The present application provides the block copolymers and their application. The block copolymer has an excellent self assembling property and phase separation and various required functions can be freely applied thereto as necessary.

A process for manufacturing a microelectromechanical mirror device includes, in a semiconductor wafer, defining a support frame, a plate connected to the support frame so as to be orientable around at least one rotation axis, and cantilever structures extending from the support frame and coupled to the plate so that bending of the cantilever structures causes rotations of the plate around the at least one rotation axis. The process further includes forming piezoelectric actuators on the cantilever structures, forming pads on the support frame, and forming spacer structures protruding from the support frame more than both the pads and the stacks of layers forming the piezoelectric actuators.