U.S. patent application number 11/083874 was filed with the patent office on 2005-07-28 for integrated circuit devices having a metal-insulator-metal (mim) capacitor.
Invention is credited to Jeong, Yong-kuk, Joo, Jae-hyun, Kim, Wan-don, Yoo, Cha-young.
Application Number | 20050161727 11/083874 |
Document ID | / |
Family ID | 19710240 |
Filed Date | 2005-07-28 |
United States Patent
Application |
20050161727 |
Kind Code |
A1 |
Joo, Jae-hyun ; et
al. |
July 28, 2005 |
Integrated circuit devices having a metal-insulator-metal (MIM)
capacitor
Abstract
In some embodiments, an integrated circuit device includes a
substrate and an interlevel-insulating layer on the substrate that
has a hole therein that exposes the substrate. A unitary lower
electrode of a capacitor is disposed on the substrate and has a
contact plug portion thereof that is disposed in the hole. A
dielectric layer is on the lower electrode and an upper electrode
of the capacitor is on the dielectric layer. In other embodiments,
an integrated circuit device includes a substrate and an
interlevel-insulating layer on the substrate that has a hole
therein that exposes the substrate. A barrier layer is disposed on
the exposed portion of the substrate and on sidewalls of the
interlevel-insulating layer. A contact plug is disposed in the hole
on the barrier layer. A lower electrode of a capacitor is disposed
on the contact plug and engages the contact plug at a boundary
therebetween. A dielectric layer is on the lower electrode and an
upper electrode of the capacitor is on the dielectric layer.
Inventors: |
Joo, Jae-hyun; (Seoul,
KR) ; Yoo, Cha-young; (Suwon-city, KR) ; Kim,
Wan-don; (Kyungki-do, KR) ; Jeong, Yong-kuk;
(Seoul, KR) |
Correspondence
Address: |
MYERS BIGEL SIBLEY & SAJOVEC
PO BOX 37428
RALEIGH
NC
27627
US
|
Family ID: |
19710240 |
Appl. No.: |
11/083874 |
Filed: |
March 18, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11083874 |
Mar 18, 2005 |
|
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|
10160646 |
May 31, 2002 |
|
|
|
6884673 |
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Current U.S.
Class: |
257/309 ;
257/308; 257/E21.011; 257/E21.019; 257/E21.649; 438/255;
438/399 |
Current CPC
Class: |
H01L 28/91 20130101;
H01L 28/60 20130101; H01L 27/10855 20130101 |
Class at
Publication: |
257/309 ;
438/255; 257/308; 438/399 |
International
Class: |
H01L 029/76; H01L
021/20 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2001 |
KR |
2001-0030529 |
Claims
1. An integrated circuit device, comprising: a substrate; an
interlevel-insulating layer on the substrate having a hole therein
that exposes the substrate; a unitary lower electrode of a
capacitor disposed on the substrate that has a contact plug portion
thereof that is disposed in the hole; a dielectric layer on the
lower electrode of the capacitor; and an upper electrode of the
capacitor on the dielectric layer.
2. The integrated circuit device of claim 1, further comprising: a
barrier layer between the contact plug portion of the lower
electrode of the capacitor and both the substrate and sidewalls of
the interlevel-insulating layer.
3. The integrated circuit device of claim 2, wherein the barrier
layer has a thickness in a range of about 30 .ANG. to about 300
.ANG..
4. The integrated circuit device of claim 2, wherein the barrier
layer comprises a material that is selected from the group of
materials consisting of TiN, TiSiN, TiAlN, TaN, TaSiN, and
TaAlN.
5. The integrated circuit device of claim 2, wherein the lower
electrode of the capacitor is cylindrical.
6. The integrated circuit device of claim 5, wherein the barrier
layer has a thickness in a range of about 30 .ANG. to about 300
.ANG..
7. The integrated circuit device of claim 1, further comprising: a
mold layer on the interlevel-insulating layer that has an opening
therein through which the lower electrode of the capacitor is
received.
8. The integrated circuit device of claim 7, wherein the mold layer
comprises silicon oxide.
9. The integrated circuit device of claim 7, further comprising: an
etch stop layer on the mold layer that has an opening therein
through which the lower electrode of the capacitor is received.
10. The integrated circuit device of claim 9, wherein the etch stop
layer comprises a material selected from the group of materials
consisting of silicon oxide, and tantalum oxide.
11. The integrated circuit device of claim 1, wherein the
dielectric layer comprises a material selected from the group of
materials consisting of Al.sub.2O.sub.3, Ta.sub.2O.sub.5, TiO, (Ba,
Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, and (Pb, La)(Zr, Ti)O.sub.3.
12. The integrated circuit device of claim 1, wherein the upper and
lower electrodes of the capacitor comprise a material selected from
the group of materials consisting of Pt, Ru, and Ir.
13. An integrated circuit device, comprising: a substrate; an
interlevel-insulating layer on the substrate having a hole therein
that exposes the substrate; a barrier layer on the exposed portion
of the substrate and on sidewalls of the interlevel-insulating
layer; a contact plug disposed in the hole on the barrier layer; a
lower electrode of a capacitor disposed on the contact plug and
that engages the contact plug at a boundary therebetween; a
dielectric layer on the lower electrode of the capacitor; and an
upper electrode of the capacitor on the dielectric layer.
14. The integrated circuit device of claim 13, wherein the barrier
layer has a thickness in a range of about 30 .ANG. to about 300
.ANG..
15. The integrated circuit device of claim 13, wherein the barrier
layer comprises a material that is selected from the group of
materials consisting of TiN, TiSiN, TiAlN, TaN, TaSiN, and
TaAlN.
16. The integrated circuit device of claim 13, wherein the lower
electrode of the capacitor is cylindrical.
17. The integrated circuit device of claim 16, wherein the barrier
layer has a thickness in a range of about 30 .ANG. to about 300
.ANG..
18. The integrated circuit device of claim 13, further comprising:
a mold layer on the interlevel-insulating layer that has an opening
therein through which the lower electrode of the capacitor is
received.
19. The integrated circuit device of claim 18, wherein the mold
layer comprises silicon oxide.
20. The integrated circuit device of claim 18, further comprising:
an etch stop layer on the mold layer that has an opening therein
through which the lower electrode of the capacitor is received.
21. The integrated circuit device of claim 20, wherein the etch
stop layer comprises a material selected from the group of
materials consisting of silicon oxide, and tantalum oxide.
22. The integrated circuit device of claim 13, wherein the
dielectric layer comprises a material selected from the group of
materials consisting of Al.sub.2O.sub.3, Ta.sub.2O.sub.5, TiO, (Ba,
Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, and (Pb, La)(Zr, Ti)O.sub.3.
23. The integrated circuit device of claim 13, wherein the upper
and lower electrodes of the capacitor and the contact plug comprise
a material selected from the group of materials consisting of Pt,
Ru, and Ir.
24-38. (canceled)
Description
RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 2001-0030529, filed May 31, 2001, the disclosure of
which is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to integrated
circuit devices, and, more particularly, to integrated circuit
capacitors and methods of forming same.
BACKGROUND OF THE INVENTION
[0003] In general, as the integration density of integrated circuit
devices increases, conventional metal-insulator-semiconductor (MIS)
capacitors may have relatively low dielectrics so that they may not
provide desired capacitance values. As a result,
metal-insulator-metal (MIM) capacitors may be used to replace MIS
capacitors.
[0004] FIG. 1 is a cross-sectional view of a conventional
integrated circuit device that comprises a MIM capacitor. As shown
in FIG. 1, a contact plug 15 is formed in an interlevel-insulating
layer 13 on a substrate 11, e.g., a silicon substrate. The contact
plug 15 may comprise a TiN layer and may be used as a barrier
layer. A MIM capacitor 23 is formed on the contact plug 15. The
contact plug 15 may connect the MIM capacitor 23 to a driving
transistor (not shown) allowing charges to accumulate on the MIM
capacitor 23 or be discharged from the MIM capacitor 23. The MIM
capacitor 23 comprises a lower electrode 17, a dielectric layer 19,
and an upper electrode 21. The lower electrode 17 and the upper
electrode 21 may comprise a metal, such as Pt or Ru, and the
dielectric layer 19 may comprise Ta.sub.2O.sub.5.
[0005] Unfortunately, cracks may occur in the interlevel-insulating
layer 13 due to stress generated during the deposition of the TiN
layer, i.e., the contact plug 15. Also, due to generally poor step
coverage of the TiN layer, a seam may occur in the TiN layer if the
TiN layer is deposited and then planarized by chemical mechanical
polishing (CMP).
SUMMARY OF THE INVENTION
[0006] According to some embodiments of the present invention, an
integrated circuit device comprises a substrate and an
interlevel-insulating layer on the substrate that has a hole
therein that exposes the substrate. A unitary lower electrode of a
capacitor is disposed on the substrate and has a contact plug
portion thereof that is disposed in the hole. A dielectric layer is
on the lower electrode and an upper electrode of the capacitor is
on the dielectric layer. Because the lower electrode and the
contact plug comprise a unitary body, cracks in the
interlevel-insulating layer may be reduced and a seam may not be
created in the contact plug.
[0007] In other embodiments of the present invention, a barrier
layer is disposed between the contact portion of the lower
electrode and both the substrate and sidewalls of the
interlevel-insulating layer. The barrier layer may comprise TiN,
TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or alloys thereof, and may
have a thickness in a range of about 30 .ANG. to about 300
.ANG..
[0008] In still other embodiments, the lower electrode of the
capacitor is cylindrical and the barrier layer has a thickness in a
range of about 30 .ANG. to about 300 .ANG..
[0009] In further embodiments of the present invention, a mold
layer, which may comprise silicon oxide, is on the
interlevel-insulating layer that has an opening therein through
which the lower electrode of the capacitor is received. An etch
stop layer may also be on the mold layer and have an opening
therein through which the lower electrode of the capacitor is
received. The etch stop layer may comprise silicon oxide and/or
tantalum oxide.
[0010] In still further embodiments, the dielectric layer may
comprise may comprise Al.sub.2O.sub.3, Ta.sub.2O.sub.5, TiO, (Ba,
Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, (Pb, La)(Zr, Ti)O.sub.3, and/or
alloys thereof and the upper and lower electrodes of the capacitor
may comprise one or more platinum group metals, such as Pt, Ru, and
Ir.
[0011] In other embodiments of the present invention, an integrated
circuit device comprises a substrate and an interlevel-insulating
layer on the substrate that has a hole therein that exposes the
substrate. A barrier layer is disposed on the exposed portion of
the substrate and on sidewalls of the interlevel-insulating layer.
A contact plug is disposed in the hole on the barrier layer. A
lower electrode of a capacitor is disposed on the contact plug and
engages the contact plug at a boundary therebetween. A dielectric
layer is on the lower electrode and an upper electrode of the
capacitor is on the dielectric layer. Advantageously, the barrier
layer may increase adhesion with the contact plug and may also
reduce contact resistance. In particular embodiments, the barrier
layer may comprise TiN, TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or
alloys thereof, and may have a thickness in a range of about 30
.ANG. to about 300 .ANG..
[0012] Although described above primarily with respect to device
embodiments, the present invention may also be embodied as methods
of forming integrated circuit devices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other features of the present invention will be more readily
understood from the following detailed description of specific
embodiments thereof when read in conjunction with the accompanying
drawings, in which:
[0014] FIG. 1 is a cross-sectional view of a conventional
integrated circuit device that includes a metal-insulator-metal
(MIM) capacitor; and
[0015] FIGS. 2-9 are cross sectional views that illustrate
integrated circuit devices that comprise a MIM capacitor and
methods of forming same in accordance with various embodiments of
the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0016] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof are shown by
way of example in the drawings and will herein be described in
detail. It should be understood, however, that there is no intent
to limit the invention to the particular forms disclosed, but on
the contrary, the invention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the invention as defined by the claims. Like numbers refer to
like elements throughout the description of the figures. In the
figures, the dimensions of layers and regions are exaggerated for
clarity. It will also be understood that when an element, such as a
layer, region, or substrate, is referred to as being "on" another
element, it can be directly on the other element or intervening
elements may be present. In contrast, when an element, such as a
layer, region, or substrate, is referred to as being "directly on"
another element, there are no intervening elements present.
[0017] FIG. 2 is a cross-sectional view that illustrates integrated
circuit devices having a MIM capacitor according to some
embodiments of the present invention. As shown in FIG. 2, an
interlevel-insulating layer 103 is disposed on, for example, a
silicon substrate 101 and has a contact hole 105 formed therein
that exposes a portion of the substrate 101. The
interlevel-insulating layer 103 may comprise silicon oxide. A
barrier layer 107 is formed along the sidewalls and bottom of the
contact hole 105 to fill a portion thereof. The barrier layer 107
may be used to increase adhesion between the barrier layer 107 and
a contact plug 119a, which will be subsequently formed, and to
lower contact resistance. The barrier layer 107 may comprise TiN,
TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or alloys thereof, and may
have a thickness in a range of about 30 .ANG. to about 300
.ANG..
[0018] A contact plug 119a comprising a metal is disposed in the
contact hole 105. Moreover, a lower electrode 119b extends from the
contact plug 119a and the contact hole 105. Thus, the contact plug
119a and the lower electrode 119b comprise a unitary body. The
contact plug 119a and the lower electrode 119b may comprise one or
more platinum group metals, such as Pt, Ru, and/or Ir. The lower
electrode 119b may be viewed as a stack type electrode.
Advantageously, the contact plug 119a filling the contact hole 105
comprises the same metal as the lower electrode 119b, instead of,
for example, TiN. As a result, cracks in the interlevel-insulating
layer 103 may be reduced, and a seam may not be created in the
contact plug 119a.
[0019] A lower mold layer pattern 111a and a wet etch stop pattern
113a are formed on the interlevel-insulating layer 103 and at both
sides of the lower electrode 119b. The lower mold layer pattern
111a may provide enhanced stability in forming the lower electrode
119b. The wet etch stop pattern 113a may protect the lower mold
layer pattern 111a and/or the interlevel-insulating layer 103
during manufacturing processing of the capacitor.
[0020] A dielectric layer 121 is formed on the lower electrode
119b. The dielectric layer 121 may comprise Al.sub.2O.sub.3,
Ta.sub.2O.sub.5, TiO, (Ba, Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, (Pb,
La)(Zr, Ti)O.sub.3, and/or alloys thereof. An upper electrode 123
is formed on the dielectric layer 121. The upper electrode 123 may
comprise one or more platinum group metals, such as Pt, Ru, and/or
Ir. Thus, a MIM capacitor, according to some embodiments of the
present invention, comprises the lower electrode 119b, the
dielectric layer 121, and the upper electrode 123. The contact plug
119a may connect the MIM capacitor to a driving transistor (not
shown) allowing charges to accumulate on the MIM capacitor or be
discharged from the MIM capacitor.
[0021] FIG. 3 is a cross-sectional view that illustrates integrated
circuit devices having a MIM capacitor according to further
embodiments of the present invention. Embodiments of integrated
circuit devices illustrated in FIG. 3 are similar to the integrated
circuit device embodiments discussed above with respect to FIG. 2,
with the exception that a barrier layer 207, which is formed along
the sidewalls and the bottom of the contact hole 105, is thicker
than the barrier layer 107 of FIG. 2, and a lower electrode 219b of
a capacitor is cylindrical. The barrier layer 207 may comprise TiN,
TiSiN, TIAIN, TaN, TaSiN, TaAlN, and/or alloys thereof, and may
have a thickness in a range of about 30 .ANG. to about 300 .ANG..
Similar to the description above with respect to FIG. 2, a contact
plug 219a may fill the contact hole 105. A lower electrode 219b
extends from the contact plug 219a and the contact hole 105.
Because the lower electrode 219b of the MIM capacitor is
cylindrical, the capacitance may be increased.
[0022] FIG. 4 is a cross-sectional view that illustrates integrated
circuit devices having a MIM capacitor according to further
embodiments of the present invention. Embodiments of integrated
circuit devices illustrated in FIG. 3 are similar to integrated
circuit device embodiments discussed above with respect to FIG. 2,
with the exception that the barrier layer 207, which is formed
along the sidewalls and the bottom of the contact hole 105, is
thicker than the barrier layer 107 of FIG. 2, and a contact plug
319a and a lower electrode 319b do not comprise a unitary body. The
barrier layer 207 may comprise TiN, TiSiN, TiAlN, TaN, TaSiN,
TaAlN, and/or alloys thereof, and may have a thickness in a range
of about 30 .ANG. to about 300 .ANG..
[0023] FIG. 5 is a cross-sectional view that illustrates integrated
circuit devices having a MIM capacitor according to further
embodiments of the present invention. Embodiments of integrated
circuit devices illustrated in FIG. 5 are similar to integrated
circuit device embodiments discussed above with respect to FIG. 4,
with the exception that a lower electrode 419a of the MIM capacitor
is cylindrical.
[0024] Methods of fabricating integrated circuit devices having a
MIM capacitor, in accordance with various embodiments of the
present invention, will now be described. FIGS. 6A through 6H are
cross-sectional views that illustrate operations in fabricating
integrated circuit devices having a MIM capacitor according to some
embodiments of the present invention described above with reference
to FIG. 2. Referring now to FIG. 6A, an interlevel-insulating layer
103 is formed on a substrate 101, which may comprise silicon. The
interlevel-insulating layer 103 may comprise silicon oxide. The
interlevel-insulating layer 103 is patterned by photolithography to
form a first contact hole 105. A barrier layer 107 is formed on the
surface of the semiconductor substrate 101. A barrier layer 107 is
formed along the sidewalls and bottom of the first contact hole 105
and on the interlevel-insulating layer 103 without filling the
first contact hole 105. The barrier layer 107 may comprise TiN,
TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or alloys thereof, and may
have a thickness in a range of about 30 .ANG. to about 300
.ANG..
[0025] Referring now to FIGS. 6B and 6C, a first sacrificial layer
109 is formed on the surface of the substrate 101 to fill the first
contact hole 105. In other words, the first sacrificial layer 109
fills the first contact hole 105 and is formed on the
interlevel-insulating layer 103. The first sacrificial layer 109
may be a flowable oxide layer.
[0026] The first sacrificial layer 109 is planarized using the
upper surface of the interlevel-insulating layer 103 as an etch
stop, leaving the first sacrificial layer 109 in the first contact
hole 105. The planarization of the first sacrificial layer 109 may
be performed by CMP (Chemical Mechanical Polishing). The barrier
layer 107 on the interlevel-insulating layer 103 may also etched
during planarization of the first sacrificial layer 109. In other
words, the barrier layer 107 may remain only along the sidewalls
and bottom of the first contact hole 105. Thus, a barrier layer in
one cell may be separated from a barrier layer in another cell.
[0027] Referring to FIG. 6D, a lower mold layer 111 is formed on
the first sacrificial layer 109 and the interlevel-insulating layer
103. The lower mold layer 111 may comprise silicon oxide. The lower
mold layer 111 may allow a lower electrode of the MIM capacitor to
be formed with improved stability subsequently.
[0028] A wet etch stop layer 113 is formed on the lower mold layer
111. The wet etch stop layer 113 may protect the lower mold layer
111 and/or the interlevel-insulating layer 103 from manufacturing
processes. The wet etch stop layer 113 may comprise silicon oxide,
tantalum oxide, and/or combinations thereof. An upper mold layer
115 is formed on the wet etch stop layer 113. The upper mold layer
115 may comprise silicon oxide.
[0029] Referring now to FIG. 6E, the upper mold layer 115, the wet
etch stop layer 113, and the lower mold layer 111 are patterned to
form a second contact hole 117 exposing an upper surface of the
first sacrificial layer 109. Thus, an upper mold layer pattern
115a, a wet etch stop layer pattern 113a, and a lower mold layer
pattern 111a are formed on the interlevel-insulating layer 103.
[0030] The first sacrificial layer 109 in the first contact hole
105 is removed by wet etching. Because the first sacrificial layer
109 in the first contact hole 105 is a flowable oxide layer, it may
be etched faster than the interlevel-insulating layer 103 and the
lower and upper mold layers 111 and 115. Thus, the first
sacrificial layer 109 in the first contact hole 105 may be removed
with minimal damage to the interlevel-insulating layer 103 and/or
the lower and upper mold layers 111 and 115. As a result, the
barrier layer 107 in the first contact hole 105 is exposed.
[0031] Referring now to FIG. 6F, a metal layer is formed on the
substrate in the first and second contact holes 105 and 117 and
then the metal layer is reflowed using a high thermal treatment to
form a contact plug 119a, which fills the first contact hole 105.
The formation and reflow of the metal layer using a thermal
treatment may inhibit a seam from occurring in the metal layer due
to poor step coverage when the metal layer is formed. The contact
plug 119a may comprise a platinum group metal, such as Pt, Ru,
and/or Ir.
[0032] Referring now to FIG. 6G, the second contact hole 117 is
filled with the same metal filling the first contact hole 105 to
form a lower electrode 119b of a stack type capacitor. The lower
electrode 119b may comprise a platinum group metal, such as Pt, Ru,
and/or Ir. As a result, the contact plug 119a and the lower
electrode 119b comprise a unitary body and fill the first and
second contact holes 105 and 117.
[0033] Referring to FIG. 6H, the upper mold layer pattern 115a is
removed by wet etching using the wet etch stop pattern 113a as an
etch stop. The wet etching of the upper mold layer pattern 115 may
be performed for a few tens to hundreds of seconds using an oxide
etchant, e.g., a buffered oxide etchant.
[0034] Next, as shown in FIG. 2, a dielectric layer 121 is formed
on the surface of the semiconductor substrate 101. The dielectric
layer 121 may comprise Al.sub.2O.sub.3, Ta.sub.2O.sub.5, TiO, (Ba,
Sr)TiO.sub.3, Pb(Zr, Ti)O.sub.3, and/or (Pb, La)(Zr, Ti)O.sub.3. An
upper electrode 123 comprising a metal is formed on the dielectric
layer 121 to complete an integrated circuit device having a MIM
capacitor. The upper electrode 123 may comprise a platinum group
metal, such as Pt, Ru, and/or Ir.
[0035] FIGS. 7A through 7C are cross-sectional views that
illustrate operations in fabricating integrated circuit devices
having a MIM capacitor according to some embodiments of the present
invention described above with reference to FIG. 3. Methods of
fabricating an integrated circuit device according to embodiments
of the present invention illustrated in FIG. 3 are similar to
methods of fabricating an integrated circuit device according to
embodiments of the present invention illustrated in FIG. 2, with
the exception that a barrier layer 207, which is formed along the
sidewalls and the bottom of the contact hole 105, is thicker than
the barrier layer 107 of FIG. 2, and a lower electrode 219b of a
capacitor is cylindrical. The barrier layer 207 may comprise TiN,
TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or alloys thereof, and may
have a thickness in a range of about 30 .ANG. to about 300
.ANG..
[0036] First, the operations described above with reference to
FIGS. 6A through 6E are performed. Referring now to FIG. 7A, a
metal layer 219 is formed on the substrate 101 on which the barrier
layer 207 is formed along the sidewalls and bottom of the first
contact hole 105 to fill the first contact hole 105. The metal
layer 219 is used as a contact plug and a lower electrode. The
metal layer 219 is formed along the sidewalls and bottom of the
second contact hole 117 and on the surface of the upper mold layer
pattern 115a to fill the first contact hole 105, but not the second
contact hole 117. A second sacrificial layer 223 is formed on the
substrate 101 on which the metal layer 219 is formed to fill the
second contact hole 117. The second sacrificial layer 223 may
comprise a flowable oxide.
[0037] Referning now to FIG. 7B, the second sacrificial layer 223
is patterned using the upper mold layer pattern 115a as an etch
stop to leave the second sacrificial layer 223 only in the second
contact hole 117. The metal layer 219 on the upper mold layer
pattern 115a is etched and the second sacrificial layer 223 is
planarized using CMP. As a result, a contact plug 219a is formed
that fills the first contact hole 105, and a lower electrode 219b
of a capacitor having a cylindrical shape is formed along the
sidewalls and bottom of the second contact hole 117.
[0038] Referring now to FIG. 7C, the second sacrificial layer 223
left in the second contact hole 117 is removed. The upper mold
layer pattern 115 is removed using the wet etch stop pattern 111a
as an etch stop. Because the second sacrificial layer 223 left in
the second contact hole 117 comprises a flowable oxide, the upper
mold layer pattern 115a and the second sacrificial layer 223 may be
simultaneously etched.
[0039] As shown in FIG. 3, a dielectric layer 121 and an upper
electrode 123 are formed on the substrate 101 on which the lower
electrode 219b is formed, thereby completing a semiconductor device
having a MIM capacitor.
[0040] FIGS. 8A through 8F are cross-sectional views that
illustrate operations in fabricating integrated circuit devices
having a MIM capacitor according to some embodiments of the present
invention described above with reference to FIG. 4. Methods of
fabricating an integrated circuit device according to embodiments
of the present invention illustrated in FIG. 4 are similar to
methods of fabricating an integrated circuit device according to
embodiments of the present invention illustrated in FIG. 2, with
the exception that the barrier layer 207, which is formed along the
sidewalls and the bottom of the contact hole 105, is thicker than
the barrier layer 107 of FIG. 2, and a contact plug 319a and a
lower electrode 319b do not comprise a unitary body.
[0041] Referring now to FIG. 8A, an interlevel-insulating layer 103
is formed on a semiconductor substrate 101, which may comprise
silicon. The interlevel-insulating layer 103 may comprise silicon
oxide. The interlevel-insulating layer 103 is patterned by
photolithography to form a first contact hole 105.
[0042] A barrier layer 207 is formed on the semiconductor substrate
101 in which the first contact hole 105 is formed. The barrier
layer 207, which is thicker than the barrier layer 107 shown in
FIG. 6A, is formed along the sidewalls and bottom of the first
contact hole 105 and on the interlevel-insulating layer 103 without
filling the first contact hole 105. The barrier layer 207 may
comprise TiN, TiSiN, TiAlN, TaN, TaSiN, TaAlN, and/or alloys
thereof, and may have a thickness in a range of about 30 .ANG. to
about 300 .ANG.. A metal layer 319 for a contact plug is formed on
the surface of the semiconductor substrate to fill the first
contact hole 105. The metal layer 319 for a contact plug may
comprise a platinum group metal, such as Pt, Ru, and/or Ir.
[0043] Referring now to FIG. 8B, the metal layer 0.319 for a
contact plug and the barrier layer 207 are planarized using the
interlevel-insulating layer 103 as an etch stop. The planarization
of the metal layer 319 for a contact plug and the barrier layer 207
may be performed using CMP. The barrier layer 207 remains along the
sidewalls and bottom of the first contact hole 105. A contact plug
319a is formed in the first contact hole 105 on the barrier layer
207. Thus, a barrier layer and a contact plug in one cell are
separated from a barrier layer and a contact plug in another
cell.
[0044] Referring now to FIG. 8C, a lower mold layer 111, a wet etch
stop layer 113, and an upper mold layer 115 are formed on the
contact plug 319a, the barrier layer 207, and the
interlevel-insulating layer 103. The lower mold layer 111, the wet
etch stop layer 113, and the upper mold layer 115 may comprise the
same materials and perform the same functions as described above
with reference to FIG. 6D.
[0045] Referring now to FIG. 8D, the upper mold layer 115, the wet
etch stop layer 113, and the lower mold layer 111 are patterned to
form a second contact hole 117 that exposes the upper surface of
the contact plug 319a and the barrier layer 207. Thus, an upper
mold layer pattern 115a, a wet etch stop pattern 113a, and a lower
mold layer pattern 111a are formed on the interlevel-insulating
layer 103.
[0046] Referring now to FIG. 8E, the second contact plug 117 is
filled with the same metal as the contact plug 319a to form a lower
electrode 319b of a stack type capacitor. The metal used to form
the lower electrode 319b may comprise a platinum group metal, such
as Pt, Ru, and/or Ir. As a result, the contact plug 319a and the
lower electrode 319b fill the first and second contact holes 105
and 117.
[0047] Referring now to FIG. 8F, the upper mold layer pattern 115a
is removed by wet etching using the wet etch stop pattern 113a as
an etch stop as shown in FIG. 6H. As shown in FIG. 4, a dielectric
layer 121 and an upper electrode 123 are formed on the
semiconductor substrate 101 on which the lower electrode 319b is
formed, thereby completing a semiconductor device having a MIM
capacitor.
[0048] FIGS. 9A through 9C are cross-sectional views that
illustrate operations in fabricating integrated circuit devices
having a MIM capacitor according to some embodiments of the present
invention described above with reference to FIG. 5. Methods of
fabricating an integrated circuit device according to embodiments
of the present invention illustrated in FIG. 5 are similar to
methods of fabricating an integrated circuit device according to
embodiments of the present invention illustrated in FIG. 4, with
the exception that a lower electrode 419a of the MIM capacitor is
cylindrical.
[0049] First, the operations described above with reference to
FIGS. 8A through 8D are performed. Referring now to FIG. 9A, a
metal layer 419 for a lower electrode is formed on the substrate
101 on which a second contact hole 117 is formed to expose upper
surfaces of a contact plug 319a and a barrier layer 207. The metal
layer 419 is formed along the sidewalls and bottom of the second
contact hole 117 and on an upper mold layer pattern 115a, but does
not fill the second contact hole 117. A sacrificial layer 421 is
formed on the surface of the substrate 101 to fill the second
contact hole 117. The sacrificial layer 421 may comprise a flowable
oxide.
[0050] Referring now to FIG. 9B, the sacrificial layer 421 is
planarized using the upper mold layer pattern 115a as an etch stop
so that the sacrificial layer 421 remains only in the second
contact hole 117. The metal layer 419 on the upper mold layer
pattern 115a is etched and the sacrificial layer 421 is planarized
using CMP. As a result, a lower electrode 419a is formed along the
sidewalls and bottom of the second contact hole 117.
[0051] Referring now to FIG. 9C, the sacrificial layer 421
remaining in the second contact hole 117 is removed. The upper mold
layer pattern 115a is removed using the wet etch stop pattern 113a
as an etch stop. Because the sacrificial layer 421 remaining in the
second contact hole 117 is flowable oxide, the upper mold layer
pattern 115a and the sacrificial layer 421 may be simultaneously
etched. As shown in FIG. 5, a dielectric layer 121 and an upper
electrode 123 are formed on the substrate 101 on which the lower
electrode 419a is formed, thereby completing a semiconductor device
having a MIM capacitor.
[0052] As described above, in integrated circuit devices according
to embodiments of the present invention, a contact plug filling a
contact hole may comprise a metal as a lower electrode instead of
TiN. As a result, cracks in an interlevel-insulating layer may be
reduced and a seam in the contact plug may be avoided. Moreover, a
barrier layer may be formed along the sidewalls and bottom of the
contact hole to increase adhesion between the barrier layer and the
contact plug and to reduce contact resistance.
[0053] In concluding the detailed description, it should be noted
that many variations and modifications can be made to the preferred
embodiments without substantially departing from the principles of
the present invention. All such variations and modifications are
intended to be included herein within the scope of the present
invention, as set forth in the following claims.
* * * * *