MEMS backplate, MEMS microphone comprising a MEMS backplate and method for manufacturing a MEMS microphone
View Patent ↗A MEMS backplate enables MEMS microphones with reduced parasitic capacitance. The MEMS backplate includes a central area and a perforation in the central area. A suspension area surrounds the central area at least partially. An aperture is disposed in the suspension area.
1. A MEMS microphone comprising:
a MEMS backplate, comprising:
a central area;
a perforation in the central area;
a suspension area that at least partially surrounds the central area, wherein the suspension area comprises aperture sections, and wherein the aperture sections are arranged above cavities;
a plurality of apertures concentrated in the aperture sections of the suspension area while other sections of the suspension area are substantially solid and maintain their mechanical stiffness;
a substrate,
an anchor element arranged between the substrate and the MEMS backplate so as to directly or indirectly mechanically connect the substrate to the MEMS backplate, wherein the anchor element comprises connection sections that are connected to the backplate's suspension area, and the cavities are arranged within the anchor element; and
a membrane arranged between the substrate and the anchor element.
2. The MEMS microphone of claim 1 , wherein the suspension area surrounds the central area completely.
3. The MEMS microphone of claim 1 , wherein the aperture sections are arranged at equal distances with respect to their neighboring aperture sections.
4. A method for manufacturing a MEMS microphone, the method comprising:
providing a substrate;
structuring a membrane on the substrate;
structuring an anchor element on the membrane;
structuring a backplate on the anchor element, thereby perforating a central area of the backplate and creating a plurality of apertures concentrated in aperture sections in a suspension area of the backplate while other sections of the suspension area are substantially solid, wherein the aperture sections are positioned over cavities arranged in the anchor element and the anchor element is positioned between the substrate and the backplate so as to directly or indirectly mechanically connect the substrate to the suspension area of the backplate; and
removing material of the anchor element in a region below the apertures.
5. The method of claim 4 , wherein material of the anchor element is removed using a VHF etching environment.