Polishing apparatus and polishing method

Abstract

A polishing apparatus polishing a surface of a substrate, such as a semiconductor substrate. The polishing apparatus including a substrate holding mechanism, a polishing table having a polishing surface, and a polishing surface temperature controller for controlling a temperature distribution of the polishing surface. The substrate holding mechanism and the polishing table provide relative movement between the surface of the substrate and the polishing surface while the substrate holding mechanism presses the surface of the substrate against the polishing surface to thereby polish the surface of the substrate. The polishing surface temperature controller controls the temperature distribution so that the polishing surface has a predetermined temperature distribution to thereby control removal rates of portions of the surface of the substrate.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a polishing apparatus and a polishing method for polishing a substrate, such as a semiconductor substrate, by operating a substrate holding mechanism so as to bring the substrate into contact with a polishing surface of a polishing table and by providing relative movement between a surface of the substrate and the polishing surface.[0003]2. Description of the Related Art[0004]A chemical mechanical polishing (CMP) apparatus has been known as an apparatus for polishing a substrate, e.g., a semiconductor substrate. This type of polishing apparatus includes a polishing table, a polishing cloth (polishing pad), and a substrate holding mechanism (top ring) for holding a substrate. The polishing cloth is attached to an upper surface of the polishing table to form a polishing surface. A substrate to be polished (hereinafter referred to as a substrate), such as a semiconductor substrate, is press...

AI Technical Summary

Benefits of technology

[0009]The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a polishing apparatus and a polishing method which can obtain a uniform polishing profile while keeping a high removal rate even in a CMP process in which a removal rate greatly depends on a temperature of a polishing surface.

[0010]In order to solve the above drawbacks, one aspect of the present invention provides a polishing apparatus comprising a substrate holding mechanism for holding a substrate, a polishing table having a polishing surface, and a polishing surface temperature controller for controlling a temperature distribution of the polishing surface. The substrate holding mechanism and the polishing table are operable to provide relative movement between the surface of the substrate and the polishing surface while the substrate holding mechanism presses the surface of the substrate against the polishing surface to thereby polish the surface of the substrate. The polishing surface temperature controller controls the temperature distribution so that the polishing surface has a predetermined temperature distribution to thereby control removal rates of portions of the surface of the substrate.

[0011]According to the present invention described above, even in a CMP process in which the removal rate greatly depends on the temperature of the polishing surface, the removal rates of the portions of the surface can be controlled as desired without lowering pressure applied to the surface of the substrate in its entirety. As a result, a uniform polishing profile can be obtained while maintaining a high removal rate of the surface of the substrate.

Problems solved by technology

However, a polishing rate (removal rate) of the surface of the substrate is affected not only by contact pressure acting between the substrate and the polishing surface, but also by a temperature of the polishing surface, a concentration of the polishing liquid (i.e., slurry) to be supplied, and the like.

Accordingly, adjustment of the contact pressure is not enough to completely control the removal rate.

Particularly, in a CMP process in which a removal rate greatly depends on a temperature of the polishing surface (for example, in a case where a surface hardness of a polishing cloth greatly depends on a temperature thereof), the removal rate would vary from area to area of the surface of the substrate depending on a temperature distribution, and as a result, a uniform polishing profile cannot be obtained.

Generally, the temperature distribution of the polishing surface is not uniform, and there are temperature differences between areas within the polishing surface.

The non-uniform distribution and temperature differences are a result of several causes, including heat generated from the polishing surface itself due to contact with a retainer ring provided on the top ring for holding the substrate, non-uniform heat absorptivity of the polishing surface, and current directions of the slurry supplied to the polishing surface.

As a result, non-uniformity of the removal rate within the surface cannot be resolved.

That is, only adjustment of the contact pressure cannot provide a uniform polishing profile of the surface in its entirety.

However, the removal rate of the surface of the substrate is lowered in its entirety, and hence productivity is decreased.

Thus, it is difficult to obtain a uniform polishing profile while maintaining a high removal rate.

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