U.S. patent application number 13/401727 was filed with the patent office on 2013-08-22 for pressure sensor.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is Ryan Jones, Paul Rozgo, Richard Charles Sorenson. Invention is credited to Ryan Jones, Paul Rozgo, Richard Charles Sorenson.
Application Number | 20130214369 13/401727 |
Document ID | / |
Family ID | 48981643 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130214369 |
Kind Code |
A1 |
Jones; Ryan ; et
al. |
August 22, 2013 |
PRESSURE SENSOR
Abstract
The present disclosure relates to pressure sensor assemblies and
methods. The pressure sensor assembly may include a first
substrate, a second substrate and a sense die. The first substrate
may be connected to the second substrate, such that an aperture in
the first substrate is in fluid communication with an aperture in
the second substrate. The second substrate may be connected to the
sense die, such that the aperture in the second substrate is in
fluid communication with a sense diaphragm on the second substrate.
The pressure sensor assembly may include a media path that extends
through the aperture in the first substrate, through the aperture
in the second substrate, and to the sense die. In some cases, the
first substrate, the second substrate and the sense die may be
connected in a manner that does not include an adhesive.
Inventors: |
Jones; Ryan; (Dublin,
OH) ; Rozgo; Paul; (Dublin, OH) ; Sorenson;
Richard Charles; (Columbus, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jones; Ryan
Rozgo; Paul
Sorenson; Richard Charles |
Dublin
Dublin
Columbus |
OH
OH
OH |
US
US
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
48981643 |
Appl. No.: |
13/401727 |
Filed: |
February 21, 2012 |
Current U.S.
Class: |
257/419 ;
257/E21.499; 257/E29.324; 438/51 |
Current CPC
Class: |
H01L 2224/48137
20130101; G01L 19/147 20130101; H01L 2224/48091 20130101; G01L
19/0038 20130101; H01L 2224/48091 20130101; H01L 2924/00014
20130101 |
Class at
Publication: |
257/419 ; 438/51;
257/E29.324; 257/E21.499 |
International
Class: |
H01L 29/84 20060101
H01L029/84; H01L 21/50 20060101 H01L021/50 |
Claims
1. A sensor assembly, comprising: a metal substrate having a first
side and a second side, with an aperture extending between the
first side and the second side; a glass substrate having a first
side and a second side, with an aperture extending between the
first side and the second side; the first side of the metal
substrate is fused to the second side of the glass substrate along
a fusing surface to form a hermetic glass-to-metal seal, with the
aperture in the glass substrate in fluid communication with the
aperture in the metal substrate; a sense die having a first side
and a second side, the sense die defining a pressure sensitive
diaphragm that has one or more sense elements mounted adjacent to
the first side of the sense die; and the second side of the sense
die is bonded to the first side of the glass substrate with one of
an anodic bond and a frit bond, with the aperture in the glass
substrate in fluid communication with the diaphragm of the sense
die.
2. The sensor assembly of claim 1, wherein: the first side of the
metal substrate has a bottom surface, a top surface, and an inner
side surface extending from the bottom surface to the top surface,
where the fusing surface includes at least a portion of the bottom
surface and at least a portion of the inner side surface of the
metal substrate.
3. The sensor assembly of claim 2, further comprising: a printed
circuit board secured relative to the metal substrate; and wherein
one or more bond pads on the sense die are connected to one or more
bond pads on the printed circuit board.
4. The sensor assembly of claim 1, wherein the metal substrate is
at least partially formed of a nickel-cobalt ferrous alloy.
5. The sensor assembly of claim 1, wherein the hermetic
glass-to-metal seal is formed by heating the glass substrate until
the glass substrate wets, and is then fused to the metal substrate
upon cooling.
6. The sensor assembly of claim 1, further comprising: a metal port
bonded to the second side of the metal substrate, wherein a media
path extends through the metal port, through the aperture in the
metal substrate, through the aperture in the glass substrate, and
to the pressure sensitive diaphragm of the sense die.
7. The sensor assembly of claim 6, wherein the metal port is bonded
to the second side of the metal substrate via a weld
connection.
8. The sensor assembly of claim 6, wherein the metal port is bonded
to the second side of the metal substrate via a solder
connection.
9. A sensor apparatus, comprising: a first substrate having a first
side and a second side, with an aperture extending between the
first side and the second side; a second substrate having a first
side and a second side, with an aperture extending between the
first side and the second side; a hermetic substrate-to-substrate
fusion seal between the first side of the first substrate and the
second side of the second substrate along a fusing surface, with
the aperture in the second substrate in registration with the
aperture in the first substrate; a sense die having a first side
and a second side, the sense die having one or more sense elements;
and the second side of the sense die is joined to the first side of
the second substrate, with the aperture in the second substrate in
fluid communication with the sense die; and wherein a media path
extends through the aperture in the first substrate, through the
aperture in the second substrate and in direct contact with the
sense die.
10. The sensor apparatus of claim 9, wherein the second side of the
sense die is joined to the first side of the second substrate via a
frit bond.
11. The sensor apparatus of claim 9, wherein the second side of the
sense die is joined to the first side of the second substrate via
an anodic bond.
12. The sensor apparatus of claim 9, wherein: the first substrate
includes metal; the second substrate includes glass; and the sense
die includes silicon.
13. The sensor apparatus of claim 12, wherein thermal properties of
the first substrate, the second substrate, and the sense die result
in low stress transmission of thermally generated external forces
to the sense die.
14. A method of forming a sensor apparatus, comprising; fusing a
first side of a metal substrate to a second side of a glass
pedestal, wherein the metal substrate includes an aperture and the
glass pedestal includes an aperture, and wherein after the fusing
step, the aperture in the metal substrate is in fluid communication
with the aperture in the glass pedestal; bonding a silicon sense
die to a first side of the glass pedestal with one of an anodic
bond and a frit bond; and wherein the fusing step and the bonding
step result in a media path extending through the aperture in the
metal substrate, extending through the aperture in the glass
pedestal, and in direct contact with the silicon sense die.
15. The method of claim 14, wherein the fusing step comprises:
heating the glass pedestal until a portion of the second side of
the glass pedestal wets; contacting the portion of the wet second
side of the glass pedestal with the first side of the metal
substrate; and cooling the portion of the wet second side of the
glass pedestal that is in contact with the first side of the metal
substrate, resulting in a hermetic metal-to-glass seal between the
metal substrate and the glass pedestal.
16. The method of claim 14, wherein the bonding step comprises:
contacting the first side of the glass pedestal with the silicon
sense die; applying a voltage across the contacting first side of
the glass pedestal and the silicon sense die; and applying heat to
the contacting first side of the glass pedestal and the silicon
sense die.
17. The method of claim 14, wherein the bonding step comprises:
applying a glass frit paste between the first side of the glass
pedestal and the silicon sense die; heating one or more of the
glass pedestal, the glass frit paste, and the silicon sense die;
and cooling one or more of the glass pedestal, the glass frit
paste, and the silicon sense die.
18. The method of claim 14, further comprising: providing a printed
circuit board; and wire bonding one or more bond pads on the
silicon sense die to one or more bond pads on the printed circuit
board.
19. The method of claim 14, further comprising: bonding a metal
port to a second side of the metal substrate, wherein the media
path extends through the metal port, through the aperture in the
metal substrate, through the aperture in the glass pedestal, and to
the silicon sense die.
20. The method of claim 19, wherein the metal port is bonded to the
second side of the metal substrate via a weld connection.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to sensors, and
more particularly, to pressure sensors.
BACKGROUND
[0002] Pressure sensors often include a pressure sense element that
is configured to detect a pressure of a media to be sensed by
converting mechanical stress caused by the incoming pressure of the
media into an electrical output signal. Pressure measurements are
typically taken in the context of absolute, gauge, or differential
(or relative) pressure measurements. An absolute pressure sensor
represents a specific type of sensing device, which measures a
pressure relative to a vacuum (or near vacuum). A gauge sensor, on
the other hand, measures a pressure relative to atmospheric
pressure. A differential pressure sensor measures a pressure
difference between two inputs. Pressure sensors are used in a wide
variety of applications including, for example, commercial,
automotive, aerospace, industrial, and medical applications, among
other similar and dissimilar industries.
SUMMARY
[0003] This disclosure relates generally to sensors, and more
particularly, to sensors that are exposed to media during use.
Although sensor assemblies are known to exist, there is need for
improvement to such sensor assemblies.
[0004] Accordingly, in one illustrative embodiment, a pressure
sensor assembly may include a first substrate having an aperture, a
second substrate having an aperture, and a sense die having a sense
diaphragm. The first substrate may be connected to the second
substrate, such that the aperture in the first substrate is in
fluid communication and/or in registration with the aperture in the
second substrate. The second substrate may be connected to the
sense die, such that the aperture in the second substrate is in
fluid communication and/or in registration with the sense diaphragm
of the sense die. The connected pressure sensor assembly may
include a media path extending through the aperture in the first
substrate, through the aperture in the second substrate, and to and
in direct contact with the sense diaphragm of the sense die.
Although, the pressure sensor assembly may be made from any
suitable material or material combination, the first substrate may
include metal, the second substrate may include glass, and the
sense die may include silicon.
[0005] In some cases, the features of the pressure sensor may be
connected in any manner. For example, the first substrate may be
joined with the second substrate using a fusing technique to create
a hermetic substrate-to-substrate (e.g., metal-to-glass) seal, and
the second substrate may be joined with the sense die using an
anodic bonding technique or a frit bonding technique to create a
substrate-to-sense die (e.g., glass-to-silicon) seal.
[0006] In some cases, the pressure sensor assembly may include a
port (e.g., a metal port) with an aperture, a printed circuit
board, and/or a housing. The port may be connected to the first
substrate such that the aperture of the port is in fluid
communication and/or in registration with the aperture of the first
substrate, where any connection technique may be used to connect
the port to the first substrate. For example, the port may be
connected to the first substrate through a welding or soldering
technique. In some illustrative instances, the printed circuit
board of the pressure sensor assembly may be connected to the first
substrate, and may be in electrical communication with the sense
die. To protect the sense die and printed circuit board, and for
other purposes, the housing may be connected to the first
substrate, where the housing at least partially encloses the sense
die and the printed circuit board. In some cases, the housing may
include an external electrical connection that may be electrically
linked to the printed circuit board to provide electrical
communication from the sense die to a unit or device external to
the housing.
[0007] The preceding summary is provided to facilitate a general
understanding of some of the innovative features of the present
disclosure, and is not intended to be a full description. A full
appreciation of the disclosure can be gained by taking the entire
specification, claims, drawings, and abstract as a whole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The accompanying figures, in which like reference numerals
refer to identical or functionally-similar elements throughout the
separate views, and which are incorporated in and form a part of
the specification, further show several illustrative embodiments
and, together with the description, serve to explain the several
illustrative embodiments, wherein:
[0009] FIG. 1 is a schematic cross-sectional view of an
illustrative pressure sensor;
[0010] FIG. 2 is a schematic exploded cross-sectional view of the
illustrative pressure sensor of FIG. 1; and
[0011] FIG. 3 is a schematic cross-sectional view of an
illustrative pressure sensor assembly.
[0012] While the disclosure is amenable to various modifications
and alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in detail. It should
be understood, however, that the intention is not to limit aspects
of the disclosure to the particular illustrative embodiments
described herein. On the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the disclosure.
DESCRIPTION
[0013] The following description should be read with reference to
the drawings wherein like reference numerals indicate like elements
throughout the several views. The description and drawings, which
are not necessarily to scale, depict illustrative embodiments and
are not intended to limit the scope of the disclosure. The
illustrative embodiments depicted are intended only as
exemplary.
[0014] FIG. 1 is a schematic cross-sectional view of an
illustrative pressure sensor 10. The pressure sensor 10 may include
a sense die 12, a first substrate 30 having an aperture 31, and a
second substrate 20 having an aperture 21, where pressure sensor 10
may include a media path 18 extending at least from a second side
30b of first substrate 30 to a second side 12b of sense die 12 and
through the apertures 21, 31. As illustrated in FIG. 1, the second
side 12b of sense die 12 may be connected to a first side 20a of
second substrate 20, and a second side 20b of second substrate 20
may be connected to a first side 30a of first substrate 30. The
sense die 12, the second substrate 20 and the first substrate 30
may be connected and/or affixed to one another through one or more
various connection techniques including, but not limited to, anodic
bonding, frit bonding, fusing, welding, soldering, or any other
suitable bonding, connecting or sealing technique, as desired.
[0015] The pressure sensor 10 may be any type of pressure sensor.
In an illustrative embodiment, pressure sensor 10 may be a pressure
sensor such as an absolute pressure sensor, a gauge pressure
sensor, or other pressure sensor as desired. Example pressure
sensors may include, but are not limited to, those described in
U.S. Pat. Nos. 7,503,221; 7,493,822; 7,216,547; 7,082,835;
6,923,069; 6,877,380, and U.S. patent application publications:
2010/0180688; 2010/0064818; 2010/00184324; 2007/0095144; and
2003/0167851, all of which are hereby incorporated by
reference.
[0016] In some cases, the first substrate 30 may have a first side
30a and a second side 30b with the aperture 31 extending from the
first side 30a to the second side 30b. The first substrate 30 may
take on any shape and size and may be made of any desirable
material, such that its first side 30a is configured to be at least
partially affixed to the second substrate 20 and the aperture 31 of
the first substrate 30 is configured to be in fluid communication
and/or in registration with the aperture 21 of the second substrate
20.
[0017] In some instances, the first substrate 30 may be at least
partially made from a metal material (e.g., a metal material
including aluminum, stainless steel, a nickel-cobalt ferrous alloy
such as KOVAR.RTM., any other metal material, and/or any
combination of metal materials). In some cases, the first substrate
30 may be entirely made from the metal material, while in other
cases, the first substrate 30 may be coated with a metal material.
As mentioned, first substrate 30 may take on any shape and size.
For example, in some cases, the first side 30a of first substrate
30 may have a bottom surface 30a', a top surface 30a''', and an
inner side surface 30a'' extending from the bottom surface 30a' to
the top surface 30a''', as shown in FIGS. 1-3. Further, the first
substrate 30 may include a fusing surface for connection with the
second substrate 20, which in the illustrative embodiment, includes
at least a portion of the bottom surface 30a' and/or the inner side
surface 30a''.
[0018] In some illustrative instances, the first substrate 30 may
be layered (e.g., include two or more layers of material), but this
is not required. For example, the first substrate 30 may have two
or more layers which may be a metal material, where those metal
layers may be bonded directly to one another and/or may include one
or more intermediate layers that may or may not be of a metal
material. Where the first substrate 30 includes two or more metal
layers, a first metal layer may be configured to be connected to
the second substrate 20 and a second metal layer may be configured
to be connected to a metal port 70 or other port or substrate. The
first substrate 30 may include two or more layers for any purpose.
For example, the first substrate 30 may include two or more layers
in applications where a first metal layer may be affixed to the
second substrate 20, a second metal layer may be affixed to a metal
port 70, and the first and second metal layers may be connected to
one another either directly or through one or more intervening
layers.
[0019] Any intermediate layers of the first substrate 30 may be
made of a metal or any other suitable material. Illustratively, any
intermediate layer may be made from a material that is capable of
being connected or affixed to the metal layers without the use of
adhesive (e.g., where a connection is made through a weld or solder
connection), as media traveling through aperture 31 may be capable
of corroding adhesive materials and may undesirably weaken any
seals between layers of the first substrate 30. In addition, any
intermediate layer between the two or more metal layers may be made
of a material that is capable of being connected to the metal
layers of the first substrate 30 in a sealed (e.g., a hermetic
sealed) manner. Alternatively, or in addition, the various layers
of first substrate 30 (when more than one layer is present) may be
coated with a metal coating to facilitate bonding the first
substrate 30 to the second substrate 20 and a metal port 70 or the
like, and/or to help project the various layers of the first
substrate 30 from the media present in aperture 31.
[0020] In some cases, the second substrate 20 may have a first side
20a and a second side 20b with the aperture 21 extending from the
first side 20a to the second side 20b. The second substrate 20 may
take on any shape and size and may be made of any desirable
material, such that its first side 20a and second side 20b are
configured to be at least partially affixed to the sense die 12 and
the first substrate 30, respectively, and the aperture 21 of second
substrate 20 may be configured to be in fluid communication and/or
in registration with the sense diaphragm 14 of sense die 12 and the
aperture 31 of first substrate 30. In one example, the second
substrate 20 may be a glass pedestal at least partially made from a
glass material (e.g., borosilicate glass, such as PYREX.RTM.,
BOROFLOAT.RTM. 33, HOYA SD-2, and/or other borosilicate glass
materials, etc.). In some cases, the glass material(s) of second
substrate 20 may have thermal properties that are similar to the
thermal properties of a silicon material used for the sense die 12,
such that the connection of the sense die 12 with the second
substrate 20 creates a platform for the sense die 12 that creates a
low stress transmission to the sense diaphragm 14 from thermally
generated forces.
[0021] In some cases, metal material(s) of the first substrate 30,
the glass material(s) of second substrate 20, and the silicon
material(s) used for the sense die 12 may all have similar thermal
properties, such that the connection of the sense die 12 with the
second substrate 20 and the first substrate 30 may create a
platform having low stress transmission to the sense diaphragm
14.
[0022] In some illustrative instances, the second substrate 20 may
be layered (e.g., include two or more layers or sections of
material), but this is not required. For example, the second
substrate 20 may have two or more layers which may be a glass
material, where those glass layers may be bonded directly to one
another and/or may include one or more intermediate layers that may
or may not be of a glass material. Where the second substrate 20
includes two or more glass layers, a first glass layer may be
configured to be connected to the sense die 12 and a second glass
layer may be configured to be connected to the first substrate 30,
and/or each glass layer may be configured to be connected to both
the sense die 12 and the first substrate 30. The second substrate
20 may include two or more layers for any purpose. For example, the
second substrate 20 may include two or more layers in applications
where a first glass layer may be affixed to the sense die 12, a
second glass layer may be affixed to the first substrate 30, and
the first and second glass layers may be thereafter connected to
one another, where the connections are made in accordance with this
disclosure to form a stack 28 comprising the sense die 12, the
second substrate 20 (including at least the first and the second
glass layers), and the first substrate 30. In some cases where the
second substrate 20 includes a first portion 22 having a first
diameter D and a second portion 24 having a second diameter D' that
nay be greater than diameter D, the first glass layer may comprise
the first portion 22 and the second glass layer may comprise the
second portion 24.
[0023] Any intermediate layer of the second substrate 20 between
the two or more glass layers configured to be connected to the
sense die 12 and/or the first substrate 30 may be made of glass or
any other suitable material. Illustratively, any intermediate layer
may be made from a material that is able to be connected or affixed
to the glass layers without the use of adhesive, as media traveling
through the aperture 21 of second substrate 20 may be capable of
corroding adhesives and may undesirably weaken any seals between
layers of the second substrate 20. In addition, any intermediate
layer between the two or more glass layers may be made of a
material that is capable of being connected to the glass layers of
the second substrate 20 in a sealed (e.g., a hermetic sealed)
manner. Alternatively, or in addition, the various layers of second
substrate 20 (when more than one layer is present) may be coated
with a glass or other coating to facilitate bonding the second
substrate 20 to the first substrate 30 and the sense die 12, and/or
to help project the various layers of the second substrate 20 from
the media present in aperture 21.
[0024] In some instances, the sense die 12 having a first side 12a
and a second side 12b may include one or more sense elements,
generally shown at 16, and a sense diaphragm 14 (e.g., a pressure
sensitive sense diaphragm) having a first side 14a and a second
side 14b. The one or more sense elements 16 may be positioned
and/or configured to abut and/or be adjacent to the first side 14a
of sense diaphragm 14. The second side 14b of sense diaphragm 14
may be configured to receive a pressure from a media traveling
along media path 18, where the media path 18 may extend at least
from the second side 30b of first substrate 30 to the second side
14b of sense diaphragm 14 so as to apply a pressure to, and in some
cases be in direct contact with, the second side 14b of sense
diaphragm 14. The pressure sensor 10 may sense the pressure applied
to the second side 14b of sense diaphragm 14 through the sense
elements 16, facilitating a translation of a mechanical deflection
and/or stress of the diaphragm 14 in response to the applied
pressure into an electrical signal proportional or otherwise
related to the amount of the applied pressure.
[0025] Sense die 12 may be made from any suitable material. For
example, the sense die 12 may be formed from a silicon material, a
material including at least some silicon (e.g., a silicon blend),
GaAs, metal, and/or any other material having similar or dissimilar
properties. The sense diaphragm 14 maybe formed in sense die 12 by,
for example, etching, machining, or any other forming technique
configured to form the diaphragm 14 via the second side 12b of
sense die 12. In some cases, the sense elements 16 positioned
adjacent the first side 14a of sense diaphragm 14 may be
piezoresistive elements made from piezoelectric material and/or one
or more other materials that may be configured to change or modify
its electrical or other properties in response to a mechanical
stress or movement.
[0026] The layers of pressure sensor 10 may be connected with or
without the use of an adhesive. In some cases, as adhesives have
been shown to be susceptible to corrosion in pressure sensor
applications and as a result cause seals between layers of pressure
sensors to weaken, the layers of pressure sensor 10 may be
connected without the use of an adhesive.
[0027] An illustrative connection between the sense die 12 and the
second substrate 20 may include forming a joint through any
suitable technique that bonds any portion of the second side 12b of
sense die 12 to any portion of the first side 20a of second
substrate 20. In one example, the second side 12b of the sense die
12 may be joined to the first side 20a of second substrate 20
through an anodic bonding technique to create a silicon-glass joint
40 forming a seal (e.g., a hermetic seal) around media path 18. An
anodic bonding technique may be capable of bonding the sense die 12
to the second substrate 20 without the use of any intermediate or
intervening layers. Illustratively, an anodic bonding technique may
include abutting at least a portion of the second side 12b of sense
die 12 with at least a portion of the first side 20a of second
substrate 20 and then applying a voltage across the abutting
surfaces at one or more locations designated for forming a joint
therebetween. Before, during and/or after applying the voltage
across the abutting surfaces, a high temperature (e.g., a
temperature in the range of approximately 250-400 degrees Celsius,
200-500 degrees Celsius, 100-450 degrees Celsius, >100 degrees
Celsius, or any other suitable range of temperatures) may be
applied to one or more of the abutting surfaces (e.g., the first
side 20a of the second substrate 20 and the second side 12b of the
sense die 12) to facilitate forming a bond between the abutting
surfaces of the sense die 12 and the second substrate 20. Such a
technique may facilitate the direct bonding of glass molecules of
the second substrate 20 with silicon molecules of the sense die 12,
without any intervening adhesive layers.
[0028] Alternatively, or in addition, in some illustrative
instances, the second side 12b of sense die 12 may be joined to the
first side 20a of second substrate 20 through a frit bonding
technique to create the silicon-glass joint 40 forming a seal
(e.g., a hermetic seal) around media path 18. A frit bonding
technique may be capable of bonding the sense die 12 to the first
substrate without the use of any intervening adhesive layers.
Illustratively, a frit bonding technique may include applying a
frit paste on one or both of the first side 20a of second substrate
20 and the second side 12b of sense die 12. Then, once the frit
paste has been applied, the first side 20a of second substrate 20
and second side 12b of sense die 12 may be placed against one
another with the frit paste therebetween, and heat may be applied
to one or more of the first side 20a of second substrate 20, the
second side 12b of sense die 12, and the frit paste at or near the
joining area. Then, the second substrate 20, the sense die 12, and
frit paste may be cooled to facilitate solidifying the frit paste
and creating the silicon-glass joint 40. Such a technique may
facilitate the direct bonding of the glass molecules of the second
substrate 20 and the silicon molecules of the sense die 12 with the
molecules of the frit paste. Once the sense die 12 and the second
substrate 20 have been bonded or joined (e.g., through any suitable
technique, as desired), the aperture 21 of second substrate 20 may
be in fluid communication and/or in registration with the diaphragm
14 of sense die 12, as seen in FIGS. 1 and 3.
[0029] In some cases, a connection between the second substrate 20
and the first substrate 30 may include forming a metal-to-glass
joint 50 through any suitable technique (in some cases without an
adhesive) that is capable of bonding at least a portion of the
second side 20b of second substrate 20 to a portion of the first
side 30a of first substrate 30. In one example, the second side 20b
of second substrate 20 may be joined to the first side 30a of first
substrate 30 through a high temperature joining method, such as a
welding or soldering method to form the metal-to-glass joint 50
forming a seal (e.g., a hermetic seal) around media path 18. A high
temperature joining method or technique may be capable of bonding
the second substrate 20 to the first substrate 30 without the use
of any intermediate or intervening layers, such as adhesive layers.
Illustratively, a high temperature joining method or technique may
include fusing the second substrate 20 to the first substrate 30.
This may be accomplished by, for example, heating the second
substrate 20 (e.g., a glass substrate) until the second side 20b
begins to wet. After the second side 20b of second substrate 20
begins to wet, the first side 30a (e.g., a fusing surface) of first
substrate 30 may be applied to the wet portion of the second side
20b of second substrate 20 and then a joining area of the first
substrate 30 and the second substrate 20 (e.g., an area where the
first substrate 30 and the second substrate 20 are to be joined)
may be cooled to allow the glass molecules of the second substrate
20 to fuse to the metal molecules of the first substrate 30. Upon
cooling, a hermetically fused metal-to-glass joint 50 may be
created. Such a technique may facilitate the direct bonding of
glass molecules of the second substrate 20 with metal molecules of
the first substrate 30, without any intervening adhesive layers.
Once the second substrate 20 and the first substrate 30 have been
bonded or joined, the aperture 21 of second substrate 20 may be in
fluid communication or registration with the aperture 31 of first
substrate 30, as seen in FIGS. 1 and 3.
[0030] In some illustrative instances, once the stack 28 including
the sense die 12, the second substrate 20, the first substrate 30,
and the seals (e.g., hermetic seals) therebetween has been formed,
the stack 28 may be connected to a port 70 having a first side 70a
and a second side 70b, as shown in FIG. 3. Port 70 may be made of
one or more metal materials, or include a portion of metal
materials (e.g., metal materials may include aluminum, stainless
steel, a nickel-cobalt ferrous alloy such as KOVAR.RTM., any other
metal material, and/or any combination of metal materials) such
that port 70 may be connected to the stack 28 (e.g., the metal
first substrate 30) or a portion of the stack 28 through a welding,
soldering, or any other technique configured to create a seal
between two metal surfaces, where the seal may be a hermetic seal.
In some cases, the stack 28 may be connected to the first side 70a
of port 70. Once the stack has been connected with port 70, the
media path 18 through pressure sensor 10 may be substantially
completely formed so as to extend from the second side 70b of port
70 through the aperture 71 of port 70, through the aperture 31 of
first substrate 30, through the aperture 21 of second substrate 20,
and to the second side 14b of the sense diaphragm 14 of sense die
12. Although some of the illustrative examples describe port 70 as
being attached to a formed stack 28, port 70 may be connected to
the first substrate 30 at any time during the assembly of stack 28
(e.g., before or after any assembly of the sense die 12, the second
substrate 20, and the first substrate 30). Likewise, the order of
bonding the various components of the stack 28 may be changed, as
desired.
[0031] Once formed, the stack 28 may be able to sense a pressure
applied by media traveling through or about media path 18, by
utilizing the sense elements 16 on the first side 14a of sense
diaphragm 14. The sense elements 16 may translate a mechanical
stress and/or deflection of the sense diaphragm 14, caused by
pressure on the second side 14b of sense diaphragm 14 deflecting
the diaphragm 14, into electrical signals proportional or otherwise
related to the pressure on, at, or applied to the second side 14b
of sense diaphragm 14. In some cases, the produced electrical
signal may be transferred from the stack 28, through one or more
wire bonds or other electrical connection between sense die 12 and
a board 60. In some cases, the board 60 may be secured relative to
at least the first substrate 30 (e.g., the board 60 may be secured
on and/or relative to the top surface 30a''' of the first side 30a
of first substrate 30) of stack 28. The wire bonds may pair the
electrical signals from the stack 28 with processing signals for
compensation. The board 60 may be or may include a printed circuit
board ("PCB"), a processor, a ceramic substrate and/or any other
components configured to facilitate and/or receive an electrical
signal from the sense die 12 and/or compensate the signal as
desired. The wire bonding process may include attaching a first end
of one or more wire bonds 62 to one or more wire bond pads and/or
traces on the sense die 12, and a second end of one or more wire
bonds 62 to one or more bond pads and/or traces on the board
60.
[0032] After or, in some cases, before making a connection between
the sense die 12 and the board 60, a housing 80 may be placed at
least partially around the stack 28. As shown in FIG. 3, the
housing 80 may include a side wall 80a (e.g., a single side wall if
housing 80 is circular and multiple side walls if housing 80 takes
on shapes with one or more side edge (e.g., a rectangle, a
triangle, etc.)), a top wall 80b (e.g., there may be one or more
top walls 80b depending on the shape of the housing 80), and a
bottom wall 80c (e.g., there may be one or more bottom walls 80c
depending on the shape of the housing 80).
[0033] The housing 80 may connect to stack 28 at any location on
stack 28, where the connection is configured to isolate and/or
enclose the sense diaphragm 14 and one or more seals between the
sense die 12, the second substrate 20 and the first substrate 30.
For example, the housing 80 may connect to a side of the first
substrate 30 between the first side 30a and the second side 30b, as
shown in FIG. 3. Alternatively, or in addition, the housing 80 may
be attached to port 70, the second substrate 20, the board 60,
other portion(s) of the stack 28, and/or any other feature of
pressure sensor assembly 10, as desired.
[0034] In some cases, the housing 80 may include an external
electrical connection 90 extending from a top side 80b or other
side 80a, 80c of housing 80, as desired, to provide electrical
communication between the sense die 12, the board 60 and/or
external electronics. The external electrical connection 90 may be
connected to the board 60 through one or more electrical connection
links or lines 64. The one or more electrical connection lines 64
may be wireless and/or wired connection lines configured to connect
the external electrical connection 90 with the board 60 and/or the
sense die 12 to provide electrical contact with the outside world.
The external electrical connection 90 may be a plug having prongs,
a via filled with electrically conductive material, and/or any
other electrical connection configured to provide electrical
communication from external the housing 80 to internal the
housing.
[0035] It will be appreciated that variations of the
above-disclosed and other features and functions, or alternatives
thereof, may be desirably combined into many other different
systems or applications. Also that various presently unforeseen or
unanticipated alternatives, modifications, variations or
improvements therein may be subsequently made by those skilled in
the art which are also intended to be encompassed by the following
claims.
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