Plating apparatus and plating method

Abstract

A plating apparatus is used for filling a fine interconnect pattern formed in a substrate with metal to form interconnects. The plating apparatus includes a cathode unit having a seal member for hermetically sealing a peripheral portion of a surface, to be plated, of the substrate and a cathode electrode which is brought into contact with the substrate to supply current to the substrate; an electrode head disposed so as to be movable toward and away from the surface to be plated and having an anode and a porous member with water retentivity at upper and lower parts of the electrode head; a pressing mechanism for pressing the porous member against the surface, to be plated, of the substrate under a desired pressure; and a driving mechanism for making a relative motion between the porous member and the substrate while the porous member and the surface, to be plated, of the substrate are brought into contact with each other.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] 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 circuit pattern formed in a substrate, such as a semiconductor substrate, with metal (interconnect material) such as copper so as to form interconnects. [0003] 2. Description of the Related Art [0004] 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...

AI Technical Summary

Benefits of technology

[0010] The present invention has been made in view of the above circumstances. It is therefore an object of the present invention to provide a plating apparatus and a plating method which can easily form a plated film having a flat surface and a good quality.

[0012] According to the present invention, while the porous member and the surface, to be plated, of the substrate held by the substrate stage are brought into contact with each other, the porous member and the substrate make a relative motion, and then plating is performed, whereby plating can be suppressed in the upper part of the interconnect pattern for thereby lowering a plating rate. Thus, the plating rate in the upper part of the interconnect pattern is smaller than that in the inner part of the interconnect pattern, and the height of a plated film in the inner part of the interconnect pattern is allowed to catch up with the height of a plated film in the upper part of the interconnect pattern regardless of variations of the shape of the interconnect pattern, and hence the plated film whose surface is flat can be formed. Further, special current condition and special additives are not necessary, and the surface of the plated film is not required to be shaved, and thus the plated film of good quality can be obtained.

[0018] With the above arrangement, the porous member and the substrate held by the substrate stage make a relative motion so that contact and non-contact between the porous member and the surface, to be plated, of the substrate are repeated, and then plating is performed. In this case also, plating can be suppressed in the upper part of the interconnect pattern for thereby lowering a plating rate, and the plating rate in the upper part of the interconnect pattern is smaller than that in the inner part of the interconnect pattern, and hence a plated film whose surface is flat can be formed.

Problems solved by technology

However, in the prior art, when plating is performed, the amount of plated material is different in regions of the surface of the substrate depending on the shape of the interconnect pattern under the influence of distribution of current density or the influence of additives, and hence it is difficult to form a plated film having a uniform thickness over the entire surface of the substrate.

When plating is performed according to such method, more amount of plated material than necessary is deposited, and hence low material cost increases and a longer period of plating time is required.

These ideas or attempts can achieve the object to a certain extent but have a limitation such as a plated film of poor quality.

Images