U.S. patent application number 10/980271 was filed with the patent office on 2005-06-16 for chemical mechanical polishing slurries and cleaners containing salicylic acid as a corrosion inhibitor.
Invention is credited to Carter, Melvin K., Scott, Brandon Shane.
Application Number | 20050126588 10/980271 |
Document ID | / |
Family ID | 34657051 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050126588 |
Kind Code |
A1 |
Carter, Melvin K. ; et
al. |
June 16, 2005 |
Chemical mechanical polishing slurries and cleaners containing
salicylic acid as a corrosion inhibitor
Abstract
The invention provides methods for CMP polishing, residue
removal and post-CMP polishing of a metal containing substrate. The
CMP polishing methods for contacting a metal-containing substrate
with a composition comprising an oxider, a salicylic acid compound,
water, and an abrasive. The post-CMP polishing and residue removal
methods require contacting a metal-containing substrate with a
composition comprising an oxidizer, a salicylic acid compound, and
water.
Inventors: |
Carter, Melvin K.; (Los
Gatos, CA) ; Scott, Brandon Shane; (Hayward,
CA) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Family ID: |
34657051 |
Appl. No.: |
10/980271 |
Filed: |
November 4, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60516736 |
Nov 4, 2003 |
|
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|
Current U.S.
Class: |
134/3 ; 134/2;
134/41; 257/E21.304 |
Current CPC
Class: |
C11D 7/265 20130101;
C11D 7/3218 20130101; C11D 11/0029 20130101; C23G 1/06 20130101;
H01L 21/02074 20130101; H01L 21/3212 20130101; C23G 1/106 20130101;
C23G 1/103 20130101; C23F 3/06 20130101; C11D 11/0047 20130101 |
Class at
Publication: |
134/003 ;
134/002; 134/041 |
International
Class: |
C23G 001/00 |
Claims
1-19. (canceled)
20. A method of cleaning a metal-containing substrate that had
previously undergone a chemical mechanical polishing process
comprising the steps of: contacting the chemically mechanically
polished metal-containing substrate with a composition comprising:
an oxidizer; a salicylic acid compound having the formula: 2where
R.sub.1 and R.sub.2 are independently hydrogen, an organic
salt/counterion, an inorganic salt/counterion, a C.sub.1-C.sub.20
linear or branched, saturated or unsaturated, optionally singly or
multiply substituted alkyl moiety, a C.sub.5-C.sub.20 optionally
singly or multiply substituted aryl or heteroaryl moiety, or a
combination thereof, and where R.sub.3 is a hydrogen, a
C.sub.1-C.sub.20 linear or branched, saturated or unsaturated,
optionally singly or multiply substituted alkyl moiety, a
C.sub.5-C.sub.20 optionally singly or multiply substituted aryl or
heteroaryl moiety, or a combination thereof, and wherein optionally
substituted moieties comprise hydroxyls, nitro groups, sulfates,
phosphates, amines, amides, carboxylic acids, carboxylate salts,
carboxylate esters, halides, alkyl or aryl ethers, C.sub.1-C.sub.6
linear or branched, saturated or unsaturated alkyl groups,
C.sub.5-C.sub.12 aryl groups, or the like, or a combination or
reaction product thereof; and water, wherein the contacting occurs
at a temperature and for a time sufficient to clean the
metal-containing substrate.
21. The method of claim 20, wherein the oxidizer comprises
hydroxylamine or a hydroxylamine derivative having the formula:
3wherein R.sub.1 is hydrogen or a linear, branched, or cyclic
hydrocarbon containing from 1 to 7 carbon atoms, and wherein X and
Y are, independently, hydrogen or a linear, branched, or cyclic
hydrocarbon containing from 1 to 7 carbon atoms, or wherein X and Y
are linked together form a nitrogen-containing heterocyclic 4- to
7-membered ring.
22-23. (canceled)
24. The method of claim 20, wherein the salicylic acid compound
comprises salicylic acid.
25. The method of claim 20, wherein the oxidizer is hydrogen
peroxide.
26. The method of claim 20, wherein the oxidizer is periodic
acid.
27. The method of claim 20, wherein the oxidizer comprises
persulfide.
28. A method of post-etch residue removal for a metal-containing
substrate comprising the steps of: contacting a metal-containing
substrate that has previously been etched with a composition
comprising: an oxidizer; a salicylic acid compound having the
formula: 4where R.sub.1 and R.sub.2 are independently hydrogen, an
organic salt/counterion, an inorganic salt/counterion, a
C.sub.1-C.sub.20 linear or branched, saturated or unsaturated,
optionally singly or multiply substituted alkyl moiety, a
C.sub.5-C.sub.20 optionally singly or multiply substituted aryl or
heteroaryl moiety, or a combination thereof, and where R.sub.3 is a
hydrogen, a C.sub.1-C.sub.20 linear or branched, saturated or
unsaturated, optionally singly or multiply substituted alkyl
moiety, a C.sub.5-C.sub.20 optionally singly or multiply
substituted aryl or heteroaryl moiety, or a combination thereof,
and wherein optionally substituted moieties comprise hydroxyls,
nitro groups, sulfates, phosphates, amines, amides, carboxylic
acids, carboxylate salts, carboxylate esters, halides, alkyl or
aryl ethers, C.sub.1-C.sub.6 linear or branched, saturated or
unsaturated alkyl groups, C.sub.5-C.sub.12 aryl groups, or the
like, or a combination or reaction product thereof; and water,
wherein the contacting occurs at a temperature and for a time
sufficient to remove post-etch residue from the metal-containing
substrate.
29. A method for cleaning and/or removing residue from a
metal-containing substrate that has previously been
chemically-mechanically polished, etched, or both, the method
comprising: contacting the previously treated metal-containing
substrate with a composition that comprises from about 0.00001M to
about 0.5M of a salicylic acid compound having the formula: 5where
R.sub.1 and R.sub.2 are each independently hydrogen; an organic
salt/counterion; an inorganic salt/counterion; a C.sub.1-C.sub.20
linear or branched, saturated or unsaturated, optionally singly or
multiply substituted alkyl moiety; a C.sub.5-C.sub.20 optionally
singly or multiply substituted aryl or heteroaryl moiety; or a
combination thereof, and where R.sub.3 is hydrogen; a
C.sub.1-C.sub.20 linear or branched, saturated or unsaturated,
optionally singly or multiply substituted alkyl moiety; a
C.sub.5-C.sub.20 optionally singly or multiply substituted aryl or
heteroaryl moiety; or a combination thereof, wherein optionally
substituted moieties comprise hydroxyls, nitro groups, sulfates,
phosphates, amines, amides, carboxylic acids, carboxylate salts,
carboxylate esters, halides, alkyl or aryl ethers, C.sub.1-C.sub.6
linear or branched, saturated or unsaturated alkyl groups,
C.sub.5-C.sub.12 aryl groups, or the like, or a combination or
reaction product thereof, and wherein the salicylic acid compound
is present in an amount sufficient to substantially inhibit
corrosion; and water, wherein the contacting occurs at a
temperature and for a time sufficient to clean and/or remove
residue from the previously treated metal-containing substrate.
30. The method of claim 29, wherein the metal-containing substrate
comprises a copper-containing substrate.
31. The method of claim 30, wherein the copper-containing substrate
also comprises a tantalum-containing layer.
32. The method of claim 29, wherein the composition fuirther
comprises an organic acid other than the salicylic acid
compound.
33. The method of claim 29, wherein the substrate is a
semiconductor base material.
34. The method of claim 29, wherein the salicylic acid compound
comprises acetylsalicylic acid.
35. The method of claim 20, wherein the oxidizer comprises
persulfates, organic and inorganic peroxides, oxidized halides,
periodic acid, permanganates, chromates, cerium compounds,
ferricyanides, or combinations thereof.
36. The method of claim 29, wherein the oxidizer comprises a
hydroxylamine or a hydroxylamine derivative having the formula:
6wherein R.sub.1 is hydrogen or a linear, branched, or cyclic
hydrocarbon containing from 1 to 7 carbon atoms, and wherein X and
Y are, independently, hydrogen or a linear, branched, or cyclic
hydrocarbon containing from 1 to 7 carbon atoms, or wherein X and Y
are linked together form a nitrogen-containing heterocyclic 4- to
7-membered ring.
37. The method of claim 29, wherein the metal-containing substrate
comprises a ferroelectric material, a magnetic material, or
both.
38. The method of claim 20, wherein the amount of oxidizer present
is from about 0.01% to about 30% by weight.
39. The method of claim 20, wherein the salicylic acid compound is
present in an amount from about 0.01% to about 5% by weight.
40. The method of claim 36, wherein the oxidizer comprises
hydroxylamine, N-methyl-hydroxylamine, N,N-dimethyl-hydroxylamine,
N-ethyl-hydroxylamine, N,N-diethyl-hydroxylamine, hydroxylamine
nitrate, hydroxylamine sulfate, hydroxylamine phosphate, or a
combination thereof.
41. The method of claim 20, wherein the composition further
comprises at least one of the following: a film-forming agent other
than the salicylic acid compound; a surfactant; a Theological
control agent; a polymeric stabilizer; a surface active dispersing
agent; or a combination thereof.
42. The method of claim 41, wherein the total amount of surfactant
and rheological control agent present is collectively from about
0.05% to about 4% by weight.
43. The method of claim 20, wherein the composition is
substantially free of oxidizers other than hydroxylamine or a
derivative thereof, and wherein the composition is substantially
free of film-forming agents other than the salicylic acid
compound.
44. The method of claim 29, wherein the composition is
substantially free of corrosion inhibiting agents other than the
salicylic acid compound.
Description
FIELD OF THE INVENTION
[0001] The invention relates to compositions and methods for
chemical-mechanical polishing/planarization and/or post-CMP
cleaning of metal-containing substrates with a composition
containing an oxidizer and an organic or inorganic acid, and more
particularly to compositions and methods for chemical-mechanical
polishing/planarization and/or post-CMP cleaning of
copper-containing substrates used in integrated circuit
manufacture.
BACKGROUND OF THE INVENTION
[0002] Chemical-mechanical polishing or planarization (CMP)
processes are well-known. See, for example, Chemical Mechanical
Polishing in Silicon Processing, Semiconductors and Semimetals,
Vol. 62, Edited by Li, S. et al., which is expressly incorporated
herein by reference. Also directly incorporated by reference for
all purposes are the following commonly assigned patents:
[0003] U.S. Pat. No. 5,891,205 to Picardi et al., which issued on
Apr. 6, 1999, entitled Chemical Mechanical Polishing
Composition;
[0004] U.S. Pat. No. 5,981,454 to Small, which issued on Nov. 9,
1999, entitled Post Clean Treatment Composition Comprising An
Organic Acid And Hydroxylamine;
[0005] U.S. Pat. No. 6,117,783 to Small et al., which issued on
Sep. 12, 2000, entitled Chemical Mechanical Polishing Composition
And Process;
[0006] U.S. Pat. No. 6,156,661 to Small, which issued on Dec. 5,
2000, entitled Post Clean Treatment;
[0007] U.S. Pat. No. 6,235,693 to Cheng et al., which issued on May
22, 2001, entitled Lactam Compositions For Cleaning Organic And
Plasma Etched Residues For Semiconductor Devices;
[0008] U.S. Pat. No. 6,248,704 to Small et al., which issued on
Jun. 19, 2001, entitled Compositions For Cleaning Organic And
Plasma Etched Residues For Semiconductors Devices;
[0009] U.S. Pat. No. 6,251,150 to Small et al., which issued on
Jun. 26, 2001, entitled Slurry Composition And Method Of Chemical
Mechanical Polishing Using Same;
[0010] U.S. Pat. No. 6,313,039 to Small et al., which issued on
Nov. 6, 2001, entitled Chemical Mechanical Polishing Composition
And Process; and
[0011] U.S. Pat. No. 6,498,131 to Small et al., which issued on
Dec. 24, 2002, entitled Composition For Cleaning Chemical
Mechanical Planarization Apparatus.
[0012] CMP processes are commonly used to polish or "planarize" the
surfaces of wafers at various stages of fabrication to improve
wafer yield, performance and reliability. In CMP, typically the
wafer is held in place on a mount using negative pressure, such as
vacuum, or hydrostatic or pneumatic pressure. The mount is
typically situated over a polishing pad. CMP generally involves
applying a polishing composition or slurry to the polishing pad,
establishing pressure-contact between the composition- or
slurry-coated wafer surface and the polishing pad while providing
relative motion, typically rotational or orbital motion, between
the wafer surface and the polishing pad.
[0013] The polishing composition typically contains an abrasive
material, such as silica, ceria, and/or alumina particles, in an
acidic, neutral, or basic solution. Merely by way of example, a
polishing composition useful in the CMP of tungsten material on a
substrate may contain abrasive alumina, also called aluminum oxide,
an oxidizing agent such as hydrogen peroxide, and either potassium
hydroxide or ammonium hydroxide. A CMP process employing such a
polishing composition may provide a predictable rate of polishing,
while largely preserving desirable features on the wafer
surface.
[0014] For such a semiconductor wafer, a typical CMP process
involves polishing the metal in a controlled manner to
preferentially etch certain conductors, insulators or both over the
the oxide beneath the metal, such that the metal is substantially
coplanar with the oxide and remains in the grooves or stud vias of
the oxide. After CMP, the substantially coplanar surface is ready
for further processing. CMP is currently the primary method used to
polish or "planarize" wafers in back end of the line (BEOL)
processes.
[0015] Semiconductor fabrication processes such as photolithography
have evolved significantly, such that advanced devices having very
fine oxide, metal, and other surface features, with sub-0.25 micron
geometries (such as 0.18 micron or less), are now being made.
Process tolerances are necessarily tighter for these advanced
devices, calling for improvements in CMP technology to obtain
desired material removal rates while minimizing wafer defects or
damage. A variety of approaches have been taken in an effort to
improve CMP processes to improve planarity.
[0016] On the other hand, economic forces are requiring the use of
faster processing. One approach has involved increasing the
downward pressure on the wafer carrier in order to increase
material removal rates. This approach is generally disfavored as
the requisite downward pressure is considered too high and too
likely to cause wafer damage, such as scratching, delamination, or
destruction of material layers on the wafer. When the wafer is
fragile, as is generally the case with substrates layered with
films such as porous films having a low dielectric constant, these
damage issues are particularly acute and detrimental in terms of
wafer yield and performance. Generally, faster chemical-mechanical
polishing results in more defects.
[0017] Additional approaches have involved using various protected
combinations of oxidizers, chelators, corrosion inhibitors,
solvents, and other chemicals in the slurry, various abrasives
including for example a zirconium abrasive or mixed abrasives,
and/or using point-of-use mixing techniques. These approaches are
generally undesirable, as they typically complicate CMP in terms of
tooling and process control for example, consume more process time,
and/or increase costs.
[0018] Chelators act on the metal surface of the substrate to turn
metal oxides water soluble. Examples of chelators include a wide
range of organic acids, such as salicylic acid, see e.g. U.S.
patent application Ser. Nos. 09/795,421;. 09/859,147; 10/393,074
& 10/246,280. Other approaches have included the use of
phosphoric acid as well as organic acids. U.S. patent application
Ser. No. 10/396,410. Chelators may be used in conjunction with
oxidizers. When an oxidizer and chelator are used in combination,
excessive corrosion of the substrate may result. As a solution to
this problem, corrosion inhibitors may be added to the composition.
For the typical CMP substrate--copper--examples of corrosion
inhibitors include imidazole or benzothiazole. Addition of such
corrosion inhibitors can be cumbersome often requiring a
specialized method. See e.g. JP-A-11-21546. Furthermore, the
chemistry of CMP compositions may limit the group of suitable
corrosion inhibitors.
[0019] U.S. Pat. No. 5,417,877 describes organic stripping
compositions for use in stripping polymeric material, where the
composition comprises polar organic solvents, basic amines, and
inhibitors, wherein the broad class of inhibitors described
includes salicylic acid compounds.
[0020] U.S. Patent Publication No. 2003/0130147 describes stripping
and residue removing compositions having 1) glycol ethers, alcohols
having a cyclic alkoxy group, alcohols having a heterocyclic oxy
group containing nitrogen or sulfur as the hetero atom, or alcohols
having a cyclic ether structure containing at least oxygen as the
hetero atom; and 2) anticorrosives selected from aromatic hydroxyl
compounds, acetylenic alcohol, carboxyl-group-containing organic
compounds such as quinaldinic acid, triazole-based compounds,
and/or purine-based compounds, and may optionally contain any of
water, an organic acid of which salycilic acid is an example, and
amines.
[0021] U.S. Patent Publication No. 2002/0019202 describes a
two-step CMP method for semi-conductors with composition that can
include complexing agents such as salicylic acid,
3-hydroxy-salicylic acid, or 3,5-hydroxy-salicylic acid, inter
alia, but preferably citric acid, and corrosion inhibitors such as
substituted or unsubstituted benzotriazoles, preferably
benzotriazole.
[0022] U.S. Patent Publication Nos. 2001/0024933 and 2003/0181046
describe a CMP composition and method that contains an oxidizing
agent, an organic polymer removal rate suppressant, and optionally
a complexing agent, which can include salicylic acid,
3-hydroxy-salicylic acid, or 3,5-hydroxy-salicylic acid,
ethylenediamine, and ethyl acetoacetate, inter alia.
[0023] U.S. Patent Publication Nos. 2002/0016073 and 2003/0186497
describe compositions and methods for polishing semiconductors
containing an oxidizer, phosphoric acid, organic acid, a corrosion
inhibition, and water. While salicylic acid is listed as one of the
organic acids in these publications, it is not a preferred acid,
nor is it mentioned as a corrosion inhibitor.
[0024] U.S. Patent Publication No. 2003/0041526 describes a
polishing composition having an index of degree of sedimentation
from 80 to 100 and which can contain an abrasive, water, and
optionally a 2-20 carbon atom hydroxy-functional or
mercapto-functional carboxylic acid. While salicylic acid is listed
as one of the functional carboxylic acids in this publication, it
is not a preferred acid.
[0025] U.S. Patent Publication No. 2002/0017630 discloses a liquid
abrasive composition containing (1) an oxidizing agent for a metal,
(2) a dissolving agent for an oxidized metal, (3) a first
protecting film-forming agent such as an amino acid or an azole
which adsorbs physically on the surface of the metal and/or forms a
chemical bond, to thereby form a protecting film, (4) a second
protecting film-forming agent such as polyacrylic acid, polyamido
acid or a salt thereof which assists the first protecting
film-forming agent informing a protecting film and (5) water. While
salicylic acid is listed as one of the dissolving agents in this
publication, it is not disclosed as being a preferred organic acid
for this purpose.
[0026] U.S. Patent Publication No. 2001/0014534 stripper
composition containing: an anticorrosive agent containing (a) urea
or a urea derivative and (b) a hydroxy aromatic compound;
optionally (c) a hydroxylamine or an alkanolamine; and optionally
(d) water. While salicylic acid is listed as one of the hydroxy
aromatic compounds in this publication, it is not a preferred
element of the anticorrosive agent.
[0027] U.S. Patent Publication No. 2003/0181345 describes a CMP
solution for removing tantalum barrier materials that contains up
to 25 wt % of an oxidizer, up to 15 wt % of an inhibitor for a
nonferrous metal, up to 20 wt % of a complexing agent for the
nonferrous metal, 0.01 to 12 wt % of a tantalum removal agent, up
to 5 wt % of an abrasive, up to 15 wt of polymeric or
polymer-coated particles, and the balance water. While salicylic
acid, 3-hydroxysalicylic acid, and 3,5-dihydroxysalicylic acid are
listed as examples of complexing agents in this publication, none
are preferred complexing agents, nor are any mentioned as
non-ferrous metal corrosion inhibitors.
[0028] U.S. Patent Publication No. 2002/0169088 describes a
cleaning composition comprises a carboxylic acid, an
amine-containing compound, a phosphonic acid, and water. While
salicylic acid (a monocarboxylic acid) is listed as one of the
carboxylic acids in this publication, the publication teaches that
preferred acids contain at least two carboxylic acid groups, with
three carboxylic acid groups being even more preferred.
[0029] U.S. Patent Publication No. 2002/0034925 discloses a
semiconductor polishing process using a slurry composition
comprising abrasives dispersed in an a medium. According to the
publication, the abrasive can be made of organic matter, which may
include, inter alia, acetylsalicylic acid and salts of salicylic
acids.
[0030] U.S. Patent Publication No. 2003/0171239 discloses methods
and compositions for treating a surface of a substrate by foam
technology using a liquid composition containing a gas; a
surfactant; and at least one component selected from the group
consisting of a fluoride, a hydroxylamine, an amine, and periodic
acid.
[0031] U.S. Patent Publication No. 2003/0137052 discloses a method
for semi-conductor manufacturing that includes: a CMP step using a
composition containing quinaldinic acid, lactic acid, colloidal
silica, hydrogen peroxide, and optionally benzotriazole, followed
by an oxygen-rich water polish; a post-CMP cleaning step using at
least one of an organic acid (that can include, inter alia,
salicylic acid), an inorganic acid, and an alkali, optionally a
surface-active agent, and optionally a separate chelating agent
such as EDTA; and a rinsing step using an oxygen-rich aqueous
solution.
[0032] U.S. Patent Publication No. 2003/0130147 discloses a
stripping composition containing a hydroxy-functional ether
compound, an anticorrosive agent, and optionally a weak organic or
inorganic acid. While salicylic acid is listed as one of the weak
organic acids in this publication, it is not a preferred optional
acid component.
[0033] Another approach has involved increasing the amount of
oxidizing agent used in the CMP slurry in an effort to increase
chemical removal of targeted material. This approach is largely
disfavored as the use of increased amounts of oxidizing agents
increase material costs and also detrimentally add to the handling
issues and environmental issues associated with many oxidizing
agents and also increase costs.
[0034] It is generally known that oxidizers admixed in a solution
can provide synergistic etching rates. While ferric salts, cerium
salts, peroxides, persulfates, or hydroxylamines form the oxidizing
capacity of most commercially available CMP slurries, those of
ordinary skill in the art have long known that these oxidizers can
be admixed with others in this group and also with other oxidizers,
and the resulting composition can show synergistic results.
[0035] Certain metals, such as those with a tendency to plate on or
be absorbed on to at least one part of the substrate, are more
damaging than other metals. The industry has developed methods to
remove a portion of the metallic contamination, for example by:
physical desorption by solvents; changing the surface charge with
either acids or bases so that Si----OH or M----OH group can be
protonated (made positive) in acid or made negative with bases by
removing the proton; ion competition, for example removing adsorbed
metal ions by adding acid (i.e. ion exchange); subsequent oxidation
of metals to change the chemical bonds between the impurities and
substrate surface; and subsequent etching the surface, wherein the
impurity and a certain thickness of the substrate surface is
removed, as described in U.S. Pat. No. 6,313,039, the contents of
which has been incorporated herein by reference. This patent taught
the synergistic use of combinations of oxidizers, partticularly
non-transition-metal-containing oxidizers, including a ammonium
persulfate/peroxymonosulfate system; a hydroxylamine
nitrate/hydroxylamine system; an ammonium persulfate/periodic acid
system (for example at 0.5% to 2% periodic acid concentrations; a
hydrogen peroxide/hydroxylamine system; an ammonium
persulfate/potassium periodate system; and an ammonium
persulfate/potassium iodate system. There have been various
"post-polishing cleaners" developed to remove metallic
contamination, but removal of all undesired metal ions is
substantially beyond the range of cleaners, and as the size of the
structures continues to decrease, even a very small number of
metallic atoms deposited on a surface will result in undesired
shorts or current leakage.
[0036] Therefore, despite the known advantages of having multiple
oxidizers, for example a metal-containing oxidizer admixed with
either another metal-containing oxidizer or with a
non-metal-containing oxidizer, there has been a tendency in the
industry to reduce the amount of metal ions in CMP slurries.
Additionally, metal ion-containing fluids are often environmentally
undesirable and expensive treatment may be needed prior to waste
disposal of used product.
[0037] Chemical-mechanical planarization (CMP) and post-CMP
cleaning have become key steps in the fabrication of high-speed
integrated circuits. The oxidant in CMP slurries plays a critical
role in controlling the removal rate and planarity of metal films
that are polished. Recently, hydroxylamine-(NH2OH--) based oxidants
have been introduced for chemical mechanical polishing of copper.
See, e.g., International Publication No. WO 98/04646 and M. L.
Peterson et al., Semiconductor Fabtech, 11th ed. (2000), the entire
contents of which are hereby incorporated by reference for all
purposes. The etch rate and CMP removal rate of copper in.
hydroxylamine based solutions is a strong function of pH and
exhibits a maximum in the vicinity of pH 6. See, e.g., W. Huang et
al., Chemical Mechanical Planarization in IC DEVICE MANUFACTURING
III, PV 99-37, p. 101, The Electrochemical Society Proceedings
Series, Pennington, N.J. (1999). The removal rates at pH 6 can be
modulated through the use of a corrosion inhibitor such as
benzotriazole (BTA). While BTA has been known to be a very good
corrosion inhibitor for copper for many decades, due to certain
environmental limitations imposed by this compound, the CMP
industry has been looking for alternatives to BTA.
[0038] EKC Technology/Dupont Electronic Technologies, a large
commercial manufacturer of CMP slurries, sells several high-purity,
non-metal-based CMP slurries for tungsten, for example the
MicroPlanar.RTM. CMP3550.TM./ MicroPlanar.RTM. CMP3510.TM. slurry,
as well as the traditional but effective ferric nitrate as the
oxidizer with a post-CMP cleaner to remove metal contaminants.
[0039] Further developments in the field of CMP technology are
desired. Alternative corrosion inhibitor additives for use in metal
free oxidizer-based, for example hydrogen peroxide-based, CMP
solutions/slurries are addressed herein.
SUMMARY OF THE INVENTION
[0040] The invention provides a method for chemically polishing
mechanically polishing a metal-containing substrate comprising
contacting a metal-containing substrate with a composition
comprising: an oxidizing agent; between about 0.0001 M to about 1 M
of a salicylic acid compound, wherein the salicylic acid compound
is present in an amount sufficient to substantially inhibit
corrosion and water, at a temperature and for a time sufficient to
chemically mechanically polish the metal-containing substrate.
[0041] The invention further provides a method of cleaning a
metal-containing substrate that had previously undergone a chemical
mechanical polishing process comprising the steps of contacting the
chemically mechanically polished metal-containing substrate with a
composition comprising: an oxidizer; a salicylic acid compound and
water, at a temperature and for a time sufficient to clean the
metal-containing substrate.
[0042] The invention further provides a method of a post-etch
residue removal for a metal-containing substrate comprising the
steps of contacting the chemically mechanically polished
metal-containing substrate with a composition comprising of: an
oxidizer; a salicylic acid compound; and water at a at a
temperature and for a time sufficient to remove post-etch residue
from the metal-containing substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Benzotriazole (BTA) is a well-known corrosion inhibitor for
copper in various applications in a wide-range of environments. The
chemistry of interaction of benzotriazole (BTA) with copper has
been studied extensively. See, e.g., G. W. Poling, Corros. Sci.,
(1970), 10, p.359, and V. Brusic et al., Electrochem. Soc., (1991),
138, p.2253. It is generally accepted that BTA (as well as BTA-ion)
chemisorbs on the copper surface and forms an insoluble cuprous
surface complex. Under certain conditions the formation of a thick,
multilayered coating has been confirmed. See, e.g., V. Brusic et
al., Electrochem. Soc., (1991), 138, p.2253.
[0044] One aspect of the present invention includes a composition,
e.g., used in a method for chemical mechanical polishing of a
metal-containing substrate, particularly of copper-containing
substrates, containing: between about 0.01% and about 30% by weight
of an oxidizing agent based on weight of fluid; between about
0.00001M to about 0.5M, preferably from about 0.00005M to about
0.05M, for example from about 0.00005M to about 0.001M, from about
0.0001M to about 0.01M, from about 0.0001M to about 0.001M, from
about 0.001M to about 0.01M, or from about 0.01M to about 0.5M of
salicylic acid or a salicylic acid derivative; water; and
optionally an abrasive.
[0045] Generally, any quantity of salicylic acid and/or its
derivative(s), particularly salicylic acid, can act as a chelator
while there can typically be a certain minimum quantity before the
salicylic acid and/or its derivative(s), for example salicylic
acid, can become effective as a corrosion inhibitor.
[0046] Generally, a quantity greater than about 0.005M, preferably
greater than about 0.01M, of salicylic acid will function as a
corrosion inhibitor. When used in a CMP step on a copper-containing
substrate, for example, the amount of salicylic acid and/or its
derivative(s) present can advantageously be at least sufficient to
chelate at least about 50% of the copper chemically and/or
mechanically polished from the substrate during the CMP process,
for example such that not more than about 300 ppm of unchelated
copper ions are present in the CMP solution/slurry, more preferably
at least about 75% of the available copper ions in solution and/or
such that not more than about 100 ppm, or not more than about 50
ppm of unchelated copper ions are present in the CMP
solution/slurry. When used for example in shallow trench isolation
(STI) processes, it is advantageous to have sufficient salicylic
acid and/or its derivative compounds available to act as a
corrosion inhibitor.
[0047] When used in a post-CMP cleaning step of a copper-containing
substrate, the fluid advantageously contains an oxidizer, and
includes an amount of salicylic acid and/or its derivative(s) also
advantageously sufficient to at least partially inhibit corrosion
of at least a portion of the copper-containing substrate (or of a
copper-containing layer of a multi-layer substrate) during the
cleaning process, preferably to substantially inhibit corrosion of
the copper-containing portion(s) of the substrate. As used herein,
the term "substantially" should be understood to refer to a level
of at least about 30%, preferably a level of at least about 70%,
more preferably a level of at least about 90%, for example a level
of at least about 95% compared to the corrosion observed using a
solution without the salicylic acid compound. In a preferred
embodiment, the term "substantially" can mean completely.
Generally, any quantity of salicylic acid and/or its derivative(s),
particularly salicylic acid, can act as a chelator while there can
typically be a certain minimum quantity before the salicylic acid
and/or its derivative(s), particularly salicylic acid, can become
effective as a corrosion inhibitor. The amount of salicylic acid
and/or its derivative(s) can be from about 0.00001M to about 1 M,
for example from about 0.05M to about 0.2M, alternatively from
about 0.00005M to about 0.001M, from about 0.001M to about 0.01M,
alternatively from about 0.01M to about 0.1M, alternatively from
about 0.1M to about 0.5M. A quantity greater than about 0.005M,
preferably greater than about 0.01M, of salicylic acid will be most
useful as a corrosion inhibitor.
[0048] The composition according to the invention can be used on a
metal-containing substrate, preferably a copper-containing
substrate and/or a tantalum-containing substrate (e.g., copper,
copper alloys such as Cu--Al, tantalum, tantalum nitrides, tantalum
oxynitrides, tantalum oxides, tantalum alloys, and the like, and
combinations thereof). The composition can contain an oxidizing
agent, preferably an organic or inorganic peroxide such as hydrogen
peroxide, a corrosion inhibitor substitute for benzotriazole,
preferably a salicylic acid and/or a derivative thereof such as
salicylic acid, water, and optionally an abrasive. When used as a
CMP slurry, it is preferred that the composition contain an
abrasive. However, it is envisioned that the CMP composition may be
used in conjunction with an abrasive polishing pad (e.g., a
polishing pad having abrasive particles attached thereto or
contained therein), in which case the abrasive in the slurry may be
unnecessary and therefore optional. When used in a post-CMP
cleaner, generally the abrasive is not desired.
[0049] The present invention can be used in conjunction with any
suitable substrate. In particular, the present invention can be
used in conjunction with memory or rigid disks, metals (e.g., noble
metals), ILD layers, integrated circuits, semiconductor devices,
semiconductor wafers, micro-electro-mechanical systems,
ferroelectrics, magnetic heads, polymeric films, and low and high
dielectric constant films, and technical or optical glass. Suitable
substrates comprise, for example, a metal, metal oxide, metal
composite, or mixtures thereof. The substrate can comprise, consist
essentially of, or consist of any suitable metal. Suitable metals
include, for example, copper, aluminum, titanium, tungsten,
tantalum, gold, platinum, iridium, ruthenium, and combinations
(e.g., alloys or mixtures) thereof. The substrate also can
comprise, consist essentially of, or consist of any suitable metal
oxide. Suitable metal oxides include, for example, alumina, silica,
titania, ceria, zirconia, germania, magnesia, and coformed products
thereof, and mixtures thereof. In addition, the substrate can
comprise, consist essentially of, or consist of any suitable metal
composite and/or metal alloy. Suitable metal composites and metal
alloys include, for example, metal nitrides (e.g., tantalum
nitride, titanium nitride, and tungsten nitride), metal carbides
(e.g., silicon carbide and tungsten carbide), nickel-phosphorus,
alumino-borosilicate, borosilicate glass, phosphosilicate glass
(PSG), borophosphosilicate glass (BPSG)), silicon/germanium alloys,
and silicon/germanium/carbon alloys. The substrate also can
comprise, consist essentially of, or consist of any suitable
semiconductor base material. Suitable semiconductor base materials
include single-crystal silicon, poly-crystalline silicon, amorphous
silicon, silicon-on-insulator, and gallium arsenide. Glass
substrates can also be used in conjunction with the present
invention including technical glass, optical glass, and ceramics,
of various types known in the art.
[0050] The formulations are particularly useful on substrates
comprising, consisting essentially of, or consisting of copper, a
copper alloy, and/or a copper compound, and the substrate may also
contain one or more barrier materials as are known in the art, such
as Ta, TaN, Ti, TiN, or combinations thereof
[0051] The present invention can be used to polish any part of a
substrate (e.g., a semiconductor device) at any stage in the
production of the substrate. For example, the present invention can
be used to polish a semiconductor device in conjunction with
shallow trench isolation (STI) processing, as set forth, for
example, in U.S. Pat. Nos. 5,498,565; 5,721,173; 5,938,505; and
6,019,806, or in conjunction with the formation of an interlayer
dielectric.
[0052] The present invention, incorporated into a chemical
mechanical polishing composition, a post-etch residue remover, or a
post-CMP cleaner, can be used in conjunction with any suitable
component (or ingredient) known in the art for each category, for
example, abrasives, oxidizing agents, catalysts, film-forming
agents, complexing agents, Theological control agents, surfactants
(i.e., surface-active agents), polymeric stabilizers, pH-adjusters,
and other appropriate ingredients.
[0053] The abrasive, when present in the compositions according to
the embodiments used for chemical mechanical polishing, can be any
suitable abrasive known in the CMP art. For example, suitable
abrasives can include, but are not limited to, silica, ceria,
alumina, zirconia, titania, metal coated particles thereof (e.g.,
iron-coated silica), magnesia, co-formed products thereof, mixtures
thereof, and chemical admixtures thereof. The term "chemical
admixture" refers to particles including atomically mixed or coated
metal oxide abrasive mixtures. Suitable abrasives also include
heat-treated abrasives and chemically-treated abrasives (e.g.,
abrasives with chemically-linked organic functional groups).
[0054] The amount of abrasive, when present in the compositions
according to the invention, can advantageously be from about 0.01%
to about 30% by weight, preferably from about 0.01% to about 10%,
for example from about 0.01% to about 5% or from about 0.1% to
about 10%. In some embodiments according to the invention, the
composition can be substantially free of abrasives.
[0055] The abrasive can be produced by any suitable technique known
to one of ordinary skill in the art. The abrasive can be derived,
for example, from any process known in the art, including flame
processes, sol-gel processes, hydrothermal processes, plasma
processes, aerogel processes, fuming processes, precipitation
processes, mining, and combinations of processes thereof. The
abrasive can be a condensation-polymerized metal oxide, e.g.,
condensation-polymerized silica. A suitable abrasive also can
comprise, consist essentially of, or consist of high-temperature
crystalline phases of alumina consisting of gamma, theta, delta,
and alpha alumina, and/or low-temperature phases of alumina
consisting of all non-high temperature crystalline alumina
phases.
[0056] The abrasive can be combined with any suitable carrier
(e.g., an aqueous carrier) to form a "dispersion" (e.g., a
"slurry"). Suitable dispersions can have any suitable concentration
of abrasive.
[0057] The abrasive can have any suitable abrasive particle
characteristics depending on the desired polishing effects. In
particular, the abrasive can have any suitable surface area. A
suitable abrasive surface area, for example, is a surface area
ranging from about 5 m.sup.2/g to about 430 m.sup.2/g, as
calculated from the method of S. Brunauer, P. H. Emrnet, and I.
Teller, J. Am. Chemical Society, 60, 309 (1938). Alternatively, it
is also suitable for the abrasive to have essentially a bimodal
particle size distribution.
[0058] Any suitable oxidizing agent can be used in conjunction with
the present invention. Suitable oxidizing agents include, for
example, oxidized halides (e.g., chlorates, bromates, iodates,
perchlorates, perbromates, periodates, fluoride-containing
compounds, and mixtures thereof, and the like). Suitable oxidizing
agents also include, for example, perboric acid, periodic acid,
periodates, perborates, percarbonates, nitrates (e.g., iron (III)
nitrate, and hydroxylamine nitrate), persulfates (e.g., ammonium
persulfate), organic peroxides such as benzoyl peroxide, inorganic
peroxides such as hydrogen peroxide, peroxyacids (e.g., peracetic
acid, perbenzoic acid, m-chloroperbenzoic acid, salts thereof,
mixtures thereof, and the like), permanganates, chromates, cerium
compounds, ferricyanides (e.g., potassium ferricyanide), mixtures
thereof, and the like. Suitable oxidizers also include
hydroxylamine, hydroxylamine derivatives, and/or salts thereof
Examples of suitable hydroxylamine or hydroxylamine derivative
include hydroxylamine, N-methyl-hydroxylamine,
N,N-dimethyl-hydroxylamine, N-ethyl-hydroxylamine,
N,N-diethyl-hydroxylamine, hydroxylamine nitrate, hydroxylamine
sulfate, hydroxylamine phosphate. Suitable oxidizers can often be
mixtures of two or more of the above-listed oxidizers, in a range
of from about 100:1 to about 1:100. The amount of suitable
oxidizing agent or agents can be between about 0.01% to about 30%,
e.g., between 0.01% and about 2%, alternatively between about 2%
and about 5%, alternatively between about 5% and about 10%,
alternatively between about 10% and about 17.5%, alternatively
between about 17.5% and about 25%, alternatively between about 25%
and about 30%.
[0059] Any suitable film-forming agent (i.e., corrosion-inhibitor)
can be used in conjunction with the present invention,
supplementing the film-forming capacity of the salicylic acid
and/or its derivative(s). Suitable film-forming agents include, for
example, heterocyclic organic compounds (e.g., organic compounds
with one or more active functional groups, such as heterocyclic
rings, particularly nitrogen-containing heterocyclic rings).
Suitable film-forming agents also include, for example,
benzotriazole, triazole, benzimidazole, and mixtures thereof. In
one embodiment, the film-forming agent can be present in an amount
from about 0.05% to about 10% (exclusive of the salicylic acid
and/or its derivative compounds according to this invention) by
weight based on the weight of the fluid.
[0060] Any suitable complexing agent (i.e., chelating agent or
selectivity enhancer) can be used in conjunction with the present
invention, supplementing the chelating capacity of the salicylic
acid and/or its derivative(s). Suitable complexing agents include,
for example, carbonyl compounds (e.g., acetylacetonates and the
like), simple carboxylates (e.g., acetates, aryl carboxylates, and
the like), carboxylates containing one or more hydroxyl groups
(e.g., glycolates, lactates, gluconates, gallic acid and salts
thereof, and the like), di-, tri-, and poly-carboxylates (e.g.,
oxalates, phthalates, citrates, succinates, tartrates, maleates,
glycolates, edetates such as disodium EDTA, mixtures thereof, and
the like), carboxylates containing one or more sulfonic and/or
phosphonic groups, and carboxylates, di-, tri-, or poly-alcohols
(e.g., ethylene glycol, pyrocatechol, pyrogallol, tannic acid, and
the like), phosphate-containing compounds (e.g., phosphonium salts,
phosphonic acids, and the like), amine-containing compounds (e.g.,
amino acids, amino alcohols, di-, tri-, and poly-amines, and the
like), or mixtures thereof. In one embodiment, a complexing agent
can be present in an amount from about 0.005% to about 5% by weight
(exclusive of the salicylic acid and/or its derivative compounds
according to this invention) based on the weight of the fluid.
[0061] Any suitable surfactant and/or rheological control agent can
be used in conjunction with the present invention, including
viscosity enhancing agents and coagulants. Suitable rheological
control agents include, for example, polymeric rheological control
agents. Moreover, suitable rheological control agents include, for
example, urethane polymers (e.g., urethane polymers with a
molecular weight greater than about 100,000 Daltons), acrylates
comprising one or more acrylic subunits (e.g., vinyl acrylates and
styrene acrylates), polymers, copolymers, and oligomers thereof,
and salts thereof. Suitable surfactants include, for example,
cationic surfactants, anionic surfactants, anionic
polyelectrolytes, nonionic surfactants, amphoteric surfactants,
fluorinated surfactants, mixtures thereof, and the like. In one
embodiment, the surfactant and/or rheological control agent can be
present in an amount from about 0.005% to about 4% by weight based
on the weight of the fluid.
[0062] The composition used in conjunction with the present
invention can contain any suitable polymeric stabilizer or other
surface active dispersing agent, for example, phosphoric acid,
organic acids, tin oxides, organic phosphonates, and the like, and
mixtures thereof. In one embodiment, the polymeric stabilizer can
be present in an amount from about 0.01% to about 3% by weight
based on the weight of the fluid.
[0063] Any of the components used in conjunction with the present
invention can be provided in the form of a mixture or solution in
an appropriate carrier liquid or solvent (e.g., water or an
appropriate organic solvent).
[0064] Furthermore, as mentioned, the compounds, alone or in any
combination, can be used as a component of a polishing, residue
removing or cleaning composition. Two or more components then are
individually stored and subsequently mixed to form a polishing or
cleaning composition at, or immediately before reaching, the
point-of-use.
[0065] A component can have any pH appropriate in view of the
storage and contemplated end-use, as will be appreciated by those
of skill in the art. Moreover, the pH of a component used in
conjunction with the present invention can be adjusted in any
suitable manner, e.g., by adding a pH adjuster, regulator, or
buffer. Suitable pH adjusters, regulators, or buffers include
acids, such as, for example, hydrochloric acid, acids such as
mineral acids (e.g., nitric acid, sulfuric acid, phosphoric acid,
and the like), and organic acids (e.g., acetic acid, citric acid,
malonic acid, succinic acid, tartaric acid, oxalic acid, glycolic
acid, and the like). Suitable pH adjusters, regulators, or buffers
also include bases, such as, for example, inorganic hydroxide bases
(e.g., sodium hydroxide, potassium hydroxide, ammonium hydroxide,
and the like) and carbonate bases (e.g., sodium carbonate and the
like). In one preferred embodiment, the composition contains an
organic acid such as acetic acid.
[0066] As described above, various embodiments of the invention can
contain other additives, including, but not limited to, polar
organic solvents, non-polar organic solvents, surfactants,
chelating agents and/or corrosion inhibitors other than salicylic
acids and their derivatives, non-hydroxyl-containing amines, other
hydroxyl-containing amines such as alkanolamines, organic and/or
inorganic acids and/or bases (e.g., to control pH), oxidizing
agents other than hydroxylamine or its derivatives, ammonium salts,
mono-, di-, tri-, and/or tetra- alkylammonium salts, or the like,
or a combination thereof. In a preferred embodiment, the above
described compositions can also be substantially free from one or
more of the following: polar organic solvents; non-polar organic
solvents; surfactants; chelating agents and/or corrosion inhibitors
other than salicylic acids and their derivatives;
non-hydroxyl-containing amines; other hydroxyl-containing amines
such as alkanolamines; organic and/or inorganic acids and/or bases
(e.g., to control pH); oxidizing agents other than organic or
inorganic peroxides such as hydrogen peroxide; ammonium salts; and
mono-, di-, tri-, and/or tetra- alkylammonium salts.
[0067] The polishing and cleaning components described herein can
be combined in any manner and proportion to provide one or more
compositions suitable for polishing or cleaning a substrate (e.g.,
a semiconductor substrate).
[0068] Another aspect of the present invention includes a
composition, e.g., used for chemical mechanical polishing or
post-CMP cleaning, particularly of copper-containing substrates,
containing an organic or inorganic peroxide such as hydrogen
peroxide, salicylic acid and/or its derivative(s), particularly
salicylic acid, water, an organic acid such as acetic acid, and
optionally an abrasive such as silica. When used in a CMP step on a
copper-containing substrate, the amount of salicylic acid and/or
its derivative(s) present is advantageously sufficient to chelate a
portion of the copper chemically and/or mechanically polished from
the substrate during the CMP process, preferably at least about 50%
of the available copper ions in solution and/or such that not more
than about 100 ppm of unchelated copper ions are present in the CMP
solution/slurry, more preferably at least about 75% of the
available copper ions in solution and/or such that not more than
about 50 ppm of unchelated copper ions are present in the CMP
solution/slurry. When used in a post-CMP cleaning step of a
copper-containing substrate, the amount of salicylic acid and/or
its derivative(s), particularly salicylic acid, present is
advantageously sufficient to inhibit corrosion of at least a
portion of the copper-containing substrate (or of a
copper-containing layer of a multi-layer substrate) during the
cleaning process, preferably to substantially inhibit corrosion of
the copper-containing portion(s) of the substrate. As used herein,
the term "substantially inhibit" should be understood to refer to
inhibiting static corrosion to a level of at least about 30%,
preferably a level of at least about 70%, more preferably a level
of at least about 90%, for example a level of at least about 95%
less than is observed with a similar composition not containing the
salicylic acid. In a preferred embodiment, the term "substantially"
can mean completely.
[0069] Advantageously, the composition according to the invention
can be an aqueous solution containing salicylic acid and/or its
derivative(s), and an organic or inorganic peroxide such as
hydrogen peroxide, or an aqueous slurry containing salicylic acid
and/or its derivative(s), an organic or inorganic peroxide such as
hydrogen peroxide, and an abrasive. In one embodiment, the
composition consists essentially of water, acetic acid, salicylic
acid, and hydrogen peroxide. In another embodiment, the composition
consists essentially of water, acetic acid, salicylic acid,
hydrogen peroxide, and an abrasive such as silica.
[0070] The amount of organic and/or inorganic peroxide in the
compositions according to the invention can advantageously be from
about 0.01M to about 3M, preferably from about 0.01M to about 1M,
for example from about 0.05M to about 0.5M. As used herein, the
designation "M" refers to molarity, which is typically expressed in
moles per liter of composition. In an alternate embodiment, the
amount of organic and/or inorganic peroxide in the compositions
according to the invention can advantageously be from about 0.01%
to about 25% by weight, preferably from about 0.03% to about 15% by
weight, for example from about 0.03% to about 0.5% by weight, from
about 0.1% to about 1% by weight, from about 1% to about 15% by
weight, from about 0.1% to about 5% by weight, from about 0.5% to
about 5% by weight, from about 0.03% to about 1% by weight, or from
about 10% to about 15% by weight.
[0071] Salicylic acid compound derivatives are compounds having the
general formula: 1
[0072] where R.sup.1 and R.sub.2 can independently be hydrogen; an
organic salt/counterion such as ammonium, a mono-, di-, tri-, or
tetra- C.sub.1-C.sub.8 alkyl ammonium, or the like; an inorganic
salt/counterion such as sodium, potassium, lithium, a phosphonium,
or the like; a C.sub.1-C.sub.20 linear or branched, saturated or
unsaturated, optionally singly or multiply substituted alkyl
moiety; a C.sub.5-C.sub.20 optionally singly or multiply
substituted aryl or heteroaryl moiety; or a combination thereof,
and where R.sub.3 is a hydrogen, a C.sub.1-C.sub.20 linear or
branched, saturated or unsaturated, optionally singly or multiply
substituted alkyl moiety, a C.sub.5-C.sub.20 optionally singly or
multiply substituted aryl or heteroaryl moiety, or a combination
thereof. Optionally substituted moieties can include, but are not
limited to hydroxyls, nitro groups, sulfates, phosphates, amines,
amides, carboxylic acids, carboxylate salts, carboxylate esters,
halides, alkyl or aryl ethers, C.sub.1-C.sub.6 linear or branched,
saturated or unsaturated alkyl groups, C.sub.5-C.sub.12 aryl
groups, or the like, or a combination or reaction product thereof.
In one preferred embodiment, R.sub.1, R.sub.2, and R.sub.3 are all
hydrogen (i.e., which results in salicylic acid). In another
preferred embodiment, R.sub.2 and R.sub.3 are both hydrogen and
R.sub.1 is a an inorganic salt/counterion.
[0073] Salicylic acid compounds according to the invention can
additionally or alternately include complexes of salicylic acid
(i.e., R.sub.1, R.sub.2, and R.sub.3 are all hydrogen, as above)
with other molecules, e.g., triethanolamine. In addition, another
salicylic acid compound according to the invention is salicylic
hydrazide, where the --OR.sub.1 moiety in the structure above is
replaced by an --NH--NH.sub.2 moiety.
[0074] The amount of salicylic acid and/or its derivative(s) in the
polishing, residue removing and post-CMP cleaning compositions
according to the invention can advantageously be from about
0.00001M to about 1M, preferably from about 0.00005M to about 0.5M,
for example from about 0.00005M to about 0.001M, from about 0.001M
to about 0.01M, from about 0.01M to about 0.1M, or from about 0.1M
to about 0.5M. In an alternate embodiment, the amount of salicylic
acid and/or its derivative(s) in the compositions according to the
invention can advantageously be from about 0.01% to about 25% by
weight, preferably from about 0.03% to about 15% by weight, for
example from about 0.03% to about 0.5% by weight, from about 0.1%
to about 1% by weight, from about 1% to about 15% by weight, from
about 0.1% to about 5% by weight, from about 0.5% to about 5% by
weight, from about 0.03% to about 1% by weight, or from about 10%
to about 15% by weight. Generally, any quantity of salicylic acid
and/or its derivative(s), particularly salicylic acid, can act as a
chelator while there is typically a certain minimum quantity before
the salicylic acid and/or its derivative(s), particularly salicylic
acid, can become effective as a corrosion inhibitor. The quantity
useful for inhibiting corrosion on a particular substrate with a
particular quantity of oxidizer will be readily ascertainable by
one of ordinary skill in the art having the benefit of this
disclosure.
[0075] One particular embodiment comprises adding glacial salicylic
acid (aspirin) to a CMP composition, residue removing composition,
and or post-CMP cleaning composition in an amount sufficient to
chelate metals within the composition and preferably, in an amount
sufficient to substantially inhibit corrosion of metal, e.g.,
copper, on the substrate. A chelating amount may be from about
0.01% to about 2%, typically about 0.01% to about 1%. Corrosion
inhibiting amounts are typically from about 4% to about 10%.
Intermediate values have both functions.
[0076] Aspects of the invention relating to a method for chemically
mechanically planarizing-or polishing a metal-containing substrate,
comprise contacting a copper-containing substrate with a
composition according to the invention for a time and at a
temperature sufficient to planarize, and polish copper-containing
surface thereof. In a preferred embodiment, compositions useful for
this method can include an abrasive such as silica.
[0077] Another aspect of the invention relates to a method for
cleaning a previously chemically-mechanically planarized or
polished copper-containing substrate that includes contacting the
polished substrate with a composition according to the invention
for a time and at a temperature sufficient to planarize, polish, or
clean a copper-containing surface thereof. In a preferred
embodiment, compositions useful for this method can be
substantially free of an abrasive.
[0078] The method of CMP includes contacting the fluid or slurry
comprising the oxidizer and salicylic acid and/or its derivative(s)
with the substrate under movable conditions, where the fluid or
slurry is typically between the substrate and a pad that move
relative to one another, to polish substrate material.
[0079] Any suitable polishing pad can be used in conjunction with
the present invention. In particular, the polishing pad can be
woven or non-woven and can comprise any suitable polymer of varying
density, hardness, thickness, compressibility, ability to rebound
upon compression, and compression modulus. The polishing pad used
in conjunction with the present invention preferably has a density
of about 0.6 to about 0.95 g/cm.sup.3, a Shore A hardness rating of
less than about 100 (e.g., about 40 to about 90), a thickness of at
least about 0.75 mm (e.g., about 0.75 to about 3 mm),
compressibility of about 0 to about 10% (by volume), the ability to
rebound to at least about 25% (by volume) (e.g., about 25% to about
100%) after compression at about 35 kPa, and a compression modulus
of at least about 1000 kPa. Examples of suitable polymers include
polyurethanes, polymelamines, polyethylenes, polyesters,
polysulfones, polyvinyl acetates, polyacrylic acids,
polyacrylamides, polyvinylchlorides, polyvinylfluorides,
polycarbonates, polyamides, polyethers, polystyrenes,
polypropylenes, nylons, fluorinated hydrocarbons, and the like, and
mixtures, copolymers, and grafts thereof. Preferably, the polishing
pad comprises a polyurethane polishing surface. The polishing pad
and/or surface can be formed from such materials using suitable
techniques recognized in the art, for example, using thermal
sintering techniques. Furthermore, the polishing pad formed from
such materials can be substantially porous (e.g., having open or
closed pores) or substantially non-porous. Porous pads preferably
have a pore diameter of about 1 to about 1000 microns and a pore
volume of about 15% to about 70%. The polishing pad and/or surface
also can be perforated or unperforated to any degree. Preferably,
the polishing pad comprises a perforated polishing surface.
[0080] The method of post clean treatment involves contacting the
substrate, after the CMP process, with the post CMP cleaner under
conditions to remove the CMP slurry.
* * * * *