Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2000-11-07
2003-12-09
Valentine, Donald R. (Department: 1742)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C118S428000, C118S429000
Reexamination Certificate
active
06660139
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plating apparatus and method, and more particularly to a plating apparatus and method for filling interconnection grooves formed in a semiconductor substrate or the like with metal such as copper.
2. Description of the Related Art
Generally, aluminum or aluminum alloy has been surface of a semiconductor substrate. The higher integration of integrated circuits on the semiconductor substrate requires that a material having a higher electric conductivity should be used for interconnection circuits. Therefore, there has been proposed a method comprising plating a surface of a substrate to fill interconnection patterns formed in the substrate with copper or copper alloy.
Various methods such as chemical vapor deposition (CVD) process, sputtering process, and the like have been used to fill interconnection patterns formed in a substrate with copper or copper alloy. However, when a metallic layer on a substrate is formed of copper or copper alloy, i.e., when copper interconnections are formed on the substrate, the CVD process requires high cost, and, if an aspect ratio is high (i.e., the depth of the pattern is larger than the width), then it is difficult to fill the interconnection patterns with copper or copper alloy in the sputtering process. Therefore, the aforementioned plating method is most effective to fill interconnection patterns formed in a substrate with copper or copper alloy.
There are various methods for plating a surface of a semiconductor substrate with copper. For example, in a cup-type plating method, a dip-type plating method, or the like, a plating container always holds a plating solution, and a substrate is dipped into the, plating solution. In another plating method, a plating container holds a plating solution only when a substrate is fed into the plating container. Further, in an electrolytic plating method, an electric potential difference is applied to plate a substrate. On the other hand, in an electroless plating method, an electric potential difference is not applied.
A conventional plating apparatus for plating a substrate with copper in these methods comprises a plating unit for plating a substrate, and, in addition, a plurality of supplementary units such as a cleaning unit for cleaning and drying a plated substrate and a transfer robot horizontally disposed for transferring a substrate between these units. The substrate is transferred between these units. A predetermined process is performed in each of units, and then the substrate is transferred to a next unit.
However, with the conventional plating apparatus, since it is difficult to efficiently dispose units for plating a substrate or performing its supplementary process in one housing unit, the conventional plating apparatus requires a large space to be installed in order to continuously plate the substrate in the housing unit. Further, for example, when the substrate is plated in a housing unit having a clean atmosphere, chemicals used in the plating process are diffused as chemical mist or gas and hence attached to a processed substrate.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a plating apparatus and method which comprises a plurality of units (pieces of equipments) disposed efficiently in one housing unit for continuously plating a substrate, and can hence reduce a space to be installed, and can prevent the substrate from being contaminated with chemicals used in the plating process.
According to a first aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-treatment unit for pre-treating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-treated in the pre-treatment unit. A first substrate stage is disposed between the cassette stage and the pre-treatment unit for holding a substrate placed thereon. A cleaning and drying unit is disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with pure water and drying the substrate. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the first substrate stage, and a second transfer device transfers a substrate between the first substrate stage, the pre-treatment unit, and the plating unit.
With this construction, a substrate is pre-treated and plated after being taken out of the substrate cassette, and then cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
According to a second aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-treatment unit for pre-treating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-treated in the pre-treatment unit. A first substrate stage is disposed between the cassette stage and the pre-treatment unit for holding a substrate placed thereon, and a chemical liquid cleaning unit disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with chemical liquid. A cleaning and drying unit is disposed between the cassette stage and the chemical liquid cleaning unit for cleaning a plated substrate with pure water and drying the substrate, a second substrate stage is disposed between the chemical liquid cleaning unit and the cleaning and drying unit for holding a substrate placed thereon. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the second substrate stage, a second transfer device transfers a substrate between the first substrate stage, the pre-treatment unit, and the plating unit, and a third transfer device transfers a substrate between the first semiconductor stage, the chemical liquid cleaning unit, and the second substrate stage.
With this construction, a substrate is pre-treated and plated after being taken out of the substrate cassette, and then cleaned with chemical liquid. Thereafter, the substrate is cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
In a preferred aspect of the present invention, at least one of the first substrate stage and the second substrate stage comprises two substrate stages, and at least one of the two substrate stages in the at least one of the first substrate stage and the second substrate stage is constituted so as to place a substrate thereon and clean the substrate. With this construction, at least one of a plated substrate and a substrate cleaned with chemical liquid can be placed on and cleaned in the substrate stage having a cleaning function, and can then be transferred to a next unit.
In a preferred aspect of the present invention, the housing unit has a partition wall for dividing the housing unit into a plating section and a clean section. The plating section has the pre-treatment unit, the plating unit, the fist substrate stage, and the second transfer device therein. The clean section has another unit therein. The partition wall has a shutter for passing a substrate therethrough; air can individually be supplied into and exhausted from each of the plating section and the clean section, and the pressure of the clea
Ozawa Naomitsu
Sendai Satoshi
Tomioka Kenya
Tsuda Katsumi
Ebara Corporation
Valentine Donald R.
Wenderoth , Lind & Ponack, L.L.P.
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