U.S. patent application number 11/296733 was filed with the patent office on 2006-06-15 for conditioner for chemical mechanical planarization pad.
This patent application is currently assigned to EHWA DIAMOND INDUSTRIAL CO., LTD.. Invention is credited to Jung Soo An, Kyoung Kuk Kwack, Joo Han Lee.
Application Number | 20060128288 11/296733 |
Document ID | / |
Family ID | 36584645 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060128288 |
Kind Code |
A1 |
An; Jung Soo ; et
al. |
June 15, 2006 |
Conditioner for chemical mechanical planarization pad
Abstract
The present invention provides a conditioner for CMP pad
required for global planarization of wafer to achieve high
integration of a semiconductor element. The conditioner for CMP pad
includes a metal substrate having abrasive particles fixed thereto,
a plurality of abrasive particles fixed to the metal substrate, and
a layer of metal binder fixing the abrasive particles to the metal
substrate. The abrasive particles include at least one pattern. The
pattern includes at least one row of abrasive particles and the
abrasive particles include bigger abrasive particles and smaller
abrasive particles. In addition, a diameter difference between
smaller and bigger abrasive particles is 10 to 40%. The present
invention ensures uniform dressing of conditioner, superior
dressing efficiency and superior performance reproducibility.
Inventors: |
An; Jung Soo; (Seoul,
KR) ; Lee; Joo Han; (Seoul, KR) ; Kwack;
Kyoung Kuk; (Suwon, KR) |
Correspondence
Address: |
WELLS ST. JOHN P.S.
601 W. FIRST AVENUE, SUITE 1300
SPOKANE
WA
99201
US
|
Assignee: |
EHWA DIAMOND INDUSTRIAL CO.,
LTD.
|
Family ID: |
36584645 |
Appl. No.: |
11/296733 |
Filed: |
December 7, 2005 |
Current U.S.
Class: |
451/444 |
Current CPC
Class: |
B24B 53/12 20130101;
B24B 53/017 20130101 |
Class at
Publication: |
451/444 |
International
Class: |
B24B 21/18 20060101
B24B021/18 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2004 |
KR |
10-2004-105068 |
Claims
1. A conditioner for Chemical Mechanical Planarization (CMP) pad
comprising: a metal substrate having abrasive particles fixed
thereto; a number of abrasive particles fixed to the metal
substrate; and a layer of metal binder fixing the abrasive
particles to the metal substrate, wherein the abrasive particles
have at least one pattern, the pattern including at least one row
of abrasive particles, the abrasive particles including bigger
abrasive particles and smaller abrasive particles, and wherein a
diameter difference between smaller and big abrasive particles is
10 to 40%.
2. The conditioner for CMP pad according to claim 1, wherein the
pattern comprises a row of bigger abrasive particles and a row of
smaller abrasive particles alternately arranged.
3. The conditioner for CMP pad according to claim 1, wherein the
pattern comprises a pattern of bigger abrasive particles and a
pattern of smaller abrasive particles alternately arranged.
4. The conditioner for CMP pad according to claim 1, wherein the
row of abrasive particles comprises bigger abrasive particles and
smaller abrasive particles alternately arranged.
5. The conditioner for CMP pad according to claim 1, wherein the
pattern has two rows of bigger abrasive particles and a row of
smaller abrasive particles alternately arranged.
6. The conditioner for CMP pad according to claim 1 wherein a gap
of abrasive particle rows including at lest one bigger abrasive
particle is 2.5 to 150 times the average diameter of the bigger
abrasive particles.
7. The conditioner for CMP pad according to claim 6, wherein a gap
of the abrasive particle rows is 2.5 to 100 times the average
diameter of the bigger abrasive particles.
8. The conditioner for CMP pad according to claim 1, wherein the
abrasive particles comprise one selected from a group consisting of
super-abrasive particle, cubic boron nitride (CBN) particle and
diamond particle.
9. The conditioner for CMP pad according to claim 6, wherein the
abrasive particles comprise one selected from a group consisting of
super-abrasive particle, cubic boron nitride (CBN) and diamond
particle.
10. A conditioner for Chemical Mechanical Planarization (CMP) pad
comprising: a metal substrate having abrasive particles fixed
thereto; a number of abrasive particles fixed to the metal
substrate; and a layer of metal binder fixing the abrasive
particles to the metal substrate, wherein the abrasive particles
include at least three groups of abrasive particles of different
sizes, respectively, the abrasive particles having at least one
pattern, each pattern including at least one row of abrasive
particles and abrasive particles having at least 3 groups of
abrasive particles, and wherein a diameter difference of abrasive
particles between a group of biggest abrasive particles and a group
of smallest abrasive particles is 10 to 40%.
11. The conditioner for CMP pad according to claim 10, wherein each
of the rows of abrasive particles comprises abrasive particles of
equal size, and the rows are repetitively arranged in the order of
the size of abrasive particles.
12. The conditioner for CMP pad according to claim 10, wherein the
row of abrasive particles comprises abrasive particles including at
least 3 groups of abrasive particles; and is repetitively arranged
by size of the abrasive particles.
13. The conditioner for CMP pad according to claim 10, wherein a
gap of abrasive particle rows including at least one biggest
abrasive particle is 2.5 to 150 times the average diameter of the
biggest abrasive particle.
14. The conditioner for CMP pad according to claim 13, wherein a
gap of abrasive particle rows including at least one biggest
abrasive particle is 2.5 to 100 times the average diameter of the
biggest abrasive particle.
15. The conditioner for CMP pad according to claim 10 wherein the
abrasive particles comprise one selected from a group consisting of
super abrasive particle, cubic boron nitride (CBN) particle and
diamond particle.
16. The conditioner for CMP pad according to claim 13, wherein the
abrasive particles comprise one selected from a group consisting of
super abrasive particle, cubic boron nitride (CBN) and diamond
particle.
17. A conditioner for Chemical Mechanical Planarization (CMP) pad
comprising a plurality of pellets having abrasive particles
arranged thereon, wherein the abrasive particles are patterned as
described in claim 1.
18. The conditioner for CMP pad according to claim 17, wherein the
abrasive particles comprise one selected from a group consisting of
super abrasive particle, cubic boron nitride (CBN) particle and
diamond particle.
19. A conditioner for CMP pad comprising a plurality of pellets
having abrasive particles arranged thereon, wherein the abrasive
particles are patterned as described in claim 10.
20. The conditioner for CMP pad according to claim 19, wherein the
abrasive particles comprise one selected from a group consisting of
super abrasive particle, CBN particle and diamond particle.
Description
CLAIM OF PRIORITY
[0001] This application claims the benefit of Korean Patent
Application No. 2004-105068 filed on Dec. 13, 2004, in the Korean
Intellectual Property Office, the disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a conditioner for Chemical
Mechanical Planarization (CMP) pad required for global
planarization of wafer to achieve high integration of a
semiconductor element. More particularly, the present invention
relates to a conditioner for CMP pad in which the arrangement of
abrasive particles is properly controlled.
[0004] 2. Description of the Related Art
[0005] These days, the semiconductor industry experiences
high-speed and high-integration in circuits, and with integration
capacity enlarged increasingly, chip size becomes bigger. To
overcome the resultant limitations, the industry has undergone
structural changes such as minimized width of wiring, larger
diameter of wafer and multilayered wiring.
[0006] However with higher integration of elements and reduced
minimum width of wiring, the semiconductor industry has encountered
limitations the conventional local planarization technology cannot
overcome. To achieve processing efficiency and high quality,
planarization across wafer or global planarization by Chemical
Mechanical Polishing (CMP) has served as the only solution. Global
planarization by CMP is necessary for the current wafer
process.
[0007] CMP is a polishing process in which semiconductor wafer is
planarized via polishing elimination process and dissolution of
chemical solution at the same time by chemical and mechanical
polishing process.
[0008] For the process, polishing pad and wafer are pressurized,
and placed under relative motion. Slurry mixed with abrasive
particles and chemical solution is provided to the pad. Then,
numerous bubbling pores on a polyurethane polishing pad serve to
contain a new polishing solution. Thereby a certain polishing
efficiency and polishing uniformity across wafer surface can be
attained.
[0009] However, during polishing, pressure and relative speed are
added, and thus with process time passing, the surface of pad
becomes uneven and fine pores on the polishing pad are glazed by
abrasive remnants, no longer capable of playing their role.
[0010] Subsequently, global planarization across wafer surface and
uniform polishing on wafers during the whole process can not be
accomplished.
[0011] To prevent pad from becoming uneven and fine pores from
being glazed, a conditioner is used to finely polish the surface so
as to induce new micro pores to come out.
[0012] A conditioner for CMP pad, as shown in FIG. 1, comprises a
metal substrate 11 including stainless or nickel plate, a number of
abrasive particles 13 fixed to the metal substrate 11, and a layer
of metal binder 12 fixing the abrasive particles 13 to the metal
substrate 11.
[0013] There are many methods for manufacturing a conditioner
capable of finely polishing the pad surface as described above. For
example, electroplating, brazing or sintering is used according to
a method for fixing abrasive particles. Abrasive particles and
super abrasive particles (CBN) are used as abrasive particles.
[0014] A method for arranging abrasive particles on the conditioner
includes a random arrangement in which abrasive particles are
randomly arranged as shown in FIG. 1 and a patterning in which
abrasive particles are arranged in a predetermined position as
shown in FIG. 2.
[0015] Out of the methods of arranging abrasive particles, the
random arrangement, as shown in FIG. 1, does not allow precise
control of the number of abrasive particles 11 which are contained
in a conditioner 10, thus unlikely to achieve reproducibility of
design and performance.
[0016] Furthermore, for the random arrangement, a uniform gap of
abrasive particles cannot be maintained, possibly causing abrasive
particles to be locally biased in the conditioner. In this case, a
pad goes through uneven wear, resultantly deteriorating profile or
uniformity of wafer to be polished.
[0017] Meanwhile out of the methods of arranging abrasive particles
regularly in a predetermined position, as shown in FIG. 2, there is
a known method of arranging abrasive particles 23 in a
predetermined pattern 24 by maintaining a uniform gap of abrasive
particles 23 in consideration of only position of abrasive
particles 23 regardless of size thereof.
[0018] Unlike random arrangement, the regular arrangement as just
described can prevent abrasive particles 23 from being biased. Also
the regular arrangement is more advantageous in terms of
reproducibility of product performance since an equal number of
abrasive particles are arranged for each conditioner 20 and the
abrasive particles can be arranged in the same position.
[0019] In general, bigger abrasive particles and smaller abrasive
particles are mixed in a predetermined ratio in manufacturing the
conditioner.
[0020] Bigger abrasive particles and smaller abrasive particles are
mixed in a predetermined ratio due to the following reason. In case
of using only abrasive particles of a predetermined size,
protrusion height of abrasive particles in the conditioner becomes
uniform, and thus with lessened stress on each abrasive particle,
the abrasive particles can be prevented from falling off. However,
with a significant increase in the number of abrasive particles
being involved in a dressing, the abrasive particles cannot deeply
penetrate the pad, resultantly deteriorating dressing effects.
[0021] But in case of manufacturing the conditioner according to
the conventional patterning method, a predetermined ratio of bigger
and smaller abrasive particles is hardly maintainable. As a result,
the conventional patterning method has limitations in realizing
superior reproducibility.
[0022] Moreover, according to the conventional patterning method,
in case where bigger abrasive particles or relatively smaller
abrasive particles are biased in a certain region, abrasive
particles of a certain region are involved in the dressing, while
those of another region are not, leading to uneven wear of the pad.
As a result, superior profile of wafer may not be obtainable.
SUMMARY OF THE INVENTION
[0023] The present invention has been made to solve the foregoing
problems of the prior art and it is therefore an object of the
present invention to provide a conditioner for CMP pad capable of
achieving uniform dressing and superior dressing efficiency and
performance reproducibility by arranging abrasive particles by
proper size, by proper form and in a proper position, maintaining a
uniform gap without abrasive particles being biased and at the same
time ensuring a desired particle size distribution of abrasive
particles in a predetermined ratio in the conditioner.
[0024] The present invention will be explained hereunder.
[0025] According to an aspect of the invention for realizing the
object, there is provided a conditioner for CMP pad, the
conditioner comprising a metal substrate having abrasive particles
fixed thereto, a number of abrasive particles fixed to the metal
substrate and a layer of metal binder fixing the abrasive particles
to the metal substrate, wherein the abrasive particles have at
least one pattern, the pattern including at least one row of
abrasive particles, the abrasive particles including bigger
abrasive particles and smaller abrasive particles, and wherein a
diameter difference between smaller and bigger abrasive particles
is 10 to 40%.
[0026] According to another aspect of the invention for realizing
the object, there is provided a conditioner for CMP pad, the
conditioner comprising a metal substrate having abrasive particles
fixed thereto, a number of abrasive particles fixed to the metal
substrate, and a layer of metal binder fixing the abrasive
particles to the metal substrate, wherein the abrasive particles
include at least three groups of abrasive particles with different
sizes, respectively, the abrasive particles have at least one
pattern, each pattern including at least one row of abrasive
particles and abrasive particles including at least three groups of
abrasive particles, and wherein a diameter difference of abrasive
particles between a group of biggest abrasive particles and a group
of smallest abrasive particles is 10 to 40%.
[0027] The invention will be explained in greater detail
hereunder.
[0028] According to the invention, there is provided a conditioner
for CMP pad, the conditioner comprising a metal substrate having
abrasive particles fixed thereto, a number of abrasive particles
fixed to the metal substrate, and a layer of metal binder fixing
the abrasive particles to the metal substrate, wherein size of the
abrasive particles is adequately controlled and the abrasive
particles are adequately arranged.
[0029] The conditioner for CMP pad of the invention includes at
least one pattern made of a number of abrasive particles.
[0030] Each pattern includes at least one row of abrasive particles
and the abrasive particles comprise 2 groups of bigger abrasive
particles and smaller abrasive particles.
[0031] A diameter difference between smaller and bigger abrasive
particles is 10 to 40%.
[0032] Bigger abrasive particles are directly involved in pad
dressing, while smaller abrasive particles help slurry and abrasive
remnants move.
[0033] To more clarify the role of bigger abrasive particles and
smaller abrasive particles as described above, a diameter
difference between smaller and bigger abrasive particles should be
10 to 40%.
[0034] Also, according to the invention, the abrasive particles can
be broken down into at least 3 groups of abrasive particles by
size.
[0035] For example, the group of abrasive particles may comprise a
group of bigger abrasive particles, a group of mid-sized abrasive
particles and a group of smaller abrasive particles. Or the group
of abrasive particles may comprise a group of bigger abrasive
particles, a group of mid-sized abrasive particles, a group of
smaller abrasive particles and a group of smallest abrasive
particles.
[0036] Out of the groups of abrasive particles, a diameter
difference of abrasive particle between the group of biggest
abrasive particles and the group of smallest abrasive particles
should be 10 to 40%.
[0037] Relatively bigger abrasive particles are directly involved
in pad dressing while relatively smaller abrasive particles help
slurry and polishing remnants move.
[0038] As described above, to more clarify the role of abrasive
particles by size, a diameter difference of abrasive particles
between the group of biggest abrasive particles and the group of
smallest abrasive particles should be 10 to 40%.
[0039] The present invention is applicable to not only a patterned
conditioner but also an unpatterned conditioner.
[0040] Also, the present invention is not limited to a method for
manufacturing a conditioner but applicable to any of the
manufacturing methods of brazing, electroplating and sintering.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0042] FIG. 1 illustrates a conventional conditioner for Chemical
Mechanical Polishing (CMP) pad having abrasive particles randomly
arranged;
[0043] FIG. 2 illustrates another conventional conditioner for CMP
pad having abrasive particles patterned;
[0044] FIG. 3 is an embodiment of a conditioner for CMP pad of the
invention;
[0045] FIG. 4 is another embodiment of the conditioner for CMP pad
of the invention;
[0046] FIG. 5 is further another embodiment of the conditioner for
CMP pad of the invention;
[0047] FIG. 6 is other embodiment of the conditioner for CMP pad of
the invention;
[0048] FIG. 7 is another embodiment of the conditioner for CMP pad
of the invention;
[0049] FIG. 8 is further another embodiment of the conditioner for
CMP pad of the invention; and
[0050] FIG. 9 is yet another embodiment of the conditioner for CMP
pad of the invention, in which (a) shows a sectional view of the
conditioner, and (b) shows a schematic view of the conditioner.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0051] Preferred embodiments of the present invention will now be
described in detail with reference to the accompanying
drawings.
[0052] FIG. 3 to 5 show preferred embodiments of a conditioner for
CMP pad according to the invention.
[0053] As shown in FIG. 3, a conditioner for Chemical Mechanical
Polishing (CMP) pad 30 includes at least one pattern 34 comprising
a number of abrasive particles 33.
[0054] The pattern 34 includes at least one row of abrasive
particles 331.
[0055] The row of abrasive particles 331 includes a row of bigger
abrasive particles 331a having bigger abrasives 33a and a row of
smaller abrasive particles 331b having smaller abrasive particles
33b.
[0056] The pattern 34 has the row of big abrasive particles 331a
and the row of small abrasive particles 331b alternatively
arranged.
[0057] A diameter difference between the abrasive particles is 10
to 40%, and bigger abrasive particles 33a and smaller abrasive
particles 33b are alternately attached to the conditioner.
[0058] Bigger abrasive particles directly engage in pad dressing,
while smaller abrasive particles help slurry and abrasive remnants
move.
[0059] Meanwhile, in case where bigger abrasive particles or
smaller abrasive particles are biased, each abrasive particle
biased receives fewer loads so that abrasive particles cannot
deeply penetrate the pad.
[0060] Like a conditioner 30 of the invention as shown in FIG. 3,
in case where smaller abrasive particles are arranged around bigger
abrasive particles, bigger abrasive particles, which play a
considerable role in pad dressing, sustain increasing load.
Subsequently, bigger abrasive particles can penetrate the pad more
deeply, enhancing dressing effects and restraining glazing of pad
more effectively.
[0061] Likewise, the conditioner of the invention enables abrasive
particles to maintain a predetermined position in terms of
arrangement of abrasive particles. Further, smaller abrasive
particles which have 10 to 40% of diameter difference from bigger
abrasive particles can be fixed to a certain position. Therefore,
the uneven wear caused by biased bigger or smaller abrasive
particles can be inhibited. In addition, each conditioner product
has abrasive particles attached thereto in a predetermined number
and in a predetermined size, thus efficient to achieve
reproducibility thereof.
[0062] FIG. 4 shows another embodiment of the conditioner of the
invention.
[0063] As shown in FIG. 4, according to the invention, a pattern 44
of the conditioner 40 includes a pattern with bigger abrasive
particles 44a and a pattern with smaller abrasive particles 44b,
both of which are alternately arranged. Thereby abrasive particles
of different sizes are alternately attached to the conditioner,
increasing effects of pad dressing.
[0064] FIG. 5 illustrates yet another embodiment of the conditioner
of the invention.
[0065] As shown in FIG. 5, according to the invention, abrasive
particles of different sizes are alternately arranged
circlewise.
[0066] For arrangement of abrasive particles according to the
invention, a gap of abrasive particle rows including at least one
relatively bigger abrasive particle, which plays a substantial role
in dressing, is preferably 2.5 to 150 times the average diameter of
the bigger abrasive particles, and more preferably 2.5 to 100 times
the average diameter of the bigger abrasive particles. As a result,
superior effects of dressing are attainable.
[0067] If a gap of abrasive particle rows including at least one of
bigger abrasive particles is at least 150 times the average
diameter of the bigger abrasive particles, fewer bigger abrasive
particles engage in dressing, lowering dressing efficiency.
[0068] Abrasive particle rows of FIG. 3 and 4 are made of only
smaller particles or only bigger particles. But the conditioner of
the invention is not limited as just described. For example,
abrasive particle rows can have bigger abrasive particles and
smaller abrasive particles alternately arranged.
[0069] Also, according to the invention, abrasive particle rows can
be formed in such a manner that bigger abrasive particles are
successively arranged and then smaller abrasive particles are
arranged, or bigger abrasive particles are arranged and then small
abrasive particles are successively arranged.
[0070] Although as in FIG. 3 to 5, two types of abrasive particles
of bigger abrasive particles and smaller abrasive particles can be
used, the conditioner of the invention is not limited thereto.
Also, as shown in FIG. 6 to 8, the conditioner can be manufactured
in such a manner that mid-sized abrasive particles are added to the
bigger and smaller abrasive particles. Alternatively, much smaller
particles, sized smaller than the smaller abrasive particles may be
added to the arrangement. This results in improved conditioning
effects.
[0071] As shown in FIG. 6, the invention uses bigger abrasive
particles 63a, smaller abrasive particles 63b and mid-sized
abrasive particles 63c as abrasive particles 63, and a row of
abrasive particles 631 is formed by each abrasive particle. A
conditioner 60 can be manufactured by alternately arranging the
rows of abrasive particles 631a, 631b and 631c to form a pattern
64.
[0072] As shown in FIG. 7, the invention uses bigger abrasive
particles 73a, smaller abrasive particles 73b and mid-sized
abrasive particles 73c as abrasive particles 73, and a row of
abrasive particles 731 is formed by each abrasive particle. The
rows of abrasive particles 731a, 731b and, 731c form patterns 74a,
74b and 74c and a conditioner 70 is manufactured by alternately
arranging the patterns.
[0073] Further, as shown in FIG. 8, the invention uses bigger
abrasive particles 83a, smaller abrasive particles 83b and
mid-sized abrasive particles 83c as abrasive particles 83, and a
row of abrasive particles is formed by alternately arranging each
abrasive particle. A conditioner 80 is manufactured in such a
manner that the rows of abrasive particles are arranged to form a
pattern 84.
[0074] Also, according to the invention, a row of abrasive
particles can be formed by arranging at least two particles of any
size, and then arranging other abrasive particles in succession by
one or two. Alternatively, at least two abrasive particles of one
size may be arranged in succession, and alternate with other sized
abrasive particles, which are also arranged in succession by
two.
[0075] In this case, a gap between abrasive particle rows having at
least one of biggest abrasive particle is preferably 2.5 to 150
times the average diameter of the biggest abrasive particles, and
more preferably, 2.5 to 100 times the average diameter of the
bigger abrasive particles. Thereby superior dressing effects can be
attained.
[0076] FIG. 9 illustrates an example of the conditioner in which a
number of pellets having abrasive particles attached thereto by a
layer of metal binder are bonded to a metal substrate according to
the invention. FIG. 9(a) shows a sectional view of the conditioner
and FIG. 9(b) shows a schematic view of the conditioner.
[0077] Unlike a conditioner having abrasive particles attached to a
metal substrate by a layer of metal binder, the present invention,
as shown in FIG. 9, allows a conditioner 100 including a number of
pellets 105 having abrasive particles 102 attached to a metal
substrate 101 by a layer of metal binder 103 to control arrangement
of the pellets. This leads to better dressing effects.
[0078] In this case, abrasive particles can be arranged in the
pellet in any of the aforesaid arrangement.
[0079] For example, as in FIG. 3, two types of abrasive particles
with size difference are alternately attached in the pellet. Also,
as in FIG. 4, abrasive particles with the same size are attached in
the pellet so that each pellet has different sizes.
[0080] In addition, abrasive particles with different size can be
arranged circlewise in the pellets which are arranged as shown in
FIG. 5, or numerous other abrasive particles with different sizes
are applicable to pellets according to the method for arranging
abrasive particles of the invention.
[0081] The pellets can be equally sized or differently sized, or a
shape of the pellets can be modified.
[0082] A technical object of the invention is not only applied to a
conditioner for CMP pad but to a cutting tool.
[0083] The invention will be explained in greater detail in the
examples which follow.
EXAMPLE 1
[0084] The products prepared include a conditioner of random
arrangement having abrasive particles without size difference
randomly arranged (conventional product 1), a conditioner of
conventional patterning having abrasive particles without size
difference regularly arranged (conventional product 2), a
conditioner of the invention having at least 2 abrasive particles
with size difference alternately attached in a row to a segment
(inventive product 1), a conditioner of the invention having at
least 2 abrasive particles with size difference alternately
attached to each segment (inventive product 2), and a conditioner
of the invention having abrasive particles attached in a row
forming a circle (inventive product 3).
[0085] With respect to the conventional conditioner and the
conditioner of the invention, an evaluation was conducted on cut
rate of pad and fracture of abrasive particles. The results are
shown in Table 1. TABLE-US-00001 TABLE 1 Evaluation results
Fracture or pulling out Pad cut rate(.mu.m/hr) of abrasive 1.sup.st
2.sup.nd 3.sup.rd Variation particles Conventional product 1 322
357 298 59 None Conventional product 2 403 378 417 39 None
Inventive product 1 466 460 472 12 None Inventive product 2 455 442
439 16 None Inventive product 3 433 421 420 13 None
[0086] As shown in Table 1, conventional product 1 has low cut rate
of pad, with big variations in pad cut rate for each conditioner.
Conventional product 2 indicates improvement in cut rate of pad
amount from conventional product 1 but varies to some extent in
terms of reproducibility of products.
[0087] Meanwhile, inventive products 1, 2 and 3 show a great
excellence in wear amount and reproducibility of products compared
with the conventional conditioner.
[0088] Generally, a high abrasion effect increases stress of
abrasion particles involved in dressing, possibly causing fracture
or pulling out thereof. Invention products 1, 2 and 3 did not
suffer fracture or pulling out of abrasive particles.
EXAMPLE 2
[0089] The products prepared include a conditioner (comparative
product 1) representing less than 10% size difference between
bigger and smaller abrasive particles, a conditioner (inventive
product 4) having abrasive particles with 10 to 40% of size
difference and a conditioner (comparative product 2) having
abrasive particles with 45 to 70% of size difference. The products
have bigger and smaller abrasive particles in a row at a
predetermined rate.
[0090] For the conditioners manufactured as just described, wafer
removal rate was measured on a time basis and the results are shown
in table 2 below. TABLE-US-00002 TABLE 2 Wafer removal rate
(.ANG./min) 1 20 40 hour hours hours Average variation Comparative
product 1 3642 3287 2769 3233 873 Inventive product 4 3685 3514
3397 3532 288 Comparative product 2 3991 3102 2554 3215 1437
[0091] As shown in Table 2, for comparative product 1 having
abrasive particles with less than 10% size difference, wafer
removal rate after 40-hour use drops significantly from the initial
removal rate.
[0092] That is because abrasive particles are gradually worn away
during dressing but due to little height variation in abrasive
particles, abrasive particles with new sharp edges are not created,
consequently unable to perform effective pad dressing so that wafer
removal rate diminishes.
[0093] Since comparative product 1 has a greater number of
abrasives particles playing a substantial role in abrasion process
than comparative product 2, comparative product 1 shows higher
removal rate and less reduction in removal rate.
[0094] For inventive product 4 having abrasive particles with 10 to
40% size difference, overall removal rate is high and variation of
wafer removal rate on a time basis is not considerable. This means
good conditioning effects and uniform removal rate.
[0095] For comparative product 2 having abrasive particles with 45
to 70% of size difference, bigger abrasive particles used for
abrasion process sustain more load than those of comparative
product 1 and inventive product 4 and thus deeply penetrate the pad
so that removal rate is high in the early stage.
[0096] With abrasive particles worn away, new abrasive particles or
smaller abrasive particles should engage in dressing, but cannot
due to wide size difference, leading to sharp decrease in removal
rate.
EXAMPLE 3
[0097] Manufactured were conditioners having bigger abrasive
particles, mid-sized abrasive particles and smaller abrasive
particles with 10-40% of overall size difference arranged in a row.
With respect to the conditioners, an evaluation was conducted on
cut rate of pad and the results are shown in Table 3 below.
[0098] In Table 3 below, inventive product 5 is a conditioner
having bigger abrasive particles A, mid-sized abrasive particles B
and smaller abrasive particles C arranged successively in a row.
Inventive product 6 is a conditioner having bigger abrasive
particles A, smaller abrasive particles C and mid-sized abrasive
particles B arranged successively in a row. Conventional product 1
is a conditioner having abrasive particles without size difference
arranged randomly. TABLE-US-00003 TABLE 3 Pad cut rate (.mu.m/hr)
1st 2nd 3rd Average variation Inventive product 5 457 449 461 456
12 Inventive product 6 455 457 440 451 17 Conventional product 1
322 357 298 325 59
[0099] As shown in table 3, if abrasive particles have 10 to 40% of
size difference and are arranged in a row, inventive product 5 and
6 indicate little difference in cut rate of pad although bigger
abrasive particles, mid-sized particles and smaller particles are
arranged in a different order. Also they indicate higher cut rate
and more uniform cut rate than conventional conditioner 1.
EXAMPLE 4
[0100] An evaluation was conducted on variations in cut rate of pad
when a gap of bigger abrasive particles arranged in a row was large
or small. The results are shown in Table 4.
[0101] With respect to conditioners of inventive product used in
this example, abrasive particles with size difference of 10 to 40%
were used and arranged in a row.
[0102] Inventive product 7 in Table 4 shows a conditioner in which
a gap between bigger abrasive particles arranged in a row and
bigger abrasive particles arranged in the next row is 2.5 times the
diameter of the bigger abrasive particles; in invention product 8,
the gap is 25 times, in inventive product 9, the gap is 50 times,
in inventive product 10, the gap is 100 times, in inventive product
11, the gap is 150 times, and in inventive product 12, the gap is
200 times. TABLE-US-00004 TABLE 4 Pad cut rate [.mu.m/hr] 1.sup.st
2nd 3rd Average Conventional product 1 322 357 298 326 Inventive
product 7 400 424 407 410 Inventive product 8 459 470 474 468
Inventive product 9 467 459 446 457 Inventive product 10 448 434
461 448 Inventive product 11 383 400 395 393 Inventive product 12
352 329 342 341
[0103] As shown in Table 4, conditioners of invention product
having 10-40% size difference and arranged in a row indicate
excellent pad cut rate and narrow variance thereof.
[0104] When a gap of rows of bigger abrasives playing a significant
role in dressing is 2.5 to 100 times the diameter of the bigger
abrasive particles, cut rate of pad is greatly increased. When the
gap is 150 times, cut rate of pad is higher than that of
conventional product 1.
[0105] However, when the gap of rows of bigger abrasive particles
is more than 150 times the diameter of the bigger abrasive
particles, cut rate of pad is less increased than that of
conventional product 1.
[0106] Consequently, if the gap of rows of bigger abrasives is less
than 2.5 times the diameter of the bigger abrasive particles, the
bigger abrasive particles cannot deeply penetrate a pad, reducing
dressing efficiency. If the gap is greater than 150 times, due to a
small number of bigger abrasive particles, cut rate of pad
increases in the early stage but with time passing, abrasive
particles are quickly worn away, leading to less improvement in cut
rate of pad.
[0107] As stated above, the present invention provides a
conditioner having at least 2 abrasive particles with size
difference arranged uniformly and abrasive particles with size
difference attached in a desired ratio and position. Thereby, the
cutting tool will experience improvement in useful life and
dressing effects, and realize superior reproducibility of
performance.
[0108] While the present invention has been shown and described in
connection with the preferred embodiments, it will be apparent to
those skilled in the art that modifications and variations can be
made without departing from the spirit and scope of the invention
as defined by the appended claims.
* * * * *