Rapid Thermal Processing: When Will it Replace Batch Processing?

Abstract

Rapid Thermal Processing (RTP) is currently well established at the < 0.5 μm nodes for implant anneal and suicide formation/anneal in logic applications. Rapid Thermal Chemical Vapor Deposition (RTCVD) is being evaluated to deposit thin nitride for the DRAM storage node dielectric. A combination RTP/RTCVD has been evaluated in the form of a cluster tool to evaluate 60 Å gate oxides. These applications of RTP are considered to be process enabling because of either improved temperature ramp control or ambient control which are not available in batch processing. However, even with these specialized applications, rapid thermal processing comprises less than 20% of the front end thermal processes in a typical 0.35 μm fab. Process and equipment issues with rapid thermal processing remain which must be overcome if it is to replace batch processing at the 0.25 μm node. Process issues which are especially critical for RTCVD processing require improved temperature measurement, high growth/deposition rate, and an efficient method of cleaning the process chamber. Equipment issues are reliability and throughput which directly affect the tool cost of ownership. In this paper, each of these issues will be addressed and compared to batch processing using a generic logic process flow.