Estimation and Closed-Loop Control for Rapid Thermal Processing Systems

9312451 快速热处理（RTP）技术是近年来发展起来的一种有望突破半导体制造瓶颈的技术。 这种新技术涉及使用高功率卤钨灯将半导体晶片的温度迅速升高到所需的固化温度。 通过使用多变量反馈控制，可以将晶片温度保持在可接受的公差带内。 直到最近，执行所需温度测量的唯一准确方法是将热电偶嵌入晶片中。 然而，这种技术在生产中并不实用。 一个潜在的突破，在执行所需的测量是基于使用多波长红外成像高温计最近开发的NJIT的电子成像实验室与大卫Sarnoff研究中心。 该传感器原则上能够通过蓝宝石窗口以所需的精度测量晶片的温度。 由于需要估计不同波长下的发射率和温度，提取温度数据将需要复杂的数据处理。 扩展卡尔曼滤波（EKF）是首选算法。 然而，使用EKF算法会影响控制问题的制定方式。 特别是，它是必要的，以捕捉正确的温度依赖性估计的发射率使用的过程中的非线性动态模型。 因此，设计闭环控制器需要处理非线性控制和估计问题。 拟议的调查将解决这个问题和它提出的理论问题。 ***

9312451 Friedland A technique of rapid thermal processing (RTP) has recently been developed which promises to break a bottleneck in semiconductor manafacturing. This new technique involves the use of high power tungsten-halogen lamps to raise the temperature of a semiconductor wafer rapidly to the desired curing temperature. By use of multivariable feedback control it is possible to maintain the wafer temperature within an acceptable tolerance band. Until recently, the only accurate method of performing the required temperature mearsurments was to imbed thermocouples in the wafer. This technique, however, is not practical for use in production. A potential breakthrough in performing the required measurement is based on the use of a multi-wavelength infrared imaging pyrometer recently developed by NJIT's Electronic Imaging Laboratory in conjunction with the David Sarnoff Research Center. This sensor, in principle, is capable of measuring the temperature of the wafer through a sapphire window with the required accuracy. Extraction of temperature data will entail sophisticated data processing, owing to the requirement of estimating both emissivity and temperature at the different wavelengths. Extended Kalman filtering (EKF) is the preferred algorithm. Use of the EKF algorithm, however, impacts on how the control problem is formulated. In particular, it is necessary to use a nonlinear dynamic model of the process in order to capture the correct temperature dependence for estimation of emissivity. Hence, designing a closed loop controller necessitates dealing with a nonlinear control and estimation problem. The proposed investigation will address this problem and the theoretical issues it raises. ***