U.S. patent application number 16/578751 was filed with the patent office on 2020-03-26 for methods for increasing adhesion between metallic films and glass surfaces and articles made therefrom.
The applicant listed for this patent is Corning Incorporated. Invention is credited to Dana Craig Bookbinder, Yunfeng Gu, Prantik Mazumder, Rajesh Vaddi.
Application Number | 20200095684 16/578751 |
Document ID | / |
Family ID | 68052016 |
Filed Date | 2020-03-26 |
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United States Patent
Application |
20200095684 |
Kind Code |
A1 |
Bookbinder; Dana Craig ; et
al. |
March 26, 2020 |
METHODS FOR INCREASING ADHESION BETWEEN METALLIC FILMS AND GLASS
SURFACES AND ARTICLES MADE THEREFROM
Abstract
Methods of plating a metal on a substrate including coating a
nanoporous metal-oxide layer on a surface of the substrate prior to
metal plating. Methods may include coating a surface of the
substrate with a slurry including colloidal metal-oxide precursor
particles and aluminum oxide particles. After coating, the slurry
may be calcinated on the surface of the substrate to form a
nanoporous metal-oxide layer on the surface. Then, a metallic film
may be plated on the nanoporous metal-oxide layer. The metallic
film may be plated by an electroless plating method and/or an
electroplating method. Articles, such as electronic interposers,
may be made using the methods of plating a metal described
herein.
Inventors: |
Bookbinder; Dana Craig;
(Corning, NY) ; Gu; Yunfeng; (Painted Post,
NY) ; Mazumder; Prantik; (Ithaca, NY) ; Vaddi;
Rajesh; (Corning, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Corning Incorporated |
Corning |
NY |
US |
|
|
Family ID: |
68052016 |
Appl. No.: |
16/578751 |
Filed: |
September 23, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62735519 |
Sep 24, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C03C 17/25 20130101;
C23C 18/1633 20130101; C03C 17/3649 20130101; C03C 17/36 20130101;
C23C 18/165 20130101; C23C 18/1653 20130101; C03C 17/3618 20130101;
C23C 18/127 20130101; C23C 18/1893 20130101; C25D 5/54 20130101;
C25D 3/38 20130101; C25D 7/123 20130101; C23C 18/38 20130101; C23C
18/1216 20130101; C03C 17/3697 20130101; C03C 2217/425
20130101 |
International
Class: |
C23C 18/16 20060101
C23C018/16; C25D 3/38 20060101 C25D003/38; C25D 5/54 20060101
C25D005/54; C23C 18/38 20060101 C23C018/38 |
Claims
1. A method of plating a metal on a substrate, the method
comprising: coating a surface of the substrate with a slurry, the
slurry comprising: colloidal metal-oxide precursor particles, and
aluminum oxide particles; calcinating the slurry on the surface of
the substrate to form a nanoporous metal-oxide layer on the surface
of the substrate; and plating the nanoporous metal-oxide layer with
a metal.
2. The method of claim 1, wherein the colloidal metal-oxide
precursor particles comprise at least one of: aluminum oxide
precursor particles, silicon oxide precursor particles, titanium
oxide precursor particles, cerium oxide precursor particles, and
zirconium oxide precursor particles.
3. The method of claim 1, wherein the colloidal metal-oxide
precursor particles comprise aluminum oxide precursor
particles.
4. The method of claim 1, wherein the colloidal metal-oxide
precursor particles comprise aluminum oxide hydroxide
particles.
5. The method of claim 1, wherein the metal comprises copper.
6. The method of claim 1, wherein the substrate is a glass or
glass-ceramic substrate.
7. The method of claim 1, wherein the substrate is a glass or
glass-ceramic substrate comprising a via formed in the substrate
and wherein the surface is an interior surface of the via.
8. The method of claim 7, wherein the via is a through via.
9. The method of claim 1, wherein the nanoporous metal-oxide layer
comprises an average pore size in the range of 5 nanometers to 30
nanometers.
10. The method of claim 1, wherein the nanoporous metal-oxide layer
comprises a pore volume in the range of 0.3 cubic centimeters per
gram to 10 cubic centimeters per gram.
11. The method of claim 1, wherein the aluminum oxide particles
comprise nanoparticles.
12. The method of claim 1, wherein the slurry comprises X wt %
aluminum oxide particles and Y wt % colloidal metal-oxide precursor
particles, and wherein X is greater than or equal to Y.
13. The method of claim 1, wherein a weight percent ratio of the
aluminum oxide particles to the colloidal metal-oxide precursor
particles in the slurry is in the range of 3:1 to 20:1.
14. The method of claim 1, wherein plating the nanoporous
metal-oxide layer comprises an electroless plating method.
15. The method of claim 14, wherein plating the nanoporous
metal-oxide layer further comprises an electroplating method
performed after the electroless plating method.
16. The method of claim 1, wherein the plated metal is capable of
passing a 3N/cm tape test after being annealed at 350 degrees C.
for 30 minutes.
17. A method of plating copper on a substrate, the method
comprising: coating a surface of the substrate with a slurry, the
slurry comprising: colloidal aluminum oxide hydroxide particles,
and aluminum oxide particles; calcinating the slurry on the surface
of the substrate to form a nanoporous metal-oxide layer on the
surface of the substrate; charging the nanoporous metal-oxide
layer, wherein the charging comprises treating the nanoporous
metal-oxide layer with an aminosilane; and plating the nanoporous
metal-oxide layer with copper after charging the nanoporous
metal-oxide layer.
18. An article, comprising: a glass or glass-ceramic substrate
comprising a surface having a plurality of vias formed therein,
each via having an interior surface; a nanoporous metal-oxide layer
coated on the interior surface of each of the plurality of vias,
the nanoporous metal-oxide layer comprising aluminum oxide and an
average pore size in the range of 5 nanometers to 30 nanometers;
and a metal plating disposed on the nanoporous metal-oxide layer in
each of the plurality of vias.
19. The article of claim 18, wherein a least one of the vias is a
through via.
20. The article of claim 18, wherein the metal plating comprises
copper.
Description
[0001] This application claims the benefit of priority to U.S.
Provisional Application Ser. No. 62/735,519 filed on Sep. 24, 2018,
the content of which is relied upon and incorporated herein by
reference in its entirety.
FIELD
[0002] The present disclosure relates to methods for plating a
metallic film on a glass or glass-ceramic substrate. In particular,
the present disclosure relates to methods for plating a metallic
film on a glass or glass-ceramic substrate that include coating a
surface of the substrate with a nanoporous metal-oxide layer to
improve adhesion between the metallic film and the substrate.
BACKGROUND
[0003] Glass and glass-ceramic substrates have become an attractive
alternative to silicon and organic fiber-reinforced polymer
substrates for electronic applications. Glass and glass-ceramic
substrates with vias are desirable for many applications, including
interposers used as, for example, electrical interfaces, RF (radio
frequency) filters, and RF switches. For example, 3D interposers
with through package via (TPV) interconnects that connect a logic
device on one side and a memory on the other side are useful in
high bandwidth devices. Organic interposers suffer from poor
dimensional stability across different temperatures. Silicon wafers
are expensive and suffer from high dielectric loss due to their
semiconducting properties. There is a trend, therefore, toward the
use of glass or glass-ceramic as a superior substrate material due
to its low dielectric constant, thermal stability, and low
cost.
[0004] To create desired electrical properties, a glass or
glass-ceramic substrate may be coated with a metallic material like
copper. In case of interposers, the vias may be filled with a
metallic material like copper. But metallic materials like copper
do not adhere well to a glass or glass-ceramic material. A hermetic
seal between copper and glass is desired for some applications, and
such a seal is difficult to obtain because of the poor adhesion
between metallic materials and glass or glass ceramic
materials.
[0005] Therefore, a continuing need exists for innovations in
methods for adhering a metallic film, such a copper film, to glass
and glass ceramic substrates.
BRIEF SUMMARY
[0006] The present disclosure is directed to methods of increasing
the effective adhesion between a metallic material, such as copper,
and a glass or glass ceramic substrate. The metallic material may
be electrolessly plated and/or electroplated on a planar surface of
a glass or glass-ceramic substrate, inside vias formed in the
substrate, or both. Suitable adhesion between the plated metallic
material and the glass or glass-ceramic substrate may be achieved
by forming a nanoporous metal-oxide layer on the substrate by
calcinating a slurry including metal-oxide particles and
metal-oxide precursor articles. Subsequent electroless plating
and/or electroplating of a metallic material on this nanoporous
metal-oxide layer leads to strong and effective adhesion between
the metallic material and the glass or glass-ceramic substrate due
to penetration of the metallic material into the interior of the
nanopores of the metal-oxide layer.
[0007] In a first aspect, a method of plating a metal on a
substrate is described, the method including coating a surface of
the substrate with a slurry including colloidal metal-oxide
precursor particles and aluminum oxide particles; calcinating the
slurry on the surface of the substrate to form a nanoporous
metal-oxide layer on the surface of the substrate; and plating the
nanoporous metal-oxide layer with a metal.
[0008] In a second aspect, the method of plating a metal substrate
according to aspects of the preceding paragraph may include
colloidal metal-oxide precursor particles that include at least one
of: aluminum oxide precursor particles, silicon oxide precursor
particles, titanium oxide precursor particles, cerium oxide
precursor particles, and zirconium oxide precursor particles.
[0009] In a third aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
colloidal metal-oxide precursor particles that include aluminum
oxide precursor particles.
[0010] In a fourth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
colloidal metal-oxide precursor particles that include aluminum
oxide hydroxide particles.
[0011] In a fifth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
plating the nanoporous metal-oxide layer with a metal including
copper.
[0012] In a sixth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
a substrate that is a glass or glass-ceramic substrate.
[0013] In a seventh aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
a substrate that is a glass or glass-ceramic substrate having a via
formed in the substrate and the surface of the substrate on which
the nanoporous metal-oxide layer is formed may include an interior
surface of the via. In some embodiments, the via may be a through
via.
[0014] In an eighth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
a nanoporous metal-oxide layer having an average pore size in the
range of 5 nanometers to 30 nanometers.
[0015] In a ninth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
a nanoporous metal-oxide layer having a pore volume in the range of
0.3 cubic centimeters per gram to 10 cubic centimeters per
gram.
[0016] In a tenth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
aluminum oxide particles that include nanoparticles.
[0017] In an eleventh aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include aluminum oxide particles having an average particle
size in the range of 10 nanometers to 100 nanometers.
[0018] In a twelfth aspect, the method of plating a metal substrate
according to aspects of any of the preceding paragraphs may include
colloidal metal-oxide precursor particles having an average
particle size in the range of 60 nanometers to 90 nanometers.
[0019] In a thirteenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include aluminum oxide particles having an average particle
size and colloidal metal-oxide precursor particles having an
average particle size, where the average particle size of the
colloidal metal-oxide precursor particles is less than the average
particle size of the aluminum oxide particles.
[0020] In a fourteenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include aluminum oxide particles having an average particle
size and colloidal metal-oxide precursor particles having an
average particle size, where the average particle size of the
colloidal metal-oxide precursor particles is greater than the
average particle size of the aluminum oxide particles.
[0021] In a fifteenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include a slurry having X wt % aluminum oxide particles and Y
wt % colloidal metal-oxide precursor particles, where X is greater
than or equal to Y.
[0022] In a sixteenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include a slurry where a weight percent ratio of the aluminum
oxide particles to the colloidal metal-oxide precursor particles in
the slurry is in the range of 3:1 to 20:1. In some embodiments, the
weight percent ratio may be in the range of 3:1 to 10:1.
[0023] In a seventeenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include calcinating the slurry on the surface of the substrate
by heating the slurry to a calcination temperature in the range of
300 degrees C. to 650 degrees C.
[0024] In a eighteenth aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include plating the nanoporous metal-oxide layer with an
electroless plating method.
[0025] In an nineteenth aspect, the method of plating a metal
substrate according to aspects of the preceding paragraph may
include charging the nanoporous metal-oxide layer prior to the
electroless plating method. In some embodiments, charging the
nanoporous metal-oxide layer may include treating the nanoporous
metal-oxide layer with an aminosilane. In some embodiments, the
aminosilane may include aminopropyltriethoxysilane.
[0026] In a twentieth aspect, the method of plating a metal
substrate according to aspects of the preceding paragraph may
include adsorbing palladium complexes into the nanoporous
metal-oxide layer after charging the nanoporous metal-oxide layer
and prior to the electroless plating method.
[0027] In a twenty-first aspect, the method of plating a metal
substrate according to aspects of either of the two preceding
paragraphs may include plating the nanoporous metal-oxide layer
with an electroplating method performed after the electroless
plating method.
[0028] In a twenty-second aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include a plated metal that is capable of passing a 3N/cm tape
test after being annealed at 350 degrees C. for 30 minutes.
[0029] In a twenty-third aspect, the method of plating a metal
substrate according to aspects of any of the preceding paragraphs
may include a slurry including a pore former. In some embodiments,
the pore former may include polyethylene glycol.
[0030] In a twenty-fourth aspect, a metal plated substrate made by
the method according to aspects of any of the preceding paragraphs
is described.
[0031] In a twenty-fifth aspect, a method of plating copper on a
substrate is described, the method including coating a surface of
the substrate with a slurry including colloidal aluminum oxide
hydroxide particles and aluminum oxide particles; calcinating the
slurry on the surface of the substrate to form a nanoporous
metal-oxide layer on the surface of the substrate; charging the
nanoporous metal-oxide layer, where the charging includes treating
the nanoporous metal-oxide layer with an aminosilane; and plating
the nanoporous metal-oxide layer with copper after charging the
nanoporous metal-oxide layer.
[0032] In a twenty-sixth aspect, an article is described, the
article including a glass or glass-ceramic substrate including a
surface having a plurality of vias formed therein, each via having
an interior surface; a nanoporous metal-oxide layer coated on the
interior surface of each of the plurality of vias, the nanoporous
metal-oxide layer including aluminum oxide and an average pore size
in the range of 5 nanometers to 30 nanometers; and a metal plating
disposed on the nanoporous metal-oxide layer in each of the
plurality of vias.
[0033] In a twenty-seventh aspect, the article according to aspects
of the preceding paragraph may include at least one via that is a
through via.
[0034] In a twenty-eighth aspect, the article according to aspects
of either of the two preceding paragraphs may include a metal
plating that includes copper.
[0035] In a twenty-ninth aspect, the article according to aspects
of any of the three preceding paragraphs may include metal plating
that fills each of the plurality of the vias.
[0036] In a thirtieth aspect, the article according to aspects of
any of the four preceding paragraphs may include a nanoporous
metal-oxide layer that is coated on at least a portion of the
surface of the glass or glass-ceramic substrate.
[0037] In a thirty-first aspect, the article according to aspects
of the preceding paragraph may include a metal plating that is
disposed on the nanoporous metal-oxide layer coated on the surface
of the glass or glass-ceramic substrate. In some embodiments, the
metal plating disposed on the nanoporous metal-oxide layer coated
on the surface of the glass or glass ceramic substrate may be
capable of passing a 3N/cm tape test after being annealed at 350
degrees C. for 30 minutes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The accompanying figures, which are incorporated herein,
form part of the specification and illustrate embodiments of the
present disclosure. Together with the description, the figures
further serve to explain the principles of and to enable a person
skilled in the relevant art(s) to make and use the disclosed
embodiments. These figures are intended to be illustrative, not
limiting. Although the disclosure is generally described in the
context of these embodiments, it should be understood that it is
not intended to limit the scope of the disclosure to these
particular embodiments. In the drawings, like reference numbers
indicate identical or functionally similar elements.
[0039] FIG. 1 shows a substrate having through vias according to
some embodiments.
[0040] FIG. 2 shows a substrate having blind vias according to some
embodiments.
[0041] FIG. 3 shows a flowchart of a method for depositing a
metallic layer on a surface according to some embodiments.
[0042] FIGS. 4A-4C show a region of the substrate of FIG. 1 as it
appears at different process steps of the flow chart of FIG. 3.
[0043] FIGS. 5A and 5B show mechanical interlocking of palladium
catalyst and electroless copper according to some embodiments.
[0044] FIG. 6 shows an article according to some embodiments.
[0045] FIG. 7 shows scanning electron microscope images of a
spin-coated alumina AL20 coating.
[0046] FIGS. 8A and 8B show scanning electron microscope images of
an AL20 alumina coating.
[0047] FIG. 9 shows a graph of particle size distribution for two
slurries according to some embodiments.
[0048] FIGS. 10A and 10B show scanning electron microscope images
of a nanoporous aluminum oxide coating according to some
embodiments.
[0049] FIG. 11 shows a photograph of electroless copper formed on a
glass substrate coated with an AL20 alumina coating.
[0050] FIG. 12 shows a photograph of three samples with electroless
copper plated on a glass substrate coated with an AL20 alumina
coating after a 3N/cm tape test performed prior to annealing of the
samples.
[0051] FIG. 13 shows a photograph of three samples with electroless
copper plated on a glass substrate coated with an AL20 alumina
coating after a 3N/cm tape test performed after annealing of the
samples at 350 degrees C.
[0052] FIGS. 14A and 14B show scanning electron microscope images
of an AL20 alumina coating on a glass substrate after a 3N/cm tape
test performed after annealing of the samples at 350 degrees C.
[0053] FIG. 15 shows a photograph of three samples of electroless
copper plated on a glass substrate coated with a nanoporous
aluminum oxide layer according to some embodiments.
[0054] FIG. 16 shows a photograph of the three samples of FIG. 15
with electroplated copper deposited over the electroless copper
according to some embodiments.
[0055] FIG. 17 shows a scanning electron microscope image of an
electroplated copper film deposited on an electroless copper film
according to some embodiments.
[0056] FIGS. 18A and 18B show scanning electron microscope images
of electroless and electroplated copper deposited on a nanoporous
aluminum oxide layer according to some embodiments.
[0057] FIG. 19A shows a TEM/EDX image of a cross-section of a
substrate coated with a nanoporous aluminum oxide layer and plated
with copper according to some embodiments. FIG. 19B shows the
palladium content in the image of FIG. 19A. FIG. 19C shows the
copper content in the image of FIG. 19A. FIG. 19D shows the
aluminum content in the image of FIG. 19A. FIG. 19E shows the
silicon content in the image of FIG. 19A.
DETAILED DESCRIPTION
[0058] The following examples are illustrative, but not limiting,
of the present disclosure. Other suitable modifications and
adaptations of the variety of conditions and parameters normally
encountered in the field, and which would be apparent to those
skilled in the art, are within the spirit and scope of the
disclosure.
[0059] Glass and glass ceramic substrates with vias are desirable
for a number of applications. These vias typically need to be fully
or conformally filled with conducting metallic materials, such as
copper, to provide an electrical pathway through and/or within the
substrate. The chemical inertness and low intrinsic roughness of
glass and glass-ceramic materials, however, results in poor
adhesion between a metallic material and the glass or glass-ceramic
materials on surfaces of a glass or glass-ceramic substrate. For
example, the chemical internes and low intrinsic roughness may
result in poor adhesion between a metallic material and interior
surfaces of vias. Also, lack of adhesion between a metallic
material and a glass or glass-ceramic substrate could lead to
reliability issues such as cracking, delamination, and a path for
moisture and other contaminants along the glass-metal interface.
These reliability issues can result in undesirable electrical
properties.
[0060] Described herein are methods to improve metallization of a
glass or glass-ceramic substrate. In particular, described herein
are methods to improve the effective adhesion between a metallic
material, such as copper, and glass or glass-ceramic materials
defining a surface of a substrate, including interior surfaces of
vias. Improved effective adhesion between a metallic material and a
glass or glass-ceramic, both inside vias and on other surfaces of a
glass or glass-ceramic substrate, may be achieved with a nanoporous
metal-oxide interlayer. This nanoporous metal-oxide interlayer may
be a nanoporous aluminum oxide (alumina, Al.sub.2O.sub.3)
interlayer.
[0061] Nanoporous metal-oxide interlayers according to embodiments
of the present application may increase the adhesion of a metallic
material to a glass or glass-ceramic surface by creating a
mechanical interlock between the glass or glass-ceramic surface and
a plated metallic material. In particular, the nanoporous structure
of the metal-oxide interlayer with re-entrant geometries serves to
create a mechanical interlock between the plated metallic material
and the glass or glass-ceramic substrate. By creating nanoporous
structures having desirable pore structures, a high degree of
interlocking can be achieved, which results in strong adhesion
between a plated metallic material and a glass or glass-ceramic
surface.
[0062] The nanoporous interlayer may be made by coating all or a
portion of a glass or glass-ceramic substrate with a slurry
including colloidal metal-oxide precursor particles and metal-oxide
particles (e.g., alumina particles) followed by calcination at a
high temperature. These coating and calcination processes create
sufficient adhesion between the nanoporous interlayer and the
substrate. In some embodiments, the metal-oxide particles may be
nanoparticles.
[0063] The combination of colloidal metal-oxide precursor particles
and metal-oxide particles within a slurry creates a desired pore
structure for the nanoporous interlayer. Mixtures of these two
components in the slurry allow for the formation of desirable pore
sizes, pore volumes, and/or pore geometries in the nanoporous
interlayer. Appropriately controlled pore sizes, pore volumes,
and/or pore geometries leads to suitable adhesion and interlocking
between a glass or glass-ceramic material and a plated metallic
material. In some embodiments, the plated metallic material may be
adhered to the glass or glass-ceramic substrate such that plated
metallic material is capable of passing a 3N/cm tape test after
being annealing at 350 degrees C. for 30 minutes.
[0064] As described and referred to herein, a "3N/cm tape test" is
conducted according to ASTM 3359 using a tape having a specific
adhesion strength of 3 N/cm when bonded to a conductive metal that
is copper.
[0065] As used herein, "nanoporous" means a porous material having
an average pore size in the range of 1 nanometer (nm) to 100
nanometers. A nanoporous structure includes a plurality of
interconnected tunnels or "nanopores." The nanoporous structures
described herein are generally open structures, meaning that there
is a path of travel from anywhere within a nanopore to the surface
of the material. The nanoporous structures are open because of the
manner in which they are formed. While the nanoporous layers
described herein are generally interconnected, it is possible that
portions of the nanoporous network may be isolated from each
other.
[0066] The "size" of a nanopore is the average dimension of a
cross-section of the pore in a plane normal to the direction of the
pore. So, if a cylindrical nanopore intersects a surface, the
"size" of the nanopore is the diameter of the circle. For
non-circular cross-sections, the "size" of the cross-section is the
diameter of a circle having the same area as the cross-section. In
some embodiments, an average (mean) nanopore size may be measured
by obtaining a high-resolution scanning electron microscope (SEM)
image, measuring the area of all visible nanopores in a
100.times.100 nm area, calculating the diameter of a circle with
equivalent area for each visible nanopore, and calculating the
average of these diameters. Where the nanopores are circular in
shape, the same result may be obtained by directly measuring the
diameter of each nanopore. In some embodiments, an average (mean)
nanopore size may be measured by Barrett-Joyner-Halenda (BJH)
nitrogen adsorption and desorption. Unless indicated otherwise, an
average (mean) nanopore size discussed herein is measured by
Barrett-Joyner-Halenda (BJH) nitrogen adsorption and
desorption.
[0067] As used herein a "pore volume" is the ratio of a porous
material's open volume (volume occupied by pores, measured in cubic
centimeters (cc)) to the porous material's total mass (measured in
grams (g)). Unless indicated otherwise, a porous material's pore
volume discussed herein is measured by BJH nitrogen adsorption and
desorption.
[0068] As used herein, "nanoparticle" means a particle having at
least one dimension in the range of 1 nanometer to 100 nanometers
in size. The size of a nanoparticle may be measured by scanning
electron microscopy or a dynamic light scattering (DLS) particle
size analyzer. An average particle size of a batch of particles may
be measured by measuring a sample of the particles using scanning
electron microscopy or a DLS particle size analyzer, or may be
calculated from the Brunauer-Emmett-Teller (BET) surface area of
the sample. Unless indicated otherwise, the size of a nanoparticle
discussed herein is measured by scanning electron microscopy and an
average particle size of a batch of particles discussed herein is
calculated from the Brunauer-Emmett-Teller (BET) surface area of
the sample.
[0069] As used herein, a "colloidal" particle means a particle that
is dispersed and insoluble in a solution in which it mixed.
[0070] As used herein, "metal-oxide precursor particle" means a
particle that is a source particle for a metal-oxide particle. A
metal-oxide precursor particle is capable of undergoing a chemical
change that transforms it into a metal-oxide particle. The chemical
change may be induced by the application of energy, such as heat.
Exemplary metal-oxide precursor particles include oxide hydroxide
particles, oxide acetate particles, and oxide nitrate
particles.
[0071] As used herein, "slurry" means a mixture including a solvent
and particles that are insoluble in the solvent. The solvent may be
aqueous or non-aqueous.
[0072] As used herein, "calcination" or "calcinating" or
"calcinated" means the heating of a substance to high temperature
for the purpose of removing volatile ingredients and/or oxidizing
the substance.
[0073] As used herein, a "via" is an opening in a substrate. In
some embodiments, a via may extend all the way through the
substrate, in which case it is a "through via." In some
embodiments, a via may extend only partially through the substrate,
in which case it is a "blind via."
[0074] FIG. 1 shows a cross-section of an article 100 according to
some embodiments. Article 100 includes a substrate 110 having a
first surface 112, a second surface 114, and a thickness 116
measured from first surface 112 to second surface 114. One or more
vias 124 are formed in substrate 110 and extend from first surface
112 to second surface 114. Vias 124 are through vias. Each via 124
includes an interior surface 126 defining the shape of the via 124.
Vias 124 may have an internal dimension 128 in the range of 10
microns to 20 microns, for example.
[0075] Internal dimension 128 of vias 124 is defined by the
smallest lateral distance between opposing interior surfaces 126 on
a plane parallel to first surface 112. For example, for vias 124
with a circular cross-sectional shape, internal dimension 128 is
the diameter of the circle, for vias 124 with an elliptical
cross-sectional shape, internal dimension 128 is the diameter of
the ellipse along the ellipse's minor axis, and for vias 124 with a
square cross-sectional shape, internal dimension 128 is the width
or length of the square.
[0076] FIG. 2 shows a cross-section of an article 200 according to
some embodiments. Article 200 includes a substrate 110 having a
first surface 112, a second surface 114, and a thickness 116
measured from first surface 112 to second surface 114. One or more
vias 224 are formed in substrate 110 and extend from first surface
112 towards second surface 114 without reaching second surface 114.
Vias 224 are blind vias. Each via 224 includes an interior surface
226 defining the shape of the via 224. Vias 224 may have the same
cross-sectional shapes and sizes as vias 124. But since vias 224
are blind vias, interior surface 226 includes a closed bottom
surface 228 located between first surface 112 and second surface
114.
[0077] While FIGS. 1 and 2 show specific via configurations,
various other via configurations may be used. By way of
non-limiting example, vias having an hourglass shape, a barbell
shape, beveled edges, or a variety of other geometries may be used
instead of the cylindrical geometries shown in FIGS. 1 and 2. Vias
may be substantially cylindrical, for example having a waist (point
along the via with the smallest diameter) with a diameter that is
at least 70%, at least 75%, or at least 80% of the diameter of an
opening of the via on the first or second surface. Other via
geometries may be used. Vias may have any suitable aspect ratio.
For example, vias may have an aspect ratio of 1:1, 2:1, 3:1, 4:1,
5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any range having any two of these
values as endpoints, or any open-ended range having any of these
values as a lower bound. An aspect ratio for a via is the ratio of
substrate 110 thickness 116 to a via internal dimension 128.
[0078] In some embodiments, article 100 may be an interposer with
through-glass vias 124 and/or blind vias 224. These through-glass
vias 124 and/or blind vias 224 may be fabricated by any suitable
method. One method is to form a damage track in substrate 100 with
a laser, followed by etching. Exemplary methods are described in
U.S. Pat. No. 9,656,909, U.S. App. No. 62/588,615, and U.S. Pat.
App. Pub. No. 2015/0166395, each of which is incorporated herein by
reference in its entirety. Another method is to modify
photosensitive glass with a laser, followed by etching.
[0079] FIG. 3 shows a flowchart of a method 300 for plating a metal
on a substrate according to some embodiments. A method according to
embodiments of the present application may include all or some of
the steps shown in FIG. 3. Steps shown in method 300 are not
exhaustive; other steps can be performed before, after, or between
any of the described steps. In the following description, article
100 is used to illustrate the steps of method 300. However, method
300 may be applied to any article or substrate discussed herein
(e.g., article 200).
[0080] In step 310, a surface of substrate 110 is coated with a
slurry including colloidal metal-oxide precursor particles and
aluminum oxide particles. The surface of substrate 110 coated with
the slurry may be all or a portion of first surface 112, all or a
portion of second surface 114, and/or all or a portion of interior
surfaces 126 of vias 124. In some embodiments, only interior
surfaces 126 of vias 124 may be coated with slurry. In such
embodiments, any slurry coated on first surface 112 and/or second
surface 114 during coating of interior surfaces 126 is removed.
Suitable coating methods include, but are not limited to,
wash-coating, spin-coating, and dip-coating. The coating time may
be in the range of 10 seconds to 10 minutes.
[0081] In some embodiments the slurry may include an aqueous
solvent, such as DI (deionized) water. In some embodiments, slurry
may include a non-aqueous. In some embodiments, slurry may include
an aqueous solvent and a non-aqueous solvent.
[0082] Colloidal metal-oxide precursor particles, aluminum oxide
particles, and solvent are present at desired weight percentages
(wt %) in the slurry. In some embodiments, the slurry may include
solvent at a weight percent in the range of 75 wt % to 99 wt %,
including subranges. For example, the slurry may include 75 wt %,
76 wt %, 77 wt %, 78 wt %, 79 wt %, 80 wt %, 81 wt %, 82 wt %, 83
wt %, 84 wt %, 85 wt %, 86 wt %, 87 wt %, 88 wt %, 89 wt %, 90 wt
%, 91 wt %, 92 wt %, 93 wt %, 94 wt %, 95 wt %, 96 wt %, 97 wt %,
98 wt %, or 99 wt % solvent, or solvent at a weight percent within
any range having any two of these values as endpoints.
[0083] In some embodiments, the slurry may include colloidal
metal-oxide precursor particles at a weight percent in the range of
0.5 wt % to 10 wt %, including subranges. For example, the slurry
may include 0.5 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt
%, 7 wt %, 8 wt %, 9 wt %, or 10 wt % colloidal metal-oxide
precursor particles, or colloidal metal-oxide precursor particles
at a weight percent within any range having any two of these values
as endpoints. In some embodiments, the slurry may include aluminum
oxide particles at a weight percent in the range of 0.5 wt % to 10
wt %, including subranges. For example, the slurry may include 0.5
wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt
%, 9 wt %, or 10 wt % aluminum oxide particles, or aluminum oxide
particles at a weight percent within any range having any two of
these values as endpoints.
[0084] In some embodiments, the wt % of aluminum oxide particles in
the slurry may be greater than the wt % of colloidal metal-oxide
precursor particles in the slurry. In some embodiments, the wt % of
aluminum oxide particles in the slurry may be less than the wt % of
colloidal metal-oxide precursor particles in the slurry. In some
embodiments, the wt % of aluminum oxide particles in the slurry may
be equal to the wt % of colloidal metal-oxide precursor particles
in the slurry.
[0085] In some embodiments, the weight ratio of aluminum oxide
particles to colloidal metal-oxide precursor particles in the
slurry may be in the range of 1:1 to 20:1, including subranges. For
example, the weight ratio of aluminum oxide particles to colloidal
metal-oxide precursor particles in the slurry may be 1:1, 2:1, 3:1,
4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1,
16:1, 17:1, 18:1, 19:1, or 20:1, or within any range having any two
these values as endpoints. In some embodiments, the weight ratio of
aluminum oxide particles to colloidal metal-oxide precursor
particles in the slurry may be in the range of 3:1 to 20:1. In some
embodiments, the weight ratio of aluminum oxide particles to
colloidal metal-oxide precursor particles in the slurry may be in
the range of 3:1 to 10:1.
[0086] In some embodiments, the aluminum oxide particles in the
slurry may be nanoparticles (gamma(.gamma.)-aluminum oxide
particles). In some embodiments, the aluminum oxide particles may
have an average particle size in the range of 10 nanometers to 100
nanometers, including subranges. For example, the aluminum oxide
particles may have an average particle size of 10 nanometers, 20
nanometers, 25 nanometers, 30 nanometers, 40 nanometers, 50
nanometers, 60 nanometers, 70 nanometers, 75 nanometers, 80
nanometers, 90 nanometers, or 100 nanometers, or within any range
having any two of these values as endpoints.
[0087] The colloidal metal-oxide precursor particles in the slurry
may include, but are not limited to, aluminum oxide precursor
particles, silicon oxide precursor particles, titanium oxide
precursor particles, cerium oxide precursor particles, zirconium
oxide precursor particles, or a combination of two or more of these
types of metal-oxide precursor particles. In some embodiments, the
metal-oxide precursor particles may be nanoparticles. In some
embodiments, the colloidal metal-oxide precursor particles may have
an average particle size in the range of 50 nanometers to 100
nanometers, including subranges. For example, the aluminum oxide
particles may have an average particle size of 50 nanometers, 55
nanometers, 60 nanometers, 65 nanometers, 70 nanometers, 75
nanometers, 80 nanometers, 85 nanometers, 90 nanometers, 95
nanometers, or 100 nanometers, or within any range having any two
of these values as endpoints. In some embodiments, the colloidal
metal-oxide precursor particles may have an average particle size
in the range of 60 nanometers to 90 nanometers.
[0088] In some embodiments, the average particles size of aluminum
oxide particles in the slurry and the average size of the colloidal
metal-oxide precursor particles in the slurry may be different. In
some embodiments, the average particle size of the colloidal
metal-oxide precursor particles may be less than the average
particle size of the aluminum oxide particles. In some embodiments,
the average particle size of the colloidal metal-oxide precursor
particles may be greater than the average particle size of the
aluminum oxide particles. In some embodiments, the average particle
size of the colloidal metal-oxide precursor particles may be equal
to the average particle size of the aluminum oxide particles.
[0089] In some embodiments, the colloidal aluminum oxide precursor
particles may include colloidal aluminum oxide hydroxide (also
called boehmite or alumina hydrate) particles. In some embodiments,
the colloidal aluminum oxide hydroxide particles may be NYACOL.RTM.
Colloidal Alumina manufactured by Nyacol Nano Technologies, Inc. In
some embodiments, the colloidal aluminum oxide hydroxide particles
may be NYACOL.RTM. AL20 Colloidal Alumina manufactured by Nyacol
Nano Technologies, Inc. In some embodiments, the colloidal aluminum
oxide hydroxide particles may be DISPERAL.RTM. colloidal boehmite
alumina manufactured by Sasol. In some embodiments, the colloidal
aluminum oxide hydroxide particles may be DISPERAL.RTM. P2
colloidal boehmite alumina manufactured by Sasol.
[0090] In some embodiments, the colloidal titanium oxide precursor
particles may include colloidal titanium oxide particles with
hydroxyl groups on the surface (i.e., colloidal titanium oxide
hydroxide). In some embodiments, the colloidal titanium oxide
precursor particles may be NYACOL.RTM. Colloidal Titanium Dioxide
manufactured by Nyacol Nano Technologies, Inc. In some embodiments,
the colloidal titanium oxide precursor particles may be NYACOL.RTM.
TiSol A Colloidal Titanium Dioxide manufactured by Nyacol Nano
Technologies, Inc.
[0091] In some embodiments, the colloidal cerium oxide precursor
particles may include colloidal cerium acetate or cerium nitrite.
In some embodiments, the colloidal cerium oxide particles may be
NYACOL.RTM. Colloidal Cerium Oxide manufactured by Nyacol Nano
Technologies, Inc. In some embodiments, the colloidal cerium oxide
precursor particles may be NYACOL.RTM. CeO2(AC) manufactured by
Nyacol Nano Technologies, Inc.
[0092] In some embodiments, the colloidal silicon oxide precursor
particles may include colloidal silica particles with hydroxyl
groups on the surface (i.e., colloidal silicon oxide hydroxide).
For example, the colloidal silicon oxide precursor particles may
include LUDOX.RTM. colloidal silica.
[0093] In some embodiments, the colloidal zirconium oxide precursor
particles may include colloidal zirconia particles with hydroxyl
groups on the surface (i.e., colloidal zirconium oxide hydroxide)
or colloidal zirconium acetate. In some embodiments, the colloidal
zirconium oxide particles may be NYACOL.RTM. Colloidal Zirconia
manufactured by Nyacol Nano Technologies, Inc.
[0094] In some embodiments, the slurry may include a pore former to
control the formation of pores in a nanoporous metal-oxide layer
during calcination. In some embodiments, the pore former may
include polyethylene glycol (PEG). In some embodiments, the slurry
may include 8 wt % to 32 wt % pore former by weight of solids in
the slurry, including subranges. For example, the slurry may
include 8 wt %, 10 wt %, 16 wt %, 20 wt %, 24 wt %, 30 wt %, or 32
wt % pore former by weight of solids in the slurry, or pore former
at a weight percent within any range having any two of these values
as endpoints.
[0095] In step 320, the coating of slurry is calcinated on a
surface of substrate 110 to form a nanoporous metal-oxide layer on
the surface of substrate 110. Calcination is performed by applying
heat to the coating of slurry. During calcination, the coating of
slurry may be heated to a calcination temperature in the range of
300 degrees C. to 650 degrees C., including subranges. For example,
the coating of slurry may be heated to a temperature of 300 degrees
C., 350 degrees C., 400 degrees C., 450 degrees C., 500 degrees C.,
550 degrees C., 600 degrees C., or 650 degrees C. during
calcination, or within any range having any two of these values as
endpoints. In some embodiments, the coating of slurry may be heated
to a temperature in the range of 400 degrees C. to 500 degrees C. A
calcination temperature may be measured by a thermal couple
disposed in the oven.
[0096] Calcination of the coating of slurry at the calcination
temperature may be performed for a time in the range of 5 minutes
to 6 hours, including subranges. For example, calcination may be
performed for 5 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4
hours, 5 hours, 6 hours, or within any range having any two of
these values as end points. In some embodiments, calcination may be
performed for a time in the range of 30 minutes to 5 hours. In some
embodiments, the temperature ramp rate for a calcination process
may be in the range of 20 degrees C./hour to 300 degrees C./hour,
including subranges. For example, the temperature ramp rate may be
20 degrees C./hour, 50 degrees C./hour, 100 degrees C./hour, 150
degrees C./hour, 200 degrees C./hour, 250 degrees C./hour, 300
degrees C./hour, or a ramp rate within in range having any two of
these values as endpoints. In some embodiments, calcination may be
performed in an oven. In some embodiments, calcination may be
performed on a hot plate. For example, calcination may be performed
directly on a hot plate with a set temperature of 300 degrees C.
for 5 minutes
[0097] In some embodiments, the coating of slurry on substrate 110
may be dried prior to calcinating the slurry. In some embodiments,
drying may be performed at a temperature in the range of room
temperature (23 degrees C.) to 110 degrees C. In some embodiments,
drying may be performed a time in the range of 5 minutes to 1 hour.
In some embodiments, drying may include flowing nitrogen gas over
the coating of slurry.
[0098] In step 330, the nanoporous metal-oxide layer may be charged
to ensure a suitable cationic charge state of the glass surface for
catalyst adsorption in step 340. The palladium complexes adsorbed
in step 340 typically exist in anionic form and, therefore, their
adsorption on the nanoporous metal-oxide layer can be enhanced by
cationic surface groups such as protonated amines. A suitable
number of palladium complexes can provide a sufficient number of
nucleation sites within the nanoporous layer to seed deposition of
a metal material during electroless plating. By providing a
suitable amount of nucleation sites, a suitable bond strength
between a plated metallic film and a nanoporous metal-oxide layer
can be achieved, which facilitates the adhesion between the
metallic film and surfaces of substrate 110.
[0099] Charging the nanoporous metal-oxide layer may include
treating the nanoporous metal-oxide layer with an aminosilane, such
as aminopropyltriethoxysilane (APTES). In some embodiments,
treating the nanoporous metal-oxide layer with APTES may include
soaking the nanoporous metal-oxide layer in 1.0 vol % APTES
solution (95 mL methanol, 4 mL H.sub.2O, and 1 mL APTES) at room
temperature for 15 minutes. In some embodiments, charging the
nanoporous metal-oxide layer may include treating the nanoporous
metal-oxide layer with cationic polymers. In some embodiments, the
treated the nanoporous metal-oxide layer may be dried after step
330. For example, the treated the nanoporous metal-oxide layer may
be dried in an oven at approximately 120 degrees C. for 30
minutes.
[0100] In step 340, palladium complexes may be adsorbed on the
nanoporous metal-oxide layer. This palladium complex adsorption
step may include treatment of the nanoporous metal-oxide layer with
K.sub.2PdCl.sub.4 (potassium tetrachloropalladate), ionic
palladium, and/or a Sn/Pd (tin/palladium) colloidal solution. If
K.sub.2PdCl.sub.4 or ionic palladium are used in step 340, step 340
may include reduction of the K.sub.2PdCl.sub.4 or ionic palladium
into metallic palladium. In such embodiments, the reduction of
K.sub.2PdCl.sub.4 or ionic palladium forms palladium particles.
Such a reduction may be performed by reacting the K.sub.2PdCl.sub.4
or ionic palladium with dimethylaminoborane (DMAB). If a Sn/Pd
colloidal solution is used in step 340, the palladium is already in
Pd.sup.0 form with a tin shell around it. The tin shell can be
removed by acid etching.
[0101] This treatment in step 340 results in the adsorption of
metallic palladium particles (Pd.sup.0 particles) on surfaces of
the nanoporous metal-oxide layer, including interior surfaces
defining the porous structure of nanoporous metal-oxide layer. The
adsorbed palladium particles may have an average particle size
smaller than the average pore size of the nanoporous metal-oxide
layer. In some embodiments, the adsorbed palladium particles may
have an average particle size in the range of 1 nanometer to 10
nanometers, including subranges. For example, the adsorbed
palladium particles may have an average particle size of 1
nanometer, 2 nanometers, 3 nanometers, 4 nanometers, 5 nanometers,
6 nanometers, 7 nanometers, 8 nanometers, 9 nanometers, 10
nanometers, or within any range having any two of these values as
endpoints.
[0102] The surface roughness and/or high porosity of the nanoporous
metal-oxide layer on substrate 110 leads to more palladium catalyst
inside the nanoporous metal-oxide layer after step 340,
particularly if the cationic surface treatment of step 330 is used.
More palladium catalyst leads to more metallic material inside the
nanoporous metal-oxide layer, thus creating strong mechanical
interlocking between the nanoporous metal-oxide layer and a plated
metallic film. In some embodiments, a different catalyst material
may be used in step 340 to catalyze the nanoporous metal-oxide
layer prior to metallic plating.
[0103] In steps 350 and 360, the nanoporous metal-oxide layer is
plated with a metal to form a metallic film, which is adhered to
surfaces of substrate 110 via the nanoporous metal-oxide layer.
Step 350 includes an electroless plating method for plating metal
on the nanoporous metal-oxide layer. The electroless plating method
may fill pores of the nanoporous metal-oxide layer with a metallic
material and coat an exterior surface of the nanoporous metal-oxide
layer (e.g., exterior surface 412 shown in FIG. 4C) with a metallic
film. Filling the pores of the nanoporous metal-oxide layer with
the metallic material mechanically interlocks the metallic film to
surfaces of substrate 110. In some embodiments, the metal plated in
step 350 may include copper. Other metallic materials that may be
plated in step 350 include, but are not limited to, silver, gold,
ruthenium, rhodium, palladium, osmium, iridium and platinum.
[0104] The thickness of the metallic film plated in step 350 may be
about 100 nanometers to about 200 nanometers. In some embodiments,
the thickness of the metallic film formed in step 350 may be in the
range of 50 nanometers to 250 nanometers, including subranges. For
example, the thickness of the metallic film formed in step 350 may
be 50 nanometers, 75 nanometers, 100 nanometers, 125 nanometers,
150 nanometers, 175 nanometers, 200 nanometers, 225 nanometers, or
250 nanometers, or within any range having any two of these values
as endpoints.
[0105] Step 360 includes an electroplating method for plating metal
on an exterior surface of the metallic film deposited in step 350
(e.g., exterior surface 424 of film 422 shown in FIG. 4C). The
electroplating method may form a film (e.g., film 426) on the top
surface of the electrolessly plated film. In some embodiments, the
metal plated in step 360 may include copper. Other metallic
materials that may be plated in step 360 include, but are not
limited to, silver, gold, ruthenium, rhodium, palladium, osmium,
iridium and platinum.
[0106] Step 360 may be performed if a metallic film thicker than
that formed in step 350 is desired. Electroless plating has certain
advantages, such as the ability to plate onto an initially
non-conductive surface. But, electroless plating can be slow when
thick layers are desired. Once an initial film of electroless metal
is deposited to form a conductive surface, electroplating may be
used to more quickly plate a thicker film of metal. In some
embodiments, electroless plating alone may be used to plate the
metallic film. In such embodiments, step 360 may not be included,
and step 350 may be used to deposit a metallic film with a desired
thickness.
[0107] The thickness of the metallic film plated in step 360 may be
greater than 1 micron (micrometer, .mu.m). In some embodiments, the
thickness of the metallic film formed in step 360 may be in the
range of 1 micron to 100 microns, including subranges. For example,
the thickness of the metallic film formed in step 360 may be 1
micron, 5 microns, 10 microns, 20 microns, 30 microns, 40 microns,
50 microns, 60 microns, 70 microns, 80 microns, 100 microns, or
within a range having any two of these values as endpoints. In
embodiments not including step 360, the metallic film plated in
step 350 may have any of these thicknesses.
[0108] In some embodiments, the metallic film formed in step 350
and/or step 360 may completely fill vias 124 of substrate 110 For
example, FIG. 6 shows metal plating 620 completely filing vias 124
of article 600. In other words, the metallic film may completely
fill the volume defined by the interior surfaces 126 of vias 124.
In some embodiments, the metallic film formed in step 350 and/or
step 360 may not completely fill vias 124 of substrate 110. In
other words, a portion of the volume defined by the interior
surfaces 126 of vias 124 may remain open after plating of the
metallic film. By controlling the thickness of the metallic film
formed in 350 and/or step 360, the degree at which the vias are
filled can be controlled.
[0109] FIGS. 4A-4C illustrate how substrate 110 is processed during
various steps of method 300. Specifically, FIGS. 4A-4C show region
400 of FIG. 1 and how an interior surface 126 of a via 124 is
processed during various steps of method. Other surfaces, such as
first surface 112 and second surface 114 may be processed in the
same way. Further, while FIGS. 4A-4C show a single via 124, all
vias 124 of substrate may be processed as shown in FIGS. 4A-4C.
Although FIGS. 4A-4C show a specific substrate geometry, any
substrate geometry for which metallization is desired may be
used.
[0110] FIG. 4A shows interior surface 126 of a via 124 prior to
coating interior surface 126 with a slurry. FIG. 4B shows a
nanoporous metal-oxide layer 410 coated on interior surface 126 of
via 124. As discussed in regards to steps 310 and 320, nanoporous
metal-oxide layer 410 is formed by coating a slurry on interior
surface 126 and calcinating the slurry to create a nanoporous
metal-oxide layer 410 having a desired porous structure (pore size,
distribution, and geometry).
[0111] In some embodiments, nanoporous metal-oxide layer 410 may
have an average pore size in the range of 5 nanometers to 30
nanometers, including subranges. For example, nanoporous
metal-oxide layer 410 may have an average pore size of 5
nanometers, 7.5 nanometers, 10 nanometers, 12.5 nanometers, 15
nanometers, 17.5 nanometers, 20 nanometers, 22.5 nanometers, 25
nanometers, 27.5 nanometers, or 30 nanometers, or within any range
having any two of these values as endpoints. In some embodiments,
nanoporous metal-oxide layer 410 may have an average pore size in
the range of 5 nanometers to 10 nanometers, including subranges.
For example, nanoporous metal-oxide layer 410 may have an average
pore size of 5 nanometers, 5.5 nanometers, 6 nanometers, 6.5
nanometers, 7 nanometers, 8.5 nanometers, 9 nanometers, 9.5
nanometers, or 10 nanometers, or within any range having any two of
these values as endpoints. In some embodiments, nanoporous
metal-oxide layer 410 may have an average pore size in the range of
6 nanometers to 8 nanometers, including subranges. For example,
nanoporous metal-oxide layer 410 may have an average pore size of 6
nanometers, 6.25 nanometers, 6.5 nanometers, 6.75 nanometers, 7
nanometers, 7.25 nanometers, 7.5 nanometers, 7.75 nanometers, or 8
nanometers, or within any range having any two of these values as
endpoints.
[0112] In some embodiments, nanoporous metal-oxide layer 410 may
have a pore volume in the range of 0.3 cubic centimeters per gram
(cc/g) to 10 cubic centimeters per gram (cc/g), including
subranges. For example, nanoporous metal-oxide layer 410 may have a
pore volume of 0.3 cc/g, 0.5 cc/g, 1 cc/g, 2 cc/g, 3 cc/g, 4 cc/g,
5 cc/g, 6 cc/g, 7 cc/g, 8 cc/g, 9 cc/g, or 10 cc/g, or within any
range having any two these values as endpoints. In some
embodiments, nanoporous metal-oxide layer 410 may have a pore
volume in the range of 0.3 cc/g to 0.6 cc/g, including subranges.
For example, nanoporous metal-oxide layer 410 may have a pore
volume of 0.3 cc/g, 0.35 cc/g, 0.4 cc/g, 0.45 cc/g, 0.5 cc/g, 0.55
cc/g, or 0.6 cc/g, or within any range having any two these values
as endpoints.
[0113] In some embodiments, nanoporous metal-oxide layer 410 may
have a thickness in the range of 10 nanometers to 200 nanometers,
including subranges. For example, the thickness of nanoporous
metal-oxide layer 410 may be 10 nanometers, 20 nanometers, 30
nanometers, 40 nanometers, 50 nanometers, 60 nanometers, 70
nanometers, 80 nanometers, 90 nanometers, 100 nanometers, 110
nanometers, 120 nanometers, 130 nanometers, 140 nanometers, 150
nanometers, 160 nanometers, 170 nanometers, 180 nanometers, 190
nanometers, 200 nanometers, or within a range having any two of
these values as endpoints. In some embodiments, the thickness of
nanoporous metal-oxide layer 410 may be in the range of 50
nanometers to 150 nanometers.
[0114] FIG. 4C shows exterior surface 412 of nanoporous metal-oxide
layer 410 plated with metallic film 420 after step 350 and/or step
360. Metallic film 420 includes electrolessly plated metallic film
422 plated on an exterior surface 412 of nanoporous metal-oxide
layer 410 and electroplated metallic film 426 plated on an exterior
surface 424 of electrolessly plated metallic film 422. In
embodiments where only electroless plating is used, metallic film
420 will only include electrolessly plated metallic film 422 plated
at a desired thickness.
[0115] FIGS. 5A and 5B illustrate the processing of nanoporous
metal-oxide layer 410 during catalyzation with palladium particles
in step 340 and electroless plating in step 350. FIG. 5A shows
Pd.sup.0 particles 500 penetrated into nanopores 510 of nanoporous
metal-oxide layer 410 and adsorbed onto surfaces 512 of the
nanopores 510. FIG. 5B shows nanopores 510 filed with electrolessly
plated metal 520 (e.g., copper) after step 350.
[0116] FIG. 6 shows an article 600 according to some embodiments.
Article 600 includes substrate 110 with a plurality of vias 124
formed in first surface 112, each via 124 having an interior
surface 126. A nanoporous metal-oxide layer 610 is coated on the
interior surface 126 of each of the plurality of vias 124.
Nanoporous metal-oxide layer 610 may be the same as or similar to
nanoporous metal-oxide layer 410. Disposed on nanoporous
metal-oxide layer 610 in each of the plurality of vias 124 is a
metal plating 620. Metal plating may be a plated metallic film the
same as or similar to metallic film 420. In some embodiments, the
metal plating 620 may include copper. In some embodiments, article
600 may be an electrical interposer, such as a 3D
(three-dimensional) interposer.
[0117] In some embodiments, as shown in FIG. 6, nanoporous
metal-oxide layer 610 may be coated on at least a portion of first
surface 112 of substrate 110. In some embodiments, nanoporous
metal-oxide layer 610 may be coated on at least a portion of second
surface 114 of substrate 110. In some embodiments, metal plating
620 may be disposed on all portions of article 600 coated with
nanoporous metal-oxide layer 610. In some embodiments, metal
plating 620 may be disposed on at least a portion of nanoporous
metal-oxide layer 610 coated on first surface 112. In some
embodiments, metal plating 620 may be disposed on at least a
portion of nanoporous metal-oxide layer 610 coated on second
surface 114. In some embodiments, metal plating 620 disposed on
nanoporous metal-oxide layer 610 coated on first surface 112 and/or
second surface 114 of substrate 110 may be capable of passing a
3N/cm tape test after being annealed at 350 degrees C. for 30
minutes.
[0118] The following examples illustrate the effectiveness of
nanoporous metal-oxide layers according to embodiments of the
present application. In particular, the following examples
illustrate the effectiveness of nanoporous metal-oxide layers made
from a slurry including colloidal metal-oxide precursor particles
and aluminum oxide particles according to embodiments discussed
herein.
Example 1: Spin-Coated AL20 Coating
[0119] In this example, two 6 inch diameter by 0.7 millimeter (mm)
thick Eagle XG.RTM. (EXG) glass wafers were spin-coated with
as-received 1:1 diluent to AL20 solution purchased from Nano
Technologies, Inc. after soaking for 1 minute. In other words, the
wafers were spin coated with a slurry including only colloidal
metal-oxide precursor particles (aluminum oxide hydroxide
particles). The first wafer was spun at 500 rotations per minute
(rpm) for 30 seconds and at 1000 rpm for 15 seconds and then at 300
rpm for 15 seconds. The second wafer was spun at 1000 rpm for 30
seconds, and again at 1000 rpm for 15 seconds, and then at 300 rpm
for 15 seconds. The coated wafers were baked on hot plate at 300
degrees C. for 3 minutes. The spin-coated EXG wafers had a uniform
nanoporous alumina layer with a thickness of 318 nm, as shown in
SEM images 700 of FIG. 7. It was found that lower rpm spinning and
ramp improved the uniformity of the AL20 coating.
[0120] After APTES treatment for 15 minutes, the coated wafers were
baked in an oven for 30 minutes. Then, the wafers were soaked in a
K.sub.2PdCl.sub.4 solution for 2 minutes and dried. APTES treatment
included soaking the coated wafers in a 1.0 vol % APTES solution
(95 mL methanol, 4 mL H.sub.2O and 1 mL APTES) at room temperature
for 15 minutes.
[0121] After drying, the samples were electrolessly plated with a
copper film. The electroless copper thickness was 47 nanometers.
After electroless plating, a copper film was electroplated on the
electrolessly plated copper film. The electroplating was performed
using an electric resistance of 1.5 ohms per centimeter squared
(ohm/cm.sup.2). The electroplated copper film thickness was 2.5
microns.
[0122] After electroplating, the adhesion force was measured by a
peel test to be greater than 3.7 N/cm. However, all the samples
failed a 3N/cm tape test after electroplating of 2.5 microns of
copper film.
Example 2: Wash-Coated AL20 Coating
[0123] In this example, two 6 inch diameter by 0.7 mm thick EXG
glass wafers were wash-coated with a slurry of as-received 1:1
diluent to AL20 solution purchased from Nano Technologies, Inc.
Both samples were then baked to calcinate the slurry on the wafers.
After baking, the first sample was APTES treated, catalyzed with
palladium particles, and electrolessly plated with a copper film.
APTES treatment included soaking the first sample in a 1.0 vol %
APTES solution (95 mL methanol, 4 mL H.sub.2O and 1 mL APTES) at
room temperature for 15 minutes. The second wafer was processed in
the same way as the first, the exception that APTES treatment was
not performed on the second sample. The wash-coated wafers had a
nanoporous metal-oxide layer with a thickness of 48 nanometers, as
shown in SEM images 800 and 850 of FIGS. 8A and 8B.
[0124] The first wafer showed a full coverage copper film but with
some surface texture. The second wafer had a discontinuous copper
film. This example shows that APTES treatment can improve
electroless plating of a metallic film on a nanoporous metal-oxide
layer.
Example 3: Dip-Coated Alumina Nanoparticle-AL20 Coating
[0125] In this example, 12 pieces of 2 inch by 2 inch by 0.7 mm
thick EXG glass substrates were dip-coated with two different
aqueous slurries containing a mixture of gamma(.gamma.)-alumina
particles (aluminum oxide nanoparticles) and as-received AL20. In
other words, the substrates were dip-coated with a slurry including
both metal oxide particles and colloidal metal-oxide precursor
particles. The first slurry included 5 wt % gamma-alumina particles
and 5 wt % AL20 and the second slurry included 1 wt % gamma-alumina
particles and 1 wt % AL20. Two different withdraw speeds, 50
mm/minute and 250 mm/minute, were chosen for each slurry.
[0126] The gamma-alumina particles had a Brunauer-Emmett-Teller
(BET) surface area of 173.8 meters squared per gram (m.sup.2/g),
which led to an average calculated particle size of 10 nanometers.
SEM analysis indicated that the gamma-alumina particles had
particle size of around 50 nanometers. Dynamic light scattering
data indicated that the two slurries had similarly wide particle
size distribution in the range of 30 nanometers to 2 microns, as
shown in graph 900 of FIG. 9.
[0127] After drying in 120 degrees C. for 1 hour, the samples were
calcinated in an oven at 400 degrees C. for 1 hour with a heating
and cooling rate of 60 degrees C./hour. The thickness of nanoporous
metal-oxide layers formed on the substrates were measured by SEM to
be in the range of about 15 nanometers to about 83 nanometers. The
SEM images 1000 and 1050 of FIGS. 10A and 10B show an exemplary
83.8 nanometer thick nanoporous metal-oxide layer.
[0128] After calcination, half of the nanoporous metal-oxide layers
were treated with APTES and the other half were not. APTES
treatment included soaking the substrates in a 1.0 vol % APTES
solution (95 mL methanol, 4 mL H.sub.2O and 1 mL APTES) at room
temperature for 15 minutes. Then, all the nanoporous metal-oxide
layers were catalyzed using a K.sub.2PdCl.sub.4 solution that was
reduced with DMAB. And after catalyzation, the nanoporous
metal-oxide layers were electrolessly plated with a metallic
film.
[0129] The test results for four of the substrates, two coated with
the 5 wt %/5 wt % slurry and two coated with the 1 wt %/1 wt %
slurry, are shown below in Table 1. As shown in Table 1, a higher
concentration slurry and a faster withdraw speed resulted in a
thicker nanoporous metal-oxide layer. Also, a higher concentration
slurry and a faster withdraw speed resulted in a higher surface
roughness for a nanoporous metal-oxide layer. The thicker
nanoporous layers of samples #4-9 and #4-10 appeared more uniform
than the thinner nanoporous layers of samples #4-11 and #4-12.
TABLE-US-00001 TABLE 1 Comparison of different substrates
dip-coated with alumina nanoparticle-AL20 slurries Withdrawal
Surface speed, Nanoporous layer roughness Sample Slurry mm/minute
thickness, nm Ra, nm #4-9 5% .gamma.-alumina + 50 63 11.9 5% AL20
#4-10 5% .gamma.-alumina + 250 83 39.1 5% AL20 #4-11 1%
.gamma.-alumina + 50 15 1.7 1% AL20 #4-12 1% .gamma.-alumina + 250
30 3.7 1% AL20
[0130] Furthermore, as with Example 2, it was found that APTES
treatment significantly improves the coverage of a copper film on a
nanoporous metal-oxide layer. With APTES treatment full coverage of
a copper film was achieved. This example illustrates the ability to
form suitable nanoporous metal-oxide layers by calcinating a
coating of slurry including both metal oxide particles and
colloidal metal-oxide precursor particles.
Example 4: Dip-coated AL20 Coating with Copper Plating
[0131] In this example, 2 inch by 2 inch by 0.7 mm thick EXG glass
substrates were dip-coated with four diluted AL20 slurries with
1:1, 1:3, 1:6, and 1:12 AL20 to water dilution ratios. In other
words, the wafers were coated with slurries including only
colloidal metal-oxide precursor particles (aluminum oxide hydroxide
particles) at different dilution ratios. First, each substrate was
dip-coated using the same process and the same withdrawal speed of
50 mm/minute. Then, after drying in an oven at 120 degrees C. for 1
hour, the substrates were coated again with the same dip-coating
process followed by drying in an oven at 120 degrees C.
[0132] After drying, the coated substrates were calcined in an oven
at 400 degrees C. for 1 hour with a heating and cooling rate of 60
degrees C./hour. Table 2 below lists the nanoporous metal-oxide
layer thickness of the calcined AL20 coating samples measured by
SEM.
TABLE-US-00002 TABLE 2 Comparison of different substrates
dip-coated with AL20 slurries Ratio of AL20 to DI AL20 coating
Sheet resistance, Sample water by weight thickness, nm ohm/cm.sup.2
#10-2 1:1 415 1.11 #23-1 1:3 149 1.13 #23-2 1:6 73 1.16 #23-3 1:12
50 1.25
[0133] The calcined nanoporous metal-oxide layers then went through
a cleaning process, and then were soaked in a 1.0 vol % APTES
solution (95 mL methanol, 4 mL H.sub.2O and 1 mL APTES) at room
temperature for 15 min. After a gentle rinse with DI water three
times, the substrates were placed in an oven at 120 degrees C. for
30 minutes to dry. After drying, the treated nanoporous metal-oxide
layers were soaked in a K.sub.2PdCl.sub.4 solution at 45 degrees C.
for 3 minutes, followed by reduction into metallic palladium
particles at room temperature by DMAB.
[0134] Electroless copper plating was conducted in an electroless
plating bath at 34 degrees C. for 2 minutes. FIG. 11 shows an
exemplary photograph 1100 of one of the plated samples showing that
a full coverage copper film was formed on each nanoporous
metal-oxide layer. After drying the substrates with a nitrogen
spray gun, the substrates were annealed in a vacuum oven at 250
degrees C. for 30 minutes. Immediately after drying, the sheet
resistance of the copper films was measured with a single point
measurement. The measured sheet resistance, measured in ohm per
square centimeter (ohm/cm.sup.2), of each sample is listed in Table
2.
[0135] The electroless-plated samples were then placed in a 1M
(molar) CuSO.sub.4 (copper sulfate) solution for electroplating
with a 50 mA (milliampere) current for 1 hour. After manually
drying the samples with a nitrogen spray gun, a 3N/cm tape test was
conducted on each sample. All the samples passed the test.
Photograph 1200 of FIG. 12 shows three of the tested samples
(#23-1, #23-2, and #23-3) after the 3N/cm tape test. But, when the
3N/cm tape test was repeated after annealing the samples in vacuum
oven at 350 degrees C. for 30 minutes with a ramp rate of 3 C/min,
all samples failed the test. Photograph 1300 in FIG. 13 shows the
electroplated copper removed from samples #23-1, #23-2, and #23-3
by the tape.
[0136] Upon examination of the surface morphology of the samples,
it was discovered that failure of the sample in the second 3N/cm
tape test was due to weak bonding between the electroplated copper
film and the nanoporous alumina layer formed by calcinating the
coating of slurries including only colloidal metal-oxide precursor
particles. FIG. 14A shows an SEM image 1400 of the surface
morphology of sample #23-1 with 60 degree tilt. In image 1400 it
can be seen that the electroplated copper film has been removed
from the nanoporous alumina layer by the tape. SEM image 1450 in
FIG. 14B is a zoomed-in image of the interface between the
nanoporous alumina layer and nanoporous alumina layer in image 1400
showing the removal of the electroplated copper film.
Example 5: Dip-Coated Alumina Nanoparticle and AL20 Coating with
Copper Plating
[0137] In this example, three 2 inch by 2 inch by 0.7 mm thick EXG
glass substrates were dip-coated with a slurry having 5% wt %
gamma(.gamma.)-alumina particles (aluminum oxide nanoparticles) and
5 wt % as-received AL20 at a withdrawal speed of 50 mm/min. The
diluent for the slurry was DI water. After drying in an oven at 120
degrees C. for 1 hour, the samples were coated again with the same
slurry followed by drying at 120 degrees C. The dried samples were
then calcined at three different temperature profiles, 400 degrees
C. for 1 hour, 400 degrees C. for 6 hours, and 550 degrees C. for 1
hour, respectively, to form nanoporous metal-oxide layers on the
glass substrates.
[0138] After calcination, the samples were cleaned and then soaked
in a 1.0 vol % APTES solution (95 mL methanol, 4 mL H.sub.2O and 1
mL APTES) at room temperature for 15 minutes. After a gentle rinse
with DI water three times, the samples were placed in an oven at
120 degrees C. for 30 minutes. Then, the samples were soaked in a
K.sub.2PdCl.sub.4 solution at 45 degrees C. for 3 minutes, followed
by reduction into metallic palladium particles at room temperature
by DMAB.
[0139] After catalyzation, the samples were placed in an
electroless plating bath at 34 degrees C. for 2 minutes to
electrolessly plate a copper film on the nanoporous metal-oxide
layers. After manually drying the samples with a nitrogen spray
gun, the samples were annealed in a vacuum oven at 250 degrees C.
for 30 minutes. The sheet resistance was immediately measured with
single point measurement. Each of the samples showed a sheet
resistance in the range of 0.9 to 1.1 ohm per square centimeter
(ohm/cm.sup.2). Photograph 1500 in FIG. 15 shows all three samples
after electroless plating.
[0140] The electrolessly-plated samples were then placed in a 1M
(molar) CuSO.sub.4 solution for electroplating with a 50 mA current
for 1 hour to electroplate copper on the electrolessly-plated
copper film. Photograph 1600 in FIG. 16 shows all three samples
after electroplating. And FIG. 17 shows an SEM image 1700 of the
surface morphology of an electroplated copper film deposited on an
electrolessly-plated film for one of the samples. Image 1700 shows
electroplated copper crystals having a size in the range of 3
microns to 5 microns. These electroplated copper crystals are
significantly larger than the electrolessly-plated copper crystals
underneath the electroplated copper crystals. Also, the
electroplated copper crystals are more densely deposited than the
electrolessly-plated copper crystals. As shown in SEM images 1800
and 1850 of FIGS. 18A and 18B, respectively, the
electrolessly-plated copper film was about 100 nanometers thick to
about 200 nanometers thick and the electroplated copper film was
about 6 microns thick.
[0141] After manually drying the samples with a nitrogen spray gun,
a 3 N/cm tape test was conducted on each sample. All samples passed
the 3 N/cm tape test. After this first 3 N/cm tape test, the
samples were annealed in a vacuum oven at 350 degrees C. for 30
minutes with a ramp rate of 3 degrees C./minute. Then, the 3 N/cm
tape test was repeated on all the samples. Unlike the samples of
Example 4, all samples passed the second N/cm tape test.
[0142] FIGS. 19A-19E show TEM/EDX (transmission electron microscopy
energy-dispersive X-ray spectroscopy) images 1900, 1910, 1920,
1930, and 1940 of a cross-section of the sample calcined at 400
degrees C. for 1 hour. Image 1900 shows locations of palladium,
copper, aluminum, and silicon in the cross-section. Image 1910
shows the location of palladium in the cross-section. Image 1920
shows the location of copper in the cross-section. Image 1930 shows
the location of aluminum in the cross-section. Image 1940 shows the
location of silicon in the cross-section.
[0143] The images in FIGS. 19A-19E show that the sample had a
sandwich structure with a nanoporous aluminum oxide layer 1904
disposed between a copper film 1906 and a EXG glass substrate 1902.
The presence of palladium and copper inside the nanoporous aluminum
oxide layer 1904 is shown in shown in images 1910 and 1920. The
porosity of nanoporous aluminum oxide layer 1904 on the glass
substrate 1902 in combination with cationic surface treatment led
to a high concentration of palladium catalyst on the nanoporous
aluminum oxide layer 1904 as well as mechanical interlocking
between the nanoporous aluminum oxide layer 1904 and the copper
film 1906.
[0144] By comparing Examples 4 and 5, it can be seen that
metal-oxide layers formed by calcinating a coating of slurry having
both colloidal metal-oxide precursor particles and aluminum oxide
particles results in improved mechanical interlocking and tape test
performance compared to metal-oxide layers formed by calcinating a
slurry having only colloidal metal-oxide precursor particles. After
annealing, the samples of Example 4 failed the 3N/cm tape test,
whereas the samples of Example 5 passed the 3N/cm tape test after
annealing.
[0145] To evaluate differences between the samples of Example 4 and
Example 5, the pore size and the pore volume of the nanoporous
aluminum oxide layers on the samples were measured. BJH nitrogen
adsorption and desorption analysis showed that the mean pore size
of the Alumina Nanoparticle-AL20 layers of Example 5 was 7.25
nanometers and the mean pore size of the AL20 layers of Example 4
was 4.29 nanometers. The pore volume of the Alumina
Nanoparticle-AL20 layers of Example 5 was 0.45 cc/g and the pore
volume of the AL20 layers of Example 4 was 0.37 cc/g. Without being
bound by theory, it is believed the larger pore size and higher
porosity of the Alumina Nanoparticle-AL20 layers of Example 5 led
to better mechanical interlock and thus higher adhesion between the
plated copper and the glass substrate compared to the AL20 layers
of Example 4, which failed after electroplating and annealing.
[0146] Examples of suitable glass or glass substrates described
herein include soda lime glass, alkali aluminosilicate glass,
alkali containing borosilicate glass and alkali aluminoborosilicate
glass. In some variants, the glass may be free of lithia. As used
herein the term "glass" is meant to include any material made at
least partially of glass, including glass and glass-ceramics.
"Glass-ceramics" include materials produced through controlled
crystallization of glass. In embodiments, glass-ceramics have about
30% to about 90% crystallinity. Non-limiting examples of glass
ceramic systems that may be used include
Li.sub.2O.times.Al.sub.2O.sub.3.times.nSiO.sub.2 (i.e. LAS system),
MgO.times.Al.sub.2O.sub.3.times.nSiO.sub.2 (i.e. MAS system), and
ZnO.times.Al.sub.2O.sub.3.times.nSiO.sub.2 (i.e. ZAS system).
[0147] While various embodiments have been described herein, they
have been presented by way of example, and not limitation. It
should be apparent that adaptations and modifications are intended
to be within the meaning and range of equivalents of the disclosed
embodiments, based on the teaching and guidance presented herein.
It therefore will be apparent to one skilled in the art that
various changes in form and detail can be made to the embodiments
disclosed herein without departing from the spirit and scope of the
present disclosure. The elements of the embodiments presented
herein are not necessarily mutually exclusive, but may be
interchanged to meet various situations as would be appreciated by
one of skill in the art.
[0148] Embodiments of the present disclosure are described in
detail herein with reference to embodiments thereof as illustrated
in the accompanying drawings, in which like reference numerals are
used to indicate identical or functionally similar elements.
References to "one embodiment," "an embodiment," "some
embodiments," "in certain embodiments," etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same embodiment.
Further, when a particular feature, structure, or characteristic is
described in connection with an embodiment, it is submitted that it
is within the knowledge of one skilled in the art to affect such
feature, structure, or characteristic in connection with other
embodiments whether or not explicitly described.
[0149] The examples are illustrative, but not limiting, of the
present disclosure. Other suitable modifications and adaptations of
the variety of conditions and parameters normally encountered in
the field, and which would be apparent to those skilled in the art,
are within the spirit and scope of the disclosure.
[0150] The term "or," as used herein, is inclusive; more
specifically, the phrase "A or B" means "A, B, or both A and B."
Exclusive "or" is designated herein by terms such as "either A or
B" and "one of A or B," for example.
[0151] The indefinite articles "a" and "an" to describe an element
or component means that one or at least one of these elements or
components is present. Although these articles are conventionally
employed to signify that the modified noun is a singular noun, as
used herein the articles "a" and "an" also include the plural,
unless otherwise stated in specific instances. Similarly, the
definite article "the," as used herein, also signifies that the
modified noun may be singular or plural, again unless otherwise
stated in specific instances.
[0152] As used in the claims, "comprising" is an open-ended
transitional phrase. A list of elements following the transitional
phrase "comprising" is a non-exclusive list, such that elements in
addition to those specifically recited in the list may also be
present. As used in the claims, "consisting essentially of" or
"composed essentially of" limits the composition of a material to
the specified materials and those that do not materially affect the
basic and novel characteristic(s) of the material. As used in the
claims, "consisting of" or "composed entirely of" limits the
composition of a material to the specified materials and excludes
any material not specified.
[0153] The term "wherein" is used as an open-ended transitional
phrase, to introduce a recitation of a series of characteristics of
the structure.
[0154] Where a range of numerical values is recited herein,
comprising upper and lower values, unless otherwise stated in
specific circumstances, the range is intended to include the
endpoints thereof, and all integers and fractions within the range.
It is not intended that the scope of the claims be limited to the
specific values recited when defining a range. Further, when an
amount, concentration, or other value or parameter is given as a
range, one or more preferred ranges or a list of upper preferable
values and lower preferable values, this is to be understood as
specifically disclosing all ranges formed from any pair of any
upper range limit or preferred value and any lower range limit or
preferred value, regardless of whether such pairs are separately
disclosed. Finally, when the term "about" is used in describing a
value or an end-point of a range, the disclosure should be
understood to include the specific value or end-point referred to.
Whether or not a numerical value or end-point of a range recites
"about," the numerical value or end-point of a range is intended to
include two embodiments: one modified by "about," and one not
modified by "about."
[0155] As used herein, the term "about" means that amounts, sizes,
formulations, parameters, and other quantities and characteristics
are not and need not be exact, but may be approximate and/or larger
or smaller, as desired, reflecting tolerances, conversion factors,
rounding off, measurement error and the like, and other factors
known to those of skill in the art.
[0156] The terms "substantial," "substantially," and variations
thereof as used herein are intended to note that a described
feature is equal or approximately equal to a value or description.
For example, a "substantially planar" surface is intended to denote
a surface that is planar or approximately planar. Moreover,
"substantially" is intended to denote that two values are equal or
approximately equal. In some embodiments, "substantially" may
denote values within about 10% of each other, such as within about
5% of each other, or within about 2% of each other.
[0157] The present embodiment(s) have been described above with the
aid of functional building blocks illustrating the implementation
of specified functions and relationships thereof. The boundaries of
these functional building blocks have been arbitrarily defined
herein for the convenience of the description. Alternate boundaries
can be defined so long as the specified functions and relationships
thereof are appropriately performed.
[0158] It is to be understood that the phraseology or terminology
used herein is for the purpose of description and not of
limitation. The breadth and scope of the present disclosure should
not be limited by any of the above-described exemplary embodiments,
but should be defined in accordance with the following claims and
their equivalents.
* * * * *