Advanced Process Control (APC) is now mainstream practice in the semiconductor manufacturing industry. Over the past decade and a half APC has evolved from a “good idea”, and “wouldn’t it be great” concept to mandatory manufacturing practice. APC developments have primarily dealt with two major thrusts, algorithms and infrastructure, and often the line between them has been blurred. The algorithms have evolved from very simple single variable solutions to sophisticated and cutting edge adaptive multivariable (input and output) solutions. Spending patterns in recent times have demanded that the economics of a comprehensive APC infrastructure be completely justified for any and all cost conscious manufacturers. There are studies suggesting integration costs as high as 60% of the total APC solution costs. Such cost prohibitive figures clearly diminish the return on APC investments. This has limited the acceptance and development of pure APC infrastructure solutions for many fabs. Modern APC solution architectures must satisfy the wide array of requirements from very manual R&D environments to very advanced and automated “lights out” manufacturing facilities.
A majority of commercially available control solutions and most in house developed solutions lack important attributes of scalability, flexibility, and adaptability and hence require significant resources for integration, deployment, and maintenance. Many APC improvement efforts have been abandoned and delayed due to legacy systems and inadequate architectural design. Recent advancements (Service Oriented Architectures) in the software industry have delivered ideal technologies for delivering scalable, flexible, and reliable solutions that can seamlessly integrate into any fabs’ existing system and business practices. In this publication we shall evaluate the various attributes of the architectures required by fabs and illustrate the benefits of a Service Oriented Architecture to satisfy these requirements. Blue Control Technologies has developed an advance service oriented architecture Run to Run Control System which addresses these requirements.
The need for process control in the semiconductor industry has been established and the benefits have been demonstrated. In the past, process control applications in the semiconductor manufacturing have relied on univariable control schemes. In the case of poly gate etch control methods have manipulated trim time or O2 flow to maintain a target poly gate FI CD target as the input DI CD varies. This study focuses on the impact of process control on secondary output goals and compares the effect of univariable control with that of multivariable control. There are two important conclusions for semiconductor manufacturers: (i) univariable control schemes sacrifice secondary control goals when trying to achieve the primary control goal and (ii) manufacturers must adopt multi-input multi-output control schemes to actively control both secondary process goals and primary control goals.