Method of recycling abrasive slurry

a technology of abrasive slurry and slurry, which is applied in the direction of metal-working equipment, lapping machines, manufacturing tools, etc., can solve the problems of insufficient application of documents in retrieving and recycling, inability to solve all problems, and easy blockage of filters by aggregation, so as to reduce the manufacturing cost of semiconductor wafers and reduce the use of slurry

Inactive Publication Date: 2009-02-26
SUMCO TECHXIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0015]An object of the invention is to provide a method of recycling an abrasive slurry, by which a used slurry having been used in polishing semiconductor wafer(s), particularly a slurry having been used in finish polishing, can be recycled, so that considerable reduction in slurry usage can contribute to reduction in manufacturing cost of the semiconductor wafer(s).

Problems solved by technology

However, the methods disclosed in the above Documents are not sufficiently applicable in retrieving and recycling the above-described colloidal silica slurry, and the following problems are pertinent to the methods.
Thus, even when the slurry experiences filtration by a filter, such gel-like aggregation can easily clog the filter.
The methods disclosed in the above Documents cannot solve all the problems although the methods may be able to solve one of the problems.

Method used

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  • Method of recycling abrasive slurry

Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0061]After a slurry prepared by diluting a stock solution with water 20 times was used for polishing for 500 minutes, the used slurry was irradiated with ultrasound and subsequently filtrated by the foreign-substance filtrating filter 6 for removal of foreign substances. Then, a reproduced slurry was obtained.

experiment example 2

[0062]The same used slurry as in the experiment example 1 was added with ammonia water as a dispersant, irradiated with ultrasound and filtrated by the foreign-substance filtrating filter 6 for removal of foreign substances. Then, a reproduced slurry was obtained.

experiment example 3

[0063]The same used slurry as in the experiment example 1 was added with KCl water as a dispersant, irradiated with ultrasound and filtrated by the foreign-substance filtrating filter 6 for removal of foreign substances. Then, a reproduced slurry was obtained.

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Abstract

A method of recycling an abrasive slurry for recycling a slurry that: contains colloidal silica; and has been used in polishing semiconductor wafer(s) is provided. The method includes: adding a dispersant to the used slurry having been collected so as to prevent the used slurry from being gelled; irradiating ultrasound to the used slurry having been added with the dispersant so as to disperse a gelled portion and aggregated silica in the used slurry; and, by using a filter, removing a foreign substance contained in the used slurry having been irradiated with the ultrasound.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a method of recycling an abrasive slurry for recycling a used slurry having been used in polishing semiconductor wafer(s).[0003]2. Description of Related Art[0004]Polishing of semiconductor wafer(s) is generally classified into two major categories of rough polishing and finish polishing according to surface roughness to be made on the semiconductor wafer(s).[0005]In finish polishing, where ultra-fine surface roughness is required to be made, the semiconductor wafer(s) is usually polished with an ammonia-base colloidal silica slurry having been added with a water-soluble polymer such as ethylcellulose.[0006]The colloidal silica slurry having been used in finish polishing has conventionally been discarded because the slurry may contain metal contamination originating from components of a polishing apparatus, a giant silica solid formed by aggregation of silica in the slurry, and the like....

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B24B57/00
CPCB24B57/00B24B37/0056
Inventor KOZASA, KAZUAKIGOTOU, ISAMU
Owner SUMCO TECHXIV
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