Method and apparatus for cleaning substrate

Abstract

A substrate is cleaned by performing a scrubbing process on a surface to be cleaned of the rotating substrate with a roll-shaped cleaning member while holding an outer circumferential surface of the roll-shaped cleaning member in contact with the surface to be cleaned of the substrate across a predetermined contact width. During at least a part of the scrubbing process, the roll-shaped cleaning member is placed at an offset cleaning position where the central axis of the roll-shaped cleaning member is spaced from the central axis of the substrate by a distance which is 0.14 to 0.5 times the contact width. The surface to be cleaned of the substrate is scrubbed with more uniform cleaning intensity while taking into account the cleaning intensity at each position (area) along the radial direction of the surface to be cleaned of the substrate.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a method and an apparatus for cleaning a substrate by scrubbing a surface to be cleaned of the substrate while the substrate is in rotation with a roll-shaped cleaning member, such as a roll brush, a roll sponge, or the like, which is being held in contact with the surface to be cleaned of the substrate.[0003]2. Description of the Related Art[0004]As semiconductor devices are finding themselves integrated to increasingly higher levels, there is a demand in the art for the development of a cleaning technology for highly cleaning an entire surface (front surface and / or back surface) of substrates in order to achieve a high yield of product substrates. For example, CMP (Chemical Mechanical Polishing) processes, which are performed to planarize insulating films, produce STIs (Shallow Trench Isolations), form tungsten plugs, and form multilayer copper interconnects, generally employ a contact...

AI Technical Summary

Benefits of technology

This approach ensures more uniform cleaning intensity, preventing local interconnect corrosion and surface irregularities, thereby enhancing the cleaning efficiency and reliability of semiconductor devices.

Problems solved by technology

When substrates having devices of smaller dimensions are polished, metal interconnects that are exposed by the polishing process may possibly be chemically or electrochemically corroded under etching forces of chemicals used and mechanical forces.

Such metal interconnect corrosions are considered to adversely affect the reliability of the devices significantly.

As a result, the cleaning intensity over the entire surface of the substrate suffers irregularities due to the different contact densities, making it difficult for the scrubbing process to meet desired cleaning requirements.

The failure to meet the desired cleaning requirements has a detrimental effect on efforts to prevent, e.g., local interconnect corrosions on the surface of the substrate.

However, since the roll brush is mounted on a polishing apparatus in a fixed positional relationship to the substrate according to any of the above proposals, it is conceivable that the distribution of cleaning intensities over the surface to be cleaned of the substrate cannot be adjusted as desired depending on the conditions under which the roll brush and the substrate rotate about their own axes.

Consequently, even though the front surface (surface to be cleaned) of the substrate is cleaned by the roll-shaped cleaning member while the surface to be cleaned of the substrate is moving back and forth parallel to the roll-shaped cleaning member, or even though the upper roll brush and the lower roll brush are disposed such that axes of the upper roll brush and the lower roll brush extend parallel to each other and are biased perpendicularly to the central axis about which the substrate rotates, it is considered difficult to scrub the entire surface to be cleaned of the substrate with more uniform cleaning intensity.

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