idi classroom ) CHEMICAL REACTION ENGINEERING APPLICATIONS IN NON-TRADITIONAL TECHNOLOGIES A Textbook Supplement PHILLIP E. SAVAGE, STEVEN BLAINE University of Michigan ond approach is to incorporate examples dealing with Ann Arbor, MI 48109-2136 non-traditional technologies in each of the core un­ dergraduate courses. This second approach has the ecent years have witnessed an expansion of advantage of more easily integrating the new tech­ R chemical engineering activity in areas such as nologies with fundamental principles and obviating materials processing (e.g., microelectronics, super­ the need to find additional room in an already conductors, composites) and biotechnology. This crowded curriculum. expansion has been accompanied by a reduction in A barrier to weaving examples from new tech­ chemical engineering opportunities in the more tra­ nologies into existing courses, however, is that most ditional areas of petroleum processing and commod­ chemical engineering textbooks, though good at pre­ ity chemicals. senting fundamental principles, generally do not These events have led to much introspection in provide examples and applications from non­ the chemical engineering community. One effect on traditional technologies. Thus, the instructor is forced education has been a new and widely-recognized to identify and develop such examples on his own. In need to broaden the technological base of under­ some cases the problem has been recognized and graduate education. Students must be exposed to steps have been taken to provide instructors with chemical engineering applications in the frontier useful materials. A good example is the book Chemi­ areas in addition to continued exposure to applica­ cal Engineering Education in a Changing Environ­ tions in traditional petroleum processing and petro­ ment1 11 which provides the proceedings of a confer­ chemical applications. ence sponsored jointly by the Engineering Founda­ tion, the National Science Foundation, and the Ameri­ One approach to providing the necessary expo­ can Institute of Chemical Engineers. It presents a sure is to develop elective courses dealing with spe­ large number of problems that deal with non­ cific technologies (e.g., biochemical technology, mi­ traditional technologies, along with their solutions. croelectronics processing, polymer processing). A sec- The problems are intended for use as examples in Phillip Savage is an assistant professor of ChE at the lectures or as homework assignments. Another ex­ University of Michigan. He received his BS from Penn ample is a set of articles on microelectronics process­ State and his MChE and PhD degrees from the Uni­ ing that recently appeared in Chemical Engineering versity of Delaware. His research interests are in re­ 12 61 action pathways, kinetics, and mechanisms. Education. - This paper describes a set of educational materi­ als that we have developed which deal with chemical engineering applications in "emerging" technologies. These materials take the form of a textbook supple­ Steven Blaine received a BSChE from the University ment. Our goal was to develop materials for use in a of Florida in 1986 and a MSE in chemical engineering chemical reaction engineering course. Thus, we se­ from the University of Michigan in 1988. Currently, he is a candidate for the PhD in chemical engineering at lected examples from microelectronics processing and the University of Michigan © Copyright ChE Division, ASEE 1991 150 Chemical Engineering Education A barrier to weaving examples from new technologies into existing courses ... is that most chemical engineering textbooks, though good at presenting fundamental principles, generally do not provide examples and applications from non-traditional technologies. Thus, the instructor is forced to identify and develop such examples on his own. biochemical technology that illustrate key concepts Nauman gives a brief and largely qualitative discus­ in kinetics and reaction engineering. Here we will sion of reaction engineering issues in the fabrication describe the organization and content of our text­ of electronic devices. Fogler provides a few problems book supplement and show how it can be integrated dealing with chemical vapor deposition at the end of into an undergraduate reaction engineering course. his chapter on heterogeneous reactions, along with A copy of the supplement can be obtained by writing three problems (without solutions) concerning mi­ to the authors. croelectronics fabrication in an appendix. An encouraging trend, evident in the table, is MOTIVATION FOR DEVELOPING THE that the most recent books have the most material COURSEPACK relevant to biotechnology and microelectronics proc­ essing. This trend will certainly continue as new and We began developing the materials described in revised textbooks are published. Fogler's second edi­ this paper in the spring of 1988. At that time there were very few such educational materials available tion, for instance, has an expanded treatment of to the chemical engineering community even though these topics. it was quite clear that examples from microelectron­ Our desire to integrate examples from non­ ics processing (for instance) could easily be used to traditional technologies into the traditional chemi­ illustrate key reaction engineering principles. Un­ cal reaction engineering course and the omission of fortunately, existing textbooks provided very few ap­ such examples in most texts motivated our work in plications ofreaction engineering principles to prob­ developing a textbook supplement. This supplement lems encountered in microelectronics processing and took the form of a spiral-bound coursepack that the biotechnology. students could purchase for a nominal fee from a Table 1 lists several reaction engineering texts local copying center. and the number of pages each devotes to these two particular technologies. As can be seen, many of the OVERVIEW AND ORGANIZATION OF THE texts completely omit any reaction engineering ap­ COURSEPACK plications in these technologies. Hill and Fogler, however, include several pages on enzyme kinetics. The coursepack comprises two main sections. One Nauman likewise covers Michaelis-Menten kinetics, deals with microelectronics processing and the other and he also includes a few pages on fermentation. with biochemical technology. The microelectronics processing section contains three chapters, and the Reaction engineering applications in microelec­ topics covered are chemical vapor deposition, plasma tronics processing are much more scarce, however. etching, and the thermal oxidation of silicon. The biochemical technology section contains two chap­ TABLE 1 ters: one concerns fermentation and bioreactor de­ Textbooks and Non-Traditional Technologies sign and the second discusses catalysis by immobi­ lized enzymes. Pages Devoted to Author Biotechnology Microelectronics Each of the chapters comprises three sections: Introduction, Applications of Chemical Reaction Carberry (1976)171 0 0 Engineering, and Problems. The first section intro­ Hill (1977)181 7 0 duces one particular aspect of an emerging technol­ Holland and Anthony (1979)1•1 0 0 ogy and provides background material necessary for Butt (1980)1101 0 0 the subsequent sections. The second section illus­ Smith (1981)111 1 0 0 trates, via examples, how established reaction engi­ Fogler (1986)112 1 8 3 neering principles can be applied to this particular Nauman (1987)1131 11 3 aspect of the technology. Detailed derivations are Froment and Bischoff (1990)1141 0 0 often omitted, and the student is expected to refer to Summer 1991 151 the textbook for basic explanations of the principles. with heterogeneous reaction kinetics. In this section The final section provides several problems that al­ we use the standard Langmuir-Hinshelwood-Hougen­ low the students to use what they have learned in Watson formalism to derive a rate law for deposition the earlier sections. of polycrystalline silicon from silane. This example illustrates the application of elementary reactions We have designed this textbook supplement so (adsorption, desorption, surface reaction) and the that it can be easily integrated into a chemical reac­ concept of a rate-limiting step. tion engineering class. The coursepack is structured so that the chemical reaction engineering principles The third application in the CVD chapter in­ that are being employed are clearly evident within volves an analysis of reaction and diffusion in a the applications section of each chapter. Table 2 horizontal, multiple-wafer-in-tube, low-pressure CVD summarizes the general reaction engineering prin­ reactor. The reactor contains a large number of closely ciples emphasized in each chapter in the coursepack. spaced wafers upon which it is desired to deposit a thin, uniform film. The direction of flow of the gase­ Organizing the coursepack around reaction ous reactants is normal to the wafer surface so diffu­ engineering principles facilitates the integration of sion is the dominant mode of transport between the relevant examples from non-traditional technologies wafers. Mathematically, this problem is identical to into the traditional course. For example, the con­ that ofreaction and diffusion in a porous, cylindrical cepts involved in the design of an isothermal CSTR catalyst particle. Thus, the principles of coupled rate can be illustrated using a rate law for cell growth processes (i.e., diffusion and surface reaction) can be kinetics as well as one for a generic reaction such as applied