Facedown-type semiconductor pressure sensor with spacer

Claim 2

A facedown-type semiconductor pressure sensor comprising: (a) a sensing element having: (i) a semiconductor substrate having in one surface a recess for receiving an applied pressure to be measured, said recess being formed such that a thin portion is provided in said semiconductor substrate at a place corresponding to a bottom of said recess; (ii) layer means formed on the other surface of said semiconductor substrate, said thin portion and a portion of said layer means corresponding to said thin portion forming a diaphragm; (iii) a spacer having a hole therein formed on said layer means, said hole being substantially coaxial with said recess; (iv) piezoresistive means embedded in said diaphragm to produce an output in accordance with displacement of said diaphragm caused by application of the pressure to be measured; and (v) electrode means connected to said piezoresistive means for obtaining the output from said piezoresistive means, and (b) a pedestal to which said spacer is fixed such that a pressure chamber is defined by said hole and a surface of said pedestal, said pedestal supporting said layer means through said spacer.

Claim 3

A sensor as claimed in claim 1, wherein said spacer is provided by photolithography to have said hole therein.

Claim 4

A sensor as claimed in claim 1, wherein said layer means including an insulating layer made of silicon oxide, a polysilicon layer, and a protecting film made of silicon oxide.

Claim 5

A sensor as claimed in claim 3, wherein said piezoresistive means is embeded in said polysilicon layer.

Claim 6

A sensor as claimed in claim 1, wherein said pedestal is made of borosilicate glass.

Claim 7

A sensor as claimed in claim 1, wherein a surface of said pedestal defining said pressure chamber is flat, a thickness of said spacer being determined to be equal to a maximum value of said displacement.

Claim 8

A sensor as claimed in claim 1, wherein said spacer formed of polysilicon thin film.

Claim 9

A sensor as claimed in claim 1, wherein said spacer has a thickness of approximately 1.5-2.0 μm.

Claim 10

A sensor as claimed in claim 1, wherein said spacer has a through-hole, and said pedestal has a through-hole connected to said through-hole of said spacer and said electrode means comprising an output line which is provided through said through-holes of said spacer and said pedestal to externally output said output.

Claim 11

A sensor as claimed in claim 9, wherein said layer means further includes circuit means provided between said piezoresistive means and said electrode means.

Claim 12

A sensor as claimed in claim 10, wherein said spacer has a third through-hole for accommodating convexes of said circuit means.

Claim 13

A semiconductor pressure sensor comprising: (a) a glass pedestal having a flat surface; (b) spacer means formed on said flat surface; (c) a sensing element connected to said glass pedestal via said spacer means, said element having a flat surface, a Si diaphragm, a device determining a resistive value thereof in accordance with a pressure, and said device being provided at the side of said flat surface of said element; and (d) a sealed pressure chamber being defined by said glass pedestal, said spacer means, and said sensing element.

Claim 14

A semiconductor pressure sensor comprising: (a) a glass pedestal having a flat surface; (b) spacer means formed on said flat surface; (c) a sensing element connected to said glass pedestal via said spacer means, said element having a flat surface, a Si diaphragm, a device determining a resistive value thereof in accordance with a pressure, and said device being provided at the side of said flat surface of said element; and (d) a sealed pressure chamber being defined by said glass pedestal, said spacer means, and said sensing element.

Claim 15

A facedown-type semiconductor pressure sensor comprising: (a) a glass pedestal; (b) a sensing element for detecting a pressure, including: (i) an Si substrate having a diaphragm which is distorted by said pressure applied thereto; (ii) an insulating layer provided on said Si substrate; (iii) a polysilicon layer provided on said insulating layer; (iv) a piezoresistive region formed to said polysilicon layer; and (v) a protection film for protecting said piezoresistive region, said film being provided on said polysilicon layer and said piezoresistive region; (c) spacer means for connecting said glass pedestal and said sensing element; and (d) a reference pressure chamber defined by said glass pedestal, said sensing means, and said spacer, said spacer provided on said pedestal supporting said sensing element.

Claim 16

A facedown-type semiconductor pressure sensor comprising: (a) a glass pedestal; (b) a sensing element for detecting a pressure, including: (i) an Si substrate having a diaphragm which is distorted by said pressure applied thereto; (ii) an insulating layer provided on said Si substrate; (iii) a polysilicon layer provided on said insulating layer; (iv) a piezoresistive region formed to said polysilicon layer; and (v) a protection film for protecting said piezoresistive region, said film being provided on said polysilicon layer and said piezoresistive region; (c) spacer means for connecting said glass pedestal and said sensing element; and (d) a reference pressure chamber defined by said glass pedestal, said sensing means, and said spacer, said spacer provided on said pedestal supporting said sensing element.

Claim 17

A facedown-type semiconductor pressure sensor comprising: (a) a semiconductor substrate having a recess subjected to a pressure to be measured in one surface thereof, said recess being formed such that a thin portion is provided in said semiconductor substrate at a place corresponding to a bottom of said recess; (b) layer means formed on the other surface of said semiconductor substrate, said thin portion and a portion of said layer means corresponding to said thin portion forming a diaphragm; (c) a spacer made of a first material formed on said layer means having a hole, an inner side wall of said hole being positioned at a place corresponding to the bottom of said recess; (d) a pedestal, made of a second material which is different from said first material, to which said spacer is fixed such that a pressure chamber is defined by at least said inner side wall and a surface of said pedestal, said pedestal supporting said layer means through said spacer; (e) piezoresistive means positioned between said recess and said pressure chamber to produce an output in accordance with displacement of said diaphragm caused by said pressure; and (f) electrode means connected to said piezoresistive means for obtaining said output from said piezoresistive means.

Claim 18

A facedown-type semiconductor pressure sensor comprising: (a) a semiconductor substrate having a recess subjected to a pressure to be measured in one surface thereof, said recess being formed such that a thin portion is provided in said semiconductor substrate at a place corresponding to a bottom of said recess; (b) layer means formed on the other surface of said semiconductor substrate, said thin portion and a portion of said layer means corresponding to said thin portion forming a diaphragm; (c) a spacer made of a first material formed on said layer means having a hole, an inner side wall of said hole being positioned at a place corresponding to the bottom of said recess; (d) a pedestal, made of a second material which is different from said first material, to which said spacer is fixed such that a pressure chamber is defined by at least said inner side wall and a surface of said pedestal, said pedestal supporting said layer means through said spacer; (e) piezoresistive means positioned between said recess and said pressure chamber to produce an output in accordance with displacement of said diaphragm caused by said pressure; and (f) electrode means connected to said piezoresistive means for obtaining said output from said piezoresistive means.

Claim 19

A sensor as claimed in claim 14, wherein said spacer is provided by photolithography to have said hole therein.

Claim 20

A sensor as claimed in claim 14, wherein said layer means including an insulating layer made of silicon oxide, a polysilicon layer, and a protecting film made of silicon oxide.

Claim 21

A sensor as claimed in claim 16, wherein said piezoresistive means is embedded in said polysilicon layer.

Claim 22

A sensor as claimed in claim 14, wherein said second material is borosilicate glass.

Claim 23

A sensor as claimed in claim 14, wherein a surface of said pedestal defining said pressure chamber is flat, a thickness of said spacer being determined to be equal to a maximum value of said displacement.

Claim 24

A sensor as claimed in claim 14, wherein said first material is a polysilicon thin film.

Claim 25

A sensor as claimed in claim 14, wherein said spacer has a thickness of approximately 1.5-2.0 m.

Claim 26

A sensor as claimed in claim 14, wherein said spacer has a through-hole positioned in a portion of said spacer being different from said hole, and said pedestal has a through-hole connected to said through-hole of said spacer and said electrode means comprises an output line which is provided through said through-hole of said spacer and said pedestal to externally output said output.

Claim 27

A sensor as claimed in claim 22, wherein said layer means further includes circuit means provides between said piezoresistive means and said electrode means.

Claim 28

A sensor as claimed in claim 23, wherein said spacer has a second through-hole for accommodating convexes of said circuit means.

Claim 29

A sensor as claimed in claim 14, wherein said pressure chamber is sealed.

Claim 30

A sensor as claimed in claim 14, wherein said hole is a through-hole.

Claim 31

A sensor as claimed in claim 26, wherein said pressure chamber is defined by said inner side wall of said through-hole, said surface of said pedestal, and a surface of said layer means.

Claim 32

A sensor as claimed in claim 14, wherein said piezoresistive means embedded in said layer means.