MEMS structure
A MEMS structure is provided. The MEMS structure includes a substrate having an opening portion and a backplate disposed on one side of the substrate and having acoustic holes. The MEMS structure also includes a diaphragm disposed between the substrate and the backplate and extending across the opening portion of the substrate. The diaphragm includes ventilation holes, and an air gap is formed between the diaphragm and the backplate. The MEMS structure further includes a coverage structure disposed on the sidewall of at least one ventilation hole.
1 . A micro-electro-mechanical system structure, comprising:
a substrate having an opening portion;
a backplate disposed on one side of the substrate and having acoustic holes;
a diaphragm disposed between the substrate and the backplate, extending across the opening portion of the substrate, and comprising a plurality of ventilation holes, wherein an air gap is formed between the diaphragm and the backplate; and
a plurality of coverage structures disposed on sidewalls of the plurality of ventilation holes, wherein the plurality of coverage structures is provided in a layer different from the diaphragm, wherein the plurality of coverage structures partially cover respective sidewalls of the plurality of ventilation holes such that portions of respective sidewalls of the diaphragm remain exposed, and in a vertical direction pointing from the substrate to the backplate, a top-most surface of the coverage structure is lower than a top surface of the diaphragm.
2 . The micro-electro-mechanical system structure as claimed in claim 1 , wherein each of the plurality of coverage structures forms a slit in the plurality of ventilation holes.
3 . The micro-electro-mechanical system structure as claimed in claim 2 , wherein a width of the slit is smaller than 0.4 μm.
4 . The micro-electro-mechanical system structure as claimed in claim 1 ,
wherein from a top view of the diaphragm, the plurality of ventilation holes are arranged in a plurality of ring shapes and surround the center of the diaphragm.
5 . The micro-electro-mechanical system structure as claimed in claim 4 ,
wherein the plurality of ventilation holes are divided into first ventilation holes and second ventilation holes arranged in a concentric manner.
6 . The micro-electro-mechanical system structure as claimed in claim 5 , wherein the first ventilation holes and the second ventilation holes are staggered relative to the center of the diaphragm.
7 . The micro-electro-mechanical system structure as claimed in claim 5 , wherein the first ventilation holes are disposed between the center of the diaphragm and the second ventilation holes in a radial direction of the diaphragm.
8 . The micro-electro-mechanical system structure as claimed in claim 7 , wherein the number of first ventilation holes is different from the number of second ventilation holes.
9 . The micro-electro-mechanical system structure as claimed in claim 7 , wherein each of first ventilation holes has a different size from each of second ventilation holes.
10 . The micro-electro-mechanical system structure as claimed in claim 7 ,
wherein the plurality of ventilation holes are further divided into third ventilation holes, and the second ventilation holes are disposed between the first ventilation holes and the third ventilation holes in the radial direction of the diaphragm.
11 . The micro-electro-mechanical system structure as claimed in claim 4 ,
wherein the plurality of ventilation holes are C-shaped, stripe-shaped, or curved.
12 . The micro-electro-mechanical system structure as claimed in claim 1 ,
wherein a width of each of the plurality of coverage structures is less than half of a thickness of the diaphragm.
13 . The micro-electro-mechanical system structure as claimed in claim 4 ,
wherein the plurality of ventilation holes are arranged adjacent to the center of the diaphragm or on a periphery of the diaphragm.
14 . The micro-electro-mechanical system structure as claimed in claim 1 ,
wherein each of the plurality of coverage structure covers a portion of the respective sidewall of the plurality of ventilation holes, and exposes another portion of the respective sidewall of the plurality of ventilation holes.
15 . The micro-electro-mechanical system structure as claimed in claim 1 , further comprising:
a pillar disposed between the backplate and the diaphragm.
16 . The micro-electro-mechanical system structure as claimed in claim 15 , wherein the pillar is disposed on a center of the diaphragm.
17 . The micro-electro-mechanical system structure as claimed in claim 15 , wherein the pillar and the diaphragm are separable.
18 . The micro-electro-mechanical system structure as claimed in claim 1 ,
wherein the plurality of coverage structures is made of a different material than the diaphragm.