AVS 49th International Symposium
    Plasma Science Wednesday Sessions
       Session PS+TF-WeP

Paper PS+TF-WeP24
Impact of Pattern Density on Characterization of Critical Dimension

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Plasma Etching & Deposition
Presenter: X. Xu, LSI Logic Corporation
Authors: X. Xu, LSI Logic Corporation
E. Croffie, LSI Logic Corporation
M. Garza, LSI Logic Corporation
Correspondent: Click to Email
The plasma etch of polysilicon is the most critical step in the fabrication of integrated circuits with submicron features since the critical dimension of polysilicon, which is typically used as gates, affects the speed performance of microelectronics devices. The characterization of polysilicon plasma etch can be varied by a global pattern density (called the loading effect) and a local pattern density (called the microloading effect). The etch variations, caused by the pattern density, depend on the specific plasma sources and tool configuration. In this work, silicon wafers patterned with photo resist on a stack of N-doped polysilicon and silicon dioxide have been etched on Lam 9400 DFM etching system in order to investigate the effects of pattern density on critical dimension (CD) and CD bias. The global density is obtained by varied dummy sizes and densities. The local effect is obtained by a large area with a certain polysilicon density and narrow isolated and dense lines at different distances from the large area. It has been found that the impact of global and local polysilicon densities with our new recipe on the tool is small compared to our old technology. In addition, the corresponding plasma chemistries have been studied by the Hybrid Plasma Equipment Model (HPEM).