U.S. patent application number 11/544694 was filed with the patent office on 2007-03-01 for polishing liquid composition.
This patent application is currently assigned to KAO CORPORATION. Invention is credited to Toshiya Hagihara, Ryoichi Hashimoto, Yasuhiro Yoneda.
Application Number | 20070045233 11/544694 |
Document ID | / |
Family ID | 26510869 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070045233 |
Kind Code |
A1 |
Yoneda; Yasuhiro ; et
al. |
March 1, 2007 |
Polishing liquid composition
Abstract
A polishing liquid composition is applicable as a means of
forming embedded metal interconnections on a semiconductor
substrate. In a surface to be polished comprising an insulating
layer and a metal interconnection layer, the polishing liquid
composition is capable of maintaining a polishing speed of the
metal layer, of suppressing an etching speed, and of preventing
dishing of the metal layer.
Inventors: |
Yoneda; Yasuhiro;
(Wakayama-shi, JP) ; Hashimoto; Ryoichi;
(Wakayama-shi, JP) ; Hagihara; Toshiya;
(Wakayama-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
KAO CORPORATION
Chuo-ku
JP
|
Family ID: |
26510869 |
Appl. No.: |
11/544694 |
Filed: |
October 10, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10030424 |
Jan 10, 2002 |
7118685 |
|
|
PCT/JP00/04571 |
Jul 7, 2000 |
|
|
|
11544694 |
Oct 10, 2006 |
|
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Current U.S.
Class: |
216/88 ;
252/79.1; 252/79.4; 257/E21.304 |
Current CPC
Class: |
C09K 13/06 20130101;
C23F 3/04 20130101; C23F 3/06 20130101; H01L 21/31053 20130101;
H01L 21/3212 20130101; C23F 3/00 20130101; C09G 1/02 20130101 |
Class at
Publication: |
216/088 ;
252/079.1; 252/079.4 |
International
Class: |
C09K 13/00 20060101
C09K013/00; C09K 13/06 20060101 C09K013/06; B44C 1/22 20060101
B44C001/22; C03C 15/00 20060101 C03C015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 13, 1999 |
JP |
11-198263 |
Feb 8, 2000 |
JP |
2000-030477 |
Claims
1. A polishing liquid composition for polishing a surface to be
polished comprising an insulating layer and a metal layer, the
polishing liquid composition comprising a compound having six or
more carbon atoms and a structure in which each of two or more
adjacent carbon atoms has a hydroxyl group in a molecule, and
water, wherein the compound having a structure in which each of two
or more adjacent carbon atoms has a hydroxyl group in a molecule is
represented by the formula (I):
R.sup.1--X--(CH.sub.2).sub.q--[CH(OH)].sub.n--CH.sub.2OH (I)
wherein R.sup.1 is a hydrocarbon group having 1 to 12 carbon atoms;
X is a group represented by (CH.sub.2).sub.m, wherein m is 1,
oxygen atom, sulfur atom, COO group, OCO group, a group represented
by NR.sup.2 or O(R.sup.2O)P(O)O, wherein R.sup.2 is hydrogen atom
or a hydrocarbon group having 1 to 24 carbon atoms; q is 0 or 1;
and n is an integer of 1 to 4.
2. The polishing liquid composition according to claim 1, further
comprising an organic acid.
3. The polishing liquid composition according to claim 2, wherein
the organic acid is an etching agent.
4. The polishing liquid composition according to claim 1, further
comprising an etching agent comprising an inorganic acid.
5-6. (canceled)
7. The polishing liquid composition according to claim 1, further
comprising an oxidizing agent, an abrasive or a mixture
thereof.
8-10. (canceled)
11. A method of using a polishing liquid composition, the method
comprising polishing a surface using the polishing liquid
composition of claim 1.
12. The polishing liquid composition according to claim 2, further
comprising an oxidizing agent, an abrasive or a mixture
thereof.
13. A method of using a polishing liquid composition, the method
comprising polishing a surface using the polishing liquid
composition of claim 2.
14. A method of using a polishing liquid composition, the method
comprising polishing a surface using the polishing liquid
composition of claim 7.
15. A method of using a polishing liquid composition, the method
comprising polishing a surface using the polishing liquid
composition of claim 12.
16. A method of making a polishing liquid composition, the method
comprising mixing water and a compound having a molecular structure
in which each of two or more adjacent carbon atoms has a hydroxyl
group; and producing the polishing liquid composition of claim
1.
17. The polishing compound according to claim 1, wherein the
compound having a structure in which each of two or more adjacent
carbon atoms has a hydroxyl group in a molecule is selected from
the group consisting of 1,2-heptanediol, 1,2-hexanediol,
1,2-octanediol, 1,2,3-hexanetriol, 1,2,6-hexanetriol,
1,2,3-heptanetriol, glyceryl ethers, monoglycerides, partially
esterified products prepared by carrying out an esterification
reaction of gluconic acid with an alcohol, compounds prepared by
reacting glycidol with a monoalkylamine or a dialkylamine, diesters
of tartaric acid, and 1,2-cyclohexanediol.
Description
TECHNICAL FIELD
[0001] The present invention relates to a polishing liquid
composition for polishing a surface to be polished comprising an
insulating layer and a metal layer. More specifically, the present
invention relates to a polishing liquid composition which is
applicable as a means of forming embedded metal interconnection on
a semiconductor substrate, a process for polishing, and a process
for manufacturing a semiconductor substrate.
BACKGROUND ART
[0002] In the process for manufacturing a semiconductor device,
comprising the steps of forming interconnection-shaped recesses on
a surface of the insulating film on a semiconductor substrate,
sedimenting a metal film made of copper or the like on the
insulating film having the recesses, and subjecting the metal film
to polishing treatment by a polishing device and a polishing
liquid, thereby allowing the metal layer to remain only in the
recesses to form a metal interconnection layer, wherein Metal
Chemical Mechanical Polishing (hereinafter simply referred to as
"metal CMP") is employed for the process of polishing.
[0003] However, in the metal CMP, there arise grooves so-called
dishing on the metal interconnection layer in the recesses of the
insulating film, so that the cross-sectional area of the metal
interconnection layer is reduced, thereby causing an increase in
electric resistivity. This dishing is caused by more excessive
polishing or etching of the surface of the metal interconnection
layer than that of the insulating film surface by the polishing
liquid composition. Especially copper, one of the main metal
interconnection, has defects of being excessively etched by the
polishing liquid composition, so that the dishing is likely to be
caused.
[0004] Therefore, there has been desired a polishing liquid
composition free from defects such as dishing in the metal layer
during the formation of interconnection, with retaining an etching
action for polishing the metal film on the insulating film.
[0005] As a conventional polishing liquid, for instance, Japanese
Patent Laid-Open Nos. Hei 8-83780 and Hei 11-21546 each discloses a
polishing liquid comprising benzotriazole or a derivative thereof
as a protective film-forming agent for the metal surface in order
to prevent the dishing. Since the formed protective film is rigid,
when the metal layer is polished in the metal CMP, the polishing
speed would become insufficient. In addition, Japanese Patent
Laid-Open No. Hei 11-116942 discloses a composition for polishing,
comprising a compound having 1 to 10 alcoholic hydroxyl groups, or
a nitrogen-containing basic compound having 1 to 10 alcoholic
hydroxyl groups. This composition for polishing has a purpose of
reducing particles deposited on a wafer surface in final polishing
of the semiconductor wafer, so that the problems to be solved are
different.
[0006] In addition, Japanese Patent Laid-Open No. Hei 10-44047
discloses a polishing liquid comprising an aqueous medium, an
abrasive, an oxidizing agent, and an organic acid. However, since
the etching action is too strong, the prevention for dishing would
be insufficient. Further, Japanese Patent Laid-Open No. Hei
11-195628 discloses a process for polishing in which a polishing
liquid is used in combination with ammonium polyacrylate as a
substance for suppressing oxidation and etching. However, in the
metal CMP in which a metal layer made of copper or the like is
polished, there arises surface roughening of the copper surface
caused by ammonium polyacrylate.
[0007] An object of the present invention is to provide a polishing
liquid composition capable of maintaining a polishing speed of a
metal film, suppressing an etching speed, and having an excellent
prevention effect such as dishing of the metal interconnection
layer, in a surface to be polished comprising an insulating layer
and a metal layer; a process for polishing; and a process for
manufacturing a semiconductor substrate.
[0008] These objects and other objects of the present invention
will be apparent from the following description.
DISCLOSURE OF INVENTION
[0009] Specifically, the present invention relates to: [0010] [1] a
polishing liquid composition for polishing a surface to be polished
comprising an insulating layer and a metal layer, the polishing
liquid composition comprising a compound having a structure in
which each of two or more adjacent carbon atoms has a hydroxyl
group in a molecule, and water (hereinafter also referred to "the
polishing liquid composition 1-1"); [0011] [2] a polishing liquid
composition for polishing a surface to be polished comprising an
insulating layer and a metal layer, the polishing liquid
composition comprising an aliphatic carboxylic acid having 7 to 24
carbon atoms and/or a salt thereof, an etching agent, and water
(hereinafter also referred to "the polishing liquid composition
1-2"); [0012] [3] a polishing liquid composition for polishing a
surface to be polished comprising an insulating layer and a metal
layer, the polishing liquid composition comprising an amine
compound represented by the following general formula (II):
##STR1## wherein R.sup.3 is a linear or branched alkyl group having
4 to 18 carbon atoms, a linear or branched alkenyl group having 4
to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and
an aralkyl group having 7 to 18 carbon atoms; each of R.sup.4 and
R.sup.5, which may be identical or different, is hydrogen atom, a
linear alkyl group having 1 to 8 carbon atoms or a branched alkyl
group having 3 to 8 carbon atoms, or a group represented by
H--(OR.sup.6).sub.z--, wherein R.sup.6 is a linear alkylene group
having 1 to 3 carbon atoms, or a branched alkylene group having 3
carbon atoms; and Z is a number of 1 to 20, [0013] and/or a salt
thereof, an etching agent, and water (hereinafter also referred to
"the polishing liquid composition 1-3"); [0014] [4] the polishing
liquid composition according to any one of items [1] to [3] above,
further comprising an oxidizing agent (hereinafter also referred to
"the polishing liquid composition 2"); [0015] [5] the polishing
liquid composition according to any one of items [1] to [4] above,
further comprising an abrasive (hereinafter also referred to "the
polishing liquid composition 3"); [0016] [6] a process for
polishing a semiconductor substrate, comprising polishing a surface
to be polished comprising an insulating layer and a metal layer
using the polishing liquid composition of any one of items [1 to
[5], thereby smoothening the semiconductor substrate; and [0017]
[7] a process for manufacturing a semiconductor substrate
comprising polishing a surface to be polished comprising an
insulating layer and a metal layer using the polishing liquid
composition of any one of items [1] to [5], thereby smoothening the
semiconductor substrate.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] As mentioned above, the polishing liquid composition of the
present invention is a polishing liquid composition for polishing a
surface to be polished comprising an insulating layer and a metal
layer, and has the following three embodiments. [0019]
Embodiment 1: A polishing liquid composition comprising a compound
having a structure in which each of two or more adjacent carbon
atoms has a hydroxyl group in a molecule, and water.
[0019] [0020] Embodiment 2: A polishing liquid composition
comprising an aliphatic carboxylic acid having 7 to 24 carbon atoms
and/or a salt thereof, an etching agent and water. [0021]
Embodiment 3: A polishing liquid composition comprising an amine
compound represented by the following general formula (II):
##STR2## wherein R.sup.3 is a linear or branched alkyl group having
4 to 18 carbon atoms, a linear or branched alkenyl group having 4
to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and
an aralkyl group having 7 to 18 carbon atoms; and each of R.sup.4
and R.sup.5, which may be identical or different, is hydrogen atom,
a linear alkyl group having 1 to 8 carbon atoms or a branched alkyl
group having 3 to 8 carbon atoms, or a group represented by
H--(OR.sup.6).sub.z--, wherein R.sup.6 is a linear alkylene group
having 1 to 3 carbon atoms, or a branched alkylene group having 3
carbon atoms; and Z is a number of 1 to 20, [0022] and/or a salt
thereof, an etching agent, and water.
Embodiment 1
[0023] In this embodiment, one of the great features resides in the
use of a compound having a structure in which each of two or more
adjacent carbon atoms has a hydroxyl group in a molecule
(hereinafter simply referred to as "hydroxyl group-containing
compound"). By the use of the polishing liquid composition
comprising the hydroxyl group-containing compound, the polishing
speed can be maintained, and excessive etching of a metal film in
the metal layer can be prevented, so that there is exhibited an
excellent effect that a polishing surface without defects such as
dishing can be obtained.
[0024] In the hydroxyl group-containing compound, from the
viewpoint of maintaining the polishing speed and suppressing
dishing, the number of adjacent carbon atoms having a hydroxyl
group in a molecule is 2 or more, preferably from 2 to 10, more
preferably from 2 to 7, especially preferably from 2 to 4.
[0025] In addition, as the structure of the hydroxyl
group-containing compound, it is particularly preferable that the
structure in which each of two or more adjacent carbon atoms has a
hydroxyl group is present in the terminal portion of a
molecule.
[0026] Examples thereof include a compound represented by the
formula (I):
R.sup.1--X--(CH.sub.2).sub.q--[CH(OH)].sub.n--CH.sub.2OH (I)
wherein R.sup.1 is a hydrocarbon group having 1 to 24 carbon atoms;
X is a group represented by (CH.sub.2).sub.m, wherein m is 0 or 1,
oxygen atom, sulfur atom, COO group, OCO group, a group represented
by NR.sup.2 or O(R.sup.2O)P(O)O, wherein R.sup.2 is hydrogen atom
or a hydrocarbon group having 1 to 24 carbon atoms; q is 0 or 1;
and n is an integer of 1 to 4.
[0027] In the formula (I), the hydrocarbon group of R.sup.1 may be
either aliphatic or aromatic group, and the aliphatic group is
preferable. The structure of the aliphatic group may be saturated
or unsaturated, or linear or branched. From the viewpoint of
suppressing dishing, a saturated structure is preferable, and a
linear structure is preferable. In addition, the number of carbon
atoms of the above hydrocarbon groups is preferably 1 or more, from
the viewpoint of suppressing the dishing, and the number of carbon
atoms is preferably 24 or less, from the viewpoint of the
solubility of the compound represented by the formula (I) in water.
The number of carbon atoms is more preferably from 1 to 18, still
more preferably from 2 to 12. Each of m and q is preferably 1. The
number of carbon atoms of R.sup.2 is preferably 12 or less, more
preferably 8 or less, still more preferably 4 or less, from the
viewpoint of suppressing the dishing. Especially, R.sup.2 is
preferably hydrogen atom or methyl group. n is preferably 2 or
less, more preferably 1, from the viewpoint of suppressing the
dishing.
[0028] In addition, the hydroxyl group-containing compound may have
various functional groups other than hydroxyl group in a molecule.
From the viewpoints of maintaining the polishing speed and
suppressing the dishing, those compounds which do not contain
carboxyl group, sulfonate group, primary amino group or phenolic
hydroxyl group are preferable.
[0029] The hydroxyl group-containing compound has a molecular
weight of preferably 5000 or less, more preferably 1000 or less,
especially preferably 500 or less, from the viewpoints of
maintaining the polishing speed and suppressing the dishing.
[0030] The hydroxyl group-containing compound has an acid
dissociation constant pKa in an aqueous solution of preferably 8 or
more, more preferably 9 or more, especially preferably 10 or more,
from the viewpoints of maintaining the polishing speed and
suppressing the dishing. However, in a case where the hydroxyl
group-containing compound has two or more dissociable functional
groups in a molecule, pKa referred herein is a first dissociation
constant. In addition, the solubility of the hydroxyl
group-containing compound at a pH usable for a polishing liquid
composition is such that the compound dissolves preferably at 0.5%
by weight or more, more preferably at 1.0% by weight or more, in
water at 25.degree. C., from the viewpoint of formulating the
hydroxyl group containing compound in an aqueous medium.
[0031] Concrete examples of these hydroxyl group-containing
compounds include alkanediols such as 1,2-butanediol,
1,2-heptanediol, 1,2-hexanediol ("a" in Table 1 mentioned below),
and 1,2-octanediol; alkanetriols such as 1,2,3-hexanetriol,
1,2,6-hexanetriol, and 1,2,3-heptanetriol; glyceryl ethers such as
butyl glyceryl ether ("b" in Table 1 mentioned below), pentyl
glyceryl ether, hexyl glyceryl ether, and octyl glyceryl ether;
monoglycerides such as glyceryl monobutanoate, glyceryl
monopentanoate, glyceryl monohexanoate, glyceryl monoheptanoate
("c" in Table 1 mentioned below), and glyceryl monooctanoate;
partially esterified products prepared by carrying out
esterification reaction of gluconic acid and an alcohol such as
hexyl alcohol; compounds prepared by reacting glycidol with a
monoalkylamine such as hexylamine or a dialkylamine such as
dipropylamine ("d" in Table 1 mentioned below); diesters of
tartaric acid such as diethyl tartrate, dibutyl tartrate, dipropyl
tartrate ("e" in Table 1 mentioned below), and dihexyl tartrate;
1,2-cyclohexanediol, and the like. Among them, from the viewpoints
of maintaining the polishing speed and suppressing the dishing, the
alkanediols and the glyceryl ethers are preferable. These hydroxyl
group-containing compounds may be used alone or in admixture of two
or more kinds.
[0032] The amount of the hydroxyl group-containing compounds
formulated is preferably from 0.01 to 30% by weight, more
preferably from 0.05 to 5% by weight, still more preferably from
0.1 to 3% by weight, of the polishing liquid composition 1-1, from
the viewpoints of maintaining the polishing speed and suppressing
the dishing.
[0033] Water usable in this embodiment is used as a medium. Its
amount formulated is preferably from 60 to 99.99% by weight, more
preferably from 70 to 99.4% by weight, still more preferably from
80 to 99.0% by weight, of the polishing liquid composition 1-1,
from the viewpoint of efficiently polishing the substrate to be
polished.
[0034] The polishing liquid composition 1-1 of this embodiment
having the composition described above has a pH of preferably from
2 to 11, more preferably from 2 to 7, still more preferably from 2
to 6, especially preferably 3 to 5, from the viewpoints of keeping
a polishing speed at a practical level, suppressing the dishing,
and removing fine scratch damages on the surface. In order to
adjust the pH within the above ranges, an inorganic acid such as
nitric acid or sulfuric acid, an organic acid, a basic substance
such as potassium hydroxide, sodium hydroxide, ammonia, or an
organic amine can be appropriately added, as occasion demands.
[0035] In addition, the polishing liquid composition 1-1 of this
embodiment may further comprise an organic acid.
[0036] In this embodiment, since the organic acid is used, the
organic acid forms a complex with or binds to various metals,
especially copper, constituting the metal layer, so that the metal
layer is made brittle, whereby exhibiting an effect that the
removal of the metal layer is made easy during polishing.
[0037] In addition, especially, the organic acid can be used in
combination with a compound having a structure in which each of two
or more adjacent carbon atoms has a hydroxyl group in a molecule,
whereby maintaining the polishing speed and preventing the
dishing.
[0038] The organic acid is an organic compound showing acidic
property. These organic compounds showing acidic property include
those having functional groups such as carboxyl group, phosphonic
group, phosphinic group, sulfonic group, sulfinic group, phenol
group, enol group, thiophenol group, imido group, oxime group,
aromatic sulfamide groups, and primary and secondary nitro
groups.
[0039] The organic acid usable in this embodiment has a molecular
weight of preferably 1000 or less, more preferably 500 or less.
[0040] The organic acid having carboxyl group includes
monocarboxylic acids having 1 to 24 carbon atoms, dicarboxylic
acids, hydroxycarboxylic acids and aminocarboxylic acids are
preferable, from the viewpoint of the solubility in water. The
number of carbon atoms is more preferably 1 to 18 carbon atoms,
still more preferably 1 to 12 carbon atoms, especially preferably 1
to 8 carbon atoms, most preferably 1 to 6 carbon atoms. Concrete
examples thereof include monocarboxylic acids, such as formic acid,
acetic acid, propionic acid, butyric acid, valerianic acid, caproic
acid, and pyruvic acid; dicarboxylic acids such as oxalic acid,
malonic acid, succinic acid, glutaric acid, and adipic acid;
hydroxycarboxylic acids such as gluconic acid, tartaric acid,
glycolic acid, lactic acid, citric acid, and malic acid;
aminocarboxylic acid such as nitrilotriacetic acid. The organic
acid having phosphonic group includes aminotri(methylenephosphonic
acid), 1-hydroxyethylidene-1,1-diphosphonic acid,
ethylenediaminetetra(methylenephosphonic acid),
hexamethylenediaminetetra(methylenephosphonic acid),
diethylenetriaminepenta(methylenephosphonic acid); the organic acid
having phosphinic group includes ethyl phosphite, and the like; the
organic acid having sulfonic group includes methanesulfonic acid,
benzenesulfonic acid, ptoluenesulfonic acid, naphthalenesulfonic
acid, and the like; the organic acid having sulfinic group includes
benzenesulfinic acid, p-toluenesulfinic acid, and the like. Among
them, the organic acids having carboxyl group are preferable. More
concretely, monocarboxylic acids, dicarboxylic acids,
hydroxycarboxylic acids and aminocarboxylic acids are preferable,
and acetic acid, oxalic acid, succinic acid, glycolic acid, lactic
acid, citric acid, malic acid, tartaric acid, gluconic acid and
nitrilotriacetic acid are more preferable, and glycolic acid and
gluconic acid are still more preferable. These organic acids may be
used alone or in admixture of two or more kinds.
[0041] The organic acid is used in a state in which water is used
as a medium in the polishing liquid composition 1-1. The amount of
the organic acid formulated in the polishing liquid composition 1-1
can be widely selected for the purposes of securing the polishing
speed at a practical level to remove the metal layer, and
preventing excessive etching of the metal layer. The amount of the
organic acid formulated is, for instance, preferably from 0.1 to
10% by weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight.
[0042] In addition, among the above organic acids, a compound
capable of dissolving and etching a metal, especially copper in the
copresence of an aqueous medium, and having an etching speed "a" of
3 .ANG./min or more, as obtained by the following etching test A
can be used as an etching agent. Specifically, in the etching test
A, first a copper ribbon (commercially available from K.K. Nirako;
thickness: 0.10 mm, width: 6 mm) having a length of 100 mm is
furnished, and the surface dirt or the like is wiped of with a
sheet of paper. Thereafter, the copper ribbon is subjected to
ultrasonic cleaning for one minute in a state of being immersed in
normal hexane, and thereafter the surface is sufficiently degreased
and dried. Subsequently, its metal test piece is coiled into a
helical form so that an entire surface of the ribbon is immersed in
the polishing liquid, to give a metal test piece before test. The
weight before immersion is determined by accurate balance.
[0043] Next, the etching agent is diluted to give a 2% by weight
aqueous solution thereof. Further, 100 g of the etching solution of
which pH is adjusted to 8.+-.0.5 with aqueous ammonia is furnished
in a 150 cc beaker (K. K. Teraoka, 150 cc disposable cup), and the
above metal test piece is immersed at 25.degree. C. for 12 hours.
During immersion, the etching solution is stirred with a magnetic
stirrer, to an extent that the copper ribbon rotates along with the
flow of the etching solution. After the test, the copper ribbon
surface is sufficiently wiped off, and its weight is again
determined by accurate balance, to give a weight after the test.
The amount of reduced thickness of copper is calculated from the
weight loss of the copper ribbon before and after the test, and the
resulting amount is divided by the etching time period to determine
an etching speed "a." From the viewpoint of obtaining a practical
polishing speed, an etching agent having an etching speed "a"
obtainable from the above etching test of 3 .ANG./min or more is
preferable, more preferably 5 .ANG./min or more, still more
preferably 10 .ANG./min or more. The etching speed "a" in this case
may be an etching speed of two or more etching agents used in
combination.
[0044] In addition, as the etching agent, an inorganic acid which
is capable of dissolving and etching a metal, especially copper, in
the copresence of an aqueous medium, and having an etching speed
"a" obtainable from the above etching test A of 3 .ANG./min or more
can be used.
[0045] Among the organic acids, from the viewpoint of having an
appropriate etching speed, preferable etching agents include one or
more compounds selected from the group consisting of the following
A to D. Also, the following inorganic acids E are usable as an
etching agent. [0046] A: aliphatic organic acids having 6 or less
carbon atoms and one to three carboxyl groups; [0047] B: aromatic
organic acids having 7 to 10 carbon atoms and one to four carboxyl
groups; [0048] C: organic acids having 6 or less carbon atoms and
one to four phosphonic groups; [0049] D: polyaminocarboxylic acids
having in a molecule two or more structures represented by the
formula (III): ##STR3## and [0050] E: inorganic acids.
[0051] Concretely, the aliphatic organic acid of the group A having
6 or less carbon atoms and one to three carboxyl groups includes
monocarboxylic adds, such as formic acid, acetic acid, and
propionic acid; polycarboxylic acids, such as oxalic acid, malonic
acid, succinic acid, glutaric acid, adipic acid, and tricarballylic
acid; hydroxycarboxylic acids such as glycolic add, lactic acid,
2-hydroxypropionic acid, malic acid, tartaric acid, citric acid,
and gluconic add; amino acids such as glycine, alanine, and
aspartic add; and the like. The aromatic organic acid of the group
B having 7 to 10 carbon atoms and one to four carboxyl groups
includes benzoic acid, phthalic acid, trimellitic add, pyromellitic
acid, mandelic add, salicylic add, and the like. The organic acid
of the group C having 6 or less carbon atoms and one to four
phosphonic groups includes phosphonic adds such as methylphosphonic
add and phenylphosphonic add; phosphinic acids such as
methylphosphinic acid and phenylphosphinic acid; phosphonic acid
esters such as methyl ester of phosphonic acid; aminophosphonic
acids such as aminotri(methylenephosphonic add) and
1-hydroxyethylidene-1-diphosphonic acid; and the like. The
polyaminocarboxylic acid of the group D having in a molecule two or
more structures represented by the formula (III) includes
ethylenediaminetetraacetic acid, nitrilotriacetic add,
diethylenediaminepentaacetic acid, triethylenetetraminehexaacetic
acid, hydroxyethylethylenediaminetetraacetic acid, and the like.
The inorganic acid of the group E includes hydrochloric acid,
perchloric acid, sulfuric acid, nitric acid, phosphoric acid,
phosphonic acid, phosphinic acid, and the like. Among them, from
the viewpoint of the polishing speed, preferable are the
polycarboxylic acids or hydroxycarboxylic acids belonging to the
group A or B; aminophosphonic acids belonging to the group C;
polyaminocarboxylic acids of the group D having in a molecule two
or more structures represented by the formula (III); and
hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid
belonging to the group E. More preferable are oxalic acid, succinic
acid, glycolic acid, lactic acid, citric acid, malic acid, gluconic
acid, phthalic acid, aminotri(methylenephosphonic acid),
1-hydroxyethylidene-1-diphosphonic acid, ethylenediaminetetraacetic
acid, hydrochloric acid, and sulfuric acid. These etching agents
may be used alone or in admixture of two or more kinds. In this
embodiment, glycolic acid and gluconic acid are especially
preferable.
[0052] These etching agents, for instance, have the following
etching speed "a": Glycolic acid, 60 .ANG./min; citric acid, 25
.ANG./min; phthalic acid, 50 .ANG./min;
aminotri(methylenephosphonic acid), 10 .ANG./min;
ethylenediaminetetraacetic acid, 30 .ANG./min; acetic acid, 70
.ANG./min, glycine, 40 .ANG./min; hydrochloric acid, 400 .ANG./min;
and sulfuric acid, 100 .ANG./min.
[0053] When the etching agent usable in this embodiment is used in
the preparation of a polishing liquid composition, with proviso
that the composition does not comprise the hydroxyl
group-containing compound, in which an oxidizing agent, abrasive
grains, and the like are further copresent, it is preferable to
adjust the kinds, contents, and the like, so that the etching
liquid composition has an etching speed "b" obtainable from the
following etching test B of 20 .ANG./min or more. The etching test
B is carried out in the same procedures as in the etching test A,
except that the copper ribbon is immersed in a polishing liquid
composition comprising, as an etching solution of the etching test
A, water, an abrasive and an etching agent, and, if necessary, an
oxidizing agent, at room temperature (25.degree. C.) for 2 hours,
and that the pH is adjusted to 4.0.+-.0.5. The etching speed
obtained by the etching test B is referred to as "etching speed
`b`." From the viewpoint of obtaining a practical polishing speed,
the etching speed "b" obtainable from the above etching test B is
preferably 20 .ANG./min or more, more preferably 30 .ANG./min or
more, still more preferably 50 .ANG./min or more. The etching speed
"b" in this case may be an etching speed of a polishing liquid
composition in which two or more etching agents are used in
combination.
[0054] In this embodiment, since the etching agent is used, the
etching agent forms a complex with or binds to various metals,
especially copper, constituting the metal layer, so that the
removal of the metals is made easy as water-soluble salts and/or
chelated compounds, whereby exhibiting an effect that the polishing
speed of the metal layer is increased during polishing.
[0055] The amount of the etching agent formulated in the polishing
liquid composition 1-1 can be variously selected in order to secure
the polishing speed at a practical level to remove the metal layer,
and to prevent excessive etching of the metal layer. The amount of
the etching agent formulated is preferably from 0.1 to 10% by
weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight, of the polishing liquid
composition 1-1.
Embodiment 2
[0056] In this embodiment, one of the largest features resides in
that the above aliphatic carboxylic acid having 7 to 24 carbon
atoms and/or a salt thereof and the etching agent are used in
combination. Since the aliphatic carboxylic acid having 7 to 24
carbon atoms and/or a salt thereof has an action of lowering the
etching speed, the polishing speed at a practical level can be
maintained and excessive etching of the metal film in the metal
layer can be prevented by the use of a polishing liquid composition
comprising these compounds and the etching agent. Therefore, there
is exhibited an excellent effect that the polishing surface without
defects such as dishing can be obtained.
[0057] From the viewpoints of maintaining the polishing speed and
suppressing the dishing, the aliphatic carboxylic acid and/or a
salt thereof has 7 to 24 carbon atoms. Further, from the viewpoints
of keeping the solubility in the polishing liquid, the
low-foamability, and the polishing speed at practical levels, and
suppressing the dishing, these compounds have preferably from 7 to
20 carbon atoms, more preferably from 7 to 16 carbon atoms, still
more preferably from 7 to 12 carbon atoms, especially preferably
from 7 to 10 carbon atoms.
[0058] In addition, the hydrocarbon group of the aliphatic
carboxylic acid and/or a salt thereof may be saturated or
unsaturated, or linear or branched.
[0059] In addition, the salts of the aliphatic carboxylic acids may
be any of ammonium salts, salts of organic amines, and alkali metal
salts. From the viewpoint of preventing staining of the
semiconductors, ammonium salts, and salts of organic amines such as
salts of monoethanolamine, salts of diethanolamine, salts of
triethanolamine, and salts of triethylamine.
[0060] Concrete examples of these aliphatic carboxylic acids and
salts thereof include linear, saturated aliphatic carboxylic acids
such as heptanoic acid, octanoic acid, nonanoic acid, decanoic
acid, lauric acid, myristic acid, palmitic acid, stearic acid, and
eicosanoic add; linear, unsaturated aliphatic carboxylic acids such
as heptenoic acid, octenoic add, decenoic acid, dodecenoic, and
oleic acid; branched, saturated aliphatic carboxylic acids such as
2-methylhexanoic acid, 2-ethylhexanoic acid, 3,5-dimethylhexanoic
acid, 3,5,5-trimethylhexanoic acid, and isodecanoic acid; and
ammonium salts, salts of organic amines, alkali metal salts of
these aliphatic carboxylic acids, and the like. Among them, from
the viewpoints of the polishing speed and the suppression of the
dishing, the linear or branched, saturated aliphatic carboxylic
acids and ammonium salts thereof are preferable, and from the
viewpoint of the solubility in the polishing liquid and the low
foamability, heptanoic acid or ammonium salt thereof, octanoic acid
or ammonium salt thereof, nonanoic add or ammonium salt thereof,
and decanoic acid or ammonium salt thereof are especially
preferable. These aliphatic carboxylic acids having 7 to 24 carbon
atoms and salts thereof may be used alone or in admixture of two or
more kinds.
[0061] The amount of the aliphatic carboxylic acid and a salt
thereof formulated is preferably from 0.01 to 30% by weight, more
preferably from 0.02 to 10% by weight, still more preferably from
0.03 to 5% by weight, of the polishing liquid composition 1-2, from
the viewpoint of maintaining the polishing speed, and suppressing
the dishing.
[0062] The etching agent usable in this embodiment is capable of
dissolving and etching a metal, especially copper, in the
copresence of an aqueous medium, and is a compound having an
etching speed "a" of 3 .ANG./min or more, as obtained by the
etching test A described in Embodiment 1. From the viewpoint of
obtaining a practical polishing speed, an etching agent having an
etching speed "a" obtainable from the above etching test A of 3
.ANG./min or more is preferable, more preferably 5 .ANG./min or
more, still more preferably 10 .ANG./min or more. The etching speed
"a" in this case may be an etching speed of two or more etching
agents used in combination.
[0063] Preferable etching agents include the same ones as those in
Embodiment 1 mentioned above. These etching agents may be used
alone or in admixture of two or more kinds. In this embodiment,
glycolic acid, citric acid, and aminotri(methylenephosphonic acid)
are especially preferable. Incidentally, the etching speed "a" of
the aliphatic carboxylic acid having 7 to 24 carbon atoms is 2
.ANG./min or less, and as compared to the etching agent, the
etching strength is none or almost not found.
[0064] When the etching agent usable in this embodiment is used in
the preparation of a polishing liquid composition, with proviso
that the composition does not comprise the aliphatic carboxylic
acid having 7 to 24 carbon atoms and/or a salt thereof, in which an
oxidizing agent, abrasive grains, and the like are further
copresent, it is preferable to adjust the kinds, contents, and the
like, so that the polishing liquid composition has an etching speed
"c" obtainable from the following etching test C of 20 .ANG./min or
more. The etching test C is carried out in the same procedures as
in the etching test A, except that the copper ribbon is immersed in
a polishing liquid composition comprising, as an etching solution
of the etching test A, water, an abrasive and an etching agent,
and, if necessary, an oxidizing agent, at room temperature
(25.degree. C.) for 2 hours. The etching speed obtained by the
etching test C is referred to as "etching speed `c`." From the
viewpoint of obtaining a practical polishing speed, the etching
speed "c" obtainable from the above etching test C is preferably 20
.ANG./min or more, more preferably 30 .ANG./min or more, still more
preferably 50 .ANG./min or more. The etching speed "c" in this case
may be an etching speed of a polishing liquid composition in which
two or more etching agents are used in combination.
[0065] In this embodiment, since the etching agent is used, the
etching agent forms a complex with or binds to various metals,
especially copper, constituting the metal layer, so that the
removal of the metals is made easy as water-soluble salts and/or
chelated compounds, whereby exhibiting an effect that the polishing
speed of the metal layer is increased during polishing.
[0066] The amount of the etching agent formulated in the polishing
liquid composition 1-2 can be variously selected in order to secure
the polishing speed at a practical level to remove the metal layer,
and to prevent excessive etching of the metal layer. The amount of
the etching agent formulated is preferably from 0.1 to 10% by
weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight, of the polishing liquid
composition 1-2.
[0067] Water usable in this embodiment is used as a medium. The
amount of water formulated is preferably from 60 to 99.89% by
weight, more preferably from 70 to 99.4% by weight, still more
preferably from 80 to 99% by weight, of the polishing liquid
composition 1-2, from the viewpoint of efficiently polishing the
substrate to be polished.
[0068] The polishing liquid composition 1-2 of this embodiment
having the composition described above has a pH of preferably 10 or
less, more preferably from 2 to 9.5, still more preferably from 4
to 9, especially preferably from 7 to 9, from the viewpoints of
keeping a polishing speed at a practical level, suppressing the
dishing, and removing fine scratch damages on the surface. In order
to adjust the pH within the above ranges, an inorganic acid such as
nitric acid or sulfuric acid; an organic acid; a basic substance
such as potassium hydroxide, sodium hydroxide, ammonia, or an
organic amine can be appropriately added, as occasion demands.
Embodiment 3
[0069] In this embodiment, one of the largest features resides in
that the above amine compound represented by the general formula
(II) and/or a salt thereof and the etching agent are used in
combination. The polishing speed at a practical level can be
maintained and excessive etching of the metal film of the metal
layer can be prevented by the use of a polishing liquid composition
comprising the amine compound and/or a salt thereof, and the
etching agent. Therefore, there is exhibited an excellent effect
that the polishing surface without defects such as dishing can be
obtained.
[0070] The above amine compound represented by the general formula
(II) and/or a salt thereof usable in this embodiment is preferable,
from the viewpoints of maintaining the polishing speed and
suppressing the dishing. Further, from the viewpoints of keeping
the low foamability and the polishing speed at practical levels and
suppressing the dishing, in the formula, R.sup.3 is preferably a
linear or branched, alkyl or alkenyl group having 5 to 14 carbon
atoms, more preferably a linear or branched, alkyl or alkenyl group
having 6 to 12 carbon atoms, still more preferably a linear or
branched, alkyl or alkenyl group having 7 to 10 carbon atoms. Each
of R.sup.4 and R.sup.5 is preferably hydrogen, a linear alkyl group
having 1 or 2 carbon atoms, a group represented by
H--(OR.sup.6).sub.z--, wherein R.sup.6 is an alkylene group having
2 carbon atoms and Z is a number from 1 to 4, and more preferably
hydrogen atom, methyl group and hydroxyethyl group.
[0071] In addition, the salt of the amine compound may be either a
salt with an inorganic acid or a salt with an organic acid, and
those which are a salt with an inorganic acid or organic acid which
is usable as an etching agent are preferable. Further, from the
viewpoint of preventing staining of the semiconductor, salts of
organic acids are more preferable among the etching agents.
[0072] Concrete examples of these amine compounds and salts thereof
include linear monoalkylamines such as butylamine, pentylamine,
hexylamine, heptylamine, octylamine, nonylamine, decylamine,
laurylamine, myristylamine, and stearylamine; linear
monoalkenylamines such as oleylamine; branched monoalkylamines such
as 2-ethylhexylamine; dialkylamines such as dihexylamine and
dioctylamine; trialkylamines such as dimethyloctylamine,
dimethyldecylamine, and dimethyldodecylamine; alkylalkanolamines
such as octyldiethanolamine, decyldiethanolamine, and
dodecyldiethanolamine; and carboxylates, phosphates,
hydrochlorides, sulfates, nitrates, and the like of these amine
compounds. Among them, from the viewpoints of maintaining the
polishing speed and suppressing the dishing, monoalkylamines,
monoalkyldimethylamines, and monoalkyldiethanolamines, each of
which is linear or branched, and carboxylates thereof are
preferable. Further, from the viewpoint of the low foamability,
more preferable are heptylamine, octylamine, nonylamine,
dimethyloctylamine, dimethyldecylamine, dimethyldodecylamine
octyldiethanolamine, decyldiethanolamine, and carboxylates thereof.
These amine compounds and salts thereof may be used alone or in
admixture of two or more kinds.
[0073] The amount of the amine compound and a salt thereof
formulated is preferably from 0.01 to 30% by weight, more
preferably from 0.02 to 10% by weight, still more preferably from
0.03 to 5% by weight, of the polishing liquid composition 1-3, from
the viewpoint of maintaining the polishing speed, and suppressing
the dishing.
[0074] The etching agent usable in this embodiment is capable of
dissolving and etching a metal, especially copper, in the
copresence of an aqueous medium, and is a compound having an
etching speed "a" of 3 .ANG./min or more, as obtained by the
etching test A described in Embodiment 1. From the viewpoint of
obtaining a practical polishing speed, an etching agent having an
etching speed "a" obtainable from the above etching test A of 3
.ANG./min or more is preferable, more preferably 5 .ANG./min or
more, still more preferably 10 .ANG./min or more. The etching speed
"a" in this case may be an etching speed of two or more etching
agents used in combination.
[0075] Preferable etching agents include the same ones as those in
Embodiment 1 mentioned above. These etching agents may be used
alone or in admixture of two or more kinds. In this embodiment,
glycolic acid, citric acid, and aminotri(methylenephosphonic acid)
are especially preferable.
[0076] When the etching agent usable in this embodiment is used in
the preparation of a polishing liquid composition, with proviso
that the composition does not comprise the above amine compound or
a salt thereof, in which an oxidizing agent, abrasive grains, and
the like are further copresent, it is preferable to adjust the
kinds, contents, and the like, so that the polishing liquid
composition has an etching speed "c" obtainable from the etching
test C described in Embodiment 2 of 20 .ANG./min or more. From the
viewpoint of obtaining a practical polishing speed, the etching
speed "c" obtainable from the above etching test C is preferably 20
.ANG./min or more, more preferably 30 .ANG./min or more, still more
preferably 50 .ANG./min or more. The etching speed "c" in this case
may be an etching speed of a polishing liquid composition in which
two or more etching agents are used in combination.
[0077] In this embodiment, since the etching agent is used, the
etching agent forms a complex with or binds to various metals,
especially copper, constituting the metal layer, so that the
removal of the metals is made easy as water-soluble salts and/or
chelated compounds, whereby exhibiting an effect that the polishing
speed of the metal layer is increased during polishing.
[0078] The amount of the etching agent formulated in the polishing
liquid composition 1-3 can be variously selected in order to secure
the polishing speed at a practical level to remove the metal layer,
and to prevent excessive etching of the metal layer. The amount of
the etching agent formulated is preferably from 0.1 to 10% by
weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight, of the polishing liquid
composition 1-3.
[0079] Water usable in this embodiment is used as a medium. The
amount thereof is preferably from 60 to 99.89% by weight, more
preferably from 70 to 99.4% by weight, still more preferably from
80 to 99% by weight, of the polishing liquid composition 1-3, from
the viewpoint of efficiently polishing the substrate to be
polished.
[0080] The polishing liquid composition 1-3 of this embodiment
having the composition described above has a pH of preferably 10 or
less, more preferably from 2 to 9.5, still more preferably from 4
to 9, especially preferably from 5 to 9, from the viewpoints of
keeping a polishing speed at a practical level, suppressing the
dishing, and removing fine scratch damages on the surface. In order
to adjust the pH within the above ranges, an inorganic acid such as
nitric acid or sulfuric acid, an organic acid, a basic substance
such as potassium hydroxide, sodium hydroxide, ammonia, or an
organic amine can be appropriately added, as occasion demands.
[0081] The polishing liquid composition 2 comprises one of the
polishing liquid compositions 1-1 to 1-3 (hereinafter collectively
referred to as "the polishing liquid composition 1"), and further
comprising an oxidizing agent. The oxidizing agent usable in the
present invention refers to those oxidizing a metal. In the present
invention, it is thought that the metal layer is oxidized by the
use of the oxidizing agent, whereby an effect of accelerating the
mechanical polishing effect of the metal layer is exhibited.
[0082] The oxidizing agent includes, peroxides; permanganic acid or
salts thereof, chromic acid or salts thereof, nitric acid or salts
thereof, peroxo acid or salts thereof, oxyacid or salts thereof
metal salts; sulfuric acid, and the like.
[0083] As concrete examples thereof, the peroxide includes hydrogen
peroxide, sodium peroxide, barium peroxide, and the like; the
permanganic acid or salts thereof include potassium permanganate,
and the like; chromic acid or salts thereof include metal salts of
chromic acid, metal salts of dichromic acid, and the like; the
nitrates include iron (III) nitrate, ammonium nitrate, and the
like; the peroxo acid or salts thereof include peroxodisulfuric
acid, ammonium peroxodisulfate, metal salts of peroxodisulfuric
acid, peroxophosphoric acid, peroxosulfuric acid, sodium
peroxoborate, performic acid, peracetic acid, perbenzoic acid,
perphthalic acid, and the like; the oxyacid or salts thereof
include hypochlorous acid, hypobromous acid, hypoiodous acid,
chloric acid, bromic acid, iodic acid, perchloric acid, sodium
hypochlorite, calcium hypochlorite, and the like; metal salts
include iron (III) chloride, iron (III) sulfate, iron (III)
citrate, ammonium iron (III) sulfate, and the like. Among the
oxidizing agents, hydrogen peroxide, iron (III) nitrate, peracetic
acid, ammonium peroxodisulfate, iron (III) sulfate and ammonium
iron (III) sulfate are preferable, and especially hydrogen peroxide
is preferable. These oxidizing agents may be used alone or in
admixture of two or more kinds.
[0084] The oxidizing agent is used in a state in which water is
used as a medium in the polishing liquid composition 2. The amount
of the oxidizing agent formulated is preferably from 0. 1 to 60% by
weight, more preferably from 0.2 to 50% by weight, still more
preferably from 0.3 to 30% by weight, especially preferably from
0.3 to 10% by weight, of the polishing liquid composition 2, from
the viewpoint of obtaining the polishing speed at a practical level
by rapid oxidation of the metal layer.
[0085] In addition, when the polishing liquid composition 2 is
prepared from the polishing liquid composition 1-1, the amount of
the hydroxyl group-containing compound formulated is preferably
from 0.01 to 30% by weight, more preferably from 0.05 to 5% by
weight, still more preferably from 0.1 to 3% by weight, of the
polishing liquid composition 2. The amount of water formulated is
preferably from 40 to 99.89% by weight, more preferably from 70 to
99.4% by weight, still more preferably from 80 to 99% by weight, of
the polishing liquid composition 2. The pH of the polishing liquid
composition 2 having the above composition, which is the same as
the polishing liquid composition 1-1, is preferably from 2 to 11,
more preferably from 2 to 7, still more preferably 2 to 6,
especially preferably from 3 to 5, from the viewpoints of keeping
the polishing speed at a practical level, suppressing the dishing,
and removing the fine scratch damages on the surface. In order to
adjust the pH to the above-specified range, there may be added at
an appropriate timing an inorganic acid such as nitric acid or
sulfuric acid, an organic acid, or a basic substance such as
potassium hydroxide, sodium hydroxide, ammonia, or an organic
amine.
[0086] In addition, when the polishing liquid composition 2 is
prepared from the polishing liquid composition 1-2, the amount of
the aliphatic carboxylic acid having 7 to 24 carbon atoms and/or
salts thereof formulated is preferably from 0.01 to 30% by weight,
more preferably from 0.02 to 10% by weight, still more preferably
from 0.03 to 5% by weight, of the polishing liquid composition 2.
The amount of the etching agent formulated is preferably from 0.1
to 10% by weight, more preferably from 0.2 to 8% by weight, still
more preferably from 0.3 to 5% by weight, of the polishing liquid
composition 2. The amount of water formulated is preferably from
39.89 to 99.79% by weight, more preferably from 70 to 99.4% by
weight, still more preferably from 80 to 99% by weight, of the
polishing liquid composition 2. The pH of the polishing liquid
composition 2 having the above composition, which is the same as
the polishing liquid composition 1-2, is preferably 10 or less,
more preferably from 2 to 9.5, still more preferably 4 to 9,
especially preferably from 7 to 9, from the viewpoints of keeping
the polishing speed at a practical level, suppressing the dishing,
and removing the fine scratch damages on the surface.
[0087] In addition, when the polishing liquid composition 2 is
prepared from the polishing liquid composition 1-3, the amount of
the amine compound and/or salts thereof formulated is preferably
from 0.01 to 30% by weight, more preferably from 0.02 to 10% by
weight, still more preferably from 0.03 to 5% by weight, of the
polishing liquid composition 2. The amount of the etching agent
formulated is preferably from 0.1 to 10% by weight, more preferably
from 0.2 to 8% by weight, still more preferably from 0.3 to 5% by
weight, of the polishing liquid composition 2. The amount of water
formulated is preferably from 39.89 to 99.79% by weight, more
preferably from 70 to 99.4% by weight, still more preferably from
80 to 99% by weight, of the polishing liquid composition 2. The pH
of the polishing liquid composition 2 having the above composition,
which is the same as the polishing liquid composition 1-3, is
preferably 10 or less, more preferably from 2 to 9.5, still more
preferably 4 to 9, especially preferably from 5 to 9, from the
viewpoints of keeping the polishing speed at a practical level,
suppressing the dishing, and removing the fine scratch damages on
the surface.
[0088] The polishing liquid compositions 1 and 2 of the present
invention are effective for polishing processes using a fixed
grinding wheel, a polishing pad in which abrasive grains are fixed
to the pad, and the like. For instance, by the use of the polishing
liquid compositions 1 and 2 of the present invention during
polishing in the polishing process using the fixed grinding wheel,
the polishing speed can be maintained, and the dishing of the metal
layer can be suppressed.
[0089] The polishing liquid composition 3 of the present invention
is one further comprising an abrasive to a polishing liquid
composition 1 or 2, which is usable for a polishing process by
loose abrasives.
[0090] As the abrasive, abrasives generally employed for polishing
can be used. The abrasive includes, for instance, metals, carbides
of metals or metalloids, nitrides of metals or metalloids, oxides
of metals or metalloids, borides of metals or metalloids, diamond,
and the like. The metals or metalloids include those elements
belonging to the Groups 3A, 4A, 5A, 3B, 4B, 5B, GB, 7B or 8B of the
Periodic Table. Examples thereof include silicon dioxide, aluminum
oxide, cerium oxide, titanium oxide, zirconium oxide, silicon
nitride, manganese dioxide, silicon carbide, zinc oxide, diamond,
and magnesium oxide. Among them, silicon dioxide, aluminum oxide
and cerium oxide are preferable. As concrete examples thereof, the
silicon dioxide includes colloidal silica particles, fumed silica
particles, surface-modified silica particles, and the like; the
aluminum oxide includes .alpha.-alumina particles, .gamma.-alumina
particles, .delta.-alumina particles, .theta.-alumina particles,
.eta.-alumina particles, amorphous alumina particles, and other
fumed alumina or colloidal alumina prepared by different process;
the cerium oxide includes ones having oxidation state of 3 or 4, of
which crystal system is hexagonal system, isometric system, or
face-centered cubic system, and the like. The silicon dioxide is
especially preferable. These abrasives may be used alone or in
admixture of two or more kinds.
[0091] The abrasive has a primary average particle size of
preferably from 5 to 1000 nm, more preferably from 10 to 500 nm,
still more preferably from 20 to 300 nm, especially preferably from
50 to 200 nm, most preferably from 50 to 100 nm. The lower limit of
the average particle size is preferably 5 nm or more, from the
viewpoint of maintaining a given polishing speed, and the upper
limit thereof is preferably 1000 nm or less, form the viewpoint of
preventing the generation of scratches on the surface of the
substrate to be polished.
[0092] Especially when the silicon dioxide is used as an abrasive,
the silicon dioxide has a primary average particle size of 5 nm or
more, preferably 10 nm or more, more preferably 20 nm or more, from
the viewpoint of 20 improving the polishing speed.
[0093] Incidentally, the primary average particle size of the
abrasive is determined by adding 0.1 g of the abrasive to 100 g of
a 0.1% aqueous solution of sodium polystyrenesulfonate, thereafter
applying ultrasonic waves, to disperse the abrasive, and measuring
image analysis of the dispersion by observing with a transmission
electron microscope.
[0094] When the polishing liquid composition 3 is used when forming
interconnection of a semiconductor device, especially preferably
usable abrasives are silica particles having purity of preferably
98% by weight or more, more preferably 99% by weight or more,
especially preferably 99.9% by weight or more. The abrasive
includes fumed silica prepared by subjecting a volatile silicon
compound such as silicon tetrachloride to high-temperature
hydrolysis in oxyhydrogen flame; or colloidal silica obtained by a
process in which an alkali silicate or ethyl silicate is used as a
starting material.
[0095] Incidentally, the purity of the above abrasive is obtained
as follows. Specifically, the purity can be determined I y
dissolving 1 to 3 g of an abrasive in an acid or an aqueous alkali,
and quantifying silicon ions by ICP (plasma emission analysis).
[0096] The abrasive is used in a so-called "slurry state" using
water as a medium in the polishing liquid composition 3. The amount
of the abrasive formulated in the polishing liquid composition 3
can be variously selected depending upon the viscosity of the
polishing liquid composition and the required quality of the
substrate to be polished, and the like. The amount of the abrasive
formulated is preferably from 0.01 to 30% by weight, more
preferably from 0.02 to 20% by weight, still more preferably from
0.1 to 20% by weight, especially preferably from 1.0 to 10% by
weight, of the polishing liquid composition 3.
[0097] In addition, when the polishing liquid composition 3 is
prepared from the polishing liquid composition 1-1 (hereinafter
referred to as "polishing liquid composition 3-1"), the amount of
the hydroxyl-group containing compound formulated is preferably
from 0.01 to 30% by weight, more preferably from 0.05 to 5% by
weight, still more preferably from 0.1 to 3% by weight, of the
polishing liquid composition 3-1, from the viewpoints of
maintaining the polishing speed and suppressing the dishing.
[0098] The amount of the organic acid formulated in the polishing
liquid composition 3-1 can be variously selected in order to secure
a polishing speed at a practical level for removal of the metal
layer, and to prevent excessive etching of the metal layer. The
amount is, for instance, preferably from 0.1 to 10% by weight, more
preferably from 0.2 to 8% by weight, still more preferably from 0.3
to 5% by weight, of the polishing liquid composition 3-1.
[0099] The amount of the oxidizing agent formulated is preferably
from 0.1 to 60% by weight, more preferably from 0.2 to 50% by
weight, still more preferably from 0.3 to 30% by weight, of the
polishing liquid composition 3-1, from the viewpoint of obtaining a
polishing speed at a practical level by rapid oxidation of the
metal layer.
[0100] The amount of water formulated is preferably from 40 to
99.98% by weight, more preferably from 60 to 99.4% by weight, still
more preferably from 75 to 99% by weight, of the polishing liquid
composition 3-1. The pH of the polishing liquid composition 3-1
having the above composition, which is the same as the polishing
liquid composition 1-1, is preferably from 2 to 11, more preferably
from 2 to 7, still more preferably 2 to 6, especially preferably
from 3 to 5, from the viewpoints of keeping the polishing speed at
a practical level, suppressing the dishing, and removing the fine
scratch damages on the surface.
[0101] In addition, when the polishing liquid composition 3 is
prepared from the polishing liquid composition 1-2 (hereinafter
referred to as "polishing liquid composition 3-2"), the amount of
the aliphatic carboxylic acid having 7 to 24 carbon atoms and/or
salts thereof formulated is preferably from 0.01 to 30% by weight,
more preferably from 0.02 to 10% by weight, still more preferably
from 0.03 to 5% by weight, of the polishing liquid composition 3-2,
from the viewpoints of maintaining the polishing speed and
suppressing the dishing.
[0102] The amount of the etching agent formulated in the polishing
liquid composition 3-2 can be variously selected in order to secure
a polishing speed at a practical level for removal of the metal
layer, and to prevent excessive etching of the metal layer. The
amount formulated is, for instance, preferably from 0.1 to 10% by
weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight, of the polishing liquid
composition 3-2.
[0103] The amount of the oxidizing agent formulated is preferably
from 0.1 to 60% by weight, more preferably from 0.2 to 50% by
weight, still more preferably from 0.3 to 30% by weight, especially
preferably from 0.3 to 10% by weight, of the polishing liquid
composition 3-2, from the viewpoint of obtaining a polishing speed
at a practical level by rapid oxidation of the metal layer.
[0104] The amount of water formulated is preferably from 39.88 to
99.88% by weight, more preferably from 60 to 99.4% by weight, still
more preferably from 75 to 99% by weight, of the polishing liquid
composition 3-2. The pH of the polishing liquid composition 3-2
having the above composition, which is the same as the polishing
liquid composition 1-2, is preferably 10 or less, more preferably
from 2 to 9.5, still more preferably from 4 to 9, especially
preferably from 7 to 9, from the viewpoints of keeping the
polishing speed at a practical level, suppressing the dishing, and
removing the fine scratch damages on the surface. In order to
adjust the pH within the above ranges, an inorganic acid such as
nitric acid or sulfuric acid, an organic acid, a basic substance
such as potassium hydroxide, sodium hydroxide, ammonia, or an
organic amine can be appropriately added, as occasion demands.
[0105] In addition, when the polishing liquid composition 3 is
prepared from the polishing liquid composition 1-3 (hereinafter
referred to as "polishing liquid composition 3-3"), the amount of
the amine compound and/or salts thereof formulated is preferably
from 0.01 to 30% by weight, more preferably from 0.02 to 10% by
weight, still more preferably from 0.03 to 5% by weight, of the
polishing liquid composition 3-3, from the viewpoints of
maintaining the polishing speed and suppressing the dishing.
[0106] The amount of the etching agent formulated in the polishing
liquid composition 3-3 can be variously selected in order to secure
a polishing speed at a practical level for removal of the metal
layer, and to prevent excessive etching of the metal layer. The
amount formulated is, for instance, preferably from 0.1 to 10% by
weight, more preferably from 0.2 to 8% by weight, still more
preferably from 0.3 to 5% by weight, of the polishing liquid
composition 3-3.
[0107] The amount of the oxidizing agent formulated is preferably
from 0.1 to 60% by weight, more preferably from 0.2 to 50% by
weight, still more preferably from 0.3 to 30% by weight, especially
preferably from 0.3 to 10% by weight, of the polishing liquid
composition 3-3, from the viewpoint of obtaining a polishing speed
at a practical level by rapid oxidation of the metal layer.
[0108] The amount of water formulated is preferably from 39.88 to
99.88% by weight, more preferably from 60 to 99.4% by weight, still
more preferably from 75 to 99% by weight, of the polishing liquid
composition 3-3. The pH of the polishing liquid composition 3-3
having the above composition, which is the same as the polishing
liquid composition 1-3, is preferably 10 or less, more preferably
from 2 to 9.5, still more preferably from 4 to 9, especially
preferably from 5 to 9, from the viewpoints of keeping the
polishing speed at a practical level, suppressing the dishing, and
removing the fine scratch damages on the surface.
[0109] The polishing liquid compositions 1 to 3 of the present
invention can be prepared in any manner without particular
limitations, and for instance, a polishing liquid composition can
be obtained by appropriately mixing each of the above components,
and adjusting a pH. Concrete examples thereof are as follows.
[0110] The polishing liquid composition 1 of the present invention
can be, for instance, prepared by the following procedures. First,
an organic acid and/or an etching agent is added to a given amount
of water, and a pH is adjusted to a given value. To the pH-adjusted
aqueous solution of the organic acid and/or etching agent is added
a given amount of an aqueous solution of a hydroxyl
group-containing compound; or an aqueous solution of an aliphatic
carboxylic acid having 7 to 24 carbon atoms and/or salts thereof,
or an amine compound and/or salts thereof, the aqueous solution of
which pH is adjusted to a given level. A pH is finally adjusted,
whereby a polishing liquid composition 1 can be obtained.
[0111] The polishing liquid composition 2 can be, for instance,
prepared by the following procedures. First, an organic acid and/or
an etching agent is added to a given amount of water, and a pH is
adjusted to a given value. To the pH-adjusted aqueous solution of
the organic acid and/or etching agent is added a given amount of an
aqueous solution of a hydroxyl group-containing compound; or an
aqueous solution of an aliphatic carboxylic acid having 7 to 24
carbon atoms and/or salts thereof, or an amine compound and/or
salts thereof, the aqueous solution of which pH is adjusted to a
given level. An oxidizing agent is added before polishing, and a pH
is finally adjusted, whereby a polishing liquid composition 2 can
be obtained.
[0112] The polishing liquid composition 3 can be, for instance,
prepared by the following procedures. First, an organic acid and/or
an etching agent is added to a given amount of water, and a pH is
adjusted to a given value. To the pH-adjusted aqueous solution of
the organic acid and/or etching agent is added a given amount of an
abrasive, and the mixture is sufficiently stirred so as to
uniformly disperse the abrasives. Further, to the dispersion is
added a given amount of an aqueous solution of a hydroxyl
group-containing compound; or an aqueous solution of an aliphatic
carboxylic acid having 7 to 24 carbon atoms and/or salts thereof,
or an amine compound and/or salts thereof, the aqueous solution of
which pH is adjusted to a given level. A given amount of an
oxidizing agent is added before polishing as occasion demands, and
a pH is finally adjusted, whereby a polishing liquid composition 3
can be obtained.
[0113] In addition, various polishing aids other than those listed
above such as surfactants and dispersion stabilizers may be added
to each of the polishing liquid compositions 1 to 3.
[0114] The polishing liquid composition of the present invention
can be suitably used for the metal CMP in which a surface
comprising an insulating layer and a metal layer is subject to
polishing. The metal constituting the metal layer includes copper
or copper alloys, aluminum or aluminum alloys, tungsten, and the
like. Among these metals, especially when used for a process for
forming embedded metal interconnection on a semiconductor
substrate, copper or copper alloys are preferable. When the
polishing liquid composition of the present invention is used in
the formation of the metal interconnection layer made of copper or
copper alloys, there are exhibited remarkable effects of
maintaining the polishing speed and suppressing the dishing of the
embedded metal interconnection layer. In addition, the material for
forming the insulating layer may be any of organic or inorganic
materials, and includes inorganic materials such as silicon
dioxide, fluorinated silicon dioxide, hydrogen-containing SOG
(spin-on on glass), nitrides, such as tantalum nitride and titanium
nitride; and organic materials such as organic SOG, polyimides,
fluorinated polyimides, methyl polysiloxanes, aromatic polyethers,
hydrogensilsesquioxane, and fluorocarbons.
[0115] The shape of these substrates to be polished is preferably
those having a shape of forming recesses of an interconnection
shape on the insulating film surface of the semiconductor
substrate, and sedimenting metals on the insulating film including
the recesses. In addition, there may be provided a barrier film
made of tantalum, titanium, or a nitride thereof between the
insulating film and the metal layer. Especially when the metal
layer is made of copper or copper alloys, it is preferable to
provide the barrier film, whereby the diffusion of the copper to
the insulating layer can be prevented.
[0116] The polishing liquid compositions 1 and 2 of the present
invention are effective for a polishing processes using a fixed
grinding wheel, a polishing pad in which abrasive grains are fixed
to the pad, and the like. The polishing liquid composition 3 is
effective for a polishing process by loose abrasives using a usual
polishing pad made of urethane, and it is also effective for a
polishing processes using a fixed grinding wheel, a polishing pad
in which abrasive grains are fixed to the pad, and the like.
[0117] The process for polishing a surface to be polished
comprising an insulating layer and a metal layer of the present
invention comprises polishing a semiconductor substrate using the
polishing liquid composition of the present invention, thereby
smoothening the polished surface.
[0118] In addition, the process for manufacturing a semiconductor
substrate of the present invention comprises polishing a
semiconductor surface comprising an insulating layer and a metal
layer using the polishing liquid composition of the present
invention, whereby the polishing speed of the metal layer can be
maintained and the dishing of the embedded metal interconnection
layer can be suppressed. Therefore, the process can be suitably
applied to a process for manufacturing the semiconductor
substrate.
EXAMPLES I-1 to I-14 AND COMPARATIVE EXAMPLES I-1 TO I-4
[0119] Compounds having a structure in which each of two or more
adjacent carbon atoms has hydroxyl group in a molecule (hydroxyl
group-containing compound) used in Examples I-1 to I-14 are shown
in Table 1. The hydroxyl group-containing compound shown in Table
1, the organic acid shown in Table 2, and hydrogen peroxide were
mixed so as to have the proportion shown in Table 2. Further, 5% by
weight portion of an abrasive shown in Table 2 and balance water
were mixed with stirring, and thereafter a pH of the liquid mixture
was adjusted to 4.0, to give a polishing liquid composition.
Incidentally, each of the used abrasives was fumed silica (primary
particle size: 50 nm) and colloidal silica (primary particle size:
30 nm). In addition, each of the hydroxyl group-containing
compounds "a" to "e" of Table 1 dissolves in water at 1.0% by
weight or more. The substrate to be polished was polished under the
following conditions by single-sided polishing machine.
Hereinbelow, the terms inside quotation marks are trade names.
Setting Conditions of Single-Sided Processing Machine
[0120] Single-sided processing machine used: single-sided polishing
machine (disc size: 30 cm), manufactured by Engis. [0121]
Processing pressure: 29.4.times.10.sup.3 Pa [0122] Polishing Pad:
upper layer: "IC1000" (manufactured by Rodel Nitta K.K.); and lower
layer: "SUBA400" (manufactured by Rodel Nitta K.K.). [0123] Disc
rotational speed: 60 rpm [0124] Work rotational speed: 50 rpm
(rotating disc and work in the same direction) [0125] Feeding flow
rate for a polishing liquid composition: 100 ml/min [0126]
Polishing time period: 10 minutes
[0127] In addition, the properties of the polishing liquid
composition such as relative polishing speed, relative etching
speed, and dishing of the surface to be polished were evaluated in
accordance with the following methods. The results thereof are
shown in Table 2.
Relative Polishing Speed
[0128] The relative polishing speed is a value obtained by dividing
the polishing speed of a polishing liquid composition by a
polishing speed of a comparative example where the kinds and the
amounts of an abrasive, an oxidizing agent and an etching agent
were the same as the polishing liquid composition. The polishing
speed was obtained by polishing a rolled copper plate of a diameter
of 50 mm and a plate thickness of 1 mm, determining a change in the
thickness before and after polishing, and dividing the resultant
value by a polishing time. Incidentally, the thickness of the
copper plate was measured by using a high-precision digital
analyzer "MINIAX" commercially available from K. K. Tokyo Seimitsu.
Here, each of the relative polishing speeds for Examples I-1 to I-5
and I-9 to I-10 was calculated based on Comparative Example I-1;
each of the relative polishing speeds for Examples I-6 to I-8 was
calculated based on Comparative Example I-2; and each of the
relative polishing speeds for Examples I-13 to I-14 was calculated
based on Comparative Example I-3. Incidentally, apart from the
above, the relative polishing speed for Examples I-11 was
calculated based on Comparative Example I-1; the relative polishing
speed for Examples I-12 was calculated based on Comparative Example
I-2; and the relative polishing speed for Comparative Example I-4
was calculated based on Comparative Example I-1.
Relative Etching Speed
[0129] The relative etching speed is a value obtained by dividing
an etching speed of the polishing liquid composition comprising the
above hydroxyl group-containing compound by an etching speed "b" of
a polishing liquid composition not containing the above hydroxyl
group-containing compound but having the same kinds and the amounts
of an abrasive, an oxidizing agent and an etching agent as the
polishing liquid composition. Here, each of the relative etching
speeds for Examples I-1 to I-5 and I-9 to I-10 was calculated based
on Comparative Example I-1; each of the relative etching speeds for
Examples I-6 to I-8 was calculated based on Comparative Example
I-2; and each of the relative etching speeds for Examples I-13 to
I-14 was calculated based on Comparative Example I-3. Incidentally,
apart from the above, the relative etching speed for Examples I-11
was calculated based on Comparative Example I-1; the relative
etching speed for Examples I-12 was calculated based on Comparative
Example I-2; and the relative etching speed for Comparative Example
I-4 was calculated based on Comparative Example I-1. Incidentally,
each the etching speeds for each the polishing liquid compositions
of Examples 1-1 to I-14 and Comparative Example I-4 was a value
measured under the same conditions as the above etching test B
described above, except for using these polishing liquid
compositions.
Dishing
[0130] In order to evaluate dishing, a wafer chip of a square with
a side of 20 mm was cut out from a wafer (commercially available
from SKW, "SKW6-2", size: 200 mm) with copper damascene
interconnection patterns. Five wafer chips were fixed on an
adhesive plate made of ceramic. Thereafter, a copper film in the
periphery of the copper interconnection portion, the
interconnection of which had a width of 150 .mu.m, was removed,
with confirming the state under the above conditions. The substrate
was polished to a point where a barrier film appeared, and was
further polished with 20% of a time period required for polishing
until this point, to provide a sample for evaluating dishing. The
dishing was evaluated by determining a cross section profile of a
copper interconnection portion, the interconnection of which had a
width of 150 .mu.m by a surface roughness tester (commercially
available from (K.K) Mitsutoyo, "SV-600"). Incidentally, when there
were no recesses having sizes of 0.15 .mu.m or more in the cross
section profile of the copper interconnection tested, it was
evaluated as absence of dishing, and when there were recesses
having sizes of 0.15 .mu.m or more, it was evaluated as presence of
dishing, which are respectively denoted in Table 2 as "absence" or
"presence."
[0131] Here, the etching speed "b" of the polishing liquid
compositions used for Comparative Examples I-1 to I-3 were as
follows. [0132] Comparative Example I-1: 80 .ANG./min [0133]
Comparative Example I-2: 80 .ANG./min
[0134] Comparative Example I-3: 200 .ANG./min TABLE-US-00001 TABLE
1 No. Hydroxyl Group-Containing Compound a
n-C.sub.4H.sub.9CH(OH)CH.sub.2OH b
n-C.sub.4H.sub.9OCH.sub.2CH(OH)CH.sub.2OH c
n-C.sub.6H.sub.13COOCH.sub.2CH(OH)CH.sub.2OH d
(n-C.sub.3H.sub.7).sub.2NCH.sub.2CH(OH)CH.sub.2OH e
n-C.sub.3H.sub.7OCOCH(OH)CH(OH)COO-n-C.sub.3H.sub.7
[0135] TABLE-US-00002 TABLE 2 Hydroxyl Group- Hydrogen Containing
Compound Organic Acid Peroxide Content Content Content Abrasive
Kind (% by wt.) Kind (% by wt.) (% by wt.) Kind Ex. No. I-1 a 1.0
Gluconic 2.0 2.0 Fumed acid Silica I-2 b 1.0 Gluconic 2.0 2.0 Fumed
acid Silica I-3 c 1.0 Gluconic 2.0 2.0 Fumed acid Silica I-4 d 1.0
Gluconic 2.0 2.0 Fumed acid Silica I-5 e 1.0 Gluconic 2.0 2.0 Fumed
acid Silica I-6 a 1.0 Gluconic 2.0 2.0 Colloidal acid Silica I-7 b
1.0 Gluconic 2.0 2.0 Colloidal acid Silica I-8 c 1.0 Gluconic 2.0
2.0 Colloidal acid Silica I-9 a 0.5 Gluconic 2.0 2.0 Fumed acid
Silica I-10 a 2.0 Gluconic 2.0 2.0 Fumed acid Silica I-11 b 1.0 --
-- 2.0 Fumed Silica I-12 b 1.0 Gluconic 2.0 -- Colloidal acid
Silica I-13 a 1.0 Glycolic 2.0 2.0 Colloidal acid Silica I-14 b 1.0
Glycolic 2.0 2.0 Colloidal acid Silica Comp. Ex. No. I-1 -- --
Gluconic 2.0 2.0 Fumed acid Silica I-2 -- -- Gluconic 2.0 2.0
Colloidal acid Silica I-3 -- -- Glycolic 2.0 2.0 Colloidal acid
Silica I-4 Benzotriazole 1.0 Gluconic 2.0 2.0 Fumed acid Silica
Evaluation of Properties Relative Polishing Relative Etching Speed
Speed Based on Based on Based on Based on Based on Based on C. Ex.
I-1 C. Ex. I-2 C. Ex. I-3 C. Ex. I-1 C. Ex. I-2 C. Ex. I-3 Dishing
Ex. No. I-1 1.0 -- -- 0.1 or -- -- Absence less I-2 1.0 -- -- 0.1
or -- -- Absence less I-3 1.0 -- -- 0.15 -- -- Absence I-4 1.1 --
-- 0.15 -- -- Absence I-5 1.1 -- -- 0.2 -- -- Absence I-6 -- 1.0 --
-- 0.1 or -- Absence less I-7 -- 1.0 -- -- 0.1 or -- Absence less
I-8 -- 1.1 -- -- 0.15 -- Absence I-9 1.1 -- -- 0.1 or -- -- Absence
less I-10 1.0 -- -- 0.1 or -- -- Absence less I-11 0.7 -- -- 0.1 or
-- -- Absence less I-12 -- 0.7 -- -- 0.1 or -- Absence less I-13 --
-- 0.9 -- -- 0.1 Absence or less I-14 -- -- 0.9 -- -- 0.1 Absence
or less Comp. Ex. No. I-1 1.0 -- -- 1.0 -- -- Presence I-2 -- 1.0
-- -- 1.0 -- Presence I-3 -- -- 1.0 -- -- 1.0 Presence I-4 0.1 --
-- 0.1 or -- -- * less Note *The polishing speed was too slow to be
evaluated.
[0136] It is found from the results of Tables 1 and 2 that all of
the polishing liquid compositions of Examples I-1 to I-14 where the
hydroxyl group-containing compound is formulated in the polishing
liquid composition suppressed the etching speed and the dishing is
not generated without substantially lowering the polishing speed,
as compared to the polishing liquid compositions of Comparative
Examples I-1 to I-3 where the hydroxyl group-containing compound is
not formulated.
[0137] In addition, it is found that the polishing liquid
composition of Comparative Example I-4 where benzotriazole acting
to suppressing etching was used in place of the hydroxyl
group-containing compound, the polishing speed is extremely
low.
[0138] Also, it is found that by using the hydroxyl
group-containing compound, the etching agent, and the oxidizing
agent, a higher polishing speed can be realized, and the dishing
can be prevented.
EXAMPLES II-1 TO II-12 AND COMPARATIVE EXAMPLES II-1 TO II-12
[0139] Each of the etching agents shown in Tables 3 and 4, and
hydrogen peroxide were mixed with a given amount of water, so as to
have the proportion shown in Tables 3 and 4. Further, 5% by weight
portion of the abrasive shown in Tables 3 and 4 were mixed with
stirring, and thereafter an aqueous ammonia was added so as to have
a pH of the liquid mixture of 7.5 to 8. Separately from above, an
aqueous ammonia was previously added to an aliphatic carboxylic
acid having 7 to 24 carbon atoms to adjust the pH to 7.5 to 8,
whereby preparing an aqueous solution of the aliphatic carboxylic
acid or its salt. The aqueous solution of the aliphatic carboxylic
acid or its salt was mixed with the above liquid mixture with
stirring, so as to have the proportion shown in Tables 3 and 4.
Thereafter, a pH of the liquid mixture was adjusted to a value
shown in Tables 3 and 4, to give each polishing liquid composition.
Incidentally, each of the used abrasives was fumed silica (primary
particle size: 50 nm) and colloidal silica (primary particle size:
100 nm). In addition, a rolled copper plate of a diameter of 50 mm
and a plate thickness of 1 mm was polished under the same
conditions as above by single-sided polishing machine.
[0140] In addition, the properties of the polishing liquid
composition such as relative polishing speed, relative etching
speed, dishing of the surface to be polished, and surface condition
of copper were evaluated in accordance with the following methods.
The results thereof are shown in Tables 3 and 4.
Relative Polishing Speed
[0141] The relative polishing speed is a value obtained by dividing
the polishing speed of a polishing liquid composition by a
polishing speed of a comparative example where the kinds and the
amounts of an abrasive, an oxidizing agent and an etching agent
were the same as the polishing liquid composition. The polishing
speed was obtained by polishing a rolled copper plate of a diameter
of 50 mm and a plate thickness of 1 mm under the polishing
conditions mentioned above, determining a change in the thickness
before and after polishing, and dividing the resultant value by a
polishing time. Incidentally, the thickness of the copper plate was
measured by using a high-precision digital analyzer "MINIAX"
commercially available from K. K. Tokyo Seimitsu. Here, each of the
relative polishing speeds for Examples II-1 to II-6 was calculated
based on Comparative Example II-1; the relative polishing speed for
Example II-7 was calculated based on Comparative Example II-2; the
relative polishing speed for Example II-8 was calculated based on
Comparative Example II-3; the relative polishing speed for Example
II-9 was calculated based on Comparative Example II-4; the relative
polishing speed for Example II-10 was calculated based on
Comparative Example II-5; the relative polishing speed for Example
II-11 was calculated based on Comparative Example II-11; the
relative polishing speed for Example II-12 was calculated based on
Comparative Example II-12; the relative polishing speed for
Comparative Example II-9 was calculated based on Comparative
Example II-1; and the relative polishing speed for Comparative
Example II-10 was calculated based on Comparative Example II-2.
Incidentally, apart from the above, each of the relative polishing
speeds for Comparative Examples II-6 to II-8 was calculated based
on Comparative Example II-1.
Relative Etching Speed
[0142] The relative etching speed is a value obtained by dividing
an etching speed of the polishing liquid composition comprising the
above aliphatic carboxylic acid and/or its salt by an etching speed
"c" of a polishing liquid composition not containing the above
aliphatic carboxylic acid and/or its salt but having the same kinds
and the amounts of an abrasive, an oxidizing agent and an etching
agent as the polishing liquid composition. Here, each of the
relative etching speeds for Examples II-1 to II-6 was calculated
based on Comparative Example II-1; the relative etching speed for
Example II-7 was calculated based on Comparative Example II-2; the
relative etching speed for Example II-8 was calculated based on
Comparative Example II-3; the relative etching speed for Example
II-9 was calculated based on Comparative Example II-4; the relative
etching speed for Example II-10 was calculated based on Comparative
Example II-5; the relative etching speed for Example II-11 was
calculated based on Comparative Example II-11; the relative etching
speed for Example II-12 was calculated based on Comparative Example
II-12; the relative etching speed for Comparative Example II-9 was
calculated based on Comparative Example II-1; and the relative
etching speed for Comparative Example II-10 was calculated based on
Comparative Example II-2. Incidentally, apart from the above, each
of the relative etching speeds for Comparative Examples II-6 to
II-8 was calculated based on Comparative Example II-1.
Incidentally, each the etching speeds for each the polishing liquid
compositions of Examples II-1 to II-12 and Comparative Examples
II-7 to II-8 was a value measured under the same conditions as the
above etching test C described above, except for using these
polishing liquid compositions.
Dishing
[0143] Dishing was evaluated in the same manner as above.
Incidentally, when there were no recesses having sizes of 0.15
.mu.m or more in the cross section profile of the copper
interconnection tested, it was evaluated as absence of dishing, and
when there were recesses having sizes of 0.15 .mu.m or more, it was
evaluated as presence of dishing, which are respectively denoted in
Tables 3 and 4 as "absence" or "presence."
Copper Surface Condition
[0144] The surface condition of the copper film at the copper
interconnection portion, the interconnection of which has a width
of 150 .mu.m on the surface of wafer chip used in the evaluation of
the dishing was observed by optical microscope, to confirm the
presence or absence of roughening.
[0145] Here, the etching speed "c" of the polishing liquid
compositions used for Comparative Examples II-1 to II-6 were as
follows. [0146] Comparative Example II-1: 50 .ANG./min [0147]
Comparative Example II-2: 100 .ANG./min [0148] Comparative Example
II-3: 200 .ANG./min [0149] Comparative Example II-4: 600 .ANG./min
[0150] Comparative Example II-5: 50 .ANG./min
[0151] Comparative Example II-6: 100 .ANG./min TABLE-US-00003 TABLE
3 Aliphatic Carboxylic Acid Hydrogen and/or Its Salt Etching Agent
Peroxide Abrasive Ex. No. Kind Content Kind Content Content Kind pH
II-1 Octanoic acid 0.6.sup.1) Glycolic acid 2.0.sup.1) 4.0.sup.1)
Colloidal 7.6 Silica II-2 Nonanoic 0.3 Glycolic acid 2.0 4.0
Colloidal 7.7 acid Silica II-3 Heptanoic 1.2 Glycolic acid 2.0 4.0
Colloidal 7.6 acid Silica II-4 Decanoic 0.3 Glycolic acid 2.0 4.0
Colloidal 7.7 acid Silica II-5 Oleic acid 0.3 Glycolic acid 2.0 4.0
Colloidal 8.0 Silica II-6 Isooctanoic 1.5 Glycolic acid 2.0 4.0
Colloidal 7.7 acid.sup.2) Silica II-7 Octanoic 1.2 Citric acid 2.0
2.0 Fumed 7.6 acid Silica II-8 Octanoic 1.0 Phthalic 2.0 2.0 Fumed
7.9 acid acid Silica II-9 Octanoic 1.5 Aminotri- 2.0 2.0 Fumed 7.6
acid (methylene- Silica phosphonic acid) II-10 Octanoic 0.4
Glycolic acid 2.0 -- Colloidal 7.6 acid Silica II-11 Octanoic 1.0
Hydrochloric 2.0 2.0 Colloidal 7.7 acid acid Silica II-12 Octanoic
0.5 Sulfuric acid 2.0 2.0 Colloidal 7.9 acid Silica Evaluation for
Properties Relative Relative Comp. Ex. To Copper Polishing Etching
Which Evaluation Surface Ex. No. Speed Speed Was Based Dishing
Condition II-1 1.0 0.1 or less Comp. Ex. II-1 Absence No Roughening
II-2 1.0 0.1 or less Comp. Ex. II-1 Absence No Roughening II-3 1.0
0.1 or less Comp. Ex. II-1 Absence No Roughening II-4 0.9 0.1 or
less Comp. Ex. II-1 Absence No Roughening II-5 0.9 0.1 or less
Comp. Ex. II-1 Absence No Roughening II-6 1.0 0.1 or less Comp. Ex.
II-1 Absence No Roughening II-7 1.0 0.1 or less Comp. Ex. II-2
Absence No Roughening II-8 0.9 0.1 or less Comp. Ex. II-3 Absence
No Roughening II-9 0.9 0.1 or less Comp. Ex. II-4 Absence No
Roughening II-10 0.9 0.1 or less Comp. Ex. II-5 Absence No
Roughening II-11 0.9 0.1 or less Comp. Ex. II-11 Absence No
Roughening II-12 0.9 0.1 or less Comp. Ex. II-12 Absence No
Roughening Note .sup.1)% by weight .sup.2)Secanoic C8 acid (trade
name, commercially available from Exon Chemicals K.K.)
[0152] TABLE-US-00004 TABLE 4 Aliphatic Carboxylic Acid Hydrogen
Comp. and/or Its Salt Etching Agent Peroxide Abrasive Ex. No. Kind
Content Kind Content Content Kind pH II-1 -- -- Glycolic acid
2.0.sup.1) 4.0.sup.1) Colloidal 7.6 Silica II-2 -- -- Citric acid
2.0 2.0 Fumed 7.6 Silica II-3 -- -- Phthalic 2.0 2.0 Fumed 7.9 acid
Silica II-4 -- -- Aminotri- 2.0 2.0 Fumed 7.6 (methylene- Silica
phosphonic acid) II-5 -- -- Glycolic acid 2.0 -- Colloidal 7.6
Silica II-6 -- -- Glycolic acid 1.0 4.0 Colloidal 7.6 Citric acid
1.0 Silica II-7 Octanoic 0.5.sup.1) -- -- 4.0 Colloidal 7.8 acid
Silica Heptanoic 0.5 acid II-8 Oleic acid 0.5 -- -- 4.0 Colloidal
7.6 Silica II-9 Benzotriazole 0.3 Glycolic acid 2.0 4.0 Colloidal
7.6 Silica II-10 Ammonium 1.0 Citric acid 2.0 2.0 Fumed 7.6
Polyacrylate Silica II-11 -- -- Hydrochloric 2.0 2.0 Colloidal 7.7
acid Silica II-12 -- -- Sulfuric 2.0 2.0 Colloidal 7.9 acid Silica
Evaluation for Properties Relative Relative Comp. Ex. To Copper
Comp. Polishing Etching Which Evaluation Surface Ex. No. Speed
Speed Was Based Dishing Condition II-1 1.0 1.0 -- Presence No
Roughening II-2 1.0 1.0 -- Presence No Roughening II-3 1.0 1.0 --
Presence No Roughening II-4 1.0 1.0 -- Presence No Roughening II-5
1.0 1.0 -- Presence No. Roughening II-6 1.3 1.5 Comp. Ex. II-1
Presence No Roughening II-7 0.1 or less 0.1 or less Comp. Ex. II-1
The polishing speed was too slow to be evaluated. II-8 0.1 or less
0.1 or less Comp. Ex. II-1 II-9 0.1 or less 0.1 or less Comp. Ex.
II-1 II-10 1.2 0.1 or less Comp. Ex. II-2 Absence Presence of
Roughening II-11 1.0 1.0 -- Presence No Roughening II-12 1.0 1.0 --
Presence No Roughening Note .sup.1)% by weight
[0153] It is found from the results of Tables 3 and 4 that all of
the polishing liquid compositions of Examples II-1 to II-12 where
the aliphatic carboxylic acid having 7 to 24 carbon atoms is
formulated in the polishing liquid composition suppressed the
etching speed and the dishing is not generated without
substantially lowering the polishing speed, as compared to the
polishing liquid compositions of Comparative Examples II-1 to II-5,
II-11 and II-12 where the aliphatic carboxylic acid is not
formulated.
[0154] In addition, the polishing liquid composition of Comparative
Example II-6 where two kinds of aliphatic carboxylic acids having 6
or less carbon atoms are used in combination without using the
aliphatic carboxylic acid having 7 to 24 carbon atoms has high
etching speed and the dishing generated.
[0155] In addition, it is found that all of the polishing liquid
composition of Comparative Example II-7 where two kinds of the
aliphatic carboxylic acids having 7 to 24 carbon atoms are used in
combination; the polishing liquid composition of Comparative
Example II-8 where the organic acid capable of forming an aqueous
salt with copper is not formulated; and the polishing liquid
composition of Comparative Example II-9 where benzotriazole for
suppressing etching is formulated have extremely low polishing
speeds, and that the polishing liquid composition of Comparative
Example II-10 where ammonium polyacrylate is formulated has copper
surface with roughening generated.
[0156] Therefore, an even higher polishing speed can be realized by
using the aliphatic carboxylic acid having 7 to 24 carbon atoms in
combination with an etching agent, and the dishing can be
prevented.
[0157] Especially, from the viewpoint of keeping the
low-foamability during polishing, it is more preferable that the
aliphatic carboxylic add having 7 to 24 carbon atoms is heptanoic
acid, octanoic acid and nonanoic acid.
EXAMPLES III-1 TO III-8 AND COMPARATIVE EXAMPLES III-1 TO III-5
[0158] Each of the etching agents shown in Table 5, and the amine
compound were mixed with a given amount of water, so as to have the
proportion shown in Table 5, and thereafter an aqueous ammonia was
added so as to have a pH of the liquid mixture of 6 to 8. Further,
hydrogen peroxide was added so as to have a proportion shown in
Table 5. Further, 5% by weight portion of an abrasive shown in
Table 5 was mixed with stirring, and thereafter a pH of the liquid
mixture was adjusted to the value shown in Table 5, to give a
polishing liquid composition. Incidentally, each of the used
abrasives was fumed silica (primary particle size: 50 nm) and
colloidal silica (primary particle size: 100 nm). In addition, a
rolled copper plate of a diameter of 50 mm and a plate thickness of
1 mm was polished under the same conditions as above by
single-sided polishing machine.
[0159] In addition, the properties of the polishing liquid
composition such as relative polishing speed, relative etching
speed, and dishing of the surface to be polished were evaluated in
accordance with the following methods. The results thereof are
shown in Table 5.
Relative Polishing Speed
[0160] The relative polishing speed is a value obtained by dividing
the polishing speed of a polishing liquid composition by a
polishing speed of a comparative example where the kinds and the
amounts of an abrasive, an oxidizing agent and an etching agent
were the same as the polishing liquid composition. The polishing
speed was obtained by polishing a rolled copper plate of a diameter
of 50 mm and a plate thickness of 1 mm, determining a change in the
thickness before and after polishing, and dividing the resultant
value by a polishing time. Incidentally, the thickness of the
copper plate was measured by using a high-precision digital
analyzer "MINIAX" commercially available from K. K. Tokyo Seimitsu.
Here, each of the relative polishing speeds for Examples III-1,
III-2, III-4, III-5, and III-7 was calculated based on Comparative
Example III-1; the relative polishing speed for Example III-6 was
calculated based on Comparative Example III-2; the relative
polishing speed for Example III-3 was calculated based on
Comparative Example III-3; and the relative polishing speed for
Example III-8 was calculated based on Comparative Example III-4.
Incidentally, apart from the above, the relative polishing speed
for Comparative Example III-5 was calculated based on Comparative
Example III-1.
Relative Etching Speed
[0161] The relative etching speed is a value obtained by dividing
an etching speed of the polishing liquid composition comprising the
above amine compound and/or its salt by an etching speed "c" of a
polishing liquid composition not containing the above amine
compound and/or its salt but having the same kinds and the amounts
of an abrasive, an oxidizing agent and an etching agent as the
polishing liquid composition. Here, each of the relative etching
speeds for Examples III-1, III-2, III-4, III-5, and III-7 was
calculated based on Comparative Example III-1; the relative etching
speed for Example III-6 was calculated based on Comparative Example
III-2; the relative etching speed for Example III-3 was calculated
based on Comparative Example III-3; and the relative etching speed
for Example III-8 was calculated based on Comparative Example
III-4. Incidentally, apart from the above, the relative etching
speed for Comparative Example III-5 was calculated based on
Comparative Example III-1. Incidentally, each the etching speeds
for each the polishing liquid compositions of Examples III-1 to
III-8 and Comparative Example III-5 was a value measured under the
same conditions as the above etching test C described above, except
for using these polishing liquid compositions.
Dishing
[0162] Dishing was evaluated in the same manner as above.
Incidentally, when there were no recesses having sizes of 0.15
.mu.m or more in the cross section profile of the copper
interconnection tested, it was evaluated as absence of dishing, and
when there were recesses having sizes of 0.15 .mu.m or more, it was
evaluated as presence of dishing, which are respectively denoted in
Table 5 as "absence" or "presence."
[0163] Here, the etching speed "c" of the polishing liquid
compositions used for Comparative Examples III-1 to III-4 were as
follows. [0164] Comparative Example III-1: 50 .ANG./min [0165]
Comparative Example III-2: 100 .OR right./min [0166] Comparative
Example III-3: 50 .ANG./min
[0167] Comparative Example III-4: 50 .ANG./min TABLE-US-00005 TABLE
5 Hydrogen Amine Compound Etching Agent Peroxide Content Content
Content Abrasive Kind (% by wt.) Kind (% by wt.) (% by wt.) Kind pH
Ex. No. III-1 Octylamine 0.8 Glycolic 2.0 4.0 Colloidal 7.6 acid
Silica III-2 Nonylamine 0.5 Glycolic 2.0 4.0 Colloidal 7.6 acid
Silica III-3 Decylamine 1.0 Hydrochloric 2.0 2.0 Colloidal 7.7 acid
Silica III-4 Oleylamine 0.4 Glycolic 2.0 4.0 Colloidal 7.6 acid
Silica III-5 Dimethyl- 0.5 Glycolic 2.0 4.0 Colloidal 7.6
dodecylamine acid Silica III-6 Dimethyl- 0.8 Citric 2.0 2.0 Fumed
7.6 dodecylamine acid Silica III-7 Dodecyl- 0.8 Glycolic 2.0 4.0
Colloidal 7.6 diethanolamine acid Silica III-8 Octylamine 0.5
Glycolic 2.0 -- Colloidal 7.6 acid Silica Comp. Ex. No. III-1 -- --
Glycolic 2.0 4.0 Colloidal 7.6 acid Silica III-2 -- -- Citric 2.0
2.0 Fumed 7.6 acid Silica III-3 -- -- Hydrochloric 2.0 2.0
Colloidal 7.7 acid Silica III-4 -- -- Glycolic 2.0 -- Colloidal 7.6
acid Silica III-5 Benzotriazole 0.3 Glycolic 2.0 4.0 Colloidal 7.6
acid Silica Evaluation for Properties Relative Relative Comp. Ex.
To Polishing Etching Which Evaluation Speed Speed Was Based Dishing
Ex. No. III-1 1.0 0.1 or less Comp. Ex. III-1 Absence III-2 0.9 0.1
or less Comp. Ex. III-1 Absence III-3 1.0 0.1 or less Comp. Ex.
III-3 Absence III-4 0.9 0.1 or less Comp. Ex. III-1 Absence III-5
0.9 0.1 or less Comp. Ex. III-1 Absence III-6 0.9 0.1 or less Comp.
Ex. III-2 Absence III-7 0.9 0.1 or less Comp. Ex. III-1 Absence
III-8 0.9 0.1 or less Comp. Ex. III-4 Absence Comp. Ex. No. III-1
1.0 1.0 -- Presence III-2 1.0 1.0 -- Presence III-3 1.0 1.0 --
Presence III-4 1.0 1.0 -- Presence III-5 0 1 or less 0.1 or less
Comp. Ex. III-1 * Note *The polishing speed was too slow to be
evaluated.
[0168] It is found from the results of Table 5 that all of the
polishing liquid compositions of Examples III-1 to III-8 where the
amine compound is formulated in the polishing liquid composition
suppressed the etching speed and the dishing is not generated
without substantially lowering the polishing speed, as compared to
the polishing liquid compositions of Comparative Examples III-1 to
III-4 where the amine compound is not formulated.
[0169] In addition, it is found that the polishing liquid
composition of Comparative Example III-5 where benzotriazole acting
to suppressing etching was used in place of the amine compound, the
polishing speed is extremely low.
[0170] Therefore, it is found that an even higher polishing speed
can be realized by using the amine compound in combination with an
etching agent, and the dishing can be prevented.
[0171] Especially, from the viewpoint of keeping the
low-foamability during polishing, it is more preferable that the
amine compound is heptylamine, octylamine and nonylamine.
[0172] Since the polishing liquid composition of the present
invention is used for polishing a surface to be polished comprising
an insulating layer and a metal layer, there are exhibited such
effects that the polishing speed of the metal film is maintained,
that the etching speed is suppressed, and defects such as dishing
in the interconnection metal layer is not generated.
* * * * *