U.S. patent application number 12/213423 was filed with the patent office on 2009-03-12 for slurry, chemical mechanical polishing method using the slurry, and method of forming metal wiring using the slurry.
Invention is credited to Chang-Ki Hong, Sung-Jun Kim, Jae-Dong Lee, Jeong-Heon Park.
Application Number | 20090068839 12/213423 |
Document ID | / |
Family ID | 36076482 |
Filed Date | 2009-03-12 |
United States Patent
Application |
20090068839 |
Kind Code |
A1 |
Kim; Sung-Jun ; et
al. |
March 12, 2009 |
Slurry, chemical mechanical polishing method using the slurry, and
method of forming metal wiring using the slurry
Abstract
A slurry, chemical mechanical polishing (CMP) method using the
slurry, and method of forming metal wiring using the slurry. The
slurry may include a polishing agent, an oxidant, and at least one
defect inhibitor to protect the metal film. The CMP method and
method of forming metal wiring may employ one or two slurries with
at least one of the slurries including at least one defect
inhibitor.
Inventors: |
Kim; Sung-Jun; (Suwon-si,
KR) ; Park; Jeong-Heon; (Suwon-si, KR) ; Hong;
Chang-Ki; (Seongnam-si, KR) ; Lee; Jae-Dong;
(Suwon-si, KR) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 8910
RESTON
VA
20195
US
|
Family ID: |
36076482 |
Appl. No.: |
12/213423 |
Filed: |
June 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11077150 |
Mar 11, 2005 |
7442646 |
|
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12213423 |
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Current U.S.
Class: |
438/692 ;
257/E21.23 |
Current CPC
Class: |
C09G 1/02 20130101; H01L
21/3212 20130101 |
Class at
Publication: |
438/692 ;
257/E21.23 |
International
Class: |
H01L 21/306 20060101
H01L021/306 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2004 |
KR |
2004-0061226 |
Claims
1.-21. (canceled)
22. A chemical mechanical polishing (CMP) method for a metal film
formed on a semiconductor substrate, the method comprising:
preparing a slurry including a polishing agent, an oxidant, and at
least one defect inhibitor to protect the metal film; and
performing chemical mechanical polishing (CMP) of the metal film
using the slurry.
23. The method of claim 22, wherein a removal rate selectivity of
the slurry is 20-1:1.
24. The method of claim 23, wherein the removal rate selectivity of
the slurry is 17-1.5:1.
25. The method of claim 22, wherein a first of the at least one
defect inhibitors forms a protective layer on the metal film.
26. The method of claim 22, wherein the first of the at least one
defect inhibitors adsorbs onto a surface of the metal film.
27. The method of claim 22, wherein the first of the at least one
defect inhibitors includes a polymeric compound further including a
carboxyl group.
28. The method of claim 27, wherein the first of the at least one
defect inhibitors includes a co-polymer further including acrylic
acid.
29. The method of claim 28, wherein a content of the first of the
at least one defect inhibitors is in a range of 0.01-20 weight %
(inclusive) of a total weight of the slurry.
30. The method of claim 27, wherein the first of the at least one
defect inhibitors includes at least one material selected from the
group consisting of PAA, PAMA, salts thereof, and mixtures
thereof.
31. The method of claim 30, further comprising a chelating
agent.
32. The method of claim 31, wherein a content of the chelating
agent is in a range of 0.01-20 weight % (inclusive) of a total
weight of the slurry.
33. The method of claim 31, wherein the chelating agent includes at
least one material selected from the group consisting of EDTA, NTA,
DTPA, HEDTA, MGDA, salts thereof, and mixtures thereof.
34. The method of claim 22, wherein a content of the polishing
agent is in a range of 0.5-20 weight % (inclusive) of a total
weight of the slurry.
35. The method of claim 34, wherein the polishing agent includes at
least one material selected from the group consisting of colloidal
silica and fumed silica.
36. The method of claim 22, wherein a content of the oxidant is in
a range of 0.5-5 weight % (inclusive) of a total weight of the
slurry.
37. The method of claim 36, wherein the oxidant includes at least
one material selected from the group consisting of hydrogen
peroxide and ammonium persulfate.
38. The method of claim 30, further comprising a pH controller for
controlling a pH of the slurry.
39. The method of claim 38, wherein the pH controller includes at
least one material selected from the group consisting of
H.sub.3PO.sub.4, HNO.sub.3, and H.sub.2SO.sub.4.
40. The method of claim 38, wherein the pH controller lowers the pH
of the slurry and raises a zeta potential of the metal film between
the metal film and the slurry.
41. The method of claim 30, wherein the first of the at least one
defect inhibitors further lowers a pH of the slurry.
42. The method of claim 41, wherein the first of the at least one
defect inhibitors further includes H+ ions.
43. The method of claim 22, wherein the metal film is an aluminum
or aluminum alloy film.
44. The method of claim 22, wherein the metal film forms a wiring
or a plug.
45. A chemical mechanical polishing (CMP) method for a metal film
formed on a semiconductor substrate, the method comprising:
preparing a first slurry including a polishing agent and an
oxidant; performing chemical mechanical polishing (CMP) of the
metal film using the first slurry; preparing a second slurry
including a polishing agent, an oxidant, and at least one defect
inhibitor to protect the metal film; and performing chemical
mechanical polishing (CMP) of the metal film using the second
slurry.
46. The method of claim 45, wherein a removal rate selectivity of
the first slurry is greater than removal rate selectivity of the
second slurry.
47. The method of claim 46, wherein the removal rate selectivity of
the first slurry is >50:1 and the removal rate selectivity of
the second slurry is 20-1:1.
48. The method of claim 47, wherein the removal rate selectivity of
the second slurry is 17-1.5:1.
49. The method of claim 45, wherein a first of the at least one
defect inhibitors forms a protective layer on the metal film.
50. The method of claim 45, wherein the first of the at least one
defect inhibitors adsorbs onto a surface of the metal film.
51. The method of claim 45, wherein the first of the at least one
defect inhibitors includes a polymeric compound further including a
carboxyl group.
52. The method of claim 51, wherein the first of the at least one
defect inhibitors includes a co-polymer further including acrylic
acid.
53. The method of claim 52, wherein a content of the first of the
at least one defect inhibitors is in a range of 0.01-20 weight %
(inclusive) of a total weight of the slurry.
54. The method of claim 51, wherein the first of the at least one
defect inhibitors includes at least one material selected from the
group consisting of PAA, PAMA, salts thereof, and mixtures
thereof.
55. The method of claim 54, further comprising a chelating
agent.
56. The method of claim 55, wherein a content of the chelating
agent is in a range of 0.01-20 weight % (inclusive) of a total
weight of the slurry.
57. The method of claim 55, wherein the chelating agent includes at
least one material selected from the group consisting of EDTA, NTA,
DTPA, HEDTA, MGDA, salts thereof, and mixtures thereof.
58. The method of claim 45, wherein a content of the polishing
agent is in a range of 0.5-20 weight % (inclusive) of a total
weight of the slurry.
59. The method of claim 58, wherein the polishing agent includes at
least one material selected from the group consisting of colloidal
silica and fumed silica.
60. The method of claim 45, wherein a content of the oxidant is in
a range of 0.5-5 weight % (inclusive) of a total weight of the
slurry.
61. The method of claim 60, wherein the oxidant includes at least
one material selected from the group consisting of hydrogen
peroxide and ammonium persulfate.
62. The method of claim 54, further comprising a pH controller for
controlling a pH of the slurry.
63. The method of claim 62, wherein the pH controller includes at
least one material selected from the group consisting of
H.sub.3PO.sub.4, HNO.sub.3, and H.sub.2SO.sub.4.
64. The method of claim 62, wherein the pH controller lowers the pH
of the slurry and raises a zeta potential of the metal film between
the metal film and the slurry.
65. The method of claim 54, wherein the first of the at least one
defect inhibitors further lowers a pH of the slurry.
66. The method of claim 65, wherein the first of the at least one
defect inhibitors further includes H+ ions.
67. The method of claim 45, wherein the metal film is an aluminum
or aluminum alloy film.
68. The method of claim 45, wherein the metal film forms a wiring
or a plug.
Description
PRIORITY STATEMENT
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(a) of Korean Patent Application No. 2004-0061226 filed on Aug.
3, 2004, the contents of which are hereby incorporated by reference
in their entirety.
BACKGROUND OF THE INVENTION
[0002] Aluminum which includes aluminum alloys is one of the
conductive materials used for forming wiring or a plug for
semiconductor devices. An aluminum alloy may be defined as any
composition where aluminum is the main component.
[0003] Conventionally, an aluminum film may be deposited using a
sputtering method or a CVD method, and an aluminum pattern may be
formed by etching the aluminum film using a reactive ion etch (RIE)
method. Drawbacks of the conventional RIE method may include bridge
problems and/or voids in the aluminum wiring patterns due to heat
stress.
[0004] Recently, a damascene process has been widely used for
forming aluminum wiring. A conventional damascene process is a
process in which interconnect metal lines may be delineated in
dielectrics isolating the interconnect metal lines from each other
by chemical mechanical planarization or chemical mechanical
polishing (CMP). In a conventional damascene process, an
interconnect pattern may be lithographically defined in a layer of
dielectric, metal is deposited to fill resulting trenches, and
excess metal is removed by CMP. A conventional damascene process
for forming metal wiring, such as aluminum wiring or copper wiring,
is shown in FIGS. 1-5.
[0005] As shown in FIG. 1, a conventional damascene process may
include depositing an inter metal dielectric layer (IMD) 12 on a
substrate 10 and defining a region 14 for forming a metal wiring by
patterning the IMD 12, as shown in FIG. 2.
[0006] As shown in FIG. 3, a conventional damascene process may
further include forming a barrier metal layer 16, depositing a
thick aluminum film 18 on the barrier metal layer 16, as shown in
FIG. 4, and removing the aluminum film 18 and the barrier metal
layer 16 on an upper surface of the IMD 12 using a CMP process, as
shown in FIG. 5.
[0007] In the conventional damascene process for forming aluminum
wiring as described above, the CMP process may affect one or more
electrical characteristics of the aluminum wiring. More
particularly, a removal rate selectivity of the CMP slurry may be a
factor that may affect an electrical characteristic of the aluminum
wiring.
[0008] When the removal rate selectivity of an aluminum film to a
silicon oxide film, such as the aluminium film 16 to the Inter
Metal Dielectric (IMD) layer 12 of FIGS. 1-5, is low, the aluminum
film 16 can be overetched during the CMP process. Overetching may
result in a damascene of a surface area of the aluminum wiring,
which may increase an electrical resistance of the aluminum wiring.
Accordingly, the speed of a signal transferred via the aluminum
wiring of a semiconductor device may become slower, and eventually
overall performance of the semiconductor device may be
degraded.
[0009] As set forth above, low removal rate selectivity of a metal
film, such as an aluminum film to a silicon oxide film may cause
overetching of the aluminum film, decrease a surface area of the
aluminum wiring, increase an electrical resistance of the aluminum
wiring, reduce the speed a signal transferred via the aluminum
wiring of a semiconductor device, and/or degrade the an overall
performance of the semiconductor device.
[0010] Conversely, a high removal rate selectivity of metal film to
silicon oxide film may cause defects such as scratches, corrosion,
and/or pitting. A scratch defect, shown in FIG. 6, is a surface
roughness which may result from damage caused by a polishing agent
on a surface of the aluminum film. A pitting defect, shown in FIG.
7, on the surface of the aluminum film can occur when a scratch
defect is more severe. A corrosion defect, shown in FIG. 8, may
occur when aluminum ions break away from the aluminum film due to a
chemical reaction with other materials.
[0011] The above-described defects may be caused by the soft
characteristics of the metal, for example, aluminium, which has a
relatively low hardness and resistance to stress. Scratches,
corrosions, or pits on an aluminum film may not only reduce a
reflective index of the metal, but may also decrease a reliability
of the metal wiring, which in a worst case may lead to a
disconnection in the metal wiring.
SUMMARY OF THE INVENTION
[0012] Example embodiments of the present invention are directed to
a slurry for a chemical mechanical polishing (CMP) method for
polishing a metal film, such as an aluminum film, which provides a
high removal rate selectivity of metal film to another film, such
as a silicon oxide film, a CMP method using the slurry, and a
method of forming an aluminum wiring using the CMP method.
[0013] Example embodiments of the present invention are directed to
a CMP slurry for an aluminum film, which can reduce or prevent
scratches, pitting, corrosion, and/or defects on a surface of a
metal film, such as an aluminium film, a CMP method using the
slurry, and a method of forming an aluminum wiring using the CMP
method.
[0014] Example embodiments of the present invention are directed to
a CMP slurry for an aluminum film, which can reduce or prevent
dishing and/or erosion defects on a surface of a metal film, such
as an aluminium film, a CMP method using the slurry, and a method
of forming an aluminum wiring using the CMP method.
[0015] Example embodiments of the present invention are directed to
a high removal rate selectivity of a metal film, such as an
aluminium film, to another film, such as silicon oxide film,
reducing or preventing a surface of the metal layer from scratches,
pits, and/or corrosion defects and/or reducing or preventing a
surface of the metal layer from dishing and/or erosion defects.
[0016] Example embodiments of the present invention are directed to
slurries, chemical mechanical polishing (CMP) methods using the
slurries, and method of forming metal wiring using the slurries. In
an example embodiment, the slurry may include a polishing agent, an
oxidant, and at least one defect inhibitor to protect the metal
film. In an example embodiment, the CMP methods and method of
forming metal wiring may employ one or two slurries with at least
one of the slurries including at least one defect inhibitor.
[0017] In an example embodiment, the present invention is directed
to a slurry may include a polishing agent, an oxidant, and at least
one defect inhibitor to protect the metal film.
[0018] In an example embodiment, the present invention is directed
to a chemical mechanical polishing (CMP) method for a metal film
formed on a semiconductor substrate, the method including preparing
a slurry including a polishing agent, an oxidant, and at least one
defect inhibitor to protect the metal film, and performing chemical
mechanical polishing (CMP) of the metal film using the slurry.
[0019] In an example embodiment, the present invention is directed
to a chemical mechanical polishing (CMP) method for a metal film
formed on a semiconductor substrate, the method including preparing
a first slurry including a polishing agent and an oxidant,
performing chemical mechanical polishing (CMP) of the metal film
using the first slurry, preparing a second slurry including a
polishing agent, an oxidant, and at least one defect inhibitor to
protect the metal film, and performing chemical mechanical
polishing (CMP) of the metal film using the second slurry.
[0020] In an example embodiment, the present invention is directed
to a method for forming a metal wiring including forming an inter
metal dielectric layer on a semiconductor substrate, patterning the
inter metal dielectric layer to define a region for the wiring,
forming a barrier metal layer on the patterned inter metal
dielectric layer, forming a metal film by depositing a metal on the
barrier metal layer, and polishing the metal film using a slurry
including a polishing agent, an oxidant, and at least one defect
inhibitor to protect the metal film to form the metal wiring.
[0021] In an example embodiment, the present invention is directed
to a method for forming a metal wiring including forming an inter
metal dielectric layer on a semiconductor substrate, patterning the
inter metal dielectric layer to define a region for the wiring,
forming a barrier metal layer on the patterned inter metal
dielectric layer, forming a metal film by depositing a metal on the
barrier metal layer, polishing the metal film using a first slurry
including a polishing agent and an oxidant, and polishing the metal
film using a second slurry including a polishing agent, an oxidant,
and at least one defect inhibitor to protect the metal film to form
the metal wiring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The present invention will become more fully understood from
the detailed description given below and the accompanying drawings,
which are given for purposes of illustration only, and thus do not
limit the invention.
[0023] FIGS. 1-5 illustrate a conventional damascene process.
[0024] FIG. 6 illustrates scratches on an aluminum film polished by
a conventional slurry with a high removal rate selectivity of
aluminum film to silicon oxide.
[0025] FIG. 7 illustrates pitting on an aluminum film polished by a
conventional slurry with a high removal rate selectivity of
aluminum film to silicon oxide.
[0026] FIG. 8 illustrates corrosion on an aluminum film polished by
a conventional slurry with a high removal rate selectivity of
aluminum film to silicon oxide.
[0027] FIG. 9 illustrates the zeta potential of an example,
negatively charged particle.
[0028] FIG. 10 illustrates zeta potential as a function of pH for
an aluminium wafer, a silicon wafer, and a tetraethyl orthosilicate
(TEOS) wafer.
[0029] FIG. 11 illustrates the dissociation of a polymeric compound
may in into anions to form a passivation layer by adsorbing onto
the surface of the metal layer and cations to acidify a CMP slurry
solution.
[0030] FIGS. 12A and 12B illustrate an aluminum surface of a first
device after CMP using a conventional slurry and a slurry in
accordance with an example embodiment of the present invention,
respectively.
[0031] FIGS. 13A and 13B illustrate an aluminum surface of a first
device after CMP using a conventional slurry and a slurry in
accordance with an example embodiment of the present invention,
respectively.
[0032] FIGS. 14-16 illustrate the formation of a metal film using
one conventional slurry and two slurries in accordance with example
embodiments of the present invention, respectively.
[0033] FIG. 17 illustrates an example method of performing CMP in
accordance with the present invention using a slurry including an
abrasive, an oxidizer, and at least one defect inhibitor.
[0034] FIG. 18 illustrates another example method of performing CMP
in accordance with the present invention using a first slurry
including an abrasive and an oxidizer and a second slurry including
an abrasive, an oxidizer, and at least one defect inhibitor.
[0035] FIGS. 19-21 illustrate the formation of a metal film, such
as an aluminum film by polishing with two CMP slurries in
accordance with example embodiments of the present invention
[0036] FIG. 22 illustrates an -example method of forming metal
wiring in accordance with the present invention using a slurry
including an abrasive, an oxidizer, and at least one defect
inhibitor.
[0037] FIG. 23 illustrates another example method of forming metal
wiring in accordance with the present invention using a first
slurry including an abrasive and an oxidizer and a second slurry
including an abrasive, an oxidizer, and at least one defect
inhibitor.
[0038] It should be noted that these Figures are intended to
illustrate the general characteristics of methods and devices of
example embodiments of this invention, for the purpose of the
description of such example embodiments herein. These drawings are
not, however, to scale and may not precisely reflect the
characteristics of any given embodiment, and should not be
interpreted as defining or limiting the range of values or
properties of example embodiments within the scope of this
invention.
[0039] In particular, the relative thicknesses and positioning of
layers or regions may be reduced or exaggerated for clarity.
Further, a layer is considered as being formed "on" another layer
or a substrate when formed either directly on the referenced layer
or the substrate or formed on other layers or patterns overlaying
the referenced layer.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE PRESENT
INVENTION
[0040] Example embodiments of the present invention provide a
slurry composition for use in a CMP process and/or a method of
forming metal wiring, having a high removal rate selectivity, the
slurry composition including a compound providing a protective
layer-forming function to a metal layer, such as an aluminum layer,
by adsorbing onto the surface of the metal layer, thereby reducing
or preventing the formation of defects on the surface of the metal,
such as scratches, pits, corrosion, dishing and/or erosion.
[0041] The compound may provide the protective layer-forming
function to the metal layer by generating anions with a negative
charge (-) that adsorb onto the surface of the metal layer having
cations with a positive (+) charge to form a protective layer. The
compound may also generate cations, for example H.sup.+ ions, that
increase the acidity the CMP slurry solution.
[0042] The adsorbility of the compound to the metal layer in a CMP
slurry solution may increase as pH decreases because the zeta
potential between the metal layer and the CMP slurry solution
increases as the pH decreases.
[0043] FIG. 9 illustrates the zeta potential of an example,
negatively charged particle. The negatively charged particle has a
surface with a negative charge. In the solution (for example,
water) near the particle, is a first layer of mostly positive ions
and then a second layer of mostly negative ions. The first and
second layers are immobile ions. As the distance from the particle
increases further, the mixture of positive and negative ions
approaches the mixture of positive and negative ions in the bulk
fluid. As shown in FIG. 9, the outer circle is about where the
mixture of positive and negative ions is equally distributed.
[0044] Movement of the ions in the two shells at the surface of the
particle (the Helmholtz double layer) is greatly restricted. They
accompany the particle and dissipate some of its charge. After
these two shells, there exists a "slip plane". The zeta potential
is the difference in charge between the bulk fluid and the particle
with its held, attracted ions. Zeta potential is dependent upon the
ionic concentration, pH, viscosity, and dielectric constant of the
solution being analyzed.
[0045] FIG. 10 illustrates zeta potential as a function of pH for
an aluminium wafer, a silicon wafer, and a tetraethyl orthosilicate
(TEOS) wafer.
[0046] Polymeric compounds having a carboxyl group are suitable
compounds that can generate anions which adsorb onto the surface of
a metal layer and hydrogen ions, which acidify the CMP slurry
solution. As shown in FIG. 11, a polymeric compound may dissociate
in the CMP slurry solution into carboxylate anions (COO.sup.-) to
form a passivation layer by adsorbing onto the surface of the
aluminum layer 18 and hydrogen ions (H.sup.+) to acidify the CMP
slurry solution.
[0047] In an example embodiment, the slurry includes an abrasive,
an oxidizer, a pH controller, and/or one or more defect inhibitors.
In an example embodiment, the abrasive may be a silica, such as
colloidal silica and/or fumed silica, from 0.5 to 20 weight %
(inclusive).
[0048] In an example embodiment, the oxidizer may be hydrogen
peroxide (H.sub.2O.sub.2) and/or ammonium persulfate
(NH4).sub.2S.sub.2O.sub.8, from 0.5 to 5 weight % (inclusive).
[0049] In an example embodiment, the pH controller is one or more
of H.sub.3PO.sub.4, HNO.sub.3, and H.sub.2SO.sub.4. In an example
embodiment, the pH is in the acid region because the zeta potential
is positive in the acid region. In an example embodiment, the pH is
less than 7. In an example embodiment, the pH is 2-4
(inclusive).
[0050] In an example embodiment, one of the defect inhibitors may
be a polymeric compound having carboxyl group. Examples include
poly acrylic acid (PAA), poly acrylic acid co maleic acid (PAMA),
salts thereof, and mixtures thereof. In an example embodiment,
another of the defect inhibitors may include a chelating agent,
from 0.01 to 20 weight % (inclusive). Examples include ethylene
diaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA),
diethylenetriaminepentaacetic acid (DTPA), hydroxyethyl ethylene
diaminetriacetic acid (HEDTA), methylglycinediacetic acid (MGDA),
salts thereof, and mixtures thereof.
[0051] In an example embodiment, one of the defect inhibitors may
form a protective layer on the metal film. In an example
embodiment, one of the defect inhibitors may adsorb onto a surface
of the metal film. In an example embodiment, one of the defect
inhibitors may include a polymeric compound further including a
carboxyl group. In an example embodiment, one of the defect
inhibitors may include a co-polymer further including acrylic
acid.
[0052] In an example embodiment, a content of one of the defect
inhibitors may be in a range of 0.01-20 weight % (inclusive) of a
total weight of the slurry. In an example embodiment, a content of
one of the defect inhibitors may be in a range of 0.01-10 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of one of the defect inhibitors may be in a
range of 10-20 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of one of the defect
inhibitors may be in a range of 0.01-5 weight % (inclusive) of a
total weight of the slurry. In an example embodiment, a content of
one of the defect inhibitors may be in a range of 5-10 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of one of the defect inhibitors may be in a
range of 10-15 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of one of the defect
inhibitors may be in a range of 15-20 weight % (inclusive) of a
total weight of the slurry. In an example embodiment, a content of
one of the defect inhibitors may be in a range of 0.01-3 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of one of the defect inhibitors may be in a
range of 0.01-1 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of one of the defect
inhibitors may be in a range of 0.01-0.5 weight % (inclusive) of a
total weight of the slurry. In an example embodiment, a content of
one of the defect inhibitors may be in a range of 0.01-0.1 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of one of the defect inhibitors may be in a
range of 0.01-0.05 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of one of the defect
inhibitors may be in a range of 0.1-0.5 weight % (inclusive) of a
total weight of the slurry. In an example embodiment, a content of
one of the defect inhibitors may be in a range of 0.2-0.3 weight %
(inclusive) of a total weight of the slurry.
[0053] In an example embodiment, one of the defect inhibitors may
include at least one material selected from the group consisting of
PAA, PAMA, salts thereof, and mixtures thereof. In an example
embodiment, one of the defect inhibitors may include a PM salt or a
PAMA salt. In an example embodiment, one of the defect inhibitors
may include PM or PAMA. In an example embodiment, one of the defect
inhibitors may lower a pH of the slurry. In an example embodiment,
one of the defect inhibitors may include H.sup.+ ions. In an
example embodiment, one of the defect inhibitors reduces at least
one of scratching, corrosion, pitting, dishing, and/or erosion.
[0054] In an example embodiment, another of the defect inhibitors
may be a chelating agent. In an example embodiment, a content of
the chelating agent may be in a range of 0.01-20 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of the chelating agent may be in a range of
0.01-10 weight % (inclusive) of a total weight of the slurry. In an
example embodiment, a content of the chelating agent may be in a
range of 10-20 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of the chelating agent
may be in a range of 0.01-5 weight % (inclusive) of a total weight
of the slurry. In an example embodiment, a content of the chelating
agent may be in a range of 5-10 weight % (inclusive) of a total
weight of the slurry. In an example embodiment, a content of the
chelating agent may be in a range of 10-15 weight % (inclusive) of
a total weight of the slurry. In an example embodiment, a content
of the chelating agent may be in a range of 15-20 weight %
(inclusive) of a total weight of the slurry. In an example
embodiment, a content of the chelating agent may be in a range of
0.01-3 weight % (inclusive) of a total weight of the slurry. In an
example embodiment, a content of the chelating agent may be in a
range of 0.01-1 weight % (inclusive) of a total weight of the
slurry. In an example embodiment, a content of the chelating agent
may be in a range of 0.01-0.5 weight % (inclusive) of a total
weight of the slurry. In an example embodiment, a content of the
chelating agent may be in a range of 0.01-0.3 weight % (inclusive)
of a total weight of the slurry. In an example embodiment, a
content of the chelating agent may be in a range of 0.01-0.2 weight
% (inclusive) of a total weight of the slurry. In an example
embodiment, a content of the chelating agent may be in a range of
0.05-0.15 weight % (inclusive) of a total weight of the slurry. In
an example embodiment, a content of the chelating agent may be in a
range of 0.2-0.3 weight % (inclusive) of a total weight of the
slurry.
[0055] In an example embodiment, the chelating agent may include at
least one material selected from the group consisting of EDTA, NTA,
DTPA, HEDTA, MGDA, salts thereof, and mixtures thereof. In an
example embodiment, another of the defect inhibitors reduces at
least one of scratching, corrosion, pitting, dishing, and/or
erosion.
[0056] In an example embodiment, a content of the abrasive (or
polishing agent) may be in a range of 0.5-20 weight % (inclusive)
of a total weight of the slurry. In an example embodiment, the
abrasive (or polishing agent) may include at least one material
selected from the group consisting of colloidal silica and fumed
silica.
[0057] In an example embodiment, a content of the oxidizer (or
oxidant) may be in a range of 0.5-5 weight % (inclusive) of a total
weight of the slurry. In an example embodiment, the oxidizer (or
oxidant) may include at least one material selected from the group
consisting of hydrogen peroxide and ammonium persulfate.
[0058] In an example embodiment, the pH controller controls a pH of
the slurry. In an example embodiment, the pH controller may include
at least one material selected from the group consisting of
H.sub.3PO.sub.4, HNO.sub.3, and H.sub.2SO.sub.4. In an example
embodiment, the pH controller lowers the pH of the slurry and
raises a zeta potential of the metal film between the metal film
and the slurry.
[0059] In an example embodiment, the metal film is an aluminum or
aluminum alloy film or a copper or copper alloy film. In an example
embodiment, the metal film may be used to form a wiring or a
plug.
[0060] To test the effect of the defect inhibitor having a carboxyl
group, a slurry in accordance with an example embodiment of the
present invention including 10 weight % colloidal silica, 1 weight
% hydrogen peroxide, 0.1 weight % EDTA and 0.25 weight % PAMA (a
defect inhibitor including the carboxyl group) and a conventional
CMP slurry including 10 weight % colloidal silica, 1 weight %
hydrogen peroxide, 0.1 weight % EDTA and 0.25 weight % polyethylene
imine (PEI) were selectively used in an aluminum CMP process. The
results are shown in FIGS. 12A and 12B for a metal line of a first
device (FN73) and in FIGS. 13A and 13B for a metal line of a second
device (L13).
[0061] To test the effect of defect inhibitor including a chelating
agent, a conventional CMP slurry including 10 weight % colloidal
silica, 1 weight % hydrogen peroxide, 0.25 weight % PEI and 0.1
weight % EDTA, a slurry in accordance with an example embodiment of
the present invention including 10 weight % colloidal silica, 1
weight % hydrogen peroxide and 0.25 weight % PAMA and another
slurry in accordance with an example embodiment of the present
invention including 10 weight % colloidal silica, 1 weight %
hydrogen peroxide, 0.25 weight % PAMA, and 0.1 weight % EDTA were
selectively used in an aluminum CMP process. The results are shown
in FIGS. 14, 15, and 16, respectively.
[0062] Tests represented by FIGS. 14, 15, and 16 demonstrate a CMP
slurry including PAMA only as a defect inhibitor may result in
fewer defects overall than a conventional CMP slurry including PEI
and EDTA, but possibly more scratch defects. A CMP slurry including
PAMA and EDTA may further reduce scratch defects. As a result,
defects created in a metal surface by CMP polishing may be further
reduced by using a slurry that includes a first defect inhibitor,
such as PAMA, and a second defect inhibitor, such as EDTA.
[0063] Example embodiments of the present invention reduce or
prevent the formation of defects on a surface of a metal layer,
such as scratches, pits, corrosion, dishing and/or erosion by
forming a protective layer and/or decreasing the removal rate of
the metal layer.
[0064] In an example embodiment, a CMP slurry according to the
present invention may be usually used to polish the surface of a
metal layer so that metal wiring is maintained at the damascene
pattern, thus exposing the surface of an inter metal dielectric
layer. As shown in FIG. 17, an example method of performing CMP in
accordance with the present invention may include preparing a
slurry as described above including an abrasive, an oxidizer, and
at least one defect inhibitor at 1004 and performing CMP with the
slurry at 1006.
[0065] In an example embodiment, the removal rate selectivity of
the slurry is 20-1:1. In another example embodiment, the removal
rate selectivity of the slurry is 17-1.5:1.
[0066] In another example embodiment, a CMP slurry according to the
present invention may be usually used as a second CMP slurry to
polish the surface of a metal layer after a first CMP is performed
so that the metal wiring is maintained at the damascene pattern,
thus exposing the surface of the inter metal dielectric layer. As
shown in FIG. 18, an example method of performing CMP in accordance
with the present invention may include preparing a first slurry
including an abrasive and an oxidizer at 1000, performing CMP with
the first slurry at 1002, preparing a second slurry as described
above including an abrasive, an oxidizer, and at least one defect
inhibitor at 1004 and performing CMP with the second slurry at
1006.
[0067] In an example embodiment, the removal rate selectivity of
the first slurry is greater than removal rate selectivity of the
second slurry. In another example embodiment, the removal rate
selectivity of the first slurry is greater than 50:1 and the
removal rate selectivity of the second slurry is 20-1:1. In another
example embodiment, the removal rate selectivity of the second
slurry is 17-1.5:1.
[0068] FIGS. 19-21 illustrates the formation of an aluminum film
18, CMP polishing with a first CMP slurry, which may cause surface
defects, and polishing with a second CMP slurry, such as a slurry
in accordance with example embodiments of the present invention to
remove or reduce the surface defects caused by the first CMP
slurry.
[0069] In an example embodiment, a CMP slurry according to the
present invention may be used to form metal wiring. As shown in
FIG. 22, an example method of forming metal wiring in accordance
with the present invention may include forming an IMD layer, such
as IMD 12, at 1100, patterning the IMD layer at 1102, forming a
barrier metal layer, such as barrier metal layer 16, on the
patterned IMD layer at 1104, forming a metal film on barrier metal
layer, such as aluminum film 18, at 1106, and polishing the metal
film with a slurry including an abrasive, an oxidizer, and at least
one defect inhibitor at 1110.
[0070] In an example embodiment, the inter metal dielectric layer
is one of a silicon oxide layer and a silicon nitride layer. In
another example embodiment, the metal film is depositing by
sputtering or by chemical vapor deposition (CVD).
[0071] In an example embodiment, the removal rate selectivity of
the slurry is 20-1:1. In another example embodiment, the removal
rate selectivity of the slurry is 17-1.5:1.
[0072] In another example embodiment, a CMP slurry according to the
present invention may be usually used as a second CMP slurry to
polish the surface of a metal layer after a first CMP is performed
so that the metal wiring is maintained at the damascene pattern,
thus exposing the surface of the inter metal dielectric layer. As
shown in FIG. 23, an example method of forming metal wiring in
accordance with the present invention may include forming an IMD
layer, such as IMD 12, at 1100, patterning the IMD layer at 1102,
forming a barrier metal layer, such as barrier metal layer 16, on
the patterned IMD layer at 1104, forming a metal film on barrier
metal layer, such as aluminum film 18, at 1106, polishing the metal
film with a first slurry including an abrasive and an oxidizer at
1108, and polishing the metal film with a second slurry including
an abrasive, an oxidizer, and at least one defect inhibitor at
1110.
[0073] In an example embodiment, the inter metal dielectric layer
is one of a silicon oxide layer and a silicon nitride layer. In
another example embodiment, the metal film is depositing by
sputtering or by chemical vapor deposition (CVD).
[0074] In an example embodiment, the removal rate selectivity of
the first slurry is greater than removal rate selectivity of the
second slurry. In another example embodiment, the removal rate
selectivity of the first slurry is greater than 50:1 and the
removal rate selectivity of the second slurry is 20-1:1. In another
example embodiment, the removal rate selectivity of the second
slurry is 17-1.5:1.
[0075] In an example embodiment, the surface of the metal wiring
may be refined during the second polishing by removing defects such
as scratches, corrosions, and pits, are caused during the first
polishing.
[0076] Although example embodiments of the present invention set
forth above, describe polymeric compounds having a carboxyl group,
any compound that can generate anions, which adsorb onto the
surface of a metal layer, and/or hydrogen ions, which acidify the
CMP slurry solution would be suitable.
[0077] Although example embodiments of the present invention set
forth above, describe poly acrylic acid (PAA), poly acrylic acid co
maleic acid (PAMA), salts thereof, and mixtures thereof, any
compound having a carboxyl group that can generate anions, which
adsorb onto the surface of a metal layer, and/or hydrogen ions,
which acidify the CMP slurry solution would be suitable.
[0078] Although example embodiments of the present invention set
forth above, describe the abrasive as a silica, such as colloidal
silica and/or fumed silica, any abrasive would be suitable.
[0079] Although example embodiments of the present invention set
forth above, describe the oxidizer as hydrogen peroxide
(H.sub.2O.sub.2) and/or ammonium persulfate (NH4)
.sub.2S.sub.2O.sub.8, any oxidizer would be suitable.
[0080] Although example embodiments of the present invention set
forth above, describe the pH controller as one or more of
H.sub.3PO.sub.4, HNO.sub.3, and H.sub.2SO.sub.4, any pH controller
would be suitable.
[0081] Although example embodiments of the present invention set
forth above, describe the chelating agent as ethylene
diaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA),
diethylenetriaminepentaacetic acid (DTPA), hydroxyethyl ethylene
diaminetriacetic acid (HEDTA), methylglycinediacetic acid (MGDA),
salts thereof, and mixtures thereof, any chelating agent would be
suitable.
[0082] Example embodiments of the present invention may reduce
defects, such as scratches, pits, corrosion, erosion, and/or
dishing in a variety of areas. These areas may include areas where
features are more densely packed and other areas, such as bond
pads, with large open features. More specifically, these areas may
include areas with isolated thin lines, isolated wide lines, dense
thin lines, dense wide lines, or combinations thereof.
[0083] It will be apparent to those skilled in the art that other
changes and modifications may be made in the above-described
example embodiments without departing from the scope of the
invention herein, and it is intended that all matter contained in
the above description shall be interpreted in an illustrative and
not a limiting sense.
* * * * *