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Advances in rapid thermal and integrated processing
ELSEVIER
Microelectronic
Engineering
34 ( 1997) 215-2 16
Advances in rapid thermal and integrated processing NATO ASI Series E: Applied Sciences Vol. 318. Fred Roozeboom (editor), Kluwer Academic Publishers, 1996. ISBN o-7923-401 l-6. This book gives an accurate and comprehensive picture of the current state of Rapid Thermal Processing (RTP) science, technology and application. There is a wealth of data and information, made accessible through a useful subject index. The 19 individually-authored chapters span a wide range of topics and treatments, from reviews on all the key aspects of RTP, to accounts of individual research. What emerges is a clear picture of a field in which the science is much better understood and equipment simulation and engineering has matured. As a consequence of this and specific initiatives, equipment prototypes now exist which make real manufacturability possible for a much wider range of the RTP applications to integrated circuit (ULSI) fabrication developed by researchers over the past 18 years. Recent closer cooperation between industrial RTP users, equipment developers and research groups has revealed the stringency of the ULSI manufacturing specifications, identified routes to achieving them, and resulted in a number of novel and interesting developments in equipment design and integration. For those new to the field, the first chapter is an excellent introduction to all aspects. The scientific key to these developments has been fully understanding the spatial and -temporal dependence of wafer temperature on the complex interactions between the light sources, the cavity, the gaseous ambient and the patterned wafer, all of which are non-uniform in three dimensions. These aspects are well explained in the chapters on Thermal Radiation, Temperature and Process Control, and Modelling Strategies. The application of RTP to a wide range of ULSI process steps. and the specification that these imply for an RTP system are well covered, including excellent chapters on surface cleaning, oxidation and nitridation, chemical deposition of Si and SiGe, silicidation, and deep submicron CMOS processing. Other potential applications of RTP are not forgotten, and include photovoltaic panels, compound semiconductor devices, and magnetic thin films. The developments in equipment, resulting from matching an industry need for single wafter cluster tools with the new understanding, capabilities and engineering of RTP, show the biggest advance in the maturity of RTP since the last comparable survey of RTP in 1993. Many of the continuing trends of ULSI technology, including increasing wafer size, lower allowable thermal budget, and increased use of single wafer cluster tools for quick processing turnround, are shown to favour RTP over conventional furnacing. What has needed improving is the control and repeatability of the spatial and temporal heat-treatment experienced by the wafer under manufacturing conditions. Two chapters describe how specific initiatives have addressed and found solutions to these problems. Rapid Thermal Multiprocessing makes clear the limitations of previously available lamp arrays as heating sources, and pyrometers/ thermocouples as temperature sensors, and is fascinating for the novel solutions adopted, which include programmable point source lamp arrays and acoustic thermometers. Single0167.9317/97/$17.00 Published by Elsevier Science B.V. All rights reserved PII SOl67-9317(97)00004-X
216
Book
review
/ M’icrorlectrmic
Engineering
34
(1997)
215%216
wafer Process Integration concentratets on the different machine specifications imposed by the main ULSI process steps, and gives insight into the way in which one equipment supplier has incorporated these into cluster tool design, so as to allow integration of up to five RTP process steps. The book has both the strengths and weaknesses associated with the compilation of paper:< from an interactive event, in this case, a NATO Advanced Study Institute. On the positive side, the coverage of the field is comprehensive and up-to date, given by workers closely involved in the deve.iopments, whose enthusiasm and deep knowledge of their subjects shows through. On the negative side, there is quite a lot of repetition of basic principles, and one or two chapters are not of the excellent standard set by the majority. As a whole, the book is a most useful update of the field, and can be recommended both as an introduction to the subject and for reference. Chris Hill GEC-Marconi GMMT Caswell
Microelectronic
Engineering
34 ( 1997) 215-2 16
Advances in rapid thermal and integrated processing NATO ASI Series E: Applied Sciences Vol. 318. Fred Roozeboom (editor), Kluwer Academic Publishers, 1996. ISBN o-7923-401 l-6. This book gives an accurate and comprehensive picture of the current state of Rapid Thermal Processing (RTP) science, technology and application. There is a wealth of data and information, made accessible through a useful subject index. The 19 individually-authored chapters span a wide range of topics and treatments, from reviews on all the key aspects of RTP, to accounts of individual research. What emerges is a clear picture of a field in which the science is much better understood and equipment simulation and engineering has matured. As a consequence of this and specific initiatives, equipment prototypes now exist which make real manufacturability possible for a much wider range of the RTP applications to integrated circuit (ULSI) fabrication developed by researchers over the past 18 years. Recent closer cooperation between industrial RTP users, equipment developers and research groups has revealed the stringency of the ULSI manufacturing specifications, identified routes to achieving them, and resulted in a number of novel and interesting developments in equipment design and integration. For those new to the field, the first chapter is an excellent introduction to all aspects. The scientific key to these developments has been fully understanding the spatial and -temporal dependence of wafer temperature on the complex interactions between the light sources, the cavity, the gaseous ambient and the patterned wafer, all of which are non-uniform in three dimensions. These aspects are well explained in the chapters on Thermal Radiation, Temperature and Process Control, and Modelling Strategies. The application of RTP to a wide range of ULSI process steps. and the specification that these imply for an RTP system are well covered, including excellent chapters on surface cleaning, oxidation and nitridation, chemical deposition of Si and SiGe, silicidation, and deep submicron CMOS processing. Other potential applications of RTP are not forgotten, and include photovoltaic panels, compound semiconductor devices, and magnetic thin films. The developments in equipment, resulting from matching an industry need for single wafter cluster tools with the new understanding, capabilities and engineering of RTP, show the biggest advance in the maturity of RTP since the last comparable survey of RTP in 1993. Many of the continuing trends of ULSI technology, including increasing wafer size, lower allowable thermal budget, and increased use of single wafer cluster tools for quick processing turnround, are shown to favour RTP over conventional furnacing. What has needed improving is the control and repeatability of the spatial and temporal heat-treatment experienced by the wafer under manufacturing conditions. Two chapters describe how specific initiatives have addressed and found solutions to these problems. Rapid Thermal Multiprocessing makes clear the limitations of previously available lamp arrays as heating sources, and pyrometers/ thermocouples as temperature sensors, and is fascinating for the novel solutions adopted, which include programmable point source lamp arrays and acoustic thermometers. Single0167.9317/97/$17.00 Published by Elsevier Science B.V. All rights reserved PII SOl67-9317(97)00004-X
216
Book
review
/ M’icrorlectrmic
Engineering
34
(1997)
215%216
wafer Process Integration concentratets on the different machine specifications imposed by the main ULSI process steps, and gives insight into the way in which one equipment supplier has incorporated these into cluster tool design, so as to allow integration of up to five RTP process steps. The book has both the strengths and weaknesses associated with the compilation of paper:< from an interactive event, in this case, a NATO Advanced Study Institute. On the positive side, the coverage of the field is comprehensive and up-to date, given by workers closely involved in the deve.iopments, whose enthusiasm and deep knowledge of their subjects shows through. On the negative side, there is quite a lot of repetition of basic principles, and one or two chapters are not of the excellent standard set by the majority. As a whole, the book is a most useful update of the field, and can be recommended both as an introduction to the subject and for reference. Chris Hill GEC-Marconi GMMT Caswell