Rapid thermal processing system

F. Roozeboom and N. Parekh, Rapid Thermal Processing Systems A Review with Emphasis on Temperature Control, / Vac. Sci. Technol. B., 8, pp. 1249-1259,1990. 

A rapid thermal processing system for microelectronics manufacturing uses three concentric lamp heater ar-rays to keep the wafer temperature uniform. The gain matrix for the system is... 

Water-soluble peroxide salts, such as ammonium or sodium persulfate, are the usual initiators. The initiating species is the sulfate radical anion generated from either the thermal or redox cleavage of the persulfate anion. The thermal dissociation of the persulfate anion, which is a first-order process at constant temperature (106), can be greatly accelerated by the addition of certain reducing agents or small amounts of polyvalent metal salts, or both (87). By using redox initiator systems, rapid polymerizations are possible at much lower temperatures (25—60°C) than are practical with a thermally initiated system (75—90°C). 

Heat evolution during immersion processes involving surface rehydration has been found to occur over a 20- to 40-minute interval, so that high precision methods are required if immersion heats include a contribution due to rehydration. The immersion heat determinations were carried out in a microcalorimeter having a temperature sensitivity of 5 X 10 6° C., rapid thermal response, and carefully determined heat transfer characteristics. The calorimetric system has a demonstrated capability of handling heat input rates as low as 0.005 joule per second (15). Samples for immersion were contained in very thin-walled bulbs holding... 

The PassPort system from Altea Therapeutics uses a thermal process to create an array of macropores across the stratum corneum. The device consists of a planar array system of small metallic filaments that rapidly converts electrical energy to thermal energy. The heat ablates the stratum corneum for a few milliseconds at a time and porates only the stratum corneum. After skin poration with this process, drug absorption occurs from a drug reservoir on the porated site. Hydromorphone and insulin delivery with this method is currently under human clinical testing. 

Whenever possible, more rapid turnaround time, the absence of load locks, the reduced maintenance cost associated with the avoidance of vacuum systems, and the ease of incorporation into continuous processing systems, all combine to make atmospheric pressure chemical vapor deposition an attractive technique. In general, removal of reaction co-products is accomplished by utilization of a large excess of carrier gas (typically argon or nitrogen). Additionally, it may be noted that the thermal oxidation... 

Due to the rapid changing technology in microcomputers and microprocessors, data and control systems have evolved rapidly a life time of 3-4 years is about the maximum for such a system. Thus, only the most current computer system will be described here for a particular type of thermal analysis system. No attempt will be made to give details on the software programs in use these can be obtained from the commercial vendor of the system, if desired. Almost all the commercially available thermal analysis instrumentation employs a microprocessor for operating system control or a microcomputer for data processing. Either a proprietary or a commercially available microcomputer is employed to process the experimental data into conventional thermal analysis plots or to perform more sophisticated kinetics or purity determination calculations. 

Due to smaller sample volumes and larger surface-to-volume ratios, the thermal control of microfluidic systems shows many advantages such as small amount of energy, simpler control system, and shorter control time. Precise control and rapid thermal control are also required in certain processes such as the polymerase chain reaction (PCR). 

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