U.S. patent application number 11/292938 was filed with the patent office on 2007-06-07 for electroplated abrasive tools, methods, and molds.
Invention is credited to Chien-Min Sung.
Application Number | 20070128994 11/292938 |
Document ID | / |
Family ID | 38119418 |
Filed Date | 2007-06-07 |
United States Patent
Application |
20070128994 |
Kind Code |
A1 |
Sung; Chien-Min |
June 7, 2007 |
Electroplated abrasive tools, methods, and molds
Abstract
The present invention provides for a mold that can position and
hold abrasive particles, which are to be electrolytically attached
to an electrically conductive substrate during an electrolytic
process. The mold can include an insulating material with a molding
surface suitable for holding the abrasive particles in place during
this process. Additionally, a method for making an abrasive tool
using such a mold is provided, as well as abrasive tools made
thereby. In one aspect of this invention, abrasive tools can have
abrasive particle tips that are arranged in accordance with a
predetermined vertical pattern and/or a predetermined horizontal
pattern in a manner that requires little or no post
electrodeposition processing.
Inventors: |
Sung; Chien-Min; (Taipei
County, TW) |
Correspondence
Address: |
THORPE NORTH & WESTERN, LLP.
8180 SOUTH 700 EAST, SUITE 200
SANDY
UT
84070
US
|
Family ID: |
38119418 |
Appl. No.: |
11/292938 |
Filed: |
December 2, 2005 |
Current U.S.
Class: |
451/540 |
Current CPC
Class: |
B24D 18/0018 20130101;
B24D 18/0009 20130101 |
Class at
Publication: |
451/540 |
International
Class: |
B24B 7/16 20060101
B24B007/16 |
Claims
1. A mold for positioning and holding abrasive particles to be
electrolytically attached to an electrically conductive substrate
during an electrolytic process, comprising: an insulating material
having a molding surface suitable for holding the abrasive
particles in place during electrolytic deposition of a material
that attaches said particles to the electrically conductive
substrate.
2. The mold of claim 1, further comprising an adhesive material
adhered to the molding surface in order to hold the abrasive
particles in place.
3. The mold of claim 1, wherein the insulating material has at
least one aperture extending therethrough which allows circulation
of an electrolytic fluid from an area outside the mold through the
mold and to the molding surface.
4. The mold of claim 3, further comprising a plurality of apertures
extending through the insulating material.
5. The mold of claim 4, wherein the plurality of apertures is
arranged according to a predetermined pattern.
6. The mold of claim 5, wherein the predetermined pattern is a
lattice.
7. The mold of claim 1, wherein the molding surface has a shape
that is inverse to a vertical pattern to be imparted to the
abrasive particles.
8. The mold of claim 7, wherein the molding surface is
substantially flat.
9. The mold of claim 7, wherein the molding surface is concave.
10. The mold of claim 9, wherein the concave shape has a slope of
about 1/1000.
11. The mold of claim 7, wherein the molding surface is convex.
12. The mold of claim 7, wherein the molding surface includes both
convex and concave portions.
13. The mold of claim 1, wherein the molding surface holds the
abrasive particles according to a predetermined horizontal
pattern.
14. The mold of claim 13, wherein the pattern is a lattice
pattern.
15. The mold of claim 5, wherein the molding surface holds the
abrasive particles according to a predetermined pattern that is
complimentary with the pattern of apertures.
16. The mold of claim 15, wherein the pattern of abrasive particles
and the pattern of apertures are each lattice patterns.
17. The mold of claim 13, wherein the pattern provides for at least
one specified area on the molding surface having a higher
concentration of abrasive particles than a remainder of the molding
surface.
18. The mold of claim 1, wherein the insulating material comprises
a resin material.
19. The mold of claim 18, wherein the resin is a synthetic
resin.
20. The mold of claim 18, wherein the resin material includes a
polymeric material.
21. The mold of claim 18, wherein the resin material is a member
selected from the group consisting of: epoxies, lacquers,
varnishes, acrylic polymers, epoxies, and mixtures thereof.
22. The mold of claim 21, wherein the insulating material is a
varnish.
23. The mold of claim 21, wherein the insulating material is an
acrylic polymer.
24. The mold of claim 1, wherein the insulating material is a
rubber material.
25. The mold of claim 24, wherein the rubber material is rubber is
either a natural rubber or a synthetic rubber.
26. A method for making a tool having a plurality of abrasive
particles coupled to a substrate by an electrodeposited material,
comprising: temporarily securing the plurality of abrasive
particles to a molding surface of a mold as recited in claim 1;
positioning the mold in an electrodeposition chamber with the
molding surface oriented toward a substrate to which the abrasive
particles are to be electrolytically attached; electrolytically
attaching the abrasive particles to the substrate with an
electrodeposited material; and removing the mold.
27. The method of claim 26, wherein the substrate comprises an
electrically conductive material.
28. The method of claim 27, wherein the electrically conductive
material is stainless steel.
29. The method of claim 26, wherein the substrate is a tool
body.
30. The method of claim 26, further comprising the step of removing
the substrate from the electrodeposition chamber and attaching the
substrate to a tool body.
31. The method of claim 26, wherein the electrodeposited material
is a metallic material.
32. The method of claim 26, wherein the metallic material is a
metallic composite material.
33. The method of claim 32, wherein the metallic composite material
includes at least one member selected from the group consisting of:
nickel, chromium, copper, titanium, tungsten, tin, iron, silver,
gold, manganese, magnesium, zinc, aluminum, tantalum, alloys
thereof, and mixtures thereof.
34. The method of claim 33, wherein the metallic composite material
includes nickel.
35. The method of claim 31, wherein the metallic material consists
of a metal.
36. The method of claim 35, wherein the metal is a member selected
from the group consisting of: : nickel, chromium, copper, titanium,
tungsten, tin, iron, silver, gold, manganese, magnesium, zinc,
aluminum, tantalum, alloys thereof, and mixtures thereof.
37. The method of claim 36, wherein the metal is nickel.
38. A tool produced by the method of claim 26, comprising: a
substrate having a plurality of abrasive particles coupled to the
substrate by an electrodeposited material, said plurality of
abrasive particles having tips arranged in accordance with a
predetermined vertical pattern and having a portion exposed above
the electrodeposited material which has never been covered by the
electrodeposited material.
39. The tool of claim 38, wherein the vertical pattern is a uniform
height above the substrate.
40. The tool of claim 38, wherein the vertical pattern is a convex
pattern.
41. The tool of claim 38, wherein the vertical pattern is a concave
pattern.
42. The tool of claim 38, wherein the vertical pattern includes
both convex and concave areas.
43. The tool of claim 38, wherein the plurality of abrasive
particles are further arranged according to a predetermined
horizontal pattern.
44. The tool of claim 43, wherein the horizontal pattern is a
lattice.
45. The tool of claim 43, wherein the horizontal pattern provides
for a higher concentration of abrasive particles coupled to a
specified area of the substrate than to a remainder of the
substrate.
46. The tool of claim 36, wherein the electrodeposition of the
electrodeposited material provides a finished working surface
without any post electrodeposition processing.
47. An abrasive tool comprising: a substrate having a plurality of
abrasive particles coupled thereto by an electrodeposited material,
said abrasive particles being arranged according to a predetermined
horizontal pattern, and having exposed portions extending above the
electrodeposited material according to a predetermined vertical
pattern, said electrodeposited material providing a working surface
prepared by the electrodeposition process.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to electroplated
abrasive tools and methods and molds for making electroplated
abrasive tools. Accordingly, the present invention involves the
fields of electrochemistry, materials science, and physics.
BACKGROUND OF THE INVENTION
[0002] Abrasive tools have long been used in numerous applications,
including the cutting, drilling, sawing, grinding, lapping, and
polishing of materials. One common form of an abrasive tool is one
that uses abrasive particles on a tool substrate to perform the
cutting, grinding, polishing, etc.
[0003] Superabrasive particles, such as diamond, polycrystalline
diamond (PCD), cubic boron nitride (CBN), and polycrystalline cubic
boron nitride (PCBN) have been widely used for many materials
removal applications due to their extreme hardness, atomic density,
and high thermal conductivity. For example, dressing disks,
grinding disks, saw blades, wire saws, and drill bits have all
included superabrasive particles attached to a substrate.
[0004] Despite their apparent advantages, a number of issues
continue to hamper the performance and usable life of many known
superabrasive tools. For example, superabrasive particle placement
and retention remain problematic. One additional issue is the
height to which a superabrasive particle extends above the tool
substrate. For many applications, it is advantageous to have all
particles extend to a substantially uniform height above the tool
substrate. In many instances, uniform particle height can help
evenly distribute workload on the particles and therefor help
improve particle retention. In other cases, it may be advantageous
to have the particles extend to varying heights above the tools
substrate according to a predetermined vertical pattern.
[0005] Many methods have been employed for the fabrication of
superabrasive tools, such as brazing, hot pressing, infiltration,
and electroplating among others. However, most of such methods are
unable to produce a tool with the above-recited superabrasive
particle placement characteristics. Further, tools made by most
known methods require post fabrication processing in order to
obtain a working surface with suitable characteristics, such as
proper particle exposure.
[0006] As a result, abrasive tools and methods for making abrasive
tools which allow accurate horizontal and vertical placement of
abrasive particles, and that can achieve a suitable working surface
with little or no post fabrication processing continue to be
sought.
SUMMARY OF THE INVENTION
[0007] Accordingly, the present invention provides abrasive tools
having particles arranged according to both vertical and horizontal
patterns, and which require little or no post production
processing, as well as methods for the manufacture and use thereof.
The present invention additionally provides devices for use as a
part of such manufacturing processes.
[0008] In one aspect, the present invention provides a mold for the
positioning and holding of abrasive particles, which are to be
electrolytically attached to an electrically conductive substrate
during an electrolytic process. The mold may include, or be made of
an insulating material that has a molding surface suitable for
holding the abrasive particles in place during the electrolytic
deposition of a material that attaches the particles to the
electrically conductive substrate.
[0009] In another aspect, methods are provided for making a tool
that has a plurality of abrasive particles coupled to a substrate
by an electrodeposited material. The method may include the steps
of: 1) temporarily securing the plurality of abrasive particles to
a molding surface of a mold, such as the molds described herein, 2)
positioning the mold in an electrodeposition chamber with the
molding surface oriented toward a substrate to which the abrasive
particles are to be electrolytically attached, 3) electrolytically
attaching the abrasive particles to the substrate with an
electrodeposited material, and 4) removing the mold.
[0010] In yet another aspect, the present invention includes
abrasive tools that, in some aspects, can be produced by the
methods recited herein. Such tools generally include a substrate
having a plurality of abrasive particles that are coupled to the
substrate by an electrodeposited material. This plurality of
abrasive particles can have tips arranged in accordance with a
predetermined vertical pattern.
[0011] The above-recited features and advantages of the present
invention will become apparent from a consideration of the
following detailed description presented in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1a through 1h are various views showing a series of
steps for making a tool in accordance with an embodiment of this
invention;
[0013] FIG. 1a is a bottom view of a mold in accordance with an
embodiment of this invention showing a molding surface of the
mold;
[0014] FIG. 1b is a sectional view taken along line A-A of FIG. 1a
in accordance with an embodiment of this invention;
[0015] FIG. 1c is the sectional view of FIG. 1b showing an adhesive
coating on a molding surface of the mold in accordance with an
embodiment of this invention;
[0016] FIG. 1d is a bottom view of a mold showing placement of
abrasive particles on the molding surface in accordance with an
embodiment of this invention;
[0017] FIG. 1e is the sectional view of FIG. 1c showing placement
of abrasive particles on the molding surface in accordance with an
embodiment of this invention;
[0018] FIG. 1f is a partial, sectional view of an electrodeposition
chamber showing the orientation of a tool substrate and a mold in
accordance with an embodiment of this invention;
[0019] FIG. 1g is the partial, sectional view of FIG. 1f showing
abrasive particles coupled to the tool substrate by an
electrodeposited material in accordance with an embodiment of this
invention;
[0020] FIG. 1h is a sectional view of a tool in accordance with an
embodiment of this invention;
[0021] FIGS. 2a through 2c are various views showing a series of
steps for making a tool in accordance with another embodiment of
this invention;
[0022] FIG. 2a is a sectional view of a mold showing placement of
abrasive particles on the molding surface in accordance with
another embodiment of this invention;
[0023] FIG. 2b is the sectional view of FIG. 2a showing a tool
substrate and abrasive particles coupled thereto by an
electrodeposited material in accordance with another embodiment of
this invention;
[0024] FIG. 2c is a sectional view of a tool in accordance with
another embodiment of this invention.
[0025] The above figures are provided for illustrative purposes
only. It should be noted that actual dimensions of layers and
features may differ from those shown.
DETAILED DESCRIPTION
[0026] Before the present invention is disclosed and described, it
is to be understood that this invention is not limited to the
particular structures, process steps, or materials disclosed
herein, but is extended to equivalents thereof as would be
recognized by those ordinarily skilled in the relevant arts. It
should also be understood that terminology employed herein is used
for the purpose of describing particular embodiments only and is
not intended to be limiting.
[0027] The singular forms "a," "an," and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "an abrasive particle" includes reference to
one or more of such particles.
Definitions
[0028] In describing and claiming the present invention, the
following terminology will be used in accordance with the
definitions set forth below.
[0029] As used herein, "insulating material" refers to a material
or materials used to form a mold in a manner the effectively
prevents accumulation of electrodeposited material on a molding
surface of the insulating material. As explained herein, the
insulating material may include electrically nonconductive and/or
conductive materials.
[0030] As used herein, "molding surface" refers to a surface on the
insulating material to which abrasive particles can be secured.
[0031] As used herein, "predetermined pattern" refers to a
non-random arrangement of either abrasive particles or apertures
that can be determined prior to fabrication of a tool or device
including such particles or apertures.
[0032] As used herein, "horizontal pattern" refers to an
arrangement of either abrasive particles or apertures across a
surface to which they are, or are to be, attached or placed.
[0033] As used herein, "vertical pattern" refers to an arrangement
of heights to which, the exposed tips of abrasive particles extend
above the working surface of a tool or tool substrate.
[0034] As used herein, "working surface" refers to the surface of a
tool or tool substrate that, during operation, faces toward, or
comes in contact with a work piece that is being polished, grinded,
sanded, etc.
[0035] As used herein, "lattice" refers to a horizontal pattern in
which the abrasive particles are equidistant from neighboring
abrasive particles or, in the case of apertures, the apertures are
equidistant from neighboring apertures.
[0036] As used herein, "post electrodeposition processing" refers
to the dressing or grinding required in some conventional methods
to expose the working surface of a tool.
[0037] As used herein, "holding" or "temporarily securing" refers
to the coupling or supporting of particles in order to prevent the
particles from falling from and/or moving on the surface to which
they are coupled or supported. For example, in some embodiments,
gravity may be sufficient to couple or support the particles to the
surface.
[0038] As used herein, "template" refers to a device with a
plurality of apertures used for positioning abrasive particles onto
a mold in a predetermined pattern. The predetermined pattern can be
controlled by the configuration of the apertures on the template.
In use, one side of the template is positioned against the molding
surface of a mold, and diamond particles are spread over the other
side. The apertures can be designed so that only one particle will
fit in each aperture and fall through to contact the molding
surface. The apertures can also be designed so that it accommodates
only particles having a grit size in a specified range. The
particles in the apertures can contact the molding surface so that
they can be secured thereto. The remaining unsecured particles can
be removed. The template can then be removed from the mold.
[0039] As used herein with respect to an identified property or
circumstance, "substantially" refers to a degree of deviation that
is sufficiently small so as to not measurably detract from the
identified property or circumstance.
[0040] As used herein in connection with individual numerical
numbers or numerical ranges, the term "about" refers to an actual
number or range that is slightly above or below the actual value(s)
articulated.
[0041] As used herein, a plurality of items, structural elements,
compositional elements, and/or materials may be presented in a
common list for convenience. However, these lists should be
construed as though each member of the list is individually
identified as a separate and unique member. Thus, no individual
member of such list should be construed as a de facto equivalent of
any other member of the same list solely based on their
presentation in a common group without indications to the
contrary.
[0042] Concentrations, amounts, and other numerical data may be
expressed or presented herein in a range format. It is to be
understood that such a range format is used merely for convenience
and brevity and thus should be interpreted flexibly to include not
only the numerical values explicitly recited as the limits of the
range, but also to include all the individual numerical values or
sub-ranges encompassed within that range as if each numerical value
and sub-range is explicitly recited. As an illustration, a
numerical range of "about 1 to about 5" should be interpreted to
include not only the explicitly recited values of about 1 to about
5, but also include individual values and sub-ranges within the
indicated range. Thus, included in this numerical range are
individual values such as 2, 3, and 4 and sub-ranges such as from
1-3, from 2-4, and from 3-5, etc.
[0043] This same principle applies to ranges reciting only one
numerical value. Furthermore, such an interpretation should apply
regardless of the breadth of the range or the characteristics being
described.
The Invention
[0044] The present invention encompasses electrodeposition methods
of making abrasive tools that allow greater control in the
arrangement and securing of abrasive particles according to both
vertical and horizontal patterns on a tool substrate, and that
require little or no post electrodeposition processing of the
working surface of the tool. In other words, the working surface
results from the electrodeposition process itself. Applicant has
also developed a mold for use with this method as well as abrasive
tools produced by this method.
[0045] Referring to FIGS. 1a through 1e, a mold 10 in accordance
with the present invention is shown. The mold may be used in an
electrolytic process for the positioning and holding of abrasive
particles 22 to the molding surface 18 of the mold. FIGS. 1f
through 1h show the mold configured for use in a partial view of an
electrodeposition chamber 100 in accordance with an embodiment of
this invention. Similarly, FIGS. 2a through 2c show other examples
of a mold configured for use in accordance with an embodiment of
the invention.
[0046] As shown in the Figures, the mold 10 includes an insulating
material 14. This insulating material can effectively prevent the
accumulation of electrodeposited material 58 on the molding surface
18. In the examples shown in FIGS. 1f through 1h and FIGS. 2a
through 2c, the tips 42 of the abrasive particles form part of the
working surface 49 of a tool 50, and these tips are held on the
molding surface of the mold during electrodeposition. As such, the
accumulation of electrodeposited material can be prevented from
occurring on the particle tips and the working surface of the
tool.
[0047] In one embodiment, the insulating material 14 has at least
one aperture 26 extending through the insulating material. In
another embodiment, as shown in FIGS. 1a through 1e, the insulating
material has a plurality of apertures extending through the
insulating material. The apertures can allow for circulation of an
electrolytic fluid 30 from an area outside the mold 34 through the
mold 10 and to the surface 56 of the tool substrate 54 in order to
effect electrodeposition of the material used to secure the
abrasive particles to the tool substrate. Such circulation can be
advantageous as it is generally necessary to keep a sufficient
concentration of the ions (not shown) in an electrolytic fluid at
the location of electrodeposition. In the examples shown in FIGS.
1g, 1h, 2b, and 2c, the location of electrodeposition is on the
surface 56 of the tool substrate 54.
[0048] In some embodiments, the plurality of apertures 26 can be
arranged according to a predetermined pattern. For example, the
predetermined pattern can be a lattice as shown in FIGS. 1a and 1d.
A lattice pattern can help evenly distribute the ions of an
electrolytic fluid 30 to the tool substrate 54. An even
distribution of ions helps the electrodeposited material 58 build
evenly across the surface of the tool substrate, which in turn can
help secure abrasive particles 22 with an even amount of
strength.
[0049] In other embodiments, the plurality of apertures 26 can be
arranged in order to cause greater electrodeposition to occur in
specific areas. For example, FIG. 2b shows apertures located at the
concave portions of the mold. A greater number of ions in the
electrolytic fluid 30 may exist near the aperture causing more
electrodeposited material 58 to form at that location.
[0050] The insulating material 14 may be formed in a variety of
ways. In one embodiment, the insulating material can be formed of a
resin material. For example, the resin material can be a synthetic
resin or a polymeric material, such as polyimide. The resin
material may also include epoxies, lacquers, varnishes, acrylic
polymers, or mixtures thereof. In addition, the resin material may
be a rubber material, including natural and synthetic rubbers, such
as styrene-butadiene, polychloroprene elastomers, fluoroelastomers,
ethylene propylene diene, nitrile elastomers such as Buna-N, and
NBR, polysiloxanes, polyisobutylenes, and urethanes.
[0051] In other embodiments, the insulating material 14 may include
electrically conductive components so long as the insulating
material effectively, or substantially, prevents the formation of
electrodeposited material 58 on the molding surface 18. For
example, the insulating material may be a stainless steel substrate
(not shown) covered with an insulating varnish (not shown).
[0052] The insulating material 14 also includes a molding surface
18 suitable for holding the abrasive particles 22 in place during
the electrolytic deposition of a material 58 that attaches the
abrasive particles to the surface 56 of an electrically conductive
substrate 54, e.g. the tool substrate 54. The mold 10 can be
configured for holding abrasive particles, such as diamond
particles, in a variety of ways. For example, an adhesive material
38 can be adhered to the molding surface for holding the abrasive
particles. The use of adhesive material can allow for the
individual placement of abrasive particles. Other methods of
holding the abrasive particles in place may include the forces of
magnetism, friction, gravity, etc. For example, in one embodiment,
the molding surface may include a plurality of grooves into which
the abrasive particles are friction fitted.
[0053] In one embodiment, as shown in FIG. 1e, the abrasive
particles 22 are held so that they contact the molding surface 18
directly. Advantageously, the shape of a vertical pattern 62 to be
imparted to a tool 50 can be controlled by configuring the shape of
the molding surface. For example, as shown well in FIGS. 2a through
2c, the molding surface can be configured to have a shape that is
inverse to a vertical pattern to be imparted to the abrasive
particles on a tool substrate 54.
[0054] As such, the shape of the molding surface 18 can be adapted
to suit many applications for abrasive tools 50. For example, the
molding surface can be substantially flat (as shown in FIGS. 1a
through 1g), concave, or convex, or it can include both convex and
concave portions (as shown in FIGS. 2a and 2b). In another example,
which can be particularly useful for chemical mechanical polishing
(CMP) applications, the concave shape of the molding surface can
have a slope of about 1/1000, or concavity of about 1/1000. This
last example can impart a convex shape with a slope of about 1/1000
to the vertical pattern 62 of a polishing tool, which is often
desired in CMP applications.
[0055] Additionally, in some embodiments where the abrasive
particles 22 directly contact the molding surface 18, the tips 42
of the particles forming part of the working surface 49 of a tool
can be set in a predetermined vertical pattern. This can help
substantially with even dressing and good finish quality of the
object being polished (not shown). Additionally, this can allow for
specific dressing patterns on the object being polished.
[0056] In some embodiments, the molding surface 18 can hold the
abrasive particles 22 in a predetermined horizontal pattern.
Accordingly, the spacing between the particles on the surface 56 of
the tool substrate 54 can be controlled. Such control can provide a
number of advantages. For instance, controlled spacing of the
abrasive particles can result in increased performance by reducing
excessive frictional force (or drag) and heat generation caused
during the polishing process. In some applications, it is desired
to regularly distribute the abrasive particles over the surface of
the tool substrate. For such applications, the molding surface can
hold the abrasive particles in a lattice pattern.
[0057] Various techniques can be used to selectively position
abrasive particles on the molding surface in a predetermined
horizontal pattern. For example, the particles can be individually
placed on the molding surface. Alternatively, a template (as
defined above) can be used to more efficiently place particles on
the molding surface. Other methods can include the use of transfer
tape or other transfer medium, whereby particles are temporarily
placed on the tape in a predetermined horizontal pattern and then
transferred to the molding surface.
[0058] In one embodiment of the invention, the molding surface 18
can hold the abrasive particles 22 according to a predetermined
pattern that is complimentary with the pattern of apertures 26. For
example, both the abrasive particles and the apertures can each be
arranged in lattice patterns as shown in FIG. 1d. Advantageously,
these complimentary patterns can provide for substantially equal
concentrations of ions in the electrolytic fluid 30 to reach the
site of electrodepostion around each abrasive particle. Thus, the
amount of electrodeposited material 58 securing each abrasive
particle can be substantially equivalent. This can help maximize
particle retention by distributing substantially equal work load to
each particle.
[0059] In other embodiments, the molding surface 18 can hold the
abrasive particles 22 in a pattern that provides for at least one
specified area on the molding surface that has a higher
concentration of abrasive particles than the remainder of the
molding surface. This can be particularly useful in CMP
applications. For example, it may be desired to have a higher
concentration of abrasive particles near the perimeter of a
disc-shaped abrasive tool. The perimeter generally spins faster
than the center of the disc-shaped tool and often there is more
pressure on the leading edge of the disc. Additional patterns and
configurations of abrasive particles may be found in Applicant's
co-pending U.S. patent applications having Ser. No. 10/109,531
filed Mar. 27, 2002 and Ser. No. 10/954,956 filed Sep. 29, 2004,
each of which are incorporated herein by reference.
[0060] In another aspect of the invention, a method is provided for
making a tool 50 that has a plurality of abrasive particles 22
coupled to a substrate 54 by an electrodeposited material 58. As an
initial step, abrasive particles can be temporarily secured to a
molding surface 18 of a mold 10, as described herein. Next, the
mold and the secured particles can be positioned into an
electrodeposition chamber 100 with the molding surface oriented
toward the substrate. Electrodeposition of a material on the
surface 56 of the substrate 54 is then performed and the abrasive
particles become electrolytically attached to the substrate with
the electrodeposited material. The mold can then be removed,
revealing a tool, or portion of a tool having abrasive particles
attached to the surface of the tool substrate.
[0061] In one example, abrasive particles 22 can be temporarily
secured to the molding surface 18 of a mold 10 with an adhesive
material 38 as described above. With the molding surface oriented
towards the substrate 54, electrodeposited material 58 can begin to
form on the substrate until a portion of the abrasive particles is
covered. The electrodeposited material can more firmly attach the
particles to the adhesive material, and thus, the mold can be
easily removed revealing the exposed tips of the abrasive
particles.
[0062] In one embodiment, the substrate 54 can be an electrically
conductive material, such as stainless steel. This can allow the
substrate to act as one of the electrodes in the electrolytic
process. The substrate can itself be the tool body (not shown).
Alternatively, the substrate can be later secured to a tool body by
other means.
[0063] In another embodiment of the invention, the electrodeposited
material 58 can be a metallic material, such as a metal or a
metallic composite material. For example, the electrodeposited
material may be metals such as nickel, chromium, copper, titanium,
tungsten, tin, iron, silver, gold, manganese, magnesium, zinc,
aluminum, tantalum, or alloys or mixtures thereof. The metallic
composite material may be a composite that includes one or more of
these metals.
[0064] In another aspect of this invention, a tool 50 produced by
the above-described method is provided. The tool can have a
substrate 54 with a plurality of abrasive particles 22 that are
coupled to the substrate by an electrodeposited material 58. The
abrasive particles can be arranged such that the tips 42 of the
particles have a predetermined vertical pattern. Additionally, the
abrasive particles can have a portion exposed above the
electrodeposited material which has never been covered by the
electrodeposited material
[0065] For example, the abrasive particles 22 can each be set at a
uniform height, or substantially uniform height above the
substrate. The vertical pattern can also be convex, concave, or
include both convex and concave areas.
[0066] In addition, the plurality of abrasive particles 22 can be
arranged on the substrate 54 according to a predetermined
horizontal pattern. For example, the abrasive particles can be
arranged in a lattice as defined above. The abrasive particles can
also be arranged such that there is a higher concentration of
abrasive particles coupled to a specified area of the substrate
than to the remainder of the substrate. Such vertical and
horizontal patterns provide many advantages such as those described
above.
[0067] In another embodiment of the invention, an abrasive tool 50
can be provided for that requires little or no post
electrodeposition processing. In this embodiment, the
electrodeposited material 58 forms on the substrate 54 of the tool,
and does not occur on the finished working surface 49 of the tool.
Because of this, the finished working surface does not require
dressing to expose the tips 42 of the abrasive. particles like some
other conventional methods. This helps prevent damage to the
abrasive particles from the impact of dressing the working surface
of the tool.
EXAMPLES
[0068] For a greater understanding of the present invention,
examples will be provided below. These examples are in no way meant
to serve as a limitation to the scope of the present invention.
Example 1
Manufacture of a CMP Pad Dresser
[0069] A mold of a polyimide layer (1 mm thick) that is stamped to
contain a plurality of apertures arranged in a lattice pattern. The
center of each aperture is separated from the center of neighboring
apertures by a distance of 0.7 mm, and each aperture has a 0.5 mm
diameter. One surface of the polyimide layer (i.e. the molding
surface) is coated with an acrylic adhesive (50 microns thick).
Diamond grits of 100/120 mesh are attached to the molding surface
with each diamond grit located in the center of the four
surrounding apertures. The diamond covered molding surface is
placed against a disc-shaped stainless steel substrate (being 108
mm in diameter by 6.5 mm in thickness). The diamond grits are
between the molding surface and the stainless steel substrate. The
mold and the substrate are located in a plastic (PVC) ring 48 to
hold them together during electrolytic process. The substrate is
placed in contact with a cathode. NiSO.sub.4 solution is used as
the electrolytic fluid. The plastic ring, mold, and substrate are
submerged in the electrolytic fluid inside a PVC layer for sealing
off the electrolytic fluid. Electrolysis is performed causing
electrodeposition of the Ni on the substrate. Electrolysis
continues until the Ni covers approximately about 2/3 of the
average diamond grit size. The polyimide mold is then removed and
the substrate with diamond grits attached by electrodeposited Ni is
recovered.
Example 2
[0070] Thirty molds are made as follows:
[0071] Each mold is formed of a stainless steel disc that is about
120 mm in diameter and about 120 microns in thickness. Each disc is
lithographically etched to form a plurality of apertures thereon
distributed in a lattice pattern as described below. The apertures
cover a generally circular area on a central portion of each disc
of about 100 mm in diameter, leaving a width of about 20 mm around
the perimeter of each disc without any apertures. Measuring from
the approximate center points of adjacent apertures, (the "aperture
separation"), a number of discs are formed with the following
aperture separations:
[0072] 1. Ten discs with an aperture separation of about 800
microns, each aperture about 400 microns in diameter;
[0073] 2. Ten discs with an aperture separation of 600 microns,
each aperture about 300 microns in diameter;
[0074] 3. Ten discs with an aperture separation of 400 microns,
each aperture about 200 microns in diameter.
[0075] Each disc is varnished coated, rubber coated, or otherwise
coated with an inert or insulative material in order to improve its
electrically insulating properties. However, this can be an
optional step in certain applications where a less conductive, or
non-conductive material is used for the mold itself. In some other
cases, when the abrasive particles are insulating (e.g. diamond
particles), the stainless steel, or other electrically conductive
disc can be insulated by its separation from a cathodic substrate
by the intervening insulating particles.
[0076] Using the above molds, the following procedure is used to
make diamond pad conditioners:
[0077] 1. Each mold is coated on both sides with an adhesive layer
and assembled with an abrasive particle template on each side. The
abrasive particle templates have been configured and selected to
properly accommodate abrasive particles of a desired size, and to
allow such particles to adhere between the holes in the mold on
which the template is used (i.e. each aperture in each template
will be placed so as to compensate for the holes in the mold and
ensure that each abrasive particle will be adhered to the surface
of the mold rather than falling through the apertures of the
mold).
[0078] 2. The mold and template assemblies are then fastened
together with one or more dowel pins engaged in pin holes aligned
and extending through each member of each assembly. However, it
should be noted that other mechanisms, such as clamps, adhesives,
etc., can be used in order to hold the templates and the mold
together in an assembly.
[0079] 3. Diamond particles (MBG-660 made by Diamond Innovations)
of the appropriate size are then dispersed into the apertures of
each template so that each template aperture accommodates and
receives only a single abrasive particle which becomes adhered to
the surface of the mold.
[0080] 4. The excess diamonds are discarded by turning over,
vibrating, shaking, etc., each mold/template assembly.
[0081] 5. For each mold, the templates are removed leaving diamond
particles adhered in the pattern dictated by the template on each
surface of the mold. In some cases, the pattern dictated by the
template may result in diamond particles located at the center
between each set of four apertures on the mold.
[0082] 6. Each mold is centered between two stainless steel
substrates that are about 100 mm in diameter and about 6.5 mm in
thickness, such that the diamond particles are sandwiched between
the mold and the substrates. Since the diamond particles generally
vary slightly in size, only some, if any of the larger diamond
particles will contact the substrate.
[0083] 7. For each mold, a heavy steel ring is pressed along the
outer periphery of the mold to make sure that moving, shifting, or
warping does not occur during the electrodeposition process. In
some aspects, the ring may actually bend the periphery of the mold
slightly to create a concave shape on each side of the mold. The
amount of slope in the concavity may be controlled somewhat using
this mechanism, and in some aspects the slope may be about 1/1000.
This will cause the diamond particles on the periphery of the
working surface of the substrate to be slightly lower (about 50
microns) than at the center of the substrate in the finished
tool
[0084] 8. Each of the mold/substrate assemblies is located in holes
of a plastic rack. The bases of the substrates are connected to the
cathode of a plating tank. The mold/substrate assemblies are
covered with a NiSO.sub.4 electrolyte solution (i.e. placed in an
electrolytic solution tank or bath, and as electricity passes
through the substrate, nickel cations are reduced and nickel metal
deposits onto the substrate. As the nickel builds in a layer on the
substrate it grows toward the mold and the diamond particles
attached to the mold eventually become surrounded by and embedded
in the nickel layer to a selected degree. The depth to which the
particles become buried can be controlled by the operator of the
process. In one aspect, the depth of the layer may be from about
1/3 to 2/3 of the distance between the mold and the substrate. The
building of the layer can be accomplished evenly and quickly
because of the fact that the electrolytic solution is allowed to
circulate through the apertures of the mold.
[0085] 9. Since the mold is not electrically charged due to the
intervening insulating diamond particles and the optional varnish
coating or other insulating material, nickel does not deposit on
the mold or the portions of the diamond particles near the molding
surface.
[0086] 10. Once the nickel layer has been completed, the tool and
mold are removed from the electroplating solution and separated to
reveal the working surface of the tool. The mold can then be
reused.
[0087] Because the nickel layer builds from the substrate toward
the mold, and the diamond particles become attached to the
substrate as a result of the growth process, the profile of the
exposed diamond particle tips on the working surface of the final
tool will be dictated by the shape imparted by the molding surface
of the mold. In this way, the diamond particle tips can be arranged
in a predetermined vertical pattern on the working surface of the
finished tool. Further, because of the nature of the process, no
post fabrication finishing or work is required in order to provide
a finished tool. In other words, in some aspects, a final tool
which is ready for use may be produced as soon as the nickel layer
is completed and the tool is removed from the electroplating
bath.
[0088] Of course, it is to be understood that the above-described
examples are only illustrative of the application of the principles
of the present invention. Numerous modifications and alternative
arrangements may be devised by those skilled in the art without
departing from the spirit and scope of the present invention and
the appended claims are intended to cover such modifications and
arrangements. Thus, while the present invention has been described
above with particularity and detail in connection with what is
presently deemed to be the most practical and preferred embodiments
of the invention, it will be apparent to those of ordinary skill in
the art that numerous modifications, including, but not limited to,
variations in size, materials, shape, form, function and manner of
operation, assembly and use may be made without departing from the
principles and concepts set forth herein.
* * * * *