TAKING THE TEMPERATURE OF RAPID THERMAL PROCESSING (RTP) SYSTEMS.How hot is it? Like weather watchers, semiconductor manufacturers want to know the answer to this question, especially for their rapid thermal processing Rapid Thermal Processing (or RTP) refers to a semiconductor manufacturing process which heats silicon wafers to high temperatures (up to 1200 C or greater) on a timescale of several seconds or less. systems. To reach the quality and device-performance requirements set for next-generation integrated circuits Integrated circuits Miniature electronic circuits produced within and upon a single semiconductor crystal, usually silicon. Integrated circuits range in complexity from simple logic circuits and amplifiers, about 1/20 in. (1. , chipmakers say they need a threefold improvement in their ability to measure and control temperature during single-wafer processing. A new, NIST-patented calibration wafer promises to deliver the desired level of accuracy. Just as significant, the wafer--instrumented with thin-film thermocouples--can link temperature measurements to the international temperature scale. This will make it easier to replicate processing conditions in different RTP (1) (Rapid Transport Protocol) The protocol used in IBM's High Performance Routing (HPR) system. (2) (Realtime Transport Protocol) An IP protocol that supports real time transmission of voice and video. chambers and at different facilities. A U.S. maker of RTP equipment and International SEMATECH SEMATECH Semiconductor Manufacturing Technology , the consortium of 13 chip makers, are evaluating the NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. test wafer in their own production and test equipment. During trial runs, chipmakers use test wafers to relate wafer temperatures to RTP chamber temperatures, which are recorded by a light pipe radiation thermometer, or LPRT LPRT Leading Producers' Round Table (insurance) LPRT Logistics Planning and Response Team LPRT Laboratory Project Review Team LPRT Local Timing Reference (ITU-T) . Inserted through the bottom of the chamber, the LPRT tracks the temperature during actual production. With current methods, LPRTs can be calibrated cal·i·brate tr.v. cal·i·brat·ed, cal·i·brat·ing, cal·i·brates 1. To check, adjust, or determine by comparison with a standard (the graduations of a quantitative measuring instrument): with an uncertainty of 5 [degrees]C to 6 [degrees]C The 1999 Technology Roadmap for Semiconductors set the goal of reducing measurement uncertainty to 2 [degrees]C. NIST's response to the challenge included substituting on-wafer, thin-film thermocouples for the wire ones now used to measure the temperature at different points on the surface. The thin-film approach eliminates the large junctions where pairs of thermocouple wires meet, avoiding the measurement-complicating heat transfer that occurs at these points. In addition, the NIST team developed methods for calibrating their thin-film thermocouples on the international temperature scale, achieving an uncertainty of about 0.3 [degrees]C. In turn, LPRTs now can be calibrated on the scale, to within 2[degrees]C. |
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