Plating device and planting method

Abstract

According to the present invention, there is provided a plating apparatus which can deposit a metal plated film such as a copper layer selectively in fine recesses for interconnects, such as trenches or via holes in a circuit form. The plating apparatus of the present invention includes an electrode head (701) having an anode (704), a plating solution impregnated material (703) for holding a plating solution, and a porous contact member (702) which is brought into contact with a surface of a substrate; a cathode electrode (712) which is brought into contact with the substrate to supply current to the substrate; a pressing mechanism (709) for pressing the porous contact member of the electrode head against the surface of the substrate under a desired pressure; a power source (723) for applying plating voltage between the anode and the cathode electrode; and a control unit (721) for correlating and controlling the state for pressing the porous contact member of the electrode head against the surface of the substrate, and the state of plating voltage applied between the anode and the cathode electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to a plating apparatus and a plating method, and more particularly to a plating apparatus and a plating method used for filling a fine interconnect pattern formed in a substrate, such as a semiconductor substrate, with metal (interconnect material) such as copper so as to form interconnects. BACKGROUND ART [0002] Recently, there has been employed a circuit forming method comprising forming fine recesses for interconnects, such as trenches or via holes in a circuit form, in a semiconductor substrate, embedding the fine recesses with copper (interconnect material) by copper plating, and removing a copper layer (plated film) at portions other than the fine recesses by CMP means or the like. In this method, from the viewpoint of reducing loads on subsequent CMP, it is desirable that a copper plated film be deposited selectively in trenches or via holes in a circuit form, and that the amount of copper plated film deposited on portions ...

AI Technical Summary

Benefits of technology

[0014] It is a second object of the present invention to provide a plating apparatus and a plating method which can perform plating in such a state that an entire surface of a porous member is brought into close contact with a surface, to be plated, of the substrate uniformly, without increasing loads.

[0106] With this arrangement, the thickness of the metal film on the surface of the substrate is measured, and plating time is increased or decreased as needed by feedback of the measured results. Therefore, the metal film having a desired thickness can be formed in a good reproducibility.

Problems solved by technology

If the amount of copper to be removed is larger, then CMP requires a longer period of time, thereby causing an increased cost.

Further, if a substrate has non-uniformity on its polished surface after CMP, then interconnects remaining after polishing have different depths over the surface of the substrate.

Thus, a longer period of polishing time increases a degree of dependence of interconnect performance upon CMP performance.

These ideas can achieve the object to a certain extent but have a limitation.

On the other hand, in a method comprising bringing a porous member into contact with a substrate and plating-the substrate while relatively moving the porous member in a contact direction, a porous member, which generally has a surface roughness in a range of from several micrometers to several hundred micrometers, is problematic to planarize projections and depressions on a semiconductor substrate having a surface roughness in a range of from submicrometers to several micrometers.

However, it is difficult to obtain expected results because of the surface roughness as described above.

Further, it is difficult to uniformly press the overall surface of the porous member against the surface, to be plated, of the substrate so as to bring it into close contact with the surface of the substrate because of the surface roughness of the surface of the porous member, or undulations or warpages produced in the porous member when the porous member is pressed against the surface, to be plated, of the substrate.

Thus, plating non-uniformity is caused over the surface of the substrate.

In such a case, an extremely large load is applied to the substrate.

Accordingly, in a case where a soft insulating film such as a low-k material is processed, the insulating film is broken, and a surface of a plated film is likely to be scratched.

Thus, it has been difficult to put the above method into practice.

However, in a conventional plating apparatus in which a substrate is held and plated in such a state that a surface of the substrate faces upward (in a face-up manner), a large amount of plating solution is required to be supplied in order to continuously supply a new plating solution between the substrate (cathode) and an anode to plate the substrate.

Thus, the conventional plating apparatus has been problematic in wastefully consuming a plating solution.

However, even though the new plating solution is supplied to the substrate from the position near the substrate, the used plating solution that has been deteriorated by immersion of the anode is actually circulated and mixed into the new plating solution.

As a result, plating characteristics cannot be maintained or managed.

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