The invention relates to a method (3) of fabricating a mold (39, 39′) including the following steps: (a) depositing (9) an electrically conductive layer on the top (20) and bottom (22) of a wafer (21) made of silicon-based material; (b) securing (13) the wafer to a substrate (23) using an adhesive layer; (c) removing (15) one part (26) of the conductive layer from the top of the wafer (21); and (d) etching (17) the wafer as far as the bottom conductive layer (22) thereof in the shape (26) of the one part removed from the top conductive layer (22) to form at least one cavity (25) in the mold. The invention concerns the field of micromechanical parts, particularly, for timepiece movements.