Apparatus for removing native oxide layers from silicon wafers

Abstract

A method and apparatus for selectively removing a native oxide layer from a silicon wafer without significantly affecting the underlying silicon or other material, that may be thereon, by exposing the silicon wafer to an etchant gas including NF3 while simultaneously exposing the wafer to ultraviolet radiation, and heating the wafer to a temperature of 100-400° C.

Description

[0001] This application is related to Provisional Application No. 60 / 086,635, filed May 20, 1998 and claims its priority date.FIELD AND BACKGROUND OF THE INVENTION[0002] The present invention relates to a method and apparatus for selectively removing native oxide layers from silicon wafers without significantly affecting the underlying silicon, or without significantly removing other materials, such as polysilicon or thermal oxide depositions, that may be thereon. Such a process is of substantial importance to the semiconductor industry since the selective removal of native oxide from silicon wafers is among the most frequently performed processes in fabricating silicon semiconductor devices.[0003] Whenever a silicon wafer is exposed to an oxidizing environment, a native oxide layer tends to form on the silicon wafer. Such native oxide layers would deleteriously affect the subsequent processing steps performed on the silicon wafer, and therefore must be cleanly and quickly removed w...

AI Technical Summary

Benefits of technology

This method significantly increases the native oxide removal rate while maintaining selectivity over polysilicon and thermal oxide layers, with optimal results achieved at 300°C and moderate pressure, reducing processing time and avoiding health and operational hazards associated with higher pressures.

Problems solved by technology

As will be described more particularly below, it has been found that elevating the process temperature as described above substantially increases the removal rate of the native oxide without losing the selectivity achieved at room temperature until the higher end of above-described temperature range is reached At higher temperatures, the native oxide removal rate may increase further, but it was found that selectivity is lost.

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