Acceleration sensor

Abstract

An acceleration sensor, which enables rigidity to be ensured while forming multiple through-holes on a movable electrode, is provided. A silicon oxide layer (4) is formed on a silicon support layer (3). A Silicon on Insulator (SOI) substrate (2) having an active silicon layer (5) formed on the silicon oxide layer is provided. A movable electrode (11) constituted by a weight supported by elastic beams, and fixed electrodes (13xa, 13xb, 14ya, 14yb), which are fixed in a position facing the periphery of the movable electrode, are formed on the active silicon layer of the SOI substrate. Through-holes (16) that penetrate in the Z-axis direction are formed over the entire surface on the inside of an outer peripheral part where the elastic beams (12) of the movable electrode are linked.

Description

technical field [0001] The present invention relates to an acceleration sensor. The acceleration sensor comprises an SOI substrate formed by forming a silicon oxide layer on a silicon support layer, and forming an active silicon layer on the silicon oxide layer, and forming an active silicon layer on the SOI substrate. There are movable electrodes and fixed electrodes opposite to its periphery. Background technique [0002] As such an acceleration sensor, a capacitive semiconductor sensor has been proposed in which a fixed electrode and a movable electrode spaced from the inside and outside of the fixed electrode by a predetermined distance are arranged so that their detection surfaces face each other. , and form a through hole penetrating from the detection surface of the movable electrode and the fixed electrode to the surface opposite to the detection surface, thereby reducing the air damping generated between the movable electrode and the fixed electrode (for example, re...

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Problems solved by technology

[0008] However, in the conventional example described in the above-mentioned Patent Document 1, although air damping can be reduced by utilizing the through holes formed in the movable electrode and the fixed electrode, there is an unsolved problem as follows: Since only one Through holes, so the effect of reducing air damping is small, and when the movable electrode vibrates at a high frequency, a large air damping effect cannot be obtained

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