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Method for removing copper from fluid solutions

IP.com Disclosure Number: IPCOM000030152D
Publication Date: 2004-Jul-29
Document File: 2 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for removing copper from fluid solutions. Benefits include improved functionality and improved performance.

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Method for removing copper from fluid solutions

Disclosed is a method for removing copper from fluid solutions. Benefits include improved functionality and improved performance.

Background

              Conventional semiconductor fabrication processes require the use of highly pure, copper free chemicals.

      When silicon wafers are polished in two different slurries that contain ~100-ppb copper, the wafers adsorb copper on the polished surface to 100-4000e10 atoms/cm2, while the backsides remain at below 0.1e10 atoms/cm2. The silicon surface that has the native oxide removed is very capable of pulling copper out of the fluid solution, while the other surface with the native oxide adsorbs virtually none.

              Conventionally, removing copper is done by a variety of methods but all are challenged by the levels of purity required and by the directive to keep costs low.

General description

      The disclosed method creates a freshly cleaned silicon surface as an attractant for trace amounts of copper to remove it from a process fluid or gas.

              The key elements of the disclosed method include:

•             Presenting a clean silicon surface with all of the native oxide recently removed

•             Passing the copper containing fluid across the clean surface

•             Maintaining the proper chemical environment to attract the copper to the silicon

•             Replenishing the silicon source by adding new material or regenerating it

Advantages

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