AVS 52nd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP6
Chemical Mechanical Polishing Characteristics of BTO Thin Films by BaTiO@sub 3@ Abrasive Slurry for High-Density DRAM Application

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Electronic Materials and Processing Poster Session
Presenter: P.-J. Ko, Chosun University, Korea
Authors: P.-J. Ko, Chosun University, Korea
N.-H. Kim, Chosun University, Korea
J. Park, Chosun University, Korea
Y.-J. Seo, Daebul University, Korea
W.-S. Lee, Chosun University, Korea
Correspondent: Click to Email
BaTiO@sub 3@ (BTO) high dielectric thin films have received much attention as one of the new dielectric materials for high density dynamic random access memories (DRAMs) because of their high relative dielectric constant and small variation in dielectric properties with frequency. It is well known that BTO films are difficult to be etched by wet etching, but high etch rate with good selectivity to pattern mask was required. Plasma etching provided the high etch rate with good selectivity, however, the problem of sidewall angle still remained to be solved. In this study, we examined the characteristics of submicron capacitors fabricated by chemical mechanical polishing (CMP) process with the vertical sidewall instead of plasma etching. The sputtered BTO thin films on the stopper layer were polished by CMP with commercial alumina (Al@sub 2@O@sub 3@) slurry and self-developed BTO (BaTiO@sub 3@) abrasive slurry. The polishing results of BTO thin films using the harder alumina slurry represented the high removal rate, while the polishing results using the softer BTO slurry shows the relatively low removal rate with insufficient within-wafer non-uniformity (WIWNU%). The polishing mechanism of BTO thin films by two kinds of slurry was investigated by the surface analysis by X-ray photoelectron spectroscopy (XPS) with the surface morphology by atomic force microscopy (AFM). The surface roughness and planarity were also strongly depended on the self-developed BTO slurry. The vertical sidewall of BTO patterns was successfully accomplished by the damascene process of BTO thin film. Acknowledgement: This work was supported by a Korea Research Foundation grant (KRF-2004-005-D00007).