Method of processing a wafer for manufacturing an oscillating structure such as a micro-mirror

A method of processing a wafer having a first side and a second side opposite to one another to manufacture an oscillating structure, comprising:

• a) forming first and second elastic torsional elements which are constrained to respective portions of a fixed supporting body and define an axis of rotation;
• b) forming a mobile element interposed between, and connected to, said first and second elastic torsional element;
• c) processing the first side of said wafer at the mobile element to form a mechanical reinforcement structure for the mobile element, by:
• c1) growing a reinforcement layer on the first side of the wafer;
• and
• c2) patterning said reinforcement layer by removing selective portions of the reinforcement layer to produce an annular reinforcement structure supporting the mobile element about a periphery thereof;
• and
• d) processing the second side of said wafer, including carrying out, at the second side of the wafer, at least one of:
• chemical etching, deposition of metal material, and deposition of piezoelectric material.

A method of processing a wafer having a first side and a second side opposite to one another to manufacture an oscillating structure, wherein said wafer is a silicon on insulator (SOI) wafer including an insulating layer interposed between a substrate and a structural layer, comprising:

• a) forming first and second elastic torsional elements which are constrained to respective portions of a fixed supporting body and define an axis of rotation;
• b) forming a mobile element interposed between, and connected to, said first and second elastic torsional elements, the mobile element being rotatable about the axis of rotation as a consequence of a torsion of the first and second elastic torsional elements;
• c) processing the first side of said wafer at the mobile element to form a mechanical reinforcement structure for the mobile element, by:
• forming an etch-stop layer on the structural layer,
• growing a reinforcement layer on the etch-stop layer, and
• masked etching of the reinforcement layer for removing selective portions thereof until the etch-stop layer is reached;
• and
• d) processing the second side of said wafer, including carrying out, at the second side of the wafer, at least one of:
• chemical etching, deposition of metal material, and deposition of piezoelectric material;
• wherein step d) is performed after performing step c).