Planting process and manufacturing process for semiconductor device thereby, and plating apparatus

Abstract

An objective of this invention is to reliably form a plating film. The following two steps are sequentially conducted: step 101 of connecting a film-formation surface of a wafer 109 to a cathode electrode 107, making the film-formation surface inclined from the surface of a plating solution 103 and immersing the wafer 109 into the plating solution 103 with applying a first current between the cathode electrode 107 and an Cu anode electrode 105 disposed in the plating solution 103, and step 103 of, after immersing the film-formation surface in the plating solution 103, applying a second current between the cathode electrode 107 and the Cu anode electrode 105 to form a metal film on the film-formation surface by electrolytic plating. In step 101, the first current is controlled on the basis of an inclination angle between the liquid surface and the film-formation surface.

Description

[0001] This application is based on Japanese patent application NO. 2005-125782, the content of which is incorporated hereinto by reference. BACKGROUND [0002] 1. Technical Field [0003] This invention relates to a plating process for forming a conducting film by electrolytic plating and a process for manufacturing a semiconductor device by the plating process, as well as a plating apparatus. [0004] 2. Related Art [0005] A damascene process is one of processes for forming a Cu multilayer interconnection in an LSI. In a damascene process, a monolayer or multilayer insulating film is formed on an Si wafer with a transistor, and the insulating film is selectively removed to form a trench of an interconnection pattern and a hole called as a via for electrical connection between multilayer interconnection layers. Next, a material containing a high-melting metal called as a barrier metal is deposited by chemical vapor deposition or physical vapor deposition. Then, a Cu film called as a seed...

AI Technical Summary

Benefits of technology

[0019] After intense investigation for preventing fluctuation in a current density newly generated during inclined insertion of a wafer in a plating solution, the present inventors have found that fluctuation in a current density can be prevented by controlling a current on the basis of an inclination angle of the wafer from the liquid surface of the plating solution in the course of immersing a wafer, finally achieving this invention.

[0024] In the first step of the plating process of this invention, the wafer is inclined-inserted with applying the first current between the cathode electrode and the anode electrode and controlling the first current depending on an inclination angle of the surface between the plating solution and the film-formation surface of the wafer. Thus, it can effectively prevent fluctuation in a current density generated in the initial plating stage during the inclined insertion. It can, therefore, improve stability in the formation of a metal film and improve an yield of producing a plated film.

[0025] In the first step in the plating process of this invention, the first current applied between the anode electrode and the cathode electrode may be controlled, taking factors other than an inclination angle into account. For example, in the first step, the current may be controlled in the light of, in addition to an inclination angle, a speed in the direction of the normal line in the film-formation surface of the wafer and an elapsed time after the wafer contacts with the liquid. It can further reliably prevent fluctuation in a current density in the first step. Furthermore, in the first step, the first current may be controlled, neglecting fluctuation in an inclination angle within a given range.

[0028] In the manufacturing process of this invention, a metal film is formed on a wafer by the plating process as described above, so that even when forming a fine metal film pattern in a semiconductor device, defective burying of the metal film and local increase in a film thickness can be prevented, resulting in stable film formation. Thus, an yield in manufacturing a semiconductor device can be improved.

[0037] The plating apparatus according to this invention has a configuration where the wafer holding unit holds the film-formation surface at an inclined angle to the liquid surface and the controller controls a current intensity on the basis of the inclination angle. Thus, the configuration can effectively prevent fluctuation in a current density generated during inclined insertion with allowing for stably inclined-inserting the wafer.

Problems solved by technology

However, after investigating the method described in Japanese Patent Application No. 2003-129297, the present inventors have found that stable film formation is difficult in spite of prevention of bubble adherence by inclined insertion of a wafer.

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