U.S. patent application number 10/421355 was filed with the patent office on 2004-05-06 for nonlithographic method to produce masks by selective reaction, articles produced, and composition for same.
This patent application is currently assigned to International Business Machines Corporation. Invention is credited to Colburn, Matthew E., Gates, Stephen M., Hedrick, Jeffrey C., Huang, Elbert, Nitta, Satyanarayana V., Purushothaman, Sampath, Sankarapandian, Muthumanickam.
Application Number | 20040087177 10/421355 |
Document ID | / |
Family ID | 29270362 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040087177 |
Kind Code |
A1 |
Colburn, Matthew E. ; et
al. |
May 6, 2004 |
Nonlithographic method to produce masks by selective reaction,
articles produced, and composition for same
Abstract
A method for forming a self aligned pattern on an existing
pattern on a substrate comprising applying a coating of the masking
material to the substrate; and allowing at least a portion of the
masking material to preferentially attach to portions of the
existing pattern. The pattern is comprised of a first set of
regions of the substrate having a first atomic composition and a
second set of regions of the substrate having a second atomic
composition different from the first composition. The first set of
regions may include one or more metal elements and the second set
of regions may include a dielectric. The masking material may
comprise a polymer containing a reactive grafting site that
selectively binds to the portions of the pattern. The masking
material may include a polymer that binds to the portions of the
pattern to provide a layer of functional groups suitable for
polymerization initiation, a reactive molecule having functional
groups suitable for polymerization propagation, or a reactive
molecule, wherein reaction of the reactive molecule with the
portion of the pattern generates a layer having reactive groups,
which participate in step growth polymerization. Structures in
accordance with the method. Compositions for practicing the
method.
Inventors: |
Colburn, Matthew E.;
(Hopewell Junction, NY) ; Gates, Stephen M.;
(Ossining, NY) ; Hedrick, Jeffrey C.; (Montvale,
NJ) ; Huang, Elbert; (Tarrytown, NY) ; Nitta,
Satyanarayana V.; (Poughquag, NY) ; Purushothaman,
Sampath; (Yorktown Heights, NY) ; Sankarapandian,
Muthumanickam; (Yorktown Heights, NY) |
Correspondence
Address: |
PAUL D. GREELEY, ESQ.
OHLANDT, GREELEY, RUGGIERO & PERLE, L.L.P.
10TH FLOOR
ONE LANDMARK SQUARE
STAMFORD
CT
06901-2682
US
|
Assignee: |
International Business Machines
Corporation
|
Family ID: |
29270362 |
Appl. No.: |
10/421355 |
Filed: |
April 24, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10421355 |
Apr 24, 2003 |
|
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10287935 |
Nov 5, 2002 |
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6641899 |
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Current U.S.
Class: |
438/758 ;
428/195.1; 438/778; 438/780 |
Current CPC
Class: |
B82Y 30/00 20130101;
H01L 21/0331 20130101; H01L 21/31058 20130101; Y10T 428/24802
20150115; H05K 3/0079 20130101; Y10T 428/24917 20150115; Y10T
428/24926 20150115; H01L 21/76849 20130101; G03F 7/165
20130101 |
Class at
Publication: |
438/758 ;
428/195.1; 438/778; 438/780 |
International
Class: |
H01L 021/31; H01L
021/469 |
Claims
What is claimed is:
1. A method for forming a self aligned pattern on an existing
pattern on a substrate having a top surface comprising: applying a
coating of said masking material to said top surface of said
substrate; and allowing at least a portion of said masking material
to preferentially attach to portions of said existing pattern to
said top surface.
2. The method of claim 1, wherein said pattern applied to said top
surface is comprised of a first set of regions of the substrate
having a first atomic composition and a second set of regions of
the substrate having a second atomic composition different from the
first composition.
3. The method of claim 2, wherein said masking material comprises a
self-assembled monolayer that selectively binds to said second set
of regions of said pattern.
4. The method of claim 2, wherein said first set of regions
includes one or more metal elements and wherein said second set of
regions includes a dielectric.
5. The method of claim 2, wherein said masking material comprises a
polymer containing a reactive grafting site that selectively binds
to said second set of regions of said pattern applied to said top
surface.
6. The method of claim 5, wherein said polymer is selected from the
group consisting of: poly(oxides), poly(carbonates), poly(esters),
poly(anhydrides), poly(urethanes), poly(sulfonates),
poly(siloxanes), poly(sulfides), poly(thioethers),
poly(thioesters), poly(sulfones), poly(sufonamides), poly(amides),
poly(imines), poly(ureas), poly(phosphazenes), poly(silanes),
poly(siloxanes), poly(silazanes), poly(nitriles), poly(imides),
poly(oxazoles), poly(benzoxazoles), poly(thiazoles),
poly(pyrazoles), poly(triazoles), poly(thiophenes),
poly(oxadiazoles), poly(thiazines), poly(thiazoles),
poly(quionoxalines), poly(benzimidazoles), poly(oxindoles),
poly(indolines), poly(pyridines) poly(triazines),
poly(piperazines), poly(pyridines), poly(piperdines),
poly(pyrrolidines), poly(carboranes), poly(fluoresceins),
poly(acetals), and poly(anhydrides).
7. The method of claim 5, wherein said polymer has a reactive
functional group serving as said grafting site, said functional
group being selected from the group consisting of: acyl chlorides,
anhydrides, hydroxys, esters, ethers, aldehydes, ketones,
carbonates, acids, epoxies, aziridines, phenols, amines, amides,
imides, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, nitros, azos, benzophenones, acetals, ketals,
diketones, and organosilanes (Si.sub.xL.sub.yR.sub.z,) where L is
selected from the group consisting of hydroxy, methoxy, ethoxy,
acetoxy, alkoxy, carboxy, amines, halogens, R is selected from the
group consisting of hydrido, methyl, ethyl, vinyl, and phenyl (any
alkyl or aryl).
8. The method of claim 1, wherein said masking material includes a
polymer that is generated from a reactive molecule that binds to
said portions of said pattern to provide a layer of functional
groups.
9. The method of claim 8, wherein said layer is a molecular
monolayer.
10. The method of claim 8, wherein the said reactive molecule is
bifunctional and includes a first moiety that binds to said
portions of said pattern and a second moiety that serves as a
polymerization initiator.
11. The method of claim 10, wherein the said first moiety that
binds to said portions of said pattern is selected from the group
consisting of acyl chlorides, anhydrides, hydroxys, esters, ethers,
aldehydes, ketones, carbonates, acids, epoxies, aziridines,
phenols, amines, amides, imides, isocyanates, thiols, sulfones,
halides, phosphines, phosphine oxides, nitros, azos, benzophenones,
acetals, ketals, diketones, and
organosilanes(Si.sub.xL.sub.yR.sub.z,) where L is selected from the
group consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy,
carboxy, amines, halogens, R is selected from the group consisting
of hydrido, methyl, ethyl, vinyl, and phenyl (any alkyl or
aryl).
12. The method of claim 10, wherein the said second moiety that
serves as a polymerization initiator is selected from the group
consisting of peroxides, nitroxides, halides, azos, peresters,
thioesters, hydroxy; metal organics having the stoichiometry of RX
where R may consist of: benzyl, cumyl, butyl, alkyl, napthalene,
and X may consist of sodium, lithium, and potassium; protonic
acids, lewis acids, carbenium salts, tosylates, triflates,
benzophenones, aryldiazonium, diaryliodonium, triarylsulfonium,
acetals, ketals, and diketones.
13. The method of claim 10, further comprising applying a reactive
monomer to said layer of functional groups, so that said reactive
monomer polymerizes on said layer.
14. The method of claim 13, wherein said reactive monomer is a
substituted ethylenic organic molecule.
15. The method of claim 13, wherein said reactive monomer comprises
a monomeric ring.
16. The method of claim 13, wherein said reactive monomer
polymerizes when exposed to one of a free radical, an anion, a
cation, or a transition metal catalyst.
17. The method of claim 13, wherein said reactive monomer
polymerizes when exposed to thermal annealing or irradiation.
18. The method of claim 13, wherein said reactive monomer is
selected from the group consisting of: dienes, alkenes, acrylics,
methacrylics, acrylamides, methacrylamides, vinylethers, vinyl
alcohols, ketones, acetals, vinylesters, vinylhalides,
vinylnitriles, styrenes, vinyl pyridines, vinyl pyrrolidones, vinyl
imidazoles, vinylheterocyclics, cyclic lactams, cyclic ethers,
cyclic lactones, cycloalkenes, cyclic thioesters, cyclic
thioethers, aziridines, phosphozines, siloxanes, oxazolines,
oxazines, thiiranes, capolactones, propylene glycol, and a
substituted ethylenic organic molecule.
19. The method of claim 8, further comprising applying a reactive
monomer which undergoes polymerization on said layer.
20. The method of claim 19, wherein said polymerization comprises a
chain growth mechanism wherein polymerization proceeds through
addition of a monomer to a reactive polymer.
21. The method of claim 1, wherein said masking material includes a
reactive molecule having functional groups suitable for
polymerization propagation.
22. The method of claim 21, wherein said reactive molecule is
comprised of a first moiety that binds the reactive molecule to
said portions of said existing pattern, and a second moiety that
serves as a monomeric unit.
23. The method of claim 22, wherein said first moiety that binds
the reactive molecule to said portions of said existing pattern is
selected from the group consisting of: carboxylic acids. acyl
chlorides, anhydrides, hydroxys, esters, ethers, aldehydes,
ketones, carbonates, acids, epoxies, aziridines, phenols, amines,
amides, imides, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, nitros, azos, benzophenones, acetals, ketals,
diketones, organosilanes, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, phenyl (any alkyl or aryl).
24. The method of claim 22, wherein said second moiety that serves
as a monomeric unit comprises a substituted ethylenic organic
molecule.
25. The method of claim 22, wherein said second moiety that serves
as a monomeric unit comprises a monomeric ring.
26. The method of claim 22, wherein said reactive monomer
polymerizes when exposed to one of a free radical, an anion,
cation, or a transition metal catalyst.
27. The method of claim 22, wherein said reactive monomer
polymerizes when exposed to thermal annealing or irradiation.
28. The method of claim 22, wherein said second moiety that serves
as a monomeric unit is selected from the group consisting of:
dienes, alkenes, acrylics, methacrylics, acrylamides,
methacrylamides, vinylethers, vinyl alcohols, ketones, acetals,
vinylesters, vinylhalides, vinylnitriles, styrenes, vinyl
pyridines, vinyl pyrrolidones, vinyl imidazoles,
vinylheterocyclics, styrene, cyclic lactams, cyclic ethers, cyclic
lactones, cycloalkenes, cyclic thioesters, cyclic thioethers,
aziridines, phosphozines, siloxanes, oxazolines, oxazines, and
thiiranes.
29. The method of claim 21, wherein said polymerization comprises a
chain growth mechanism wherein polymerization proceeds through
addition of a monomer to a reactive polymer.
30. The method of claim 21, wherein said reactive molecule is
deposited as a thin layer or a molecular monolayer.
31. The method of claim 1, wherein said masking material includes a
composition wherein polymerization proceeds by reactions that
combine monomers and polymers having two or more functionalities
that react with each other to produce polymers of a larger
molecular weight.
32. The method of claim 1, wherein said masking material comprises
a reactive molecule, wherein reaction of the reactive molecule with
the portion of the pattern generates a layer having reactive
groups, which participate in step growth polymerization.
33. The method of claim 32, further comprising applying a reactive
monomer, having one or more functionalities to the layer a form a
self aligned mask layer.
34. The method of claim 33, wherein the one or more functionalities
react with each other to form a covalent bond.
35. The method of claim 32, wherein the reactive molecule comprises
a first moiety that binds the reactive molecule to the portions of
the pattern, and a second moiety that serves as a reaction
site.
36. The method of claim 35, wherein the first moiety that binds to
portions of the pattern is selected from the group consisting of:
organosilanes, hydroxy, acyl chlorides, and carboxylic acids.
37. The method of claim 35, wherein the second moiety that serves
as a reaction site is selected from the group consisting of:
amines, nitrites, alcohols, carboxylic acids, sulfonic acids,
isocyanates, acyl chlorides, esters, amides, anhydrides, epoxies,
halides, acetoxy, vinyl, and silanols
38. The method of claim 33, wherein the functionalities are
provided by one or more functional groups selected from the group
consisting of: amines, nitriles, alcohols, acids, carboxylic acids,
sulfonic acids, isocyanates, acyl chlorides, esters, amides,
anhydrides, epoxies, halides, acetoxy, vinyl, and silanols.
39 The method of claim 33, wherein said reactive monomer
polymerizes when exposed to thermal annealing or irradiation.
40. The method of claim 1, further comprising preparing a polymer
to act as said masking material.
41. The method of claim 40, further comprising forming a condensed
phase containing said polymer, and contacting said portions of said
pattern with said condensed phase.
42. The method of claim 41, wherein said condensed phase is a
liquid.
43. The method of claim 42, wherein said liquid is a solvent for
said polymer.
44. The method of claim 1, further comprising: preparing a reactive
molecule.
45. The method of claim 44, further comprising forming a condensed
phase containing said reactive molecule, and contacting said
portions of said pattern with said condensed phase.
46. The method of claim 45, wherein said condensed phase is a
liquid.
47. The method of claim 46, wherein said liquid is a solvent for
said reactive molecule.
48. The method of claim 44, wherein the reactive molecule is
prepared in a vapor phase.
49. The method of claim 1, further comprising: preparing a reactive
monomer.
50. The method of claim 49, further comprising forming a condensed
phase containing said reactive monomer, and contacting said
portions of said pattern having said layer with said condensed
phase.
51. The method of claim 50, wherein said condensed phase is a
liquid.
52. The method of claim 51, wherein said liquid is a solvent for
said reactive monomer
53. The method of claim 49, wherein the reactive monomer is
prepared in a vapor phase.
54. The method of claim 1, further comprising removing the masking
material from portions of said pattern to which it does not
attach.
55. The method of claim 54, wherein said removing is accomplished
by at least one of rinsing, ultrasonication, dissolution,
thermolysis, irradiation, and annealing.
56. The method of Claim 1, wherein the masking material is applied
to the substrate by a method selected from: spin-coating, scan
coating, dip coating, spray coating, and using a doctor blade.
57. The method of Claim 1, wherein said pattern is comprised of a
first set of regions of the substrate having a first atomic
composition and a second set of regions of the substrate having a
second atomic composition different from the first composition and
wherein the areas of second atomic composition comprises copper and
are patterned electrical interconnects.
58. The method of Claim 1, wherein the substrate is selected from
the following: a silicon wafer containing microelectronic devices ,
a ceramic chip carrier, an organic chip carrier, a glass substrate,
a gallium arsenide substrate, a silicon carbide substrate, a
semiconductor wafer, a circuit board, or a plastic substrate.
59. The method of claim 1, further comprising chemically treating
regions of the substrate prior to applying said coating.
60. The method of claim 59, wherein said chemically treating
comprises at least one of plasma treatment, application of an
oxidizing or reducing solution, annealing in a reducing or
oxidizing atmosphere, and application of a material that renders
surface portions of the substrate, to which it is applied, to be
hydrophobic or hydrophillic.
61. The method of claim 59, wherein said chemically treating
changes the wetting characteristics of the regions of the
substrate.
62. The method of claim 59, wherein said chemically treating in
order to modify said second regions comprises applying an
organosilane comprised of Si.sub.xL.sub.yR.sub.z, where L is
selected from the group consisting of hydroxy, methoxy, ethoxy,
acetoxy, alkoxy, carboxy, amines, halogens, R is selected from the
group consisting of hydrido, methyl, ethyl, vinyl, and phenyl (any
alkyl or aryl).
63. The method of claim 59, wherein said chemically treating in
order to modify said second regions comprises applying a material
selected from the group consisting of: hexamethyl disilazane,
hexaphenyl disilazane, vinyltriacetoxysilane,
aminopropyltrimethoxysilane, trimethychlorosilane,
trimethylacetoxysilane and halogenated alkyl silanes.
64. The method of claim 59, wherein said chemically treating in
order to modify said first regions comprises applying one of
hydroxys, esters, ethers, aldehydes, ketones, carbonates, acids,
phenols, amines, amides, imides, thioesters, thioethers, ureas,
urethanes, nitriles, isocyanates, thiols, sulfones, halides,
phosphines, phosphine oxides, phosphonimides, nitros, azos,
thioesters, thioethers, benzotriazole, pyridines, imidazoles,
imides, oxazoles, benzoxazoles, thiazoles, pyrazoles, triazoles,
thiophenes, oxadiazoles, thiazines, thiazoles, quionoxalines,
benzimidazoles, oxindoles, indolines, nitrogenous compounds, ans
phosphoric acids.
65. The method of claim 59, wherein said chemically treating
comprises at least one of thermal annealing and irradiating.
66. The method of claim 65, wherein said irradiating comprises
exposure to one of ultraviolet light, visible light, x-rays, and
electrons.
67. The method of claim 1, wherein the coating comprises a polymer
that covalently bonds to said portions of said pattern.
68. A structure comprising: a self aligned pattern on an existing
pattern on a substrate, said self aligned pattern including a
masking material having an affinity for portions of said existing
pattern, so that said masking material preferentially reactively
grafts to said portions of said existing pattern.
69. The structure of claim 68, wherein said pattern is comprised of
a first set of regions of the substrate having a first atomic
composition and a second set of regions of the substrate having a
second atomic composition different from the first composition.
70. The structure of claim 69, wherein said first set of regions
includes one or more metal elements and wherein said second set of
regions includes a dielectric.
71. The structure of claim 70, wherein said self-aligned pattern is
disposed upon said second set of regions.
72. The structure of claim 70, wherein said self-aligned pattern is
disposed only upon said second set of regions.
73. The structure of claim 70, wherein said self-aligned pattern is
not disposed upon said first set of regions.
74. The structure according to Claim 68, comprising at least one
conductive feature, formed on said substrate, with the substrate
further comprising at least one insulating layer surrounding said
conductive feature.
75. The structure according to Claim 74, wherein said insulating
layer surrounds said at least one conductive feature at its bottom
and lateral surfaces.
76. The structure according to Claim 74, further comprising at
least one conductive barrier layer disposed at, at least one
interface between said insulating layer and said at least one
conductive feature.
77. A structure according to Claim 74, where the combination of the
at least one conductive feature and the insulating layers, is
repeated to form a multilevel interconnect stack.
78. The structure according to Claim 77, further comprising at
least one conductive barrier layer disposed at, at least one
interface between said insulating layer and said at least one
conductive feature.
79. The structure according to Claim 68, wherein said substrate is
one of a microelectronic device chip, a ceramic chip carrier, and
an organic chip carrier.
80. A composition for selectively coating a pattern on a substrate,
said composition comprising: a carrier material for application to
said substrate; and a polymer in said carrier that reactively
grafts to regions of said substrate having first chemical
characteristics.
81. The composition of claim 62, wherein said polymer is an
amorphous polymeric system having any chain architecture.
82. The composition of claim 81, wherein said polymer is one of
linear, networked, branched, and dendrimeric.
83. The composition of claim 81, wherein said polymer has an
acyclic main chain.
84. The composition of claim 83, wherein said polymer is selected
from the group consisting of poly(dienes), poly(alkenes),
poly(acrylics), poly(methacrylics), poly(acrylamides),
poly(methacrylamides), poly(vinylethers), poly(vinyl alcohols),
poly(ketones), poly(acetals), poly(vinylesters),
poly(vinylhalides), poly(vinylnitriles), poly(styrenes), poly(vinyl
pyridines), poly(vinyl pyrrolidones), poly(vinyl imidazoles), and
poly(vinylheterocyclics).
85. The composition of claim 81, wherein said polymer has a carbon
containing backbone.
86. The composition of claim 81, wherein said polymer has a
carbocyclic main chain.
87. The composition of claim 81, wherein said polymer is a
poly(phenylene).
88. The composition of claim 81, wherein said polymer is a main
chain acyclic hetroatom polymer.
89. The composition of claim 88, wherein said polymer is selected
from the group consisting of poly(oxides), poly(carbonates),
poly(esters), poly(anhydrides), poly(urethanes), poly(sulfonates),
poly(siloxanes), poly(sulfides), poly(thioethers),
poly(thioesters), poly(sulfones), poly(sufonamides), poly(amides),
poly(imines), poly(ureas), poly(phosphazenes), poly(silanes),
poly(siloxanes), poly(silazanes), and poly(nitriles).
90. The composition of claim 81, wherein said polymer is a main
chain heterocyclic polymer.
91. The composition of claim 90, wherein said polymer is selected
from the group consisting of: poly(imides), poly(oxazoles),
poly(benzoxazoles), poly(thiazoles), poly(pyrazoles),
poly(triazoles), poly(thiophenes), poly(oxadiazoles),
poly(thiazines), poly(thiazoles), poly(quionoxalines),
poly(benzimidazoles), poly(oxindoles), poly(indolines),
poly(pyridines) poly(triazines), poly(piperazines),
poly(pyridines), poly(piperdines), poly(pyrrolidines),
poly(carboranes), poly(fluoresceins), poly(acetals), and
poly(anhydrides).
92. The composition of claim 81, wherein said polymer is a step
growth polymer.
93. The composition of claim 92, wherein said polymer is selected
from the group consisting of: poly(oxides), poly(carbonates),
poly(esters), poly(anhydrides), poly(urethanes), poly(sulfonates),
poly(siloxanes), poly(sulfides), poly(thioethers),
poly(thioesters), poly(sulfones), poly(sufonamides), poly(amides),
poly(imines), poly(ureas), poly(phosphazenes), poly(silanes),
poly(siloxanes), poly(silazanes), poly(nitriles), poly(imides),
poly(oxazoles), poly(benzoxazoles), poly(thiazoles),
poly(pyrazoles), poly(triazoles), poly(thiophenes),
poly(oxadiazoles), poly(thiazines), poly(thiazoles),
poly(quionoxalines), poly(benzimidazoles), poly(oxindoles),
poly(indolines), poly(pyridines) poly(triazines),
poly(piperazines), poly(pyridines), poly(piperdines),
poly(pyrrolidines), poly(carboranes), poly(fluoresceins),
poly(acetals), and poly(anhydrides).
94. The composition of claim 81, wherein said polymer contains at
least one monomeric unit.
95. A composition for selectively coating a pattern on a substrate,
said composition comprising: a carrier material for application to
said substrate; and a polymer in said carrier having reactive
functional groups that covalently bond to regions of said substrate
having first chemical characteristics.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is related to the application entitled
"Nonlithographic Method to Produce Self-Aligned Mask, Articles
Produced by Same and Composition for Same" (docket number
YOR920020154US1) by the same inventors as the present invention,
filed on the same day as the present application, and assigned to
the same assignee as the present application and which is
incorporated herein by reference as if fully set forth herein.
FIELD OF THE INVENTION
[0002] This invention relates to the production of patterns on a
substrate having regions with different compositions or different
surface treatment. More particularly, it relates to a method of
producing fine patterns on substrates used in, for example, the
microelectronics industry on which electronic devices are
fabricated. It is also related to devices fabricated in accordance
with the methods. The patterns are fabricated accurately and
inexpensively without the use of lithography. The present invention
also provides many additional advantages, which shall become
apparent as described below.
BACKGROUND OF THE INVENTION
[0003] A number of applications and technologies involve structures
having a well-defined arrangement of chemically distinct components
at the surface of a substrate. A common example is a substrate
surface having metal conductor regions separated by insulator
regions. Normally, these structures are defined by patterning
processes such as lithography, embossing, and stamping, and have
length scales ranging from 10 nanometers to several microns. In
many of these systems it may be necessary or highly beneficial to
apply an additional component or treatment to only one of the
components at the surface. One technique for performing this task
is through the use of a mask to protect regions where this
additional application or treatment is not desired. Effectively,
the mask material directs this treatment to the intended surfaces
that are fully exposed. Unfortunately, typical procedures to
generate a mask by lithographic or other means can be expensive and
error prone. Thus, a method in which these conventional approaches
can be circumvented would be highly advantageous.
[0004] A particular example in which such strategies would be
useful involves integrated circuits comprised of metal and
dielectric components. It is widely known that the speed of
propagation of interconnect signals is one of the most important
factors controlling overall circuit speed as feature sizes are
reduced and the number of devices per unit area is increased.
Throughout the semiconductor industry, there has been a strong
drive to reduce the dielectric constant, k, of the dielectric
materials existing between metal lines and/or to minimize the
thickness of layers having comparatively larger dielectric
constants, e.g., cap barrier layers. Both of these approaches
reduce the effective dielectric constant, k.sub.eff, of the
components between metal lines, and as a result, interconnect
signals travel faster through conductors due to a reduction in
resistance-capacitance (RC) delays. Unfortunately, these strategies
are difficult to implement due to limitations in maintaining
significant properties, i.e., mechanical, barrier, electrical,
etc., that result with a reduction in thickness or change in the
chemistry of the layers.
SUMMARY OF THE INVENTION
[0005] This invention relates to a method to fabricate mask layers
onto a pre-patterned substrate having two or more chemically
distinct surface regions. The mask layer is deposited by a
selective reaction approach that provides self-alignment of the
layers. This method can apply to any technology or application
involving a chemically or physically heterogeneous substrate
including: interconnect structures for high speed microprocessors,
application specific integrated circuits (ASICs), flexible organic
semiconductor chips, and memory storage. Other structures that can
be fabricated utilizing this method include: displays, circuit
boards, chip carriers, microelectromechanical systems (MEMS), chips
for hi-thoughput screening, microfabricated fluidic devices, etc.
The utility of this method stems from a simple and robust means in
which the replication of a patterned substrate to generate a mask
layer can be performed, circumventing the requirement for expensive
and error prone methods, such as lithography. Thus, the present
invention provides an extremely advantageous alternative to the
prior art techniques.
[0006] In the example of integrated circuits, the effective
dielectric constant is reduced by the use of a process wherein
layers are selectively placed upon the metal lines. To do this,
mask layers are first applied to the dielectric or hard mask
surfaces. In accordance with the invention, these layers are
generated by mechanisms involving selective chemical reactions as
described below. The layers can be self-aligned such that
lithographic processes are not required to define the features.
Upon self-alignment on the dielectric/hardmask surfaces, these
layers, can then be used as a mask for subsequent deposition of
other layers which serve as diffusion barriers to copper, oxygen
and/or water, layers which reduce the electromigration attributes
of the metal lines, and seed layers.
[0007] Thus, in the example of integrated circuits, the use of the
self-aligned masks allows a simplified fabrication process in which
the effective dielectric constant between metal lines can be
reduced through selective application of various materials to the
metal lines. This is central to maximizing the propagation speed of
interconnect signals and ultimately provides faster overall circuit
performance. Furthermore, this invention leads to a higher level of
protection and reliability of interconnect structures as the errors
attributed to conventional patterning methods are eliminated and to
reduced processing costs. Although the utilization of the
self-aligned masks is described for integrated circuits, this
method is useful for any application wherein the modification of a
specific component in a pre-patterned substrate is beneficial.
[0008] Thus, the invention is directed to a process wherein a mask
is applied to a pre-patterned substrate, through selective chemical
reactions described below, that replicates the underlining pattern.
This mask can then be utilized for treatment or material deposition
onto specific components of the pre-patterned substrate. The use of
the self-aligned masks allows a unique process in which masks can
be generated without the need to perform additional pattern
defining steps.
[0009] Another application of this invention is its use for
semiconductor packaging substrates which are comprised of
conductors (usually copper) and insulators (usually epoxy,
polyimide, alumina, cordierite glass ceramic and the like) disposed
adjacent to each other. Commonly, the conductors must be protected
from external ambients and processing exposures such as soldering
and wet etching. This protection can be achieved by using the
various methods of forming selective coatings on the conductor.
Alternately, selective coating on the dielectric by one of the
exemplary methods can leave the metal exposed for further
processing by methods such as electroless plating to add additional
metal layers such as nickel, cobalt, palladium, gold and others on
top, without exposing the dielectrics to these process steps. The
ability to accomplish these selective modifications without the use
of lithographic processing leads to cost reductions and is
particularly advantageous in microelectronic packaging, which is
very cost sensitive.
[0010] Although the utilization of the self-aligned masks is
described for microelectronic parts, this method is useful for any
application whereby the modification of a specific component in a
pre-patterned substrate is beneficial.
[0011] Thus, this invention is directed to a method for forming a
self aligned pattern on an existing pattern on a substrate
comprising applying a coating of the masking material to the
substrate; and allowing at least a portion of the masking material
to preferentially attach to portions of the existing pattern. The
pattern may be comprised of a first set of regions of the substrate
having a first atomic composition and a second set of regions of
the substrate having a second atomic composition different from the
first composition. The first set of regions may include one or more
metal elements and the second set of regions may include a
dielectric. The first regions may comprise copper and may be
patterned electrical interconnects.
[0012] According to the present invention, the masking material may
comprise a polymer containing a reactive grafting site that
selectively binds to the portions of the pattern. The polymer may
be that of an amorphous polymeric system having chain architecture
(including linear, networked, branched and dendrimeric) and may
contain one or more monomeric units. The polymer may be selected
from the group consisting of polystyrenes, polymethacrylates,
polyacrylates, and polyesters, as well as others mentioned below.
The polymer may have a reactive functional group serving as the
grafting site, the functional group being selected from the group
consisting of: acyl chlorides, anhydrides, hydroxys, esters,
ethers, aldehydes, ketones, carbonates, acids, epoxies, aziridines,
phenols, amines, amides, imides, isocyanates, thiols, sulfones,
halides, phosphines, phosphine oxides, nitros, azos, benzophenones,
acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, phenyl (any alkyl or aryl).
[0013] The method may further comprise preparing a polymer to act
as the masking material, forming a condensed phase containing the
polymer, and contacting the portions of the pattern with the
condensed phase. The condensed phase may be a liquid. The liquid
may be a solvent for the polymer.
[0014] In accordance with another aspect of the invention, the
masking material may include a reactive molecule that binds to the
portions of the pattern to provide a layer of functional groups
suitable for polymerization initiation. The layer may be a
molecular monolayer. The reactive molecule may include a first
moiety that binds to the portions of the pattern and a second
moiety that serves as a polymerization initiator. The first moiety
that binds to the portions of the pattern may be selected from the
group consisting of acyl chlorides, anhydrides, hydroxys, esters,
ethers, aldehydes, ketones, carbonates, acids, epoxies, aziridines,
phenols, amines, amides, imides, isocyanates, thiols, sulfones,
halides, phosphines, phosphine oxides, nitros, azos, benzophenones,
acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, phenyl (any alkyl or aryl). The
second moiety that serves as a polymerization initiator may be
selected from the group consisting of peroxides, nitroxides,
halides, azos, peresters, thioesters, hydroxy; metal organics
having the stoichiometry of RX where R may consist of: benzyl,
cumyl, butyl, alkyl, napthalene, and X may consist of sodium,
lithium, and potassium; protonic acids, lewis acids, carbenium
salts, tosylates, triflates, benzophenones, aryldiazonium,
diaryliodonium, triarylsulfonium, acetals, ketals, and
diketones.
[0015] The method may comprise applying a reactive monomer to the
layer of functional groups, so that the reactive monomer
polymerizes on the layer to form a self-aligned mask layer. The
polymerization may comprise a chain growth mechanism wherein
polymerization proceeds through addition of a monomer to a reactive
polymer. The reactive monomer may be any molecule that polymerizes
by a chain growth process and may be a substituted ethylenic
organic molecule, one of a monomeric ring, a mixture of similar or
dissimilar molecules that react with each other to form a covalent
bond, and may be oligomeric or polymeric. The reactive monomer may
be one that polymerizes when exposed to one of a free radical, an
anion, transition metal catalyst, or a cation. The reactive monomer
may also be one that polymerizes when exposed to thermal annealing
or irradiation. The reactive monomer may be selected from the group
consisting of: dienes, alkenes, acrylics, methacrylics,
acrylamides, methacrylamides, vinylethers, vinyl alcohols, ketones,
acetals, vinylesters, vinylhalides, vinylnitriles, styrenes, vinyl
pyridines, vinyl pyrrolidones, vinyl imidazoles,
vinylheterocyclics, styrene, cyclic lactams, cyclic ethers, cyclic
lactones, cycloalkenes, cyclic thioesters, cyclic thioethers,
aziridines, phosphozines, siloxanes, oxazolines, oxazines, and
thiiranes.
[0016] The method may further comprise applying the reactive
monomer in a condensed phase, and contacting the portions of the
pattern with the condensed phase. The condensed phase may be a
liquid. The liquid may be a solvent for the polymer. Alternatively,
the method may further comprise applying the reactive monomer in a
vapor phase.
[0017] In accordance with another aspect of the invention, the
masking material may include a reactive molecule having functional
groups suitable for polymerization propagation. The reactive
molecule may be comprised of a first moiety that will bind the
reactive molecule to the portions of the existing pattern, and a
second moiety that serves as a monomeric unit. The first moiety may
be selected from the group consisting of: acyl chlorides,
anhydrides, hydroxys, esters, ethers, aldehydes, ketones,
carbonates, acids, epoxies, aziridines, phenols, amines, amides,
imides, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, nitros, azos, benzophenones, acetals, ketals,
diketones, and organosilanes (Si.sub.xL.sub.yR.sub.z,) where L is
selected from the group consisting of hydroxy, methoxy, ethoxy,
acetoxy, alkoxy, carboxy, amines, halogens, R is selected from the
group consisting of hydrido, methyl, ethyl, vinyl, phenyl (any
alkyl or aryl). The second moiety may be comprised of a monomer,
and may be selected from the group consisting of, dienes, alkenes,
acrylics, methacrylics, acrylamides, methacrylamides, vinylethers,
vinyl alcohols, ketones, acetals, vinylesters, vinylhalides,
vinylnitriles, styrenes, vinyl pyridines, vinyl pyrrolidones, vinyl
imidazoles, vinylheterocyclics, styrene, cyclic lactams, cyclic
ethers, cyclic lactones, cycloalkenes, cyclic thioesters, cyclic
thioethers, aziridines, phosphozines, siloxanes, oxazolines,
oxazines, and thiiranes,
[0018] The reactive monomer polymerizes when exposed to one of a
free radical, an anion, a transition metal catalyst, or a cation.
The reactive monomer may be one that polymerizes when exposed to
thermal annealing or irradiation. The polymerization of the
reactive monomer with the second moiety of the reactive molecule,
which serves as a monomeric unit, provides a mechanism where
polymerization through the surface bound groups occurs to form a
self-aligned mask layer. The reactive monomer may be any monomer
that polymerizes by a chain growth process and may be selected from
the group consisting of dienes, alkenes, acrylics, methacrylics,
acrylamides, methacrylamides, vinylethers, vinyl alcohols, ketones,
acetals, vinylesters, vinylhalides, vinylnitriles, styrenes, vinyl
pyridines, vinyl pyrrolidones, vinyl imidazoles,
vinylheterocyclics, styrene, cyclic lactams, cyclic ethers, cyclic
lactones, cycloalkenes, cyclic thioesters, cyclic thioethers,
aziridines, phosphozines, siloxanes, oxazolines, oxazines, and
thiiranes.
[0019] The addition of initiator can be utilized for polymerization
or the polymerization can be driven thermally. The initiator may be
selected from the group consisting of peroxides, nitroxides,
halides, azos, peresters, thioesters, hydroxy; metal organics
having the stoichiometry of RX where R may consist of: benzyl,
cumyl, butyl, alkyl, napthalene, and X may consist of sodium,
lithium, and potassium; protonic acids, lewis acids, carbenium
salts, tosylates, triflates, benzophenones, aryldiazonium,
diaryliodonium, triarylsulfonium, acetals, ketals, and
diketones.
[0020] The method may further comprise applying the reactive
monomer and initiator in a condensed phase, and contacting the
portions of the pattern with the condensed phase. The condensed
phase may be a liquid. The liquid may be a solvent for the polymer.
Alternatively, a vapor phase may be used.
[0021] In accordance with another aspect of the invention, the
masking material includes a composition wherein polymerization
proceeds by a step growth process whereby reactions that combine
monomers and polymers having two or more functionalities that react
with each other to produce polymers of a larger molecular weight.
The masking material comprises a reactive molecule, wherein
reaction of the reactive molecule with the portion of the pattern
generates a layer having reactive groups, which participate in step
growth polymerization. The reactive molecule comprises a first
moiety that binds the reactive molecule to the portions of the
pattern, and a second moiety that serves as a reaction site. The
first moiety that binds to portions of the pattern may be selected
from the group consisting of: acyl chlorides, anhydrides, hydroxys,
esters, ethers, aldehydes, ketones, carbonates, acids, epoxies,
aziridines, phenols, amines, amides, imides, isocyanates, thiols,
sulfones, halides, phosphines, phosphine oxides, nitros, azos,
benzophenones, acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, phenyl (any alkyl or aryl),hydroxy.
The second moiety that serves as a reaction site may be selected
from the group consisting of: amines, nitriles, alcohols,
carboxylic acids, sulfonic acids, isocyanates, acyl chlorides,
esters, amides, anhydrides, epoxies, halides, acetoxy, vinyl, and
silanols. The method further comprises applying a reactive monomer,
having one or more functionalities to the layer a form a
self-aligned mask layer. The one or more functionalities react with
each other to form a covalent bond. The reactive monomer may be one
that polymerizes when exposed to thermal annealing or
irradiation.
[0022] The reactive monomer may be comprised of at least two
functional groups which may be dissimilar and may be a mixture of
dissimilar molecules and may be comprised of functional groups
consisting of: amines, nitriles, alcohols, carboxylic acids,
sulfonic acids, isocyanates, acyl chlorides, esters, amides,
anhydrides, epoxies, halides, acetoxy, vinyl, and silanols.
[0023] The method may further comprise applying the reactive
monomer in a condensed phase, and contacting the portions of the
pattern with the condensed phase. The condensed phase may be a
liquid. The liquid may be a solvent for the polymer. Alternatively,
a vapor phase may be used. In general, a vapor phase is used only
when applying the reactive monomer to functional groups, and not
when polymer is applied.
[0024] The method may further comprise removing the masking
material from portions of the pattern to which it does not attach.
The removing may be accomplished by at least one of rinsing,
ultrasonication, dissolution, thermolysis, irradiation,
decomposition and related removal methods known in the art.
Application of the masking material to the substrate may be
accomplished by any means known in the art for example:
spin-coating, dip coating, spray coating, scan coating, and using a
doctor blade. Other methods may be used within the invention.
[0025] The method may further comprise chemically treating regions
of the substrate prior to applying the coating. The chemically
treating may be comprised of at least one of plasma treatment,
application of an oxidizing solution, annealing in an oxidizing or
reducing atmosphere, and application of a material that renders
surface portions of the substrate, to which it is applied,
hydrophobic. The chemical treatment changes the wetting
characteristics of the regions of the substrate. The chemically
treating may comprise applying a molecule having reactive grafting
sites that can covalently bind to the dielectric surface including:
acyl chlorides, anhydrides, hydroxys, esters, ethers, aldehydes,
ketones, carbonates, acids, epoxies, aziridines, phenols, amines,
amides, imides, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, nitros, azos, benzophenones, acetals, ketals,
diketones, and organosilanes (Si.sub.xL.sub.yR.sub.z,) where L is
selected from the group consisting of hydroxy, methoxy, ethoxy,
acetoxy, alkoxy, carboxy, amines, halogens, R is selected from the
group consisting of hydrido, methyl, ethyl, vinyl, and phenyl (any
alkyl or aryl). The method may further comprise chemically treating
regions of the substrate prior to the coating with chemicals that
have an affinity to metals. The include chemicals, such as copper
binding groups having functional groups comprised of hydroxys,
esters, ethers, aldehydes, ketones, carbonates, acids, phenols,
amines, amides, imides, thioesters, thioethers, ureas, urethanes,
nitrites, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, phosphonimides, nitros, azos, thioesters, and
thioethers. The functional groups can be heterocyclics, such as
benzotriazole, pyridines, imidazoles, imides, oxazoles,
benzoxazoles, thiazoles, pyrazoles, triazoles, thiophenes,
oxadiazoles, thiazines, thiazoles, quionoxalines, benzimidazoles,
oxindoles, and indolines.
[0026] The invention is also directed to a structure comprising a
self aligned pattern on an existing pattern on a substrate, the
self aligned pattern including a masking material having an
affinity for portions of the existing pattern, so that the masking
material preferentially reactively grafts to the portions of the
existing pattern. The pattern may be comprised of a first set of
regions of the substrate having a first atomic composition and a
second set of regions of the substrate having a second atomic
composition different from the first composition. The first set of
regions may include one or more metal elements and the second set
of regions may include a dielectric. The self-aligned pattern is
disposed upon the second set of regions or only upon the second set
of regions; that is not upon the first set of regions. The
structure may comprise at least one conductive feature, formed on
the substrate, with the substrate further comprising at least one
insulating layer surrounding the conductive feature. The insulating
layer may surround the at least one conductive feature at its
bottom and lateral surfaces. The structure may further comprise at
least one conductive barrier layer disposed at, at least one
interface between the insulating layer and the at least one
conductive feature. The combination of the at least one conductive
feature and the insulating layers, may be repeated to form a
multilevel interconnect stack.
[0027] The substrate may be one of a silicon wafer containing
microelectronic devices, a ceramic chip carrier, an organic chip
carrier, a glass substrate, a gallium arsenide substrate, a silicon
carbide substrate, or other semiconductor wafer, a circuit board,
or a plastic substrate.
[0028] The invention is also directed to a composition for
selectively coating a pattern on a substrate, the composition
comprising a carrier material for application to the substrate, and
a polymer in the carrier that reactively grafts to regions of the
substrate having first chemical characteristics. The polymer may be
amorphous, may having any chain architecture (including linear,
networked, branched, dendrimeric), and can contain one or more
monomeric units. The polymer may have acyclic main chains (carbon
containing backbones) and may include poly(dienes), poly(alkenes),
poly(acrylics), poly(methacrylics), poly(acrylamides),
poly(methacrylamides), poly(vinylethers), poly(vinyl alcohols),
poly(ketones), poly(acetals), poly(vinylesters),
poly(vinylhalides), poly(vinylnitriles), poly(styrenes), poly(vinyl
pyridines), poly(vinyl pyrrolidones), poly(vinyl imidazoles), and
poly(vinylheterocyclics). If the polymer has a carbocyclic main
chain, it may be, for example, a poly(phenylene). The polymer may
also be a main chain acyclic heteroatom polymer selected from the
group of poly(oxides), poly(carbonates), poly(esters),
poly(anhydrides), poly(urethanes), poly(sulfonates),
poly(siloxanes), poly(sulfides), poly(thioethers),
poly(thioesters), poly(sulfones), poly(sufonamides), poly(amides),
poly(imines), poly(ureas), poly(phosphazenes), poly(silanes),
poly(siloxanes), poly(silazanes), and poly(nitriles). The polymer
may have a heterocyclic main chain and may be selected from the
group of poly(imides), poly(oxazoles), poly(benzoxazoles),
poly(thiazoles), poly(pyrazoles), poly(triazoles),
poly(thiophenes), poly(oxadiazoles), poly(thiazines),
poly(thiazoles), poly(quionoxalines), poly(benzimidazoles),
poly(oxindoles), poly(indolines), poly(pyridines) poly(triazines),
poly(piperazines), poly(pyridines), poly(piperdines),
poly(pyrrolidines), poly(carboranes), poly(fluoresceins),
poly(acetals), and poly(anhydrides).
[0029] The polymer in the carrier may have reactive functional
groups that covalently bond to regions of the substrate having
first chemical characteristics.
[0030] Other and further objects, advantages and features of the
present invention will be understood by reference to the following
specification in conjunction with the annexed drawings, wherein
like parts have been given like numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a general process flow chart for self aligned mask
generation by covalent polymer attachment, in accordance with the
invention.
[0032] FIG. 2 illustrates a first method for self aligned mask
generation by polymer reaction, in accordance with the
invention.
[0033] FIG. 3 is a general process flow chart for self aligned mask
generation by surface polymerization, in accordance with the
invention.
[0034] FIG. 4 is a second method for self aligned mask generation
by chain polymerization from a surface grafted initiator, in
accordance with the invention.
[0035] FIG. 5 is a third method for self aligned mask generation by
chain polymerization from a surface grafted monomer, in accordance
with the invention.
[0036] FIG. 6 is a fourth method for self-aligned mask generation
by step polymerization from a surface grafted reactive site, in
accordance with the invention.
[0037] FIG. 7 is a cross sectional view of a semiconductor device
in accordance with the invention.
[0038] FIG. 8 is a cross sectional view of another semiconductor
device in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] In accordance with the invention, a patterned substrate
containing structures having two or more distinct components is
processed by a route whereby layers can be applied to selected
component surfaces. This layer can be generated by a number of
approaches involving selective reactions described below and can be
used as a mask layer for subsequent treatment or material
deposition onto the intended component surfaces. These structures
can be sacrificial and do not generally remain in the final
structure. The use of the masks for the generation of self
assembled barrier layers can proceed by a number of routes
including: blanket deposition followed by lift-off, blanket
deposition followed by chemical mechanical polishing (CMP), and
enhancement of selective electrochemical and electroless metal
deposition processes. It will be clear to one skilled in the art
that the application of a self-aligned layer by any of the
approaches described below can be used as a process to generate a
selective mask.
[0040] Two general approaches exist for the self-aligned mask
generation. The preferred embodiment of the patterned substrate is
an interconnect structure having metal 20 and dielectric surfaces
10, as described below.
[0041] Referring to FIGS. 1 and 2, the process flow and process for
a first method, in accordance with the invention, for pattern
self-replication are illustrated, respectively. A polymer
containing at least one reactive grafting site is prepared at step
2, generally in a carrier such as a solvent. The reactive grafting
site is a functional group that forms at least one covalent bond
with the dielectric surface. In some cases, the surface of the
patterned substrate may be modified, at step 3, to enhance
preferential surface reaction in some regions of the patterned
substrate. At step 4, the polymer 100, which contains a reactive
grafting site A, that selectively binds to the dielectric surface
10 through the formation of at least one covalent bond is spin
coated or applied by any suitable coating method to the substrate
containing the patterned substrate. Either upon contact or with
appropriate treatment, e.g., thermal annealing or inducing reaction
by radiation, as at step 5, the polymer 100 containing the reactive
grafting site A reacts or interacts favorably with the intended
surface. Removal of the material at step 6, e.g., rinsing with
solvent, can then be performed to remove unbound material that may
be remaining on the metal surface 20 resulting in a self-aligned
mask layer located solely on the dielectric surface 10.
[0042] Optionally, the surface characteristics of one or more of
the exposed surfaces can be chemically modified prior to
application of the self-aligned mask layer to facilitate each of
the methods described above in step 3. Either the dielectric
surface 10 or the metal surface 20 can be modified in this step.
Chemical modification can be performed with any combination of
modification schemes including: plasma treatment, application of an
oxidizing or reducing solution, annealing in a reducing or
oxidizing atmosphere, and application of a material that renders
surface portions of the substrate, to which it is applied, to be
hydrophobic or hydrophilic. Specific chemical treatments directed
to the dielectric surface 10 may include applying an organosilane
comprised of Si.sub.xL.sub.yR.sub.z, where L is selected from the
group consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy,
carboxy, amines, halogens, R is selected from the group consisting
of hydrido, methyl, ethyl, vinyl, and phenyl (any alkyl or aryl).
Specific chemical treatments directed to the metal surface 20 may
include applying molecules that have preferential interactions with
the metal surface including molecules having the following
functional groups: hydroxys, esters, ethers, aldehydes, ketones,
carbonates, acids, phenols, amines, amides, imides, thioesters,
thioethers, ureas, urethanes, nitriles, isocyanates, thiols,
sulfones, halides, phosphines, phosphine oxides, phosphonimides,
nitros, azos, thioesters, thioethers, benzotriazole, pyridines,
imidazoles, imides, oxazoles, benzoxazoles, thiazoles, pyrazoles,
triazoles, thiophenes, oxadiazoles, thiazines, thiazoles,
quionoxalines, benzimidazoles, oxindoles, indolines, nitrogenous
compounds, ans phosphoric acids.
[0043] In this first method, the polymer 100 containing a reactive
grafting site A can be_amorphous, may have any chain architecture
(including linear, networked, branched, dendrimeric), and can
contain one or more monomeric units. The polymer may have acyclic
main chains (carbon containing backbones) and may include
poly(dienes), poly(alkenes), poly(acrylics), poly(methacrylics),
poly(acrylamides), poly(methacrylamides), poly(vinylethers),
poly(vinyl alcohols), poly(ketones), poly(acetals),
poly(vinylesters), poly(vinylhalides), poly(vinylnitriles),
poly(styrenes), poly(vinyl pyridines), poly(vinyl pyrrolidones),
poly(vinyl imidazoles), and poly(vinylheterocyclics). If the
polymer has a carbocyclic main chain, it may be, for example, a
poly(phenylene). The polymer may also be a main chain acyclic
heteroatom polymer selected from the group of poly(oxides),
poly(carbonates), poly(esters), poly(anhydrides), poly(urethanes),
poly(sulfonates), poly(siloxanes), poly(sulfides),
poly(thioethers), poly(thioesters), poly(sulfones),
poly(sufonamides), poly(amides), poly(imines), poly(ureas),
poly(phosphazenes), poly(silanes), poly(siloxanes),
poly(silazanes), and poly(nitriles). The polymer may have a
heterocyclic main chain and may be selected from the group of
poly(imides), poly(oxazoles), poly(benzoxazoles), poly(thiazoles),
poly(pyrazoles), poly(triazoles), poly(thiophenes),
poly(oxadiazoles), poly(thiazines), poly(thiazoles),
poly(quionoxalines), poly(benzimidazoles), poly(oxindoles),
poly(indolines), poly(pyridines) poly(triazines),
poly(piperazines), poly(pyridines), poly(piperdines),
poly(pyrrolidines), poly(carboranes), poly(fluoresceins),
poly(acetals), and poly(anhydrides).
[0044] The materials are designed with reactive functional groups
A, or reactive grafting sites which may be selected from the group
consisting: acyl chlorides, anhydrides, hydroxys, esters, ethers,
aldehydes, ketones, carbonates, acids, epoxies, aziridines,
phenols, amines, amides, imides, isocyanates, thiols, sulfones,
halides, phosphines, phosphine oxides, nitros, azos, benzophenones,
acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, and phenyl (any alkyl or aryl), that
covalently bind to the dielectric surface 10. These film structures
can then be used as a mask for further processing as described
previously.
[0045] Referring to FIG. 3, the process flow for the second, third,
and fourth methods for pattern self-replication, in accordance with
the invention, is illustrated. Also referring to FIGS. 4-6, but
first to FIG. 3, the second, third, and fourth methods use a
material that selectively reacts with the dielectric surface 10 and
is subsequently used to generate a mask layer through
polymerization of a monomer or telomer system. Optionally, the
chemical modification of either the dielectric surface 10 or metal
surface 20, as described previously, can be first performed at step
11. This method involves, at step 12, a covalent anchoring of a
reactive molecule onto the dielectric surface 10 followed by a
reaction, at step 14, with a polymerizable group (monomer,
macromonmer, telomer) to generate a self aligned mask layer 500.
Optional steps include rinsing with a solvent 13 between steps 12
and 14, exposure to heat or radiation at step 15, and rinsing with
a solvent at step 16, as more fully described below.
[0046] Both the second and third methods involve a chain growth
mechanism wherein polymerization proceeds primarily through
addition of monomer to a reactive polymer. For either of these
methods, the chemical modification of either the dielectric surface
10 or metal surface 20, as described previously, can be first
performed.
[0047] Referring to FIG. 4, the second method involves
polymerization from a substrate grafted initiator. If the reactive
molecule has a moiety that can serve as a polymerization initiator
I, attachment of the reactive molecule to the dielectric surface 10
generates a layer having functional groups suitable for
polymerization initiation 200. Application of reactive monomer to
the layer having functional groups suitable for polymerization
initiation 200 results in a self aligned mask layer 500 through
polymerization from the surface.
[0048] For the second method, the reactive molecule is comprised of
a first moiety that will bind the reactive molecule to the
dielectric surface 10 and a second moiety that will serve as a
polymerization initiator. The first moiety allowing covalent
bonding to the dielectric surface may include reactive grafting
sites, selected from the group including acyl chlorides,
anhydrides, hydroxys, esters, ethers, aldehydes, ketones,
carbonates, acids, epoxies, aziridines, phenols, amines, amides,
imides, isocyanates, thiols, sulfones, halides, phosphines,
phosphine oxides, nitros, azos, benzophenones, acetals, ketals,
diketones, and organosilanes (Si.sub.xL.sub.yR.sub.z,) where L is
selected from the group consisting of hydroxy, methoxy, ethoxy,
acetoxy, alkoxy, carboxy, amines, halogens, R is selected from the
group consisting of hydrido, methyl, ethyl, vinyl, and phenyl (any
alkyl or aryl). The second moiety serving as a polymerization
initiator may include, peroxides, nitroxides, halides, azos,
peresters, thioesters, hydroxy; metal organics having the
stoichiometry of RX where R may consist of: benzyl, cumyl, butyl,
alkyl, napthalene, and X may consist of sodium, lithium, and
potassium; protonic acids, lewis acids, carbenium salts, tosylates,
triflates, benzophenones, aryldiazonium, diaryliodonium,
triarylsulfonium, acetals, ketals, and diketones. The reactive
monomer can be any substituted ethylenic organic molecule or
monomeric ring that polymerizes under a number of conditions (free
radical, anionic, cationic, etc.) and can include: dienes, alkenes,
acrylics, methacrylics, acrylamides, methacrylamides, vinylethers,
vinyl alcohols, ketones, acetals, vinylesters, vinylhalides,
vinylnitriles, styrenes, vinyl pyridines, vinyl pyrrolidones, vinyl
imidazoles, vinylheterocyclics, styrene, cyclic lactams, cyclic
ethers, cyclic lactones, cycloalkenes, cyclic thioesters, cyclic
thioethers, aziridines, phosphozines, siloxanes, oxazolines,
oxazines, and thiiranes.
[0049] Referring to FIG. 5, a third method, in accordance with the
invention, involves polymerization from a substrate grafted
monomer. If the reactive molecule is a moiety that can serve as a
polymerizable monomer M, attachment of the reactive molecule to the
dielectric surface 10 generates a layer 300 having functional
groups suitable for polymerization propagation. Application of a
reactive monomer to the layer having functional groups suitable for
polymerization propagation 300 results in a self aligned mask layer
500 through polymerization from the surface.
[0050] For the third method, in accordance with the invention, the
reactive molecule is comprised of a first moiety that will bind the
reactive molecule to the dielectric surface 10 and a second moiety
that will serve as a monomeric unit. The first moiety allowing
covalent bonding to the dielectric surface can include reactive
grafting sites such as acyl chlorides, anhydrides, hydroxys,
esters, ethers, aldehydes, ketones, carbonates, acids, epoxies,
aziridines, phenols, amines, amides, imides, isocyanates, thiols,
sulfones, halides, phosphines, phosphine oxides, nitros, azos,
benzophenones, acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, and vinyl, phenyl (any alkyl or aryl). The
second moiety serving as a monomeric unit can include, dienes,
alkenes, acrylics, methacrylics, acrylamides, methacrylamides,
vinylethers, vinyl alcohols, ketones, acetals, vinylesters,
vinylhalides, vinylnitriles, styrenes, vinyl pyridines, vinyl
pyrrolidones, vinyl imidazoles, vinylheterocyclics, styrene, cyclic
lactams, cyclic ethers, cyclic lactones, cycloalkenes, cyclic
thioesters, cyclic thioethers, aziridines, phosphozines, siloxanes,
oxazolines, oxazines, and thiiranes. The reactive monomer can be
any vinyl or monomeric ring as described for the second method.
[0051] Referring to FIG. 6, a fourth method, in accordance with the
invention, involves a step growth mechanism, whereby polymerization
proceeds by reactions that combine monomers and polymers having two
or more functionalities that react with each other to produce
polymers of larger molecular weight. For this method, the chemical
modification of either the dielectric surface 10 or metal surface
20, as described previously, can be first performed. This approach,
as shown in FIG. 6, utilizes a polymerization scheme where the
reactive molecule, having a functional group R, is applied to the
patterned substrate. Selective reaction of the reactive molecule to
the dielectric surfaces 10 generates a layer 400 having reactive
groups, which can participate in step growth polymerizations.
Application of reactive monomers, having either one or more S
and/or T functionalities that react with each other to form a
covalent bond, to the layer having reactive groups 400, results in
the formation of a self aligned mask layer 500.
[0052] For the fourth method, the masking material is comprised of
a first moiety that will bind the reactive molecule to the
dielectric surface 10 and a second moiety that will serve as a
reaction site. The first moiety allowing covalent bonding to the
dielectric surface can include, organosilanes, hydroxy, acyl
chlorides, carboxylic acids acyl chlorides, anhydrides, hydroxys,
esters, ethers, aldehydes, ketones, carbonates, acids, epoxies,
aziridines, phenols, amines, amides, imides, isocyanates, thiols,
sulfones, halides, phosphines, phosphine oxides, nitros, azos,
benzophenones, acetals, ketals, diketones, and organosilanes
(Si.sub.xL.sub.yR.sub.z,) where L is selected from the group
consisting of hydroxy, methoxy, ethoxy, acetoxy, alkoxy, carboxy,
amines, halogens, R is selected from the group consisting of
hydrido, methyl, ethyl, vinyl, and phenyl (any alkyl or aryl). The
second moiety serving as a monomeric unit can include, amines,
nitriles, alcohols, carboxylic acids, sulfonic acids, isocyanates,
acyl chlorides, esters, amides, anhydrides, epoxies, halides,
acetoxy, vinyl, and silanols. Monomers used for this approach are
molecules having two or more chemically identical or dissimilar
functional groups that undergo step growth polymerization. The
functional groups can include: amines, nitriles, alcohols,
carboxylic acids, sulfonic acids, isocyanates, acyl chlorides,
esters, amides, anhydrides, epoxies, halides, acetoxy, vinyl, and
silanols.
[0053] Use of the Above Methods in Fabricating IC Chips, Chip
Carriers and Circuit Boards
[0054] Several derived structures can be fabricated using the
selective masking methods described above. In these examples, the
pre-existence of a substrate containing a pattern, the pattern
comprised of a first set of regions of the substrate surface having
a first atomic composition including one or more metal elements and
having a second set of regions of the substrate surface being a
dielectric and having a second atomic composition different from
the first composition, is presumed. Selective blocking of the
dielectric surface is achieved first by one of the methods
described above. The first set of regions or areas which comprises
one or metal elements is exposed and is then subjected to
processing steps such as electroless deposition alone, or
electoless deposition of metal, metal or dielectric deposition by
sputtering, evaporation, chemical vapor deposition (CVD), plasma
enhanced chemical vapor deposition (PECVD) and the like, followed
by an optional planarization step to form added layers only on the
first set of regions.
[0055] The structure which is produced is a microelectronic
interconnect structure comprising at least one conductive feature
with a selective cap on its top surface, formed on a substrate,
with the substrate further comprising at least one insulating layer
surrounding the conductive feature at its bottom and lateral
surfaces, and one or more optional conductive barrier layers
disposed at one or more of the interfaces between the insulator and
the conductive feature.
[0056] Examples of this structural embodiment include, but are not
limited to, electrically conductive interconnect wiring which is
capped and embedded in a device chip interconnect stack containing
insulators, conducting and insulating barrier layers and the like;
interconnect wiring of metals disposed on a ceramic chip carrier
package; and interconnect wiring disposed on and within an organic
chip or device carrier such as a printed circuit board; and thin
film wiring arrays on a glass or polymeric substrate used in the
fabrication of information displays and related hand held
devices.
[0057] Referring to FIG. 7, an interconnect structure 30 having an
interlayer dielectric 31, metal wiring 32,, liner barrier layer 34,
and cap barrier layer 36 is illustrated. The interconnect structure
has multiple levels 1000 comprised of via 1100 and line 1200
levels. The preferred materials for the interlayer dielectric 31
have low dielectric constants (k<3) and include: carbon-doped
silicon dioxide (also known as silicon oxycarbide or SiCOH
dielectrics); fluorine-doped silicon oxide (also known as
fluorosilicate glass, or FSG); spin-on glasses; silsesquioxanes,
including hydrogen silsesquioxane (HSSQ), methyl silsesquioxane
(MSSQ) and mixtures or copolymers of HSSQ and MSSQ; and any
silicon-containing low-k dielectric. As would be known in the art,
this interlayer dielectric may contain pores to further reduce the
dielectric constant, and other dielectrics may be used.
[0058] Referring to FIG. 8, an interconnect structure 40 having an
interlayer dielectric 31, dielectric hardmask 41, metal wiring 32,
, liner barrier layer 34, and cap barrier layer 36 is illustrated.
The interconnect structure has multiple levels 1000 comprised of
via 1100 and line 1200 levels. The preferred materials for the
interlayer dielectric 31 have low dielectric constants (k<3),
may be an organic polymer thermoset, and may be selected from the
group SiLK.TM., (a product of Dow Chemical Co. ), Flare.TM. (a
product of Honeywell), and other polyarylene ethers . As would be
known in the art, this organic polymer dielectric may contain pores
to further reduce the dielectric constant, and other organic
polymer thermoset dielectrics may be used. The preferred materials
for the dielectric hardmask 41 include: silicon carbides,
carbon-doped silicon dioxide (also known as silicon oxycarbide or
SiCOH dielectrics); fluorine-doped silicon oxide (also known as
fluorosilicate glass, or FSG); spin-on glasses; silsesquioxanes,
including hydrogen silsesquioxane (HSQ), methyl silsesquioxane
(MSQ) and mixtures or copolymers of HSQ and MSQ; and any
silicon-containing dielectric.
[0059] Applications of the inventive methods to form selective cap
barrier layers 36 on patterned metal interconnects are now
described in reference to the structures shown in FIGS. 7 and 8
which may be produced using any of the methods described herein.
The structures may be generated through a series of steps known in
the art involving photolithography; dielectric deposition by spin
coating or chemical vapor deposition; metal deposition by
electroplating, electoless plating, thermal evaporation,
sputtering; planarization by chemical mechanical polishing; wet and
dry etch processes such as reactive ion etching; thermal anneals;
wet and dry cleans, etc. The example given includes specific
details, but it is evident that numerous alternatives,
modifications and variations will be apparent to those skilled in
the art in light of the methods descriptions given above. Various
materials may form the selective cap (such as silicon nitride, or
various refractory metals and compounds of said metals). Further,
this invention is not limited to constructions of any particular
shape or composition.
[0060] The application of the methods described herein may be
utilized after chemical mechanical polishing steps that result in a
patterned top surface as shown in FIGS. 2, 4, 5, and 6. A preferred
route to produce a self aligned mask may be to apply polystyrene
(PS) having silanol reactive groups, from a toluene solution that
would be applied to the patterned surface as shown in FIG. 2 by
spin coating. The silanol groups would then covalently bind to the
dielectric surfaces with thermal annealing when the wafer is placed
on a hot plate at a temperature of about 150.degree. C. for 1 to 5
minutes, in an inert (N.sub.2) atmosphere. Removal of unbound PS,
by rinsing with toluene, from the metal regions generates a
topography, with PS remaining on the dielectric regions.
[0061] In the next step, this polystyrene is used as the self
aligned mask. A bilayer of tantalum nitride (TaN) and tantalum is
then deposited by sputtering in a sputter deposition tool (known in
the art) on the patterned substrate containing the self aligned
mask. The TaN/Ta bilayer contacts the metal regions and conformally
coats the PS. The wafer is then placed in a chemical mechanical
polishing (CMP) tool and the bilayer is removed from the
polystyrene, and is left intact on the metal regions. Removal of
the remaining polystyrene is then performed using thermal
degradation by heating in an inert ambient containing <10 ppm
O.sub.2 or H.sub.2O at a temperature of 400.degree. C. for 30
minutes, to leave the selective cap barrier layer 36 comprised of
TaN and Ta only on the metal regions.
[0062] While we have shown and described several embodiments in
accordance with our invention, it is to be clearly understood that
the same are susceptible to numerous changes apparent to one
skilled in the art. Therefore, we do not wish to be limited to the
details shown and described but intend to show all changes and
modifications which come within the scope of the appended
claims.
* * * * *