In a method of forming a pattern and a method of forming a capacitor, an oxide layer pattern having an opening is formed on a substrate. A conductive layer is formed on the oxide layer pattern and the bottom and sidewalls of the opening. A buffer layer pattern is formed in the opening having the conductive layer, the buffer layer pattern including a siloxane polymer. The conductive layer on the oxide layer pattern is selectively removed using the buffer layer pattern as an etching mask. A conductive pattern having a cylindrical shape can be formed on the substrate. The method of forming a pattern may simplify manufacturing processes for a capacitor and a semiconductor device, and may improve their efficiencies.