This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2021-042761, filed on Mar. 16, 2021, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate to a semiconductor device and a method of manufacturing the same.
In a three-dimensional semiconductor memory, there arises a problem that an insulator for dividing an electrode layer contacts a columnar portion that includes a charge storage layer and a channel semiconductor layer.
Embodiments will now be explained with reference to the accompanying drawings. In
In one embodiment, a semiconductor device includes a plurality of first electrode layers spaced from one another in a first direction, and a plurality of second electrode layers provided above the first electrode layers, and spaced from one another in the first direction. The device further includes a first columnar portion extending in the first direction in the plurality of first electrode layers, and including a first semiconductor layer, and a second columnar portion provided on the first columnar portion, extending in the first direction in the plurality of second electrode layers, and including a second semiconductor layer. The device further includes a first charge storage layer provided between the plurality of first electrode layers and the first semiconductor layer, and a second charge storage layer provided between the plurality of second electrode layers and the second semiconductor layer. The second semiconductor layer is directly provided on the first semiconductor layer, or is provided on the first semiconductor layer via another semiconductor layer. The first columnar portion includes a first portion having a first width in a second direction intersecting the first direction, and a second portion provided above the first portion and having a second width larger than the first width in the second direction. The second columnar portion includes a third portion having a third width in the second direction, and a fourth portion provided above the third portion and having a fourth width larger than the third width in the second direction.
The semiconductor device in
The memory substrate 1 includes a substrate 11, a stacked film 12, and a plurality of columnar portions 13. The columnar portions 13 are each an example of a first columnar portion. The memory substrate 2 includes a stacked film 21, a plurality of columnar portions 22, an embedded insulator 23, an interconnection layer 24, and a passivation insulator 25. The columnar portions 22 are each an example of a second columnar portion. The embedded insulator 23 is an example of a third insulator.
The stacked film 12 includes a plurality of insulators 31 and a plurality of electrode layers 32. Each of the columnar portions 13 includes a memory insulator 33, a channel semiconductor layer 34, and a core insulator 35. The channel semiconductor layer 34 includes a semiconductor layer 34a and a semiconductor layer 34b. The electrode layer 32 is an example of a first electrode layer. The semiconductor layer 34a is an example of a first semiconductor layer. A charge storage layer (described below) in the memory insulator 33 is an example of a first charge storage layer.
The stacked film 21 includes a plurality of insulators 41 and a plurality of electrode layers 42. Each of the columnar portions 22 includes a memory insulator 43, a channel semiconductor layer 44, and a core insulator 45. The channel semiconductor layer 44 includes a semiconductor layer 44a, a semiconductor layer 44b, and a semiconductor layer 44c. The electrode layer 42 is an example of a second electrode layer. The semiconductor layer 44a is an example of a second semiconductor layer. A charge storage layer (described below) in the memory insulator 43 is an example of a second charge storage layer.
Further details of the semiconductor device in
The substrate 11 is a semiconductor substrate such as a silicon substrate. In
The stacked film 12 includes the plurality of insulators 31 and the plurality of electrode layers 32 alternately provided on the substrate 11. The electrode layers 32 are spaced from one another in the Z-direction above the substrate 11. The electrode layers 32 each function as a word line or a selection line. Each of the insulators 31 is an SiO2 film (silicon oxide film), for example. Each of the electrode layers 32 is a metal layer including a TiN film (titanium nitride film) as a barrier metal layer and including a W (tungsten) layer as an electrode material layer, for example.
The columnar portions 13 are formed on the substrate 11 in the stacked film 12, and each have a columnar shape extending in the Z-direction. Each of the columnar portions 13 includes the memory insulator 33, the channel semiconductor layer 34, and the core insulator 35 formed in this order in the stacked film 12. The columnar portions 13 in the present embodiment each have a shape close to a circular columnar shape, and a planar shape of the columnar portion 13 is a circular shape. Note that a side face of each of the columnar portions 13 in the present embodiment is inclined with respect to the Z-direction, and a diameter in the vicinity of an upper end of the columnar portion 13 is larger than a diameter in the vicinity of a lower end of the columnar portion 13. Therefore, each of the columnar portions 13 in the present embodiment has a diameter that increases in the Z-direction. That is, a diameter of each of the columnar portions 13 at a height increases as the height increases. In
From another viewpoint, when two portions respectively having different heights in each of the columnar portions 13 are paid attention to, a width in the X-direction of the higher portion is larger than a width in the X-direction of the lower portion. The lower portion and the width thereof are an example of a first portion and a first width. The higher portion and the width thereof are an example of a second portion and a second width.
The memory insulator 33 is formed on respective side faces of the insulators 31 and the electrode layers 32 in the stacked film 12. The memory insulator 33 includes an SiO2 film as a block insulator, includes an SiN film (silicon nitride film) as a charge storage layer, and includes an SiO2 film or an SiON film (silicon oxynitride film) as a tunnel insulator, for example. The charge storage layer may be a semiconductor layer such as a polysilicon layer.
The semiconductor layer 34a in the channel semiconductor layer 34 is formed on a side face of the memory insulator 33 and an upper face of the substrate 11. The core insulator 35 is formed on a side face and an upper face of the semiconductor layer 34a. The semiconductor layer 34b in the channel semiconductor layer 34 is formed on the side face of the semiconductor layer 34a and an upper face of the core insulator 35, and contacts the semiconductor layer 34a. The semiconductor layers 34a and 34b are each an Si (silicon) layer such as a polysilicon layer. The core insulator 35 is an SiO2 film, for example.
The stacked film 21 includes the plurality of insulators 41 and the plurality of electrode layers 42 alternately provided on the stacked film 12. The electrode layers 42 are spaced from one another in the Z-direction above the plurality of electrode layers 32. The electrode layers 42 each function as a word line or a selection line. Each of the insulators 41 is an SiO2 film, for example. Each of the electrode layers 42 is a metal layer including a TiN film as a barrier metal layer and including a W layer as an electrode material layer, for example.
The columnar portions 22 are respectively formed on the columnar portions 13 in the stacked film 21, and each have a columnar shape extending in the Z-direction. Specifically, each of the columnar portions 22 is formed on the corresponding columnar portion 13, and is electrically connected to the corresponding columnar portion 13. Each of the columnar portions 22 includes the memory insulator 43, the channel semiconductor layer 44, and the core insulator 45 formed in this order in the stacked film 21. The columnar portions 22 in the present embodiment each have a shape close to a circular columnar shape, and a planar shape of the columnar portion 22 is a circular shape. Note that a side face of each of the columnar portions 22 in the present embodiment is inclined with respect to the Z-direction, and a diameter in the vicinity of an upper end of the columnar portion 22 is smaller than a diameter in the vicinity of a lower end of the columnar portion 22. Therefore, each of the columnar portions 22 in the present embodiment has a diameter that decreases in the Z-direction. That is, a diameter of each of the columnar portions 22 at a height decreases as the height increases. In
From another viewpoint, when two portions respectively having different heights in each of the columnar portions 22 are paid attention to, a width in the X-direction of the higher portion is smaller than a width in the X-direction of the lower portion. The lower portion and the width thereof are an example of a third portion and a third width. The higher portion and the width thereof are an example of a fourth portion and a fourth width.
The memory insulator 43 is formed on respective side faces of the insulators 41 and the electrode layers 42 in the stacked film 21. The memory insulator 43 includes an SiO2 film as a block insulator, includes an SiN film as a charge storage layer, and includes an SiO2 film or an SiON film as a tunnel insulator, for example. The charge storage layer may be a semiconductor layer such as a polysilicon layer.
The semiconductor layer 44a in the channel semiconductor layer 44 is formed on a side face of the memory insulator 43 and a lower face of the interconnection layer 24. The core insulator 45 is formed on a side face and a lower face of the semiconductor layer 44a. The semiconductor layer 44b in the channel semiconductor layer 44 is formed on the side face of the semiconductor layer 44a and a lower face of the core insulator 45, and contacts the semiconductor layer 44a. The semiconductor layer 44c in the channel semiconductor layer 44 is formed on respective lower faces of the semiconductor layers 44a and 44b and respective upper faces of the semiconductor layers 34a and 34b, and contacts the semiconductor layers 44a, 44b, 34a, and 34b. Therefore, the channel semiconductor layer contacts the channel semiconductor layer 34, and is electrically connected to the channel semiconductor layer 34. The semiconductor layer 44c is a joint portion P1 that couples the channel semiconductor layer 34 and the channel semiconductor layer 44 to each other. The semiconductor layers 44a, 44b, and 44c are each an Si layer such as a polysilicon layer. The core insulator 45 is an SiO2 film, for example.
The embedded insulator 23 is formed in only the stacked film 21 out of the stacked films 12 and 21, and extends in the Y-direction and the Z-direction. The semiconductor device of the present embodiment includes a plurality of embedded insulators 23.
The interconnection layer 24 is formed on the stacked film 21, the columnar portions 22, and the embedded insulators 23, and is electrically connected to the channel semiconductor layer 44 in each of the columnar portions 22. The interconnection layer 24 may include only one of a semiconductor layer and a metal layer, or may include both the semiconductor layer and the metal layer. The interconnection layer 24 includes a polysilicon layer as the semiconductor layer, and includes a W layer, an Al (aluminum) layer, and a Cu (copper) layer as the metal layer.
The passivation insulator 25 is formed on the interconnection layer 24. The passivation insulator 25 is a stacked film including an SiO2 film and other insulators, for example.
An upper face of the channel semiconductor layer 34 in each of the columnar portion 13 may have a solid shape such as a circular shape, or may have a hollow shape such as an annular shape. The upper face of the channel semiconductor layer 34 in the present embodiment has a solid shape because it is formed of the semiconductor layers 34a and 34b. Similarly, a lower face of the channel semiconductor layer 44 in each of the columnar portions 22 may have a solid shape, or may have a hollow shape. The lower face of the channel semiconductor layer 44 in the present embodiment has a solid shape because it is formed of the semiconductor layer 44c.
The upper face of the semiconductor layer 34a in the present embodiment has a hollow shape, and the lower face of the semiconductor layer 44a in the present embodiment has a hollow shape. Each of the columnar portions 13 includes the semiconductor layer 34b in the upper face of the semiconductor layer 34a, and each of the columnar portions 22 includes the semiconductor layer 44b in the lower face of the semiconductor layer 44a. The semiconductor layers 44a and 44b in the present embodiment are respectively formed on the semiconductor layers 34a and 34b via the semiconductor layer 44c.
The channel semiconductor layer 44 in the present embodiment includes the semiconductor layer 44c as the joint portion P1. Accordingly, the diameter of the lower face of the channel semiconductor layer 44 (the semiconductor layer 44c) is larger than the diameter of the upper face of the corresponding channel semiconductor layer 34, and is further larger than the diameter of an upper face of the corresponding columnar portion 13. This makes it possible to electrically connect the channel semiconductor layer 34 and the channel semiconductor layer 44 to each other in a preferred manner even if a position shift occurs between the columnar portion 13 and the columnar portion 22. The channel semiconductor layer 44 may not include the joint portion P1.
Each of the electrode layers 32 includes a barrier metal layer 32a and an electrode material layer 32b. The barrier metal layer 32a is a TiN film, for example. The electrode material layer 32b is a W layer, for example. Each of the electrode layers 32 is formed on an upper face of the insulator 31, a lower face of the insulator 31, and a side face of the block insulator 33a via a block insulator 36. The block insulator 36 is an aluminum oxide film, for example.
Each of the electrode layers 42 includes a barrier metal layer 42a and an electrode material layer 42b. The barrier metal layer 42a is a TiN film, for example. The electrode material layer 42b is a W layer, for example. Each of the electrode layers 42 is formed on a lower face of the insulator 41, an upper face of the insulator 41, and a side face of the block insulator 43a via a block insulator 46. The block insulator 46 is an aluminum oxide film, for example.
The semiconductor device of the present embodiment further includes one region R1 and a plurality of regions R2, as illustrated in
Each of the embedded insulators 51 is formed in the stacked films 12 and 21, and extends in the Y-direction and the Z-direction.
Each of the embedded insulators 23 is formed in only the stacked film 21 out of the stacked films 12 and 21, and extends in the Y-direction and the Z-direction, as described above.
The region R1 corresponds to the finger of the three-dimensional semiconductor memory.
Each of the regions R2 corresponds to the page of the three-dimensional semiconductor memory.
The semiconductor device (
On the other hand, the semiconductor device (
The columnar portions 13 and 22 in the comparative example are respectively formed of the same memory insulators 33, channel semiconductor layers 34, and core insulators 35. A symbol P2 indicates a joint portion between the columnar portion 13 and the columnar portion 22. Each of the embedded insulators 23 in the comparative example contacts the columnar portions 22 in the stacked film 21, as illustrated in
In the semiconductor device (
Then referring to
In the semiconductor device in the comparative example, each of the columnar portions 22 has a diameter that increases in the Z-direction. Therefore, a diameter in the vicinity of an upper end of the columnar portion 22 is larger than a diameter in the vicinity of a lower end of the columnar portion 22. On the other hand, in the semiconductor device of the present embodiment, each of the columnar portions 22 has the diameter that decreases in the Z-direction. Therefore, the diameter in the vicinity of the upper end of the columnar portion 22 is smaller than the diameter in the vicinity of the lower end of the columnar portion 22. As a result, the diameter of the columnar portion 22 illustrated in
In both the present embodiment and the comparative example, each of the embedded insulators 23 is arranged in the vicinity of an upper face of the stacked film 21. Therefore, the embedded insulator 23 is arranged in the vicinity of the upper end of each of the columnar portions 22. In the comparative example, the diameter in the vicinity of the upper end of the columnar portions 22 is large, whereby the embedded insulator 23 is difficult to arrange not to contact the columnar portions 22. Accordingly, in the comparative example, there easily arises a problem that the embedded insulator 23 contacts the columnar portions 22. Alternatively, in the comparative example, a layout may be designed such that the embedded insulator 23 contacts the columnar portions 22, and the columnar portions 22 that contact the embedded insulator 23 may not be used for a memory cell. In the former case, a defect may occur in each of the columnar portions 22. In the latter case, waste may occur in each of the columnar portions 22.
On the other hand, in the present embodiment, the diameter in the vicinity of the upper end of each of the columnar portions 22 is small, whereby the embedded insulator 23 is easy to arrange not to contact the columnar portions 22. Therefore, the present embodiment makes it possible to easily prevent the embedded insulator 23 from contacting the columnar portions 22, thereby making it possible to avoid the above-described problem as in the comparative example. This makes it possible to increase respective densities of the columnar portions 22 in an XY plane when the plurality of columnar portions 22 are arranged in a two-dimensional array shape, thereby making it possible to increase an integration degree of the semiconductor device.
In the comparative example, there may easily occur respective defects in the columnar portions 13 and 22 due to the joint portion P2. On the other hand, the joint portion P1 in the present embodiment has a simpler structure than that of the joint portion P2 in the comparative example, which makes it possible to suppress the defects.
First, a substrate 11 is prepared, a stacked film 12 is formed on the substrate 11, and a plurality of memory holes MH1 are formed in the stacked film 12 (
Then, a memory insulator 33, a semiconductor layer 34a, and a core insulator 35 are formed in this order in each of the memory holes MH1 (
Then, by lithography and RIE, a hole H1 is formed in the core insulator 35 in each of the memory holes MH1, and a semiconductor layer 34b is formed in the hole H1 (
Then, the memory substrate 1 and the memory substrate 2 are bonded to each other (
In a step in
Then, the substrate 26, the insulator 27, the insulator 28, and the insulator 29 are removed (
Then, a plurality of slits ST (see
The plurality of slits ST are formed to extend in the Y-direction and the Z-direction and to be adjacent to one another in the X-direction. The slits ST are respectively filled with embedded insulators 51 after the sacrificial layers 37 and 47 are respectively replaced with the electrode layers 32 and 42 (see
Each of the electrode layers 32 is formed by forming a block insulator 36 in the space and then forming a barrier metal layer 32a and an electrode material layer 32b in this order in the space, for example (see
The sacrificial layers 37 and 47 may be respectively replaced with the electrode layers 32 and 42 after at least a portion of each of the columnar portions 13 and 22 is formed before the memory substrate 1 and the memory substrate 2 are bonded to each other. For example, the replacement may be performed using the slits ST by forming a portion of each of the slits ST in the stacked film 12 and another part of each of the slit ST in the staked film 21 after the columnar portions 13 and are completed in the step illustrated in
Then, a hole SH is formed in the stacked film 21 by lithography and RIE, and an embedded insulator 23 is formed in the hole SH (
Then, an interconnection layer 24 is formed on the stacked film 21, the columnar portions 22, and the embedded insulators 23, and a passivation insulator 25 is formed on the interconnection layer 24 (
As described above, the semiconductor device of the present embodiment is manufactured by bonding the memory substrate 1 including the columnar portions 13 and the memory substrate 2 including the columnar portions 22 to each other. The semiconductor device of the present embodiment includes the columnar portions 13 provided on the substrate 11 and each having a diameter that increases in the Z-direction and the columnar portions 22 respectively provided on the columnar portions 13 and each having a diameter that decreases in the Z-direction. Therefore, the present embodiment makes it possible to prevent each of the embedded insulators 23 for dividing each of the electrode layers 42 from contacting the columnar portions 22.
When the memory substrate 1 and the memory substrate 2 are bonded to each other, the memory substrate 1 and the memory substrate 2 may be in a state of a wafer, or may be in a state of a chip obtained by dicing the wafer. The memory substrate 1 and the memory substrate 2 are manufactured by being bonded to each other in the state of the wafer. Therefore, after the memory substrate 1 and the memory substrate 2 in the present embodiment are bonded to each other, the memory substrate 1 and the memory substrate 2 are diced.
The semiconductor device of the present embodiment has a structure in which the semiconductor layer 44c is removed from the semiconductor device of the first embodiment. Therefore, upper faces of semiconductor layers 34a and 34b in each of columnar portions 13 respectively contact lower faces of semiconductor layers 44a and 44b in a corresponding columnar portion 22. In the present embodiment, an upper face of a channel semiconductor layer 34 and a lower face of a channel semiconductor layer 44 each have a solid shape.
The upper face of the semiconductor layer 34a in the present embodiment has a hollow shape, and the lower face of the semiconductor layer 44a in the present embodiment also has a hollow shape. Each of the columnar portions 13 includes the semiconductor layer 34b in the upper face of the semiconductor layer 34a, and each of the columnar portions 22 includes the semiconductor layer 44b in the lower face of the semiconductor layer 44a. The semiconductor layers 44a and 44b in the present embodiment are respectively directly formed on the semiconductor layers 34a and 34b.
The semiconductor device of the present embodiment can be manufactured by omitting the step illustrated in
The semiconductor device of the first modification has a structure in which the semiconductor layer 34b is removed from the semiconductor device of the second embodiment. Therefore, lower faces of semiconductor layers 44a and 44b in each of columnar portions 22 respectively contact upper faces of a channel semiconductor layer 34 (a semiconductor layer 34a) and a core insulator 35 in a corresponding columnar portion 13. In the modification, a lower face of a channel semiconductor layer 44 has a solid shape, and the upper face of the channel semiconductor layer 34 has a hollow shape.
The upper face of the semiconductor layer 34a in the modification has a hollow shape, and the lower face of the semiconductor layer 44a in the modification also has a hollow shape. Each of the columnar portions 13 includes the core insulator 35 in the upper face of the semiconductor layer 34a, and each of the columnar portions 22 includes the semiconductor layer 44b in the lower face of the semiconductor layer 44a. The semiconductor layer 44a in the modification is directly formed on the semiconductor layer 34a.
The semiconductor device of the modification can be manufactured by omitting the steps illustrated in
The semiconductor device of the modification has a structure in which the semiconductor layer 44b is removed from the semiconductor device of the second embodiment. Therefore, upper faces of semiconductor layers 34a and 34b in each of columnar portions 13 respectively contact upper faces of a channel semiconductor layer 44 (a semiconductor layer 44a) and a core insulator 45 in a corresponding columnar portion 22. In the modification, an upper face of a channel semiconductor layer 34 has a solid shape, and a lower face of the channel semiconductor layer 44 has a hollow shape.
The upper face of the semiconductor layer 34a in the modification has a hollow shape, and the lower face of the semiconductor layer 44a in the modification also has a hollow shape. Each of the columnar portions 13 includes the semiconductor layer 34b in the upper face of the semiconductor layer 34a, and each of the columnar portions 22 includes a core insulator 45 in the lower face of the semiconductor layer 44a. The semiconductor layer 44a in the modification is directly formed on the semiconductor layer 34a.
The semiconductor device of the modification can be manufactured by omitting the steps illustrated in
The semiconductor device of the present embodiment is manufactured by bonding a memory substrate 1 and a memory substrate 2a to each other and bonding the memory substrate 2a and a memory substrate 2b to each other.
The memory substrate 1 in the present embodiment (
A structure of electrode layers 42 and columnar portions 22 in each of memory substrates 2a and 2b in the present embodiment is similar to the structure of the electrode layers 42 and the columnar portions 22 in the memory substrate 2 illustrated in
Therefore, each of the columnar portions 22 in each of the memory substrates 2a and 2b in the present embodiment has a shape close to a circular columnar shape, and a planar shape of each of the columnar portions 22 is a circular shape. Note that a side face of the columnar portion 22 in the present embodiment is inclined with respect to a Z-direction, and a diameter in the vicinity of an upper end of the columnar portion 22 is smaller than a diameter in the vicinity of a lower end of the columnar portion 22. Therefore, each of the columnar portions 22 in the present embodiment has a diameter that decrease in the Z-direction. That is, a diameter of each of the columnar portions 22 at a height decreases as the height increases. In
From another viewpoint, when two portions respectively having different heights in each of the columnar portions 22 are paid attention to, a width in the X-direction of the higher portion is smaller than a width in the X-direction of the lower portion. The lower portion and the width thereof are respectively examples of a third or fifth portion and a third or fifth width. The higher portion and the width thereof are examples of a fourth or sixth portion and a fourth or sixth width.
The semiconductor device of the present embodiment can be manufactured by changing the method of manufacturing the semiconductor device of the first embodiment in the following manner.
First, memory substrates 1, 2a, and 2b in the present embodiment are manufactured in a similar manner to the memory substrates 1, 2, and 2 in the steps illustrated in
Then, sacrificial layers 37 and 47 in the memory substrates 1, 2a, and 2b in the present embodiment are respectively replaced with electrode layers 32 and 42 in a similar manner to the sacrificial layers 37 and 47 in the memory substrates 1 and 2 in the step illustrated in
Then, the memory substrate 2b in the present embodiment is processed in a similar manner to the memory substrate 2 illustrated in
The semiconductor device of the present embodiment may include a plurality of memory substrates 2a between the memory substrate 1 and the memory substrate 2b. In this case, the semiconductor device is manufactured by repeating the steps illustrated in
The memory substrates 1, 2a, and 2b in the present embodiment may have the same structure as that of the memory substrate 1 and 2 in the second embodiment or the modification thereto for columnar portions 13 and 22.
The semiconductor device of the present embodiment includes an interconnection layer 52, a post portion 53, a post portion 54, an inter layer dielectric 55, an inter layer dielectric 56, a plurality of contact plugs 57, a contact plug 58, and a stepped region R in addition to components in the semiconductor device of the second embodiment. The semiconductor device of the present embodiment further includes a connection semiconductor layer 38 in a columnar portion 13. In
An embedded insulator 51 and the interconnection layer 52 are formed in stacked films 12 and 21. Specifically, the embedded insulator 51 and the interconnection layer 52 are formed in this order in a slit ST (see
The post portion 53 is formed in the stacked film 12 on a substrate 11, and the post portion 54 is formed on the post portion 53 in the stacked film 21. The post portions 53 and 54 are each an SiO2 film, for example. The post portions 53 and 54 each have a columnar shape extending in the Z-direction. The post portion 53 in the present embodiment has a diameter that increases in the Z-direction, and the post portion 54 in the present embodiment has a diameter that decreases in the Z-direction.
The stepped region R is formed in a portion of the stacked film 21. In the stepped region R, insulators 41 and electrode layers 42 are processed in a stepped shape. The inter layer dielectric 55 is formed on the stepped region R in the stacked film 21 and on the post portion 54 in the stacked film 21. The inter layer dielectric 56 is formed on the stacked film 21, a columnar portion 22, an embedded insulator 23, the embedded insulator 51, the interconnection layer 52, and the inter layer dielectric 55.
The contact plugs 57 are formed in the inter layer dielectrics 55 and 56 and on the stepped region R in the stacked film 21. Each of the contact plugs 57 is formed on an upper face of the corresponding electrode layer 42, and is electrically connected to the corresponding electrode layer 42. The contact plug 58 is formed in the inter layer dielectric 56 and the memory insulator 43 and on a channel semiconductor layer 44, and is electrically connected to the channel semiconductor layer 44.
In the columnar portion 13 in the present embodiment, the connection semiconductor layer 38 is formed in the stacked film 12 on the substrate 11. The connection semiconductor layer 38 is an Si layer formed by epitaxial growth from a substrate 11, for example. A memory insulator 33, a channel semiconductor layer 34, and a core insulator 35 are formed on the connection semiconductor layer 38. The memory insulator 33 is formed on respective side faces of insulators 31 and electrode layers 32 in the stacked film 12. A semiconductor layer 34a in the channel semiconductor layer 34 is formed on a side face of the memory insulator 33 and an upper face of the connection semiconductor layer 38, and contacts the connection semiconductor layer 38. The core insulator 35 is formed on a side face and an upper face of the semiconductor layer 34a. A semiconductor layer 34b in the channel semiconductor layer 34 is formed on the side face of semiconductor layer 34a and an upper face of the core insulator 35, and contacts the semiconductor layer 34a.
For the method illustrated in
First, a substrate 11 is prepared, and a stacked film 12 is formed on the substrate 11 (
Then, a hole K1 is formed in the stacked film 12 by lithography and RIE, a post portion 53 is formed in the hole K1, a memory hole MH1 is formed in the stacked film 12 by lithography and RIE, and a columnar portion 13 is formed in the memory hole MH1 (
Then, a memory substrate 1 and a memory substrate 2 are bonded to each other (
Then, the substrate 26 is removed (
Then, a slit ST is formed in the stacked films 21 and 12 by lithography and RIE, sacrificial layers 37 and 47 are removed by wet etching from the slit ST, and electrode layers 32 and 42 are respectively formed in spaces obtained by removing the sacrificial layers 37 and 47 (
Then, an inter layer dielectric 56 is formed on the stacked film 21, the columnar portion 22, the embedded insulator 23, the embedded insulator 51, the interconnection layer 52, and the inter layer dielectric 55 (
As described above, the semiconductor device of the present embodiment is manufactured by bonding the memory substrate 1 including the columnar portion 13 and the memory substrate 2 including the columnar portion 22 to each other. The semiconductor device of the present embodiment includes the columnar portion 13 provided on the substrate 11 and having a diameter that increases in the Z-direction and the columnar portion 22 provided on the columnar portion 13 and having a diameter that decreases in the Z-direction. Therefore, the present embodiment makes it possible to prevent the embedded insulator 23 for dividing each of the electrode layers 42 from contacting the columnar portion 22, like the first to third embodiments.
The memory substrates 1 and 2 in the present embodiment may respectively have the same structures as those of the memory substrates 1 and 2 in the first embodiment and the same structure as those of the memory substrates 1 and 2 in the modification to the second embodiment for the columnar portions 13 and 22.
In the first to fourth embodiments, the semiconductor device in each of the embodiments may be a three-dimensional semiconductor memory of a type different from that of the above-described three-dimensional semiconductor memory. For example, charge storage layers 33b and 43b may be each a layer of a floating gate type instead of a layer of a charge trap type. The charge storage layers 33b and 43b may be provided outside the columnar portions 13 and 22 instead of being provided in the columnar portions 13 and 22. A shape in an XY cross portion of each of the columnar portions 13 and 22 may be a shape (e.g., an elliptic shape or a square shape) other than a circle.
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 devices and methods described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the devices and methods 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.
Number | Date | Country | Kind |
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2021-042761 | Mar 2021 | JP | national |