Abstract: The invention concerns the field of micromechanical parts, in particular, for timepiece movements. The invention relates to a method of fabricating a mould that includes the following steps: (a) providing a substrate that has a top layer and a bottom layer made of electrically conductive, micromachinable material, and secured to each other by an electrically insulating, intermediate layer; (b) etching at least one pattern in the top layer as far as the intermediate layer to form at least one cavity in the mould; (c) coating the top part of the substrate with an electrically insulating coating; and (d) directionally etching the coating and the intermediate layer to limit the presence thereof exclusively at each vertical wall formed in the top layer.

Abstract: The invention relates to a timepiece movement (1) comprising a sprung (7) balance (5) resonator (3) mounted between a bar (2) and a bottom plate (4) wherein the balance (7) is formed from a ferromagnetic material. According to the invention, the timepiece movement includes a magnetic polarising device (15) for said balance spring for maintaining a predefined state of polarisation in the balance spring (7) and including permanent magnetising means which forms a magnetic field in the plane of the balance spring so as to totally or almost totally magnetically saturate the balance spring (7) in the absence of an external magnetic field. The invention concerns the field of timepieces.

Abstract: Thermal treatment method for a micromechanical horological component derived from the LIGA method and exhibiting very low thermal inertia, said method including the step which consists in locally heating one area of the micromechanical horological component to increase hardness by local phase modification, the component being heated for a sufficiently short time that only the locally heated area is affected by the thermal treatment, the phase of the untreated portions of the component remaining unchanged.