| CPC H04R 19/04 (2013.01) [B81B 3/001 (2013.01); B81B 3/0072 (2013.01); B81C 1/00666 (2013.01); H04R 7/04 (2013.01); H04R 31/003 (2013.01); B81B 2201/0257 (2013.01); B81B 2203/0127 (2013.01); B81C 2201/0109 (2013.01); H04R 2201/003 (2013.01)] | 18 Claims |
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1. A micro-electromechanical systems (MEMS) element, comprising:
a substrate with an opening;
a vibrating membrane formed on the substrate through an insulating film, wherein slits are intermittently formed in a peripheral portion of the vibrating membrane along an edge thereof; and
a backplate that is fixedly formed on a spacer formed on a peripheral portion of the substrate and has a plurality of acoustic holes in a central portion thereof,
wherein the backplate has an etching hole at a position on an outer peripheral portion than the plurality of acoustic holes and closer to an edge side than an outermost peripheral end of the slits of the vibrating membrane in planar view, wherein the slits of the vibrating membrane are formed to be positioned above a portion of the substrate where the opening is not formed, wherein the edge of the vibrating membrane and the insulating film under the vibrating membrane are spaced apart from a bottom end of the spacer, and wherein a spacer side end of the insulating film under the vibrating membrane is positioned closer to the slits than the edge of the vibrating membrane and, a slit side end of the insulating film under the vibrating membrane is positioned closer to the spacer than the slits of the vibrating membrane.
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17. A method of manufacturing a MEMS element, the method comprising the steps of:
forming an insulating film on a substrate;
forming a conductive film on the insulating film, patterning a peripheral edge thereof, as well as forming a slit in a peripheral portion of the conductive film to form a vibrating membrane;
forming a sacrificial layer on the vibrating membrane;
forming a backplate film including a fixed electrode on the sacrificial layer;
forming a backplate which provided with a plurality of acoustic holes and an etching hole around the periphery of the plurality of acoustic holes in the backplate film;
forming an opening in the substrate at a position below a central portion of the vibrating membrane; and
removing the insulating film under the vibrating membrane so as to leave only a portion of the insulating film between an outermost periphery of the slit and an edge of the vibrating membrane, wherein the substrate is immersed in an etchant, thereby a portion of the insulating film is removed from the outermost peripheral side of the slit of the vibrating membrane and from the edge side of the vibrating membrane, while leaving a peripheral portion of the sacrificial layer as a spacer, and,
characterized in that the etching hole is formed closer to the peripheral portion side of the backplate than the outermost periphery of the slit of the vibrating membrane in planar view, and that the insulating film remaining under the vibrating membrane is made to remain in a ring shape that holds the vibrating membrane, by adjusting at least one of a position of the etching hole, a size of the etching hole, an etching time, and a concentration of the etchant.
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