The usage of barium strontium titanate (BST) capacitor have recently been considered in the fabrication of dynamic random access memory (DRAM) device. In this study, in order to avoid the difficulties of high aspect ratio etching of bottom electrode in the conventional stack-type capacitor structure, we suggest to introduce a. concave-type capacitor structure. The fabrication procedure of the two kinds of the concave capacitor cells, Pt/BST/Pt and Ru/BST/Ru are explained. We have studied on the metal electrode etching in the concave structure and have discussed the patterning issues in fabricating the capacitor structures.