Semiconductor memory device
11756898 · 2023-09-12
Assignee
Inventors
- Hideki ITAI (Chigasaki, JP)
- Mitsuhiro NOGUCHI (Fujisawa, JP)
- Hiromasa YOSHIMORI (Yokohama, JP)
- Hideyuki TABATA (Yokohama, JP)
- Yasushi NAKAJIMA (Kawasaki, JP)
Cpc classification
H10B41/41
ELECTRICITY
H01L23/5226
ELECTRICITY
H10B43/27
ELECTRICITY
International classification
H10B41/00
ELECTRICITY
H01L23/522
ELECTRICITY
H10B41/27
ELECTRICITY
H10B41/41
ELECTRICITY
H10B43/27
ELECTRICITY
Abstract
A semiconductor memory device includes: two memory blocks; a first structure disposed between the two memory blocks; and a second structure separated from the two memory blocks, or a plurality of second structures. The two memory blocks include a plurality of first conductive layers and a plurality of first insulating layers alternately arranged. The first structure has one end, and the one end is closer to the substrate than the plurality of first conductive layers are. The second structure has one end, and the one end is closer to the substrate than at least apart of the first conductive layers among the plurality of first conductive layers is. Another end of the first structure and another end of the second structure are farther from the substrate than the plurality of first conductive layers are. The second structure is separated from the first structure.
Claims
1. A semiconductor memory device comprising: a substrate; two memory blocks arranged in a first direction, the two memory blocks extending in a second direction intersecting with the first direction; a first structure disposed between the two memory blocks, the first structure extending in the second direction; a second structure separated from the two memory blocks in the second direction, the second structure extending in the first direction; and a plurality of bit lines arranged in the second direction, the plurality of bit lines extending in the first direction and being connected to the two memory blocks, wherein the two memory blocks include a plurality of first conductive layers and a plurality of first insulating layers alternately arranged in a third direction intersecting with a surface of the substrate, the first structure has a first end parallel to the surface of the substrate and a second end parallel to the surface of the substrate, and the first end is closer to the substrate than the plurality of first conductive layers and the second end, the second structure has a third end parallel to the surface of the substrate and a fourth end parallel to the surface of the substrate, and the third end is closer to the substrate than at least a part of the first conductive layers among the plurality of first conductive layers and the fourth end, the second end of the first structure and the fourth end of the second structure are farther from the substrate than the plurality of first conductive layers and closer to the substrate than the plurality of bit lines, the third end and the fourth end of the second structure extend in the first direction, a length of each of the third end and the fourth end of the second structure in the first direction is greater than a width of at least one of the two memory blocks in the first direction, and the second structure is separated from the first structure in the second direction.
2. The semiconductor memory device according to claim 1, wherein the second structure has a width in the second direction smaller than a width in the first direction of the first structure.
3. The semiconductor memory device according to claim 2, wherein the third end of the second structure is farther from the substrate than one of the plurality of first conductive layers closest to the substrate.
4. The semiconductor memory device according to claim 1, wherein the second structure has a width in the second direction greater than a width in the first direction of the first structure.
5. The semiconductor memory device according to claim 1, wherein the second structure includes a second conductive layer extending in the first direction.
6. The semiconductor memory device according to claim 5, wherein the second conductive layer is electrically connected to an external terminal configured to supply a ground voltage.
7. The semiconductor memory device according to claim 1, wherein the substrate includes a first well region, the two memory blocks are disposed on or above the first well region, and the second structure is disposed at a position overlapping the first well region viewed in the third direction.
8. The semiconductor memory device according to claim 7, wherein the second structure includes a second conductive layer extending in the first direction, and the second conductive layer is connected to the first well region.
9. The semiconductor memory device according to claim 1, wherein the second structure includes a second conductive layer extending in the first direction, the semiconductor memory device includes: a second insulating layer disposed on the surface of the substrate; a first semiconductor layer disposed on a surface of the second insulating layer, and a third conductive layer disposed on a surface of the first semiconductor layer, and the second conductive layer is connected to the third conductive layer.
10. The semiconductor memory device according to claim 7, comprising a third structure separated from the two memory blocks in the second direction, the third structure extends in the first direction, wherein the third structure includes a fourth conductive layer extending in the first direction, the substrate includes a second well region, the first well region is disposed in the second well region, and the fourth conductive layer is connected to the second well region.
11. The semiconductor memory device according to claim 7, comprising a plurality of third structures separated from the two memory blocks in the second direction, the plurality of third structures being disposed in the first direction, wherein the third structure includes a fourth conductive layer extending in the first direction, the substrate includes a second well region, the first well region is disposed in the second well region, and the fourth conductive layer is connected to the second well region.
12. The semiconductor memory device according to claim 1, comprising a second semiconductor layer disposed between the substrate and the two memory blocks, wherein the second structure is disposed at a position overlapping the second semiconductor layer viewed in the third direction.
13. The semiconductor memory device according to claim 12, wherein the second structure includes a second conductive layer extending in the first direction, and the second conductive layer is connected to the second semiconductor layer.
14. The semiconductor memory device according to claim 1, comprising a third insulating layer that covers at least a part of a side surface in the second direction of the second structure.
15. The semiconductor memory device according to claim 1, further comprising: a third structure disposed in parallel with the second structure, the second structure provided between the two memory blocks and the third structure.
16. The semiconductor memory device according to claim 15, wherein the third structure has a fifth end extending in the first direction and a sixth end extending in the first direction, the fifth end and the sixth end are parallel to the surface of the substrate, a length of each of the fifth end and the sixth end in the first direction is greater than the width of the at least one of the two memory blocks in the first direction, wherein the fifth end is closer to the substrate than the sixth end, and wherein the sixth end is farther from the substrate than the plurality of first conductive layers and closer to the substrate than the plurality of bit lines.
17. A semiconductor memory device comprising: a substrate; two memory blocks arranged in a first direction, the two memory blocks extending in a second direction intersecting with the first direction; a first structure disposed between the two memory blocks, the first structure extending in the second direction; a second structure separated from the two memory blocks in the second direction, the second structure extending in the first direction; and a plurality of bit lines arranged in the second direction, the plurality of bit lines extending in the first direction and being connected to the two memory blocks, wherein the two memory blocks include a plurality of first conductive layers and a plurality of first insulating layers alternately arranged in a third direction intersecting with a surface of the substrate, the first structure has a first end parallel to the surface of the substrate and a second end parallel to the surface of the substrate, and the first end is closer to the substrate than the plurality of first conductive layers and the second end, the second structure has a third end parallel to the surface of the substrate and a fourth end parallel to the surface of the substrate, and the third end is closer to the substrate than at least a part of the first conductive layers among the plurality of first conductive layers and the fourth end, the second structure has a generally rectangular shape including a first side extending along the first direction and a second side extending along the third direction, the first side corresponding to the fourth end, a length of the first side being greater than a width of at least one of the two memory blocks along the first direction, a length of the second side being greater than a width of the at least one of the two memory blocks along the third direction, the second end of the first structure and the fourth end of the second structure are farther from the substrate than the plurality of first conductive layers and closer to the substrate than the plurality of bit lines, and the second structure is separated from the first structure in the second direction.
18. The semiconductor memory device according to claim 17, wherein the second structure has a width in the second direction smaller than a width in the first direction of the first structure.
19. The semiconductor memory device according to claim 17, wherein the second structure has a width in the second direction greater than a width in the first direction of the first structure.
20. The semiconductor memory device according to claim 17, wherein the second structure includes a second conductive layer extending in the first direction.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(32)
(33)
(34)
(35)
(36)
(37)
DETAILED DESCRIPTION
(38) A semiconductor memory device according to one embodiment includes a substrate; two memory blocks arranged in a first direction, the two memory blocks extending in a second direction intersecting with the first direction; a first structure disposed between the two memory blocks, the first structure extending in the second direction; a second structure separated from the two memory blocks in the second direction, the second structure extending in the first direction; and a plurality of bit lines arranged in the second direction, the plurality of bit lines extending in the first direction and being connected to the two memory blocks, wherein the two memory blocks include a plurality of first conductive layers and a plurality of first insulating layers alternately arranged in a third direction intersecting with a surface of the substrate, the first structure has one end in the third direction, and the one end is closer to the substrate than the plurality of first conductive layers are, the second structure has one end in the third direction, and the one end is closer to the substrate than at least a part of the first conductive layers among the plurality of first conductive layers is, another end in the third direction of the first structure and another end in the third direction of the second structure are farther from the substrate than the plurality of first conductive layers are and closer to the substrate than the plurality of bit lines are, and the second structure is separated from the first structure in the second direction.
(39) A semiconductor memory device according to one embodiment includes: a substrate; two memory blocks arranged in a first direction, the two memory blocks extending in a second direction intersecting with the first direction; a first structure disposed between the two memory blocks, the first structure extending in the second direction; a plurality of second structures separated from the two memory blocks in the second direction, the plurality of second structures being disposed in the first direction; and a plurality of bit lines arranged in the second direction, the plurality of bit lines extending in the first direction and being connected to the two memory blocks, wherein the two memory blocks include a plurality of first conductive layers and a plurality of first insulating layers alternately arranged in a third direction intersecting with a surface of the substrate, the first structure has one end in the third direction, and the one end is closer to the substrate than the plurality of first conductive layers are, the second structure has one end in the third direction, and the one end is closer to the substrate than at least a part of the first conductive layers among the plurality of first conductive layers is, another end in the third direction of the first structure and another end in the third direction of the second structure are farther from the substrate than the plurality of first conductive layers are and closer to the substrate than the plurality of bit lines are, and the second structure is separated from the first structure in the second direction.
(40) Next, the semiconductor memory device according to embodiments are described in detail with reference to the drawings. The following embodiments are only examples, and not described for the purpose of limiting the present invention. The following drawings are schematic, and for convenience of description, a part of a configuration and the like is sometimes omitted. Parts common in a plurality of embodiments are attached by same reference numerals and their descriptions may be omitted.
(41) In this specification, when referring to “semiconductor memory device,” it may mean a memory die and may mean a memory system including a control die, such as a memory chip, a memory card, and a Solid State Drive (SSD). Further, it may mean a configuration including a host computer, such as a smartphone, a tablet terminal, and a personal computer.
(42) In this specification, when referring to that a first configuration “is electrically connected” to a second configuration, the first configuration may be directly connected to the second configuration, and the first configuration may be connected to the second configuration via a wiring, a semiconductor member, a transistor, or the like. For example, when three transistors are connected in series, even when the second transistor is in OFF state, the first transistor is “electrically connected” to the third transistor.
(43) In this specification, a direction parallel to an upper surface of the substrate is referred to as an X-direction, a direction parallel to the upper surface of the substrate and perpendicular to the X-direction is referred to as a Y-direction, and a direction perpendicular to the upper surface of the substrate is referred to as a Z-direction.
(44) In this specification, a direction along a predetermined plane may be referred to as a first direction, a direction along this predetermined plane and intersecting with the first direction may be referred to as a second direction, and a direction intersecting with this predetermined plane may be referred to as a third direction. These first direction, second direction, and third direction may each correspond to any of the X-direction, the Y-direction, and the Z-direction and need not correspond to these directions.
(45) Expressions, such as “above” and “below,” in this specification are based on the substrate. For example, a direction away from the substrate along the Z-direction is referred to as above and a direction approaching the substrate along the Z-direction is referred to as below. A lower surface and a lower end of a certain configuration mean a surface and an end portion at the substrate side of this configuration. An upper surface and an upper end of a certain configuration mean a surface and an end portion at a side opposite to the substrate of this configuration. A surface intersecting with the X-direction or the Y-direction is referred to as a side surface and the like. A length in a predetermined direction may be referred to as a width or a thickness.
(46) In this specification, when referring to a “width,” a “length,” a “thickness,” or the like in a predetermined direction of a configuration, a member, or the like, this may mean a width, a length, a thickness, or the like in a cross-sectional surface or the like observed with a Scanning electron microscopy (SEM), a Transmission electron microscopy (TEM), or the like.
First Embodiment
(47) [Structure]
(48)
(49)
(50) Next, configurations included in the semiconductor memory device according to the embodiment will be described with reference to
(51) [Structure of Semiconductor Substrate 100]
(52) The semiconductor substrate 100 (
(53) [Structure of Memory Block BLK in Memory Hole Region R.sub.MH]
(54) the memory hole region R.sub.MH of the memory block BLK includes a plurality of conductive layers 110 arranged in the Z-direction, a plurality of semiconductor layers 120 extending in the Z-direction, and a plurality of gate insulating films 130 (
(55) The conductive layer 110 is an approximately plate-shaped conductive layer extending in the X-direction. The conductive layer 110 may include, for example, a stacked film of a barrier conductive film, such as titanium nitride (TiN), and a metal film, such as tungsten (W). The conductive layer 110 may contain, for example, polycrystalline silicon containing impurities, such as phosphorus (P) or boron (B). Between the plurality of conductive layers 110 arranged in the Z-direction, insulating layers 101, such as silicon oxide (SiO.sub.2), are disposed. A part of the plurality of conductive layers 110 function as gate electrodes of word lines and a plurality of memory cells connected thereto. A part of the plurality of conductive layers 110 function as gate electrodes of select gate lines and select gate transistors connected thereto.
(56) A conductive layer 111 is disposed below the conductive layers 110. The conductive layer 111 may include, for example, a stacked film of a barrier conductive film, such as titanium nitride (TiN), and a metal film, such as tungsten (W). Between the conductive layer 111 and the conductive layer 110, the insulating layer 101, such as silicon oxide (SiO.sub.2), is disposed. The conductive layer 111 functions as gate electrodes of select gate lines and select gate transistors connected thereto.
(57) For example, as illustrated in
(58) An impurity region 121 containing N-type impurities, such as phosphorus (P), is disposed in an upper end portion of the semiconductor layer 120. The impurity regions 121 are each connected to the plurality of bit lines BL arranged in the X-direction via a contact Ch and a contact Cb (see
(59) A lower end portion of the semiconductor layer 120 is connected to the P-type well region 100P.sub.1 of the semiconductor substrate 100 via a semiconductor layer 122 formed of single-crystal silicon (Si) or the like. The semiconductor layer 122 functions as a channel region of the select gate transistor. An outer peripheral surface of the semiconductor layer 122 is surrounded by the conductive layer 111, and opposed to the conductive layer 111. An insulating layer 123 of silicon oxide or the like is disposed between the semiconductor layer 122 and the conductive layer 111.
(60) The gate insulating film 130 has an approximately cylindrical shape that covers the outer peripheral surface of the semiconductor layer 120.
(61) For example, as illustrated in
(62)
(63) [Structure of Memory Block BLK in Hook-Up Region R.sub.HU]
(64) For example, as illustrated in
(65) For example, as illustrated in
(66) As illustrated in
(67) [Structure of Inter-Block Structure ST.sub.X1]
(68) The inter-block structure ST.sub.X1 includes, for example, as illustrated in
(69) [Structure of Row Decoder Region R.sub.RD and Peripheral Circuit Region R.sub.PC]
(70) The row decoder region R.sub.RD (
(71) For example, as illustrated in
(72) In the row decoder region R.sub.RD, the semiconductor substrate region 100S of the semiconductor substrate 100 functions as channel regions and the like of a plurality of transistors Tr constituting the peripheral circuit PC. In the peripheral circuit region R.sub.PC, the N-type well region 100N, the P-type well region 100P, and the semiconductor substrate region 100S of the semiconductor substrate 100 each function as channel regions and the like of the plurality of transistors Tr constituting the peripheral circuit PC.
(73) The gate insulating films 210 are disposed in the N-type well region 100N, the P-type well region 100P, and the semiconductor substrate region 100S of the semiconductor substrate 100. The gate insulating film 210 contains silicon oxide (SiO.sub.2) or the like.
(74) The gate electrode 220 includes, for example, semiconductor layers 221, 222 of polycrystalline silicon containing impurities, such as phosphorus (P) or boron (B), or the like and a conductive layer 223 of tungsten (W) or the like. An insulating layer 225 of silicon nitride (SiN) or the like is disposed on an upper surface of the gate electrode 220.
(75) The contact CS extends in the Z-direction and has a lower end connected to the semiconductor substrate 100 or the upper surface of the gate electrode 220. As illustrated in
(76) [Structure of Region between Memory Cell Array Region R.sub.MCA and Row Decoder Region R.sub.RD]
(77) As illustrated in
(78) The guard ring region R.sub.GR1 is disposed in the P-type well region 100P.sub.1 in common with the memory cell array region R.sub.MCA, and formed to surround the memory cell array region R.sub.MCA in the surface of the semiconductor substrate 100. The insulating region 100I.sub.1 is disposed between the guard ring region R.sub.GR1 and the guard ring region R.sub.GR2, and formed to surround the guard ring region R.sub.GR1 in the surface of the semiconductor substrate 100.
(79) The guard ring region R.sub.GR2 is disposed in the N-type well region 100N between the P-type well region 100P.sub.1 and the semiconductor substrate region 100S, and formed to surround the insulating region 100I.sub.1 in the surface of the semiconductor substrate 100. In the guard ring region R.sub.GR2, an impurity region 100n.sub.2 containing N-type impurities, such as phosphorus (P), is disposed in the surface of the semiconductor substrate 100. In the guard ring region R.sub.GR2, a plurality of contacts CS are disposed along this impurity region 100n.sub.2. The plurality of contacts CS supply a well voltage to the N-type well region 100N. The insulating region 100I.sub.2 is disposed between the guard ring region R.sub.GR2 and the guard ring region R.sub.GR3, and formed to surround the guard ring region R.sub.GR2 in the surface of the semiconductor substrate 100.
(80) The guard ring region R.sub.GR3 is disposed in a P-type well region 100P.sub.2 disposed separately from the P-type well region 100P.sub.1, and formed to surround the insulating region 100I.sub.2 in the surface of the semiconductor substrate 100. In the guard ring region R.sub.GR3, an impurity region 100p.sub.2 containing P-type impurities, such as boron (B), is disposed in the surface of the semiconductor substrate 100. In the guard ring region R.sub.GR3, a plurality of contacts CS are disposed along this impurity region 100p.sub.2. The plurality of contacts CS supply a well voltage to the P-type well region 100P.sub.2.
(81) Between the guard ring region R.sub.GR1 and the memory cell array region R.sub.MCA, a dummy transistor structure DTr and a block side structure ST.sub.Y1 are disposed. The dummy transistor structure DTr includes the gate insulating film 210, the gate electrode 220, and the insulating layer 225 included in the transistor Tr. However, these configurations do not function as the transistor Tr. The block side structure ST.sub.Y1 is disposed at the memory cell array region R.sub.MCA side with respect to the dummy transistor structure DTr.
(82) [Structure of Block Side Structure ST.sub.Y1]
(83) For example, as illustrated in
(84) [Manufacturing Method]
(85) Next, with reference to
(86) In the manufacture of the semiconductor memory device according to the embodiment, first, a plurality of transistors Tr (
(87) Next, for example, as illustrated in
(88) Next, for example, as illustrated in
(89) Next, an insulating layer 102 (see
(90) Next, for example, as illustrated in
(91) Next, for example, as illustrated in
(92) Next, for example, as illustrated in
(93) Next, for example, as illustrated in
(94) Next, for example, as illustrated in
(95) Next, for example, the inter-block structure ST.sub.X1 is formed in the trench STA.sub.X1 as illustrated in
(96) Subsequently, the contacts CC, CS, the wirings m0, m1, and the like are formed, thus forming the semiconductor memory device according to the first embodiment.
COMPARATIVE EXAMPLE
(97) Next, a semiconductor memory device according to the comparative example will be described with reference to
(98) Next, a method for manufacturing the semiconductor memory device according to the comparative example will be described with reference to
Effect of First Embodiment
(99) In the manufacture of the semiconductor memory device according to the comparative example, in the process described with reference to
(100) Here, in the manufacture of the semiconductor memory device according to the first embodiment, in the process described with reference to
(101) X-direction of the insulating layer 102 can be released to the row decoder region R.sub.RD side, thus allowing appropriately reducing the distortion of the hollow structure as described above.
(102) For example, when the trench STA.sub.X1 intersects with the trench STA.sub.Y1, a gas of RIE concentrates on a part at which the trench STA.sub.X1 intersects with the trench STA.sub.Y1 in the process described with reference to
(103) For example, when the trench STA.sub.X1 intersects with the trench STA.sub.Y1, the structure disposed on the semiconductor substrate 100 is completely separated in the Y-direction in the process described with reference to
(104) When the compressive stress in the X-direction of the insulating layer 102 is to be transferred to the row decoder region R.sub.RD side by the trench STA.sub.Y1 as described above, the trench STA.sub.Y1 is preferably disposed at the proximity of the memory cell array region R.sub.MCA. This is because as the distance between the trench STA.sub.Y1 and the memory cell array region R.sub.MCA decreases, the width in the X-direction of the insulating layer 102 decreases, and the insulating layer 102 is easily deformed in the X-direction. Therefore, as described with reference to
(105) As described with reference to
Second Embodiment
(106) Next, a semiconductor memory device according to the second embodiment will be described with reference to
(107) In this configuration, since the two conductive layers LI.sub.Y1 disposed at the proximity of the memory cell array region R.sub.MCA both function as the shield electrodes, the memory blocks BLK can be more appropriately protected from the external electromagnetic wave.
Third Embodiment
(108) Next, a semiconductor memory device according to the third embodiment will be described with reference to
(109) The block side structure ST.sub.Y3 is basically configured similarly to the block side structure ST.sub.Y1. However, the conductive layer LI.sub.Y1 included in the block side structure ST.sub.Y1 is connected to the P-type well region 100P.sub.1 via the P-type impurity region 100p.sub.Y1. Meanwhile, a conductive layer LI.sub.Y3 included in the block side structure ST.sub.Y3 is connected to the N-type well region 100N via the impurity region 100n.sub.2.
(110) In this configuration, the two conductive layers LI.sub.Y1 disposed at the proximity of the memory cell array region R.sub.MCA and the conductive layer LI.sub.Y3 all function as the shield electrodes, the memory blocks BLK can be more appropriately protected from the external electromagnetic wave.
Fourth Embodiment
(111) Next, a semiconductor memory device according to the fourth embodiment will be described with reference to
(112) The block side structure ST.sub.Y4 is basically configured similarly to the block side structure ST.sub.Y1. However, a dummy transistor structure DTr′ is disposed below the block side structure ST.sub.Y4. The dummy transistor structure DTr′ is configured similarly to the dummy transistor structure DTr. A lower end of a conductive layer LI.sub.Y4 included in the block side structure ST.sub.Y4 is connected to the upper surface of the conductive layer 223 included in this dummy transistor structure DTr′.
(113) Also in this configuration, since both the conductive layer LI.sub.Y1 and the conductive layer LI.sub.Y4 disposed at the proximity of the memory cell array region R.sub.MCA function as the shield electrodes, the memory blocks BLK can be more appropriately protected from the external electromagnetic wave.
Fifth Embodiment
(114) Next, with reference to
(115) The block side structure ST.sub.Y5 is basically configured similarly to the block side structure ST.sub.Y1. However, as described with reference to
(116) The semiconductor memory device according to the fifth embodiment is basically manufactured similarly to the semiconductor memory device according to the first embodiment. However, in the manufacturing method according to the fifth embodiment, in the processes described with reference to
(117) With this configuration, the distortion of the hollow structure as described above can be reduced with a smaller area.
(118)
Sixth Embodiment
(119) Next, a semiconductor memory device according to the sixth embodiment will be described with reference to
(120) However, the semiconductor memory device according to the sixth embodiment includes an inter-block structure ST.sub.X6 instead of the inter-block structure ST.sub.X1. The inter-block structure ST.sub.X6 is basically configured similarly to the inter-block structure ST.sub.X1. However, as described with reference to
(121) As illustrated in
(122) In the semiconductor memory device according to the sixth embodiment, the block side structure ST.sub.Y1 is disposed at the position overlapping the conductive layer 141 viewed in the Z-direction. The lower end of the block side structure ST.sub.Y1 is connected to the semiconductor layer 140.
Other Embodiments
(123) The semiconductor memory devices according to the first embodiment to the sixth embodiment have been exemplified above. However, the above-described configurations and the manufacturing methods are merely examples, and the specific configurations and the like are appropriately adjustable.
(124) For example, the lower end of the semiconductor layer 120 according to the first embodiment to the fifth embodiment is connected to the P-type well region 100P.sub.1 of the semiconductor substrate 100. However, this configuration is merely an example, and a specific configuration is appropriately adjustable. For example, the lower end of the semiconductor layer 120 may be connected to the N-type well region 100N. For example, as exemplified in the sixth embodiment, a semiconductor layer of, for example, polycrystalline silicon containing N-type impurities, such as phosphorus (P), or P-type impurities, such as boron (B), may be disposed above the semiconductor substrate 100, and the lower end of the semiconductor layer 120 may be connected to this semiconductor layer. In this case, the block side structures ST.sub.Y1, ST.sub.Y3, ST.sub.Y4, and ST.sub.Y5 may be disposed not at the position overlapping the P-type well region 100P.sub.1 viewed in the Z-direction but at the position overlapping this semiconductor layer viewed in the Z-direction. In addition, in this case, the lower ends of the inter-block structures ST.sub.X1, ST.sub.X6 and the lower ends of the block side structures ST.sub.Y1, ST.sub.Y3, ST.sub.Y4, and ST.sub.Y5 may be connected not to the surface of the semiconductor substrate 100 but to this semiconductor layer.
(125) The semiconductor memory devices according to the respective embodiments only need to each include at least one of the block side structures ST.sub.Y1, ST.sub.Y3, ST.sub.Y4, and ST.sub.Y5. For example, the semiconductor memory device according to the first embodiment may include the block side structure ST.sub.Y3 or the block side structure ST.sub.Y4 instead of the block side structure ST.sub.Y1. For example, the semiconductor memory device according to the sixth embodiment may include the block side structure ST.sub.Y5 in addition to the block side structure ST.sub.Y1 or instead of the block side structure ST.sub.Y1. In this case, the width in the X-direction of the block side structure ST.sub.Y5 may be approximately same as the width W.sub.STX6 in the Y-direction of the inter-block structure ST.sub.X6, or may be smaller than the width W.sub.STX6.
(126) In the example of
(127) In the above-described examples, the block side structures ST.sub.Y1, ST.sub.Y3, ST.sub.Y4, and ST.sub.Y5 have approximately plate shapes extending in the Z-direction and the Y-direction. However, for example, these block side structures may be formed in approximately columnar shapes as illustrated in, for example,
(128) [Others]
(129) While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms: furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.