecting the size of the ink droplets and the resulting size and shape of the printed pattern and plated metallic features. The wetting agent may reduce the contact angle between the ink and the metal surface on which the ink is printed (e.g., a seed layer), thereby improving the wetting properties of the ink. The wetting agent may be a non-electrochemically active compound. In many cases, the wetting agent does not bond to the metal surface (e.g., a seed layer) and dissolves and detaches upon rinsing and / or comes into contact with the plating solution. Surfactants that may act as wetting agents include, for example, sodium lauryl sulfate, polypropylene glycol, or ethylene glycol, or oxides. In these and other examples, the ink may contain salts. When present, salts may alter the vapor pressure, viscosity, and other properties of the ink, thereby affecting the droplet size and the resulting printed pattern and plated metallic features. Examples of salts may include, for example, tetramethyl carbonate or tetraethyl carbonate, citrate, or hydroxides and copper sulfate. If the ink contains an accelerator, it may not contain an inhibitor and / or deterrent. Similarly, if the ink contains an inhibitor, it may not contain an accelerator. In some cases, for example, if a wetting agent is used in combination with an accelerator ink, and the wetting agent also happens to act as a plating inhibitor, the ink may contain both an accelerator and an inhibitor (e.g., a wetting agent). The interactions of electroplating additives during the electroplating process, as well as electroplating additives such as accelerators, inhibitors, and deterrents, will be discussed further below.

[0077] The ink may have a specific maximum oxygen concentration when delivered to the nozzle of an electrohydrodynamic ejection printing apparatus. In some cases, a degasser may be provided to ensure that the oxygen concentration in the ink remains below a maximum target concentration. The degasser may be connected to the ink reservoir or fluidly between the ink reservoir and the nozzle. In certain embodiments, the maximum oxygen concentration in the ink delivered to the nozzle is approximately 1 ppm. The oxygen level in the ink can also be controlled by including species that react with and consume oxygen within the ink itself, such as organic or inorganic sulfites. One specific example is sodium sulfite. The species that react with and consume oxygen may be provided in the ink at a concentration sufficient to maintain an oxygen concentration of approximately 1 ppm or less within the ink.

[0078] Another factor that can affect the electrohydrodynamic extrusion printing process is the printing temperature. For example, the ink temperature can affect the ink viscosity, which in turn can affect droplet size and the resulting printed pattern / plated features. Similarly, the substrate temperature can affect how quickly the ink dries. In various cases, the ink temperature, nozzle temperature, and / or the temperature of the substrate (or the support on which the substrate is positioned) may be controlled during printing. In practice, the ink and nozzle may be maintained at a temperature between approximately 100°C and 200°C during printing. In these and other cases, the temperature of the substrate or substrate support may be controlled during printing. For example, the substrate or substrate support may be maintained at a cooled or heated temperature depending on the properties of the particular solvent and ink. For example, the substrate and substrate support may be maintained at a temperature between approximately 100°C and 200°C during printing.

[0079] In some cases, the ink may be chemically stable so that it can be stored for a long period of time. In other cases, the ink may not be so chemically stable. In some such embodiments, the ink may be prepared at the desired concentration a short time before use (for example, within about a week before use, for example, within about three days before use, or within about 24 hours before use) by mixing the relevant components in the relevant solvent.

[0080] The substrate may also have certain properties. For example, in many cases the substrate is a silicon semiconductor wafer. Often the substrate has a layer of silicon oxide on it. Furthermore, the substrate typically includes a conductive seed layer that is exposed when supplied to an electrohydrodynamic extrusion printing apparatus, as shown in Figures 3A and 4A. The conductive seed layer is typically metallic and often includes copper, tantalum, nickel, or mixtures thereof. In some cases, other metals may also be used. The seed layer may have a thickness between approximately 50 Å and 2000 Å. After printing, in the electrohydrodynamic extrusion printing process, the dried ink may have a thickness between approximately 0.01 μm and 0.25 μm. After printing and before etching, the preferentially plated features may have a thickness between approximately 0.25 μm and 25 μm (measured, for example, as height). The thickness of the plated metal between the preferentially plated features (e.g., metal grown at a relatively slow rate) may be between approximately 0.05 μm and 2 μm (e.g., measured as height). As described in relation to Figures 3D and 4D, chemical etching may be used after electroplating to etch and remove (i) the desired metal between the preferentially plated features, (ii) the unwanted seed layer between the preferentially plated features, (iii) any unwanted ink, and (iv) the top layer of metal on the preferentially plated features. After etching, the preferentially plated metal features are spatially and electrochemically isolated from each other. The isolated features may have a height between approximately 0.20 μm and 20 μm.

[0081] As noted above, inks typically contain electroplating additives that act to promote different plating rates in the printed area compared to the non-printed area. In many cases, the additives are accelerators or inhibitors. If the ink contains an accelerator, the electroplating solution typically contains an inhibitor (and an optional leveler). If the ink contains an inhibitor, the electroplating solution typically contains an accelerator (and an optional leveler). However, in some cases, the electroplating solution may be without (or substantially without) accelerators, inhibitors, inhibitors, and / or levelers. In such cases, the electrolyte may contain a solvent (e.g., water), ions of the metal to be plated (e.g., copper ions for plating copper features), and an acid.

[0082] While we do not wish to be bound by any operating theory or mechanism, electroplating inhibitors such as polyethylene glycol, polyethylene oxide, polypropylene glycol, and polypropylene oxide (on their own or in combination with other electroplating solvents) are considered to be surface motion limiting (or polarization) compounds that cause a significant increase in voltage drop across the entire substrate-electrolyte interface, especially when present in combination with surface-adsorbed halides (e.g., chlorides or bromides). The halides may act as chemiadsorbed bridges between the inhibitor molecules and the substrate surface. The inhibitors not only (1) increase the local polarization of the substrate surface in areas where the inhibitor is present compared to areas where the inhibitor is absent, but also (2) increase the polarization of the substrate surface in general. The increase in polarization (local and / or overall) corresponds to an increase in resistivity / impedance, and therefore to slower plating at a particular applied potential.

[0083] Conventional plating inhibitors do not strongly adsorb or chemically adsorb onto the substrate surface and are not incorporated into the deposited film to a great extent, but are thought to degrade slowly over time due to electrolysis or chemical decomposition in the electroplating bath. Because conventional plating inhibitors do not strongly adsorb onto the substrate surface, these molecules generally do not produce the different plating rates described herein when provided in ink. Rather, conventional electroplating inhibitors provided in ink are likely to be washed away during rinsing or come into contact with the electroplating solution. Conventional electroplating inhibitors are often relatively large molecules and, in many examples, are essentially polymers (e.g., polyethylene oxide, polypropylene oxide, polyethylene glycol, polypropylene glycol, various copolymers, and mixtures thereof). Other examples of inhibitors include polyethylene oxide and polypropylene oxide with S- and / or N-containing functional groups, and block polymers of polyethylene oxide and polypropylene oxide. Inhibitors may have a linear structure, a branched structure, or both. It is common for inhibitor molecules of various molecular weights to coexist in commercially available inhibitor solutions. Unlike the inhibitors described herein (which may be used, for example, as polarizers in inhibitor inks), inhibitory molecules generally do not bind strongly to the surface and can be removed from the surface by rinsing, or they diffuse away from the surface and enter the plating solution when in contact with it. Therefore, inhibitory molecules, when used herein, are polarizers that bind relatively loosely to the surface and are not useful as inhibitors in principle in inhibitor inks. That said, inhibitors may be added to electrohydrodynamic extrusion printing inks for purposes other than producing different plating rates. In practice, some inhibitors also act as wetting agents / surfactants. Such inhibitors may be provided in electrohydrodynamic extrusion printing inks (e.g., accelerator inks or inhibitor inks) for the purpose of improving the wetting of the ink on the relevant seed layer. Inhibitors may also be present in the electroplating solution on which the substrate is plated after printing. Such inhibitors are particularly beneficial when the ink is an accelerator ink.

[0084] While we do not wish to be bound by any particular activity theory or mechanism, it is believed that accelerators (either alone or in combination with other solvents) tend to locally reduce the polarization effect associated with the presence of inhibitors, thereby locally increasing the electrodeposition rate. The reduced polarization effect is most pronounced in the areas where the adsorbed accelerator is most concentrated (i.e., polarization is reduced as a function of the local surface concentration of the adsorbed accelerator). Examples of accelerators include, but are not limited to, dimercatolpropanesulfonic acid, dimercatolethanesulfonic acid, mercaptopropanesulfonic acid, mercatoethanesulfonic acid, bis-(3-sulfopropyl) disulfide (SPS), and their derivatives. In various embodiments herein, the accelerator comprises an alkane chain with at least one mercapto group and at least one sulfonic acid group or salt. The accelerator may become strongly adsorbed to the substrate surface and, as a result of the printing process and / or printing reaction, generally do not move to the lateral surface but are generally not incorporated into the film to a great extent. As a result, the accelerator remains on the substrate for a considerable amount of time, allowing the metal to accumulate for a substantial amount of time to deposit.

[0085] For the purposes of this disclosure, the inhibitor (which may be present, for example, in an ink) is an electrochemically active compound that (i) reacts with the substrate surface so as to remain on the surface when the surface is rinsed or when the surface comes into contact with the electroplating solution, or so as to become fairly strongly adsorbed onto the substrate surface, and (ii) increases the polarization of the surface (or, in a similar sense, increases the charge transfer resistance or increases the voltage required to drive the same amount of current through the surface during plating).

[0086] In certain embodiments, levelers may be present in the ink and / or electroplating solution. While we do not wish to be bound by any theory or mechanism of action, levelers are considered to act as polarizers (either alone or in combination with other solvents). In some cases, levelers may replace, remove, or drive accelerators so as to be incorporated into the growing metal film, thereby counteracting the depolarization effect associated with the accelerator.

[0087] Levelers can locally increase the polarization / surface resistivity of the substrate, thereby slowing down local electrodeposition reactions in areas where levelers are present. A key attribute of levelers is that their local surface concentration is determined to some extent by mass transport; typically, levelers are continuously consumed within the growing plated film or converted into non-inhibitory byproducts as a result of contact with the surface and / or electrolytic reduction. Because they are consumed / converted in this way, a continuous supply of levelers is provided to the surface to maintain the desired leveler concentration. Levelers primarily act on surface structures that have geometric shapes that protrude away from the surface and are exposed to the solution environment. This action "smooths" the surface of the electrodeposited layer. Often, levelers react or are consumed at or near the diffusion limit rate on the substrate surface, and therefore, a continuous supply of levelers is often considered beneficial for maintaining uniform plating conditions over time. In certain packaging configurations, neither the ink nor the electroplating solution requires levelers (or, similarly, only trace amounts of levelers may be present).

[0088] Leveler compounds are generally classified as levelers based on their electrochemical function and effects, and do not require a specific chemical structure or formula. However, levelers often contain one or more nitrogens, amines, imides, or imidazoles, and may also contain sulfur functional groups. Certain levelers contain one or more five-membered and six-membered rings, and / or conjugated organic compound derivatives. Nitrogen groups may form part of a cyclic structure. In amine-containing levelers, the amine may be a primary, secondary, tertiary, or quaternary alkylamine or arylamine. Furthermore, the amine may be an arylamine or a heterocyclic amine. Examples of amines include, but are not limited to, dialkylamines, trialkylamines, arylalkylamines, triazoles, imidazoles, triazoles, tetrazoles, benzimidazoles, benzotriazoles, piperidines, morpholines, piperazines, pyridines, oxazoles, benzoxazoles, pyrimidines, quinolines, and isoquinolines. Imidazoles and pyridines may be particularly useful. Another example of a leveler is Janus Green B. Leveler compounds may also contain ethoxide groups. For example, a leveler may contain a general backbone similar to those found in polyethylene glycol or polyethylene oxide, with amine fragments functionally inserted throughout the entire chain (e.g., Janus Green B). Examples of epoxides include, but are not limited to, epihalohydrins such as epichlorohydrin or epibromohydrin, as well as polyepoxide compounds. Polyepoxide compounds having two or more epoxide moieties linked together by an ether-containing chain can be particularly useful. Some leveler compounds are polymers, while others are not. Examples of polymeric leveler compounds include, but are not limited to, polyethyleneimines, polyamidoamines, quaternized poly(vinylpyridine), and reaction products of various oxygen epoxides or sulfides with amines. An example of a nonpolymeric leveler and electroplating inhibitor compound is 6-mercaptohexanol.Similarly, many other organic thiol alcohols and compounds other than thiolsulfonic acid group-containing compounds act as leveling / plating inhibitors when adsorbed to surfaces. Another example of a suitable leveling agent is polyvinylpyrrolidone (PVP).

[0089] Generally speaking, accelerators increase the plating rate, while inhibitors, suppressants, and levelers decrease the plating rate. Levelers also function to reduce the plating rate, so certain levelers may be considered inhibitors for this application, assuming they meet the criteria for inhibitors. As discussed above, inhibitors are species that bind to the substrate surface (e.g., seed layer) and act to preferentially delay the plating reaction in the presence of the inhibitor, as opposed to the absence of the inhibitor. When using inhibitor inks, the localized plating inhibition resulting from the inhibitor in the inhibitor ink should persist long enough to produce a significant difference in plating during electroplating (e.g., a larger plated area without the inhibitor and a smaller plated area with the inhibitor).

[0090] The electrolyte used in electroplating processes may have specific properties. For example, the ink used in electrohydrodynamic extrusion printing processes contains an electroplating accelerator (e.g., an accelerator ink). Therefore, the electrolyte used in electroplating processes may not contain an accelerator (or may contain only a small amount of an accelerator). This ensures that the accelerator is adsorbed only on the substrate surface in the desired locations, for example, where the accelerator ink is printed and where metallic features are desired. In these cases, the electrolyte includes one or more other plating additives, such as an inhibitor and an optional leveler. An example of an inhibitor concentration may be between 10 ppm and 1000 ppm, and an example of a leveler concentration, if present, may be between approximately 0.1 ppm and 2 ppm. Furthermore, the electrolyte typically contains copper ions (e.g., obtained from copper sulfate or other sources) at a concentration between approximately 10 g / L and 60 g / L, an acid (e.g., sulfuric acid) at a concentration between approximately 5 g / L and 180 g / L, and halide ions (e.g., chloride, bromide, fluoride, etc.) at a concentration between approximately 30 ppm and 80 ppm. The halide ions may act to enhance the adsorption of inhibitor molecules on the substrate surface. In this example, an electric current is applied to the substrate during electroplating to deposit copper in both printed and unprinted areas, with preferential (e.g., larger) deposition occurring in areas where the inhibitor ink is present.

[0091] In another example, the ink used in an electrohydrodynamic extrusion printing process contains an electroplating inhibitor (e.g., inhibitor ink). Therefore, the electrolyte used in the electroplating process does not need to contain an inhibitor (or only needs to contain a very small amount of one). This ensures that the inhibitor is adsorbed only on the substrate surface where desired, for example, where the inhibitor ink is printed and where metallic features are not desired. In some embodiments, the plating solution used to electroplat the features may contain only an acid (e.g., sulfuric acid between approximately 5 g / L and 180 g / L) and cupric ions (e.g., between approximately 10 g / L and 60 g / L). However, depending on the relative surface adsorption strength between the inhibitor in the inhibitor ink and the accelerator used in the plating bath, one or more additional components such as accelerators, chloride ions, and inhibitors may be present in the plating bath to enhance significant differences in plating rates. Specifically, if the inhibitor is more strongly adsorbed and not replaced on the surface by the accelerator, the accelerator may be present in the plating solution and adsorbed in areas of the surface without the inhibitor. In these examples, the electrolyte may include one or more other plating additives, such as inhibitors and optionally levelers. Examples of accelerator concentrations may be between approximately 10 ppm and 1000 ppm, and examples of leveler concentrations, if present, may be between approximately 0.1 ppm and 2 ppm. Furthermore, the electrolyte typically contains copper ions (e.g., from copper sulfate or other sources) at a concentration between approximately 10 g / L and 60 g / L, an acid (e.g., sulfuric acid) at a concentration between approximately 5 g / L and 180 g / L, and halide ions (e.g., chlorides, bromides, fluorides, etc.) at a concentration between approximately 30 ppm and 80 ppm in various examples. In this example, an electric current is applied to the substrate during electroplating to deposit copper in both printed and unprinted areas, with preferential (e.g., larger) deposition occurring in areas where inhibitor ink is present.

[0092] In an alternative embodiment where the accelerator is adsorbed onto the substrate surface more weakly than the inhibitor is adsorbed onto the substrate surface, the inhibitor and accelerator, such as mercaptopropanesulfonic acid, on the substrate can be exposed to the entire surface after printing and before plating. In one example of this embodiment, after selectively printing the surface with an inhibitor ink, a solution containing 1 g / L of mercaptopropanesulfonic acid (or other accelerator) is sprayed onto the substrate surface while rotating the surface to expose the entire surface to the accelerator, or provided in other ways. While we do not wish to be bound to any particular model or theory, the accelerator is adsorbed onto areas of the metal surface that do not have an inhibitor, but the accelerator does not react with or replace the inhibitor where it is printed. The surface is then sprayed with the wafer to rinse the surface and then optionally dehydrated by centrifugal force. This leaves the surface with areas of adsorbed inhibitor obtained from the printing process and areas of adsorbed accelerator obtained from the spraying process. The areas of adsorbed inhibitor correspond to the areas printed with the inhibitor ink, while the areas of adsorbed accelerator correspond to the inverse of these areas of adsorbed inhibitor. Subsequently, by plating the surface in a plating solution (which does not require an accelerator), the difference in plating speed between the two areas becomes significantly higher.

[0093] The substrate may undergo a chemical etching process after electroplating to remove excess plated metal, ink, and seed layers, thereby spatially and electrically isolating individual metallic features as desired. The etching process may involve a step of bringing the substrate into contact with a chemical etching solution. The etching process proceeds for a duration sufficient to remove undesirable material, but not long enough to completely remove the desired metallic features.

[0094] Figure 6 shows an example of an electroplating cell in which electroplating may be performed. Often, an electroplating apparatus includes one or more electroplating cells in which a substrate (e.g., a wafer) is processed. For clarity, only one electroplating cell is shown in Figure 6. To optimize electroplating and ensure that the electroplating additives function over extended periods, the electroplating additives should not react with the anode. Therefore, the anode and cathode regions of the plating cell are sometimes separated by a film, allowing for the use of plating solutions of different compositions in each region. The plating solution in the cathode region is called the cathode solution, and the plating solution in the anode region is called the anodic solution. Electroplating additives may be restricted to the cathode to prevent undesirable reactions with the anode. Several engineering designs can be used to introduce anodic and cathode solutions into the plating apparatus.

[0095] Referring to Figure 6, a schematic cross-sectional view of an electroplating apparatus 601 according to one embodiment is shown. The plating tank 603 contains a plating solution (having a composition as provided herein) as indicated by a certain level 605. The cathode portion of this container is adapted to receive a substrate in the cathode. The wafer 607 is immersed in the plating solution and held by a clamshell substrate holder 609 mounted on a rotatable spindle 611 that allows the “clamshell” substrate holder 609 to rotate together with the wafer 607, for example. A general description of clamshell plating apparatuses suitable for use in the present invention is described in detail in U.S. Patent No. 6,156,167 granted to Patton et al. and U.S. Patent No. 6,800,187 granted to Reid et al.

[0096] The anode 613 is located below the wafer inside the plating tank 603 and is separated from the wafer area by a film 615, preferably an ion-selective film. For example, a Nafion® cationic exchange membrane (CEM) may be used. The area below the anode film is often called the “anode chamber.” The ion-selective anode film 615 enables ion transfer between the anode and cathode areas of the plating cell, while preventing particles generated at the anode from entering the vicinity of the wafer and contaminating it. The anode film is also useful for redistributing the flow of current during the plating process, thereby improving plating uniformity. Detailed descriptions of suitable anode films are provided in U.S. Patent Nos. 6,126,798 and 6,569,299, granted to Reid et al. Ion exchange films, such as cation exchange films, are particularly well-suited for these applications. These films are typically made from ionomer materials such as fully fluorinated copolymers containing sulfonic acid groups (e.g., Nafion®), sulfonated polyimides, and other materials known to those skilled in the art that are suitable for cation exchange. Selected examples of suitable Nafion® films include the N324 and N424 films available from Dupont de Nemours Co.

[0097] In some cases, convection and / or diffusion throughout the plating layer may be controlled. A typical method to aid diffusion is by the convection flow of the electroplating solution provided by the pump 617. In addition, wafer rotation may be used as well as vibrating or sonic stirring films. For example, a vibrating transducer 608 may be attached to a clamshell substrate holder 609. The pump 617 continuously supplies the plating solution to the plating tank 603. Generally, the plating solution flows upward to the center of the wafer 607 through the anode film 615 and diffusion plate 619, and then radially outward across the entire surface of the wafer 607. Furthermore, the plating solution may also be supplied into the anode area of ​​the tank from the side of the plating tank 603. The plating solution then overflows from the plating tank 603 and flows into the overflow reservoir 621. The plating solution is then filtered and returned to the pump 617 (not shown) to complete the recirculation of the plating solution. In certain plating cell configurations, a separate electrolyte is circulated through a portion of the plating cell containing the anode, while a moderately permeable or ion-selective membrane is used to prevent mixing with the main plating solution.

[0098] A reference electrode 631 is located outside the plating bath 603 in a separate chamber 633, which is replenished by overflow from the main plating bath 603. Alternatively, in some embodiments, the reference electrode is positioned as close as possible to the substrate surface, and the reference electrode chamber is connected to the side of the wafer substrate, or directly beneath it, via a capillary tube or by other means. In some preferred embodiments, the apparatus further includes contact sensing leads, which are connected to the periphery of the wafer and are configured to sense the potential of the metal seed layer around the wafer, but not to carry any current to the wafer.

[0099] A reference electrode 631 is typically employed when electroplating at a controlled potential is desired. The reference electrode 631 may be one of various commonly used types, such as mercury / mercury sulfate, silver chloride, saturated calomel, or copper metal. In some embodiments, in addition to the reference electrode, contact sensing leads in direct contact with the wafer 607 may be used (not shown) for more accurate potential measurement.

[0100] A DC power supply 635 can be used to control the flow of current to the wafer 607. The power supply 635 has a negative output lead 639 electrically connected to the wafer 607 through one or more slip rings, brushes, and contacts (not shown). The positive output lead 641 of the power supply 635 is electrically connected to the anode 613 located in the plating bath 603. The power supply 635, reference electrode 631, and contact sensing lead (not shown) can be connected to a system controller 647, which enables, among other functions, modulation of the current and potential supplied to the elements of the electroplating cell. For example, the controller may enable electroplating in a potential-controlled and current-controlled manner. The controller may include program instructions that specify not only the current and voltage that need to be applied to the various elements of the plating cell, but also the time for which these levels need to be varied. When a forward current is applied, the power supply 635 biases the wafer 607 to have a negative potential relative to the anode 613. As a result, current flows from the anode 613 to the wafer 607, causing electrochemical reduction (for example, Cu) on the wafer surface (cathode). 2+ +2e - =Cu 0 This occurs, resulting in the deposition of a conductive layer (for example, copper) on the surface of the wafer. The inert anode 614 may be placed below the wafer 607 inside the plating tank 603 and separated from the wafer area by a film 615.

[0101] The apparatus may also include a heater 645 for maintaining the temperature of the plating solution at a specific level. The plating solution may be used to transfer heat to other elements of the plating bath. For example, when a wafer 607 is loaded into the plating bath, the heater 645 and pump 617 may be turned on to circulate the plating solution through the electroplating apparatus 601 until the temperature throughout the apparatus is substantially uniform. In one embodiment, the heater is connected to a system controller 647. The system controller 647 may be connected to a thermocouple to receive feedback on the temperature of the plating solution inside the electroplating apparatus and to determine the need for additional heating.

[0102] The controller typically includes one or more storage devices and one or more processors. The processors may include a CPU or computer, analog and / or digital input / output connections, a stepper motor controller board, and the like. In certain embodiments, the controller controls all the activities of the plating apparatus. A non-temporary machine-readable medium containing instructions for controlling the processing operations according to this embodiment may be linked to the system controller.

[0103] Typically, a user interface is present associated with the controller 647. The user interface may include a display screen, a graphical software display of the apparatus and / or processing conditions, and user input devices, such as a pointing device, keyboard, touch screen, microphone, etc. Computer program code for controlling the plating process can be written in any conventional computer-readable programming language, such as assembly language, C, C++, Pascal, Fortran, etc. The processor executes the compiled object code or script to perform the tasks identified in the program. An example of a plating apparatus that may be used in the embodiments herein is the Lam Research Sabre tool. Electrodeposition can be performed within components forming a larger electrodeposition apparatus.

[0104] Figure 7 shows a schematic top view of an example of an electrodeposition apparatus. The electrodeposition apparatus 700 may include three separate electroplating modules 702, 704, and 706. The electrodeposition apparatus 700 may also include three separate modules 712, 714, and 716 configured for various processing operations. For example, in some embodiments, one or more of modules 712, 714, and 716 may be spin rinse drying (SRD) modules. Such modules may be used to rinse and dry the substrate after printing ink onto it. In other embodiments, one or more of modules 712, 714, and 716 may be post-electrofill modules (PEMs), each configured to perform functions such as edge bezel removal, back etching, and acid cleaning of the substrate after processing by one of the electroplating modules 702, 704, and 706. In some embodiments, one or more of modules 712, 714, and 716 may be configured to provide a seed layer on a substrate. In these embodiments and other embodiments, one or more of modules 712, 714, and 716 may be a pre-treatment module configured to pre-treat the substrate as described herein by removing the oxide layer from the top surface of the seed layer using, for example, a dry or wet treatment method. In these embodiments or other embodiments, one or more of modules 712, 714, and 716 may be an electrohydrodynamic extrusion printing module configured to perform the electrohydrodynamic extrusion printing process as described herein. Such an electrohydrodynamic extrusion printing module may have any one or more of the features described in relation to Figure 5. In these embodiments or other embodiments, one or more of modules 712, 714, and 716 may be a chemical etching module configured to chemically etch the substrate after electroplating as described herein. In certain embodiments, additional modules (not shown) may be provided to perform any of these or other functions described herein.

[0105] The electrodeposition apparatus 700 includes a central electrodeposition chamber 724. The central electrodeposition chamber 724 is a chamber that holds chemical solutions to be used as electroplating solutions in the electroplating modules 702, 704, and 706. The electrodeposition apparatus 700 also includes a dosing system 726 which may store and deliver additives for the electroplating solutions. A chemical dilution module 722 may store and mix chemicals to be used as etching solutions. A filtration and pumping unit 728 filters the electroplating solutions for the central electrodeposition chamber 724 and pumps them to the electroplating modules.

[0106] The system controller 730 provides electronic and interface control for operating the electroplating apparatus 700. The system controller 730 (which may include one or more physical and logical controllers) controls some or all of the characteristics of the electroplating apparatus 700.

[0107] Signals for monitoring the process may be provided from various processing tool sensors via analog and / or digital input connections to the system controller 730. Signals for controlling the process may be output on the analog and digital output connections of the processing tool. Examples of processing tool sensors that may be monitored, though not limited to these, include mass flow controllers, pressure sensors (such as pressure gauges), thermocouples, and optical position sensors. Processing conditions may be maintained using appropriately programmed feedback and control algorithms in conjunction with the data obtained from these sensors.

[0108] The hand-off tool 740 may select a substrate from a substrate cassette such as cassette 742 or cassette 744. Cassette 742 or 744 may be a FOUP. A FOUP is a sealed box designed to securely and reliably hold a substrate in a controlled environment so that it can be removed for processing or measurement by a tool equipped with a suitable load port and robotic handling system. The hand-off tool 740 may hold the substrate using a vacuum mount or some other mounting mechanism.

[0109] The hand-off tool 740 may operate in connection with a wafer handling station 732, a cassette 742 or 744, a transfer station 750, or an exposure apparatus 748. From the transfer station 750, the hand-off tool 746 may have access to the substrate. The transfer station 750 may be located in a slot or position that allows the hand-off tools 740 and 746 to pass the substrate without passing through the exposure apparatus 748. However, in some embodiments, the hand-off tool 746 may be aligned with the exposure apparatus 748 to ensure proper alignment of the substrate on the hand-off tool 746 for accurate delivery to the electroplating module. The hand-off tool 746 may also deliver the substrate to one of the electroplating modules 702, 704, or 706, or to one of three separate modules 712, 714, and 716 configured for various processing operations.

[0110] An example of a processing operation using the method described above proceeds as follows: (1) copper or other material is electrodeposited onto the substrate in the electroplating module 704, (2) the substrate is rinsed and dried in the SRD in module 712, and (3) edge bezel removal is performed in module 714.

[0111] Apparatus configured to effectively circulate the substrate through sequential plating, rinsing, drying, and PEM processing operations may be useful for implementation for use in a manufacturing environment. To achieve this, module 712 can be configured as a spin-rinsing and drying apparatus and an edge bezel removal chamber. When using such module 712, only the transfer of the substrate between the electroplating module 704 and module 712 for copper plating and EBR operations is required. In some embodiments, the method described herein is implemented within a system comprising an electroplating apparatus and a stepper.

[0112] Figure 8 schematically illustrates an alternative embodiment of the electrodeposition apparatus 800. In this embodiment, the electrodeposition apparatus 800 has a set of electroplating cells 807, each containing an electroplating bath in a pair or a number of "duet" configurations. In addition to electroplating itself, the electrodeposition apparatus 800 may perform a variety of other electroplating-related processes and substeps, such as spin-rinsing, spin-drying, wet etching of metals and silicon, electroless deposition, pre-wetting and pre-chemical treatment, reduction, annealing, electrolytic etching and / or electropolishing, photoresist stripping, and surface pre-activation. In some embodiments, the electrodeposition apparatus 800 may include one or more modules for achieving various operations described herein, such as seed layer deposition, electrohydrodynamic extrusion printing, and chemical etching. Figure 8 schematically shows the electrodeposition apparatus 800 viewed from below, and although the figure reveals only a single level or “floor,” it should be readily apparent to those skilled in the art that such apparatus, for example, the Lam Sabre® 3D tool, may have two or more “stacked” levels on top of each other, each potentially having the same or different types of processing stations.

[0113] Referring again to Figure 8, the substrates 806 to be electroplated are generally supplied to the electrodeposition apparatus 800 through a front-end loading FOUP 801, which in this example is brought from the FOUP to the main substrate processing area of ​​the electrodeposition apparatus 800 via a front-end robot 802 that can move the substrates 806, driven in multiple dimensions by a spindle 803, from one station to another available station, and in this example shows two front-end accessible stations 804 and two more front-end accessible stations 808. The front-end accessible stations 804 and 808 may include, for example, a pre-treatment station and a spin rinse drying (SRD) station. Lateral movement of the front-end robot 802 from side to side is achieved using a robot track 802a. Each of the substrates 806 may be held by a cup / cone assembly (not shown) driven by a spindle 803 connected to a motor (not shown), which may be attached to a mounting bracket 809. Furthermore, this example shows four "duets" of electroplating cells 807, with respect to a total of eight electroplating cells 807. A system controller (not shown) may be connected to the electrodeposition apparatus 800 to control some or all of the properties of the electrodeposition apparatus 800. The system controller may be programmed, or otherwise configured, to execute instructions in accordance with the processes already described herein.

[0114] Substrate processing systems, such as the substrate processing system shown in Figures 7 and 8, may be modified to include any one or more of the features described in relation to the electrohydrodynamic extrusion printing apparatus of Figure 5.

[0115] In some implementations, the controller is part of a system that may be part of the examples described above. Such a system may comprise a semiconductor processing facility including one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (such as wafer pedals and gas flow systems). In certain examples, the system may include various devices, or any subset thereof, described in relation to Figure 2B. Two or more devices may be combined into a single device, or they may all be separate from each other. Specific examples are provided above. These systems may be integrated with electronics to control their operation before, during, and after processing semiconductor wafers or semiconductor substrates. The electronics may be called “controllers” that control various components or subdivisions of one or more systems. Depending on the processing requirements and / or the type of system, the controller may be programmed to control any of the processes disclosed herein, including processing gas delivery, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, output setting, radio frequency (RF) generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid delivery setting, position and movement setting, wafer transfer into and out of tools and other transfer tools, and / or load locks connected to or interfaced with specific systems.

[0116] Broadly speaking, a controller may be defined as an electronic circuit having various integrated circuits, logic circuits, memory, and / or software that receives and issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, etc. The integrated circuit may include a chip in the form of firmware that stores program instructions, a chip defined as a digital signal processor (DSP), an application-specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions that are communicated to the controller in the form of various individual settings (or program files) that define operating parameters for performing specific operations on or for a semiconductor wafer or for a system. In some embodiments, the operating parameters may be part of a recipe defined by a processing engineer to achieve one or more processing steps while fabricating one or more layers, materials, metals, oxides, silicon, silicon oxide, surfaces, circuits, and / or wafer dies.

[0117] In some implementations, the controller may be part of, or coupled to, a computer that is integrated with, connected to, otherwise networked to, or a combination thereof, the system. For example, the controller may be in a “cloud” or all or part of a host computer system in a semiconductor factory, thereby enabling remote access to wafer processing. The computer may monitor the current progress of a fabrication operation, examine the history of past fabrication operations, enable remote access to the system to examine trends or performance metrics from multiple fabrication operations, modify parameters of the current process, set processing steps following the current process, or initiate a new process. In some examples, a remote computer (e.g., a server) may provide processing recipes to the system over a network which may include a local network or the internet. The remote computer may include a user interface that enables input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in the form of data, specifying parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of processing to be performed and the type of tool the controller is configured to interface with or control. As a result, as described above, the controller may be distributed, for example, by having one or more separate controllers networked together and working toward a common purpose, such as the processing and control described herein. One example of a distributed controller for such a purpose is one or more integrated circuits on a chamber that are in communication with one or more remotely located integrated circuits (at the platform level or as part of a remote computer, for example) to combine to control the processing on the chamber.

[0118] Without limitation, the exemplary systems may include plasma etching chambers or modules, deposition chambers or modules, spin-rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing systems that may be associated with or used in the fabrication and / or manufacture of semiconductor wafers.

[0119] As noted above, depending on one or more processing steps that the tool is to perform, the controller may communicate with one or more of the following: other tool circuits or modules, other tool components, cluster tools, other tool interfaces, nearby tools, adjacent tools, tools located throughout the factory, a main computer, another controller, or tools used for material transport that carry wafer containers between the location of tools and / or load ports within the semiconductor manufacturing plant.

[0120] conclusion The technique described herein enables the formation of fine wire interconnects, pads, and other metallic features on a very small scale with high accuracy and precision (e.g., <0.5 μm). Advantageously, the technique can be implemented without many of the conventional processes, equipment, and materials used in conventional processing flows described in relation to Figures 1A and 1B. For example, the technique herein does not require the use of photoresists, lithography tools, photoresist baking equipment, photoresist curing equipment, photomasks, developing chemicals and tooling, oxygen plasma scum removal equipment, or photoresist cleaning and stripping equipment. Therefore, ownership and processing costs associated with the formation of fine wire interconnects, pads, and other metallic features are substantially reduced. Electrohydrodynamic extrusion printing enables fine wire wiring to meet current and future market technological demands. In practice, packaging RDL wiring currently involves the formation of wires and spaces >5 μm, but is moving towards >2 μm in the coming years. The technique described herein provides a pathway for forming such features inexpensively compared to conventional processing flows that are far more costly and complex.

[0121] While the embodiments described above have been described in some detail to clarify their meaning, it will be clear that certain changes and modifications may be made within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of these embodiments. Therefore, these embodiments should be considered illustrative and not restrictive, and the embodiments should not be limited to the details shown herein. This disclosure includes the following examples of applications. [Application Example 1] A method for depositing metal onto a substrate, (a) The step of receiving the substrate having a conductive seed layer exposed on the surface of the substrate, (b) A step of printing ink onto a seed layer in a pattern by electrohydrodynamic extrusion printing, wherein the ink comprises an electroplating additive dissolved in a solvent, the electroplating additive comprises an accelerator or inhibitor, and the electroplating additive is adsorbed onto the seed layer, (c) A step of electroplating a metal onto the substrate by preferential deposition, providing a first deposition rate in the presence of the electroplating additive obtained from the ink and a second deposition rate in the absence of the electroplating additive obtained from the ink, wherein the first deposition rate is different from the second deposition rate. A method for providing this. [Application Example 2] A method according to Application Example 1, wherein the electroplating additive comprises an accelerator, and the first deposition rate is faster than the second deposition rate such that the metal is preferentially deposited in the presence of the accelerator obtained from the ink. [Application Example 3] A method according to Application Example 2, wherein the accelerator comprises an alkane chain having at least one mercapto group or at least one sulfonic acid group or an acidic salt. [Application Example 4] A method according to Application Example 3, wherein the accelerator comprises mercaptopropanesulfonic acid or mercaptoethanesulfonic acid. [Application Example 5] A method according to Application Example 3, wherein the solvent in the ink comprises at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol. [Application Example 6] A method according to Application Example 2, further comprising the step of chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming spatially isolated metallic features in the locations where the accelerator obtained from the ink is present. [Application Example 7] The method according to Application Example 6, wherein the substrate is Plating inhibitor additives in concentrations between approximately 10 ppm and 1000 ppm. Copper ions between approximately 10g / L and 60g / L Acids between approximately 5 g / L and 180 g / L, Halide ions between approximately 30 ppm and 80 ppm A method comprising electroplating in an electrolyte comprising the above (c). [Application Example 8] A method according to Application Example 7, wherein the electrolyte has no accelerator or contains only a small amount of accelerator. [Application Example 9] A method according to Application Example 1, wherein the electroplating additive comprises an inhibitor, and the first deposition rate is slower than the second deposition rate such that the metal is preferentially deposited in areas where the inhibitor obtained from the ink is absent. [Application Example 10] A method according to Application Example 9, wherein the inhibitor comprises at least one material selected from the group consisting of 6-mercaptohexanol and benzotriazole. [Application Example 11] A method according to Application Example 9, further comprising the step of chemically etching the substrate to remove a portion of the metal deposited in (c), the ink printed in (b), and a portion of the seed layer, thereby forming spatially isolated metallic features in areas where the inhibitor obtained from the ink was not present. [Application Example 12] The method according to Application Example 9, wherein the substrate is Accelerators in the range of approximately 0 ppm to 1000 ppm, Copper ions between approximately 10 g / L and 60 g / L, Acids between approximately 5 g / L and 180 g / L A method comprising electroplating in an electrolyte comprising the above (c). [Application Example 13] A method according to Application Example 12, wherein the electrolyte has neither the inhibitor nor any trace amount of the inhibitor. [Application Example 14] A method according to any one of Application Examples 1 to 13, wherein the substrate further comprises an adhesive barrier layer positioned directly below the seed layer, and the method is (d) Chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming spatially isolated metallic features, (e) electroplating the substrate with a second metal which is selectively deposited on the metallic features formed in (d) without substantially forming on the adhesive barrier layer; A way to prepare further. [Application Example 15] The method according to Application Example 14, wherein the second metal forms a diffusion barrier layer, and the method (f) A step of electroplating a solder material onto the diffusion barrier layer formed in (e) without substantially forming it on the adhesion barrier layer. A way to prepare further. [Application Example 16] A method according to any one of Application Examples 1 to 13, wherein the electroplating additive in the ink reacts with the seed layer on the substrate and chemically bonds to the seed layer on the substrate. [Application Example 17] A system for processing substrates, An electrohydrodynamic ejection printing apparatus, A nozzle having an aperture with a diameter between approximately 50 nm and 5000 nm. The nozzle and the ink reservoir connected by fluid, A substrate support for supporting the substrate during printing, and A power supply configured to apply an electric potential between the nozzle and the substrate support, or between the nozzle and the substrate. An electrohydrodynamic ejection printing apparatus equipped with, An electroplating apparatus, Chamber for holding electrolytes, A substrate holder for holding the substrate during electroplating, anode, and A power supply configured to apply a potential between the anode and the substrate during electroplating. An electroplating apparatus equipped with, It is a controller, An ink comprising an electroplating additive containing an accelerator or inhibitor, dissolved in a solvent, is printed onto the substrate in a certain pattern using the electrohydrodynamic ejection printing apparatus. The system is configured to print the ink onto the substrate, and then electroplat a metal onto the substrate using the electroplating apparatus, wherein the electroplating provides a first deposition rate where the electroplating additive obtained from the ink is present and a second deposition rate where the electroplating additive obtained from the ink is not present, and the first deposition rate is performed by preferential deposition, which differs from the second deposition rate. Controller and A system equipped with these features. [Application Example 18] A system according to Application Example 17, further comprising an apparatus configured to deposit a seed layer on the substrate, wherein the controller is configured to deposit the seed layer on the substrate before the ink is printed on the substrate. [Application Example 19] A system according to Application Example 18, further comprising a chemical etching apparatus configured to remove the metal from the substrate, wherein the controller is configured to remove a portion of the electroplated metal on the substrate and a portion of the seed layer on the substrate. [Application Example 20] A system according to any one of Application Examples 17 to 19, wherein the electrohydrodynamic ejection printing apparatus and the electroplating apparatus are provided together in a single tool. [Application Example 21] An electrohydrodynamic extrusion printing ink, (a) an electroplating additive present at a concentration between approximately 0.1 g / L and 10 g / L, comprising an accelerator or inhibitor, (b) A solvent, i. Vapor pressure of approximately 24 Torre or less at 25℃, and ii. Dielectric constant between approximately 40 and 90 A solvent having Equipped with, The ink has a viscosity between approximately 0.7 cP and 20 cP. The electroplating additive is an ink completely dissolved in the solvent. [Application Example 22] An ink as described in Application Example 21, wherein the oxygen concentration in the ink is approximately 1 ppm or less. [Application Example 23] An ink as described in Application Example 21, further comprising a species that can react with oxygen and consume the oxygen, wherein the species that can react with oxygen and consume the oxygen is present in a concentration sufficient to maintain the oxygen concentration in the ink at approximately 1 ppm or less. [Application Example 24] An ink according to Application Example 23, wherein the species that can react with oxygen and consume the oxygen comprises a sulfite compound. [Application Example 25] An ink according to Application Example 21, wherein the electroplating additive comprises the accelerator. [Application Example 26] An ink according to Application Example 21, wherein the electroplating additive comprises the inhibitor. [Application Example 27] An ink as described in Application Example 26, further comprising halide ions at a concentration between approximately 30 ppm and 80 ppm. [Application Example 28] An ink according to any one of Application Examples 21 to 27, wherein the solvent comprises at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol. [Application Example 29] An ink as described in Application Example 28, wherein the solvent is an organic substance. [Application Example 30] An ink according to any one of Application Examples 21 to 27, wherein the solvent has a natural boiling point between about 95°C and 275°C. [Application Example 31] An ink according to any one of Application Examples 21 to 27, wherein the solvent comprises a first co-solvent and a second co-solvent. [Application Example 32] An ink according to any one of the application examples 21 to 27, comprising a wetting agent. [Application Example 33] An ink according to any one of the application examples 21 to 27, comprising a salt.

Claims

1. A method for depositing metal onto a substrate, (a) The step of receiving the substrate having a conductive seed layer exposed on the surface of the substrate, (b) A step of printing ink onto the seed layer in a pattern by electrohydrodynamic extrusion printing, wherein the ink comprises an electroplating additive dissolved in a solvent, the electroplating additive comprises an accelerator, and the electroplating additive is adsorbed onto the seed layer, (c) A step of electroplating a metal onto the substrate by preferential deposition, providing a first deposition rate in the presence of the electroplating additive obtained from the ink and a second deposition rate in the absence of the electroplating additive obtained from the ink, wherein the first deposition rate is different from the second deposition rate. Equipped with, A method wherein the first deposition rate is faster than the second deposition rate such that the metal is preferentially deposited in the presence of the accelerator obtained from the ink.

2. A method according to claim 1, wherein the accelerator comprises an alkane chain having at least one mercapto group or at least one sulfonic acid group or an acidic salt.

3. A method according to claim 2, wherein the accelerator comprises mercaptopropanesulfonic acid or mercaptoethanesulfonic acid.

4. A method according to claim 2, wherein the solvent in the ink comprises at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol.

5. A method according to claim 1, further comprising the step of chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming spatially isolated metallic features in the locations where the accelerator obtained from the ink is present.

6. The method according to claim 5, wherein the substrate is Plating inhibitor additives in the range of 10 ppm to 1000 ppm, Copper ions between 10 g / L and 60 g / L Acids between 5 g / L and 180 g / L, Halide ions between 30 ppm and 80 ppm A method comprising electroplating in an electrolyte containing the above (c).

7. A method according to claim 6, wherein the electrolyte is free of an accelerator.

8. A method for depositing metal onto a substrate, (a) The step of receiving the substrate having a conductive seed layer exposed on the surface of the substrate, (b) A step of printing ink onto the seed layer in a pattern by electrohydrodynamic extrusion printing, wherein the ink comprises an electroplating additive dissolved in a solvent, the electroplating additive comprises an inhibitor, and the electroplating additive is adsorbed onto the seed layer, (c) A step of electroplating a metal onto the substrate by preferential deposition, providing a first deposition rate in the presence of the electroplating additive obtained from the ink and a second deposition rate in the absence of the electroplating additive obtained from the ink, wherein the first deposition rate is different from the second deposition rate. Equipped with, The first deposition rate is slower than the second deposition rate so that the metal is preferentially deposited in areas where the inhibitor obtained from the ink is absent. The method wherein the inhibitor comprises at least one material selected from the group consisting of 6-mercaptohexanol and benzotriazole.

9. A method according to claim 8, further comprising the step of chemically etching the substrate to remove a portion of the metal deposited in (c), the ink printed in (b), and a portion of the seed layer, thereby forming spatially isolated metallic features in areas where the inhibitor obtained from the ink was not present.

10. The method according to claim 8, wherein the substrate is Accelerators between 0 ppm and 1000 ppm, Copper ions between 10 g / L and 60 g / L, Acids between 5 g / L and 180 g / L A method comprising electroplating in an electrolyte containing the above (c).

11. A method according to claim 10, wherein the electrolyte is free of the inhibitor.

12. A method according to any one of claims 1 to 11, wherein the substrate further comprises an adhesive barrier layer positioned directly below the seed layer, and the method is (d) Chemically etching the substrate to remove a portion of the metal deposited in (c) and a portion of the seed layer, thereby forming spatially isolated metallic features, (e) electroplating the substrate with a second metal which is selectively deposited on the metallic features formed in (d) without being formed on the adhesive barrier layer. A way to prepare further.

13. The method according to claim 12, wherein the second metal forms a diffusion barrier layer, and the method (f) A step of electroplating a solder material onto the diffusion barrier layer formed in (e) without forming it on the adhesive barrier layer. A way to prepare further.

14. A method according to any one of claims 1 to 11, wherein the electroplating additive in the ink reacts with the seed layer on the substrate and chemically bonds to the seed layer on the substrate.

15. A system for processing substrates, An electrohydrodynamic ejection printing apparatus, A nozzle having an aperture with a diameter between 50 nm and 5000 nm. The nozzle and the ink reservoir connected by fluid, A substrate support for supporting the substrate during printing, and A power supply configured to apply an electric potential between the nozzle and the substrate support, or between the nozzle and the substrate. An electrohydrodynamic ejection printing apparatus equipped with, An electroplating apparatus, Chamber for holding electrolytes, A substrate holder for holding the substrate during electroplating, anode, and A power supply configured to apply a potential between the anode and the substrate during electroplating. An electroplating apparatus equipped with, It is a controller, An ink containing an electroplating additive with an accelerator, dissolved in a solvent, is printed onto the substrate in a certain pattern using the electrohydrodynamic ejection printing apparatus. The system is configured to print the ink onto the substrate, and then electroplat a metal onto the substrate using the electroplating apparatus, wherein the electroplating provides a first deposition rate where the electroplating additive obtained from the ink is present and a second deposition rate where the electroplating additive obtained from the ink is not present, and the first deposition rate is performed by preferential deposition, which differs from the second deposition rate. Controller and Equipped with, A system in which the first deposition rate is faster than the second deposition rate such that the metal is preferentially deposited in the presence of the accelerator obtained from the ink.

16. The system according to claim 15, further comprising an apparatus configured to deposit a seed layer on the substrate, wherein the controller is configured to deposit the seed layer on the substrate before the ink is printed on the substrate.

17. The system according to claim 16, further comprising a chemical etching apparatus configured to remove metal from the substrate, wherein the controller is configured to remove a portion of the electroplated metal on the substrate and a portion of the seed layer on the substrate.

18. A system according to any one of claims 15 to 17, wherein the electrohydrodynamic ejection printing apparatus and the electroplating apparatus are provided together in a single tool.

19. An electrohydrodynamic extrusion printing ink, (a) an electroplating additive present at a concentration between 0.1 g / L and 10 g / L and containing an accelerator, (b) A solvent, i. Vapor pressure of 24 Torre or less at 25°C, and ii. Dielectric constant between 40 and 90 A solvent having Equipped with, The ink has a viscosity between 0.7 cP and 20 cP. The electroplating additive is completely dissolved in the solvent. The accelerator is intended to ensure that electroplating is preferentially performed on the areas where the ink is printed on the seed layer prior to electroplating. ink.

20. An ink according to claim 19, wherein the oxygen concentration in the ink is 1 ppm or less.

21. The ink according to claim 19, further comprising a species that can react with oxygen and consume the oxygen, wherein the species that can react with oxygen and consume the oxygen is present in a concentration sufficient to maintain the oxygen concentration in the ink at 1 ppm or less.

22. The ink according to claim 21, wherein the species that can react with the oxygen and consume the oxygen comprises a sulfite compound.

23. An electrohydrodynamic extrusion printing ink, (a) an electroplating additive present at a concentration between 0.1 g / L and 10 g / L and containing an inhibitor, (b) A solvent, i. Vapor pressure of 24 Torre or less at 25°C, and ii. Dielectric constant between 40 and 90 A solvent having Equipped with, The ink has a viscosity between 0.7 cP and 20 cP. The electroplating additive is completely dissolved in the solvent. The inhibitor comprises at least one material selected from the group consisting of 6-mercaptohexanol and benzotriazole, The inhibitor is intended to ensure that, when the ink is printed on the seed layer prior to electroplating, electroplating is preferentially performed on areas where the ink is not printed. ink.

24. The ink according to claim 23, further comprising halide ions at a concentration between 30 ppm and 80 ppm.

25. An ink according to any one of claims 19 to 24, wherein the solvent comprises at least one material selected from the group consisting of water, terpineol, ethylene carbonate, propylene carbonate, dimethyl sulfoxide (DMSO), ethylene glycol, and propylene glycol.

26. An ink according to claim 25, wherein the solvent is an organic substance.

27. An ink according to any one of claims 19 to 24, wherein the solvent has a spontaneous boiling point between 95°C and 275°C.

28. An ink according to any one of claims 19 to 24, wherein the solvent comprises a first cosolvent and a second cosolvent.

29. An ink according to any one of claims 19 to 24, comprising a wetting agent.

30. An ink according to any one of claims 19 to 24, comprising a salt.

31. A system for processing a substrate, An electrohydrodynamic ejection printing apparatus, A nozzle having an aperture with a diameter between 50 nm and 5000 nm. The nozzle and the ink reservoir connected by fluid, A substrate support for supporting the substrate during printing, and A power supply configured to apply an electric potential between the nozzle and the substrate support, or between the nozzle and the substrate. An electrohydrodynamic ejection printing apparatus equipped with, An electroplating apparatus, Chamber for holding electrolytes, A substrate holder for holding the substrate during electroplating, anode, and A power supply configured to apply a potential between the anode and the substrate during electroplating. An electroplating apparatus equipped with, It is a controller, An ink containing an electroplating additive with an inhibitor, dissolved in a solvent, is printed onto the substrate in a certain pattern using the electrohydrodynamic ejection printing apparatus. The system is configured to print the ink onto the substrate, and then electroplat a metal onto the substrate using the electroplating apparatus, wherein the electroplating provides a first deposition rate where the electroplating additive obtained from the ink is present and a second deposition rate where the electroplating additive obtained from the ink is not present, and the first deposition rate is performed by preferential deposition, which differs from the second deposition rate. Controller and Equipped with, A system in which the first deposition rate is slower than the second deposition rate so that the metal is preferentially deposited in areas where the inhibitor obtained from the ink is absent.

32. The system according to claim 31, further comprising an apparatus configured to deposit a seed layer on the substrate, wherein the controller is configured to deposit the seed layer on the substrate before the ink is printed on the substrate.

33. The system according to claim 32, further comprising a chemical etching apparatus configured to remove metal from the substrate, wherein the controller is configured to remove a portion of the electroplated metal on the substrate and a portion of the seed layer on the substrate.

34. A system according to any one of claims 31 to 33, wherein the electrohydrodynamic ejection printing apparatus and the electroplating apparatus are provided together in a single tool.

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