TWI741630B - Semiconductor memory device - Google Patents

Abstract

The embodiment provides a small and high-performance semiconductor memory device. The semiconductor memory device of the embodiment has a plurality of memory cell array layers. The memory cell array layer has a first surface and a second surface opposite to the first surface and does not include a substrate, and includes: a plurality of memory cells, They are arranged in the memory cell array area in three dimensions; and the surface wiring layer is embedded in the first surface or/and the second surface; and the surface wiring layer of each of the memory cell array layers is perpendicular to the first When viewed in the direction of the surface, they are arranged to overlap, and the surface wiring layers are joined to each other, thereby stacking a plurality of the memory cell array layers.

Description

Semiconductor memory device

The embodiment of the present invention relates to a semiconductor memory device.

The present invention proposes a semiconductor memory device with a three-dimensional structure. A laminate body in which a plurality of electrode layers are laminated on a substrate and an insulating edge is formed to form a memory hole, and a charge storage film is interposed in the memory hole There is a silicon body that becomes a channel. In addition, a technique is proposed in which the control circuit of the memory cell array with the 3-dimensional structure is arranged directly below or directly above the memory cell array.

However, in this example, the memory density per unit area cannot be sufficiently increased.

The embodiment provides a small and high-performance semiconductor memory device.

According to an embodiment, a semiconductor memory device is provided, which has a plurality of memory cell array layers, the memory cell array layer has a first surface and a second surface opposite to the first surface and does not include a substrate, and includes: A plurality of memory cells, which are arranged in the memory cell array area in three dimensions; and a surface wiring layer, which is embedded in the first surface or/and the second surface; and the surface wiring layer of each of the memory cell array layers is self-contained When viewed in a direction perpendicular to the first surface, they are arranged so as to overlap, and the surface wiring layers are joined to each other, thereby stacking a plurality of the memory cell array layers.

1: Circuit board

2: substrate

10a: The first memory cell array

10b: 2nd memory cell array

11: Insulation layer

12a: Layer 1

13a: The first columnar part

13b: The second columnar part

14: Interlayer insulating film

15: Interlayer insulating film

16a: 1st bit line

16b: 2nd bit line

17a: 1st source line

18: Interlayer insulating film

19a: The first source-side wiring layer

19b: 2nd source side wiring layer

20: Channel body

21: Memory film

22: Block insulation film

23: charge accumulation film

24: Tunnel insulation film

25: Core insulation film

26: Insulating film

27: Insulating film

28a: The first memory cell array area

28b: The second memory cell array area

29: Step structure

30: contact plug

31: Interlayer insulation layer

32: contact plug

33: Character wiring layer

34: Select the gate wiring layer

35: Character line lead-out part

36: Select the gate lead

37a: Leading electrode of the first signal line

37b: Leading electrode of the second signal line

38a: The first surface wiring layer

38b: 3rd surface wiring layer

39a: Second surface wiring layer

39b: 4th surface wiring layer

40a: The first external connection electrode

40b: The second external connection electrode

41: Connection electrode on the circuit side

42: Circuit side wiring layer

50: The first insulating layer

51: 2nd insulating layer

52: External connection pad

61: Wiring layer

71: Wiring layer

100: Peripheral circuit layer

200: The first memory cell array layer

221: Silicon Nitride Film

222: Silicon oxide film

300: 2nd memory cell array layer

400: 3rd memory cell array layer

A: Part

BL: bit line

MC: memory cell

MS: memory string

MS1: memory string

MS2: memory string

MS3: memory string

Sa1: side 1

Sa2: Side 2

Sb1: Side 3

Sb2: Side 4

SG: select gate

SGD: Select the gate on the drain side

SGS: Source side select gate

SL: source line

STD: Select the transistor on the drain side

STS: Source-side select transistor

WL: Electrode layer

X: direction

Y: direction

Z: direction

FIG. 1 is a schematic cross-sectional view showing the semiconductor memory device of the first embodiment.

FIG. 2 is a schematic perspective view showing the semiconductor memory device of the first embodiment.

FIG. 3 is a schematic cross-sectional view showing the semiconductor memory device of the first embodiment.

4 is an enlarged schematic cross-sectional view of a part of the semiconductor memory device of the first embodiment.

FIG. 5 is a schematic perspective view showing the semiconductor memory device of the first embodiment.

6 is a schematic cross-sectional view showing the manufacturing method of the semiconductor memory device of the first embodiment.

FIG. 7 is a schematic cross-sectional view showing the manufacturing method of the semiconductor memory device of the first embodiment.

FIG. 8 is a schematic cross-sectional view showing the manufacturing method of the semiconductor memory device of the first embodiment.

FIG. 9 is a schematic cross-sectional view showing the manufacturing method of the semiconductor memory device of the first embodiment.

Fig. 10 is a schematic cross-sectional view of a semiconductor memory device of a first modification of the first embodiment.

11 is a schematic cross-sectional view of a semiconductor memory device according to a second modification of the first embodiment.

FIG. 12 is a schematic cross-sectional view showing the semiconductor memory device of the second embodiment.

FIG. 13 is a circuit diagram of the semiconductor memory device of the second embodiment.

FIG. 14 is a block diagram showing the system configuration of the semiconductor memory device of the second embodiment.

Hereinafter, the embodiment will be described with reference to the drawings. In addition, the same elements in the drawings are labeled with the same symbols.

(First Embodiment)

FIG. 1 is a schematic cross-sectional view of the semiconductor memory device of the first embodiment. The semiconductor memory device of the first embodiment has the following structure: a peripheral circuit layer 100 including a control circuit for controlling data writing, erasing, and reading to the memory cell, and a first memory cell including a plurality of first memory cells arranged in three dimensions. 1 The memory cell array layer 200 joins the build-up layers in an opposing manner, and adheres to each other. In addition, it has the following structure: the first memory cell array layer 200 and the second memory cell array layer 300 including a plurality of second memory cells arranged in a three-dimensional arrangement are joined and laminated in an opposing manner, and are bonded together.

First, the first memory cell array layer 200 will be described. The first memory cell array layer 200 has a first surface (lower surface) Sa1 in FIG. 1 and a second surface (upper surface) Sa2 opposite to the first surface, and has a first memory cell array 10a with a three-dimensional structure. 2 is a schematic perspective view of the semiconductor memory device of the first embodiment, and is a schematic perspective view of the first memory cell array 10a. In addition, in FIG. 2, the illustration of a part of the insulating layer such as the inter-electrode insulating layer is omitted. In addition, FIG. 2 is the upside down of FIG. 1, the upper side of FIG. 2 is the first surface side, and the lower side is the second surface side.

In FIG. 2, the two directions orthogonal to each other are referred to as the X direction and the Y direction, and the direction orthogonal to the X direction and Y direction (XY plane) and the multiple layers of electrode layers WL are stacked is referred to as Z Direction (stacking direction).

The first memory cell array 10a has a first laminated body 12a in which a plurality of electrode layers WL and insulating layers 11 are alternately laminated one by one. In the first layered body 12a, a plurality of first columnar portions 13a extending in the Z direction are provided. The first columnar portion 13a is provided in a cylindrical shape or an elliptical cylindrical shape, for example. The plurality of first columnar portions 13a are arranged in a zigzag grid or a square grid on the XY plane, for example. The electrode layer WL is separated into a plurality of blocks in the Y direction and extends in the X direction.

The electrode layer WL is, for example, a layer containing silicon as a main component. Furthermore, the electrode layer WL Contains boron as an impurity for making the silicon layer conductive. In addition, the electrode layer WL may also include metal silicide.

The insulating layer 11 mainly includes silicon and oxygen, for example, a silicon oxide film (SiO), a silicon oxynitride film (SiON), a silicon oxide film containing carbon (SiOC), and the like.

The drain side selection gate SGD is provided on the side of the first surface Sa1 of the first columnar portion 13a, which is the upper part, and the source side selection gate SGS is provided on the side of the second surface Sa2, which is the lower part. The drain-side selection gate SGD is disposed on the uppermost electrode layer WL via the insulating edge layer 11. The source-side selection gate SGS is disposed under the lowermost electrode layer WL via the insulating edge layer 11. Here, for example, the drain side selection gate SGD and the source side selection gate SGS may be formed thicker than the one-layer electrode layer WL.

The first bit line 16a is connected to the first surface Sa1 side, that is, the upper end of the first columnar portion 13a. A plurality of the first bit lines 16a are provided, and metal is used. The plurality of first bit lines 16a are spaced apart in the X direction and extend in the Y direction. The first bit line 16a is disposed on the drain side selection gate SGD with the insulating edge layer 11 and the interlayer insulating layer 14 interposed.

The first source line 17a is connected to the second surface Sa2 side, that is, the lower end of the first columnar portion 13a. The first source line 17a is disposed under the source-side selection gate SGS via the interlayer insulating layer 15. In addition, at the lower end of the first columnar portion 13a and further down the first source line 17a, a first source-side wiring layer 19a is provided in the interlayer insulating layer 18. The interlayer insulating layer 18 may also be a laminated layer.

3 is a schematic cross-sectional view of the semiconductor memory device of the first embodiment, and is a schematic cross-sectional view of the vicinity of the first columnar portion. Fig. 4 is a schematic cross-sectional view showing an enlarged part of part A in the vicinity of the first columnar part in Fig. 3. Figures 3 and 4 show cross-sections parallel to the YZ plane of Figure 2.

As shown in FIG. 3, the first columnar portion 13a is formed in an I-shaped memory hole formed in the first laminate 12a including a plurality of electrode layers WL and a plurality of insulating layers 11. For that Inside the memory hole, there is a channel main body 20 as a semiconductor channel. The channel main body 20 is, for example, a silicon film. The impurity concentration of the channel body 20 is lower than the impurity concentration of the electrode layer WL.

As shown in FIG. 4, the memory cell MC is provided with a memory film 21 between the inner wall of the memory hole and the channel main body 20. The memory film 21 has, for example, a block insulating film 22, a charge storage film 23, and a tunnel insulating film 24. Between the electrode layer WL and the channel main body 20, a block insulating film 22, a charge storage film 23, and a tunnel insulating film 24 are sequentially provided from the electrode layer WL side.

The channel main body 20 is provided in a cylindrical shape extending in the stacking direction of the laminate, and the memory film 21 is extended in the stacking direction of the laminate to surround the outer peripheral surface of the channel main body 20 and arranged in a cylindrical shape. The electrode layer WL surrounds the channel main body 20 through the memory film 21. In addition, a core insulating film 25 is provided on the inner side of the channel main body 20. The core insulating film 25 is, for example, a silicon oxide film.

The block insulating film 22 is in contact with the electrode layer WL, the tunnel insulating film 24 is in contact with the channel main body 20, and a charge storage film 23 is provided between the block insulating film 22 and the tunnel insulating film 24.

The channel main body 20 functions as a channel of the memory cell MC, and the electrode layer WL functions as a control gate of the memory cell. The charge accumulation film 23 functions as a data memory layer that accumulates the charges injected from the channel main body 20. That is, at the intersection of the channel main body 20 and each electrode layer WL, a memory cell MC with a structure in which the control gate surrounds the channel is formed.

The semiconductor memory device of the first embodiment is a non-volatile semiconductor memory device capable of erasing and writing data electrically and freely, and keeping the memory content even when the power is turned off.

The memory cell MC is, for example, a charge trap type memory cell. The charge storage film 23 has a plurality of trap sites for trapping charges, such as a silicon nitride film. It can also be a floating gate type memory cell.

The tunnel insulating film 24 injects charges into the charge storage film 23 from the channel main body 20 At this time, or when the charge accumulated in the charge storage film 23 diffuses to the channel main body 20, it becomes a potential energy barrier. The tunnel insulating film 24 is, for example, a silicon oxide film.

Alternatively, as the tunnel insulating film, a build-up film (ONO film) having a structure in which a silicon nitride film is sandwiched between a pair of silicon oxide films can also be used. If the ONO film is used as the tunnel insulating film, compared with a single layer of silicon oxide film, the erasing operation can be performed with a lower electric field.

The block insulating film 22 prevents the charge accumulated in the charge storage film 23 from diffusing to the electrode layer WL. The block insulating film 22 has, for example, a silicon nitride film 221 provided in contact with the electrode layer WL, and a silicon oxide film 222 provided between the silicon nitride film 221 and the charge storage film 23.

By disposing the silicon nitride film 221, which has a higher dielectric constant than the silicon oxide film 222, in contact with the electrode layer WL, the injection of tunnel electrons from the electrode layer WL during erasing can be suppressed. That is, by using a laminated film of a silicon oxide film and a silicon nitride film as the block insulating film 35, the charge blocking property can be improved.

As shown in FIGS. 2 and 3, the drain side selection transistor STD is provided on the upper part of the first columnar portion 13a, and the source side selection transistor STS is provided on the other lower part.

The memory cell MC, the drain-side select transistor STD, and the source-side select transistor STS are vertical transistors that flow current in the stacking direction (Z direction) of the laminate.

The drain-side selective gate SGD functions as a gate electrode (control gate) of the drain-side selective transistor STD. Between the drain side selection gate SGD and the channel main body 20, there is provided an insulating film 26 that functions as a gate insulating film of the drain side selection transistor STD (FIG. 3). The channel main body 20 of the drain side selection transistor STD provided in the first column portion 13a is above the drain side selection gate SGD, and is connected to the bit line BL.

The source-side selective gate SGS functions as the gate electrode (control gate) of the source-side selective transistor STS. Between the source side selection gate SGS and the channel body 20, there is The insulating film 27 functions as the gate insulating film of the source-side selective transistor STS (FIG. 3). The channel body 20 of the source-side selection transistor STS provided in the first column portion 13a is below the source-side selection gate SGS and is connected to the source line SL.

Further below the source line SL, a first source-side wiring layer 19 a is provided in the interlayer insulating layer 18.

The plurality of memory cells MC, drain-side selection transistors STD, and source-side selection transistors STS are connected in series through the channel main body 20 to form one memory string MS in the shape of an I. By arranging a plurality of memory strings MS in the X direction and the Y direction, the plurality of memory cells MC are arranged in three dimensions in the X direction, the Y direction and the Z direction.

FIG. 1 shows the region at the end of the first memory cell array 10a in the X direction. At the end of the first memory cell array region 28a where a plurality of memory cells MC are arranged, a step structure 29 of the electrode layer WL extending in the X direction is formed. In the step structure part 29, the X direction end part of the electrode layer WL of each layer is formed in a step shape. In the step structure portion 29, a plurality of contact plugs 30 connected to the electrode layers WL of each layer formed in a step shape are provided. The contact plug 30 penetrates the interlayer insulating layer 31 and is connected to the stepped electrode layer WL of each layer.

In addition, in the stepped structure portion 29, the select gate SG (drain-side select gate SGD, source-side select gate SGS) is connected to the contact plug 32.

The contact plug 30 connected to the electrode layer WL is connected to the character wiring layer 33. The contact plug 32 connected to the selection gate SG is connected to the selection gate wiring layer 34. The character wiring layer 33 and the selection gate wiring layer 34 are provided in the same layer.

The first memory cell array layer 200 does not include a substrate. In addition, on the second surface side of the first source line SL, a first source-side wiring layer 19a is further provided.

At least a part of the character wiring layer 33 and the selective gate wiring layer 34 The other wiring layers or plugs serve as the character line lead-out portion 35 and the select gate line lead-out portion 36, and are drawn to the outside of the first memory cell array region 28a when viewed from a direction perpendicular to the first surface. The character line lead-out portion 35 and the select gate line lead-out portion 36 drawn to the outside of the first memory cell array region 28a are connected to the first signal line lead electrode 37a provided on the outside of the first memory cell array region 28a.

In addition, the channel main body 20 of the first columnar portion 13a is electrically connected to the first bit line BL and the first source line SL. Furthermore, at least a part of the first bit line BL and the first source line SL is similarly used as the first bit line lead-out portion and the first source line lead-out portion by other wiring layers or plugs, and It is drawn out to the outside of the first memory cell array region 28a when viewed from a direction perpendicular to the first surface (not shown). The first bit line lead-out part and the first source line lead-out part drawn to the outside of the first memory cell array region 28a are connected to the first signal line lead electrode 37a provided on the outside of the first memory cell array region 28a.

The first surface Sa1 and the second surface Sa2 of the first memory cell array layer 200 are provided with a first surface wiring layer 38a and a second surface wiring layer 39a. The first surface wiring layer 38a and the second surface wiring layer 39a are embedded in the first surface Sa1 and the second surface Sa2, respectively, and the surfaces are exposed from an interlayer insulating layer (not shown). Here, for example, the first signal line extraction electrode 37a is electrically connected to the first surface wiring layer 38a and the second surface wiring layer 39a provided on the first surface Sa1 and the second surface Sa2 of the first memory cell array layer 200, respectively. The first signal line extraction electrode 37 a, the first surface wiring layer 38 a, and the second surface wiring layer 39 a penetrate the first memory cell array layer 200.

In addition, a first external connection electrode 40a is provided on the outer side of the first memory cell array region 28a. That is, the first external connection electrode 40a is provided in an area outside the stepped structure portion of the memory cell array. The first external connection electrode 40a is electrically connected to the first surface wiring layer 38a and the second surface wiring layer 39a respectively provided on the first surface Sa1 and the second surface Sa2 of the first memory cell array layer 200 catch. The first surface wiring layer 38a and the second surface wiring layer 39a are embedded in the first surface Sa1 and the second surface Sa2, respectively, and the surfaces are exposed from an interlayer insulating layer (not shown). The first external connection electrode 40 a, the first surface wiring layer 38 a, and the second surface wiring layer 39 a penetrate the first memory cell array layer 200.

The peripheral circuit layer 100 includes the circuit board 1. The circuit substrate 1 of the peripheral circuit layer 100 is, for example, a silicon substrate. A control circuit is formed on the circuit forming surface of the circuit board 1 of the peripheral circuit layer. As a control circuit, it is formed as an integrated circuit including a transistor. As a transistor, it has a MOSFET (Metal Oxide Semiconductor Field Effect Transistor: Metal Oxide Semiconductor Field Effect Transistor) structure including a gate electrode, source/drain regions, and the like. The source/drain regions of the MOSFET are connected to the circuit-side connection electrode 41 through other wiring layers or plugs. The circuit-side connection electrode 41 is electrically connected to the circuit-side wiring layer 42 provided on the circuit formation surface of the peripheral circuit layer 100. The circuit-side wiring layer 42 is embedded in the circuit formation surface, and the surface is exposed from the interlayer insulating layer (not shown).

The second memory cell array layer 300 has the same structure as the first memory cell array layer 200 shown in FIGS. 1 to 4. That is, the second memory cell array layer 300 has a third surface (lower surface) Sb1 in FIG. 1 and a fourth surface (upper surface) Sb2 opposite to the third surface, and has a second memory cell array 10b with a three-dimensional structure. . In addition, the description of the same configuration is omitted.

The second memory cell array layer 300 does not include a substrate. In addition, a second source-side wiring layer 19b is further provided on the fourth surface side from the second source line SL.

Similar to the first memory cell array layer 200, at least a part of the character wiring layer 33 and the selective gate wiring layer 34 is formed by other wiring layers or plugs as the word line lead-out portion 35 and the select gate line lead-out portion 36, and is led out to the outside of the second memory cell array area 28b when viewed from a direction perpendicular to the third surface. The character line lead-out portion 35 and the select gate line lead-out portion 36 drawn to the outside of the second memory cell array area 28b are arranged outside the second memory cell array area 28b The second signal line lead electrode 37b on the side is connected.

In addition, the channel main body 20 of the second columnar portion 13b is electrically connected to the second bit line BL and the second source line SL. Furthermore, at least a part of the second bit line BL and the second source line SL is led to the second bit line lead-out portion and the second source line lead-out portion through other wiring layers or plugs. The outer side of the second memory cell array region 28b when viewed from a direction perpendicular to the third surface. The second bit line lead-out portion and the second source line lead-out portion drawn to the outside of the first memory cell array region 28b are connected to the second signal line lead electrode 37b provided on the outer side of the second memory cell array region 28b. In addition, since the structure in the second memory cell array region 28b is the same as that of the first memory cell array layer 200, the description of the symbols is omitted.

The third surface Sb1 and the fourth surface Sb2 of the second memory cell array layer 300 are provided with a third surface wiring layer 38b and a fourth surface wiring layer 39b. The third surface wiring layer 38b and the fourth surface wiring layer 39b are embedded in the third surface Sb1 and the fourth surface Sb2, respectively, and the surfaces are exposed from the interlayer insulating layer (not shown). Here, for example, the second signal line extraction electrode 37b is electrically connected to the third surface wiring layer 38b and the fourth surface wiring layer 39b provided on the third surface and the fourth surface of the second memory cell array layer 300, respectively. The second signal line extraction electrode and the third and fourth surface wiring layers penetrate the second memory cell array layer 300.

In addition, a second external connection electrode 40b is provided on the outer side of the second memory cell array region 28b. That is, the second external connection electrode 40b is provided in a region of the memory cell array that is more outside than the stepped structure portion. The second external connection electrode 40b is electrically connected to the third surface wiring layer 38b and the fourth surface wiring layer 39b provided on the third surface Sb1 and the fourth surface Sb2 of the second memory cell array layer 300, respectively. The third surface wiring layer 38b and the fourth surface wiring layer 39b are embedded in the third surface Sb1 and the fourth surface Sb2, respectively, and the surfaces are exposed from the interlayer insulating layer (not shown). The second external connection electrode 40 b, the third surface wiring layer 38 b, and the fourth surface wiring layer 39 b penetrate the second memory cell array layer 300. In the fourth surface wiring layer 39b, the surface wiring layer electrically connected to the second external connection electrode 40b is provided 外连接垫52。 External connection pad 52.

As shown in FIG. 1, the first surface wiring layer 38a provided on the first surface Sa1 and the circuit side wiring layer 42 provided on the circuit forming surface are pasted and joined. The first surface wiring layer 38a and the circuit side wiring layer 42 are, for example, copper or a copper alloy containing copper as a main component. An insulating film (not shown) is provided around the first surface wiring layer 38a and the circuit side wiring layer 42. The insulating film is, for example, an inorganic film, a resin film, or the like. The first memory cell array layer 200 and the peripheral circuit layer 100 are electrically connected via the first surface wiring layer 38 a and the circuit side wiring layer 42.

In addition, as shown in FIG. 1, the second surface wiring layer 39a provided on the second surface Sa2 and the third surface wiring layer 38b provided on the third surface Sb1 are pasted and joined. The second surface wiring layer 39a and the third surface wiring layer 38b are, for example, copper or a copper alloy containing copper as a main component. An insulating film (not shown) is provided around the second surface wiring layer 39a provided on the second surface and the third surface wiring layer 38b provided on the third surface Sb1. The insulating film is, for example, an inorganic film including a silicon nitride film. The first memory cell array layer and the second memory cell array layer are electrically connected via the second surface wiring layer 39a and the third surface wiring layer 38b.

In addition, when the insulating film around the wiring layer is an inorganic film, bonding of the wiring layers can be performed on the bonding surface, and bonding by hydrogen bonding between the inorganic films can be performed. Therefore, if an inorganic film is used as the insulating film, since the gap between the joint surfaces is not easily generated, it is preferable in that underfilling using a resin mold is not required.

5 is a schematic perspective view of the semiconductor memory device of the first embodiment, and is a schematic perspective view of the electrical connection state of the peripheral circuit layer, the first memory cell array layer, and the second memory cell array layer.

As shown in FIG. 5, the peripheral circuit layer 100, the first memory cell array layer 200, and the second memory cell array layer 300 are led by the first signal line lead electrode, the second signal line lead electrode, and the first signal line lead electrode. The external connection electrode and the second external connection electrode (not shown) are electrically connected. Signal line lead-out electrodes are arranged outside the memory cell array regions 28a and 28b, and external connection electrodes are arranged on the outside of the memory cell array region, and the stepped structure part and the outer region of the memory cell array. When viewed from a direction perpendicular to the first surface Sa1, the signal line lead-out electrodes and external connection electrodes of the memory cell array layer are respectively arranged in the overlapping area. The signal lead-out electrode is electrically connected to the surface wiring layers 39a and 39b, and the external connection electrode of the second memory cell array layer 300, which becomes the uppermost layer, is electrically connected to the external connection pad 52. In addition, in FIG. 5, only a part of the electrical connection states of the first signal line extraction electrode, the second signal line extraction electrode, the first external connection electrode, and the second external connection electrode are shown, and the illustration is omitted otherwise.

Using FIGS. 6 to 9, the method of manufacturing the semiconductor memory device of the first embodiment will be described. 6 to 9 are related to the manufacturing method of the semiconductor memory device of the first embodiment, and are cross-sectional views of the semiconductor memory device.

As shown in FIG. 6, a control circuit including a transistor or the like is formed on the circuit board 1, and a peripheral circuit layer 100 having a circuit-side wiring layer 42 whose surface is exposed from an insulating film (not shown) is formed. In addition, a first insulating layer 50 is formed under the other substrate 2, such as a silicon oxide film as a buffer layer, and a first source line side wiring layer 19a and a first source line 17a are formed under the first insulating layer 50. A first selection gate SG, a plurality of electrode layers WL, etc. are formed under one source line 17a. Next, the memory string MS, the stepped structure portion 29, and the like are formed. Furthermore, a first surface wiring layer 38a whose surface is exposed from the first external connection electrode 40a, the first signal line extraction electrode 37a, and the insulating film (not shown) is formed, and the first memory cell array layer 200 is formed. Next, the circuit-side wiring layer 42 of the peripheral circuit layer 100 and the first surface wiring layer 38a of the first memory cell array layer 200 are laminated so as to face each other.

Next, as shown in FIG. 7, the peripheral circuit layer 100 and the first memory cell array layer 200 are laminated. At this time, the circuit-side wiring layer 42 and the first surface wiring layer 38a are joined. As its joining partner Methods, such as joining by applying mechanical pressure, and diffusion joining. Alternatively, inert plasma treatment is performed on the bonding surface, and the bonding is performed by hydrogen bonding due to the formation of OH groups on the bonding surface. Alternatively, an organic adhesive or the like is used for bonding. Thereafter, the substrate 2 is removed by, for example, a chemical solution such as KOH. At this time, the insulating films around the respective wiring layers may be joined to each other.

It is believed that since the memory cell array layer does not have a substrate, it is easily deformed by the stress applied to the memory cell array layer, causing the laminated semiconductor memory device to bend. Therefore, the second insulating layer 51 is formed. The second insulating layer 51 is a layer having stress in a direction opposite to the bending generated after removing the substrate, and is formed as a stress adjusting film. As the second insulating layer 51, for example, a silicon nitride film is formed. Thereby, the stress generated in the semiconductor memory device can be relieved, and the bending of the semiconductor memory device can be suppressed.

Next, the first insulating layer 50 and the second insulating layer 51 are removed so that the upper surfaces of the first external connection electrode 40a and the first signal line extraction electrode 37a are exposed to form grooves. As shown in FIG. 8, the second surface wiring layer 39a as a bonding metal is formed in this groove, and the upper surface of the second surface wiring layer 39a is exposed.

Next, following FIG. 8, the peripheral circuit layer 100 shown in FIG. 6 is replaced by the first memory cell array layer 200, and the first memory cell array layer 200 shown in FIG. 6 is replaced by the second memory cell array layer. 300. Repeat the same steps as in Figs. 6-8. As shown in FIG. 9, in the fourth surface wiring layer 39b exposed on the upper surface, an external connection pad 52 is formed on the surface wiring layer electrically connected to the second external connection electrode 40b. In this way, a semiconductor memory device in which the peripheral circuit layer 100, the first memory cell array layer 200, and the second memory cell array layer 300 are laminated can be formed.

In the first embodiment, the second memory cell array layer 300 is laminated on the first memory cell array layer 200, but one or more other memory cell array layers may be further laminated on the second memory cell array layer 300. At this time, at least a part of one or more other memory cell array layers The layer may also include a substrate. In this case, the bending of the stacked semiconductor memory device can be reduced.

In addition, the peripheral circuit layer 100 may not be laminated, and only a laminated body of the memory cell array layer may be formed.

(The first modification example)

Fig. 10 is a schematic cross-sectional view of a semiconductor memory device of a first modification of the first embodiment. A wiring layer 61 connecting the memory string MS1 of the first memory cell array layer 200 and the memory string MS2 of the second memory cell array layer 300 is provided. The wiring layer 61 is disposed inside the memory cell array area, and is connected to the first source-side wiring layer 19a of the first memory cell array layer 200 and the second bit line 16b of the second memory cell array layer 300. The first memory cell array layer and the second memory cell array layer are not connected via signal line lead-out electrodes arranged on the outer side of the memory cell array area.

In the first modification example, the first memory cell array layer and the second memory cell array layer are connected with the wiring layer provided on the inner side of the memory cell array area in addition to the signal line lead-out electrodes provided on the outside of the memory cell array area. .

By forming in this way, the electrode area required for the connection of the memory cell array layer can be reduced, and the chip area can be reduced.

(Second modification example)

11 is a schematic cross-sectional view of a semiconductor memory device according to a second modification of the first embodiment. The description of external connection electrodes is omitted.

At least a part of the character wiring layer and the selective gate wiring layer of the first memory cell array layer 200 are led out as the word line lead-out portion 35 and the select gate line lead-out portion 36 through other wiring layers or plugs. Fold back to the first memory cell array area when viewed in the direction perpendicular to the first surface Sa1 Inside the domain 28a. The character line lead-out portion 35 and the select gate line lead-out portion 36 drawn to the inner side of the first memory cell array area 28a are connected to the first signal line lead-out electrode 37a provided on the inner side of the first memory cell array area 28a.

In addition, at least a part of the first bit line BL and the first source line SL are similarly drawn out as the first bit line lead-out portion and the first source line lead-out portion by other wiring layers or plugs. When viewed from the direction perpendicular to the first surface Sa1, it turns back to the inner side of the first memory cell array region 28a (not shown). The first bit line lead-out portion and the first source line lead-out portion drawn to the inner side of the first memory cell array area 28a are connected to the first signal line lead-out electrode 37a provided on the inner side of the first memory cell array area 28a.

In addition, the first source-side wiring layer 19a on the second surface Sa2 side is connected to the first signal line extraction electrode 37a provided inside the first memory cell array region 28a. Here, a part of the first signal line extraction electrode 37a may also be provided on the outer side of the first memory cell array region 28a.

On the first surface Sa1 and the second surface Sa2 of the first memory cell array layer 200, a first surface wiring layer 38a and a second surface wiring layer 39a are respectively provided inside the memory cell array area. The first surface wiring layer 38a and the second surface wiring layer 39a disposed inside the memory cell array area are electrically connected to the first signal line extraction electrode 37a.

In the second memory cell array layer 300, similar to the first memory cell array layer 200, at least a part of the character wiring layer and the selective gate wiring layer is formed by other wiring layers or plugs as the character line lead-out portion 35 and selection The gate line lead-out portion 36 is drawn out, and is folded back to the inside of the second memory cell array region 28b when viewed in a direction perpendicular to the third surface Sb1. The character line lead-out portion 35 and the select gate line lead-out portion 36 drawn to the inner side of the second memory cell array area 28b are connected to the second signal line lead-out electrode 37b provided on the inner side of the second memory cell array area 28b.

In addition, at least a part of the second bit line BL and the second source line SL is connected by the The other wiring layers or plugs are led out as the second bit line lead-out portion and the second source line lead-out portion, and are folded back to the inner side of the second memory cell array area 28b when viewed from the direction perpendicular to the third surface (not shown) Show). The second bit line lead-out portion and the second source line lead-out portion drawn to the inner side of the second memory cell array region 28b are connected to the second signal line lead electrode 37b provided on the inner side of the second memory cell array region 28b. Here, a part of the second signal line extraction electrode 37b may also be provided on the outer side of the second memory cell array region 28b.

On the third surface Sb1 of the second memory cell array layer 300, a third surface wiring layer 38b is provided inside the memory cell array area. The third surface wiring layer 38 disposed inside the memory cell array area is electrically connected to the second signal line lead electrode 37b. Here, on the fourth surface Sb2 of the second memory cell array layer 300, a fourth surface wiring layer (not shown) may also be provided inside the memory cell array area. In this case, the fourth surface wiring layer provided inside the memory cell array region is electrically connected to the second signal line extraction electrode 37b.

Therefore, the signal line lead-out electrode of each memory cell array layer is connected to the surface wiring layer arranged inside the memory cell array area, and the surface wiring layer of each memory cell array layer can be arranged separately when viewed from a direction perpendicular to the first surface In the overlapping area. Thereby, when a plurality of memory cell array layers are laminated, the chip area can be further reduced, the wiring length can be suppressed, and the operation delay can be suppressed.

According to the second modification, at least a part of the bit lines or word lines are folded back to the inner side of the memory cell array area. The signal line lead-out electrodes connected via the bit line lead-out part and the word line lead-out part are arranged inside the memory cell array area. In addition, the signal line lead-out electrodes of each memory cell array layer are connected to the surface wiring layer arranged inside the memory cell array area, and the surface wiring layer of each memory cell array layer can be arranged separately when viewed from a direction perpendicular to the first surface In the overlapping area. With this, when there are multiple memory cell array layers stacked, the chip area can be further reduced Product, and suppress the wiring length, can suppress the operation delay.

According to the first embodiment, the first memory cell array layer 200 and the second memory cell array layer 300 do not have a substrate (for example, a silicon substrate). Therefore, when the first memory cell array layer 200 and the second memory cell array layer 300 are laminated and electrically connected, the TSV (Through Silicon Via) can be connected without forming a TSV (Through Silicon Via). Thereby, there is no need to perform the etching step of the substrate that takes cost or processing time, or the formation of an insulating film to prevent the short circuit between the substrate and the through hole, which can reduce the cost and increase the processing throughput.

In addition, since the memory cell array layer and the peripheral circuit layer are formed by different wafer processes, the formation of the memory cell array layer requires high temperature heat treatment, which can also suppress the diffusion of impurities in the transistors of the peripheral circuit layer or the metal Adverse effects such as deterioration of the wiring layer.

In addition, the memory cell array layer is laminated so that the first surface faces the peripheral circuit layer. Lead the bit line or the word line to the first surface side of the memory cell array layer, and connect the bit line or the word line to the signal line lead electrode. Since the memory cell array layer is laminated with the first surface facing the peripheral circuit layer, the wiring distance of the electrode layer can be reduced, and the adverse effect on the operating speed can be suppressed.

Furthermore, according to the first embodiment, a plurality of memory cell array layers are laminated on the peripheral circuit layer. By this, when the laminated body of 1 memory cell array layer is 48 layers, for example, by stacking 2 memory cell array layers, the 48-layer process technology can be used to realize the 96-layer memory that is twice the 48-layer. Cell array. Therefore, the memory density can be easily increased.

Furthermore, at least a part of the bit lines or word lines are led out to the outside of the memory cell array area, and the signal line lead-out electrodes connected via the bit line lead-out portion and the word line lead-out portion, etc. are arranged in the memory cell array area Outside. In addition, on the outer side of the memory cell array area, and the area outside the stepped structure portion of the memory cell array, external connection electrodes are provided. Memory cell array When viewed from a direction perpendicular to the first surface, the signal line lead-out electrodes and external connection electrodes of the column layer are respectively arranged in the overlapping area. Thereby, when a plurality of memory cell array layers are laminated, the wiring length can be suppressed, and the operation delay can be suppressed.

Alternatively, at least a part of the bit lines or word lines are folded back to the inner side of the memory cell array area. The signal line lead-out electrodes connected via the bit line lead-out part and the word line lead-out part are arranged inside the memory cell array area. In addition, the signal line lead-out electrode of each memory cell array layer is connected to the surface wiring layer arranged inside the memory cell array area, and the surface wiring layer of each memory cell array layer is respectively arranged on the surface when viewed from a direction perpendicular to the first surface Overlapping area. Thereby, when a plurality of memory cell array layers are laminated, the chip area can be further reduced, the wiring length can be suppressed, and the operation delay can be suppressed.

In addition, the external connection electrode and the surface wiring layer connected to the external connection electrode penetrate at least the upper and lower layers sandwiched by the memory cell array layer or/and the peripheral circuit layer (here, the first memory cell array layer) set up. In addition, the signal line extraction electrode and the surface wiring layer connected to the signal line extraction electrode at least penetrate through the upper and lower layers sandwiched by the memory cell array layer or/and the peripheral circuit layer (here, the first memory cell array layer) The way to set. Therefore, when a plurality of memory cell array layers are stacked, the wiring length can be further suppressed, the operation delay can be further suppressed, and the reliability can be improved.

Furthermore, the external connection electrodes can be arranged such as not connected to the memory cell, and external signals can be input to the peripheral circuit layer from the external connection pad without passing through the memory cell. Thereby, adverse effects such as operation delay can be further suppressed. In addition, since the signal line leading electrode is electrically connected to each memory cell array layer even in a path that is not connected to the memory cell, the signal line of each layer is not connected via the memory cell. Thereby, adverse effects such as operation delay can be further suppressed.

In addition, the memory cell array layer does not have a substrate, and there is no need to form TSV and other silicon through-circuit currents. pole. Instead of providing a substrate, a source-side wiring layer is provided on the second surface side (fourth surface side) of the memory cell array layer. Thereby, the stacked memory cell array layers can be arbitrarily connected, and the wiring area can be increased without increasing the chip area.

Furthermore, the first source-side wiring layer can be used as the first source lead-out portion of the first source line SL. The second source-side wiring layer can be used as the second source line lead-out portion of the second source line SL. In this way, in the memory cell array with the I-shaped columnar portion, the source side wiring layer is provided on the second surface side (fourth surface side) of the source line, so that the source can be effectively suppressed. The wiring length from wire to signal wire lead electrode.

In addition, the signal line extraction electrode and the surface wiring layer of the second memory cell array layer can also be formed by penetrating the second memory cell array layer in the same way as the first memory cell array layer. In this case, the device structure of the first memory cell array layer and the second memory cell array layer can be shared, and the characteristics such as stress generated by the memory cell array layer can be uniform. In addition, it is better in that the manufacturing processes of the first memory cell array layer and the second memory cell array layer can be shared, and the memory cell array layer can be manufactured efficiently.

In addition, in the first memory cell array layer or the second memory cell array layer, the bit line or the word line is drawn to the first surface side or the third surface side, and the bit line or the word line is connected to the signal line Lead out the electrode. The first memory cell array layer is laminated so that the first side faces the peripheral circuit layer, and the second memory cell array layer is laminated so that the third side faces the first memory cell array layer. That is, the first memory cell array layer and the second memory cell array layer lead out the signal lines in the same direction, and the first memory cell array layer and the second memory cell array layer are laminated in such a way that the orientations of the first memory cell array layer and the second memory cell array layer are the same. In this way, since the bit line or the word line is drawn to the side where the peripheral circuit layer is provided (the lower side in FIG. 1) and stacked on the peripheral circuit layer, the wiring distance of the electrode layer can be reduced, and the pairing operation can be suppressed The adverse effect of speed.

Also, suppose that the orientations of the first memory cell array layer and the second memory cell array layer are not In the case of uniformly facing stacked layers, for a memory cell array layer, for example, it must be placed on a tape, etc. After removing the substrate from the tape, the surface after removing the substrate is opposed to the peripheral circuit or another memory cell array layer Way stacking. If the first memory cell array layer and the second memory cell array layer are laminated with the same orientation, there is no need to use a tape or the like. That is, it can be formed by laminating the memory cell array layer formed on the substrate directly on the peripheral circuit layer with the surface of the substrate as the top, and removing the substrate. Thereby, the memory cell array layer and the second memory cell array layer are laminated with the same orientation, which is also preferable in that they can be easily formed without using a tape or the like.

(Second Embodiment)

Next, the semiconductor memory device of the second embodiment will be described. In addition, the basic configuration is the same as that of the first embodiment, so the description of the items explained in the first embodiment is omitted.

FIG. 12 is a schematic cross-sectional view of the semiconductor memory device of the second embodiment. In FIG. 12, for the semiconductor memory device of FIG. 1, a memory cell array layer is further laminated, and a peripheral circuit layer 100, a first memory cell array layer 200, and a second memory cell array layer are sequentially arranged from the bottom. 300. The third memory cell array layer 400.

Here, as shown in FIG. 12, the laminated second memory cell array layer 300 is between the third surface wiring layer 38b provided on the third surface Sb1 and the fourth surface wiring layer 39b provided on the fourth surface Sb2 , There is a wiring layer 71 connected to the memory string MS3. That is, the second memory cell array layer 300 is connected to the upper and lower memory cell array layers via the wiring layer 71 via the memory string MS3.

FIG. 13 is a circuit diagram of the semiconductor memory device of the second embodiment. In FIG. 13, a part of the circuit of the memory string MS3 connected to the wiring layer 71 is shown. There are plural memory cells, some of which are not shown in the figure. A plurality of memory cells are provided with drain-side selection transistors STD and source-side selection transistors STS, and the memory has an ID provided in the array layer of each memory cell array layer. remember The circuit of the memory string MS3 functions as a part of the selection circuit for selecting the array layer of the array layer.

FIG. 14 is a block diagram showing the system configuration of the semiconductor memory device of the second embodiment. In FIG. 14, there is shown a system configuration of a semiconductor memory device including an array layer selection circuit provided in the memory string MS3 connected to the wiring layer 71.

At each memory cell array layer, input address lines and array layer selection signal lines as signal lines. In the memory cell array layer, the ID of the signal line and the memory array layer of the array layer is used to determine whether to select the memory cell array layer, and the address line is input to the memory cell array.

By forming in this way, instead of using each signal line to individually select the memory cell array, the transistor and the memory cell in the memory string MS3 can be used to select the memory cell array layer, even if it is a semiconductor with a plurality of stacked memory cell array layers. The memory device can also greatly reduce the number of wiring.

Moreover, in this case, for each of the memory area or the memory block of the second memory cell array layer, the wiring layer 71 can also be used to connect to the upper and lower memory cell array layers, respectively. By forming in this way, each transistor and each memory cell in each memory string MS can be used to select a memory area or a memory block, even if it is a semiconductor memory device with a plurality of stacked memory cell array layers. Significantly reduce the number of wiring.

In the above, while referring to the drawings, the embodiment has been described. However, the present invention is not limited to this.

In the present invention, an example including a circuit substrate is described, but a case where only a memory cell array layer is laminated is also included in the scope of the present invention.

Those skilled in the art have made various design changes regarding the structure of the memory cell array constituting the present invention, as long as they do not depart from the gist of the present invention, they are also included in the scope of the present invention Inside.

Furthermore, according to yet another aspect, a semiconductor memory device is provided, which is characterized by having a 3-dimensional memory cell array of other configurations.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments or their changes are included in the scope or spirit of the invention, and are included in the invention described in the scope of the patent application and its equivalent scope.

1: Circuit board

10a: The first memory cell array

10b: 2nd memory cell array

19a: The first source-side wiring layer

19b: 2nd source side wiring layer

28a: The first memory cell array area

28b: The second memory cell array area

29: Step structure

30: contact plug

31: Interlayer insulation layer

32: contact plug

33: Character wiring layer

34: Select the gate wiring layer

35: Character line lead-out part

36: Select the gate lead

37a: Leading electrode of the first signal line

37b: Leading electrode of the second signal line

38a: The first surface wiring layer

38b: 3rd surface wiring layer

39a: Second surface wiring layer

39b: 4th surface wiring layer

40a: The first external connection electrode

40b: The second external connection electrode

41: Connection electrode on the circuit side

42: Circuit side wiring layer

52: External connection pad

100: Peripheral circuit layer

200: The first memory cell array layer

300: 2nd memory cell array layer

BL: bit line

Sa1: side 1

Sa2: Side 2

Sb1: Side 3

Sb2: Side 4

SG: select gate

SL: source line

WL: Electrode layer

X: direction

Z: direction

Claims (8)

A semiconductor memory device comprising: a substrate; a transistor provided on the substrate; a peripheral circuit layer having a first bonding metal provided on a bonding surface facing the memory cell array layer; and a memory cell array layer, which Bonded to the peripheral circuit layer; and the memory cell array layer includes: a laminate in which a plurality of electrode layers and insulating layers are alternately laminated in a first direction; and a columnar portion in the laminate in the first direction Extending, forming a memory cell at the portion intersecting the electrode layer; a first wiring layer, which is provided between the bonding surface and the laminate; a plug, which connects one of the plurality of electrode layers and the The first wiring layer extends in the first direction; and the second bonding metal is provided on the first bonding metal and is electrically connected to the first wiring layer; and the second bonding metal is formed from the first When viewed in the direction, it overlaps with the above-mentioned laminate. The semiconductor memory device of claim 1, wherein the first bonding metal and the second bonding metal are directly bonded. The semiconductor memory device of claim 1, wherein the memory cell array layer is connected to The first surface of the bonding surface and the second surface on the opposite side of the first surface, excluding the substrate; and the semiconductor memory device further includes: a second wiring layer provided on the second surface and the build-up layer Between the bodies; the third bonding metal, which is provided on the second surface, overlaps with the laminate when viewed from the first direction, and is electrically connected to the second wiring layer; and the signal line lead electrode, which is connected to The first wiring layer and the second wiring layer are electrically connected and extend in the first direction. The semiconductor memory device of claim 3, wherein a bit line is electrically connected to the first surface side of the columnar portion, and a source line is electrically connected to the second surface side of the columnar portion. The source line is further provided with the second wiring layer on the second surface side. The semiconductor memory device of claim 3 or 4, which further has at least one layer of other memory cell array layers of the same type as the above-mentioned memory cell array layer laminated in a manner opposed to the above-mentioned memory cell array layer, and has two or more layers The plural memory cell array layers. The semiconductor memory device of claim 5, wherein at least one memory cell array layer of the plurality of memory cell array layers is provided with a memory string as a part of the array layer selection circuit, and the memory string has a circuit for selecting the memory cell array layer The memory cell of the ID of the crystal and memory array layer. The semiconductor memory device of claim 6, wherein the plurality of memory cell array layers are at least three layers of memory cell array layers, and a part of the array layer selection circuit is arranged in the plurality of memory cell array layers by other memory cells A memory cell array layer sandwiched by the array layer. The semiconductor memory device of claim 6, wherein a part of the array layer selection circuit is disposed in each memory area or memory block of the at least one memory cell array layer.

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