Gate oxide punching thru mechanism in plasma dry etching  

作　　者：ZHANG QingZhao XIE ChangQing LIU Ming LI Bing CHEN BaoQin ZHU XiaoLi 

机构地区：[1]Laboratory of Nanofabrication and Novel Device Integration,Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Science China(Technological Sciences)》2008年第11期1990-1994,共5页中国科学（技术科学英文版）

基　　金：the National High-Tech Research and Development Program of China ("863" Project) (Grant No. 2006AA843134);the National Basic Research Program of China ("973" Project) (Grant No. 2007CB935302)

摘　　要：The punching thru mechanism of gate oxide (thickness about 15A) was investi- gated. Because of the thin thickness of gate oxide, gate oxide punching thru may easily happen during the plasma process. It was found that what caused the punching thru was not only the selectivity of poly-silicon/oxide but also the pattern topography. We used the basic SRAM pattern to check this topography effect, and found that gate oxide located at the narrow spacing of two parallel serpentine lines was the most easily punched thru. What caused the topography effect was the starvation of oxygen in these places which were induced by the residue of poly-silicon and enhanced by electron shading effect. So, to solve the issue of gate oxide punching thru, firstly the selectivity should be enough, secondly we should pay attention to the etching pattern topography.The punching thru mechanism of gate oxide (thickness about 15A) was investigated. Because of the thin thickness of gate oxide, gate oxide punching thru may easily happen during the plasma process. It was found that what caused the punching thru was not only the selectivity of poly-silicon/oxide but also the pattern topography. We used the basic SRAM pattern to check this topography effect, and found that gate oxide located at the narrow spacing of two parallel serpentine lines was the most easily punched thru. What caused the topography effect was the starvation of oxygen in these places which were induced by the residue of poly-silicon and enhanced by electron shading effect. So, to solve the issue of gate oxide punching thru, firstly the selectivity should be enough, secondly we should pay attention to the etching pattern topography.

关 键 词：PLASMA ETCH PUNCH thru GATE OXIDE 

分 类 号：TG172[金属学及工艺—金属表面处理]