Patent Application
20120292195
This application claims the benefit of Korean Patent Application No. 10-2011-0047188 filed on May 19, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field
The inventive concept relates to an apparatus and method for electroplating a semiconductor substrate, and more particularly, to an apparatus and method for electroplating a semiconductor substrate with a uniform plate film on a surface thereof.
2. Description of the Related Art
In general, electroplating apparatuses for plating a material, e.g., silver and copper, on a surface of a part to be plated, e.g., on a surface of a semiconductor wafer, use an electroplating method. The electroplating method is widely used because the property of a metal film coated by the electroplating method is superior to that of a metal film coated by, e.g., a chemical vapor deposition method or a physical vapor deposition method.
According to the electroplating principle, a part to be plated as a negative electrode and metal to be electrodeposited as a positive electrode may be dipped into an electrolyte solution containing metal ions to be electrodeposited. The two electrodes are electrically connected to each other and electrolyzed so that desired metal ions may be deposited on a surface of the part to be plated.
Embodiments are directed to an apparatus and method for electroplating a semiconductor substrate by selectively increasing the flow of an electrolyte solution at a predetermined area where a supply amount of metal ions of the electrolyte solution needs to be relatively increased, thereby increasing thickness uniformity of a deposited metal layer formed by the electroplating.
According to an aspect of the inventive concept, there is provided an apparatus for electroplating a semiconductor device which includes a plating bath accommodating a plating solution, and a paddle in the plating bath, the paddle including a plurality of holes configured to pass the plating solution through the paddle toward a substrate, and a plating solution flow reinforcement portion configured to selectively reinforce a flow of the plating solution to a predetermined area of the substrate, the predetermined area of the substrate being an area requiring a relatively increased supply of metal ions of the plating solution.
The plating solution flow reinforcement portion may be on the paddle and may face the substrate.
The plating solution flow reinforcement portion may include at least one protrusion member protruding from the paddle toward the substrate.
The plating solution flow reinforcement portion may include a plurality of protrusion members, the protrusion members being separated from each other and arranged along a circumference of the paddle at a same radius.
The at least one protrusion member may be detachable, the protrusion member being a tab coupled to a corresponding hole of the plurality of holes in the paddle.
The tab may include a male thread, the tab being coupled to the corresponding hole via a female thread on an inner surface of the hole.
The plating solution flow reinforcement portion may include an insulation material.
The plating solution flow reinforcement portion may include at least one groove recessed into a lower surface of the paddle.
The apparatus may further include an anode and a cathode in the plating bath, each of the anode and cathode being separated from the paddle, and the plating solution flow reinforcement portion being position in an electric field generated between the anode and cathode.
The apparatus may further include a linear flow guide portion on the anode, the linear flow guide portion being configured to linearly guide flow of the plating solution toward the paddle.
The linear flow guide portion may be a turbulence suppressor pad coupled to a groove on a surface of the anode, the turbulence suppressor pad having a shape corresponding to the groove.
The linear flow guide portion may be a porous media coupled to the anode.
The apparatus may further include a plating solution ejection member at an upper portion of the plating bath, the plating solution ejection member being configured to eject the plating solution from the upper portion of the plating bath toward a lower portion of the plating bath.
According to an aspect of the inventive concept, there may also be provided an apparatus for electroplating a semiconductor device which includes a plating bath accommodating a plating solution, an anode and a cathode in the plating bath, a paddle between the anode and cathode, the paddle being spaced apart from each of the anode and cathode, and the paddle including a plurality of holes configured to pass the plating solution through the paddle toward a substrate, the substrate being on the cathode, and a plating solution flow reinforcement portion in an electric field generated between the anode and cathode, the plating solution reinforcement portion being positioned above a first area of the substrate, the first area of the substrate receiving a lower amount of the plating solution than a second area of the substrate when the electric field is not generated.
The plating solution flow reinforcement portion may be in the paddle, a shape of the plating solution flow reinforcement portion being configured to increase eddy flow in the first area of the substrate.
According to an aspect of the inventive concept, there may also be provided a method of electroplating a semiconductor device, the method including determining a predetermined area of a substrate requiring a relatively increased supply of metal ions of a plating solution, providing a plating bath with a paddle, the paddle including a plurality of holes configured to pass the plating solution through the paddle toward the substrate, and a plating solution flow reinforcement portion configured to selectively reinforce a flow of the plating solution in the predetermined area of the substrate, installing the substrate in the plating bath, and forming a plating film having a substantially uniform thickness on an entire surface of the substrate by supplying the plating solution to the plating bath and forming an electric field in the plating bath.
Forming the electric field in the plating bath may include forming the plating solution flow reinforcement portion between an anode and a cathode in the plating bath.
Providing the plating bath may include forming the plating solution flow reinforcement portion to include at least one protrusion member that protrudes from the paddle toward the substrate.
Forming the plating solution flow reinforcement portion may include arranging a plurality of protrusion members along a circumference of the paddle at a same radius and separated from each other, the protrusion members including a plurality of tabs selectively coupled to the plurality of holes of the paddle to be detachable.
Providing the plating bath may include forming the plating solution flow reinforcement portion to include at least one groove at a surface of the paddle to be recessed from the surface.
Features will become apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which:
Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer (or element) is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Further, it will also be understood that when a layer is referred to as being “connected to” another layer, it can be the only layer connected to the other layer, or one or more intervening layers may also be present. Other expressions describing the relationship between the constituent elements may be construed in the same manner. Like reference numerals refer to like elements throughout.
Terms such as “first” and “second” are used herein merely to describe a variety of constituent elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one constituent element from another constituent element. For example, without departing from the right scope of the present inventive concept, a first constituent element may be referred to as a second constituent element, and vice versa.
The terms used in the present specification are used for explaining a specific exemplary embodiment, not limiting the present inventive concept. Thus, the expression of singularity in the present specification includes the expression of plurality unless clearly specified otherwise in context. Also, the terms such as “include” or “comprise” may be construed to denote a certain characteristic, number, step, operation, constituent element, or a combination thereof, but may not be construed to exclude the existence of or a possibility of addition of one or more other characteristics, numbers, steps, operations, constituent elements, or combinations thereof.
Unless defined otherwise, all terms used herein including technical or scientific terms have the same meanings as those generally understood by those skilled in the art to which the present inventive concept may pertain. The terms as those defined in generally used dictionaries are construed to have meanings matching that in the context of related technology and, unless clearly defined otherwise, are not construed to be ideally or excessively formal.
Hereinafter, the inventive concept will be described in detail by explaining embodiments of the inventive concept with reference to the attached drawings.
Referring to
The plating bath 10 may be a vessel or a container for accommodating a plating solution and for performing a plating work. A plating solution ejection member 11, e.g., a nozzle 11, for supplying a plating solution may be arranged at, e.g., a center portion of an upper side of, the plating bath 10. The plating solution ejection member 11 may be connected to a plating solution storing tank T via a plating solution supply line L. A pump P and a filter F may be sequentially provided along the plating solution supply line L. Also, the plating solution storing tank T may be connected to a plating solution return line RL.
In the present exemplary embodiment, the plating solution ejection member 11 may be arranged at the upper side of the plating bath 10 and may supply a plating solution from the upper side of the plating bath 10 to the lower side thereof, so that the plating solution forms a downward flow. However, the scope of the present inventive concept is not limited thereto. That is, by having a surface of the substrate W exposed in the downward direction, e.g., by exposing a bottom surface of the substrate, which is opposite to the arrangement according to the present exemplary embodiment, the cathode 30 may support the substrate W at the upper side and the plating solution ejection member 11 may supply the plating solution from the lower side to the upper side.
Also, in the present exemplary embodiment, the plating solution ejection member 11, i.e., the nozzle 11, penetrates through the anode 20 so that the supply or downward flow of the plating solution is not interrupted by the anode 20. Although only one plating solution ejection member 11 is provided in the present exemplary embodiment, the scope of the present inventive concept is not limited thereto and a plurality of plating solution ejection members may be provided. The plating solution supplied from the plating solution ejection member 11 may be ejected in one direction or may be sprayed in a plurality of directions. The plating solution accommodated in the plating bath 10 may include, e.g., silver ions, nickel ions, copper ions, gold ions, or a combination thereof.
The anode 20 is connected to a positive terminal of a power supply unit 50 and functions as a positive electrode. In the present exemplary embodiment, the anode 20 is arranged at the upper side of the plating bath 10. Any material that does not contaminate a plating solution during a plating work may be used as a material for the anode 20. For example, either an insoluble material or a soluble material may be used for the anode 20.
In the case of using an insoluble material, an anode reaction voltage increases, so decomposition reaction of an organic additive increases. Also, the plating solution may be contaminated by byproducts after the decomposition reaction. Thus, the reaction voltage is controlled or the insoluble material may be used with an apparatus for controlling the decomposition reaction not to affect the plating solution.
In the case of using a soluble material for the anode 20, since an anode component is dissolved in the plating solution, the plating solution may be contaminated. To prevent such a problem, the same material as a plating material included in the plating solution may be used. Also, when the anode component is dissolved in the plating solution, a surface of the anode 20 becomes uneven so that the distance from each point on the surface of the anode 20 to the substrate W that is a part to be plated may vary. Accordingly, a difference in charge density may occur at the respective positions in an adjacent area of the substrate W that is a part to be plated due to the difference in the distance. Thus, when the anode 20 formed of a soluble material is in use, the difference in charge density due to the difference in the distance may be reduced by separating the anode 20 from the cathode 30 by a predetermined distance.
The cathode 30 may be provided at the lower side of the plating bath 10 and may form an electric field in the plating bath 10 with the anode 20. The substrate W that is a part to be plated may be installed at one side of the cathode 30 facing the anode 20. The substrate W may be supported by the cathode 30.
The cathode 30 may be installed to be electrically connected to the substrate W that is a part to be plated. For example, when the cathode 30 is installed in a form of a jig connected to an external power, a peripheral portion of the substrate W that is a part to be plated is placed across the jig so that the substrate W and the cathode 30 may be electrically connected to each other. The substrate W may be, e.g., a wafer.
The paddle 40 may be provided in the plating bath 10 to be disposed between the anode 20 and the cathode 30. By controlling the flow of a plating solution, the paddle 40 may selectively adjust an amount of plating ions deposited on the surface of the substrate W, so that a plating film with a substantially uniform thickness may be deposited on an entire surface of the substrate W.
The paddle 40 may include an area for passing plating ions and an area for blocking the plating ions. For example, as illustrated in
The distance from the paddle 40 to the anode 20 or the cathode 30 may be properly adjusted in accordance with factors of the electroplating process, e.g., supply speed of a plating solution, movement speed of plating ions, composition of an additive used, etc.
The paddle 40 may be formed of an insulation material or a surface thereof may be coated with an insulation material. Examples of an insulation material may include ceramic, polytetrafluorethylene, polyvinyl chloride, polypropylene, polycarbonate, polyethylene, polystyrene, etc.
In general, among factors for determining a plating thickness, it is important how rapidly metal ions of a plating solution are supplied. For example, an amount of supplied metal ions may be relatively increased by making the flow of metal ions smooth, thereby increasing a plating thickness.
In the present exemplary embodiment, however, in order to increase thickness uniformity, a predetermined area of the substrate W, where a plating thickness is relatively thin, e.g., due to low supply of metal ions during plating, may be recognized. Further, an increased supply of metal ions, e.g., only, to the predetermined area may increase uniformity of plating thickness and composition as compared to a related art. To this end, in the present exemplary embodiment, a plating solution flow reinforcement portion 41 may be provided in the paddle 40 to achieve uniform thickness of a deposited film. That is, the plating solution flow reinforcement portion 41 may selectively reinforce the flow of a plating solution at the predetermined area of the substrate W, i.e., where the amount of supplied metal ions is low. Thus, the thickness of a plating film may be uniform compared to a related art.
As illustrated in
Also, in the present exemplary embodiment, the plating solution flow reinforcement portion 41, i.e., the protrusion members 41, may be arranged along a circumference of the paddle 40, i.e., at a same radius. The protrusion members 41 may be separated from each other and coupled to the holes 40a of the paddle 40. When the protrusion members 41 are coupled to the paddle 40 to protrude downwardly, the plating solution passing through the holes 40a of the paddle 40 generates eddy flow in the vicinity under each of the protrusion members 41. Accordingly, the supply of metal ions under each of the protrusion members 41 increases.
In detail, when the predetermined area of the substrate W, i.e., where the plating thickness is relatively thin because the amount of supply of metal ion is relatively small during the plating process, is recognized, the metal ions are rapidly supplied to the predetermined area through the plating solution flow reinforcement portion 41. That is, the protrusion members 41 are arranged and provided on the paddle 40 to protrude downwardly, i.e., from the paddle 40 toward the cathode 30, at regions corresponding to the predetermined area. As a result, a plating film M may have increased thickness in regions under the protrusion members 41, as illustrated in
The protrusion members 41 may be formed by attaching tabs 41′ into some of the holes 40a of the paddle 40. For example, the protrusion members 41 may be detachable, so the tabs 41′ may be selectively inserted into respective holes 40a to overlap the predetermined region of the substrate W. When the tabs 41′ are used as the protrusion members 41, as illustrated in
For example, the protrusion members 41 may be formed of an insulation material, e.g., the same insulation material as the paddle 40, not to prevent the flow of current in the plating bath 10. In another example, surfaces of the protrusion members 41 may be coated with an insulation material.
As such, the plating solution flow reinforcement portion 41, i.e., the protrusion members 41, installed at the paddle 40 according to example embodiments may increase the thickness of the plating film in a vertical area under the protrusion members 41 and the composition of the plating ions, i.e., silver ions. Accordingly, when the protrusion members 41 are properly installed above an area of the substrate W to be plated, the thickness or composition of the plating film may be selectively controlled. As a result, the thickness or composition of the plating film may be made substantially uniform on an entire surface of the substrate W.
A method of electroplating a semiconductor substrate using the apparatus for electroplating a semiconductor substrate according to the above-described exemplary embodiment is described below with reference to
As described above, the method of electroplating a semiconductor substrate according to the present exemplary embodiment may include determining a predetermined area of the substrate W that requires an increased supply of plating solution to form a plating film with a substantially uniform thickness on the entire surface of the substrate W (S100), providing the plating bath 10 with the paddle 40 and the plating solution flow reinforcement portion 41 for selectively reinforcing flow of the plating solution in the predetermined area (S200), installing the substrate W in the plating bath 10 (S300), and forming a plating film on the surface of the substrate W by supplying the plating solution to the plating bath 10 and forming an electric field between the anode 20 and the cathode 30 provided in the plating bath 10 (S400).
In detail, the predetermined area of the substrate W to be plated may be determined (S100). The predetermined area may be a first area of the substrate W, which conventionally receives, i.e., without use of the plating solution flow reinforcement portion 41, a lower amount of metal ions of the plating solution during plating than a second area of the substrate W.
Then, the paddle 40 having the plating solution flow reinforcement portion 41 for selectively reinforcing flow of the plating solution in the predetermined area is provided in the plating bath 10 (S200). That is, the plating solution flow reinforcement portion 41, i.e., the protrusion members 41, may be installed in holes 40a of the paddle 40 that correspond to the predetermined area in the substrate W.
The substrate W that is a part to be plated is installed in the plating bath (S300), such that the predetermined area of the substrate W corresponds to the protrusion members 41. That is, the substrate W may be positioned on the cathode 30, so that centers of the protrusion members 41 overlap, e.g., are aligned with, centers of corresponding predetermined areas in the substrate W that require increased metal ion flow.
Next, in S400, a plating solution may be supplied using the plating solution ejection member 11, so that the plating solution contacts the substrate W in the plating bath 10. The power supply unit 50 electrically connected to the anode 20 and the cathode 30 applies a voltage, thereby forming an electric field along a direction from the anode 20 to the cathode 30.
The plating solution proceeds toward the substrate W according to the electric field and passes through the holes 40a of the paddle 40. Thus, metal ions adsorb to the surface of the substrate W that is electrically connected to the cathode 30, thereby forming a plating film on the surface of the substrate W (S400). While the plating solution passes through the holes 40a of the paddle 40, eddy flow is generated in the vicinity under each of the protrusion members 41 due to the electric field. Accordingly, flow of metal ions from the plating solution under the protrusion member 41 may be increased, thereby increasing deposition thickness of the film in regions under the protrusion members 41, i.e., rapid supply of the metal ions provides a relatively thick plating thickness in the vicinity under each of the protrusion members 41. Thus, the thickness of the plating film may be made uniform.
The plating solution supplied by the plating solution ejection member 11 to the plating bath 10 may be returned through the plating solution return line RL and resupplied to the plating bath 10 after a cleansing process (not shown).
Referring to
When the groove 43 is provided as described above, eddy flow is generated in the vicinity under the groove 43. Thus, supply of metal ions of the plating solution may be relatively increased under the groove 43, so that the plating film may have a relatively thick plating thickness in the vicinity under the groove 43. Thus, the thickness of the plating film may be made uniform by recognizing a predetermined area of a substrate where the plating thickness is relatively thin during a plating process and increasing plating solution flow through the plating solution flow reinforcement portion 43. In other words, the groove 43 in the paddle 40 according to the present exemplary embodiment may rapidly supply metal ions to the predetermined area of the substrate W.
Referring to
For example, as illustrated in
In another example, as illustrated in
Thus, the linear flow of the plating solution toward the paddle 40 may be controlled, e.g., guided, to flow linearly. When the linear flow of the plating solution is guided toward the paddle 40, scattering of the plating solution contacting the substrate W is prevented. Therefore, unwanted whirling may be restricted, thereby providing substantially uniform plating.
As described above, according to the apparatus and method for electroplating a semiconductor substrate according to the present inventive concept, plating may be made uniform overall by selectively increasing the flow of an electrolyte solution at a predetermined area, i.e., an area where a supply amount of metal ions of the electrolyte solution needs to be relatively increased. As such, uniform film thickness and composition in an overall surface of the substrate to be plated may be maintained. Thus, plating quality of a semiconductor substrate, e.g., a semiconductor wafer, in an electroplating process may be improved.
In contrast, a conventional method of controlling electroplated film thickness may include dividing an anode facing a substrate into a plurality of anodes having insulation areas, i.e., a central anode and peripheral anodes. In this state, a plating thickness may be controlled by making the plating time of the central anode shorter than that of the peripheral anodes. In another conventional method, the cathode and anode may be divided into a plurality of cathodes and anodes, so that a current mirror circuit may be formed to control and perform uniform electrodeposition over an overall surface of the substrate, i.e., via the plurality of electrodes. However, dividing the electrodes into a plurality of parts in the conventional apparatus and method may make the structure of the electroplating apparatus complicated, and may require adjustment of the apparatus for different substrate diameters, i.e., the shape and division of the electrodes may be changed in accordance with the size of the substrate. Further, a separate control of the divided anodes may require a plurality of rectifiers, thereby increasing costs.
In another conventional method, the uniformity of a plating film may be improved by controlling the flow of an electrolyte solution, i.e., by controlling the flow pressure of an electrolyte solution using a nozzle or controlling the rotation speeds of a wafer and a paddle. However, there is a limit in improving the uniformity of plating with only the control of the flow of an electrolyte solution using a nozzle or the rotation speeds of a wafer and a paddle.
Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0047188 | May 2011 | KR | national |
