Functional device and manufacturing method thereof

Abstract

A functional device includes: a substrate; a functional structure formed on the substrate; a cavity in which the functional structure is disposed; and a cover which covers the cavity, wherein the cover includes a bumpy structure including rib shaped portions, or groove shaped portions, which cross a covering range covering at least the cavity.

1 . A functional device comprising:
 a substrate;   a functional structure formed on the substrate;   a cavity in which the functional structure is disposed; and   a cover which covers the cavity to enclose the cavity, such that the cavity is sealed, wherein the cover includes a bumpy structure including rib shaped portions, or groove shaped portions, which cross a covering range covering at least the cavity.   
     
     
         2 . The functional device according to  claim 1 , wherein the bumpy structure includes a plurality of the rib shaped portions or groove shaped portions collateral to each other. 
     
     
         3 . The functional device according to  claim 2 , wherein the bumpy structure is configured in a corrugated form in at least the covering range. 
     
     
         4 . The functional device according to  claim 1 , wherein the rib shaped portions are formed on an inner surface of the cover facing the cavity. 
     
     
         5 . The functional device according to  claim 1 , wherein the cavity is depressurized and sealed. 
     
     
         6 . The functional device according to  claim 1 , wherein the functional structure includes a movable portion on a cover side, and a range of the inner surface of the cover facing the cavity, which overlaps the movable portion in plan, is made a flat surface region which includes no slopes or steps provided by the rib shaped portions or the groove shaped portions. 
     
     
         7 . The functional device according to  claim 4 , wherein the functional structure includes a movable portion on a cover side, and the rib shaped portions are formed, avoiding the range overlapping the movable portion in plan, on the inner surface of the cover facing the cavity. 
     
     
         8 . The functional device according to  claim 1 , wherein the functional structure includes a movable portion on a cover side, and the bumpy structure is configured in such a way that the rib shaped portions or the groove shaped portions cross the range overlapping the movable portion in plan. 
     
     
         9 . The functional device according to  claim 1 , wherein the cover is a single, unitary piece. 
     
     
         10 . The functional device according to  claim 1 , wherein the covering range covers the entirety of the cavity. 
     
     
         11 . A method of manufacturing a functional device including a substrate, a functional structure formed on the substrate, a cavity in which the functional structure is disposed, and a cover which covers the cavity, the method comprising:
 forming the functional structure together with a sacrifice layer;   forming an insulating film, which includes a bumpy shape, including groove shaped portions or rib shaped portions, in at least one portion of a surface region, on the functional structure;   forming a first cover layer which, by being formed in the surface region, as well as having a bumpy structure, which includes rib shaped portions or groove shaped portions, reflecting the bumpy shape, has apertures;   removing the insulating film and sacrifice layer on the functional structure through the apertures of the first cover layer; and   forming a second cover layer closing the apertures of the first cover layer.   
     
     
         12 . The method according to  claim 11 , wherein in the covering step, by the second cover layer being formed in a depressurized space by a vapor growth method, the cavity is depressurized and sealed. 
     
     
         13 . The functional device manufacturing method according to  claim 11 , wherein forming the second cover layer comprises creating a single, unitary cover comprising the first and second cover layers. 
     
     
         14 . The method according to  claim 11 , wherein the bumpy structure crosses a covering range covering at least the cavity. 
     
     
         15 . The method according to  claim 11 , wherein the bumpy structure crosses a covering range covering at least the entirety of the cavity. 
     
     
         16 . A method of manufacturing a functional device including a substrate, a functional structure formed on the substrate, a cavity in which the functional structure is disposed, and a cover which covers the cavity, the method comprising:
 forming the functional structure together with a sacrifice layer;   forming an insulating film on the functional structure;   forming a first cover layer which includes an at least two layer laminate structure on the insulating film and, as well as having a bumpy structure including rib shaped portions, or groove shaped portions, which correspond to a formation range of at least one layer, has apertures;   removing the insulating film and sacrifice layer on the functional structure through the apertures of the first cover layer; and   forming a second cover layer closing the apertures of the first cover layer.   
     
     
         17 . The method according to  claim 16 , wherein in the covering step, by the second cover layer being formed in a depressurized space by a vapor growth method, the cavity is depressurized and sealed. 
     
     
         18 . The functional device manufacturing method according to  claim 16 , wherein forming the second cover layer comprises creating a single, unitary cover comprising the first and second cover layers. 
     
     
         19 . The method according to  claim 16 , wherein the bumpy structure crosses a covering range covering at least the cavity. 
     
     
         20 . The method according to  claim 16 , wherein the bumpy structure crosses a covering range covering at least the entirety of the cavity.