Physical quantity sensor having multiple through holes

• US 20070120205A1
• Filed: 01/04/2007
• Published: 05/31/2007
• Est. Priority Date: 04/14/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Asai, Makoto, Yokoyama, Kenichi, Murata, Minoru
• Granted Patent: US 7,337,670 B2
• Time in Patent Office: Days
• US Class Current: 257/414
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A semiconductor physical quantity sensor includes: a substrate; a semiconductor layer supported on the substrate; a trench disposed in the semiconductor layer; and a movable portion disposed in the semiconductor layer and separated from the substrate by the trench. The movable portion includes a plurality of through-holes, each of which penetrates the semiconductor layer in a thickness direction. The movable portion is capable of displacing on the basis of a physical quantity applied to the movable portion so that the physical quantity is detected by a displacement of the movable portion. The movable portion has a junction disposed among the through-holes. The junction has a trifurcate shape.

Claims

1-4. -4. (canceled)

5. A semiconductor physical quantity sensor comprising:

a substrate;

a semiconductor layer supported on the substrate;

a plurality of trenches disposed in the semiconductor layer; and

a movable portion disposed in the semiconductor layer and separated from the substrate by the trenches, wherein

the movable portion includes a plurality of through-holes, each of which penetrates the semiconductor layer in a thickness direction,

the movable portion is capable of displacing on the basis of a physical quantity applied to the movable portion so that the physical quantity is detected by a displacement of the movable portion, and

one of the through-holes in the movable portion or one of the trenches disposed outer periphery of the movable portion has a width capable of performing a maximum etching rate of the semiconductor layer adjacent to the through-hole or the trench.

6. The sensor according to claim 5, wherein the through-hole or the trench having the width capable of performing the maximum etching rate is the through-hole in the movable portion.

7. The sensor according to claim 6, wherein

the trenches further includes a second width and a third width,

the trench having the second width and the trench having the third width are disposed outer periphery of the movable portion,

the second width is wider than the third width,

the through-hole having the width capable of performing the maximum etching rate in the movable portion is disposed neighboring to the trench having the second width.

8. The sensor according to claim 7, wherein the through-hole in the movable portion disposed neighboring to the trench having the third width is capable of performing a later etching rate of the semiconductor layer later than that of the through-hole in the movable portion disposed neighboring to the trench having the second width.

9. The sensor according to claim 5, wherein the etching rate of the semiconductor layer and the width of the through-hole or the trench have a relationship in such a manner that the maximum etching rate is obtained in a case where the width of the through-hole or the trench is around 7 μ

m.

10. The sensor according to claim 9, wherein the etching rate of the semiconductor layer and the width of the through-hole or the trench include further relationship in such a manner that the etching rate substantially becomes zero in a case where the width of the through-hole or the trench is equal to or larger than 10 μ

m.