ABSTRACT
This chapter focuses on methods for detecting and controlling misprocessing, also termed systematic yield loss. The merging of both compensation and abnormality based methods is called Advanced Proess Control (APC) in the semiconductor industry. The supposition in APC is that there is expected non-random variation, expected random noise, and unexpected variation. While real-time compensation control techniques had existed for a few decades in the petrochemical, process, and aerospace industries, the development of control systems in the semiconducting industry initially was not based upon work in the industries. The most common of the abnormality-detection-based methods in the semiconductor industry is Statistical process control. As mentioned previously, Statistical Process Control, an abnormality detection and control method, has been practiced for many years in semiconductor manufacturing. The deadbanding prevents unnecessary control action similar to the statistical process control chart without suffering from unnecessary lag.
