Materials Science Forum Vols. 573-574

Abstract: Various types of conduction-based RTP systems are discussed. It is shown that simple hot plate systems suffer from severe bow of the wafer, when placed directly on the susceptor. This results in non-uniform heating. A solution is to place the wafer on pins; however, this considerably reduces the heat-up rate. An effective way to heat wafers through conduction fast and wellcontrolled is by placing it in a so-called gas bearing, an arrangement in which the wafer floats in between two hot blocks, at a well-controlled, small distance from both blocks. The heat-up rate in this so-called Levitor system is very high (~900°C/s) and uniform. It is demonstrated that this conduction-based system does not suffer from non-uniformities caused by variations in emissivity and/or pattern density across-wafer or within-die. In a direct comparison on pattern-dependent heating effects, substrates with trenches with varying dimensions are spike-annealed in a state-ofthe- art lamp system and in the Levitor. It was shown that temperature non-uniformities in the lampbased and the conduction-based systems are > 40°C and < 1°C, respectively. The conclusion is that the Levitor provides emissivity and pattern-independent heating.

Abstract: We have extensively studied the impact of advanced annealing schemes for highperformance SOI logic technologies. Starting with the 130 nm technology node, we introduced spike rapid thermal annealing (sRTA). Continuous temperature reduction combined with implant scaling helped to improve transistor performance and short channel behavior. During the development of the 90 nm technology we evaluated flash lamp and laser annealing (FLA). These techniques became an essential part of the 65 nm node. At this node we also faced major challenges in terms of compatibility with new materials like SiGe as well as the need for reduction of process parameter fluctuations. Scaling will be continued with the 45 nm technology node towards a truly diffusionless process.

Abstract: Temperature measurement by means of a pyrometer is affected by changes in the background illumination. Physical modeling is a very effective method to discern the origin of radiation contributions and separate the thermal radiation emitted by the object of interest from parasitic radiation. An observer algorithm making use of physical models was successfully applied to infrared pyrometry for rapid thermal processing. Rapid thermal processing is characterized by fast temperature changes in the range of several hundred degree per second. The heating source typically emits light within a broad wavelength band ranging from visible to infrared. Especially in rapid thermal processors that apply heat to both sides of a silicon wafer, this light is partially picked up by the pyrometer sensor. As a consequence these types of systems require methods to handle the fast changing radiation contribution of the heating source to the pyrometer signal.

Abstract: There is a clear and increasing interest in short time thermal processing far below one second, i.e. the lower limit of RTP (Rapid Thermal Processing) called spike annealing. It is the world of processing in the millisecond or nanosecond range. This was driven by the need of suppressing the so-called Transient Enhanced Diffusion in advanced boron-implanted shallow pnjunctions in the front-end silicon chip technology. Meanwhile the interest in flash lamp annealing (FLA) in the millisecond range spread out into other fields related to silicon technology and beyond. This paper reports shortly about the restart in flash lamp annealing of the Rossendorf group in collaboration with the Mattson group and further on recent experiments regarding shallow junction engineering in germanium, annealing of ITO (indium tin oxide) layers on glass and plastic foil to form an conductive layer as well as investigations which we did during the last years in the field of wide band gap semiconductor materials (SiC, ZnO). Moreover recent achievements in the field of silicon-based light emission basing on Metal-Oxide-Semiconductor Light Emitting Devices will be reported. Finally it will be demonstrated that the basic principle of short time thermal processing, i.e. surface heating on a colder bulk, features also advantages regarding the casting of lead sheets to produce organ pipes in the spirit of the 17th century.