We propose here a novel and stable method for fabricating spherical micromirror by bonding a flat freestanding single-crystal-silicon (SCS) membrane with a fulcrum on a glass substrate. Smooth convex spherical surface is achieved inside the fulcrum by the bending moment generated in the circumference of the SCS membrane. The surface profiles fit well with parabolic curves within 36nm RMS error indicating a good optical performance. By modifying the diameter of the fulcrum, we also demonstrate that it is possible to fabricate micromirrors with a wide range of focal length (0.4mm-1.6mm). The fabricated micromirrors are also used as the mold for replication of micro polymeric lenses. The surface profiles of the micromirrors are transferred to the polymeric replica with a high accuracy.