Apparatus for cleaning a substrate having metal interconnects

Abstract

The present invention relates to a cleaning apparatus which can reduce a potential difference between metals or alloys used to form interconnects on a substrate for thereby minimizing corrosion which may occur during and after a substrate cleaning process. The cleaning apparatus for cleaning a substrate having metal interconnects comprises a cleaning mechanism for cleaning the substrate, and a functional water supply mechanism for supplying functional water to the cleaning mechanism. The cleaning mechanism cleans a surface of the substrate with use of the functional water.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a cleaning apparatus for cleaning a substrate having metal interconnects for use in a precision electronic component such as a semiconductor device, and more particularly to a cleaning apparatus which can reduce a potential difference between metals or alloys used to form interconnects on a substrate for thereby minimizing corrosion which may occur during and after a substrate cleaning process. [0003] 2. Description of the Related Art [0004] Aluminum (Al) has been widely used as an interconnect material in a semiconductor device. Aluminum or aluminum alloy is a base metal having an extremely low potential compared with other metals (see “Metal Guidebook”, p 877, edited by The Japan Institute of Metals). Accordingly, when aluminum or aluminum alloy is used in combination with copper (Cu), tungsten (W), titanium (Ti), or their alloys, such aluminum or aluminum alloy is highly liable to...

AI Technical Summary

Benefits of technology

[0011] Therefore, there has been demand for a cleaning apparatus which can prevent interconnects made of aluminum or aluminum alloy on a substrate from being corroded, and it is an object of the present invention to provide such a cleaning apparatus.

[0012] Inventors of the present invention have made diligent studies in order to solve a problem of corrosion which occurs during a cleaning process of a substrate due to a potential difference between an interconnect metal such as aluminum or the like and a barrier layer metal on the substrate. As a result, the inventors have found that the potential difference between the interconnect metal and the barrier layer metal can be reduced by using various types of functional water as cleaning water for cleaning the substrate instead of using pure water, and have completed the present invention based on the findings in that the functional water is effective to prevent the corrosion from proceeding.

[0027] From the viewpoint of the potential difference between aluminum and another metal, the potential differences between aluminum and titanium and between aluminum and titanium alloy are minimized when using the oxygen-gas-dissolved water or a mixture of the oxygen-gas-dissolved water and the hydrogen-gas-dissolved water. Similarly, the oxygen-gas-dissolved water or a mixture of the oxygen-gas-dissolved water and the hydrogen-gas-dissolved water is effective for aluminum.

Problems solved by technology

Accordingly, when aluminum or aluminum alloy is used in combination with copper (Cu), tungsten (W), titanium (Ti), or their alloys, such aluminum or aluminum alloy is highly liable to suffer corrosion due to potential difference.

Therefore, if aluminum or aluminum alloy which basically comprises Al—Cu, and the above metal such as tungsten, titanium, or copper, or their alloys are simultaneously exposed on a surface of a semiconductor device and such a semiconductor device is processed, aluminum or aluminum alloy which basically comprises Al—Cu is highly likely to suffer corrosion.

However, there arises a problem that the aluminum interconnects are corroded in the cleaning process.

When the pure water is supplied to the aluminum interconnects and the barrier metal during the cleaning process, the aluminum interconnects suffer a serious problem in that the aluminum interconnects are corroded and dissolved due to the potential difference between the aluminum interconnects and the barrier metal which have been joined to each other.

However, if the substrate has fine circuit interconnects thereon, then the corrosion may cause defects such as disconnection, and hence the above problem becomes serious.

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