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Gas Phase Surface Incorporation Techniques for the Preparation of Surface Level Metallic Contamination Standards

IP.com Disclosure Number: IPCOM000042250D
Publication Date: 2005-Feb-03
Document File: 3 page(s) / 43K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses gas phase surface incorporation (GAPSINC) techniques; this method uses dry gas phase plasma systems to produce surface-level metallic contamination standards over any substrate material. Benefits include producing wafers with good uniformity, a wide range of density levels, and a longer shelf life.

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Gas Phase Surface Incorporation Techniques for the Preparation of Surface Level Metallic Contamination Standards

Disclosed is a method that uses gas phase surface incorporation (GAPSINC) techniques; this method uses dry gas phase plasma systems to produce surface-level metallic contamination standards over any substrate material. Benefits include producing wafers with good uniformity, a wide range of density levels, and a longer shelf life.

Background

Device reliability and yield are adversely affected by the presence of transition and alkali metals. The acceptable density level of these elements on the surface of silicon wafers is diminishing because of the increasing complexity and integration of nanometer scale devices. As a consequence, more accurate standards and sensitive analytical methodologies are required to control the cleanliness of the wafer surface during device processing, especially in the front end process.

Currently, it is difficult to produce reliable surface-level metallic contamination standard wafers with extended shelf lives and a wide range of density levels. Current methods use wet processing techniques, and require the wafers to dry after dipping them in strong acids or alkalis (see
Figure 1). Drying the wafers creates an uneven distribution of metals, resulting in poor within-wafer uniformity and difficulties in selectively incorporating the metals at specific density levels.

General Description

The disclosed method is based on the GAPSINC of desired metals onto silicon, or any other substrate. Figure 2 shows the initial dry etching step on a known metal source, either in the form of bulk metal or in the form of thin metal layers over any substrate. This etch process occurs in a  low pressure plasma environment, in the presence of reactive gases (i.e. fluoro-carbon mixtures, oxy...