化学机械抛光工艺中的硅片背压力控制及优化.pdf

Vol. 32,No. 12 JournalofSemiconductors December2011 Waferback pressurecontroland optimizationintheCMPprocess Men Yanwu(门延武) ,Zhang Hui(张辉),Zhou Kai(周凯),and YePeiqing(叶佩青) State Key Laboratory of Tribology,TsinghuaUniversity,Beijing 100084,China Abstract: Chemicalmechanicalpolishing(CMP)isthemosteffectivewaferglobalplanarizationtechnology.The CMP polishing head is one of the most important components, and zone back pressure control technology is used to design a new generation of polishing head. The quality of polishing not only depends on slurry, but also de- pends on the precise control of polishing pressures. During the CMP polishing process, the set pressure of each chamber is usually not the same and the presence of a flexible elastic diaphragm causes coupling effects. Because of the coupling effects, the identification of multi-chambers and pressure controls becomes complicated. To solve the coupling problem, this paper presents a new method of multi-chamber decoupled control, and then system identification and control parameter tuning are carried out based on the method. Finally, experiments of multi- chambers inflated at the same time are performed. The experimental results show that the presented decoupling controlmethodis feasible and correct. Keywords: CMP;zonepressure control technology; decoupling control DOI: 10.1088/1674-4926/32/12/126002 EEACC: 2502 1. Introduction Zone back pressure control technology is still a hot re- search issue. The technology involves dividing a w