Slotted diaphragm semiconductor device

Claim 2

An integrated semiconductor device, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; and diaphragm means comprising the layer of thin film material and further comprising a static electric element and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extends only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots.

Claim 3

The apparatus of claim 1 wherein the static electric element comprises a permalloy element.

Claim 4

The apparatus of claim 2 wherein the permalloy element has a thickness in the range of approximately 800 angstroms to approximately 1,600 angstroms.

Claim 5

The apparatus of claim 1 wherein the layer of thin film material comprises a dielectric material.

Claim 6

The apparatus of claim 4 wherein the dielectric material comprises silicon nitride.

Claim 7

The apparatus of claim 4 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 8

An integrated semiconductor device, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; and diaphragm means comprising the layer of thin film material and further comprising a thermal-to-electric transducing element and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extend only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots.

Claim 9

An integrated semiconductor device, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; and diaphragm means comprising the layer of thin film material and further comprising a thermal-to-electric transducing element and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extend only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots.

Claim 10

The apparatus of claim 7 wherein the thermal-to-electrical transducing element comprises a permalloy element.

Claim 11

The apparatus of claim 8 wherein the permalloy element has a thickness in the range of approximately 800 angstroms to approximately 1,600 angstroms.

Claim 12

The apparatus of claim 7 wherein the layer of thin film material comprises a dielectric material.

Claim 13

The apparatus of claim 10 wherein the dielectric material comprises silicon nitride.

Claim 14

The apparatus of claim 10 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 15

An integrated semiconductor device, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; and diaphragm means comprising the layer of thin film material and further comprising an electric-to-thermal element and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extends only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots.

Claim 16

An integrated semiconductor device, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; and diaphragm means comprising the layer of thin film material and further comprising an electric-to-thermal element and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extends only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots.

Claim 17

The apparatus of claim 13 wherein the electric-to-thermal element comprises a permalloy element.

Claim 18

The apparatus of claim 14 wherein the permalloy element has a thickness in the range of approximately 800 angstroms to approximately 1,600 angstroms.

Claim 19

The apparatus of claim 13 wherein the layer of thin film material comprises a dielectric material.

Claim 20

The apparatus of claim 16 wherein the dielectric material comprises silicon nitride.

Claim 21

The apparatus of claim 16 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 22

A flow sensor, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; diaphragm means comprising the layer of thin film material and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extend only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots; a thin film heater supported over the depression by the diaphragm, approximately half of the heater being located on each side of the line oriented at substantially 45 degrees to the [110] direction; and a pair of thin film heat sensors supported by the diaphragm, the thin film heat sensors being disposed on opposite sides of the heater.

Claim 23

A flow sensor, comprising: a semiconductor body having a depression formed into a first surface of the body, the semiconductor body comprising (100) silicon and having a (100) plane and a [110] direction, the first surface of the semiconductor body being substantially parallel to the (100) plane; a layer of thin film material covering at least a portion of the first surface; diaphragm means comprising the layer of thin film material and forming a slotted diaphragm substantially covering the depression, the depression being bounded at the first surface by a substantially square configuration comprising four substantially perpendicular boundary edges, each of the four substantially perpendicular boundary edges being substantially in line with or substantially perpendicular to the [110] direction, the slotted diaphragm comprising slot means comprising first and second slots located on a line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots comprising a first end located at a maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, each of the first and second slots having a second end located so that each of the first and second slots extend only a portion of the distance across the maximum width of the depression as measured along the line oriented at substantially 45 degrees to the [110] direction, the slot means further comprising third, fourth, fifth and sixth slots oriented substantially in line with or substantially perpendicular to the [110] direction, there being one of the third, fourth, fifth and sixth slots located at the substantial center of each of the four boundary edges, each of the third, fourth, fifth and sixth slots having a length sufficient to permit undercutting of the diaphragm when an anisotropic etch is placed on each of the six slots; a thin film heater supported over the depression by the diaphragm, approximately half of the heater being located on each side of the line oriented at substantially 45 degrees to the [110] direction; and a pair of thin film heat sensors supported by the diaphragm, the thin film heat sensors being disposed on opposite sides of the heater.

Claim 24

The apparatus of claim 19 wherein the heater is operated at a temperature elevated above ambient, thus creating a no-flow temperature gradient in the air above and adjacent to the heater, the temperature within the no-flow gradient making a transition between the elevated temperature and substantially ambient temperature, the sensors being located sufficiently close to the heater to be located substantially within the no-flow temperature gradient.

Claim 25

The apparatus of claim 19 wherein the thin film heater and sensors each comprise a permalloy element.

Claim 26

The apparatus of claim 21 wherein each permalloy element has a resistance in the range of approximately 200 ohms to approximately 2000 ohms at approximately 25 degrees Centigrade.

Claim 27

The apparatus of claim 19 wherein the layer of thin film material comprises a dielectric material.

Claim 28

The apparatus of claim 23 wherein the dielectric material comprises silicon nitride.

Claim 29

The apparatus of claim 23 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 30

The apparatus of claim 19 wherein the sensors are located from the heater at a preferred distance which, when contrasted to an alternate distance, provides a substantially greater change in the heat being delivered to the sensors for a given change in flow rate.

Claim 31

The apparatus of claim 26 wherein the heater is operated at a temperature elevated above ambient, thus creating a no-flow temperature gradient in the air above and adjacent to the heater, the temperature within the no-flow gradient making a transition between the elevated temperature and substantially ambient temperature, the sensors being located sufficiently close to the heater to be located substantially within the no-flow temperature gradient.

Claim 32

The apparatus of claim 26 wherein the thin film heater and sensors each comprise a permalloy element.

Claim 33

The apparatus of claim 28 wherein each permalloy element has a resistance in the range of approximately 200 ohms to approximately 2000 ohms at approximately 25 degrees Centigrade.

Claim 34

The apparatus of claim 26 wherein the layer of thin film material comprises a dielectric material.

Claim 35

The apparatus of claim 30 wherein the dielectric material comprises silicon nitride.

Claim 36

The apparatus of claim 30 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 37

The apparatus of claim 19 wherein the proximal edges of the sensors are located from the near edges of the heater at a distance within the range of approximately 5 microns to approximately 25 microns.

Claim 38

The apparatus of claim 33 wherein the heater is operated at a temperature elevated above ambient, thus creating a no-flow temperature gradient in the air above and adjacent to the heater, the temperature within the no-flow gradient making a transition between the elevated temperature and substantially ambient temperature, the sensors being located sufficiently close to the heater to be located substantially within the no-flow temperature gradient.

Claim 39

The apparatus of claim 33 wherein the thin film heater and sensors each comprise a permalloy element.

Claim 40

The apparatus of claim 35 wherein each permalloy element has a resistance in the range of approximately 200 ohms to approximately 2000 ohms at approximately 25 degrees Centigrade.

Claim 41

The apparatus of claim 33 wherein the layer of thin film material comprises a dielectric material.

Claim 42

The apparatus of claim 37 wherein the dielectric material comprises silicon nitride.

Claim 43

The apparatus of claim 37 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 44

The apparatus of claim 19 wherein the heater and each sensor comprise a resistive element having a pattern of resistive material formed in lines having a line width, the lines being separated by substantially a line width, the sensors being separated from the heater by a distance in the range of approximately one line width to approximately five line widths.

Claim 45

The apparatus of claim 40 wherein the heater is operated at a temperature elevated above ambient, thus creating a no-flow temperature gradient in the air above and adjacent to the heater, the temperature within the no-flow gradient making a transition between the elevated temperature and substantially ambient temperature, the sensors being located sufficiently close to the heater to be located substantially within the no-flow temperature gradient.

Claim 46

The apparatus of claim 40 wherein the thin film heater and sensors each comprise a permalloy element.

Claim 47

The apparatus of claim 42 wherein each permalloy element has a resistance in the range of approximately 200 ohms to approximately 2000 ohms at approximately 25 degrees Centigrade.

Claim 48

The apparatus of claim 40 wherein the layer of thin film material comprises a dielectric material.

Claim 49

The apparatus of claim 44 wherein the dielectric material comprises silicon nitride.

Claim 50

The apparatus of claim 44 wherein the dielectric material has a thickness in the range of approximately 0.8 micron to approximately 1.2 microns.

Claim 53

The apparatus of claim 47 wherein the layer of thin film material comprises a dielectric material.

Claim 54

The apparatus of claim 48 wherein the dielectric material comprises silicon nitride.