US20040200725A1

US20040200725A1 - Application of antifoaming agent to reduce defects in a semiconductor electrochemical plating process

Info

Publication number: US20040200725A1
Application number: US10/410,105
Authority: US
Inventors: Joseph Yahalom; Mei Wen; Roman Mostovoy
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2003-04-09
Filing date: 2003-04-09
Publication date: 2004-10-14

Abstract

Embodiments of the invention provide a method and formulations for preventing foam formation inside a plating apparatus prior to or during plating a material on a substrate. In one embodiment, a method for preventing foam formation inside a plating apparatus designed for plating a material on a substrate includes providing an electrolyte solution containing at least one antifoaming agent, at least one metal ion source, and a supporting electrolyte. The method further includes placing the substrate onto a substrate holder of the plating apparatus, immersing the substrate in the electrolyte solution, and depositing the material onto the substrate.

Description

BACKGROUND OF THE INVENTION Field of the Invention

Metallization of sub-quarter micron sized features is a foundational technology for present and future generations of integrated circuit manufacturing processes. More particularly, in devices such as ultra large scale integration-type devices, i.e., devices having integrated circuits with more than a million logic gates, the multilevel interconnects that lie at the heart of these devices are generally formed by filling high aspect ratio, i.e., greater than about 4:1, interconnect features with a conductive material, such as copper. Conventionally, deposition techniques such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) have been used to fill these interconnect features. However, as the interconnect sizes decrease and aspect ratios increase, void-free interconnect feature fill via conventional metallization techniques becomes increasingly difficult. Therefore, plating techniques, i.e., electrochemical plating (ECP) and electroless plating, have emerged as promising processes for void free filling of sub-quarter micron sized high aspect ratio interconnect features in integrated circuit manufacturing processes.

In an ECP process, for example, sub-quarter micron sized high aspect ratio features formed into the surface of a substrate (or a layer deposited thereon) may be efficiently filled with a conductive material, such as copper. ECP plating processes are generally two stage processes, wherein a seed layer is first formed over the surface features of the substrate (generally through PVD, CVD, atomic layer deposition (ALD), or other deposition process in a separate tool), and then the surface features of the substrate are exposed to an electrolyte solution (in the ECP tool), while an electrical bias is applied between the seed layer and a copper anode positioned within the electrolyte solution. The electrolyte solution is generally rich in copper ions (Cu ²⁺) that are to be plated onto the surface of the substrate, and therefore, the application of the electrical bias, i.e., configuring the substrate as the cathode, causes these ions to be plated onto the seed layer, thus depositing a layer of the ions on the substrate surface that may fill the features.

Conventional electrochemical and electroless plating cells utilize various types of substrate immersion processes. However, immersion processes are prone to generate bubbles on the substrate surface, which have been shown to cause plating defects, and therefore, minimization of bubble formation is desirable. Further, plating processes generally include rotation or agitation of the substrate in the electrolyte solution, which has been shown to generate a foam at the electrolyte surface. This foam is also known to cause plating defects, and as such, should be minimized.

Therefore, a need exists to provide methods and compositions for plating processes that are designed to prevent and/or reduce bubble and/or foam formation.

SUMMARY OF THE INVENTION

Embodiments of the invention generally provide a method and formulations for preventing foam formation inside a plating apparatus prior to or during plating a material on a substrate. In one embodiment, a method for preventing foam formation inside a plating apparatus designed for plating a material on a substrate includes providing an electrolyte solution containing antifoaming agent, at least one metal ion source, and a supporting electrolyte. The method further includes placing the substrate onto a substrate holder of the plating apparatus, immersing the substrate in the electrolyte solution, and depositing the material onto the substrate.

Embodiments of the invention may further provide a method for preventing foam formation inside a plating apparatus, wherein the method includes providing an electroless plating solution containing antifoaming agent, immersing the substrate in the electroless plating solution, and depositing a material layer onto the substrate by electroless deposition in the electroless plating solution. In one aspect of the invention, the material layer includes a catalytic seed layer. In another aspect of the invention, the method further includes depositing a conductive layer on the substrate over the catalytic seed layer. In another aspect of the invention, the material layer includes a conductive layer.

Embodiments of the invention may further provide a method for preventing foam formation inside an electroless plating apparatus designed for electroless plating on a substrate includes providing a catalytic layer solution containing antifoaming agent and immersing the substrate in the catalytic layer solution. The method further includes depositing a catalytic seed layer onto the substrate by electroless deposition in the catalytic layer solution and depositing a conductive layer on the substrate over the catalytic seed layer.

Embodiments of the invention may further provide a method for preventing foam formation inside a plating apparatus designed for plating on a substrate having a metal seed layer formed thereon includes providing an electrolyte solution containing antifoaming agent. The method further includes immersing the substrate in the electrolyte solution, and depositing a conductive layer onto the metal seed layer of the substrate.

Embodiments of the invention may further provide a composition for a plating bath that is configured to reduce foam formation. The composition may include antifoaming agent selected from the group consisting of alcohols, monohydric alcohols, polyhydric alcohols, and C ₆to C₂₀alcohols, such as octal and lauryl alcohols, and combinations and derivatives thereof, at least one metal ion source, and a supporting electrolyte. Embodiments of the invention further contemplate omitting the antifoaming agent from the composition and applying the antifoaming agent to the substrate prior to plating. In this embodiment, the substrate surface having the pre-wetting antifoaming agent thereon reduces foam when it contacts the bath, and further, may slightly accumulate in the bath after several substrates have been processed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features of the invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof, which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0010]
FIGS. [0011] 1 is a flow diagram illustrating an exemplary plating process.
FIG. 2 is a perspective view of an electroplating system platform useful to perform electrochemical plating described herein. [0012]
FIG. 3 is a graphical representation of comparison analyses using the electrolyte composition of the invention.[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The words and phrases used herein should be given their ordinary and customary meaning by one skilled in the art, unless otherwise further defined herein. [0014]
Embodiments of the invention include plating methods and electrolyte compositions configured to reduce, prevent, and/or eliminate bubbles and/or foam formed in a plating apparatus or on a substrate. Methods of the invention can include both the chemical compositions configured to reduce or eliminate bubbles and/or foam, as well as a method for analyzing electrolyte solutions to determine if foam has formed or is present on the surface of the solution. The monitoring process may include in situ analysis of the plating solution, or alternatively, a sampling of the bath may be cut therefrom and analyzed separately for the presence of foam. [0015]
Embodiments of the invention also provide a composition for presenting and/or removing excess bubbles or foams at the surface of the substrate without damaging the devices formed on the substrate surface. A typical composition that can be employed to prevent or reduce the excess bubbles or foam can include antifoaming agent, such composition can be used in a plating process together with an electrolyte solution containing at least one metal ion source, a supporting electrolyte, and water. [0016]
FIG. 1 is a flow chart illustrating an [0017] exemplary method 100 of the invention to prevent and monitor bubble or foam formation in a plating bath. The method 100 of FIG. 1 includes preparing an electrolyte solution at step 110, wherein the solution generally includes an antifoaming agent, a supporting electrolyte, a metal ion source, and water. The metal ion source may be metal salts generally required for plating a desired material onto a substrate. The metal salts may include any of the suitable metal salts for the material to be plated on the substrate, such as copper salts, noble metal salts, semi-noble metal salts, Group IV metal salts, etc. Typical materials to be plated that can be used herein include, but are not limited to, copper, nickel, gold, silver, and tungsten. The starting electrolyte solution is thus generally prepared and pre-mixed before supplying to a plating apparatus.
The antifoaming agent that can be used herein includes, but is not limited to, the family of alcohols, such as propanol, butanol, pentanol, hexanol, heptanol, octanol (octyl alcohol), monohydric alcohols, polyhydric alcohols, C6 to C20 alcohols, lauryl alcohol, and any mixtures and derivatives thereof. Other suitable antifoaming agents that can be used herein include, but are not limited to, hydrophobic oils, amines, alkyl amines, diamyl methyl amine, amides, acyl derivatives of piperazine, alkaline earth, sodium stearate, aluminum stearate, hydrophobic compounds, hydrophobic silica, and combinations and derivatives thereof. However, generally speaking, the inventors acknowledge that not all of the above noted compounds and solutions are amenable to plating solutions. Currently, the C6 to C20 alcohols are the preferred antifoaming agents, however, as technology advances, the inventors acknowledge, and in fact contemplate that the alternative compounds and solutions that are currently undesirable in a plating solutions may in fact become practical and preferred. [0018]
In one embodiment, the antifoaming agent may be prepared as a stock solution before being added into the electrolyte solution. For example, the antifoaming agent can be dissolved in a solvent at a concentration of between about 1% and about 50%. The solvent can be selected from a variety of compounds that, when prepared in a solution, help to dissolve the antifoaming agent. The compounds suitable as the solvent for antifoaming agent include, but are not limited to, alcohols (e.g., ethanol, methanol, etc.), siloxanes, polydimethyl siloxane, and combinations and derivatives thereof. [0019]
The antifoaming agent can be added into the electrolyte solution to a final concentration of between about 0.002% and about 10% by volume, such as between about 0.01% and about 5% by volume, depending on the antifoaming agent and supporting electrolyte used. One working example of the antifoaming agent that can be used is at a final concentration of about 0.01% of 1-octanol in the electrolyte solution because of its effectiveness and physical stability. Another example is a stock solution of between about 5% and about 30% of 1-octanol dissolved in ethanol that can be added to an electrolyte solution to a final concentration of between about 0.005% and about 0.25% of 1-octanol in the electrolyte solution, such as about 0.01% or about 0.05% of 1-octanol in the electrolyte solution. In general, it is more economical to dissolve the antifoaming agent into solutions of higher concentration (e.g., a stock solution) to be more effective before diluting into a final electrolyte solution. [0020]
On the other hand, electroless plating may employ multiple electrolyte solutions and complex components in an electrolyte. Typical electrolyte components for electroless deposition include, but are not limited to, noble metal salts, semi-noble metal salts, other suitable metal salts, complexing agents, additives, surfactants, stabilizers, and pH adjusting agents. Examples of noble metals include gold, silver, platinum, palladium, iridium, rhenium, ruthenium, and osmium. Examples of semi-noble metals include, iron, cobalt, nickel, copper, and tungsten. [0021]
Various supporting electrolytes for electroplating and electroless plating, as well as plating apparatuses can be purchased from Applied Materials, Inc. of Santa Clara, Shipley Inc. of Marlborough, Mass., CPI International (CPI) of Santa Rosa, Calif., or Enthone OMI of New Haven, Conn. In one embodiment it is preferred that the antifoaming agent used does not interact with the supporting electrolyte components. [0022]
Returning to the method illustrated in FIG. 1, at step [0023] 120 a substrate is placed onto a substrate holder of a plating apparatus configured to use the prepared electrolyte discussed above. Step 120 also includes connecting electrical power to a plurality of electrical contacts positioned in communication with the substrate and immersing the substrate in the electrolyte solution. A negative voltage is then applied to the substrate or the seed layer deposited thereon during the immersion to prevent etching on the surface of the substrate (e.g., the side walls of vias and trenches) by of the plating electrolyte solution. In general, the antifoaming agent in the electrolyte solution is designed to prevent bubble and foam formation on the surface of the electrolyte solution, which is known to adhere to the plating surface and cause defects. The electrolyte solution containing the antifoaming agent results in reduced propensity of the electrolyte solution to create and/or sustain bubbles that can be trapped against the surface of the substrate. The reduction in the number and size of bubbles reduces the number of defects typically found on the substrate after plating.
At [0024] step 130, a material is deposited on the substrate by an electrochemical deposition process, for example, by use of an electrolyte solution. Agitating the electrolyte solution inside the plating apparatus is generally employed and one of the advantages of the antifoaming agent to be included herein in the electrolyte solution is to prevent bubble or foam formation during such agitation process, by, for example, rotating the wafer.
At [0025] step 140, an optional step is performed to monitor bubble or foam formation inside the plating apparatus. For example, precision monitoring equipment may be used to determine the presence and/or thickness of a foam layer on the surface of a plating bath, as the foam thickness generally has a thickness on the order of a monolayer. The measurement may be made in situ, or alternatively, a sample of the solution may be taken from near the surface of the bath and then analyzed in a separate analyzer. The determination that foam is present can be used to dispense additional antifoaming agents into the bath, or possibly to determine when the useful life of the bath has been reached when form forms with the antifoaming agent already contained in the bath. Regardless, at step 150 the substrate may be removed from the cell.
Electroless plating involves an auto-catalyzed chemical deposition process that requires a surface capable of electron transfer for subsequent deposition and nucleation of a conductive material, such as a catalytic layer containing noble metals, semi-noble metals, and alloys thereof. Noble metals and semi-noble metals are not readily oxidized, and thus provide a surface capable of electron transfer. However, trapped gas and other bubbles, such as hydrogen gas, are formed in the catalytic layer during an electroless deposition process. [0026]
Therefore, in one embodiment of the invention, a method is provided for preventing foam formation during electroless deposition of a catalytic layer. The method generally includes the insertion of the substrate into an electroless plating apparatus, dispensing a catalytic layer solution, removing the catalytic layer solution, then rinsing with water or other rinsing solutions. For example, the method may include contacting the substrate with an aqueous catalytic layer solution containing Group IV metal ions, such as tin ions, and then contacting the substrate with another aqueous catalytic layer solution containing noble metal ions, semi-noble metal ions, or combinations thereof. The catalytic layer solution may generally include antifoaming agent as described herein to prevent foam formation and remove entrapped gas, such as hydrogen gas, formed during electroless deposition. Thus, a catalytic seed layer is deposited onto the substrate by electroless deposition in the catalytic layer solution. [0027]
In another embodiment of the invention, a method is provided for preventing foam formation during electroless deposition of a conductive layer. The method generally includes the insertion of the substrate into an electroless plating apparatus, dispensing an electroless plating solution, then removing the electroless solution, then rinsing the substrate with water or other rinsing solutions, and removing the substrate from the electroless plating apparatus. In general, an electroless electrolyte solution containing antifoaming agent and other various chemical constituents required for electroless deposition is prepared before placing the substrate onto the substrate holder of the electroless plating apparatus and having the electroless electrolyte solution supplied on the surface of the substrate. Such electroless plating solution for a conductive layer may include, but is not limited to, metal salts for the material of the conductive layer, other suitable salts, complexing agents, additives, stabilizers, reducing agents, and pH adjusters. For example, an exemplary electroless plating solution includes copper sulfate, ethylenediaminetetraacetic acid (EDTA) as a complexing agent, formaldehyde (HCHO) as the reducing agent, and sodium hydroxide to adjust the pH of the electroless plating solution. A discussion of an exemplary electroless deposition process is described in the co-pending U.S. patent application Ser. No. 10/059,822, entitled “Electroless Deposition Method Over Sub-Micron Apertures”, filed on Jan. 28, 2002, which is incorporated by reference herein. [0028]
A chemical reaction among the principal components of an electroless deposition process for a conductive layer typically generates gases, such as hydrogen gas. It is believed that the use of antifoaming agent as described herein helps to remove trapped hydrogen gas formed in the conductive layer during the deposition process and thus prevents defect formation on the substrate. [0029]
Plating System: [0030]
Embodiments of the invention provide a plating method and compositions that can be performed in various plating systems. One example of an electrochemical plating system that may be used herein is an Electra integrated Electro-Chemical Plating (iECP) System available from Applied Materials, Inc., of Santa Clara, Calif. Another example is an ELECTRA CU™ ECP platform, available from Applied Materials, Inc. of Santa Clara, Calif. The electroplating apparatus is more fully described in U.S. patent application Ser. No. 09/289,074, entitled “Electro-Chemical Deposition System” filed Apr. 8, 1999, which is incorporated by reference herein. In addition, any system enabling electrochemical processing using the analytical methods or techniques described herein may also be used. Another example of a suitable plating apparatus is disclosed in U.S. patent application Ser. No. 10/268,284, entitled, “Electrochemical Processing Cell”, filed on Oct. 9, 2002, which is incorporated by reference herein. A discussion of an exemplary electroless deposition system is described in the co-pending U.S. patent application Ser. No. 10/059,572, entitled “Electroless Deposition Apparatus”, filed on Jan. 24, 2002, is also incorporated by reference herein. [0031]
FIG. 2 is a perspective view of an [0032] electroplating system platform 200 of the invention. The electroplating system platform 200 generally includes a mainframe 214 having a mainframe substrate transfer robot, a loading station 210 disposed in connection with the mainframe 214, one or more processing cells 240 disposed in connection with the mainframe, a spin-rinse-dry (SRD) station 212, and an electrolyte replenishing system 220 fluidly connected to the one or more electrical processing cells 240. Additionally, the electroplating system platform 200 is enclosed in a clean environment using panels, such as plexiglass panels.
The [0033] mainframe 214 generally includes a mainframe transfer station 216 and a plurality of processing stations 218. Each processing station 218 includes one or more processing cells 240. An electrolyte replenishing system 220 is positioned adjacent the electroplating system platform 200 and connected to the process cells 240 individually to circulate electrolyte used for the electroplating process. The electroplating system platform 200 also includes a control system 222, typically a programmable microprocessor. The control system 222 also provides electrical power to the components of the system and includes a control panel 223 that allows an operator to monitor and operate the electroplating system platform 200.
The [0034] loading station 210 typically includes one or more substrate cassette receiving areas 224, one or more loading station transfer robots 228 and at least one substrate orientor 230. The number of substrate cassette receiving areas, loading station transfer robots 228, and substrate orientor 230 included in the loading station 210 can be configured according to the desired throughput of the system. A substrate cassette containing substrates is loaded onto the substrate cassette receiving area 224 to introduce substrates into the electroplating system platform. The substrate orientor 230 positions each substrate in a desired orientation to ensure that each substrate is properly processed. The loading station transfer robot 228 transfers substrates between the substrate cassette and the substrate orientor 230. The loading station transfer robot 228 also transfers substrates between the loading station 210 and the SRD station 212.
The [0035] electroplating process cell 240 generally includes a head assembly, a process kit and an electrolyte collector. The head assembly includes a substrate holder assembly having a substrate holder 264 and a cathode contact ring. The head assembly is provided to position the substrate in a processing position and in a substrate loading position. In one embodiment, the head assembly is a rotatable head assembly having a rotational actuator disposed and attached to the head assembly to rotate the head assembly during substrate processing.
In another embodiment, the [0036] electrolyte replenishing system 220 includes one or more degasser modules adapted to remove undesirable gases from the electrolyte. The degasser module generally includes a membrane that separates gases from the fluid passing through the degasser module and a vacuum system for removing the released gases. The degasser modules are preferably placed in line on the electrolyte supply line adjacent to the process cells 240. The degasser modules are preferably positioned as close as possible to the process cells 240 so that most of the gases from the electrolyte replenishing system are removed by the degasser modules before the electrolyte enters the process cells. The degasser modules can be placed at many other alternative positions. A commercially available degasser module is available from Millipore Corporation, located in Bedford, Mass.

EXAMPLE

Examples of reducing, preventing, and/or eliminating foam formation using the electrolyte compositions as described above are presented herein. Typical concentrations of the electrolyte that may be used are as follows. The concentrations of the inorganic components may be, for example, between about 5 grams per liter (g/L) to about 80 g/L of copper sulfate, such as between about 10 g/L and about 60 g/L, between about 30 ppm and about 200 ppm of hydrochloric acid, and between about 5 g/L to about 200 g/L of sulfuric acid. The concentrations of the organic components in a plating bath that can be analyzed/measured by the CVS, titration, and other methods known in the semiconductor art, and may be present at concentrations of between about 0.1% to about 2.5% by volume of an accelerator, brightener, or anti-suppressor, between about 0.1% and about 6% by volume of a suppressor, carrier, surfactant, or wetting agent, and between about 0.1% to about 2% by volume of a leveler, over-plate inhibitor, or grain refiner. Various components (both hardware and chemicals) used herein were purchased from Applied materials, Inc. of Santa Clara, Shipley Inc. of Marlborough, Mass., CPI International (CPI) of Santa Rosa, Calif., or Enthone OMI of New Haven, Conn. [0037]
FIG. 3 demonstrates the effect of various concentrations of an antifoaming agent on foam formation. Foam thickness is plotted against various concentrations of 1-octanol (dissolved in ethanol first). Two different supporting electrolytes, i.e., a 2 component electrolyte and a 3 component electrolyte, with one shown as solid squares and the other shown as solid diamond in FIG. 3, are compared in the absence (zero concentration of antifoaming agent) and presence of the added antifoaming agent. Generally, the foam height drops as the antifoaming agent is added. In FIG. 3, the effective concentration of the antifoaming agent is different for the two supporting electrolytes used. Thus, best antifoaming effect can be achieved at a minimum concentration of about 0.01% of the antifoaming agent in one supporting electrolyte (solid square) and at a minimum concentration of about 0.016% of the same antifoaming agent used in another supporting electrolyte (solid diamond). [0038]
While the foregoing is directed to various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. [0039]

Claims

What is claimed is:

1. A method for preventing foam formation inside a plating cell, comprising:

providing an electrolyte solution to the cell, the electrolyte solution containing an antifoaming agent, a metal ion source, and a supporting electrolyte;

placing the substrate onto a substrate holder of the plating apparatus;

immersing the substrate in the electrolyte solution; and

depositing the material onto the substrate.

2. The method of claim 1, further comprising connecting electrical power to a plurality of electrical contacts disposed to contact the surface of the substrate after the substrate is placed onto the substrate holder.

3. The method of claim 1, further comprising monitoring foam formation inside the plating apparatus and dosing the antifoaming agent into the electrolyte solution in accordance with a measured foam thickness.

4. The method of claim 1, wherein the metal ion source is copper.

5. The method of claim 1, wherein the antifoaming agent is selected from the group consisting of alcohols, monohydric alcohols, polyhydric alcohols, octyl alcohol, C₆to C₂₀alcohols, lauryl alcohol, and combinations and derivatives thereof.

6. The method of claim 1, wherein the antifoaming agent is dissolved in ethanol.

7. The method of claim 1, wherein the antifoaming agent is 1-octanol dissolved in ethanol.

8. The method of claim 1, wherein the antifoaming agent is at a final concentration of between about 0.002% and about 10% by volume in the electrolyte solution.

9. The method of claim 1, wherein one metal ion source comprises a metal salt selected from the group consisting of copper salt, noble metal salt, semi-noble metal salt, and combinations thereof.

10. The method of claim 1, wherein the supporting electrolyte comprise acid and water.

11. A method for preventing foam formation inside an electroless plating apparatus, comprising:

providing an electroless plating solution containing at least one antifoaming agent;

immersing the substrate in the electroless plating solution; and

depositing a material layer onto the substrate by electroless deposition in the electroless plating solution.

12. The method of claim 11, wherein the material layer comprises a catalytic seed layer.

13. The method of claim 12, further comprising depositing a conductive layer on the substrate over the catalytic seed layer.

14. The method of claim 11, wherein the material layer comprises a conductive layer.

15. The method of claim 11, wherein the at least one antifoaming agent is selected from the group consisting of alcohols, monohydric alcohols, polyhydric alcohols octyl alcohol, C₆to C₂₀alcohols, lauryl alcohol, hydrophobic oils, amines, alkyl amines, diamyl methyl amine, amides, acyl derivatives of piperazine, alkaline earth, sodium stearate, aluminum stearate, hydrophobic compounds, hydrophobic silica, and combinations and derivatives thereof.

16. The method of claim 11, wherein the at least one antifoaming agent is at a final concentration of between about 0.002% and about 10% by volume in the plating electrolyte solution.

17. A method for preventing foam formation inside an electroless plating apparatus designed for electroless plating on a substrate, comprising:

providing a catalytic layer solution containing at least one antifoaming agent;

immersing the substrate in the catalytic layer solution;

depositing a catalytic seed layer onto the substrate by electroless deposition in the catalytic layer solution; and

depositing a conductive layer on the substrate over the catalytic seed layer.

18. The method of claim 17, wherein the conductive layer is deposited by a deposition technique selected from the group consisting of physical vapor deposition, chemical vapor deposition, electrochemical plating, electroless plating, and combinations thereof.

19. A method for preventing foam formation inside a plating apparatus designed for plating on a substrate having a metal seed layer formed thereon, comprising:

providing an electrolyte solution containing at least one antifoaming agent;

immersing the substrate in the electrolyte solution; and

depositing a conductive layer onto the metal seed layer of the substrate.

20. The method of claim 19, further comprising monitoring foam formation inside the plating apparatus and dosing the antifoaming agent into the electrolyte solution.

21. The method of claim 19, wherein the at least one antifoaming agent is selected from the group consisting of alcohols, monohydric alcohols, polyhydric alcohols octyl alcohol, C₆to C₂₀alcohols, lauryl alcohol, hydrophobic oils, amines, alkyl amines, diamyl methyl amine, amides, acyl derivatives of piperazine, alkaline earth, sodium stearate, aluminum stearate, hydrophobic compounds, hydrophobic silica, and combinations and derivatives thereof.

22. The method of claim 19, wherein the at least one antifoaming agent is dissolved in at least one solvent selected from the group consisting of alcohols, ethanol, siloxanes, polydimethyl siloxane, and combinations and derivatives thereof, before adding to the electrolyte solution.

23. The method of claim 19, wherein the at least one antifoaming agent is at a final concentration of between about 0.002% and about 10% by volume in the electrolyte solution.

24. A composition for a plating bath, comprising:

at least one antifoaming agent selected from the group consisting of alcohols, monohydric alcohols, polyhydric alcohols octyl alcohol, C6 to C20 alcohols, lauryl alcohol, and combinations and derivatives thereof;

a metal ion source; and

a supporting electrolyte.

25. The composition of claim 24, wherein the at least one antifoaming agent is first dissolved in at least one solvent selected from the group consisting of alcohols, ethanol, siloxanes, polydimethyl siloxane, and combinations and derivatives thereof.

26. The composition of claim 24, wherein the at least one antifoaming agent is 1-octanol dissolved in ethanol.

27. The composition of claim 24, wherein the at least one antifoaming agent is at a final concentration of between about 0.002% and about 10% by volume.

28. The composition of claim 24, wherein the at least one metal ion source comprise a metal salt selected from the group consisting of copper salt, noble metal salt, semi-noble metal salt, and combinations thereof.