Patent Application
20240057320
This application claims priority under 35 USC § 119 to Korean Patent Application No. 10-2022-0100503, filed on Aug. 11, 2022, in the Korean Intellectual Property Office (KIPO), the contents of which are incorporated by reference herein in their entirety.
Various example embodiments relate to a semiconductor device. Particularly, various example embodiments relate to a DRAM (Dynamic random-access memory) device.
In a DRAM device, a landing pad structure electrically connected with a capacitor and an active pattern may be formed or arranged between bit line structures. As an aspect ratio of the landing pad structure increases, a structure of the landing pad structure becomes unstable. Thus, a defect in which an upper portion of the landing pad structure is broken may occur.
Various example embodiments provide a semiconductor device including a landing pad structure.
According to some example embodiments, there is provided a semiconductor device. The semiconductor device may include bit line structures on a substrate and extending in one direction, insulation structures between the bit line structures and spaced apart from each other, and a landing pad structure arranged in each of openings between the bit line structures and the insulation structures. The landing pad structure may include a first barrier metal pattern filling a portion of the opening, a second barrier metal pattern arranged along a surface profile of the opening on the first barrier metal pattern, and a first metal pattern on the second barrier metal pattern. The second barrier metal pattern may have end portions on the bit line structures adjacent the opening. The first metal pattern may have an upper surface higher than an upper surface of the bit line structure. An uppermost surface of the first barrier metal pattern may be lower than a lowermost surface of the first metal pattern.
According to some example embodiments, there is provided a semiconductor device. The semiconductor device may include a first gate structure below the upper surface of a substrate and extending in a first direction, bit line structures on the substrate and extending in a second direction perpendicular to the first direction, insulation structures between the bit line structures and spaced apart in the second direction, lower contact plug in a lower portion of each of contact holes between the bit line structures and the insulation structures, a landing pad structure on the lower contact plug, and a capacitor on the landing pad structure. The landing pad structure may include a first barrier metal pattern on the lower contact plug and filling a portion of the opening and upper portion of the first barrier metal pattern including a void, a second barrier metal pattern formed along a surface profile of the opening on the first barrier metal pattern and covering the void, and a first metal pattern on the second barrier metal pattern. The second barrier metal pattern may have end portions on the bit line structures adjacent the opening. The first metal pattern may have an upper surface higher than an upper surface of the bit line structure. An uppermost surface of the first barrier metal pattern may be lower than a lowermost surface of the first metal pattern.
According to some example embodiments, there is provided a semiconductor device. The semiconductor device may include a substrate including a cell region and a core/peripheral region, a first gate structure under an upper surface of the cell region of the substrate, bit line structures on the cell region of the substrate, a second gate structure on the core/peripheral region of the substrate, impurity regions at the substrate adjacent to both sides of the second gate structure, a landing pad structure between the bit line structures, a capacitor on the landing pad structure, a first wiring electrically connected to the first gate structure, a second wiring electrically connected to the bit line structure, and a third wiring electrically connected to the impurity regions and contacting the impurity regions. An upper surface of the landing pad structure may be higher than an upper surface of each of the bit line structures. Each of the landing pad structure, the first wiring, the second wiring, and the third wiring may include a first barrier metal pattern having a pillar shape, a second barrier metal pattern on the first barrier metal pattern, and a first metal pattern on the second barrier metal pattern. The first metal pattern may have an upper surface higher than an upper surface of the bit line structure. An uppermost surface of the first barrier metal pattern may be lower than a lowermost surface of the first metal pattern.
In various example embodiments, the landing pad structure included in the semiconductor device may include the first barrier metal pattern having a pillar shape, the second barrier metal pattern and the metal pattern disposed on the first barrier metal pattern. As the first barrier metal pattern is included in the landing pad structure, an aspect ratio of an opening for forming the metal pattern may decrease. Therefore, a void may not be included in the metal pattern or may be less likely to be included in the metal pattern. Alternatively or additionally, even if wet cleaning is performed after forming the landing pad structure, an upper portion of a void included in the landing pad structure may not be opened. Therefore, the landing pad structure may have a stable or more stable structure.
Various example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.
Hereinafter, various example embodiments will be described in detail with reference to the accompanying drawings.
Hereinafter, an extension direction of a first gate structure may be referred to as a first direction, and a direction intersecting or perpendicular to the first direction (e.g., an extension direction of a bit line) may be referred to as a second direction. In addition, a direction having an inclination with respect to the first direction may be referred to as a third direction.
Referring to
An upper portion of the substrate 100 may be etched to form a trench 102, and an isolation pattern 106 may be formed to fill the trench 102, e.g. with a process such as a shallow trench isolation (STI) process. A portion of the substrate between the isolation patterns 106 may be defined as an active pattern 104. The isolation pattern 106 may serve as a field region, and an upper surface of the active pattern 104 may serve as an active region. The active region may be disposed such that the third direction may be a longitudinal direction.
In some example embodiments, a width of the isolation pattern 106 in the core/peripheral region II may be greater than a width of the isolation pattern 106 in the cell region I.
After forming an impurity region (not shown) at an upper portion of the cell region I of the substrate 100 by, e.g., an ion implantation process such as a beamline ion implantation process, the active pattern 104 and the isolation pattern 106 may be partially etched to form a first recess extending in the first direction.
Thereafter, a first gate structure 116 may be formed in the first recess. The first gate structure 116 may include a first gate insulation layer 110, a first gate electrode 112 and a lower capping pattern 114.
The first gate structure 116 may extend in the first direction, and a plurality of first gate structures 116 may be spaced apart from each other in the second direction.
Referring to
A second gate insulation layer 121 may be formed on the active pattern 104 in, e.g. only in, the core/peripheral region II.
A first conductive layer 124 may be formed on the second buffer insulation layer 122 and the second gate insulation layer 121.
The first conductive layer 124, the second buffer insulation layer 122, the first buffer insulation layer 120 and upper portions of the active pattern 104 and the isolation pattern 106 in the cell region I may be etched to form a first opening 150 exposing the active pattern 104 on a bottom thereof. In some example embodiments, a middle portion in the longitudinal direction of each of the active patterns 104 in the cell region I may be exposed by the bottom of the first opening 150.
A second conductive layer 126 may be formed to fill the first opening 150. Upper surfaces of the first and second conductive layers 124 and 126 may be substantially coplanar with each other. The first and second conductive layers 124 and 126 may include polysilicon doped with impurities, and may be doped at the same, or different, concentrations of impurities. The first and second conductive layers 124 and 126 may be formed of the same material, so that the first and second conductive layers 124 and 126 may be merged into one lower conductive layer.
A barrier metal layer (not shown), a first metal layer 128 and a first capping layer 130 may be sequentially formed on an upper surface of the lower conductive layer. The first metal layer 128 may include, e.g., tungsten. The first capping layer may include, e.g., silicon nitride.
A first etching mask pattern (not shown) may be formed on the first capping layer 130 to cover the cell region I and expose a portion of the core/peripheral region II. The first capping layer 130, the first metal layer 128, the barrier metal layer and the first conductive layer 124 in the core/peripheral region II may be sequentially etched using the first etching mask pattern to form a second gate structure 142 and a preliminary bit line structure.
The second gate structure 142 may be formed in the core/peripheral region II. The second gate structure 142 may include the second gate insulation layer 121, a first conductive pattern 124a, a first metal pattern 128a and a first capping pattern 130a stacked. The preliminary bit line structure may be formed in the cell region I. The preliminary bit line structure may cover (e.g. partially or fully cover) the cell region I. The preliminary bit line structure may include the lower conductive layer, the first metal layer 128 and the first capping layer 130 stacked.
The preliminary bit line structure may extend to an edge of a core/peripheral region II adjacent to the cell region I. Thus, an end portion (e.g., a sidewall) of the preliminary bit line structure may be positioned in the core/peripheral region II.
A spacer 136 may be formed on a sidewall of the preliminary bit line structure and a sidewall of the second gate structure 142. In an etching process for forming the spacer 136, the first buffer insulation layer 120, the second buffer insulation layer 122, and the second gate insulation layer 121 between the spacers 136 may be removed, e.g. removed concurrently or together.
In some example embodiments, a nitride liner (not shown) may be further formed on an upper surface of the preliminary bit line structure, an upper surface of the second gate structure 142, surfaces of the spacer 136 and the substrate 100 therebetween. The nitride liner may include, e.g., silicon nitride.
An upper portion of the active pattern 104 adjacent to the second gate structures 142 may be doped with impurities to form an impurity region 144 serving as a source/drain. The second gate structure 142 and the impurity region 144 may serve as a transistor.
Referring to
A second capping layer may be formed on the preliminary bit line structure, the second gate structure 142 and the lower insulating interlayer 132. The second capping layer may include, e.g., silicon nitride. In some example embodiments, the first capping layer 130, the nitride liner, and the second capping layer may include the same material such as silicon nitride, and thus the first capping layer 130, the nitride liner, and the second capping layer may be merged into one nitride layer, e.g. one homogenous nitride layer.
The second capping layer and the first capping layer 130 in the cell region I may be patterned to form a second capping pattern 134a and a first capping pattern 130a in the cell region I and the core/peripheral region II. The first and second capping patterns 130a and 134a in the cell region I may have a line or linear shape extending in the second direction. The second capping pattern 134a may cover an entire upper portion of the core/peripheral region II.
The first metal layer 128, the barrier metal layer, the second conductive layer 126 and the first conductive layer 124 in the cell region I may be etched using the first and second capping patterns 130a and 134a as an etching mask. Accordingly, a first conductive pattern 124a, a barrier metal pattern (not shown), a first metal pattern 128a, and the first and second capping patterns 130a and 134a sequentially stacked may be formed on the active pattern 104 exposed by the first opening 150. In addition, the first conductive pattern 124a, the barrier metal pattern (not shown), the first metal pattern 128a, and the first and second capping patterns 130a and 134a sequentially stacked may be formed on the second buffer insulation layer 122 outside the first opening 150. As the first and second conductive layers 124 and 126 may be formed of the same material, and thus a conductive pattern formed by patterning the first and second conductive layers is referred to as the first conductive pattern 124a. In some example embodiments, a doping concentration of first conductive layer 124 may be the same as, or different than (e.g. greater than or less than), a doping concentration of the second conductive pattern 126; however, example embodiments are not limited thereto.
The first conductive pattern 124a, barrier metal pattern, first metal pattern 128a, first capping pattern 130a, and second capping pattern 134a sequentially stacked may serve as a bit line structure 140.
The bit line structure 140 may extend in the second direction, and a plurality of bit line structures 140 may be spaced apart from each other in the first direction. The bit line structure 140 may contact the active pattern 104 exposed by the first opening 150.
Referring to
As shown in
In some example embodiments, the spacer structure 152 may include a first spacer 152a covering a lower sidewall of the bit line structure 140 positioned in the first opening, a second spacer 152b on a top portion of the first spacer 152a to cover an upper sidewall of the bit line structure 140. In addition, third and fourth spacers (not shown) may be sequentially formed on a surface of the second spacer 152b.
However, a configuration of the spacer structure 152 may not be limited thereto, and the spacer structure 152 may include only a single spacer or two or more spacers.
A first insulating interlayer (not shown) may be formed to fill a gap between the spacer structures 152. After forming a second etching mask pattern (not shown) on the first insulating interlayer and the spacer structure 152, the first interlayer insulating layer may be etched using the second etching mask pattern to form a second opening (not shown).
In some example embodiments, the second etching mask pattern may extend in the first direction, and a plurality of the second etching mask pattern may be spaced apart from each other in the second direction. In this case, the second opening may be formed to overlap the first gate structure 116.
Thereafter, a fence insulation pattern 154 may be formed to fill the second opening. The fence insulation pattern 154 may be formed on the first gate structure 116. The fence insulation pattern 154 may include, e.g., a nitride such as silicon nitride.
The first insulating interlayer may be etched, and the second buffer insulation layer 122, the first buffer insulation layer 120, and a surface of the substrate 100 thereunder may be etched to form a third opening 156 exposing the surface of the substrate 100. The third opening 156 may be formed between the bit line structure 140 and the fence insulation pattern 154.
Referring to
In some example embodiments, a conductive layer may be formed to fill the third opening 156, and then an upper portion of the conductive layer may be removed to form the lower contact plug 158. The removing of the upper portion of the conductive layer may include an etch-back process. The conductive layer may include polysilicon doped with impurities. When the conductive layer is formed of the polysilicon, the conductive layer may easily fill the third opening 156 having a high aspect ratio.
In some example embodiments, a silicide pattern 159 may be formed on the lower contact plug 158. The silicide pattern 159 may include cobalt silicide; however, example embodiments are not limited thereto, and the silicide pattern 15 may include nickel silicide.
A third etching mask pattern (not shown) may be formed on structures in the cell region I and the core/peripheral region II. The third etch mask pattern may cover an entire upper portion of the cell region I. The third etching mask pattern may expose a region for forming contact holes in the core/peripheral region II.
Thereafter, layers exposed by the third etching mask pattern may be etched using the third etching mask pattern to form first to third contact holes 160, 162 and 164 in the core/peripheral region II.
For example, the first contact hole 160 exposing the first conductive pattern 124a of the bit line structure 140 may be formed in the core/peripheral region II adjacent to the cell region I. The second contact holes 162 exposing source/drain regions adjacent to both sides of the second gate structure 142 may be formed in the core/peripheral region II. In addition, the third contact hole 164 exposing the first gate electrode 112 of the first gate structure 116 may be formed in the core/peripheral region II adjacent to the cell region I.
The first to third contact holes 160, 162, and 164 may have different vertical depths to each other. The first to third contact holes 160, 162, and 164 may have bottom surfaces on different planes. In some example embodiments, the first to third contact holes 160, 162, and 164 may be formed by performing photo processes and etching processes of several times, e.g. performing a first photo/etch process to form the first contact holes 160, performing a second photo/etch process to form the second contact holes 162, and performing a third photo/etch process to form the third contact holes 164.
Through the above process, a space of the third opening 156 on the lower contact plug 158 may remain in the cell region (I), and the first to third contact holes 160, 162, and 164 may be formed in the core/peripheral region II.
Referring to
The first barrier metal layer 170 may completely fill the third opening 156. Accordingly, an upper surface of the first barrier metal layer 170 may be higher than an upper surface of the bit line structure 140.
The first barrier metal layer 170 may include, e.g., a metal such as titanium (Ti) and tantalum (Ta) and/or metal nitrides such as titanium nitride (TiN) and/or tantalum nitride (TaN).
In some example embodiments, when the third opening 156 has the high aspect ratio, a void or a seam may be included in the first barrier metal layer 170 filling the third opening 156. In some example embodiments, a void or a seam may also be included in the first barrier metal layer 170 filling at least one of the first to third contact holes 160, 162 and 164.
In some example embodiments, the void may not be included in the first barrier metal layer 170.
Referring to
During the etch-back process, the spacer structure 152 on an upper sidewall of the bit line structure 140 may be partially removed together. Accordingly, an inner width of the third opening 156 between the bit line structures 140 may be increased.
The upper surface of the first barrier metal pattern 170a in the third opening 156 may be lower than an uppermost portion of the third opening 156. An upper surface of the second barrier metal pattern 170b in the first contact hole 160 may be lower than an uppermost portion of the first contact hole 160. An upper surface of the third barrier metal pattern 170c in the second contact hole 162 may be lower than an uppermost part of the second contact hole 162. An upper surface of the fourth barrier metal pattern 170d in the third contact hole 164 may be lower than an uppermost portion of the third contact hole 164.
Each of or at least one of the first to fourth barrier metal patterns 170a, 170b, 170c, and 170d may have a pillar shape.
The upper surface of the first barrier metal pattern 170a in the cell region I may be lower than a lower surface of a second upper insulation pattern between landing pad structures subsequently formed (to be described below).
In some example embodiments, the seam or void v may be opened and included in the first barrier metal layer 170. In this case, the seam or void v or seam in the first barrier metal layer 170 may be opened by the etch-back process, so that an upper portion of the first barrier metal pattern 170a may have an opened void.
As the first barrier metal pattern 170a may be partially filled in the third opening 156 in the cell region I, a vertical height of a remaining space of the third opening 156 on the first barrier metal pattern 170a may be decreased. Alternatively or additional, the inner width of the third opening 156 may be expanded by partially removing the spacer structure 152. Accordingly, the aspect ratio of the remaining space of the third opening 156 may be decreased, and a manufacturing process may be improved.
As the second to fourth barrier metal patterns 170b, 170c, and 170d may be formed in the first to third contact holes 160, 162, and 164 in the core/peripheral region II, respectively, a vertical height of a remaining space of each of the first to third contact holes 160, 162 and 164 on the second to fourth barrier metal pattern 170b, 170c and 170d may be decreased. Accordingly, the aspect ratio of the remaining space of each of the first to third contact holes 160, 162 and 164 may be decreased, and a manufacturing process may be improved.
Referring to
The second barrier metal layer 174 may include, e.g., a metal such as titanium (Ti) and/or tantalum (Ta) and/or a metal nitride such as titanium nitride and/or tantalum nitride.
In the cell region I, when the upper portion of the first barrier metal pattern 170a has the opened void, the second barrier metal layer 174 may cover the void v. Therefore, an entrance of the void v may be closed by the second barrier metal layer 174.
A first metal layer 176 may be formed on the second barrier metal layer 174 to completely fill the third opening 156 and the first to third contact holes 160, 162 and 164. The first metal layer 176 may be formed as a landing pad structure 184 in the cell region I and an upper wiring in the core/peripheral region II, respectively, through subsequent processes. Therefore, the upper surface of the first metal layer 176 may be formed higher than at least the upper surfaces of the bit line structure 140 and the upper surfaces of the second capping pattern 134a.
The first to fourth barrier metal patterns 170a, 170b, 170c, and 170d may be already and partially filled in the third opening 156 and the first to third contact holes 160, 162, and 164, respectively. Therefore, spaces of the third opening 156 and the first to third contact holes 160, 162, and 164 for filling the first metal layer 176 may have a low aspect ratio. Thus, a void may not be formed, or may be less likely to be formed, in the first metal layer 176. Further, the third opening 156 may be sufficiently expanded in the etch-back process of the first barrier layer, so that the third opening 156 may have a wide inner width. Therefore, the void may not be formed, or may be less likely to be formed, in the first metal layer 176 in the third opening 156.
The first metal layer 176 may include, e.g., tungsten.
Referring to
The fourth etch mask pattern may serve as a mask for forming wiring patterns in the core/peripheral region II. The fourth etching mask pattern may cover entire of the first metal layer 176 in the cell region I. In addition, the fourth etching mask pattern may at least cover or partially cover upper portions of first to third contact holes 160, 162, and 164 in the core/peripheral region II.
The first metal layer 176 and the second barrier metal layer 174 may be etched, e.g. may be anisotropically etched using the fourth etching mask pattern, and then an upper portion of the second capping pattern 134a in the core/peripheral region II may be partially etched to form barrier metal patterns and metal patterns. The barrier metal patterns and metal patterns may be formed on the second capping pattern 134a to fill the first to third contact holes 160, 162, and 164 in the core/peripheral region II. In some example embodiments, the metal patterns formed on the second capping pattern 134a may have a line shape.
Through the above process, a first wiring 180a including the second barrier metal pattern 170b, the fifth barrier metal pattern 174b and the third metal pattern 176b stacked may be formed in the first contact hole and on the second capping pattern 134a. The second barrier metal pattern 170b may fill a lower portion of the first contact hole 160. The fifth barrier metal pattern 174b may cover an upper surface of the second barrier metal pattern 170b, and may be formed along a sidewall of the first contact hole 160 and an upper surface of the second capping pattern 134a.
A second wiring 180b including a third barrier metal pattern 170c, a sixth barrier metal pattern 174c, and a fourth metal pattern 176c stacked may be formed in the second contact hole 162 and on the second capping pattern 134a. The third barrier metal pattern 170c may fill a lower portion of the second contact hole 162. The sixth barrier metal pattern 174c may cover an upper surface of the third barrier metal pattern 170c, and may be formed along a sidewall of the second contact hole 162 and the upper surface of the second capping pattern 134a.
A third wiring 180c including a fourth barrier metal pattern 170d, a seventh barrier metal pattern 174d and a fifth metal pattern 176d stacked may be formed in the third contact hole 164 and on the second capping pattern 134a. The fourth barrier metal pattern 170d may fill a lower portion of the third contact hole 160. The seventh barrier metal pattern 174d may cover an upper surface of the fourth barrier metal pattern 170d, and may be formed along a sidewall of the third contact hole 164 and the upper surface of the second capping pattern 134a.
When the etching process is performed, a fourth opening 182 may be formed between the wirings.
Thereafter, a first upper insulation pattern 183 may be formed to fill the fourth opening 182 between the wirings. The first upper insulation pattern 183 may include, e.g., silicon oxide.
Referring to
The fifth etch mask pattern may serve as a mask for forming the landing pad structure 184 in the cell region I. The fifth etch mask pattern may cover entire of the third to fifth metal patterns 176b, 176c and 176d and the first upper insulation pattern 183 in the core/peripheral region II. In addition, the fifth etch mask pattern may selectively cover or at least partially cover a portion for forming the landing pad structure 184 in the cell region I.
The first metal layer 176 and the second barrier metal layer 174 in the cell region I may be anisotropically etched using the fifth etch mask pattern, and then upper portions of the second capping pattern 134a and the spacer structure 152 in the cell region I may be partially etched to form an eighth barrier metal pattern 174a and a second metal pattern 176a on the first barrier metal pattern 170a.
Accordingly, the landing pad structure 184 including the first barrier metal pattern 170a, the eighth barrier metal pattern 174a, and the second metal pattern 176a may be formed on the silicide pattern 159 in the cell region I. In addition, a fifth opening 186 may be formed between upper portions of the landing pad structures 184.
Upper portions of the second capping pattern 134a of the bit line structure 140 and the spacer structure 152 may include a recess formed by the fifth opening 186. An upper surface of the first barrier metal pattern 170a may be lower than a lower surface of the recess.
In the landing pad structure 184, the first barrier metal pattern 170a may be formed on silicide pattern 159 to partially fill the third opening 156. The eighth barrier metal pattern 174a may be conformally formed on upper surfaces of the first barrier metal pattern 170a, the spacer structure 152, and the bit line structure 140. The second metal pattern 176a may be formed on the eighth barrier metal pattern 174a. For example, the eighth barrier metal pattern 174a may be formed to cover the upper surface of the first barrier metal pattern 170a of the landing pad structure 184.
An uppermost surface of the eighth barrier metal pattern 174a may be higher than a lowermost surface of the second metal pattern 176a. An uppermost surface of the first barrier metal pattern 170a may be lower than the lowermost surface of the second metal pattern 176a. A void may not be included, or may less likely be included, in the second metal pattern 176a.
In the landing pad structure 184, a lower width of a structure in which the eighth barrier metal pattern 174a and the second metal pattern 176a are stacked may be greater than an upper width of the first barrier metal pattern 170a.
Referring to
In some example embodiments, the wet cleaning process may be performed using a chemical containing hydrogen fluoride (HF) such as a buffered HF mixture. As the metal residue between the second metal patterns 176a may be removed by the wet cleaning process, defects in which adjacent second metal patterns 176a are electrically connected to each other due to the metal residue may be decreased.
An edge portion of the eighth barrier metal pattern 174a may be exposed by the fifth opening 186. For example, an end portion of the eighth barrier metal pattern 174a contacting an uppermost portion of the bit line structure 140 and an end portion of the eighth barrier metal pattern 174a contacting one upper wall of the spacer structure 152 may be exposed by the fifth opening 186. In the wet cleaning process, the exposed end portions of the eighth barrier metal pattern 174a may be partially etched. Accordingly, the eighth barrier metal pattern 174a may have recessed portions from the second metal pattern 176a thereon. For example, the end portion of the eighth barrier metal pattern 174a contacting the uppermost portion of the bit line structure 140 may have an undercut shape from a sidewall of the upper second metal pattern 176a. The end portion of the eighth barrier metal pattern 174a contacting the one upper wall of the spacer structure 152 may have the recessed portion in a direction toward the substrate 100.
A distance between the end portion of the eighth barrier metal pattern 174a contacting the one upper wall of the spacer structure 152 and the void v included in the first barrier metal pattern 170a may be sufficiently long. Thus, in the wet cleaning process, the first barrier metal pattern 170a covered by the eighth barrier metal pattern 174a may not be etched. Even if the end portion of the eighth barrier metal pattern 174a is partially removed by the wet cleaning process, the void v included in the first barrier metal pattern 170a may not be exposed. Accordingly, the landing pad structure 184 may have a stable or more stable structure. In addition, defects in which an upper portion of the landing pad structure 184 are broken due to structural instability of the landing pad structure 184 may be decreased.
Referring to
An etch stop layer 190 may be formed on the second upper insulation pattern 188 and the landing pad structure 184. A memristor and/or a capacitor 192 may be formed on the landing pad structure 184 passing through the etch stop layer 190. The capacitor 192 may contact the landing pad structure 184. The capacitor 192 may include a lower electrode 192a, a dielectric layer 192b and an upper electrode 192c.
As described above, a memory device such as a DRAM device may be manufactured.
The semiconductor device may include the following structural features.
The structural features of the semiconductor device are described with reference to
Referring to
The substrate 100 may include one or more of silicon, germanium, silicon-germanium, or a group III-V compound such as GaP, GaAs, or GaSb. In some example embodiments, the substrate 100 may include a Silicon On Insulator (SOI) substrate or a Germanium On Insulator (GOI) substrate. The substrate 100 may be doped or undoped.
The substrate 100 may include a trench for isolation, and an isolation pattern 106 may be formed in the trench.
The first gate structure 116 may be disposed inside the substrate 100 in the cell region I. For example, the first gate structure 116 may pass through upper portions of an active pattern 104 and the isolation pattern 106, and may extend in the first direction. A plurality of first gate structures 116 may be spaced apart from each other in the second direction. The first gate structure 116 may extend to an edge of a core/peripheral region II adjacent to the cell region I.
The first gate structure 116 may include a first gate insulation layer 110, a first gate electrode 112 and a lower capping pattern 114.
The first gate insulation layer 110 may include, e.g., an oxide such as silicon oxide. The first gate electrode 112 may include, e.g., one or more of tungsten (W), titanium (Ti), and/or tantalum (Ta), and/or a metal nitride such as tungsten nitride, titanium nitride, or tantalum nitride. The lower capping pattern 114 may include, e.g., a nitride such as silicon nitride.
A first buffer insulation layer 120 and a second buffer insulation layer 122 sequentially stacked on the active pattern 104, the isolation pattern 106 and the lower capping pattern 114 of the cell region I. A second gate insulation layer 121 may be formed on the active pattern 104 of the core/peripheral region II.
The bit line structure 140 in the cell region I may include a first conductive pattern 124a, a barrier metal pattern (not shown), a first metal pattern 128a, a first capping pattern 130a, and a second capping pattern 134a sequentially stacked. In some example embodiments, the bit line structure 140 may be formed on the active pattern 104 and the second buffer insulation layer 122, and may extend in the second direction.
A portion of the first conductive pattern 124a in the bit line structure 140 may be formed in the first opening 150 exposing an upper surface of the active pattern 104 and upper surfaces of the isolation pattern 106 and the lower capping pattern 114 adjacent the active pattern 104. Accordingly, the portion of the first conductive pattern 124a may contact the upper surface of the active pattern 104 exposed by the first opening 150. The first conductive pattern 124a may include, e.g., polysilicon doped with impurities.
The barrier metal pattern may include, e.g., a metal such as titanium (Ti) and/or tantalum (Ta) and/or a metal nitride such as titanium nitride and/or tantalum nitride. The first metal pattern 128a may include, e.g., a metal such as tungsten W. The first and second capping patterns 130a and 134a may include, e.g., a nitride such as silicon nitride.
The second gate structure 142 in the core/peripheral region II may include a second gate insulation layer 121, a first conductive pattern 124a, a first metal pattern 128a, and a first capping pattern 130a sequentially stacked.
As such, the second gate structure 142 in the core/peripheral region II and the bit line structure 140 in the cell region I may include the first conductive pattern 124a, the first metal pattern 128a and the first capping pattern 130a sequentially stacked. For example, the second gate structure 142 and the bit line structure 140 may have the same stacked structure.
A spacer 136 may be formed on a sidewall of the second gate structure 142. An end portion in the second direction of the bit line structure 140 may extend to an edge of the core/peripheral area II adjacent to the cell region I. The spacers 136 may be formed on a sidewall in the second direction of the bit line structure 140.
A lower insulating interlayer 132 may be formed on the substrate 100 between the second gate structures 142. The second capping pattern 134a may be formed on the second gate structure 142 and the lower insulating interlayer 132 in the core/peripheral region II.
The spacer structure 152 may be formed on sidewalls of the bit line structure 140. The spacer structure 152 may extend in the second direction. In example embodiments, the spacer structure 152 may include a plurality of spacers stacked from the sidewalls of the bit line structure 140. For example, the spacer structure 152 may include a first spacer 152a covering a lower sidewall of the bit line structure 140 positioned in the first opening and a second spacer 152b on a top portion of the first spacer to cover an upper sidewall of the bit line structure 140. In addition, third and fourth spacers (not shown) may be sequentially formed on the surface of the second spacer 152b.
In some example embodiments, the spacer structure 152 may include an air spacer serving as empty space. The fence insulation pattern 154 may be formed on the second buffer insulation layer 122. The fence insulation pattern 154 may be formed on the first gate structure 116 positioned between the bit line structures 140. The fence insulation pattern 154 may include, e.g., a nitride such as silicon nitride.
A third opening 156 exposing the active pattern 104 may be formed between the bit line structures 140 and between the fence insulation patterns 154. The lower contact plug 158 and the landing pad structure 184 may be formed in the third opening 156.
The lower contact plug 158 may contact the substrate 100 to fill a lower portion of the third opening 156. The lower contact plug 158 may include, e.g., polysilicon doped with impurities. A silicide pattern 159 may be further formed on the lower contact plug 158. Since the lower contact plug 158 including the polysilicon is formed, a parasitic capacitance between the lower contact plug 158 and the bit line structure 140 may be decreased.
The landing pad structure 184 may be formed on the lower contact plug 158. The landing pad structure 184 may include a first barrier metal pattern 170a, an eighth barrier metal pattern 174a, and a second metal pattern 176a.
The first barrier metal pattern 170a may be formed on the lower contact plug 158, and partially fill a remaining space of the third opening 156 on the lower contact plug 158. The first barrier metal pattern 170a may have a pillar shape. In some example embodiments, a void v may be included in an upper portion of the first barrier metal pattern 170a.
The eighth barrier metal pattern 174a may be formed along a surface profile of the third opening 156 on the first barrier metal pattern 170a. The eighth barrier metal pattern 174a may have end portions on the bit line structures adjacent the third opening 156. The eighth barrier metal pattern 174a may cover an entrance of the void (v). As the eighth barrier metal pattern 174a may be formed, a distance from the void v to an end portion (e.g., an uppermost portion) of the eighth barrier metal pattern 174a may be increased.
In a cross-sectional view, the eighth barrier metal pattern 174a may have a first portion contacting an upper surface of the first barrier metal pattern 170a, a second portion contacting one sidewall of the bit line structure 140 and a third portion contacting the upper surface and one sidewall of the bit line structure 140 facing the second portion.
The second metal pattern 176a may be formed on the eighth barrier metal pattern 174a. A void may not be included, or may be less likely to be included, in the second metal pattern 176a.
An edge portion of the eighth barrier metal pattern 174a may include a recessed portion that may be recessed from the second metal pattern 176a disposed thereon. Particularly, an end portion of the eighth barrier metal pattern 174a contacting an uppermost portion of the bit line structure 140 may be recessed from a lower sidewall of the upper second metal pattern 176a. An end portion of the eighth barrier metal pattern 174a contacting the one upper wall of the spacer structure 152 may include the recessed portion in a direction toward the substrate 100.
A stacked structure of the eighth barrier metal pattern 174a and the second metal pattern 176a may be separated on the bit line structure 140.
An uppermost surface of the first barrier metal pattern 170a may be lower than a lowermost surface of the second metal pattern 176a.
In example embodiments, each of the first barrier metal pattern 170a and the eighth barrier metal pattern 174a may include, e.g., titanium (Ti), tantalum (Ta), titanium nitride (TiN), or tantalum nitride (TaN). In example embodiments, the second metal pattern 176a may include, e.g., tungsten.
A fifth opening 186 may be formed between stacked structures of the eighth barrier metal pattern 174a and the second metal pattern 176a. A second upper insulation pattern 188 may be formed in the fifth opening 186. The second upper insulation pattern 188 may contact the eighth barrier metal pattern 174a and the second metal pattern 176a. The second upper insulation pattern 188 may include, e.g., silicon oxide.
An upper portion of the bit line structure 140 positioned on a lower surface of the fifth opening 186 may have a recessed shape. That is, the upper portion of the bit line structure 140 disposed between adjacent second metal patterns 176a may include a recessed portion.
In various example embodiments, upper surfaces of the landing pad structure 184 and the second upper insulation pattern 188 may be coplanar with each other. In the cell region I, an upper surface of the first barrier metal pattern 170a may be lower than a lower surface of the second upper insulation pattern 188. An upper surface of the first barrier metal pattern 170a may be lower than a lower surface of the recessed portion of the bit line structure 140.
In the landing pad structure 184, a lower width of a structure in which the eighth barrier metal pattern 174a and the second metal pattern 176a are stacked may be greater than an upper width of the first barrier metal pattern 170a.
An etch stop layer 190 may cover the landing pad structure 184 and the second upper insulation pattern 188b.
A capacitor 192 may contact an upper surface of the landing pad structure 184 passing through the etch stop layer 190.
A first contact hole 160 may expose the first conductive pattern 124a of an edge of the bit line structure 140 in the core/peripheral region II adjacent to the cell region I. A first wiring including a second barrier metal pattern 170b, a fifth barrier metal pattern 174b and a third metal pattern 176b may be formed in the first contact hole 160 and on the second capping pattern 134a. The second barrier metal pattern 170b may fill a lower portion of the first contact hole 160. The fifth barrier metal pattern 174b may cover an upper surface of the second barrier metal pattern 170b, and may be conformally formed on a sidewall of the first contact hole 160 and an upper surface of the second capping pattern 134a.
A second contact hole 162 may expose impurity regions 144 adjacent to both sides of the second gate structure 142 in the core/peripheral region II. A second wiring including a third barrier metal pattern 170c, a sixth barrier metal pattern 174c and a fourth metal pattern 176c may be formed in the second contact hole 162 and on the second capping pattern 134a. The third barrier metal pattern 170c may fill a lower portion of the second contact hole 162. The sixth barrier metal pattern 174c may cover an upper surface of the third barrier metal pattern 170c, and may be formed, e.g., conformally formed on a sidewall of the second contact hole 162 and the upper surface of the second capping pattern 134a.
A third contact hole 164 may expose the first gate electrode 112 at an edge of the first gate structure 116 in the core/peripheral region II adjacent to the cell region I. A third wiring 180c including a seventh barrier metal pattern 174d, a seventh barrier metal pattern 174d, and a fifth metal pattern 176d may be formed in the third contact hole 164 and on the second capping pattern 134a. The seventh barrier metal pattern 174d may fill a lower portion of the third contact hole 160. The seventh barrier metal pattern 174d may cover an upper surface of the fourth barrier metal pattern 170d, and may be formed, e.g., conformally formed on a sidewall of the third contact hole 164 and the upper surface of the second capping pattern 134a.
The second to fourth barrier metal patterns 170b, 170c, and 170d may include at least one material that is the same as at least one material of the first barrier metal pattern 170a. Each of the second to fourth barrier metal patterns 170b, 170c, and 170d may have a pillar shape. The fifth to seventh barrier metal patterns 174b, 174c, and 174d may include a material as a material of the eighth barrier metal pattern 174a. The second to fifth metal patterns 176a, 176b, 176c, and 176d may include the same material to each other.
As such, each of the first to third wirings 180a, 180b, and 180c may have a stacked structure the same as a stacked structure of the landing pad structure 184.
In some example embodiments, at least one of the first to third wirings 180a, 180b, and 180c may have a stacked structure different from that of the landing pad structure 184. In this case, the wiring having a stacked structure different from that of the pad pattern structure 184 may be formed by performing etching, deposition, and patterning processes different from the processes of forming the pad pattern structure 184.
The semiconductor device shown in
Referring to
The pad pattern structure 184a may include a first barrier metal pattern 170a, an eighth barrier metal pattern 174a, and a second metal pattern 176a.
The first barrier metal pattern 170a may fill the lower portion of the third opening 156. The first barrier metal pattern 170a may contact the substrate 100 exposed by the third opening 156. The first barrier metal pattern 170a may have a pillar shape. In example embodiments, a void may be included in the first barrier metal pattern 170a.
The eighth barrier metal pattern 174a may be formed along a surface profile of the third opening 156 on the first barrier metal pattern 170a. The eighth barrier metal pattern 174a may cover an entrance of the void.
A spacer structure on an upper sidewall of the third opening 156 over the first barrier metal pattern 170a may be partially etched. Accordingly, a width of the third opening 156 over the first barrier metal pattern 170a may be greater than that of the third opening 156 thereunder.
The second metal pattern 176a may be formed on the eighth barrier metal pattern 174a. A void may not be included, or may be less likely to be included in the second metal pattern 176a. An edge portion of the eighth barrier metal pattern 174a may include a recessed portion that may be recessed from the second metal pattern 176a disposed thereon.
The semiconductor device may be manufactured by processes substantially the same as processes as that described with reference to
As described above, the semiconductor device may include a structurally stable landing pad structure. Accordingly, the semiconductor device may have desired or improved electrical characteristics.
The foregoing is illustrative of various example embodiments and is not to be construed as limiting thereof. Although a few example embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the novel teachings and advantages of the present inventive concept. Accordingly, all such modifications are intended to be included within the scope as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of various example embodiments and is not to be construed as limited to the specific example embodiments disclosed, and that modifications to the disclosed example embodiments, as well as other example embodiments, are intended to be included within the scope of the appended claims. Furthermore example embodiments are not necessarily mutually exclusive with one another. For example, some example embodiments may include one or more features described with reference to one or more figures, and may also include one or more other features described with reference to one or more other figures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0100503 | Aug 2022 | KR | national |
