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Method for separating copper from CMP waste streams

IP.com Disclosure Number: IPCOM000019312D
Publication Date: 2003-Sep-10
Document File: 4 page(s) / 71K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for separating copper from chemical/mechanical polish (CMP) waste streams. Benefits include improved environmental friendliness, improved performance, and improved process simplicity.

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Method for separating copper from CMP waste streams

Disclosed is a method for separating copper from chemical/mechanical polish (CMP) waste streams. Benefits include improved environmental friendliness, improved performance, and improved process simplicity.

Background

Environmental regulations require the removal of heavy metals from waste streams before they are discharged into local streams. The introduction of copper into the back end for interconnects created several waste streams laden with free copper. Conventionally, free copper must be separated from a CMP waste stream before it can be discharged into local streams. This process uses several unit operations, including ion-exchange columns, pH adjustment, and peroxide destruction (see Figure 1).

General description

The disclosed method is a process that separates copper from CMP waste by converting the slurry abrasive into an ion-exchange material. The method converts the abrasive by chemically attaching a ligand that has an ion-exchange moiety. After the ligand is attached to the abrasive surface, the material functions as an ion-exchange material and chelates all the free copper in the solution. By using this process, several unit operations are eliminated and only a simple solid/liquid separation step is required to separate the abrasive and bound copper from the waste stream. This method eliminates the use of a conventional ion-exchange column.

         The key elements of the method include:

•         In-place conversion of slurry abrasive waste into an ion-exchange matrix

•         Reaction of ligand with an ion-exchange moiety onto the abrasive surface using a coupling agent

•         Ion-exchange moiety optimization

•         Solid/liquid separation operation to discard the abrasive and bound copper

Advantages

         The disclosed method provides advantages, including:

•         Improved environmental friendliness due to eliminating the requirement for the disposal of ion-exchange resin and associated maintenance

•         Improved environmental friendliness due to eliminating the use if a waste stream to clean a heavy metal stream

•         Improved environmental friendliness due to the reuse of slurry waste into a ion-exchange material

•         Improved performanc...