U.S. patent application number 14/052380 was filed with the patent office on 2015-04-16 for method to sustain minimum required aspect ratios of diamond grinding blades throughout service lifetime.
This patent application is currently assigned to HGST NETHERLANDS B.V.. The applicant listed for this patent is HGST Netherlands B.V.. Invention is credited to Jacey R. BEAUCAGE, Christian R. BONHOTE, Trevor W. OLSON.
Application Number | 20150105006 14/052380 |
Document ID | / |
Family ID | 52810060 |
Filed Date | 2015-04-16 |
United States Patent
Application |
20150105006 |
Kind Code |
A1 |
BEAUCAGE; Jacey R. ; et
al. |
April 16, 2015 |
METHOD TO SUSTAIN MINIMUM REQUIRED ASPECT RATIOS OF DIAMOND
GRINDING BLADES THROUGHOUT SERVICE LIFETIME
Abstract
Embodiments of the present invention generally relate to a blade
for isolating devices within a wafer and the method of isolating.
The blade has a core material, a cutting material disposed on the
core material, and a plating material covering a portion of the
core and cutting materials. The edge of the blade is not covered by
the plating material. During operation, a portion of the plating
material is removed to expose the underlying core and cutting
materials based on the wearing of the core and cutting materials at
the edge of the blade.
Inventors: |
BEAUCAGE; Jacey R.; (San
Jose, CA) ; BONHOTE; Christian R.; (Sunnyvale,
CA) ; OLSON; Trevor W.; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HGST Netherlands B.V. |
Amsterdam |
|
NL |
|
|
Assignee: |
HGST NETHERLANDS B.V.
Amsterdam
NL
|
Family ID: |
52810060 |
Appl. No.: |
14/052380 |
Filed: |
October 11, 2013 |
Current U.S.
Class: |
451/541 ;
51/307 |
Current CPC
Class: |
B24D 3/34 20130101; B24D
18/00 20130101; B24D 5/12 20130101 |
Class at
Publication: |
451/541 ;
51/307 |
International
Class: |
B24D 5/12 20060101
B24D005/12; B24D 18/00 20060101 B24D018/00; B24D 3/34 20060101
B24D003/34 |
Claims
1. A blade for isolating devices, comprising: a core material
including a center and a first diameter; a cutting material
disposed on the core material; and a plating material disposed on a
portion of the core material and the cutting material, wherein the
plating material shares a same center with the core material and
has a second diameter that is less than the first diameter.
2. The blade of claim 1, wherein the core material is formed of a
metal.
3. The blade of claim 2, wherein the cutting material is formed of
diamond particles.
4. The blade of claim 3, wherein the plating material is formed of
a same material as the core material.
5. The blade of claim 1, wherein a difference between the first
diameter and the second diameter is about 1.25 mm.
6. The blade of claim 5, wherein the core material has a thickness
of about 70 .mu.m.
7. The blade of claim 6, wherein the plating material has a
thickness of about 200 .mu.m.
8. The blade of claim 5, wherein the core material has a thickness
of about 50 .mu.m.
9. A blade assembly for isolating devices, comprising: a spindle
hub; and a blade coupled to the spindle hub, wherein the blade
including: a core material having a center and a first diameter; a
cutting material disposed on the core material; and a plating
material disposed on a portion of the core material and the cutting
material, wherein the plating material shares a same center and a
second diameter that is less than the first diameter.
10. The blade assembly of claim 9, wherein the core material is
formed of a metal.
11. The blade assembly of claim 10, wherein the cutting material is
formed of diamond particles.
12. The blade assembly of claim 11, wherein the plating material is
formed of nickel.
13. The blade assembly of claim 9, wherein a difference between the
first diameter and the second diameter is about 1.25 mm.
14. The blade assembly of claim 13, wherein the core material has a
thickness of about 70 .mu.m.
15. The blade assembly of claim 14, wherein the plating material
has a thickness of about 200 .mu.m.
16. The blade assembly of claim 13, wherein the core material has a
thickness of about 50 .mu.m.
17. A method for making a blade, comprising: depositing a cutting
material on two sides of a core material; depositing a plating
material on the two sides of the core material, wherein the plating
material covers the core and the cutting materials; and removing a
portion of the plating material to expose underlying cutting and
core materials.
18. The method of claim 17, wherein the plating material is formed
of a same material as the core material.
19. The method of claim 18, wherein the removal of the portion of
the plating material is performed with a dressing stick.
20. The method of claim 19, wherein the dressing stick is formed of
aluminum oxide.
Description
BACKGROUND
[0001] 1. Field
[0002] Embodiments of the present invention generally relate to
semiconductor device fabrication, and more particularly, to a blade
for dicing substrates.
[0003] 2. Description of the Related Art
[0004] Die separation, or dicing, by sawing is the process of
cutting a thin film microelectronic substrate into individual
devices, such as sliders containing read/write recording devices,
with a rotating abrasive saw blade. Dicing by sawing provides
versatility in selection of depth and width (kerf) of cut, as well
as selection of surface finish, and can be used to saw either
partially or completely through a substrate or wafer. Wafer dicing
technology has progressed rapidly, and dicing is now commonly used
in most front-end thin film packaging operations. Dicing is used
extensively for separation of die on thin film integrated circuit
wafers.
[0005] A wafer's device density is ever increasing to reduce unit
costs. As a result of device density increase within a wafer, the
channels between devices are continually decreasing. This
decreasing in spacing demands that saw blade thickness be reduced.
Blades are typically installed into hubs/arbors which support the
blade with precision flatness and concentricity. The protrusion of
the blade from the support of the hub is used to perform the
cutting. The unsupported portion of the blade exposed for cutting
dictates the aspect ratio of the blade, which equals to unsupported
blade exposure divided by blade thickness. With the constant blade
exposure, as the blade thickness decreases, the aspect ratio
increases. The larger the aspect ratio of a blade is, the more the
stiffness and cutting control degrade. Cutting with a high aspect
ratio blade results in reduced cutting performance due to the lower
effective blade stiffness and increased vibration.
[0006] Therefore, an improved blade is needed.
SUMMARY OF THE INVENTION
[0007] Embodiments of the present invention generally relate to a
blade for isolating devices within a wafer and the method of
isolating. The blade has a core material, a cutting material
disposed on the core material, and a plating material covering a
portion of the core and cutting materials. The edge of the blade is
not covered by the plating material. During operation, a portion of
the plating material is removed to expose the underlying core and
cutting materials based on the wearing of the core and cutting
materials at the edge of the blade.
[0008] In one embodiment, a blade for isolating devices is
disclosed. The blade comprises a core material having a center and
a first diameter, a cutting material disposed on the core material,
and a plating material disposed on a portion of the core material
and the cutting material. The plating material shares a same center
with the core material and has a second diameter that is less than
the first diameter.
[0009] In another embodiment, a blade assembly for isolating
devices is disclosed. The blade assembly comprises a spindle hub
and a blade coupled to the spindle hub. The blade comprises a core
material having a center and a first diameter, a cutting material
disposed on the core material, and a plating material disposed on a
portion of the core material and the cutting material. The plating
material shares a same center with the core material and has a
second diameter that is less than the first diameter.
[0010] In another embodiment, a method for making a blade is
disclosed. The method comprises depositing a cutting material on
two sides of a core material, and depositing a plating material on
the two sides of the core material. The plating material covers the
core and the cutting materials. The method further comprises
removing a portion of the plating material to expose underlying
cutting and core materials.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0012] FIG. 1 is a plan view of a blade according to one embodiment
of the invention.
[0013] FIG. 2 is an exploded view of the blade according to one
embodiment of the invention.
[0014] FIG. 3 is a cross sectional view of a blade assembly
according to one embodiment of the invention.
[0015] FIG. 4 illustrates a processing sequence of making the blade
according to one embodiment of the invention.
[0016] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0017] In the following, reference is made to embodiments of the
invention. However, it should be understood that the invention is
not limited to specific described embodiments. Instead, any
combination of the following features and elements, whether related
to different embodiments or not, is contemplated to implement and
practice the invention. Furthermore, although embodiments of the
invention may achieve advantages over other possible solutions
and/or over the prior art, whether or not a particular advantage is
achieved by a given embodiment is not limiting of the invention.
Thus, the following aspects, features, embodiments and advantages
are merely illustrative and are not considered elements or
limitations of the appended claims except where explicitly recited
in a claim(s). Likewise, reference to "the invention" shall not be
construed as a generalization of any inventive subject matter
disclosed herein and shall not be considered to be an element or
limitation of the appended claims except where explicitly recited
in a claim(s).
[0018] Embodiments of the present invention generally relate to a
blade for isolating devices within a wafer and the method of
isolating. The blade has a core material, a cutting material
disposed on the core material, and a plating material covering a
portion of the core and cutting materials. The edge of the blade is
not covered by the plating material. During operation, a portion of
the plating material is removed to expose the underlying core and
cutting materials based on the wearing of the core and cutting
materials at the edge of the blade.
[0019] FIG. 1 is a plan view of a blade 100 according to one
embodiment of the invention. As shown in FIG. 1, the blade 100
includes a core material 102, a cutting material 104 and a plating
material 108. A hole 110 is disposed in the center of the core
material 102 and the plating material 108. The core material 102
may be a metal such as steel or nickel, or may be a composite
material, and the cutting material 104 may be particles of hard
crystals such as diamond or cerium oxide. The cutting material 104
is bonded to the core material 102 by any suitable bonding method,
such as metal bonding or resin bonding. The plating material 108
may be a material that wears at a slower rate than the core
material 102 having the cutting material 104 bonded thereon. In one
embodiment, the plating material 108 is the same material as the
core material 102. Once plated, the core material 102 may wear much
slower than the plating material 108 even if materials are the same
because the cutting material 104 is a reinforcing phase in the
metal matrix of the blade. In one embodiment, both the core and
plating materials are a metal such as nickel. The plating material
108 does not cover the entire core material 102 and cutting
material 104. The edge of the blade 100 is not covered by the
plating material 108, thus the core material 102 and the cutting
material 104 at the edge of the blade 100 are exposed. This exposed
portion of the core material 102 and the cutting material 104 is
the cutting portion 112. The hole 110 is for securing the blade 100
to a blade assembly. The blade 100, the core material 102 and the
plating material 108 as shown in FIG. 1 are all circular, but the
shape is not limited to circular.
[0020] FIG. 2 is an exploded view of the blade 100 according to one
embodiment of the invention. The cutting material 104 may be
disposed on a portion 202 of the core material 102. The portion 202
extends from the edge of the core material 102 to an inner circle
204. The cutting material 104 is not disposed in the area within
the inner circle 204. The size of the inner circle 204 depends on
the securing device of a blade assembly. When the blade 100 is
placed in a blade assembly, the securing device covers the area
within the inner circle 204, thus the cutting material 104 is not
covered by the securing device. The plating material 108 may have
the same center as the core material 102, which is the hole 110.
The plating material 108 may have a smaller diameter than the core
material 102, thus the edge of the core material 102 having the
cutting material 104 disposed thereon is not covered by the plating
material 108.
[0021] As the device density increases within a wafer, the channels
between devices are getting smaller which leads to thinner cutting
portion of saw blades. As the cutting portion 112 gets thinner, the
blade aspect ratio increases if the blade exposure, indicated as
"D" in FIG. 1, remains constant. Beyond an aspect ratio of 30,
significant degradation in performance such as increased chips and
cracks, increased skew and reduced mean targeting may be observed.
The blade exposure may have a minimum length due to several factors
such as thickness of the wafer, minimum clearance between the wafer
and the blade, and minimum undercut. In addition, the blade
exposure may be reduced during operation as a result of wearing of
the cutting portion 112. Thus, a blade having the minimum blade
exposure may be changed out often, leading to an increase in
cost.
[0022] To maintain a low aspect ratio while increase the service
time of the blade, the plating material 108 is deposited on both
sides of the core material 102 covering a portion of both the core
material 102 and the cutting material 104. The plating material 108
may be much thicker than the core material 102, thus providing
support and desired stiffness. Conventional blade support such as
spacers may not be needed as a result. During operation, a portion
of the plating material 108 may be removed to expose the underlying
core material 102 and cutting material 104 as the blade exposure
decreases due to wearing. The portion of the plating material 108
may be removed as a result of contacting the material that is being
cut, or may be removed by a dressing stick, such as an aluminum
oxide stick. The wearable plating material 108 provides support for
the thin cutting portion 112 and provides a way to control the
blade exposure. The blade exposure may be maintained at a minimum
length, leading to a low aspect ratio.
[0023] In one embodiment, the thickness (into the paper) of the
cutting portion 112 is about 50 to 70 micrometers (.mu.m) and the
thickness (into the paper) of the plating material 108 is over 200
.mu.m, so the thickness of the blade 100 at an area with the
plating material 108 is over 250 .mu.m. In one embodiment, the
blade exposure is about 1.25 mm and the thickness of the cutting
portion 112 is about 50 .mu.m, which leads to an aspect ratio of
25. In another embodiment, the blade exposure is about 1.25 mm and
the thickness of the cutting portion is about 70 .mu.m, which leads
to an aspect ratio of 17.9. Both embodiments provide a blade having
an aspect ratio of less than 30.
[0024] FIG. 3 is a cross sectional view of a blade assembly 300
incorporating the blade 100 according to one embodiment of the
invention. The blade 100 is secured to the blade assembly 300 by a
spindle hub 302. The blade 100 has the cutting portion 112
including the core material 102 and the cutting material 104 (not
shown) and the plating material 108.
[0025] FIG. 4 illustrates a processing sequence 400 for making the
blade 100 according to one embodiment of the invention. The
processing sequence 400 starts with step 402, which is depositing a
cutting material on a core material. The core material may be a
circular disk and the cutting material is deposited on both sides
of the core material. The core material may be a metal such as
steel or nickel, or may be a composite material, and the cutting
material may be particles of hard crystals such as diamond or
cerium oxide. The cutting material is bonded to the core material
by any suitable bonding method, such as metal bonding or resin
bonding. The thickness of the core material is based on the width
of the channels between devices located on a wafer. In one
embodiment, the core material may have a thickness of about 50-70
.mu.m.
[0026] Next, at step 404, a plating material is deposited on the
core and cutting materials. The plating material covers both sides
of the core material and the cutting material deposited on the core
material. The plating material may be a material that has good
adhesion to the core material and has a slower wearing rate
compared to the base material reinforced by the cutting material.
In one embodiment, the plating material is the same as the base
material. The plating material on both sides of the core material
may have a combined thickness that is much greater than the
thickness of the core material. The thick plating material provides
support and desired stiffness, thus, conventional blade support
such as spacers are not needed. In one embodiment, the plating
material on both sides of the core material has a combined
thickness of over 200 .mu.m.
[0027] Next, at step 406, a portion of the plating material at the
edge of the blade is removed to expose the underlying core and
cutting materials. The removal process may be achieved by any
conventional removing process, such as dressing by an aluminum
oxide stick. During operation, a portion of the plating material
may be further removed to expose the underlying core and cutting
materials, as the core and cutting materials at the edge are worn
off. The removal of the portion of the plating material during
operation may be achieved by dressing or by contacting the plating
material with the material being cut. The portion of the plating
material may be removed after a single cut or after multiple
cuts.
[0028] In summary, a blade having a plating material covering a
portion of the core and cutting materials is disclosed. The thick
plating material provides support for the blade and provides
desired mechanical stiffness. The wearable plating material
provides a way to maintain a low aspect ratio while increase the
service time of the blade.
[0029] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *