US20200335510A1 - Semiconductor structure and manufacturing method thereof - Google Patents
Semiconductor structure and manufacturing method thereof Download PDFInfo
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- US20200335510A1 US20200335510A1 US16/387,650 US201916387650A US2020335510A1 US 20200335510 A1 US20200335510 A1 US 20200335510A1 US 201916387650 A US201916387650 A US 201916387650A US 2020335510 A1 US2020335510 A1 US 2020335510A1
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 82
- 238000004519 manufacturing process Methods 0.000 title claims description 33
- 230000005055 memory storage Effects 0.000 claims abstract description 41
- 238000002955 isolation Methods 0.000 claims abstract description 40
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 230000005641 tunneling Effects 0.000 claims description 20
- 238000005530 etching Methods 0.000 abstract description 37
- 239000010410 layer Substances 0.000 description 377
- 238000000034 method Methods 0.000 description 42
- 230000008569 process Effects 0.000 description 40
- 239000000463 material Substances 0.000 description 24
- 230000000903 blocking effect Effects 0.000 description 21
- 230000004888 barrier function Effects 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 229910052814 silicon oxide Inorganic materials 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 4
- 229920005591 polysilicon Polymers 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000008186 active pharmaceutical agent Substances 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B43/00—EEPROM devices comprising charge-trapping gate insulators
- H10B43/20—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels
- H10B43/23—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels with source and drain on different levels, e.g. with sloping channels
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B41/00—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates
- H10B41/10—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by the top-view layout
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B43/00—EEPROM devices comprising charge-trapping gate insulators
- H10B43/30—EEPROM devices comprising charge-trapping gate insulators characterised by the memory core region
-
- H01L27/1158—
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/76—Making of isolation regions between components
- H01L21/762—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers
- H01L21/76224—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using trench refilling with dielectric materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
- H01L29/417—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions carrying the current to be rectified, amplified or switched
- H01L29/41725—Source or drain electrodes for field effect devices
- H01L29/41741—Source or drain electrodes for field effect devices for vertical or pseudo-vertical devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B41/00—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates
- H10B41/20—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by three-dimensional arrangements, e.g. with cells on different height levels
- H10B41/23—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by three-dimensional arrangements, e.g. with cells on different height levels with source and drain on different levels, e.g. with sloping channels
- H10B41/27—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by three-dimensional arrangements, e.g. with cells on different height levels with source and drain on different levels, e.g. with sloping channels the channels comprising vertical portions, e.g. U-shaped channels
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B43/00—EEPROM devices comprising charge-trapping gate insulators
- H10B43/10—EEPROM devices comprising charge-trapping gate insulators characterised by the top-view layout
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B43/00—EEPROM devices comprising charge-trapping gate insulators
- H10B43/20—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B43/00—EEPROM devices comprising charge-trapping gate insulators
- H10B43/20—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels
- H10B43/23—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels with source and drain on different levels, e.g. with sloping channels
- H10B43/27—EEPROM devices comprising charge-trapping gate insulators characterised by three-dimensional arrangements, e.g. with cells on different height levels with source and drain on different levels, e.g. with sloping channels the channels comprising vertical portions, e.g. U-shaped channels
Definitions
- the present disclosure relates to a semiconductor structure and a manufacturing method of the semiconductor structure.
- the disclosure relates in general to a semiconductor structure and a manufacturing method thereof.
- a pair of vertical memory structures both have horizontal C-shaped cross sections and are separated from each other by an isolation trench; accordingly, the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved.
- the semiconductor structure includes a substrate, a plurality of conductive layers, a plurality of dielectric layers, an isolation structure, a first memory structure, and a second memory structure.
- the conductive layers and the dielectric layers are interlaced and stacked on the substrate.
- the isolation structure is disposed on the substrate and through the conductive layers and the dielectric layers.
- Each of the first memory structure and the second memory structure has a radius of curvature.
- the first memory structure and the second memory structure penetrate through the conductive layers and the dielectric layers are disposed on opposite sidewalls of the isolation structure.
- Each of the first memory structure and the second memory structure includes a memory structure layer, a channel layer, and at least two protecting structures.
- the memory structure layer includes a memory storage layer.
- the channel layer is disposed between the memory structure layer and the isolation structure.
- the protecting structures are disposed at two ends of the memory storage layer, in which an etching selectivity to the protecting structures is different from an etching selectivity to the memory storage layer.
- the memory structure layer further includes a blocking layer and a tunneling layer.
- the blocking layer is disposed on sidewalls of the conductive layers and the dielectric layers.
- the memory storage layer is disposed between the blocking layer and the tunneling layer.
- the protecting structures are disposed between the blocking layer and the tunneling layer and adjoin the memory storage layer.
- each of the first memory structure and the second memory structure further includes a dielectric structure and a conductive plug layer, the dielectric structure is disposed between the channel layer and the isolation structure, and the conductive plug layer is disposed on the dielectric structure.
- each of the conductive layers further includes a barrier layer and a metal layer disposed on the barrier layer.
- the semiconductor structure further includes a plurality of high-k dielectric layers disposed between the dielectric layers and the barrier layers, respectively.
- the memory structure layer and the channel layer corresponding to the first memory structure are respectively interconnected with the memory structure layer and the channel layer corresponding to the second memory structure at a bottom surface of the isolation structure.
- the memory structure layer and the channel layer corresponding to the first memory structure are respectively separated from the memory structure layer and the channel layer corresponding to the second memory structure by the isolation structure.
- each of the channel layers is in contact with the substrate.
- the semiconductor structure further includes two contact structures, each electrically connected to the first memory structure and the second memory structure.
- the semiconductor structure further includes at least a signal line interconnecting the corresponding one of the conductive structures.
- the semiconductor structure further includes two signal lines connecting to the conductive structures, respectively.
- the manufacturing method of the semiconductor structure includes the following steps of: forming a plurality of insulating layers and a plurality of dielectric layers on a substrate, in which the insulating layers and the dielectric layers are interlaced and stacked on the substrate; forming a memory structure cluster on the substrate and through the insulating layers and the dielectric layers, in which the memory structure cluster includes a channel layer, a conductive plug layer, and a memory structure layer including a memory storage layer; forming a trench through the insulating layers, the dielectric layers, and the memory structure cluster, such that the memory structure cluster is separated into a first memory structure and a second memory structure, and portions of the insulating layers and portions of the memory storage layer are exposed from the trench; removing the exposed portions of the insulating layers and the exposed portions of the memory storage layer to respectively form a first group of spaces and a second group of spaces; filling a plurality of protecting structures in the first group of spaces and the second group of spaces; removing portions of the protecting
- replacing the insulating layers with the conductive layers includes: removing the insulating layers, after the insulating layers are exposed, to form a third group of spaces between the dielectric layers; filling a plurality of conductive layers in the first group of spaces and the third group of spaces.
- the manufacturing method of the semiconductor structure further includes: forming an isolation structure in the trench and on the memory structure cluster and a topmost layer of the dielectric layers after filling the conductive layers in the first group of spaces and the third group of spaces.
- the memory structure cluster further includes a dielectric structure
- the tunneling layer is disposed between the dielectric structure and the memory structure layer
- forming the memory structure cluster on the substrate and through the insulating layers and the dielectric layers includes: forming a recess with an elliptical profile, in which the recess penetrates the insulating layers and the dielectric layers; forming the memory structure layer in the recess and on the topmost layer of the dielectric layers; forming the channel layer on the memory structure layer; forming the dielectric structure on the channel layer to fill the recess; replacing a top portion of the dielectric structure with the conductive plug layer; removing a portion of the memory structure layer, a portion of the conductive plug layer, and a portion of the channel layer which are exceeded outside the recess.
- forming the trench through the insulating layers, the dielectric layers, and the memory structure cluster includes: removing portions of the insulating layers, portions of the dielectric layers, a portion of the channel layer, and a portion of the conductive plug layer, such that the memory structure layer and the channel layer corresponding to the first memory structure are respectively interconnected with the memory structure layer, the channel layer, and the dielectric structure corresponding to the second memory structure at a bottom of the trench.
- forming the trench through the insulating layers, the dielectric layers, and the memory structure cluster includes: removing portions of the insulating layers, portions of the dielectric layers, a portion of the channel layer, and a portion of the conductive plug layer, such that the memory structure layer and the channel layer corresponding to the first memory structure are respectively separated from the memory structure layer and the channel layer corresponding to the second memory structure by the trench.
- the manufacturing method of the semiconductor structure further includes: forming an isolation layer on the memory structure cluster and the topmost layer of the dielectric layers; forming two contact structures, each electrically connected to the first memory structure and the second memory structure.
- the first memory structure and the second memory structure are separated from each other by the isolation structure, such that the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved.
- the conductive layers stacked between the dielectric layers can help improve the program speed as well as the erase speed of the semiconductor structure due to the lower resistance.
- the aforementioned embodiments of the present disclosure also provide a method of replacing the insulating layers with the conductive layers while preserving the memory storage layer which is made of the same material as the insulating layers, thereby simplifying the process of manufacturing the semiconductor structure.
- FIGS. 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A, 13A, and 14A are top views of a process at various stages of a manufacturing method of a semiconductor structure according to an embodiment of the present disclosure
- FIGS. 1B, 2B, 3B-3C, 4B-4C, 5B-5C, 6B-6C, 7B-7D, 8B-8F, 9B-9F, 10B-10F, 11B-11F, 12B , 12 D- 12 F, 13 B- 13 E, and 14 B- 14 E are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor structure according to an embodiment of the present disclosure;
- FIG. 12C is a partial enlargement diagram of FIG. 12B ;
- FIGS. 15A, 16A, 17A, 18A and 19A are top views of a process at various stages of a manufacturing method of a semiconductor device according to an embodiment of the present disclosure
- FIGS. 15B-15D, 16B-16D, 17B, 18B, 19B-19D are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor device according to an embodiment of the present disclosure
- FIG. 20A is a top view of a process at various stages of a manufacturing method of a semiconductor structure according to another embodiment of the present disclosure
- FIG. 20B is a cross-sectional view of a process at various stages of a manufacturing method of a semiconductor structure according to another embodiment of the present disclosure.
- FIG. 21A is a top view of a process at various stages of a manufacturing method of a semiconductor device according to another embodiment of the present disclosure.
- FIGS. 21B-21C are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor device according to another embodiment of the present disclosure.
- a semiconductor structure and a method of manufacturing the same are provided.
- the method of manufacturing the semiconductor structure will be discussed first in the article.
- the term “top view” may be used herein for ease of description to refer to as a cross-sectional view of a topmost layer of the semiconductor structure in order to highlight the technical features of the inventive concept.
- some of the secondary elements may be omitted in the drawings accompanying the following embodiments.
- FIGS. 1A-1B, 2A-2B, 3A-3C, 4A-4C, 5A-5C, 6A-6C, 7A-7D, 8A-8F, 9A-9F, 10A-10F, 11A - 11 F, 12 A- 12 F, 13 A- 13 E, and 14 A- 14 E are views of a process at various stages of a manufacturing method of a semiconductor structure 100 according to an embodiment of the present disclosure.
- the elements covered beneath in the semiconductor structure 100 are illustrated in solid lines in the drawings.
- FIGS. 1A and 1B in which FIG. 1A is a top view of step S 10 of forming the semiconductor structure 100 , and FIG. 1B is a cross-sectional view taken along line 1 B- 1 B in FIG. 1A .
- step S 10 a substrate 110 is provided, and a plurality of insulating layers 120 and a plurality of dielectric layers 130 are interlaced and stacked on the substrate 110 .
- a recess 400 is then formed. The recess 400 penetrates through the insulating layers 120 and the dielectric layers 130 and stops below a bottommost layer of the insulating layers 120 . As shown in FIG.
- the recess 400 has an elliptical profile, in a top view, and the long axis (the longer diameter) of the elliptical cross section may be as long as about 150 nm.
- a thickness T of the bottommost layer of the insulating layers 120 may be larger than a thickness of other layers of the insulating layers 120 .
- FIGS. 2A and 2B in which FIG. 2A is a top view of step S 20 of forming the semiconductor structure 100 , and FIG. 2B is a cross-sectional view taken along line 2 B- 2 B in FIG. 2A .
- a memory structure layer 140 is conformally formed in the recess 400 and on a topmost layer of the dielectric layers 130 , and a channel layer 150 is then conformally formed on the memory structure layer 140 .
- the memory structure layer 140 includes a blocking layer 142 , a memory storage layer 144 , and a tunneling layer 146 .
- the blocking layer 142 is disposed on sidewalls of the insulating layers 120 and the dielectric layers 130 and the topmost layer of the dielectric layers 130 , the memory storage layer 144 is disposed on the blocking layer 142 , and the tunneling layer 146 is disposed on the memory storage layer 144 .
- the blocking layer 142 and the tunneling layer 146 may be made of a material including silicon oxide or other dielectric
- the memory storage layer 144 may be made of a material including silicon nitride or other material that is able to trap electrons
- the channel layer 150 may be made of a material including undoped polysilicon, but the present disclosure is not limited in this regard.
- FIGS. 3A-3C in which FIG. 3A is a top view of step S 30 of forming the semiconductor structure 100 , FIG. 3B is a cross-sectional view taken along line 3 B- 3 B in FIG. 3A , and FIG. 3C is a cross-sectional view taken along line 3 C- 3 C in FIG. 3A .
- a dielectric structure 160 is disposed on the channel layer 150 to fill the recess 400 and formed over the topmost layer of the dielectric layers 130 .
- a portion of the dielectric structure 160 which is formed over the topmost layer of the dielectric layers 130 is higher than a top surface of the channel layer 150 by a height HD.
- the dielectric structure 160 may be made of a material including silicon oxide or other dielectric.
- FIGS. 4A-4C in which FIG. 4A is a top view of step S 40 of forming the semiconductor structure 100 , FIG. 4B is a cross-sectional view taken along line 4 B- 4 B in FIG. 4A , and FIG. 4C is a cross-sectional view taken along line 4 C- 4 C in FIG. 4A .
- step S 40 a top portion of the dielectric structure 160 is removed by a selective etching process, thereby forming an etched space 410 shown in FIGS. 4A-4C .
- the selective etching process may be a wet etching process or a dry etching process performed based on the difference in an etching selectivity between the oxide material and the polysilicon material, such that the dielectric structure 160 is removed while the channel layer 150 is preserved.
- the selective etching process may stop at a desired position by a time mode control.
- FIGS. 5A-5C in which FIG. 5A is a top view of step S 50 of forming the semiconductor structure 100 , FIG. 5B is a cross-sectional view taken along line 5 B- 5 B in FIG. 5A , and FIG. 5C is a cross-sectional view taken along line 5 C- 5 C in FIG. 5A .
- the etched space 410 is then refilled with a material including the same material as that of the channel layer 150 , such as doped polysilicon, to form a conductive plug layer 152 , resulting in a replacement of the top portion of the dielectric structure 160 with the conductive plug layer 152 .
- the conductive plug layer 152 is disposed on the dielectric structure 160 .
- the height HC (shown in FIG. 5B ) of the conductive plug layer 152 on a top surface of the memory structure layer 140 may be larger than the height HD (shown in FIG. 3B ) of the dielectric structure 160 on the top surface of the channel layer 150 before the selective etching process, but the present disclosure is not limited in this regard.
- FIGS. 6A-6C in which FIG. 6A is a top view of step S 60 of forming the semiconductor structure 100 , FIG. 6B is a cross-sectional view taken along line 6 B- 6 B in FIG. 6A , and FIG. 6C is a cross-sectional view taken along line 6 C- 6 C in FIG. 6A .
- step S 60 a portion of the memory structure layer 140 , a portion of the conductive plug layer 152 , and a portion of the channel layer 150 which are exceeded outside the recess 400 are removed by a planarization process such as a chemical-mechanical polishing (CMP) process, such that a top surface 131 of the topmost layer of the dielectric layers 130 is exposed.
- CMP chemical-mechanical polishing
- the memory structure cluster 300 including the memory structure layer 140 , the channel layer 150 , the conductive plug layer 152 , and the dielectric structure 160 is formed over the substrate 110 and through the insulating layers 120 and the dielectric layers 130 , shown in FIGS. 6A-6B .
- a top surface 301 of the memory structure cluster 300 is substantially level with a top surface 131 of the topmost layer of the dielectric layers 130 .
- FIGS. 7A-7D in which FIG. 7A is a top view of step S 70 of forming the semiconductor structure 100 , FIG. 7B is a cross-sectional view taken along line 7 B- 7 B in FIG. 7A , FIG. 7C is a cross-sectional view taken along line 7 C- 7 C in FIG. 7A , and FIG. 7D is a cross-sectional view taken along line 7 D- 7 D in FIG. 7A .
- step S 70 portions of the dielectric layers 130 , portions of the insulating layers 120 , a portion of the channel layer 150 , a portion of the conductive plug layer 152 , and a portion of the dielectric structure 160 are removed by an etching process to form a trench 170 .
- the memory structure cluster 300 is separated into a first memory structure 310 and a second memory structure 320 shown in FIG.
- the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively interconnected with the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the second memory structure 320 , at a bottom of the trench 170 .
- the radius of curvature of the first memory structure 310 is identical to the radius of curvature of the second memory structure 320 , but the present disclosure is not limited in this regard. In other embodiments, the radius of curvature of the first memory structure 310 may be different from the radius of curvature of the second memory structure 320 .
- the etching process stops at an etching stop line L between a top surface 121 and a bottom surface 123 of the bottommost layer of the insulating layers 120 , such that the dielectric structure 160 is exposed from a bottom of the trench 170 , and the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively interconnected with the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the second memory structure 320 .
- the etching stop line L between a top surface 121 and a bottom surface 123 of the bottommost layer of the insulating layers 120 , such that the dielectric structure 160 is exposed from a bottom of the trench 170 , and the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively interconnected with the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the second memory structure 320 .
- the bottommost layer of the insulating layers 120 has the larger thickness, thereby providing additional etching flexibility, such that the etching process can stop at the etching stop line L in time by a time mode control.
- the etching process may be a plasma etching process.
- each of the first memory structure 310 and the second memory structure 320 has a C-shaped cross section complementing each other, and the first memory structure 310 and the second memory structure 320 are bilaterally symmetrical with respect to the trench 170 .
- FIGS. 8A-8F in which FIG. 8A is a top view of step S 80 of forming the semiconductor structure 100 , FIG. 8B is a cross-sectional view taken along line 8 B- 8 B in FIG. 8A , FIG. 8C is a cross-sectional view taken along line 8 C- 8 C in FIG. 8A , FIG. 8D is a cross-sectional view taken along line 8 D- 8 D in FIG. 8A , FIG. 8E is a cross-sectional view taken along line 8 E- 8 E in FIG. 8 A, and FIG. 8F is a cross-sectional view taken along line 8 F- 8 F in FIG. 8E .
- step S 80 the exposed portions of the insulating layers 120 and the exposed portions of the memory storage layer 144 that are exposed from the trench 170 are removed by a selective etching process to respectively form a first group of spaces 180 and a second group of spaces 190 shown in FIGS. 8E-8F , thereby resulting in a structural difference between a portion of the memory structure cluster 300 (including the first memory structure 310 and the second memory structure 320 ) near the trench 170 (shown in FIG. 8E ) and a portion of the memory structure cluster 300 slightly away from the trench (shown in FIG. 8D ). For example, as shown in FIG.
- the insulating layers 120 are preserved between the dielectric layers 130 , and the memory storage layer 144 is also preserved between the blocking layer 142 and the tunneling layer 146 ; on the other hand, as shown in FIG. 8E , the insulating layers 120 and the memory storage layer 144 are both removed to respectively formed the first group of spaces 180 between the dielectric layers 130 and the second group of spaces 190 between the blocking layer 142 and the tunneling layer 146 .
- the first group of spaces 180 are also formed between the insulating layers 120 and the trench 170 .
- the second group of spaces 190 are respectively formed on edges of the first memory structure 310 and the second memory structure 320 and are respectively formed between the trench 170 and the memory storage layer 144 .
- the selective etching process is performed based on the difference in an etching selectivity between the nitride material, the oxide material, and the polysilicon material, such that the exposed portions of the insulating layers 120 and the exposed portions of the memory storage layer 144 are removed while the blocking layer 142 , the tunneling layer 146 , the channel layer 150 , and the dielectric structure 160 are preserved.
- the etching depth DF of the first group of spaces 180 is about the same as the etching depth DS of the second group of spaces 190 , and the etching depth DF, DS may be as deep as about 100 ⁇ , but the present disclosure is not limited in this regard.
- FIGS. 9A-9F in which FIG. 9A is a top view of step S 90 of forming the semiconductor structure 100 , FIG. 9B is a cross-sectional view taken along line 9 B- 9 B in FIG. 9A , FIG. 9C is a cross-sectional view taken along line 9 C- 9 C in FIG. 9A , FIG. 9D is a cross-sectional view taken along line 9 D- 9 D in FIG. 9A , FIG. 9E is a cross-sectional view taken along line 9 E- 9 E in FIG. 9A , and FIG. 9F is a cross-sectional view taken along line 9 F- 9 F in FIG. 9E .
- step S 90 after the removal of the exposed portions of the insulating layers 120 and the exposed portions of the memory storage layer 144 by the selective etching process, the protecting structures 210 are deposited on the first memory structure 310 , the second memory structure 320 , and the topmost layer of the dielectric layers 130 and in the trench 170 .
- the protecting structures 210 are also filled in the first group of spaces 180 and the second group of spaces 190 , shown in FIGS. 9E-9F . Since the width WF of the first group of spaces 180 is larger than the width WS of the second group of spaces 190 , the first group of spaces 180 may not be completely filled with the protecting structures 210 while the second group of spaces 190 is entirely filled with the protecting structures 210 .
- the protecting structures 210 in the first group of spaces 180 may be regarded as thin layers disposed on sidewalls of the blocking layer 142 and the insulating layers 120 .
- the protecting structures 210 may be made of a material including silicon oxide or other dielectric, but the present disclosure is not limited in this regard.
- a structural difference between a portion of the memory structure cluster 300 (including the first memory structure 310 and the second memory structure 320 ) near the trench 170 (shown in FIG. 9E ) and a portion of the memory structure cluster 300 slightly away from the trench (shown in FIG. 9D ) also occurs in this step.
- the insulating layers 120 are preserved between the dielectric layers 130
- the memory storage layer 144 is also preserved between the blocking layer 142 and the tunneling layer 146
- the protecting structures 210 are formed in the first group of spaces 180 (shown in FIG. 8E ) between the dielectric layers 130 and the second group of spaces 190 (shown in FIG. 8E ) between the blocking layer 142 and the tunneling layer 146 .
- FIGS. 10A-10F in which FIG. 10A is a top view of step S 100 of forming the semiconductor structure 100 , FIG. 10B is a cross-sectional view taken along line 10 B- 10 B in FIG. 10A , FIG. 100 is a cross-sectional view taken along line 10 C- 10 C in FIG. 10A , FIG. 10D is a cross-sectional view taken along line 10 D- 10 D in FIG. 10A , FIG. 10E is a cross-sectional view taken along line 10 E- 10 E in FIG. 10A , and FIG. 10F is a cross-sectional view taken along line 10 F- 10 F in FIG. 10E .
- step S 100 the protecting structures 210 on the first memory structure 310 , the second memory structure 320 , the topmost layer of the dielectric layers 130 , and in the trench 170 are removed by a selective etching process. Furthermore, the protecting structures 210 in the first group of spaces 180 are also being entirely removed while the protecting structures 210 in the second group of spaces 190 are being partially removed by the selective etching process, shown in FIGS. 10E-10F .
- the etching process stops when the insulating layers 120 are exposed from the first group of spaces 180 , and since the protecting structures 210 in the first group of spaces 180 are smaller in depth than the protecting structures 210 in the second group of spaces 190 , the protecting structures 210 remain partially in the second group of spaces 190 when the etching process stops.
- the dielectric structure 160 , the blocking layer 142 , and the tunneling layer 146 may also be made of a material including silicon oxide or other dielectric
- the etching process in this step may also be performed on the dielectric structure 160 , the blocking layer 142 , and the tunneling layer 146 , thereby resulting in a partially removal of the dielectric structure 160 , the blocking layer 142 , and the tunneling layer 146 , shown in FIG. 10F .
- the protecting structures 210 are on edges of the first memory structure 310 and the second memory structure 320 and are respectively between the blocking layer 142 and the tunneling layer 146 .
- the protecting structures 210 are disposed between the memory storage layer 144 and the trench 170 and at two ends of the memory storage layer 144 , and adjoin the memory storage layer 144 .
- the second group of spaces 190 may be regarded as concave portions. The concave portions are at opposite two ends of the memory structure layer 140 , and the protecting structures 210 are disposed in the concave portions, respectively.
- FIGS. 11A-11F in which FIG. 11A is a top view of step S 110 of forming the semiconductor structure 100 , FIG. 11B is a cross-sectional view taken along line 11 B- 11 B in FIG. 11A , FIG. 11C is a cross-sectional view taken along line 11 C- 11 C in FIG. 11A , FIG. 11D is a cross-sectional view taken along line 11 D- 11 D in FIG. 11A , FIG. 11E is a cross-sectional view taken along line 11 E- 11 E in FIG. 11A , and FIG. 11F is a cross-sectional view taken along line 11 F- 11 F in FIG. 11E .
- step S 110 the insulating layers 120 between the dielectric layers 130 are then being removed by a selective etching process to form the third group of spaces 200 shown in FIGS. 11D-11F , in which the first group of spaces 180 and the third group of spaces 200 are both between the dielectric layers 130 .
- the selective etching process may be a chemical etching process in hot phosphoric acid removing the insulating layers 120 which may be made of a material including silicon nitride. Since the memory storage layer 144 which may also made of a material including silicon nitride is protected by the protecting structures 210 shown in FIG. 11F , the memory storage layer 144 is not removed during the etching process. As a result, the memory storage layer 144 and the protecting structures 210 may be preserved between the blocking layer 142 and the tunneling layer 146 , shown in FIGS. 11A and 11F .
- FIGS. 12A-12F in which FIG. 12A is a top view of step S 120 of forming the semiconductor structure 100 , FIG. 12B is a cross-sectional view taken along line 12 B- 12 B in FIG. 12A , FIG. 12C is a partial enlargement diagram of FIG. 12B , FIG. 12D is a cross-sectional view taken along line 12 D- 12 D in FIG. 12A , FIG. 12E is a cross-sectional view taken along line 12 E- 12 E in FIG. 12A , and FIG. 12F is a cross-sectional view taken along line 12 F- 12 F in FIG. 12A .
- conductive layers 220 are disposed on a top surface of the semiconductor structure 100 and between the dielectric layers 130 .
- the conductive layers 220 are disposed on the first memory structure 310 , the second memory structure 320 , and the topmost layer of the dielectric layers 130 and in the trench 170 .
- the conductive layers 220 are also being disposed in the first group of spaces 180 (shown in FIG. 11E ) and the third group of spaces 200 (shown in FIG. 11D ) which are between the dielectric layers 130 , thereby resulting in a replacement of the insulating layers 120 with the conductive layers 220 .
- each of the conductive layers 220 includes a barrier layer 222 disposed on each of the dielectric layers 130 and a metal layer 224 disposed on the barrier layer 222 .
- the conductive layers 220 may be disposed by a chemical vapor deposition (CVD) process.
- the barrier layer 222 may be made of a material including titanium nitride
- the metal layer 224 may be made of a material including tungsten or other metal, but the present disclosure is not limited in this regard.
- the manufacturing method of the semiconductor structure 100 provides a method of replacing the insulating layers 120 with the conductive layers 220 while preserving the memory storage layer 144 which is made of the same material as the insulating layers 120 , thereby simplifying the manufacturing process.
- high-k dielectric layers 230 are disposed on the first memory structure 310 , the second memory structure 320 , and the topmost layer of the dielectric layers 130 , in the trench 170 , and between the dielectric layers 130 and the barrier layers 222 , shown in FIG. 12C .
- the high-k dielectric layers 230 may be disposed before the conductive layers 220 are disposed.
- the high-k dielectric layers 230 may be made of a material including aluminum oxide or other dielectric.
- FIGS. 13A-13E in which FIG. 13A is a top view of step S 130 of forming the semiconductor structure 100 , FIG. 13B is a cross-sectional view taken along line 13 B- 13 B in FIG. 13A , FIG. 13C is a cross-sectional view taken along line 13 C- 13 C in FIG. 13A , FIG. 13D is a cross-sectional view taken along line 13 D- 13 D in FIG. 13A , and FIG. 13E is a cross-sectional view taken along line 13 E- 13 E in FIG. 13A .
- step S 130 the high-k dielectric layers 230 and the conductive layers 220 on the first memory structure 310 , the second memory structure 320 , and the topmost layer of the dielectric layers 130 and in the trench 170 are removed by a selective etching process such that the first memory structure 310 and the second memory structure 320 are exposed from the trench 170 .
- a selective etching process such that the first memory structure 310 and the second memory structure 320 are exposed from the trench 170 .
- sidewalls 223 of the conductive layers 220 and the high-k dielectric layers 230 may not be aligned with sidewalls 133 of the dielectric layers 130 ; instead, the sidewalls 233 of the conductive layers 220 and the high-k dielectric layers 230 are etched in a deeper depth to respectively form concave portions 225 between the dielectric layers 130 . This ensures that the conductive layers 220 and the high-k dielectric layers 230 disposed in the trench 170 are completely removed by the selective etching process.
- FIGS. 14A-14E in which FIG. 14A is a top view of step S 140 of forming the semiconductor structure 100 , FIG. 14B is a cross-sectional view taken along line 14 B- 14 B in FIG. 14A , FIG. 14C is a cross-sectional view taken along line 14 C- 14 C in FIG. 14A , FIG. 14D is a cross-sectional view taken along line 14 D- 14 D in FIG. 14A , and FIG. 14E is a cross-sectional view taken along line 14 E- 14 E in FIG. 14A .
- the isolation structure 240 is then filled in the trench 170 and disposed on the first memory structure 310 , the second memory structure 320 , and the topmost layer of the dielectric layers 130 .
- the isolation structure 240 has a T-shaped vertical cross section shown in FIG. 14B-14C . Namely, the isolation structure 240 has a first portion interposed between the first memory structure 310 and the second memory structure 320 and a second portion above the semiconductor structure 100 .
- the semiconductor structure 100 including the memory structure cluster 300 (including the first memory structure 310 and the second memory structure 320 ) of a U-shaped vertical cross section is provided, shown in the FIG. 14A-14B .
- the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively interconnected with the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the second memory structure 320 at a bottom surface 241 of the isolation structure 240 .
- an interlayer dielectric (ILD) layer (not shown in the drawings) may further be disposed on a top surface of the isolation structure 240 , such that a planarization of a top surface of the semiconductor structure 100 may be completed.
- the interlayer dielectric layer may be made of a material including silicon oxide or other dielectric, but the present disclosure is not limited in this regard.
- the manufactured semiconductor structure 100 includes the substrate 110 , the conductive layers 220 , the dielectric layers 130 , the isolation structure 240 , the first memory structure 310 , and the second memory structure 320 .
- the conductive layers 220 and the dielectric layers 130 are interlaced and stacked on the substrate 110 .
- the isolation structure 240 is disposed on the substrate 110 and through the conductive layers 240 and the dielectric layers 130 .
- the first memory structure 310 and the second memory structure 320 are disposed on the substrate 110 , through the conductive layers 220 and the dielectric layers 130 , and on opposite sidewalls 242 , 244 of the isolation structure 240 .
- each of the first memory structure 310 and the second memory structure 320 has a radius of curvature.
- the first memory structure 310 includes the memory structure layer 140 , the channel layer 150 , the dielectric structure 160 , and the protecting structures 210 .
- the second memory structure 320 includes the memory structure layer 140 , the channel layer 150 , the dielectric structure 160 , and the protecting structures 210 .
- the memory structure layer 140 includes the memory storage layer 144 .
- the channel layer 150 is disposed between the memory structure layer 144 and the isolation structure 240 .
- the dielectric structure 160 is disposed between the channel layer 150 and the isolation structure 240 , in which a portion of the channel layer 150 is disposed on a top surface of the dielectric structure 160 .
- the protecting structures 210 are disposed between the memory storage layer 144 and the opposite sidewalls 242 , 244 of the isolation structure 240 and are disposed at two ends of the memory storage layer 144 , in which an etching selectivity to the protecting structures 210 is different from an etching selectivity to the memory storage layer 144 .
- the isolation structure 240 Since the first memory structure 310 and the second memory structure 320 of the semiconductor structure 100 are separated from each other by the isolation structure 240 , the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved. Furthermore, the conductive layers 220 stacked between the dielectric layers 130 can help improve the program speed as well as the erase speed of the semiconductor structure 100 due to the lower resistance.
- FIGS. 15A-15D in which FIG. 15A is a top view of step S 150 of providing a semiconductor device 500 , FIG. 15B is a cross-sectional view taken along line 15 B- 15 B in FIG. 15A , FIG. 15C is a cross-sectional view taken along line 15 C- 15 C in FIG. 15A , and FIG. 15D is a cross-sectional view taken along line 15 D- 15 D in FIG. 15A .
- step S 150 after the semiconductor structure 100 is provided, two contact holes 246 , 248 are then formed in the isolation structure 240 disposed on the memory structure cluster 300 , such that a portion of the channel layer 150 and a portion of the conductive plug layer 152 corresponding to the first memory structure 310 and a portion of the channel layer 150 and a portion of the conductive plug layer 152 corresponding to the second memory structure 320 are respectively exposed from the contact hole 246 and the contact hole 248 .
- two first contact structures 420 , 430 are then respectively formed in the two contact holes 246 , 248 , and electrically connected to the channel layer 150 and the conductive plug layer 152 of the first memory structure 310 and the channel layer 150 and the conductive plug layer 152 of the second memory structure 320 , respectively.
- FIGS. 16A-16D in which FIG. 16A is a top view of step S 160 of providing a semiconductor device 500 , FIG. 16B is a cross-sectional view taken along line 16 B- 16 B in FIG. 16A , FIG. 16C is a cross-sectional view taken along line 16 C- 16 C in FIG. 16A , and FIG. 16D is a cross-sectional view taken along line 16 D- 16 D in FIG. 16A .
- an isolation layer 250 is further formed on the isolation structure 240 , and two second contact structures 440 , 450 are then formed in the isolation layer 250 and respectively electrically connected to the two first contact structures 420 , 430 .
- FIGS. 17A and 17B in which FIG. 17A is a top view of step S 170 of providing a semiconductor device 500 , and FIG. 17B is a cross-sectional view taken along line 17 B- 17 B in FIG. 17A .
- step S 170 multiple semiconductor structures 100 are aligned parallel to each other along the Y axis.
- the isolation structures 240 of the semiconductor structures 100 may be formed continuously along the Y axis.
- the semiconductor structures 100 may be staggered with each other along the X axis.
- FIGS. 18A and 18B in which FIG. 18A is a top view of step S 180 of providing a semiconductor device 500 , and FIG. 18B is a cross-sectional view taken along line 18 B- 18 B in FIG. 18A .
- signal line such as a common source line (CSL) may then be formed to electrically connect to the second contact structures 440 formed on the adjacent semiconductor structures 100 , and the common source line is parallel to the continuously formed isolation structures 240 .
- CSL common source line
- FIG. 19A is a top view of step S 190 of providing a semiconductor device 500
- FIG. 19B is a cross-sectional view taken along line 19 B- 19 B in FIG. 19A
- FIG. 19C is a cross-sectional view taken along line 19 C- 19 C in FIG. 19A
- FIG. 19D is a cross-sectional view taken along line 19 D- 19 D in FIG. 19A
- third contact structures 460 are then electrically connected to the second contact structures 440 / 450 which are not electrically connected to the common source line.
- bit lines (or namely signal lines) may be formed over the common source line and electrically connected to the third contact structures 460 .
- the bit lines are generally orthogonal to the common source line and the continuous isolation structures 240 . After forming the bit lines, the semiconductor device 500 is provided.
- the topmost layers of the conductive layers 220 on the opposite sidewalls 242 , 244 of the isolation structure 240 may respectively function as a ground select line (GSL) and a string select line (SSL), and the semiconductor device 500 is such as a vertical channel type memory device.
- GSL ground select line
- SSL string select line
- FIGS. 20A-20B are the embodiment of the present disclosure of the semiconductor structure 100 a.
- FIGS. 20A and 20B in which FIG. 20A is a top view of step S 200 of forming the semiconductor structure 100 a , and FIG. 20B is a cross-sectional view taken along line 20 B- 20 B in FIG. 20A .
- the semiconductor structure 100 a includes the memory structure cluster 300 without a U-shaped vertical cross section.
- the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively separated from the memory structure layer 140 , the channel layer 150 , and the dielectric structure 160 corresponding to the second memory structure 320 by the isolation structure 240 , and the isolation structure 240 and each of the channel layers 150 are in contact with the substrate 110 .
- each of the channel layers 150 is electrically connected to the circuits configured on the substrate 110 .
- a manufacturing method is further provided.
- the manufacturing method herein is substantially the same as the manufacturing method mentioned above. Some differences occur at forming the recess 400 shown in FIGS. 1A-1B and the trench 170 shown in FIGS. 7A-7C .
- a difference of the manufacturing method herein further includes a step of extending the recess 400 through the memory structure layer 140 after forming the memory structure layer 140 in the recess 400 , such that a portion of the substrate 110 is exposed from a bottom of the recess 400 .
- the channel layer 150 is formed on the memory structure layer 140 and the portion of the substrate 110 .
- the subsequent steps are referred to the manufacturing method mentioned in the aforementioned embodiments. Another difference occurs when coming to the step of forming the trench 170 through the insulating layers 120 , the dielectric layers 130 , and the memory structure cluster 300 .
- the trench 170 herein is formed by removing portions of the insulating layers 120 , portions of the dielectric layers 130 , a portion of the channel layer 150 , a portion of the conductive plug layer 152 , and a portion of the dielectric structure 160 such that the memory structure layer 140 , the channel layer 150 , the conductive plug layer 152 , and the dielectric structure 160 corresponding to the first memory structure 310 are respectively separated from the memory structure layer 140 , the channel layer 150 , the conductive plug layer 152 , and the dielectric structure 160 corresponding to the second memory structure 320 , by the trench 170 and the subsequently disposed isolation structure 240 .
- Each of the channel layers 150 is in contact with the substrate 110 , such that the circuits on the substrate can be electrically connected to the
- FIGS. 21A-21C in which FIG. 21A is a top view of step S 210 of providing a semiconductor device 500 a , FIG. 21B is a cross-sectional view taken along line 21 B- 21 B in FIG. 21A , and FIG. 21C is a cross-sectional view taken along line 21 C- 21 C in FIG. 21A .
- FIGS. 19A-19D there is no common source line formed on the two second contact structures 440 , 450 of the semiconductor structure 100 a , instead, two third contact structures 460 , 470 are formed on both of the second contact structures 440 , 450 , respectively.
- first contact structure 420 , the second contact structure 440 , and the third contact structure 460 corresponding to the first memory structure 310 are respectively staggered with the first contact structure 430 , the second contact structure 450 , and the third contact structure 470 corresponding to the second memory structure 320 .
- Bit lines are formed on semiconductor device 500 a to form a first group of bit lines (BL 1 ) and a second group of bit lines (BL 2 ).
- the first group of bit lines is electrically connected to the third contact structures 460 disposed on the first memory structures 310 while the second group of bit lines is electrically connected to the third contact structures 470 disposed on the second memory structures 320 .
- the substrate 110 may function as a bottom source
- the bottommost layer of the conductive layers 220 is such as a ground select line (GSL)
- the topmost layer of the conductive layers 220 is such as a string select line (SSL)
- the semiconductor device 500 a is such as a vertical channel type memory device.
- the bilaterally symmetrically arranged first memory structure 310 and second memory structure 320 are respectively connected to different bit lines (BL 1 and BL 2 , also signal lines)
- the memory density is increased, and different program/erase operations can be processed simultaneously since different vertical memory structures can be selected via different bit lines simultaneously, and thus the processing speed can be further increased.
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Abstract
Description
- The present disclosure relates to a semiconductor structure and a manufacturing method of the semiconductor structure.
- In recent years, the structures of semiconductor devices have been changed constantly, and the storage capacity of the devices has been increased continuously. Memory devices are used in storage elements for many products such as MP3 players, digital cameras, computer files, etc. As the application increases, the demand for the memory device focuses on small size and large memory capacity. For satisfying the requirement, a memory device having a high element density and a small size and the manufacturing method thereof are in need.
- As such, it is desirable to develop a three-dimensional (3D) memory device with larger number of multiple stacked planes to achieve greater storage capacity, improved qualities, all the while remaining in a small size.
- The disclosure relates in general to a semiconductor structure and a manufacturing method thereof. In the semiconductor structure of the disclosure, a pair of vertical memory structures both have horizontal C-shaped cross sections and are separated from each other by an isolation trench; accordingly, the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved.
- According to an embodiment of the present disclosure, the semiconductor structure includes a substrate, a plurality of conductive layers, a plurality of dielectric layers, an isolation structure, a first memory structure, and a second memory structure. The conductive layers and the dielectric layers are interlaced and stacked on the substrate. The isolation structure is disposed on the substrate and through the conductive layers and the dielectric layers. Each of the first memory structure and the second memory structure has a radius of curvature. The first memory structure and the second memory structure penetrate through the conductive layers and the dielectric layers are disposed on opposite sidewalls of the isolation structure. Each of the first memory structure and the second memory structure includes a memory structure layer, a channel layer, and at least two protecting structures. The memory structure layer includes a memory storage layer. The channel layer is disposed between the memory structure layer and the isolation structure. The protecting structures are disposed at two ends of the memory storage layer, in which an etching selectivity to the protecting structures is different from an etching selectivity to the memory storage layer.
- In an embodiment of the present disclosure, the memory structure layer further includes a blocking layer and a tunneling layer. The blocking layer is disposed on sidewalls of the conductive layers and the dielectric layers. The memory storage layer is disposed between the blocking layer and the tunneling layer. The protecting structures are disposed between the blocking layer and the tunneling layer and adjoin the memory storage layer.
- In an embodiment of the present disclosure, each of the first memory structure and the second memory structure further includes a dielectric structure and a conductive plug layer, the dielectric structure is disposed between the channel layer and the isolation structure, and the conductive plug layer is disposed on the dielectric structure.
- In an embodiment of the present disclosure, each of the conductive layers further includes a barrier layer and a metal layer disposed on the barrier layer.
- In an embodiment of the present disclosure, the semiconductor structure further includes a plurality of high-k dielectric layers disposed between the dielectric layers and the barrier layers, respectively.
- In an embodiment of the present disclosure, the memory structure layer and the channel layer corresponding to the first memory structure are respectively interconnected with the memory structure layer and the channel layer corresponding to the second memory structure at a bottom surface of the isolation structure.
- In an embodiment of the present disclosure, the memory structure layer and the channel layer corresponding to the first memory structure are respectively separated from the memory structure layer and the channel layer corresponding to the second memory structure by the isolation structure.
- In an embodiment of the present disclosure, each of the channel layers is in contact with the substrate.
- In an embodiment of the present disclosure, the semiconductor structure further includes two contact structures, each electrically connected to the first memory structure and the second memory structure.
- In an embodiment of the present disclosure, the semiconductor structure further includes at least a signal line interconnecting the corresponding one of the conductive structures.
- In an embodiment of the present disclosure, the semiconductor structure further includes two signal lines connecting to the conductive structures, respectively.
- According to an embodiment of the present disclosure, the manufacturing method of the semiconductor structure includes the following steps of: forming a plurality of insulating layers and a plurality of dielectric layers on a substrate, in which the insulating layers and the dielectric layers are interlaced and stacked on the substrate; forming a memory structure cluster on the substrate and through the insulating layers and the dielectric layers, in which the memory structure cluster includes a channel layer, a conductive plug layer, and a memory structure layer including a memory storage layer; forming a trench through the insulating layers, the dielectric layers, and the memory structure cluster, such that the memory structure cluster is separated into a first memory structure and a second memory structure, and portions of the insulating layers and portions of the memory storage layer are exposed from the trench; removing the exposed portions of the insulating layers and the exposed portions of the memory storage layer to respectively form a first group of spaces and a second group of spaces; filling a plurality of protecting structures in the first group of spaces and the second group of spaces; removing portions of the protecting structures such that the insulating layers are exposed from the first group of spaces; replacing the insulating layers with a plurality of conductive layers.
- In an embodiment of the present disclosure, replacing the insulating layers with the conductive layers includes: removing the insulating layers, after the insulating layers are exposed, to form a third group of spaces between the dielectric layers; filling a plurality of conductive layers in the first group of spaces and the third group of spaces.
- In an embodiment of the present disclosure, the manufacturing method of the semiconductor structure further includes: forming an isolation structure in the trench and on the memory structure cluster and a topmost layer of the dielectric layers after filling the conductive layers in the first group of spaces and the third group of spaces.
- In an embodiment of the present disclosure, the memory structure cluster further includes a dielectric structure, the tunneling layer is disposed between the dielectric structure and the memory structure layer, and forming the memory structure cluster on the substrate and through the insulating layers and the dielectric layers includes: forming a recess with an elliptical profile, in which the recess penetrates the insulating layers and the dielectric layers; forming the memory structure layer in the recess and on the topmost layer of the dielectric layers; forming the channel layer on the memory structure layer; forming the dielectric structure on the channel layer to fill the recess; replacing a top portion of the dielectric structure with the conductive plug layer; removing a portion of the memory structure layer, a portion of the conductive plug layer, and a portion of the channel layer which are exceeded outside the recess.
- In an embodiment of the present disclosure, forming the trench through the insulating layers, the dielectric layers, and the memory structure cluster includes: removing portions of the insulating layers, portions of the dielectric layers, a portion of the channel layer, and a portion of the conductive plug layer, such that the memory structure layer and the channel layer corresponding to the first memory structure are respectively interconnected with the memory structure layer, the channel layer, and the dielectric structure corresponding to the second memory structure at a bottom of the trench.
- In an embodiment of the present disclosure, forming the trench through the insulating layers, the dielectric layers, and the memory structure cluster includes: removing portions of the insulating layers, portions of the dielectric layers, a portion of the channel layer, and a portion of the conductive plug layer, such that the memory structure layer and the channel layer corresponding to the first memory structure are respectively separated from the memory structure layer and the channel layer corresponding to the second memory structure by the trench.
- In an embodiment of the present disclosure, the manufacturing method of the semiconductor structure further includes: forming an isolation layer on the memory structure cluster and the topmost layer of the dielectric layers; forming two contact structures, each electrically connected to the first memory structure and the second memory structure.
- In the aforementioned embodiments of the present disclosure, the first memory structure and the second memory structure are separated from each other by the isolation structure, such that the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved. Furthermore, the conductive layers stacked between the dielectric layers can help improve the program speed as well as the erase speed of the semiconductor structure due to the lower resistance. Moreover, the aforementioned embodiments of the present disclosure also provide a method of replacing the insulating layers with the conductive layers while preserving the memory storage layer which is made of the same material as the insulating layers, thereby simplifying the process of manufacturing the semiconductor structure.
- The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows:
-
FIGS. 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A, 13A, and 14A are top views of a process at various stages of a manufacturing method of a semiconductor structure according to an embodiment of the present disclosure; -
FIGS. 1B, 2B, 3B-3C, 4B-4C, 5B-5C, 6B-6C, 7B-7D, 8B-8F, 9B-9F, 10B-10F, 11B-11F, 12B , 12D-12F, 13B-13E, and 14B-14E are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor structure according to an embodiment of the present disclosure; -
FIG. 12C is a partial enlargement diagram ofFIG. 12B ; -
FIGS. 15A, 16A, 17A, 18A and 19A are top views of a process at various stages of a manufacturing method of a semiconductor device according to an embodiment of the present disclosure; -
FIGS. 15B-15D, 16B-16D, 17B, 18B, 19B-19D are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor device according to an embodiment of the present disclosure; -
FIG. 20A is a top view of a process at various stages of a manufacturing method of a semiconductor structure according to another embodiment of the present disclosure; -
FIG. 20B is a cross-sectional view of a process at various stages of a manufacturing method of a semiconductor structure according to another embodiment of the present disclosure; -
FIG. 21A is a top view of a process at various stages of a manufacturing method of a semiconductor device according to another embodiment of the present disclosure; and -
FIGS. 21B-21C are cross-sectional views of a process at various stages of a manufacturing method of a semiconductor device according to another embodiment of the present disclosure. - Reference will now be made in detail to the present embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
- In the embodiments of the present disclosure, a semiconductor structure and a method of manufacturing the same are provided. For the purpose of simplicity and clarity, the method of manufacturing the semiconductor structure will be discussed first in the article. Furthermore, the term “top view” may be used herein for ease of description to refer to as a cross-sectional view of a topmost layer of the semiconductor structure in order to highlight the technical features of the inventive concept. Besides, some of the secondary elements may be omitted in the drawings accompanying the following embodiments.
-
FIGS. 1A-1B, 2A-2B, 3A-3C, 4A-4C, 5A-5C, 6A-6C, 7A-7D, 8A-8F, 9A-9F, 10A-10F, 11A -11F, 12A-12F, 13A-13E, and 14A-14E are views of a process at various stages of a manufacturing method of asemiconductor structure 100 according to an embodiment of the present disclosure. For the purpose of simplicity and clarity, the elements covered beneath in thesemiconductor structure 100 are illustrated in solid lines in the drawings. - Reference is made to
FIGS. 1A and 1B , in whichFIG. 1A is a top view of step S10 of forming thesemiconductor structure 100, andFIG. 1B is a cross-sectional view taken alongline 1B-1B inFIG. 1A . In step S10, asubstrate 110 is provided, and a plurality of insulatinglayers 120 and a plurality ofdielectric layers 130 are interlaced and stacked on thesubstrate 110. After the stacked layers are provided on thesubstrate 110, arecess 400 is then formed. Therecess 400 penetrates through the insulatinglayers 120 and thedielectric layers 130 and stops below a bottommost layer of the insulating layers 120. As shown inFIG. 1A , therecess 400 has an elliptical profile, in a top view, and the long axis (the longer diameter) of the elliptical cross section may be as long as about 150 nm. In some embodiments of the present disclosure, a thickness T of the bottommost layer of the insulatinglayers 120 may be larger than a thickness of other layers of the insulating layers 120. - Reference is made to
FIGS. 2A and 2B , in whichFIG. 2A is a top view of step S20 of forming thesemiconductor structure 100, andFIG. 2B is a cross-sectional view taken alongline 2B-2B inFIG. 2A . In step S20, amemory structure layer 140 is conformally formed in therecess 400 and on a topmost layer of thedielectric layers 130, and achannel layer 150 is then conformally formed on thememory structure layer 140. Thememory structure layer 140 includes ablocking layer 142, amemory storage layer 144, and atunneling layer 146. Theblocking layer 142 is disposed on sidewalls of the insulatinglayers 120 and thedielectric layers 130 and the topmost layer of thedielectric layers 130, thememory storage layer 144 is disposed on theblocking layer 142, and thetunneling layer 146 is disposed on thememory storage layer 144. In some embodiments of the present disclosure, theblocking layer 142 and thetunneling layer 146 may be made of a material including silicon oxide or other dielectric, thememory storage layer 144 may be made of a material including silicon nitride or other material that is able to trap electrons, and thechannel layer 150 may be made of a material including undoped polysilicon, but the present disclosure is not limited in this regard. - Reference is made to
FIGS. 3A-3C , in whichFIG. 3A is a top view of step S30 of forming thesemiconductor structure 100,FIG. 3B is a cross-sectional view taken alongline 3B-3B inFIG. 3A , andFIG. 3C is a cross-sectional view taken alongline 3C-3C inFIG. 3A . In step S30, adielectric structure 160 is disposed on thechannel layer 150 to fill therecess 400 and formed over the topmost layer of the dielectric layers 130. A portion of thedielectric structure 160 which is formed over the topmost layer of thedielectric layers 130 is higher than a top surface of thechannel layer 150 by a height HD. In some embodiments of the present disclosure, thedielectric structure 160 may be made of a material including silicon oxide or other dielectric. - Reference is made to
FIGS. 4A-4C , in whichFIG. 4A is a top view of step S40 of forming thesemiconductor structure 100,FIG. 4B is a cross-sectional view taken alongline 4B-4B inFIG. 4A , andFIG. 4C is a cross-sectional view taken alongline 4C-4C inFIG. 4A . In step S40, a top portion of thedielectric structure 160 is removed by a selective etching process, thereby forming an etchedspace 410 shown inFIGS. 4A-4C . The selective etching process may be a wet etching process or a dry etching process performed based on the difference in an etching selectivity between the oxide material and the polysilicon material, such that thedielectric structure 160 is removed while thechannel layer 150 is preserved. As for the etching depth of thedielectric structure 160 in therecess 400, the selective etching process may stop at a desired position by a time mode control. - Reference is made to
FIGS. 5A-5C , in whichFIG. 5A is a top view of step S50 of forming thesemiconductor structure 100,FIG. 5B is a cross-sectional view taken alongline 5B-5B inFIG. 5A , andFIG. 5C is a cross-sectional view taken along line 5C-5C inFIG. 5A . In step S50, the etchedspace 410 is then refilled with a material including the same material as that of thechannel layer 150, such as doped polysilicon, to form aconductive plug layer 152, resulting in a replacement of the top portion of thedielectric structure 160 with theconductive plug layer 152. As a result, theconductive plug layer 152 is disposed on thedielectric structure 160. In some embodiments of the present disclosure, the height HC (shown inFIG. 5B ) of theconductive plug layer 152 on a top surface of thememory structure layer 140 may be larger than the height HD (shown inFIG. 3B ) of thedielectric structure 160 on the top surface of thechannel layer 150 before the selective etching process, but the present disclosure is not limited in this regard. - Reference is made to
FIGS. 6A-6C , in whichFIG. 6A is a top view of step S60 of forming thesemiconductor structure 100,FIG. 6B is a cross-sectional view taken alongline 6B-6B inFIG. 6A , andFIG. 6C is a cross-sectional view taken alongline 6C-6C inFIG. 6A . In step S60, a portion of thememory structure layer 140, a portion of theconductive plug layer 152, and a portion of thechannel layer 150 which are exceeded outside therecess 400 are removed by a planarization process such as a chemical-mechanical polishing (CMP) process, such that atop surface 131 of the topmost layer of thedielectric layers 130 is exposed. After the planarization process, thememory structure cluster 300 including thememory structure layer 140, thechannel layer 150, theconductive plug layer 152, and thedielectric structure 160 is formed over thesubstrate 110 and through the insulatinglayers 120 and thedielectric layers 130, shown inFIGS. 6A-6B . In some embodiments of the present disclosure, atop surface 301 of thememory structure cluster 300 is substantially level with atop surface 131 of the topmost layer of the dielectric layers 130. - Reference is made to
FIGS. 7A-7D , in whichFIG. 7A is a top view of step S70 of forming thesemiconductor structure 100,FIG. 7B is a cross-sectional view taken alongline 7B-7B inFIG. 7A ,FIG. 7C is a cross-sectional view taken alongline 7C-7C inFIG. 7A , andFIG. 7D is a cross-sectional view taken alongline 7D-7D inFIG. 7A . In step S70, portions of thedielectric layers 130, portions of the insulatinglayers 120, a portion of thechannel layer 150, a portion of theconductive plug layer 152, and a portion of thedielectric structure 160 are removed by an etching process to form atrench 170. After thetrench 170 is formed, thememory structure cluster 300 is separated into afirst memory structure 310 and asecond memory structure 320 shown inFIG. 7A , such that portions of the insulatinglayers 120, portions of thedielectric layers 130, portions of the memory structure layer 140 (including theblocking layer 142, thememory storage layer 144, and the tunneling layer 146), portions ofchannel layer 150, a portion of theconductive plug layer 152, and portions ofdielectric structure 160 are exposed from thetrench 170. As a result, thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thefirst memory structure 310 are respectively interconnected with thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thesecond memory structure 320, at a bottom of thetrench 170. In the present embodiment, the radius of curvature of thefirst memory structure 310 is identical to the radius of curvature of thesecond memory structure 320, but the present disclosure is not limited in this regard. In other embodiments, the radius of curvature of thefirst memory structure 310 may be different from the radius of curvature of thesecond memory structure 320. - As shown in
FIGS. 7A-7C , the etching process stops at an etching stop line L between atop surface 121 and abottom surface 123 of the bottommost layer of the insulatinglayers 120, such that thedielectric structure 160 is exposed from a bottom of thetrench 170, and thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thefirst memory structure 310 are respectively interconnected with thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thesecond memory structure 320. In some embodiments, as mentioned inFIG. 1B , the bottommost layer of the insulatinglayers 120 has the larger thickness, thereby providing additional etching flexibility, such that the etching process can stop at the etching stop line L in time by a time mode control. In some embodiments of the present disclosure, the etching process may be a plasma etching process. Furthermore, each of thefirst memory structure 310 and thesecond memory structure 320 has a C-shaped cross section complementing each other, and thefirst memory structure 310 and thesecond memory structure 320 are bilaterally symmetrical with respect to thetrench 170. - Reference is made to
FIGS. 8A-8F , in whichFIG. 8A is a top view of step S80 of forming thesemiconductor structure 100,FIG. 8B is a cross-sectional view taken alongline 8B-8B inFIG. 8A ,FIG. 8C is a cross-sectional view taken alongline 8C-8C inFIG. 8A ,FIG. 8D is a cross-sectional view taken alongline 8D-8D inFIG. 8A ,FIG. 8E is a cross-sectional view taken alongline 8E-8E in FIG. 8A, andFIG. 8F is a cross-sectional view taken alongline 8F-8F inFIG. 8E . In step S80, the exposed portions of the insulatinglayers 120 and the exposed portions of thememory storage layer 144 that are exposed from thetrench 170 are removed by a selective etching process to respectively form a first group ofspaces 180 and a second group ofspaces 190 shown inFIGS. 8E-8F , thereby resulting in a structural difference between a portion of the memory structure cluster 300 (including thefirst memory structure 310 and the second memory structure 320) near the trench 170 (shown inFIG. 8E ) and a portion of thememory structure cluster 300 slightly away from the trench (shown inFIG. 8D ). For example, as shown inFIG. 8D , the insulatinglayers 120 are preserved between thedielectric layers 130, and thememory storage layer 144 is also preserved between theblocking layer 142 and thetunneling layer 146; on the other hand, as shown inFIG. 8E , the insulatinglayers 120 and thememory storage layer 144 are both removed to respectively formed the first group ofspaces 180 between thedielectric layers 130 and the second group ofspaces 190 between theblocking layer 142 and thetunneling layer 146. - As shown in
FIGS. 8A and 8F , the first group ofspaces 180 are also formed between the insulatinglayers 120 and thetrench 170. Furthermore, the second group ofspaces 190 are respectively formed on edges of thefirst memory structure 310 and thesecond memory structure 320 and are respectively formed between thetrench 170 and thememory storage layer 144. For example, the selective etching process is performed based on the difference in an etching selectivity between the nitride material, the oxide material, and the polysilicon material, such that the exposed portions of the insulatinglayers 120 and the exposed portions of thememory storage layer 144 are removed while theblocking layer 142, thetunneling layer 146, thechannel layer 150, and thedielectric structure 160 are preserved. In some embodiments of the present disclosure, the etching depth DF of the first group ofspaces 180 is about the same as the etching depth DS of the second group ofspaces 190, and the etching depth DF, DS may be as deep as about 100 Å, but the present disclosure is not limited in this regard. - Reference is made to
FIGS. 9A-9F , in whichFIG. 9A is a top view of step S90 of forming thesemiconductor structure 100,FIG. 9B is a cross-sectional view taken alongline 9B-9B inFIG. 9A ,FIG. 9C is a cross-sectional view taken alongline 9C-9C inFIG. 9A ,FIG. 9D is a cross-sectional view taken alongline 9D-9D inFIG. 9A ,FIG. 9E is a cross-sectional view taken alongline 9E-9E inFIG. 9A , andFIG. 9F is a cross-sectional view taken alongline 9F-9F inFIG. 9E . In step S90, after the removal of the exposed portions of the insulatinglayers 120 and the exposed portions of thememory storage layer 144 by the selective etching process, the protectingstructures 210 are deposited on thefirst memory structure 310, thesecond memory structure 320, and the topmost layer of thedielectric layers 130 and in thetrench 170. The protectingstructures 210 are also filled in the first group ofspaces 180 and the second group ofspaces 190, shown inFIGS. 9E-9F . Since the width WF of the first group ofspaces 180 is larger than the width WS of the second group ofspaces 190, the first group ofspaces 180 may not be completely filled with the protectingstructures 210 while the second group ofspaces 190 is entirely filled with the protectingstructures 210. In other words, as shown inFIG. 9F , the protectingstructures 210 in the first group ofspaces 180 may be regarded as thin layers disposed on sidewalls of theblocking layer 142 and the insulating layers 120. In some embodiments of the present disclosure, the protectingstructures 210 may be made of a material including silicon oxide or other dielectric, but the present disclosure is not limited in this regard. - Similar to the step S80 previously discussed, a structural difference between a portion of the memory structure cluster 300 (including the
first memory structure 310 and the second memory structure 320) near the trench 170 (shown inFIG. 9E ) and a portion of thememory structure cluster 300 slightly away from the trench (shown inFIG. 9D ) also occurs in this step. Namely, as shown inFIG. 9D , the insulatinglayers 120 are preserved between thedielectric layers 130, and thememory storage layer 144 is also preserved between theblocking layer 142 and thetunneling layer 146; on the other hand, as shown inFIG. 9E , the protectingstructures 210 are formed in the first group of spaces 180 (shown inFIG. 8E ) between thedielectric layers 130 and the second group of spaces 190 (shown inFIG. 8E ) between theblocking layer 142 and thetunneling layer 146. - Reference is made to
FIGS. 10A-10F , in whichFIG. 10A is a top view of step S100 of forming thesemiconductor structure 100,FIG. 10B is a cross-sectional view taken alongline 10B-10B inFIG. 10A ,FIG. 100 is a cross-sectional view taken alongline 10C-10C inFIG. 10A ,FIG. 10D is a cross-sectional view taken alongline 10D-10D inFIG. 10A ,FIG. 10E is a cross-sectional view taken alongline 10E-10E inFIG. 10A , andFIG. 10F is a cross-sectional view taken alongline 10F-10F inFIG. 10E . In step S100, the protectingstructures 210 on thefirst memory structure 310, thesecond memory structure 320, the topmost layer of thedielectric layers 130, and in thetrench 170 are removed by a selective etching process. Furthermore, the protectingstructures 210 in the first group ofspaces 180 are also being entirely removed while the protectingstructures 210 in the second group ofspaces 190 are being partially removed by the selective etching process, shown inFIGS. 10E-10F . In some embodiments, the etching process stops when the insulatinglayers 120 are exposed from the first group ofspaces 180, and since the protectingstructures 210 in the first group ofspaces 180 are smaller in depth than the protectingstructures 210 in the second group ofspaces 190, the protectingstructures 210 remain partially in the second group ofspaces 190 when the etching process stops. Moreover, since thedielectric structure 160, theblocking layer 142, and thetunneling layer 146 may also be made of a material including silicon oxide or other dielectric, the etching process in this step may also be performed on thedielectric structure 160, theblocking layer 142, and thetunneling layer 146, thereby resulting in a partially removal of thedielectric structure 160, theblocking layer 142, and thetunneling layer 146, shown inFIG. 10F . - As a result, as shown in
FIGS. 10A and 10F , the protectingstructures 210 are on edges of thefirst memory structure 310 and thesecond memory structure 320 and are respectively between theblocking layer 142 and thetunneling layer 146. In other words, the protectingstructures 210 are disposed between thememory storage layer 144 and thetrench 170 and at two ends of thememory storage layer 144, and adjoin thememory storage layer 144. In detail, since the second group ofspaces 190 are formed between theblocking layer 142 and thetunneling layer 146, the second group ofspaces 190 may be regarded as concave portions. The concave portions are at opposite two ends of thememory structure layer 140, and the protectingstructures 210 are disposed in the concave portions, respectively. - Reference is made to
FIGS. 11A-11F , in whichFIG. 11A is a top view of step S110 of forming thesemiconductor structure 100,FIG. 11B is a cross-sectional view taken alongline 11B-11B inFIG. 11A ,FIG. 11C is a cross-sectional view taken alongline 11C-11C inFIG. 11A ,FIG. 11D is a cross-sectional view taken alongline 11D-11D inFIG. 11A ,FIG. 11E is a cross-sectional view taken alongline 11E-11E inFIG. 11A , andFIG. 11F is a cross-sectional view taken alongline 11F-11F inFIG. 11E . In step S110, the insulatinglayers 120 between thedielectric layers 130 are then being removed by a selective etching process to form the third group ofspaces 200 shown inFIGS. 11D-11F , in which the first group ofspaces 180 and the third group ofspaces 200 are both between the dielectric layers 130. In some embodiments of the present disclosure, the selective etching process may be a chemical etching process in hot phosphoric acid removing the insulatinglayers 120 which may be made of a material including silicon nitride. Since thememory storage layer 144 which may also made of a material including silicon nitride is protected by the protectingstructures 210 shown inFIG. 11F , thememory storage layer 144 is not removed during the etching process. As a result, thememory storage layer 144 and the protectingstructures 210 may be preserved between theblocking layer 142 and thetunneling layer 146, shown inFIGS. 11A and 11F . - Reference is made to
FIGS. 12A-12F , in whichFIG. 12A is a top view of step S120 of forming thesemiconductor structure 100,FIG. 12B is a cross-sectional view taken alongline 12B-12B inFIG. 12A ,FIG. 12C is a partial enlargement diagram ofFIG. 12B ,FIG. 12D is a cross-sectional view taken alongline 12D-12D inFIG. 12A ,FIG. 12E is a cross-sectional view taken alongline 12E-12E inFIG. 12A , andFIG. 12F is a cross-sectional view taken alongline 12F-12F inFIG. 12A . In step S120, after the removal of the insulatinglayers 120 by the selective etching process,conductive layers 220 are disposed on a top surface of thesemiconductor structure 100 and between the dielectric layers 130. For example, theconductive layers 220 are disposed on thefirst memory structure 310, thesecond memory structure 320, and the topmost layer of thedielectric layers 130 and in thetrench 170. Furthermore, as shown inFIGS. 12B-12F , theconductive layers 220 are also being disposed in the first group of spaces 180 (shown inFIG. 11E ) and the third group of spaces 200 (shown inFIG. 11D ) which are between thedielectric layers 130, thereby resulting in a replacement of the insulatinglayers 120 with theconductive layers 220. As shown inFIG. 12C , each of theconductive layers 220 includes a barrier layer 222 disposed on each of thedielectric layers 130 and a metal layer 224 disposed on the barrier layer 222. Theconductive layers 220 may be disposed by a chemical vapor deposition (CVD) process. In some embodiments of the present disclosure, the barrier layer 222 may be made of a material including titanium nitride, and the metal layer 224 may be made of a material including tungsten or other metal, but the present disclosure is not limited in this regard. - In the aforementioned embodiments of the present disclosure, the manufacturing method of the
semiconductor structure 100 provides a method of replacing the insulatinglayers 120 with theconductive layers 220 while preserving thememory storage layer 144 which is made of the same material as the insulatinglayers 120, thereby simplifying the manufacturing process. - In some embodiments of the present disclosure, high-k dielectric layers 230 are disposed on the
first memory structure 310, thesecond memory structure 320, and the topmost layer of thedielectric layers 130, in thetrench 170, and between thedielectric layers 130 and the barrier layers 222, shown inFIG. 12C . For example, the high-k dielectric layers 230 may be disposed before theconductive layers 220 are disposed. Furthermore, the high-k dielectric layers 230 may be made of a material including aluminum oxide or other dielectric. - Reference is made to
FIGS. 13A-13E , in whichFIG. 13A is a top view of step S130 of forming thesemiconductor structure 100,FIG. 13B is a cross-sectional view taken alongline 13B-13B inFIG. 13A ,FIG. 13C is a cross-sectional view taken alongline 13C-13C inFIG. 13A ,FIG. 13D is a cross-sectional view taken alongline 13D-13D inFIG. 13A , andFIG. 13E is a cross-sectional view taken alongline 13E-13E inFIG. 13A . In step S130, the high-k dielectric layers 230 and theconductive layers 220 on thefirst memory structure 310, thesecond memory structure 320, and the topmost layer of thedielectric layers 130 and in thetrench 170 are removed by a selective etching process such that thefirst memory structure 310 and thesecond memory structure 320 are exposed from thetrench 170. In some embodiments of the present disclosure, as shown inFIG. 13C , sidewalls 223 of theconductive layers 220 and the high-k dielectric layers 230 may not be aligned withsidewalls 133 of thedielectric layers 130; instead, the sidewalls 233 of theconductive layers 220 and the high-k dielectric layers 230 are etched in a deeper depth to respectively formconcave portions 225 between the dielectric layers 130. This ensures that theconductive layers 220 and the high-k dielectric layers 230 disposed in thetrench 170 are completely removed by the selective etching process. - Reference is made to
FIGS. 14A-14E , in whichFIG. 14A is a top view of step S140 of forming thesemiconductor structure 100,FIG. 14B is a cross-sectional view taken alongline 14B-14B inFIG. 14A ,FIG. 14C is a cross-sectional view taken alongline 14C-14C inFIG. 14A ,FIG. 14D is a cross-sectional view taken alongline 14D-14D inFIG. 14A , andFIG. 14E is a cross-sectional view taken alongline 14E-14E inFIG. 14A . In step S140, theisolation structure 240 is then filled in thetrench 170 and disposed on thefirst memory structure 310, thesecond memory structure 320, and the topmost layer of the dielectric layers 130. Theisolation structure 240 has a T-shaped vertical cross section shown inFIG. 14B-14C . Namely, theisolation structure 240 has a first portion interposed between thefirst memory structure 310 and thesecond memory structure 320 and a second portion above thesemiconductor structure 100. After theisolation structure 240 is disposed, thesemiconductor structure 100 including the memory structure cluster 300 (including thefirst memory structure 310 and the second memory structure 320) of a U-shaped vertical cross section is provided, shown in theFIG. 14A-14B . In some embodiments of the present disclosure, thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thefirst memory structure 310 are respectively interconnected with thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thesecond memory structure 320 at abottom surface 241 of theisolation structure 240. In some other embodiments of the present disclosure, an interlayer dielectric (ILD) layer (not shown in the drawings) may further be disposed on a top surface of theisolation structure 240, such that a planarization of a top surface of thesemiconductor structure 100 may be completed. The interlayer dielectric layer may be made of a material including silicon oxide or other dielectric, but the present disclosure is not limited in this regard. - In the aforementioned embodiments of the present disclosure, the manufactured
semiconductor structure 100 includes thesubstrate 110, theconductive layers 220, thedielectric layers 130, theisolation structure 240, thefirst memory structure 310, and thesecond memory structure 320. Theconductive layers 220 and thedielectric layers 130 are interlaced and stacked on thesubstrate 110. Theisolation structure 240 is disposed on thesubstrate 110 and through theconductive layers 240 and the dielectric layers 130. Thefirst memory structure 310 and thesecond memory structure 320 are disposed on thesubstrate 110, through theconductive layers 220 and thedielectric layers 130, and onopposite sidewalls isolation structure 240. Furthermore, each of thefirst memory structure 310 and thesecond memory structure 320 has a radius of curvature. Thefirst memory structure 310 includes thememory structure layer 140, thechannel layer 150, thedielectric structure 160, and the protectingstructures 210. Thesecond memory structure 320 includes thememory structure layer 140, thechannel layer 150, thedielectric structure 160, and the protectingstructures 210. Thememory structure layer 140 includes thememory storage layer 144. Thechannel layer 150 is disposed between thememory structure layer 144 and theisolation structure 240. Thedielectric structure 160 is disposed between thechannel layer 150 and theisolation structure 240, in which a portion of thechannel layer 150 is disposed on a top surface of thedielectric structure 160. The protectingstructures 210 are disposed between thememory storage layer 144 and theopposite sidewalls isolation structure 240 and are disposed at two ends of thememory storage layer 144, in which an etching selectivity to the protectingstructures 210 is different from an etching selectivity to thememory storage layer 144. - Since the
first memory structure 310 and thesecond memory structure 320 of thesemiconductor structure 100 are separated from each other by theisolation structure 240, the memory density in a unit area is increased, and hence a greater memory storage capacity is achieved. Furthermore, theconductive layers 220 stacked between thedielectric layers 130 can help improve the program speed as well as the erase speed of thesemiconductor structure 100 due to the lower resistance. - It is to be noted that the connection relationships, the materials, and the advantages of the elements described above will not be repeated in the following description. In the following description, further details of providing a
semiconductor device 500 by processing the manufacturedsemiconductor structure 100 will be discussed. - Reference is made to
FIGS. 15A-15D , in whichFIG. 15A is a top view of step S150 of providing asemiconductor device 500,FIG. 15B is a cross-sectional view taken alongline 15B-15B inFIG. 15A ,FIG. 15C is a cross-sectional view taken alongline 15C-15C inFIG. 15A , andFIG. 15D is a cross-sectional view taken alongline 15D-15D inFIG. 15A . In step S150, after thesemiconductor structure 100 is provided, twocontact holes isolation structure 240 disposed on thememory structure cluster 300, such that a portion of thechannel layer 150 and a portion of theconductive plug layer 152 corresponding to thefirst memory structure 310 and a portion of thechannel layer 150 and a portion of theconductive plug layer 152 corresponding to thesecond memory structure 320 are respectively exposed from thecontact hole 246 and thecontact hole 248. Next, twofirst contact structures contact holes channel layer 150 and theconductive plug layer 152 of thefirst memory structure 310 and thechannel layer 150 and theconductive plug layer 152 of thesecond memory structure 320, respectively. - Reference is made to
FIGS. 16A-16D , in whichFIG. 16A is a top view of step S160 of providing asemiconductor device 500,FIG. 16B is a cross-sectional view taken alongline 16B-16B inFIG. 16A ,FIG. 16C is a cross-sectional view taken alongline 16C-16C inFIG. 16A , andFIG. 16D is a cross-sectional view taken alongline 16D-16D inFIG. 16A . In step S160, anisolation layer 250 is further formed on theisolation structure 240, and twosecond contact structures isolation layer 250 and respectively electrically connected to the twofirst contact structures - Reference is made to
FIGS. 17A and 17B , in whichFIG. 17A is a top view of step S170 of providing asemiconductor device 500, andFIG. 17B is a cross-sectional view taken alongline 17B-17B inFIG. 17A . In step S170,multiple semiconductor structures 100 are aligned parallel to each other along the Y axis. In other words, theisolation structures 240 of thesemiconductor structures 100 may be formed continuously along the Y axis. Furthermore, thesemiconductor structures 100 may be staggered with each other along the X axis. - Reference is made to
FIGS. 18A and 18B , in whichFIG. 18A is a top view of step S180 of providing asemiconductor device 500, andFIG. 18B is a cross-sectional view taken alongline 18B-18B inFIG. 18A . In step S180, signal line such as a common source line (CSL) may then be formed to electrically connect to thesecond contact structures 440 formed on theadjacent semiconductor structures 100, and the common source line is parallel to the continuously formedisolation structures 240. - Reference is made to
FIGS. 19A-19D , in whichFIG. 19A is a top view of step S190 of providing asemiconductor device 500,FIG. 19B is a cross-sectional view taken alongline 19B-19B inFIG. 19A ,FIG. 19C is a cross-sectional view taken alongline 19C-19C inFIG. 19A , andFIG. 19D is a cross-sectional view taken alongline 19D-19D inFIG. 19A . In step S190,third contact structures 460 are then electrically connected to thesecond contact structures 440/450 which are not electrically connected to the common source line. Next, bit lines (or namely signal lines) may be formed over the common source line and electrically connected to thethird contact structures 460. The bit lines are generally orthogonal to the common source line and thecontinuous isolation structures 240. After forming the bit lines, thesemiconductor device 500 is provided. - In the aforementioned embodiments of the present disclosure, as shown in
FIG. 19D , while thesemiconductor device 500 is used in a 3D memory device, the topmost layers of theconductive layers 220 on theopposite sidewalls isolation structure 240 may respectively function as a ground select line (GSL) and a string select line (SSL), and thesemiconductor device 500 is such as a vertical channel type memory device. - In the following description, another embodiment of the present disclosure of a
semiconductor structure 100 a is provided.FIGS. 20A-20B are the embodiment of the present disclosure of thesemiconductor structure 100 a. - Reference is made to
FIGS. 20A and 20B , in whichFIG. 20A is a top view of step S200 of forming thesemiconductor structure 100 a, andFIG. 20B is a cross-sectional view taken alongline 20B-20B inFIG. 20A . Compared to thesemiconductor structure 100 shown inFIGS. 14A-14E , thesemiconductor structure 100 a includes thememory structure cluster 300 without a U-shaped vertical cross section. In the embodiment, thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thefirst memory structure 310 are respectively separated from thememory structure layer 140, thechannel layer 150, and thedielectric structure 160 corresponding to thesecond memory structure 320 by theisolation structure 240, and theisolation structure 240 and each of the channel layers 150 are in contact with thesubstrate 110. For example, each of the channel layers 150 is electrically connected to the circuits configured on thesubstrate 110. - In order to provide the
semiconductor structure 100 a shown inFIGS. 20A-20B , a manufacturing method is further provided. The manufacturing method herein is substantially the same as the manufacturing method mentioned above. Some differences occur at forming therecess 400 shown inFIGS. 1A-1B and thetrench 170 shown inFIGS. 7A-7C . In detail, a difference of the manufacturing method herein further includes a step of extending therecess 400 through thememory structure layer 140 after forming thememory structure layer 140 in therecess 400, such that a portion of thesubstrate 110 is exposed from a bottom of therecess 400. Next, thechannel layer 150 is formed on thememory structure layer 140 and the portion of thesubstrate 110. The subsequent steps are referred to the manufacturing method mentioned in the aforementioned embodiments. Another difference occurs when coming to the step of forming thetrench 170 through the insulatinglayers 120, thedielectric layers 130, and thememory structure cluster 300. Thetrench 170 herein is formed by removing portions of the insulatinglayers 120, portions of thedielectric layers 130, a portion of thechannel layer 150, a portion of theconductive plug layer 152, and a portion of thedielectric structure 160 such that thememory structure layer 140, thechannel layer 150, theconductive plug layer 152, and thedielectric structure 160 corresponding to thefirst memory structure 310 are respectively separated from thememory structure layer 140, thechannel layer 150, theconductive plug layer 152, and thedielectric structure 160 corresponding to thesecond memory structure 320, by thetrench 170 and the subsequently disposedisolation structure 240. Each of the channel layers 150 is in contact with thesubstrate 110, such that the circuits on the substrate can be electrically connected to the channel layers 150. - It is to be noted that the connection relationships, the materials, and the advantages of the elements described above will not be repeated in the following description. In the following description, further details of providing a
semiconductor device 500 a by processing the manufacturedsemiconductor structure 100 a will be discussed. - Reference is made to
FIGS. 21A-21C , in whichFIG. 21A is a top view of step S210 of providing asemiconductor device 500 a,FIG. 21B is a cross-sectional view taken alongline 21B-21B inFIG. 21A , andFIG. 21C is a cross-sectional view taken alongline 21C-21C inFIG. 21A . Compared to thesemiconductor device 500 shown inFIGS. 19A-19D , there is no common source line formed on the twosecond contact structures semiconductor structure 100 a, instead, twothird contact structures second contact structures first contact structure 420, thesecond contact structure 440, and thethird contact structure 460 corresponding to thefirst memory structure 310 are respectively staggered with thefirst contact structure 430, thesecond contact structure 450, and thethird contact structure 470 corresponding to thesecond memory structure 320. Bit lines are formed onsemiconductor device 500 a to form a first group of bit lines (BL1) and a second group of bit lines (BL2). The first group of bit lines is electrically connected to thethird contact structures 460 disposed on thefirst memory structures 310 while the second group of bit lines is electrically connected to thethird contact structures 470 disposed on thesecond memory structures 320. - In the aforementioned embodiments of the present disclosure, while the
semiconductor device 500 a is used in a 3D memory device, thesubstrate 110 may function as a bottom source, the bottommost layer of theconductive layers 220 is such as a ground select line (GSL), the topmost layer of theconductive layers 220 is such as a string select line (SSL), and thesemiconductor device 500 a is such as a vertical channel type memory device. Furthermore, since the bilaterally symmetrically arrangedfirst memory structure 310 andsecond memory structure 320 are respectively connected to different bit lines (BL1 and BL2, also signal lines), the memory density is increased, and different program/erase operations can be processed simultaneously since different vertical memory structures can be selected via different bit lines simultaneously, and thus the processing speed can be further increased. - Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
- It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure covers modifications and variations of this disclosure provided they fall within the scope of the following claims.
Claims (8)
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US20190081060A1 (en) * | 2017-03-06 | 2019-03-14 | Yangtze Memory Technologies Co., Ltd. | Joint openning structures of three-dimensional memory devices and methods for forming the same |
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