U.S. patent application number 13/464847 was filed with the patent office on 2012-10-18 for miniature chemical analysis system.
Invention is credited to Qing Ma, Li-Peng Wang.
Application Number | 20120263626 13/464847 |
Document ID | / |
Family ID | 37070719 |
Filed Date | 2012-10-18 |
United States Patent
Application |
20120263626 |
Kind Code |
A1 |
Wang; Li-Peng ; et
al. |
October 18, 2012 |
Miniature Chemical Analysis System
Abstract
An apparatus, according to one aspect, may include a
chromatograph and a bulk acoustic resonator. The chromatograph may
include a channel that is defined at least partially in a
monolithic substrate. The channel may have an inlet to receive a
sample and an outlet. A chromatography material may be included in
the channel. The bulk acoustic resonator may have a first electrode
and a second electrode that has a chemically functionalized
surface. The chemically functionalized surface may be included in a
chamber that is defined at least partially in the monolithic
substrate and that is coupled with the outlet of the channel.
Methods of making and using such apparatus, and systems including
such apparatus, are also disclosed.
Inventors: |
Wang; Li-Peng; (San Jose,
CA) ; Ma; Qing; (San Jose, CA) |
Family ID: |
37070719 |
Appl. No.: |
13/464847 |
Filed: |
May 4, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12750586 |
Mar 30, 2010 |
8178047 |
|
|
13464847 |
|
|
|
|
11096814 |
Mar 31, 2005 |
7695681 |
|
|
12750586 |
|
|
|
|
Current U.S.
Class: |
422/89 ; 216/2;
29/825 |
Current CPC
Class: |
G01N 2030/025 20130101;
G01N 2291/0256 20130101; B82Y 30/00 20130101; B82Y 15/00 20130101;
G01N 2291/0224 20130101; Y10T 29/49117 20150115; G01N 2291/0423
20130101; G01N 2291/0255 20130101; G01N 29/036 20130101; G01N
30/6095 20130101; G01N 29/022 20130101; G01N 2291/0426
20130101 |
Class at
Publication: |
422/89 ; 216/2;
29/825 |
International
Class: |
G01N 27/00 20060101
G01N027/00; B23P 15/00 20060101 B23P015/00; C30B 33/08 20060101
C30B033/08 |
Claims
1. An apparatus comprising: a chromatograph including a channel
that is defined at least partially in a monolithic substrate, the
channel having an inlet to receive a sample and an outlet, and the
chromatograph including a chromatography material in the channel;
and a bulk acoustic resonator having first electrode and a second
electrode that has a chemically functionalized surface that is
included in a chamber, wherein the chamber is defined at least
partially in the monolithic substrate and is coupled with the
outlet of the chromatograph.
2. The apparatus of claim 1, wherein the bulk acoustic resonator
comprises a film bulk acoustic resonator.
3. The apparatus of claim 1, wherein the first electrode comprises
one or more metal traces.
4. The apparatus of claim 1, further comprising a chemical
accumulator coupled with the inlet of the channel, the chemical
accumulator including a chamber that is defined at least partially
in the monolithic substrate and that has a chemical accumulation
material therein.
5. The apparatus of claim 4, further comprising: a first heater to
heat the chemical accumulation material; and a second heater to
heat the chromatography material.
6. The apparatus of claim 1, wherein the channel of the
chromatograph and the chamber of the bulk acoustic resonator are
each defined at least partially within the same piece of single
crystal silicon.
7. An apparatus comprising: a chromatograph including a channel
that is defined at least partially in a piece of single crystal
silicon, the channel having an inlet to receive a sample, the
channel having a material therein to affect progression of chemical
species of the sample through the channel, and the channel having
an outlet; one or more metal traces positioned relative to the
chromatograph to heat the material in the channel; and a film bulk
acoustic resonator (FBAR) detector, the FBAR detector including a
first electrode, a second electrode having a coated surface, and a
piezoelectric material disposed between the first and second
electrodes, the FBAR detector further including a chamber that is
defined at least partially in the piece of single crystal silicon,
the chamber having an inlet that is coupled with the outlet of the
chromatograph to receive the chemical species, wherein the coated
surface of the second electrode is exposed to the chemical species
received into the chamber.
8. The apparatus of claim 7, further comprising: a chemical
accumulator including a second chamber that is defined at least
partially in the piece of single crystal silicon, the second
chamber having an inlet to receive the sample, the chamber having a
sorbent therein to sorb the sample, and the chamber having an
outlet that is coupled with the inlet of the channel; and one or
more metal traces positioned relative to the chemical accumulator
to heat the sorbent.
9. The apparatus of claim 7, wherein the first electrode comprises
one or more metal traces.
10. The apparatus of claim 7, wherein the outlet of the channel and
the inlet of the chamber of the FBAR detector are coupled via a
microchannel.
11. A method comprising: forming a channel of a chromatograph at
least partially in a monolithic substrate by removing material of
the monolithic substrate; forming a chamber of a bulk acoustic
resonator at least partially in the monolithic substrate by
removing material of the monolithic substrate over an electrode of
the bulk acoustic resonator; introducing a chromatography material
into the channel of the chromatograph; and chemically
functionalizing a surface of the electrode of the bulk acoustic
resonator by coupling a material therewith.
12. The method of claim 11, further comprising forming a second
electrode of the bulk acoustic resonator by pattering a metal layer
into one or more metal traces.
13. The method of claim 11, wherein forming the channel and the
chamber in the monolithic substrate comprises etching a piece of
single crystal silicon.
14.-20. (canceled)
Description
BACKGROUND
[0001] 1. Field
[0002] Embodiments of the invention relate to miniature chemical
analysis systems, methods of making or using the miniature chemical
analysis systems, or systems including the miniature chemical
analysis systems.
[0003] 2. Background Information
[0004] Some miniature chemical analysis systems incorporate a
chromatograph and a surface acoustic wave resonator (SAW), which
are fabricated on different substrates instead of monolithically.
The chromatograph may separate chemical species and the SAW may
detect the chemical species. The surface of the SAW may be altered
to preferentially attach certain chemical species. Attachment of
the chemical species may change the frequency of the SAW, which may
be used for chemical analysis.
[0005] However, a SAW may potentially have certain disadvantages,
such as, for example, having relatively large insertion loss,
and/or having a frequency that is relatively insensitive to changes
in mass loading. This may potentially to reduce the sensitivity of
the chemical analysis.
[0006] Additionally, different types of chemical species may
potentially attach to the same altered surface of the SAW. This may
potentially hinder chemical detection and/or identification.
[0007] Still further, fabricated the chromatograph and SAW on
different substrates, instead of monolithically, may lead to
relatively large volumes of gas in the paths coupling the
substrates, which may potentially reduce sensitivity and adversely
affect chemical analysis, and/or which may potentially increase the
size of the chemical analysis system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0008] The invention may best be understood by referring to the
following description and accompanying drawings that are used to
illustrate embodiments of the invention. In the drawings:
[0009] FIG. 1 shows a cross-sectional view of a miniature chemical
analysis system formed monolithically on a silicon substrate,
according to one or more embodiments of the invention.
[0010] FIGS. 2-7 show cross-sectional views of substrates
representing different stages of a method of fabricating a
miniature chemical analysis system similar to that shown in FIG. 1,
according to one or more embodiments of the invention.
[0011] FIG. 8 shows a cross-sectional view of a miniature chemical
analysis system formed monolithically on a silicon-on-insulator
(SOI) substrate, according to one or more embodiments of the
invention.
[0012] FIGS. 9-15 show cross-sectional views of substrates
representing different stages of a method of fabricating a
miniature chemical analysis system similar to that shown in FIG. 8,
according to one or more embodiments of the invention.
[0013] FIG. 16 shows a chemical analysis system including a
reference FBAR detector, according to one or more embodiments of
the invention.
[0014] FIG. 17 shows a chemical analysis system having an
arrangement of FBAR detectors that allows sequential collection of
signals, according to one or more embodiments of the invention.
[0015] FIG. 18 shows a chemical analysis system having an
arrangement of FBAR detectors that allows simultaneous collection
of signals, according to one or more embodiments of the
invention.
[0016] FIG. 19 shows a chemical analysis system in which a
monolithically integrated chemical analysis system may be employed,
according to one or more embodiments of the invention.
[0017] FIG. 20 shows a container having a chemical analysis system
and a gas sealed or otherwise included therein, according to one or
more embodiments of the invention.
[0018] FIG. 21 shows an electronic device including a chemical
analysis system, according to one or more embodiments of the
invention.
DETAILED DESCRIPTION
[0019] In the following description, numerous specific details are
set forth. However, it is understood that embodiments of the
invention may be practiced without these specific details. In other
instances, well-known circuits, structures and techniques have not
been shown in detail in order not to obscure the understanding of
this description.
I. First Exemplary Chemical Analysis System
[0020] FIG. 1 shows a cross-sectional view of an exemplary
miniature chemical analysis system 100, according to one or more
embodiments of the invention. The miniature chemical analysis
system includes a sample inlet 148, an optional chemical
accumulator 152, a chromatograph 154, a film bulk acoustic
resonator (FBAR) detector 156, and a sample outlet 150. As shown,
portions of each of the chemical accumulator, the chromatograph,
and the FBAR detector may be defined at least partially in a
monolithic substrate 128.
[0021] As used herein, the term "substrate" may refer to a
workpiece object, such as, for example, a wafer or die, which may
have portions that have been transformed by a sequence of
operations or processes into miniature configurations, such as, for
example, circuits and/or structures. A "monolithic" substrate may
refer to a single piece of substrate, such as, for example, a
single piece of silicon, semiconductor, or other substrate
material. By way of example, the monolithic substrate may include a
single die, wafer, or other piece of single crystal of silicon.
[0022] In order to further illustrate certain concepts, the
chemical analysis system will be described in detail. The
description will begin with the sample inlet, proceed through the
chemical accumulator, chromatograph, and FBER detector, and finish
with the sample outlet.
[0023] The chemical analysis system may receive a gas or other
sample therein through the sample inlet 148. As shown, in one or
more embodiments, the sample inlet may include a manifold or other
opening in a coverplate 146. The coverplate may be bonded to or
otherwise coupled with the monolithic substrate. In one or more
embodiments of the invention, the sample inlet may be coupled with
a sample source such as, for example, via tubing, valves, pumps, or
the like. Alternatively, in one or more other embodiments, a
membrane may be placed over the sample inlet and a syringe may be
used to inject a sample therein.
[0024] The chemical accumulator 152 is coupled with the sample
inlet and may receive the sample. As shown, in one or more
embodiments of the invention, the chemical accumulator may be
integral with the monolithic substrate. As used herein, the
chemical accumulator is "integral" with the monolithic substrate
when at least a portion of the chemical accumulator is formed from
and/or in and/or on the monolithic substrate. As illustrated, a
chamber 134 of the chemical accumulator may be housed or otherwise
defined at least partially in the monolithic substrate.
[0025] The chemical accumulator includes a chemical accumulation
material 140 within the chamber. Suitable chemical accumulation
materials include, but are not limited to, sorbents and binding
agents. Suitable sorbents include absorbents, adsorbents, and
combinations thereof. The chemical accumulation material may sorb,
bind, or otherwise accumulate one or more chemical species of
interest from the sample selectively over one or more other
chemical species, such as, for example, air or a carrier gas.
Unsorbed chemical species may be removed, such as, for example,
through the sample outlet 150, or through another outlet (not
shown), which may optionally bypass the chromatograph.
[0026] The chemical accumulator may allow a chemical species to be
accumulated and concentrated, such as, for example, from a gas that
has the chemical species at low concentration and/or below a
detection limit. The sorbed or otherwise accumulated chemical
species may then be released at higher concentration and/or over
the detection limit, as a sample plug with a narrow temporal width,
which may help to reduce peak spreading within the chromatograph.
The released chemical species may be removed from the chemical
accumulator, such as, for example, a channel. Now, the chemical
accumulator is optional and may be omitted, such as, for example,
if the sample has the chemical species of interest above a
detection limit or threshold.
[0027] The illustrated chemical analysis system includes a heater
120B. The heater is formed on a patterned aluminum nitride layer
116, which has sufficient thermal conductivity to transfer heat
downward to the chemical accumulation material. The heater may be
used to heat the chemical accumulation material in order to help
release chemical species and to purge chemical species from the
material, such as, for example, to increase sensitivity. As shown,
in one or more embodiments, the heater may optionally include one
or more resistive heating elements, such as, for example, one or
more circuitous metal traces. The circuitous metal traces may be
positioned over the chamber. Throughout the following description,
it should be noted that terms such as "over", "under", "top",
"bottom", "upper", "lower", "vertical", "horizontal", and the like,
are used herein to facilitate the description of the system "as
illustrated". It will be evident that the systems may be used in a
variety of orientations including, but not limited to, inverted,
and vertical orientations.
[0028] The illustrated system also includes an optional heat
spreader 114A that is physically and thermally disposed between the
heater and the chemical accumulation material. In one or more
embodiments, the heat spreader may include a metal plate over the
chamber of the chemical accumulator. Suitable metals for the heat
spreader include, but are not limited to, molybdenum, gold,
platinum, copper, aluminum, titanium, chromium, palladium,
tungsten, and combinations thereof. These metals are also suitable
for the heater. The heat spreader may receive heat from the heater
and may spread or distribute heat to the chemical accumulation
material. Such spreading or distribution of the heat may promote
relatively more uniform heating of the material, and may allow more
time-resolved release of chemical species. However, the heat
spreader is not required.
[0029] The illustrated heat spreader is formed over, and directly
on, a patterned silicon nitride layer 112. As shown, the silicon
nitride layer may separate the heat spreader from the chemical
accumulation material. Silicon nitride has sufficient thermal
conductivity to transfer heat to the chemical accumulation
material, may provide mechanical strength and reliability to the
chemical analysis system, and is also somewhat electrically
insulating. However, the use of silicon nitride is not required.
Other materials besides silicon nitride may also optionally be used
including, but are not limited to, oxynitrides.
[0030] The chemical analysis system includes several other layers
that should be mentioned. The silicon nitride layer 112 is formed
over, and directly on, a patterned upper silicon dioxide layer 130.
The patterned upper silicon dioxide layer overlies, and is
superjacent to, the monolithic substrate 128. A patterned lower
silicon dioxide layer 132, underlies, and is subjacent to, the
monolithic substrate. The patterned lower silicon dioxide layer
overlies, is superjacent to, and may be bonded or otherwise
attached to, the coverplate 146. As will be discussed further
below, the silicon dioxide layers may be used as etch stop layers,
although other layers may also optionally be used.
[0031] Referring again to FIG. 1, the chemical analysis system also
includes the chromatograph 154. The chromatograph may be coupled
with an outlet of the chemical accumulator and may receive the
released chemical species. In one or more embodiments of the
invention, the released chemical species may at least potentially
include a mixture of two or more different chemical species. The
chromatograph may separate the chemical species of the mixture.
[0032] As shown, in one or more embodiments of the invention, the
chromatograph may be integral with the monolithic substrate. At
least a portion of the chromatograph may be formed from and/or in
and/or on the monolithic substrate. As illustrated, the
chromatograph may include a channel 136 that may be housed or
otherwise defined at least partially in the monolithic
substrate.
[0033] The channel may have an inlet (not shown), such as, for
example, at the left-hand side, and an outlet (not shown), such as,
for example, at the right-hand side. The inlet of the chromatograph
may be coupled with the outlet of the chemical accumulator, such
as, for example, through a channel, to receive chemical species.
The channel may have a length that is sufficient to temporally
separate chemical species of a mixture. Depending, at least in
part, upon the chemical species, the length of the channel may be
elongated and may range from about 0.1 to 10 meters, for example.
In order to help accommodate such lengths in small areas, the
channel may have a winding, serpentine, interlocked spiral, or
similar shape.
[0034] A chromatography material 142, which is also sometimes known
in the art as a stationary-phase material, may be included in the
channel. A wide variety of well-known chromatography materials are
suitable. As shown, the chromatography material may optionally coat
at least a portion of the walls and/or the ceiling of the channel.
However, it is not required that the chromatography material be
included in these locations, or in just these locations.
[0035] The chromatography material may affect the progression
and/or the velocity of the chemical species through the channel
based at least in part on their chemical properties. Each of the
chemical species may have a different affinity and interaction with
the chromatography material, and may correspondingly be delayed in
the channel for a different period of time. This may allow the
chemical species to be temporally separated. The temporally
separated chemical species may be eluted or otherwise removed
sequentially from the outlet of the chromatograph as a series of
time-resolved peaks.
[0036] The illustrated system further includes an optional heater
120D over the chromatograph, and an optional heat spreader 114B
disposed between the heater and the chromatograph. The heater and
heat spreader may optionally have some or all of the
characteristics of the corresponding heater and heat spreader
described above. The chromatography material may optionally be
heated during a separation, such as, for example, to improve or
otherwise alter the separation, and/or optionally after a
separation, such as, for example, to purge chemical species from
the chromatography material, such as, for example, to help reduce
contamination.
[0037] With continued reference to FIG. 1, the chemical analysis
system further includes the FBAR detector 156. The FBAR detector
may be coupled with the outlet of the chromatograph and may receive
the temporally separated chemical species from the
chromatograph.
[0038] As shown, in one or more embodiments of the invention, the
FBAR detector may be integral with the monolithic substrate. At
least a portion of the FBAR detector may be formed from and/or in
and/or on the monolithic substrate. As illustrated, a chamber 138
of the FBAR detector may be housed or otherwise defined at least
partially in the monolithic substrate. The chamber of the FBAR
detector is defined in part by a patterned layer 112, which
provides a structural membrane, and which is also formed monolithic
over the silicon substrate.
[0039] Forming or otherwise providing the FBAR detector integral
with the chemical accumulator and/or chromatograph may offer
certain potential advantages. For one thing, this may allow a
smaller or more miniaturized chemical analysis system. For another
thing, this may help to improve chemical sensitivity and analysis.
Often the FBAR detector may be coupled with the chromatograph via a
microchannel defining a small volume of gas. The amount of gas may
be substantially less than would be present in a path coupling an
off-substrate resonator with the chromatograph if they were not
monolithically integrated.
[0040] The FBAR detector also includes a first, upper electrode
120F, and a second, lower electrode 114C having a coated or
otherwise chemically functionalized surface. The electrodes may
each include a metal or other conductive material.
[0041] As shown, in one or more embodiments of the invention,
rather than a planar electrode, the upper electrode 120F may
optionally include one or more circuitous metal or otherwise
conductive traces over the lower planar electrode. The circuitous
metal traces may optionally be used as resistive heating elements
to heat the lower electrode, such as, for example, to help control
the temperature of the FBAR detector. As further shown, in one or
more embodiments, the lower electrode of the FBAR detector may
optionally be formed in an opening in a silicon nitride layer 112.
Although not required, this may potentially help to reduce acoustic
energy loss from the FBAR detector.
[0042] In one or more embodiments, the heater 120B of the chemical
accumulator, the heater 120D of the chromatograph, and the upper
electrode 120F of the FBAR detector may optionally be formed from a
single first patterned metal layer. Likewise, the heat spreader
114A of the chemical accumulator, the heat spreader 114B of the
chromatograph, and the lower electrode 114C of the FBAR detector
may optionally be formed from a single second patterned metal
layer. In one or more embodiments of the invention, in order to
provide an FBAR detector with relatively low acoustic energy loss,
either or both of the first and second patterned metal layers may
include a metal that provides a substantially low acoustic energy
loss, such as, for example, molybdenum or tungsten. This may help
to provide an FBAR detector with a relatively high Q-value.
However, the scope of the invention is not limited in this respect.
Additionally, there is no requirement that the electrodes and the
heaters and/or heat spreaders be formed from single layers or
include the same metal.
[0043] Disposed immediately between the upper and lower electrodes
is a portion of the patterned aluminum nitride layer 116. The
aluminum nitride layer also overlies, and is superjacent to, both
the silicon nitride layer 112 and the heat spreaders 114A, 114B.
The aluminum nitride layer also underlies, and is subjacent to, the
heaters 120B, 120D.
[0044] Aluminum nitride (AlN) is a piezoelectric material. During
operation, when a signal is applied to the electrodes, the FBAR
detector may resonate at a particular frequency. As is known, the
resonance frequency may depend upon the thickness of the material
between the electrodes and on the properties of the material, such
as, for example, acoustic velocity. For aluminum nitride, a
sufficient thickness may range from about 1 to 3 .mu.m, although
the scope of the invention is not limited to just these thickness.
Other suitable piezoelectric materials besides aluminum nitride
include, but are not limited to, zinc oxide (ZnO), piezoceramic,
such as, for example, lead-zirconate titanate (PZT), and
quartz.
[0045] Now, the FBAR detector may be used to sense, detect,
identify, or otherwise chemically analyze at least one or all of
the chemical species received into the chamber. The lower electrode
has the chemically functionalized surface 144. In various
embodiments of the invention, the chemically functionalized surface
may include a material, coating, layer, monolayer, or surface
treatment that is applied to, formed over, or otherwise included
over the lower electrode. Different approaches for forming the
chemically functionalized surface are described further below.
[0046] The chemically functionalized surface is included in the
chamber of the FBAR detector and is accessible to chemical species
therein. The chemical species may potentially react, bind, sorb, or
otherwise attach to or couple with the chemically functionalized
surface. Such attachment may change the resonance frequency of the
FBAR detector due, at least in part, to a change in mass loading.
Typically, the attachment will result in a decrease in the
resonance frequency. The change in the resonance frequency may be
determined and used to analyze the chemical species, such as, for
example, to quantitatively detect the chemical species. In one or
more embodiments of the invention, the chemically functionalized
surface may specifically attach one molecule or a small subset of
molecules and the change may allow chemical identification.
Additional information, such as, for example, time to elute from
the chromatograph may also optionally be used to facilitate
chemical identification.
[0047] FBAR detectors may offer certain potential advantages over
other resonators that have been used for chemical analysis. For one
thing, FBAR detectors may tend to have relatively smaller insertion
loss, such as, for example, substantially less than 35 dB. Further,
the resonance frequencies of FBAR detectors may tend to be
relatively more sensitive to changes in mass loading. Other bulk
acoustic resonators may offer similar advantages and are suitable
for embodiments of the invention.
[0048] Referring again to FIG. 1, an outlet of the chamber of the
FBAR detector may be coupled with the sample outlet 150 to allow
chemical species to be removed from the chemical analysis system.
As shown, in one or more embodiments, the sample outlet may include
a manifold or other opening in the coverplate. In one aspect, the
manifold or opening may allow the chemical analysis system to be
coupled with an external sample destination where the sample or a
portion thereof may be disposed. External coupling devices, such
as, for example, tubing, valves, pumps, and like devices, and
combinations thereof, may be used for the coupling.
[0049] With continued reference to FIG. 1, the chemical analysis
system further includes optional seed materials 120A, 120C, 120E,
and 120G. In one or more embodiments of the invention, the seed
materials may be part of the same patterned metal layer as the
heaters and upper electrode. Over, and directly on, the seed
materials are bonding pads 126A, 126B, 126C, and 126D. In one or
more embodiments of the invention, the bonding pads may optionally
be plated or otherwise formed over, or directly on, the seed
materials. The bonding pads and seed materials together represent
signaling paths or signaling mediums that may be used to
communicate signals to and/or from the chemical analysis system.
The signals may be used to provide control and/or other information
to the chemical analysis system from external circuits and/or to
deliver chemical analysis results and/or other information from the
chemical analysis system to external circuits.
II. Method of Forming First Chemical Analysis System
[0050] FIGS. 2-7 show cross-sectional views of substrates
representing different stages of a method of fabricating a chemical
analysis system similar to that shown in FIG. 1, according to one
or more embodiments of the invention. In these figures, certain
reference numerals have been repeated to indicate that components
may correspond.
[0051] FIG. 2 shows a view of a monolithic silicon substrate 102,
an upper silicon dioxide layer 104, a lower silicon dioxide layer
106, an upper silicon nitride layer 108, and a lower silicon
nitride layer 110, according to one or more embodiments of the
invention. The silicon dioxide layers may be formed on the
monolithic silicon substrate by deposition or thermal growth. A
sufficient thickness may be, for example, between about 0.3 to 2
.mu.m. The silicon nitride layers may be deposited on the silicon
dioxide layers, such as, for example, by using low-pressure
chemical vapor deposition (LPCVD). A sufficient thickness may be,
for example, between about 0.5 to 4 .mu.m.
[0052] FIG. 3 shows a view after selectively etching the silicon
nitride layers of the substrate of FIG. 2, and then forming a
patterned metal layer over the upper surface of the resulting
substrate, according to one or more embodiments of the invention.
During the silicon nitride etch, the lower silicon nitride layer
may be entirely removed using the lower silicon dioxide layer as an
etch stop. An opening may also be etched in the upper silicon
nitride layer in a region that is to contain the lower electrode
114C of the FBAR detector. A patterned resist layer or other
patterned mask may be used to perform the patterned etch of the
upper silicon nitride layer also using the upper silicon dioxide
layer as an etch stop.
[0053] Then, after etching the upper silicon nitride layer, a
patterned metal layer may be formed over the upper surface of the
resulting substrate. Initially, a metal layer may be deposited over
the upper surface, such as, for example, by evaporation or
sputtering. Then, the metal layer may be patterned, such as, for
example, by photolithography and lift-off or etching. As shown, the
resulting patterned metal layer may include a first metal portion
114A corresponding to the heat spreader of the chemical
accumulator, a second metal portion 114B corresponding to the heat
spreader of the chromatograph, and a third metal portion 114C
corresponding to the lower electrode of the FBAR detector.
[0054] FIG. 4 shows a view after forming a patterned aluminum
nitride layer 116 over the substrate of FIG. 3, forming a patterned
metal layer 120A-G over the aluminum nitride layer, and plating or
otherwise forming bonding pads 126A-D over corresponding seed
material portions 120A, 120C, 120E, and 120G of the patterned metal
layer, according to one or more embodiments of the invention.
First, the aluminum nitride layer may be deposited, such as, for
example, by reactive sputtering. A sufficient thickness may range
from about 0.5 to 3 .mu.m, for example. Then, an opening may be
formed through the aluminum nitride layer proximate the lower
electrode 114C of the FBAR detector, such as, for example, by
performing a patterned etch according to a patterned mask.
[0055] Then, the patterned metal layer may be formed over the
aluminum nitride layer either before, but typically after, the
patterning of the aluminum nitride layer. The patterned metal layer
may include seeds materials 120A, 120C, 120E, and 120G. The
patterned metal layer may also include circuitous metal traces
120B, 120D, and 120F, which correspond to the chemical accumulator,
chromatograph, and FBAR detector, respectively. The patterned metal
layer may also include metal in the opening in the aluminum nitride
layer to provide a signal path or medium to the lower electrode. In
one or more embodiments of the invention, the thickness of a
patterned metal layer may range from about 0.1 to 0.4 .mu.m,
although the scope of the invention is not limited in this respect.
The width of the metal traces may vary depending upon the
implementation and may optionally be different for the chemical
accumulator, the chromatograph, and/or the FBAR detector. The
bonding pads may then be formed over the seed materials, such as,
for example, by plating.
[0056] FIG. 5 shows a view after forming openings in the backside
of the substrate of FIG. 4, according to one or more embodiments of
the invention. The openings include a first opening 134
corresponding to the chamber of the chemical accumulator, a second
opening 136 corresponding to the channel or column of the
chromatograph, and a third opening 138 corresponding to the chamber
of the FBAR detector. The openings are each formed at least in part
by removing material of the monolithic substrate. In one or more
embodiments of the invention, a patterned resist layer or other
patterned mask may be formed over a lower surface of the substrate,
such as, for example, over the lower silicon dioxide layer 132, and
then an etch may be performed to form the openings according to the
patterned resist layer. In one or more embodiments, a deep reactive
ion etch (DRIE) may optionally be used to obtain different etch
rates, such as, for example, as a function of the aspect ratio of
the openings, although this is not required. As shown, this may
optionally allow deeper openings to be formed for the chambers than
for the channel.
[0057] FIG. 6 shows a view after introducing materials into the
openings of the substrate of FIG. 5, according to one or more
embodiments of the invention. A chemical accumulation material 140
has been introduced into the chamber of the chemical accumulator. A
chromatography material 142 has been introduced into the channel of
the chromatograph. A material has been introduced to provide a
chemically functionalized surface 144 on the lower electrode of the
FBAR detector. Note that it is not required that the materials be
introduced in the positions illustrated, or only in the positions
illustrated.
[0058] Depending at least in part on the particular material,
suitable approaches for introducing materials include, but are not
limited to, localized syringe, nanodispensing, spin coating, dip
coating, localized spray coating, and combinations of such
approaches. In one or more embodiments, the materials are
introduced sequentially, in order to help avoid thermal damage to a
previously introduced material. Materials that are relatively more
thermally stable, and/or that are applied at a higher temperature,
may optionally be applied before materials that are less thermally
stable, and/or that are applied at a lower temperature. In some
instances, drying may optionally be used to remove liquid from the
materials.
[0059] Various approaches may be used to chemically functionalize
the electrode surface. In general, the surface may be chemically
functionalized by introducing one or more different types of
molecules, biomolecules, or other materials thereto.
[0060] One approach may include self-assembling molecular or
biomolecular layers on the surface. Suitable biomolecules include,
but are not limited to, amino acid derivatized fatty acids, amino
acid derivatized lipids, and other molecules.
[0061] Another approach may include forming a self-assembled
monolayer on the surface and then immobilizing molecules or
biomolecules on the self-assembled monolayer. Examples of suitable
molecules include, but are not limited to, a variety of polymeric
molecules. Examples of suitable biomolecules include, but are not
limited to, antibodies and DNA molecules. Other suitable
biomolecules include fragments and derivatives of such
biomolecules. As one example, a self-assembled monolayer of a
thiol, sulfide, or like species may be formed on the electrode
surface, such as, for example, by chemisorption, and then
antibodies, DNA molecules, or other biomolecules may be covalently
linked to the self-assembled monolayer using an activation process.
The antibodies or DNA molecules may provide a relatively specific
chemically functionalized surface that may target a specific
molecule or a substantially small group of molecules.
[0062] Yet another approach may include forming an organic membrane
on the surface. The organic membrane may be formed by pre-coating,
chemical derivatization, or photobonding, to name just a few
examples. Examples of chemical derivatization include, but are not
limited to, silylation, acylation, esterification or
alkylation.
[0063] A further approach may include forming an organic membrane
on the surface, and then immobilizing molecules or biomolecules on
the organic membrane. A still further approach may include direct
immobilization of molecules or biomolecules on metal. Another
approach may include direct immobilization of biomolecules on a
non-metallic inorganic film. Still other approaches include, but
are not limited to coating or applying organic, polymeric,
halogenated polymeric, organometallic, inorganic, silicone, and
metal materials over the surface of the electrode. Still further
approaches known in the art for functionalizing surfaces of SAWs
may also optionally be used.
[0064] FIG. 7 shows a view after attaching a coverplate 146 having
a sample inlet manifold or opening 148 and a sample outlet manifold
or opening 150 therein to the backside of the substrate of FIG. 6,
according to one or more embodiments of the invention. In one or
more embodiments of the invention, the coverplate may include a
glass substrate that may be attached with anodic bonding, although
this is not required. Other suitable substrates include, but are
not limited to, quartz substrates, organic substrates, and metal
substrates, which may be attached with adhesives or otherwise.
III. Second Exemplary Chemical Analysis System
[0065] FIG. 8 shows a cross-sectional view of an exemplary
miniature chemical analysis system 200 having an optional chemical
accumulator 243, a chromatograph 245, and an FBAR detector 247 that
are each integral with a patterned silicon-on-insulator (SOI)
substrate 249, according to one or more embodiments of the
invention. Many of the components of the chemical analysis system
200 may optionally have some or all of the characteristics of the
correspondingly named components of the chemical analysis system
100 shown in FIG. 1. To avoid obscuring the following description,
the different and/or additional characteristics and structures of
the chemical analysis system 200 will be emphasized.
[0066] The illustrated chemical analysis system includes a
coverplate 237 having a sample inlet 239 and sample outlet 241. As
shown, the coverplate may be coupled with a backside of the
patterned SOI substrate through an intervening patterned lower
silicon dioxide layer 231.
[0067] The patterned SOI substrate includes patterned active
silicon 211, patterned buried insulator 229, and patterned bulk
silicon 227. As shown, the patterned SOI substrate has been
transformed during fabrication of the chemical analysis system. The
chemical analysis system is formed monolithically integral with the
SOI substrate. As shown, portions of each of the chemical
accumulator, chromatograph, and FBAR detector are integral with the
patterned SOI substrate.
[0068] The chemical accumulator includes a chamber 225 that is
housed or defined at least partially within the patterned SOI
substrate. A sorbent or other chemical accumulation material 231 is
included in the chamber. An optional heater 221B, such as, for
example, including one or more circuitous metal traces, is
positioned over the chamber to heat the chemical accumulation
material. An optional heat spreader 217A is disposed between the
heater and the chamber to spread or otherwise distribute heat.
[0069] The chromatograph includes a channel or column 251 that is
housed or defined at least partially within the patterned SOI
substrate. A chromatography material 233 is included in the
channel. An optional heater 221D, such as, for example, including
one or more circuitous metal traces, is positioned over the channel
to heat the chromatography material. An optional heat spreader 217B
is disposed between the heater and the channel to spread or
otherwise distribute heat.
[0070] The FBAR detector includes a chamber 229, which is housed or
defined at least partially within the patterned SOI substrate, a
lower electrode 217C, and an upper electrode 221F. As viewed, the
lower electrode forms a ceiling for the chamber and has a
chemically functionalized surface 235. In one or more embodiments
of the invention, the upper electrode may optionally include one or
more circuitous metal traces that may be used to heat the lower
electrode, such as, for example, to control its temperature and/or
release attached chemical species.
[0071] In the illustrated embodiment, a patterned upper silicon
dioxide layer 213 is included over, and directly on, the patterned
active silicon 211. The upper silicon dioxide layer may be used as
an etch stop, although other etch stops may also be used. The
patterned upper silicon dioxide layer is disposed immediately
between the heat spreaders and the underlying patterned active
silicon. An opening is included through both the patterned upper
oxide layer and the patterned active silicon to accommodate the
lower electrode of the FBAR detector. Removing the oxide and active
silicon in this region may help to reduce acoustic energy loss and
may help to provide a resonator with a relatively higher Q-value,
although this is not required.
[0072] The chemical analysis system also includes a patterned
aluminum nitride layer 219. The patterned aluminum nitride layer is
included over, and directly on, a portion of the patterned upper
oxide layer 213, and over, and directly on, the heat spreaders
217A, 217B and lower electrode 217C, which may be part of the same
patterned metal layer. The illustrated patterned aluminum nitride
layer is disposed immediately between the heaters and the heat
spreaders of the chemical accumulator and chromatograph.
Additionally, the illustrated patterned aluminum nitride layer
separates the upper and lower electrodes of the FBAR detector. As
discussed above, other piezoelectric materials besides aluminum
nitride may also optionally be used.
[0073] As shown, in one or more embodiments of the invention,
vertical trenches or other openings may optionally be included
around peripheries of the heaters and heat spreaders. As shown, the
trenches may optionally be formed down through the active silicon,
although this is not required. The trenches may help to favor heat
transfer from the heater to the materials included in the chambers
and/or channel and may help to reduce conduction of heat in the
horizontal direction or otherwise away from the materials in the
chamber and/or channel.
[0074] Seed materials 221A, 221C, 221E, and 221G may be included
over, and directly on, the patterned aluminum nitride layer. In one
or more embodiments of the invention, the seed materials may be
part of the same patterned metal layer as the heaters of the
chemical accumulator and chromatograph and upper electrode of the
FBAR detector. Bonding pads 223A, 223B, 223C, and 223D may be
plated or otherwise formed over, or directly on, the corresponding
underlying or subjacent seed materials.
[0075] Compared to a standard silicon substrate, the SOI substrate
may tend to provide a mechanically stronger and potentially more
reliable chemical analysis system. The patterned active silicon
layer may tend to exhibit good mechanical strength. However, the
SOI substrate may tend to be more costly than a standard silicon
substrate.
IV. Method of Forming Second Exemplary Chemical Analysis System
[0076] FIGS. 9-15 show cross-sectional views of substrates
representing different stages of a method of fabricating a chemical
analysis system similar to that shown in FIG. 8, according to one
or more embodiments of the invention. In these figures, certain
reference numerals have been repeated to indicate that components
may correspond. Certain operations, such as, for example, forming
layers, patterning layers, and the like, may be similar to
operations that have already been described above. For brevity, the
following description may tend to emphasize different and/or
additional details.
[0077] FIG. 9 shows a view of an SOI substrate 201 having an upper
silicon dioxide layer 209 and a lower silicon dioxide layer 205
formed thereon, according to one or more embodiments of the
invention. The SOI substrate includes an active silicon layer 207,
a buried silicon dioxide layer 203, and a bulk silicon layer 202.
The upper and lower silicon dioxide layers may be formed on the SOI
substrate by thermal growth or deposition.
[0078] FIG. 10 shows a view after optionally etching or otherwise
forming openings 215A-E in the upper surface of the substrate of
FIG. 9, according to one or more embodiments of the invention. A
first trench 215A, 215B may optionally be formed through the upper
silicon dioxide layer and the active silicon layer around a
periphery over the intended location of the chamber of the chemical
accumulator. A second trench 215C, 215D may optionally be formed
through the upper silicon dioxide layer and the active silicon
layer around a periphery over the intended location of the channel
of the chromatograph. As discussed above, these trenches, which are
optional, may help to provide thermal insulation. An opening 215E
may optionally be formed through the upper silicon dioxide layer
and the active silicon layer in a region intended for the lower
electrode of the FBAR detector. This opening may help to reduce
acoustic energy loss and improve the Q-value of the FBAR detector,
although it is not required.
[0079] FIG. 11 shows a view after forming a patterned metal layer
217A-C over, and directly on, the upper surface of the substrate of
FIG. 10, according to one or more embodiments of the invention. The
patterned metal layer includes a first heat spreader 217A over the
intended location of the chamber of the chemical accumulator, a
second heat spreader 217B over the intended location of the channel
of the chromatograph, and a lower electrode 217C over the intended
location of the chamber of the FBAR detector.
[0080] FIG. 12 shows a view after forming a patterned aluminum
nitride layer 219 over the substrate of FIG. 11, forming a
patterned metal layer 221A-G over the aluminum nitride layer, and
plating or otherwise forming bonding pads 223A-D over seed
materials 221A, 221C, 221E, and 221G of the patterned metal layer,
according to one or more embodiments of the invention. In one or
more embodiments, the aluminum nitride layer may be patterned by
using the patterned oxide layer 213 as an etch stop, although this
is not required. As shown, in one or more embodiments, trenches or
other openings may optionally be formed through the aluminum
nitride layer over the existing trenches or openings. An opening
may optionally be formed over the FBAR detector.
[0081] FIG. 13 shows a view after etching or otherwise forming
chamber 225, 229 and channel 251 openings in the backside of the
substrate of FIG. 12, according to one or more embodiments of the
invention. The illustrated openings are formed through the lower
silicon dioxide layer, the bulk silicon layer, and the buried
silicon dioxide layer, although this is not required. In one or
more embodiments of the invention, the openings may be formed by
first performing a silicon etch according to a patterned mask in
order to etch through the lower silicon dioxide layer and the bulk
silicon layer, and then a silicon dioxide etch may be performed
with the self-aligned bulk silicon as a mask to etch through the
buried silicon dioxide layer. The etching through the silicon
dioxide layer may expose the lower electrode of the FBAR
detector.
[0082] FIG. 14 shows a view after introducing a chemical
accumulation material 231 into the chamber 225 of the chemical
accumulator, introducing a chromatography material 233 into the
channel 251 of the chromatograph, and chemically functionalizing a
surface 235 of the lower electrode of the FBAR detector, according
to one or more embodiments of the invention. The approaches
described above may optionally be used.
[0083] FIG. 15 shows a view after coupling a coverplate 237 having
a sample inlet 239 and a sample outlet 241 to the backside of the
substrate of FIG. 14, according to one or more embodiments of the
invention. The approaches described above may optionally be
used.
[0084] Now, the scope of the invention is not limited to the just
the particular chemical analysis systems illustrated above. Many
alternate chemical analysis systems are contemplated in which
structures are omitted, rearranged, or added. Additionally,
analogous chemical analysis systems may be formed on substrates
other than standard silicon and SOI substrates.
V. Exemplary Chemical Analysis Systems Including Multiple FBAR
Detectors
[0085] For simplicity, the chemical analysis systems above were
described in terms of a single FBAR detector. However, in one or
more embodiments of the invention, the chemical analysis systems
described above, as well as other chemical analysis systems, may
include multiple FBAR detectors. By way of example, the multiple
FBAR detectors may be used to provide a reference FBAR detector
and/or to provide FBAR detectors with different chemically
functionalized surfaces.
[0086] In some implementations, the resonance frequency of an FBAR
detector may be affected by environmental conditions, such as, for
example, changes in temperature. Additionally, the resonance
frequencies of FBAR detectors may sometimes vary within a wafer
and/or from wafer to wafer due, at least in part, to unintended
variation FBAR detector structure, such as, for example, film
thickness, which may potentially arise from heterogeneous process
conditions during device fabrication.
[0087] FIG. 16 shows a chemical analysis system 1660 including an
optional reference or control FBAR detector 1662 without a
chemically functionalized electrode surface, an FBAR detector 1664
with a chemically functionalized electrode surface 1665, and
circuitry to utilize the resonance frequencies of the FBAR
detectors, according to one or more embodiments of the
invention.
[0088] In one or more embodiments of the invention, the reference
and chemically functionalized FBAR detectors may be fabricated
proximate to one another within the chemical analysis system. As
used herein, FBAR detectors are proximate to one another when they
are within not more than 2 centimeters, such as, for example,
within not more than 1 centimeter, or within 0.5 centimeters. The
proximate FBAR detectors may tend to have about the same
temperature and about the same structure due to similar process
conditions during fabrication.
[0089] The reference FBAR detector may have a reference resonance
frequency (f0), and the chemically functionalized FBAR detector may
have a resonance frequency (f1). The frequency f1 may depend upon
the attachment of a chemical species to the chemically
functionalized surface. After optional amplification, a first
signal representing the reference resonance frequency (f0) and a
second signal representing the resonance frequency (f1) may be
provided to a mixer 1666.
[0090] The mixer may potentially generate two signals representing
the sum of the frequencies (f0+f1) and the difference of the
frequencies (f0-f1), although these particular signals are not
required. The sum and difference of the frequencies may be provided
to a low pass filter 1668. The low pass filter may filter out the
sum and provide the difference to a frequency counter 1670.
[0091] The differencing of the frequencies may help to reduce at
least some of the affect on the resonance frequencies due to
changes in environmental conditions (for example temperature)
and/or due to variation in device structure. The affect of these
factors may be similar on both resonance frequencies and may be
substantially removed during the differencing process. This may
potentially help to improve the accuracy and/or precision of the
chemical analysis.
VI. First Exemplary Arrangement of FBAR Detectors
[0092] In some cases, different types of chemical species may
potentially attach similarly to the same chemically functionalized
surface. For example, a gas may not have a one-to-one correlation
with a functionalized coating and the coating may not allow unique
identification of the gas. However, it is generally much less
likely that the different types of chemical species will attach
similarly to all of a variety of different chemically
functionalized surfaces. In one or more embodiments of the
invention, a chemical analysis system may include multiple FBAR
detectors with differently chemically functionalized electrode
surfaces in order to help distinguish one type of chemical species
from other types. The multiple FBAR detectors may help to provide a
relatively more unique signature for a particular chemical species
than a single FBAR detector with a single functionalized
surface.
[0093] FIGS. 17-18 show chemical analysis systems with different
exemplary arrangements of FBAR detectors having differently
chemically functionalized electrode surfaces.
[0094] FIG. 17 shows a chemical analysis system 1772 having a first
arrangement of FBAR detectors having differently chemically
functionalized electrode surfaces, which allows sequential
collection of signals from the FBAR detectors, according to one or
more embodiments of the invention. The system includes an optional
reference FBAR detector 1762, four chemically functionalized FBAR
detectors 1764A-D that each have one of four corresponding
different chemically functionalized electrode surfaces 1765A-D, a
switch multiplexer 1774, a mixer 1766, a low pass filter 1768, and
a frequency counter 1770.
[0095] The four differently chemically functionalized FBAR
detectors are each coupled with the switch multiplexer. Each of the
chemically functionalized FBAR detectors may provide a signal
representing a resonance frequency to the switch multiplexer. In
particular, a first FBAR detector 1764A may provide a signal
representing a first resonance frequency (f1) to the switch
multiplexer, a second FBAR detector 1764B may provide a signal
representing a second resonance frequency (f2) to the switch
multiplexer, and so on. A given type of chemical species may tend
to attach at least somewhat differently to the four differently
chemically functionalized electrodes than other types of chemical
species. This generally tends to become even more true when more
than four differently chemically functionalized electrodes are
included, such as, for example, ten, twenty, or more.
[0096] The switch multiplexer is coupled with the mixer. The switch
multiplexer may gather or otherwise collect the signals from the
chemically functionalized FBAR detectors. In one or more
embodiments, the switch multiplexer may collect the signals
sequentially and in any desired order. In one or more embodiments
of the invention, the switch multiplexer may optionally include
logic to collect signals from a pertinent subset of the chemically
functionalized FBAR detectors. The subset may be selected, for
example, based on information about the particular chemical
analysis performed, a particular chemical species of interest, or
the like.
[0097] The switch multiplexer may provide the signals to the mixer.
In one or more embodiments, the switch multiplexer may provide the
signals sequentially. The mixer may optionally sequentially compare
the resonance frequencies in turn with the reference resonance
frequency that is provided to the mixer from the reference FBAR
detector. For example, as shown in the illustrated embodiment, the
mixer may determine a sum of the frequencies (f0+fn) and a
difference of the frequencies (f0-fn), where fn may represent any
one of the resonance frequencies f1, f2, f3, or f4. Each sum and
difference may optionally be sequentially provided to the low pass
filter, and then each difference may optionally be sequentially
provided to the frequency counter, as previously described.
[0098] The resulting resonance frequency difference data collected
through the frequency counter for the differently chemically
functionalized FBAR detectors may be combined in order to generate
a fingerprint or signature. A simple example of a fingerprint
includes a list of frequency differences corresponding to the
differently chemically functionalized FBAR detectors. The
fingerprint may tend to be relatively more unique to the chemical
species than data collected for any single chemically
functionalized FBAR detector. At least to a point, a larger and
more diverse set of differently chemically functionalized FBAR
detectors may tend to provide a relatively more unique fingerprint
that is better suited for chemical analysis.
[0099] The resulting fingerprint may be used for a variety of
different purposes. In one or more embodiments of the invention,
the fingerprint or signature may optionally be used for chemical
analysis, such as, for example, chemical detection and/or
identification. A method, according to one or more embodiments of
the invention, may include comparing a determined fingerprint to
one or more predetermined fingerprints, for example in a library,
that each correspond to a different one or more known chemical
species. In one or more embodiments of the invention, the method
may further optionally include making an inference about detection
and/or identification based on the comparison, although this is not
required. For example, if the fingerprints match within a
prescribed tolerance or uncertainty, then it may be inferred that
the unknown chemical species was detected, or the identity of the
unknown chemical species may be inferred to be the same as the
known chemical species.
[0100] As another option, in one or more embodiments of the
invention, the fingerprint or signature may be stored in a
machine-accessible and/or machine-readable medium. In one aspect,
fingerprints or signatures may be stored for different chemical
species in order to generate a library that may be used in the
future. The scope of the invention is not limited to detecting or
identifying chemical species, additionally, even if detection or
identification is desired, chromatography, and other information
may be used to supplant the information from the FBAR detectors in
order to improve the capability for detection and/or
identification.
VII. Second Exemplary Arrangement of FBAR Detectors
[0101] FIG. 18 shows a chemical analysis system 1876 having an
arrangement of FBAR detectors having differently chemically
functionalized electrode surfaces that allows simultaneous
collection of signals from the FBAR detectors, according to one or
more embodiments of the invention. The system includes an optional
reference FBAR detector 1862, a splitter 1778, four chemically
functionalized FBAR detectors 1864A-D that each have one of four
corresponding different chemically functionalized electrode
surfaces 1865A-D, four mixers 1866A-D, four low pass filters
1868A-D, and four frequency counters 1870A-D.
[0102] As shown, the reference FBAR detector may be coupled with
the splitter. The splitter may split the signal representing the
reference resonance frequency into four corresponding signals. The
splitter is coupled with each of the four mixers and may provide
each of the four signals representing the reference resonance
frequency to one of the four mixers. In one or more embodiments,
the signals may be provided concurrently.
[0103] The four chemically functionalized FBAR detectors are each
coupled with one of the four mixers. For example, a first FBAR
detector 1864A is coupled with a first mixer 1866A, a second FBAR
detector 1864B is coupled with a second mixer 1866B, and so on. The
four differently chemically functionalized FBAR detectors may each
provide a signal representing a corresponding resonance frequency
to one of the four mixers. In one or more embodiments, the signals
may be provided concurrently.
[0104] The four mixers may each compare the signals, such as, for
example, as described above. The four mixers are each coupled with
one of the four low pass filters and may provide comparison
information to the filters.
[0105] The four low pass filters may filter the comparison
information, such as, for example, as described above. The four low
pass filters are each coupled with one of the four frequency
counters and may provide the filtered information to the frequency
counters.
[0106] Concurrent collection of signals may offer a potential
advantage of accumulating or strengthening a potentially weak
signal over time. This may potentially help to improve chemical
analysis.
[0107] Now, the scope of the invention is not limited to just the
above-described arrangements of FBAR detectors. Other arrangements
may include either fewer or more than four chemically
functionalized FBAR detectors. By way of example, two, five, ten,
twenty, or more chemically functionalized FBAR detectors may
optionally be included. Still other arrangements may lack the
reference FBAR detector. Yet other arrangements may include some
FBAR detectors in sequential arrangement and others in concurrent
arrangement, etc.
[0108] By now it should be appreciate that many different types of
samples and chemical species may be analyzed by the chemical
analysis systems disclosed herein. In one or more embodiments of
the invention, the sample may include a gas, although the scope of
the invention is not limited in this respect. For example, the
sample may include air, an ambient gas, a carrier gas, or another
gas. The sample may at least potentially include one or more
chemical species of interest. Suitable chemical species of interest
include, but are not limited to, hazardous chemicals and biological
molecules. Examples of suitable hazardous chemicals include, but
are not limited to, warefare agents, explosives, pollutants, radon,
and carbon dioxide, to name just a few examples. Examples of
suitable biological molecules include, but are not limited to,
proteins, nucleic acid derivatives (for example nucleic acids,
nucleic acid fragments, nucleotides, nucleosides (e.g. adenosine,
cytidine, guanosine, thymidine, uridine), bases (e.g. adenine,
cytosine, guanine, thymine, uracil), purine, pyrimidine, biological
sugars, and the like. Other suitable chemical species of interest
include, but are not limited to, water, ammonia, chloroform, and
the like. These are just examples of the types of samples and
chemical species that may be analyzed.
VIII. Systems Including Chemical Analysis Systems
[0109] FIG. 19 shows a chemical analysis system 1901 in which a
monolithically integrated chemical analysis system 1900 may be
employed, according to one or more embodiments of the invention.
The chemical analysis system 1901 includes an optional filter 1910,
a valve 1920 having an inlet that is coupled with an outlet of the
filter, the monolithically integrated chemical analysis system
having an inlet that is coupled with an outlet of the valve, and a
pump having an inlet that is coupled with an outlet of the
monolithically integrated chemical analysis system. The scope of
the invention is not limited to this particular connection of the
monolithically integrated chemical analysis system 1900 with the
other components. Other arrangements of valves (or other fluid flow
regulation devices), and pumps (or fans or other devices to cause
flow) are also contemplated. The monolithically integrated chemical
analysis system includes an optional chemical accumulator 1952, a
chromatograph 1954, and one or more FBAR detectors 1956, which may
each have attributes as described elsewhere herein.
[0110] A representative method of use, according to one or more
embodiments of the invention, may include opening the valve,
activating the pump in order to pump gas through the filter,
through the opened valve, and into the chemical accumulator. The
gas introduced into the chemical accumulator may potentially
include one or more chemical species that may be accumulated in the
chemical accumulator. After a sufficient amount of accumulation,
the valve may be closed, a heater may heat the chemical
accumulation material to release the accumulated chemical species,
and the chromatograph and FBAR detector may process the species as
described above. The gas including any analyzed chemical species
may be discharged from the pump, such as, for example, to
atmosphere or another suitable destination.
[0111] FIG. 20 shows a container 2000 having a chemical analysis
system 2010 and a gas 2020 sealed or otherwise included therein,
according to one or more embodiments of the invention. Suitable
containers include, but are not limited to, pressurized gas
cylinders, fire extinguishers, commercial packages, pill bottles,
and hazardous materials containers.
[0112] In one or more embodiments of the invention, the chemical
analysis system may be used to detect a change in composition
and/or pressure of the gas in the container based at least in part
on a detected change in resonance frequency. For example, the
chemical analysis system may detect entry of a foreign or ambient
chemical species, such as, for example, air, oxygen, or nitrogen,
into the container. As another example, the chemical analysis
system may detect a reduction in concentration and/or pressure of a
native chemical species in the container. Such detection may be
used, for example, to detect and infer damage to the container,
tampering with the container, and the like. The chemical analysis
system may include one or more FBAR detectors and need not include
either a chemical accumulator or a chromatograph, as these
components are not required in this application.
[0113] As shown, in one or more embodiments of the invention, an
optional notification device 2030 may be included outside the
chamber and coupled with the chemical analysis system to provide a
notification signal based on the chemical analysis, such as, for
example, if a great enough change in resonance frequency is
detected. One type of suitable notification device includes a
speaker or other audible notification device. Another type of
suitable notification device includes a light or other visual
notification devices. Still another type of suitable notification
device is includes both an audible and visual notification device.
Yet another type of suitable notification device includes a
wireless transmitter or transceiver to wirelessly transmit and/or
receive information, such as, for example, to transmit chemical
analysis information.
[0114] FIG. 21 shows an electronic device 2100 including a chemical
analysis system 2110, according to one or more embodiments of the
invention. In one or more embodiments of the invention, the
electronic device may include a mobile and wireless electronic
device. Suitable mobile and wireless electronic devices include,
but are not limited to, laptop computers, personal digital
assistants, cellular phones, walkie-talkies, pagers, wireless
communication devices, vehicles with wireless capability and
potentially geographic positioning capability. Various other
electronic devices are also suitable, such as, for example, desktop
computers and watches, whether or not they are wireless or
mobile.
[0115] In one or more embodiments of the invention, the chemical
analysis system may be used to detect a chemical species in an
ambient gas 2120. The electronic device may optionally have a
notification device 2130 to notify the user based on the chemical
analysis. Suitable notification devices include, but are not
limited to, the notification devices mentioned above. In one
aspect, alerts or other chemical analysis results may be displayed
on a screen, provided by a speaker, or the like. In an aspect, the
chemical analysis system may couple with a wireless transmitter and
may transmit analysis information, such as, for example, an alert
signal.
[0116] The electronic device may also have a memory 2140. The
memory may provide a machine-accessible and/or readable medium that
may be used to store chemical analysis instructions, such as, for
example, fingerprint comparison instructions, data useful for
performing chemical analysis, such as, for example, predetermined
fingerprints, and chemical analysis result data. Certain electronic
devices may have static-RAM (SRAM), while other electronic devices
may have dynamic-RAM (DRAM), while still other electronic devices
may have a Flash memory. Other electronic devices may have other
types of memory known in the arts.
[0117] In one or more embodiments of the invention, the electronic
device having the chemical analysis system may be included in a
chemical sensor network. The network may include a plurality of
potentially different types of electronic devices that may report
chemical analysis results to a data collection center. Without
limitation on the scope of the present invention, the chemical
analysis results may be analyzed to determine the location and/or
the spread of hazardous chemicals, such as, for example,
pollutants, explosives, warefare agents, biological weapons, and
materials of mass destruction, or other chemical species of
interest.
[0118] According to one or more embodiments of the invention,
chemical analysis systems and/or electronic devices having chemical
analysis systems may be included in a manufacturing facility, such
as, for example, a semiconductor fabrication facility. Without
limitation, the chemical analysis systems may be used to detect
chemical species in the air and/or perform other environmental
monitoring or other functions known to be potentially useful in a
semiconductor fabrication facility
IX. Other Matters
[0119] In the description above, for the purposes of explanation,
numerous specific details have been set forth in order to provide a
thorough understanding of the embodiments of the invention. It will
be apparent however, to one skilled in the art, that one or more
other embodiments may be practiced without some of these specific
details. In other instances, well-known circuits, structures, and
devices, have been shown in block diagram form or without detail in
order to avoid obscuring the understanding of the description.
[0120] In addition, it is to be realized that the scope of the
invention is to encompass variations in size, materials, shape,
form, function and manner of operation, assembly and use, of the
embodiments and components of the invention as are deemed readily
apparent to one of ordinary skill in the art. All equivalents to
those illustrated in the drawings and described in the
specification are encompassed by the present invention. For
simplicity and/or to facilitate illustration, certain components
illustrated in the figures have not been drawn to scale and may
instead have been exaggerated.
[0121] In the description and claims, the terms "coupled" and
"connected," along with their derivatives, may be used. "Connected"
may be used to indicate that two or more elements are in direct
physical and/or electrical contact with each other. "Coupled" may
also mean that two or more elements are in direct physical and/or
electrical contact. However, "coupled" may also mean that two or
more elements are not in direct physical and/or electrical contact
with each other, but yet may still co-operate or interact with each
other, such as, for example, through one or more other components
or materials.
[0122] Various operations and methods have been described.
Operations may optionally be added to and/or removed from the
methods. Also, operations may optionally be performed in a
different order. Many modifications and adaptations to the methods
are contemplated. The particular embodiments described are not
provided to limit the invention but for purposes of illustration.
The scope of the invention is not to be determined by the specific
examples provided above but only by the claims below.
[0123] One or more embodiments of the invention may be provided as
a program product or other article of manufacture that may include
a machine-accessible and/or readable medium having stored thereon
one or more instructions and/or data structures, such as, for
example, chemical analysis instructions and/or predetermined
fingerprints and/or fingerprint comparison instructions. The medium
may provide instructions, which, if executed by a machine, may
result in and/or cause the machine to perform one or more of the
operations or methods disclosed herein. Suitable machines include,
but are not limited to, the electronic devices disclosed above and
various other devices with one or more processors. The medium may
include a mechanism that provides or stores information in a form
that is accessible by the machine. For example, the medium may
optionally include recordable and/or non-recordable mediums, such
as, for example, floppy diskette, optical storage medium, optical
disk, CD-ROM, magnetic disk, magneto-optical disk, read only memory
(ROM), programmable ROM (PROM), erasable-and-programmable ROM
(EPROM), electrically-erasable-and-programmable ROM (EEPROM),
random access memory (RAM), static-RAM (SRAM), dynamic-RAM (DRAM),
Flash memory, and combinations thereof.
[0124] For clarity, in the claims, any element that does not
explicitly state "means for" performing a specified function, or
"step for" performing a specified function, is not to be
interpreted as a "means" or "step" clause as specified in 35 U.S.C.
Section 112, Paragraph 6. In particular, any potential use of "step
of" in the claims herein is not intended to invoke the provisions
of 35 U.S.C. Section 112, Paragraph 6.
[0125] It should also be appreciated that reference throughout this
specification to "one embodiment", "an embodiment", or "one or more
embodiments", for example, means that a particular feature may be
included in the practice of the invention. Similarly, it should be
appreciated that in the description various features are sometimes
grouped together in a single embodiment, Figure, or description
thereof for the purpose of streamlining the disclosure and aiding
in the understanding of various inventive aspects. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that the invention requires more features than are
expressly recited in each claim. Rather, as the following claims
reflect, inventive aspects may lie in less than all features of a
single disclosed embodiment. Thus, the claims following the
Detailed Description are hereby expressly incorporated into this
Detailed Description, with each claim standing on its own as a
separate embodiment of the invention.
[0126] Accordingly, while the invention has been thoroughly
described in terms of several embodiments, those skilled in the art
will recognize that the invention is not limited to the particular
embodiments described, but may be practiced with modification and
alteration within the spirit and scope of the appended claims. The
description is thus to be regarded as illustrative instead of
limiting.
* * * * *