A new VLSI compatible rapid thermal processing system

Abstract

Rapid thermal processing (RTP) is increasingly becoming a significant tool to meet the challenge of fabricating miniaturized MOS and bipolar devices. The primary advantages of RTP over conventional furnace annealing include the shorter heat cycle, well-controlled soak times at peak temperatures and the capability to rapidly change anneal ambients, thereby enhancing its flexibility as a process tool. The major applications of RTP in VLSI technology that are presently being pursued include: (i) implant-damage annealing/dopant activation, (ii) silicide formation, (iii) glass reflow, (iv) thin film growth/deposition (oxides, nitrides, oxy-nitrides) and (v) contact alloying. This paper discusses a new rapid thermal processor, RTP-800/8000, recently introduced by Varian. The discussion will include mechanical and electrical design, software, heating process compatibility, process uniformity and repeatability, process setup and noncontact temperature measurement. The heating system consists of a tungsten lamp array surrounded by a highly reflective mirror system designed to provide good temperature uniformity for wafer sizes up to 200 mm. The RTP-8000 has a serial cassette-to-cassette automatic wafer handling system. The RTP-800 possesses a single wafer, operator-assisted wafer handling system. The RTP-800/8000 has an automated multiple gas flow control and also has the optional capability of processing wafers in vacuum. An infrared optical pyrometer measures the wafer temperature from the backside of the wafer. In the RTP-8000, touch screen operation of the menu-driven recipes is easy with user-friendly software. A separate electroluminescent flat panel display provides information for maintenance and servicing and reports the system status. Process information is provided on this display in the RTP-800.