U.S. patent application number 12/117000 was filed with the patent office on 2009-11-12 for electrode arrays and methods of fabricating the same using printing plates to arrange particles in an array.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. Invention is credited to Tobias Kraus, Laurent Malaquin, Heiko Wolf.
Application Number | 20090278213 12/117000 |
Document ID | / |
Family ID | 41266179 |
Filed Date | 2009-11-12 |
United States Patent
Application |
20090278213 |
Kind Code |
A1 |
Kraus; Tobias ; et
al. |
November 12, 2009 |
ELECTRODE ARRAYS AND METHODS OF FABRICATING THE SAME USING PRINTING
PLATES TO ARRANGE PARTICLES IN AN ARRAY
Abstract
Electrode arrays and methods of fabricating the same using a
printing plate to arrange conductive particles in alignment with an
array of electrodes are provided. In one embodiment, a
semiconductor device comprises: a semiconductor topography
comprising an array of electrodes disposed upon a semiconductor
substrate; a dielectric layer residing upon the semiconductor
topography; and at least one conductive particle disposed in or on
the dielectric layer in alignment with at least one of the array of
electrodes.
Inventors: |
Kraus; Tobias;
(Saarbruecken, DE) ; Malaquin; Laurent; (Linas,
FR) ; Wolf; Heiko; (Pfaeffikon, CH) |
Correspondence
Address: |
Cantor Colburn LLP-IBM Europe
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
41266179 |
Appl. No.: |
12/117000 |
Filed: |
May 8, 2008 |
Current U.S.
Class: |
257/414 ;
257/E21.158; 257/E29.111; 438/674 |
Current CPC
Class: |
H01L 2224/13157
20130101; H01L 2224/13181 20130101; H01L 2224/13186 20130101; H01L
2224/13184 20130101; H01L 2224/13155 20130101; H01L 2224/13164
20130101; H01L 2224/13169 20130101; H01L 2224/0362 20130101; H01L
2224/13144 20130101; G01N 33/54366 20130101; H01L 2224/13178
20130101; H01L 2924/01077 20130101; H01L 2224/0401 20130101; H01L
2224/119 20130101; H01L 2224/13124 20130101; H01L 2224/13147
20130101; H01L 2224/13157 20130101; H01L 2224/13164 20130101; H01L
2224/11003 20130101; H01L 2224/13178 20130101; H01L 2224/11334
20130101; H01L 2224/13184 20130101; H01L 24/11 20130101; H01L
2224/16 20130101; H01L 2924/0102 20130101; H01L 2224/0362 20130101;
H01L 2224/05567 20130101; H01L 2224/119 20130101; H01L 2924/01079
20130101; H01L 2224/13139 20130101; H01L 2224/13144 20130101; H01L
2924/01078 20130101; H01L 2924/01019 20130101; H01L 2224/13124
20130101; H01L 2224/13022 20130101; H01L 2224/13155 20130101; H01L
2224/13181 20130101; H01L 2224/13186 20130101; H01L 2224/05554
20130101; H01L 2224/13139 20130101; H01L 2224/13147 20130101; H01L
24/13 20130101; H01L 2924/01046 20130101; H01L 2924/00014 20130101;
H01L 2924/00014 20130101; H01L 2924/00014 20130101; H01L 2924/00014
20130101; H01L 2224/13169 20130101; H01L 2924/00012 20130101; H01L
2924/00014 20130101; H01L 2924/053 20130101; H01L 2924/00014
20130101; H01L 2924/00014 20130101; H01L 2924/00014 20130101; H01L
2924/00014 20130101; H01L 2924/01049 20130101; H01L 2924/00014
20130101; H01L 2924/00014 20130101; H01L 2924/0105 20130101; H01L
2924/00014 20130101 |
Class at
Publication: |
257/414 ;
438/674; 257/E29.111; 257/E21.158 |
International
Class: |
H01L 29/40 20060101
H01L029/40; H01L 21/28 20060101 H01L021/28 |
Claims
1. A semiconductor device comprising: a semiconductor topography
comprising an array of electrodes disposed upon a semiconductor
substrate; a dielectric layer residing upon the semiconductor
topography; and at least one conductive particle disposed in or on
the dielectric layer in alignment with at least one of the array of
electrodes.
2. The semiconductor device of claim 1, wherein the at least one
conductive particle has a grain size dimension of less than or
equal to about 100 micrometers.
3. The semiconductor device of claim 2, wherein the at least one
conductive particle has a grain size dimension of less than or
equal to about 100 nanometers
4. The semiconductor device of claim 1, wherein the at least one
conductive particle is a plurality of conductive particles in
alignment with and in electrical communication with the array of
electrodes.
5. The semiconductor device of claim 1, wherein the at least one
conductive particle comprises Cu, Au, Ag, Pt, Ir, W, Ta, Pd, Al,
Ni, Co, a conductive oxide, or a combination comprising at least
one of the foregoing.
6. The semiconductor device of claim 1, wherein the dielectric
layer has a substantially planar surface and comprises a
polymer.
7. The semiconductor device of claim 1, wherein the at least one
conductive particle is substantially cube shaped or spherical
shaped.
8. The semiconductor device of claim 1, wherein the at least one
conductive particle is functionalized with an inorganic ion, a
protein, an enzyme, a nucleic acid, a vitamin, an antibody, a
steroid, a hormone, an aminoacid, or a combination comprising at
least one of the foregoing.
9. The semiconductor device of claim 1, wherein each electrode in
the array of electrodes has a lateral dimension of less than or
equal to about 1000 micrometers.
10. A method of fabricating a semiconductor device, comprising:
contacting a face of a printing plate with a suspension comprising
conductive particles to arrange the particles at predefined
positions on the face of the printing plate; and contacting a
dielectric layer residing upon an array of electrodes disposed upon
a semiconductor substrate with the face of the printing plate to
transfer the conductive particles to a position in or on the
dielectric layer.
11. The method of claim 10, wherein the conductive particles have a
grain size dimension of less than or equal to about 100
micrometers.
12. The method of claim 10, wherein the conductive particles have a
grain size dimension of less than or equal to about 100
nanometers.
13. The method of claim 10, wherein the predefined positions on the
face of the printing plate comprise recessed features, protruding
structures, binding sites, or a combination comprising at least one
of the foregoing.
14. The method of claim 10, wherein the conductive particles are
aligned to the array of electrodes during said contacting of the
dielectric layer with the face of the printing plate.
15. The method of claim 10, wherein the conductive particles
comprises Cu, Au, Ag, Pt, Ir, W, Ta, Pd, Al, Ni, Co, a conductive
oxide, or a combination comprising at least one of the
foregoing.
16. The method of claim 10, wherein the conductive particles are
substantially cube shaped or spherical shaped.
17. The method of claim 10, wherein the dielectric layer comprises
a polymer.
18. The method of claim 10, wherein the dielectric layer is
planarized prior to being contacted with the face of the printing
plate.
19. The method of claim 10, wherein the conductive particles are
functionalized with an inorganic ion, a protein, an enzyme, a
nucleic acid, a vitamin, an antibody, a steroid, a hormone, an
aminoacid, or a combination comprising at least one of the
foregoing.
20. The method of claim 10, wherein each electrode in the array of
electrodes has a lateral dimension of less than or equal to about
1000 micrometers.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to semiconductor device fabrication,
and particularly to electrode arrays and methods of fabricating
such arrays using a printing plate to arrange conductive particles
in alignment with an array of electrodes.
[0003] 2. Description of Background
[0004] Substantial attention has been directed to the design,
implementation, and use of array-based electronic systems for
carrying out and/or monitoring biological systems. For example,
electronic biosensors of various types have been used to monitor
the progress of certain biological systems. Biosensors have been
described that include an array of electrode test sites in
electrical connection with a plurality of conductive leads. The
electrode test sites can be formed in a semiconductor wafer using
photolithography and etch processing techniques. Further, the test
sites can be coupled to associated detection circuitry via
transistor switches using row and column addressing techniques
employed, for example, in addressing dynamic random access memory
(DRAM) or active matrix liquid crystal display (AMLCD) devices.
[0005] There are ongoing efforts to increase the density of
electrode arrays by reducing electrode and overlying lead or
contact sizes to nanometer-or micrometer-scale dimensions, thereby
producing "microelectrode arrays" (MEAs). However, it has been
difficult to produce MEAs with very small dimensions using current
top-down semiconductor fabrication methods. For example, current
photolithography and etch techniques can be employed to pattern
openings or vias in an insulation layer formed above the electrodes
before filling those vias with a conductive material to form
contacts to the electrodes. However, the ability of the
photolithography and etch techniques to pattern small features is
restricted by factors such as the resolution limits of the optical
lithography system. It would therefore be desirable to develop a
method for producing a large number of electrode arrays of
relatively small dimensions at a relatively low cost.
SUMMARY OF THE INVENTION
[0006] The shortcomings of the prior art are overcome and
additional advantages are provided through the provision of
electrode arrays and methods of fabricating the same using a
printing plate to arrange conductive particles in alignment with an
array of electrodes. In one embodiment, a semiconductor device
comprises: a semiconductor topography comprising an array of
electrodes disposed upon a semiconductor substrate; a dielectric
layer residing upon the semiconductor topography; and at least one
conductive particle disposed in or on the dielectric layer in
alignment with at least one of the array of electrodes.
[0007] In another embodiment, a method of fabricating a
semiconductor device comprises: contacting a face of a printing
plate with a suspension comprising conductive particles to arrange
the particles at predefined positions on the face of the printing
plate; and contacting a dielectric layer residing upon an array of
electrodes disposed upon a semiconductor substrate with the face of
the printing plate to transfer the conductive particles to a
position in or on the dielectric layer.
[0008] Additional features and advantages are realized through the
techniques of the present invention. Other embodiments and aspects
of the invention are described in detail herein and are considered
a part of the claimed invention. For a better understanding of the
invention with advantages and features, refer to the description
and to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
objects, features, and advantages of the invention are apparent
from the following detailed description taken in conjunction with
the accompanying drawings in which:
[0010] FIGS. 1-3 illustrate one example of a semiconductor
fabrication method in which a printing plate is used to arrange
conductive particles in alignment with an array of electrodes
formed upon a semiconductor substrate and coated by a dielectric
layer; and
[0011] FIG. 4 illustrates one example of a semiconductor device
comprising conductive particles arranged in alignment with an
underlying array of electrodes.
[0012] The detailed description explains the preferred embodiments
of the invention, together with advantages and features, by way of
example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Turning now to the drawings in greater detail, it will be
seen that FIGS. 1-3 illustrate an exemplary embodiment of a method
for fabricating an array of electrodes comprising conductive
particles printed in alignment with an array of flat electrodes
formed above a semiconductor substrate using, for example, a
directed assembly method. This method can be used to economically
form an array of densely packed electrodes across a large area in a
relatively short period of time. The electrode arrays described
herein can be interfaced with biological systems.
[0014] As shown in FIG. 1, an array of electrodes can be fabricated
by obtaining a printing plate 10 that includes an array of recessed
features 12 on the face of the printing plate 10. The printing
plate 10 can include a molded material that can replicate a
three-dimensional relief structure by a molding process. Examples
of suitable molded materials include but are not limited to as
silicone, elastomers that can replicate a three-dimensional relief
structure by a molding process (e.g. fluorinated polyethers), or
combinations comprising at least one of the foregoing. The recessed
features 12 of the printing plate 10 can be pre-selected to
correspond with an array of flat electrodes formed upon a
semiconductor substrate (discussed later). A suspension 14
comprising conductive particles 16 dispersed therein can be placed
in contact with the face of the printing plate 10. As the
suspension 14 is moved over the printing plate 10, e.g., on a
movable stage, a particle 16 becomes embedded in each recessed
feature 12 of the printing plate 10, as depicted in FIG. 1. In this
manner, the conductive particles 16 are purposely arranged in the
array of recessed features 12. When the particles 16 have assumed
their desired positions, the liquid can be removed to form a dry,
filled printing plate 10 that can be stored until it is desirable
to transfer the particles 16 to a substrate. In another embodiment,
the particles can be captured in protruding structures on the
printing plate such as corners having 90.degree. angles. In yet
another embodiment, the particles can be captured on binding sites
on the printing plate having chemical functionalities that
specifically attract and bind the particles. Examples of such
chemical functionalities include but are not limited to
polyelectrolytes.
[0015] The particle suspension 14 shown in FIG. 1 can be formed by
mixing the conductive particles 16 with a liquid. Examples of
suitable liquids include but are not limited to ink, water, aqueous
solutions comprising surfactants, alcohols (e.g., methanol,
ethanol, propanol, and 2-propanol), and combinations comprising at
least one of the foregoing (e.g., a water/alcohol mixture). The
amount of particles present in the liquid can be about 0.01 to
about 40% by weight, specifically about 0.01 to about 20% by
weight, more specifically about 0.05 to about 10% by weight, and
even more specifically about 0.1 to about 5% by weight. Examples of
materials that can be present in the conductive particles 16
include but are not limited to metals (e.g., Cu, Au, Ag, Pt, Ir, W,
Ta, Pd, Al, Ni, and Co), conductive oxides such as indium tin oxide
(ITO), and combinations comprising at least one of the foregoing
metals. In one embodiment, the particles 16 have a grain size
dimension of less than or equal to about 100 micrometers (microns),
more specifically less than or equal to about 100 nanometers
(particles of this size are referred to as "nanoparticles"), to
allow for the formation of densely packed electrode arrays. The
term "grain size dimension" is herein defined as any straight lined
segment that passes through the center of the particle and has its
end points positioned at the surface of the particle. Although the
particles 16 are depicted as being substantially spherical shaped,
they can have other geometries such as cube shaped. Particles of
such small dimensions can be synthesized by the reduction of the
salts of the metals to be formed into particles.
[0016] Turning to FIG. 2, the particles 16 disposed in the recessed
features 12 of the printing plate 10 can be transferred to a
semiconductor topography comprising an array of flat electrodes 20
disposed upon a semiconductor substrate 18 and a dielectric layer
22 extending across the electrodes 20. The substrate 18 can
comprise, for example, single crystalline silicon. The flat
electrodes 20 can be formed into an array or matrix upon the
substrate 18 by depositing a conductive material, e.g., a
transition metal, across the substrate 18 and patterning the
conductive material using photolithography followed by an etch
technique such as a dry, plasma etch. In one embodiment, each
electrode 20 has lateral dimensions (e.g., the width and the depth)
of less than or equal to about 1000 micrometers, more specifically
less than or equal to about 100 nanometers, such that a
microelectrode array is formed. The dielectric layer 22 can be
formed through the deposition of a thin dielectric material, e.g.,
a spin-deposited polymer, followed by the planarization of the
surface of the dielectric material using, e.g., chemical mechanical
polishing (CMP). The resulting dielectric layer 22 can have a
substantially planar surface. Examples of suitable polymers for use
in the dielectric layer 22 include but are not limited to
polymethylmethacrylate (PMMA), polystyrene (PS), polyimide,
polyurethanes (PU), spin-on glass, and combinations comprising at
least one of the foregoing.
[0017] The transfer of the conductive particles 16 can be
accomplished by positioning the printing plate 10 upside down on
top of the dielectric layer 22 such that the particles 16 are
aligned to the underlying electrodes 20. As a result of this
positioning, the particles are "stamped" into the dielectric layer
22 to which they adhere due to their large surface interface. As
shown in FIG. 3, after the removal of the printing plate 10, the
conductive particles 16 remain in or on the dielectric layer 22 in
their pre-selected positions, i.e., in alignment with the
underlying array of electrodes 20. In this manner, a conductive
particle 16 is positioned above each electrode 20. In an
alternative embodiment, multiple particles could be printed on each
electrode 20. Subsequently, the substrate 18 and the dielectric
layer 22 can be heated above the glass transition temperature,
T.sub.g, of the dielectric material.
[0018] The resulting alignment of the conductive particles 16 with
the array of electrodes 20 is better illustrated in FIG. 4. In one
embodiment, the electrodes 20 can be spaced apart by equivalent
distances, thus forming an equidistantly spaced array. As a result
of the printing step, the particles 16 can protrude into the
dielectric layer 22, and the dielectric layer 22 can be
sufficiently thin to allow the particles 16 to be in electrical
communication with corresponding ones of the array of flat
electrodes 20. For example, a polymeric dielectric layer 22 can
have a thickness of about equivalent to or less than the grain size
dimension of the printed particles. In preferred embodiments, the
thickness of the dielectric layer 22 is less than the grain size
dimension of the printed particles, specifically less than about
0.75 times the grain size dimension of the printed particles, or
more specifically less than half the grain size dimension of the
printed particles. Consequently, the protruding parts of the
particles 16 can act as electrodes.
[0019] The conductive particles described above can be
functionalized with inorganic salts or ions such as calcium,
chloride, inorganic phosphorous, potassium, selenium, and sodium;
proteins such as poly-L-lysine, laminin, bilirubin, albumin,
insuline, hemoglobin, collagen, fibronectin, and fibrinogen;
enzymes such as alkaline phosphatase, lactate dehydrogenase, and
glutamate oxalacetate transaminase; carbohydrates such as glucose;
lipids such as triglycerides nucleic acids, e.g., DNA, RNA, m-RNA,
t-RNA, or selected portions thereof; vitamins such as
beta-carotene, bioflavonoids, biotin, choline, CoQ-10, essential
fatty acids, folic acid, hesperidin, inositol, para-aminobenzoic
acid, rutin, vitamin A, vitamin B complex, vitamin B-1 thiamine,
vitamin B-2 riboflavin, vitamin B-3 niacin/niacinamide, vitamin B-5
pantothenic acid, vitamin B-6 pyridoxine, vitamin B-9 folic acid,
vitamin B-12 cyanocobalamine, vitamin B-15 dimethylglycine, vitamin
B-17 leatrile or amygdalin, vitamin C, vitamin D, vitamin E,
vitamin F unsaturated fats, vitamin G, vitamin J, vitamin K, and
vitamin P; antibodies such as immunoglobulin A, immunoglobulin D,
immunoglobulin E, immunoglobulin G, and immunoglobulin M; steroids
and hormones such as cholesterol, cortisol, follicle stimulating
hormone, growth hormone, leutinizing hormone, platelet-derived
growth factor, fibroblast growth factor, parathyroid hormone,
progesterone, prolactin, prostaglandins, testosterone, and thyroid
stimulating hormone; aminoacids such as alanine, arginine,
asparagine, aspartic acid, cysteine, glutamine, glutamic acid,
glycine, histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, proline, serine, threonine, tryptophan, and valine;
and aminoacid derivatives such as creatine.
[0020] In one embodiment, chemical functionalization of the
particles is achieved by pre-treating the surface of the particles
with a solution of a chemical moiety (e.g., proteins such as
poly-L-lysine and larninin) in water for a duration of, for
example, 2 hours. In another embodiment, the particles are treated
after they have been printed into the dielectric layer 22.
[0021] As used herein, the terms "a" and "an" do not denote a
limitation of quantity but rather denote the presence of at least
one of the referenced items. Moreover, ranges directed to the same
component or property are inclusive of the endpoints given for
those ranges (e.g., "about 5 wt % to about 20 wt %," is inclusive
of the endpoints and all intermediate values of the range of about
5 wt % to about 20 wt %). Reference throughout the specification to
"one embodiment", "another embodiment", "an embodiment", and so
forth means that a particular element (e.g., feature, structure,
and/or characteristic) described in connection with the embodiment
is included in at least one embodiment described herein, and might
or might not be present in other embodiments. In addition, it is to
be understood that the described elements may be combined in any
suitable manner in the various embodiments. Unless defined
otherwise, technical and scientific terms used herein have the same
meaning as is commonly understood by one of skill in the art to
which this invention belongs.
[0022] While the preferred embodiment to the invention has been
described, it will be understood that those skilled in the art,
both now and in the future, may make various improvements and
enhancements which fall within the scope of the claims which
follow. These claims should be construed to maintain the proper
protection for the invention first described.
* * * * *