Microelectromechanical mirror device with piezoelectric actuation having improved stress resistance

A process for manufacturing a microelectromechanical mirror device, comprising:

• forming a fixed structure defining a cavity in a die of semiconductor material;
• elastically suspending a tiltable structure above the cavity, the tiltable structure carrying a reflecting region and having a main extension in a horizontal plane;
• forming at least a first pair of driving arms in the die of semiconductor material, the first pair of driving arms carrying respective piezoelectric structures biased to generate a driving force such as to cause a rotation of the tiltable structure about a rotation axis parallel to a first horizontal axis of said horizontal plane;
• elastically coupling said tiltable structure to said fixed structure at said rotation axis using elastic suspension elements, the elastic suspension elements being rigid to movements out of the horizontal plane and compliant to torsion about said rotation axis;
• and
• magnetically coupling said first pair of driving arms to said tiltable structure so as to cause its rotation about the rotation axis by magnetic interaction, following biasing of the respective piezoelectric structures.

A microelectromechanical mirror device, comprising, in a die of semiconductor material:

• a fixed structure defining a cavity;
• a tiltable structure carrying a reflecting region, wherein said tiltable structure is elastically suspended above the cavity;
• at least a first pair of driving arms carrying respective piezoelectric structures configured to be biased to generate a driving force such as to cause a rotation of the tiltable structure about a rotation axis;
• and
• elastic suspension elements configured to elastically couple said tiltable structure to said fixed structure at said rotation axis;
• wherein driving arms of said first pair of driving arms are magnetically coupled to said tiltable structure.