Nanocalorimetry using micromachined devices has the capability to provide quantitative data to support the development of advanced metal silicide metallizations for semiconductor devices. The nanocalorimeter developed in the Process Sensing Group can heat nanogram samples to 560 °C in as little as 20 ms. These specifications make the device potentially useful for developing data to analyze ultrarapid thermal anneal processes that are inaccessible to conventional calorimetry. To establish a method for performing quantitative measurements using these devices, a series of calibration measurements were taken. Calibrated structures make use of phase-change materials to enable the determination of temperature and enthalpy changes from collected signals. A measurement procedure was then developed for acquiring quantitative data, making use of a vacuum chamber, specified heating rates, and data analysis and modeling tools. A nickel/silicon reaction with stoichiometry of technical importance was characterized, comparing the effect of different heating rates, and thereby demonstrating the utility of the method for other stoichiometries and other materials combinations.
The global market for semiconductor chips is $270 billion. Growth in this industry is driven by the need to enhance performance by packing more transistors into the same chip area, with a relationship between feature size and time that approximately follows Moore’s Law. As the feature size shrinks below 45 nm, the limits in performance of conventional materials are being reached. The industry is moving towards a metal gate/high-k dielectric combination in which fully silicided (FUSI) metal gates are receiving a lot of attention for the metal layer. Advanced submicrometer CMOS technology requires the development of new materials, centered on the utilization of high dielectric constant materials for the gate oxide. Along with the new oxide materials, new gate metallizations are being used. Because of their desirable work function and thermal properties, metal silicides are receiving a lot of attention. An important example is the Ni-Si intermetallic system, which is made by thermally annealing separately deposited Ni and Si. The particular intermetallic phase or phases that form depend on the ratio of Ni to Si and on the annealing process. Further, the thermal annealing process must be compatible with other processes that are used in making the semiconductor devices on the wafer. This favors rapid and ultra-rapid processes. Conventional calorimetry has served as a key tool for the development of phase diagrams, but is limited to heating rates much slower than required for characterizing these fast annealing processes.
Lead Organizational Unit:mml
Dr. Richard Cavicchi
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