Patent ID: 9061895
Filing Date: 2015-06-23
Classification: B81B,B81C,G01P,H04R

Abstract:
1. A process for producing a micromechanical structure comprising a substrate and a stack of at least one first and one second active layer arranged on the substrate with the second active layer being above the first active layer, a mobile part formed in the stack and a fixed part relative to the substrate formed in the stack, the mobile part comprising portions of said at least two layers of said stack and the fixed part comprising portions of said at least two layers of said stack, the fixed part and the mobile part comprising opposite faces substantially parallel to a medium plane of the structure, a first face of the mobile part being under a first face of the fixed part such that the first face of the mobile part directly faces and is opposite the first face of the fixed part and a second face of the mobile part being above a second face of the fixed part such that the second face of the mobile part directly faces and is opposite the second face of the fixed part, and a free space is provided between at least one of the first faces of the mobile part and the fixed part or the second faces of the mobile part and the fixed part, said process comprising: from a stack of at least one first sacrificial layer and of the first active layer: a) structuring the first active layer so as to reveal the first sacrificial layer in at least two zones, b) forming a second sacrificial layer on the first active layer, the second sacrificial layer covering said zones revealing the first sacrificial layer and passing through the first active layer and being in contact with said first sacrificial layer in said zones, c) structuring said second sacrificial layer so as to obtain portions of a second sacrificial layer on the first active layer at the level of said zones where the second sacrificial layer passes through the first active layer, d) forming a second active layer on the portions of the second structured sacrificial layer and on the first active layer with which the second active layer is directly in contact, the material of the second sacrificial layer able to be etched selectively relative to those of the first and second active layers, e) structuring first and second active layers to present the portions of the second structured sacrificial layer and the first sacrificial layer, f) eliminating the portions of the second structured sacrificial layer between the opposite faces of the first and second active layers, and g) at least partially eliminating the first sacrificial layer releasing the mobile part, wherein step e) occurs after step a).