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Method for ultrafine particle extraction

IP.com Disclosure Number: IPCOM000042243D
Publication Date: 2005-Feb-03
Document File: 2 page(s) / 67K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for ultrafine particle extraction. Benefits include improved performance and improved process simplicity

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Method for ultrafine particle extraction

Disclosed is a method for ultrafine particle extraction. Benefits include improved performance and improved process simplicity.

Background

              Conventionally, oversize particles (OSP) can cause scratching in silicon wafers. Conventional slurries have OSPs that are either large particles or agglomerates of small particles. This problem is conventionally solved using depth filters that can pass OSPs. Additionally, slurry steams are monitored to ensure integrity.

      A back flow technique is conventionally used in flow through-plating systems.

      The charge on a particle is a physical property created when the particle is past its iso-static point.

Description

      The disclosed method uses a gel permeation chromatography (GPC) membrane (GPC-M) to isolate a very narrow distribution of particles for chemical mechanical planarization (CMP).

              The key elements of the disclosed method include (see Figure 1):

•             GPC membrane rather than GPC beads separate polymers based on molecular size. The membrane is tailored to whatever size distribution allows continuous separation of the particles.

•             Charged surface behind the GPC-M, which attracts charged particles on the uptake side of the separator. The opposite charge repels particles on the release side of the separator. (Particles are naturally charged on either side of their iso-electric point.)

•             Perforated walls direct a pump...