CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-146059, filed on Aug. 31, 2020, the entire contents of which are incorporated herein by reference.
FIELD
Embodiments described herein relate generally to a semiconductor storage device.
BACKGROUND
A semiconductor storage device may include a substrate, a plurality of conductive layers stacked in a direction intersecting with the surface of the substrate, a semiconductor layer facing these plurality of conductive layers, and a gate insulating layer formed between the conductive layers and the semiconductor layer. The gate insulating layer includes a memory unit capable of storing data such as, for example, an insulating charge storage layer such as silicon nitride (Si3N4) or a conductive charge storage layer such as a floating gate.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view illustrating a configuration of a memory die MD according to a first embodiment.
FIG. 2 is a schematic bottom view illustrating a configuration of a chip CM.
FIG. 3 is a schematic bottom view illustrating a partial configuration of the chip CM.
FIG. 4 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 5 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 6 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 7 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 8 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 9 is a schematic cross-sectional view illustrating a partial configuration of the chip CM.
FIG. 10 is a schematic cross-sectional view illustrating a method of manufacturing the semiconductor storage device according to the first embodiment.
FIG. 11 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 12 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 13 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 14 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 15 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 16 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 17 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 18 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 19 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 20 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 21 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 22 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 23 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 24 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 25 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 26 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 27 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 28 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 29 is a schematic cross-sectional view illustrating a configuration of a semiconductor storage device according to a second embodiment.
FIG. 30 is a schematic cross-sectional view illustrating a method of manufacturing the semiconductor storage device according to the second embodiment.
FIG. 31 is a schematic cross-sectional view illustrating the manufacturing method.
FIG. 32 is a schematic cross-sectional view illustrating a configuration of a semiconductor storage device according to a third embodiment.
FIG. 33 is a schematic cross-sectional view illustrating a method of manufacturing the semiconductor storage device according to the third embodiment.
FIG. 34 is a schematic cross-sectional view illustrating a method of manufacturing a semiconductor storage device according to a fourth embodiment.
DETAILED DESCRIPTION
At least one embodiment provides a semiconductor storage device which may be suitably manufactured.
In general, according to at least one embodiment, a semiconductor storage device includes a substrate, a plurality of first conductive layers arranged in a first direction intersecting with a surface of the substrate, a first semiconductor layer that extends in the first direction and faces the plurality of first conductive layers, a first gate insulating film that extends in the first direction and covers an outer peripheral surface of the first semiconductor layer, a first insulating layer that extends in the first direction and has an outer peripheral surface covered with the first semiconductor layer, and a second conductive layer that is farther from the substrate than the plurality of first conductive layers and is connected to one end in the first direction of the first semiconductor layer. The first semiconductor layer includes a first region facing the plurality of first conductive layers and a second region farther from the substrate than the first region. The second conductive layer is connected to an inner peripheral surface and an outer peripheral surface of the second region of the first semiconductor layer and is in contact with one end in the first direction of the first insulating layer.
Next, a semiconductor storage device according to at least one embodiment is described in detail with reference to the drawings. Furthermore, the following embodiments are merely examples, and are not intended to limit the present disclosure. Further, the following drawings are schematic, and for convenience of explanation, some configurations may be omitted. Further, the same reference numerals may be given to parts common to a plurality of embodiments, and descriptions thereof may be omitted.
Further, when referring to “semiconductor storage device” in this specification, it may mean a memory die, or may mean a memory system including a controller die such as a memory chip, a memory card, or a solid state drive (SSD). Moreover, the semiconductor storage device may mean a configuration including a host computer such as a smart phone, a tablet terminal, or a personal computer.
Further, in this specification, when a first configuration is referred to as being “electrically connected” to a second configuration, the first configuration may be directly connected to the second configuration, or the first configuration may be connected to the second configuration via a wiring, a semiconductor member, or a transistor. For example, when three transistors are connected in series, a first transistor is “electrically connected” to a third transistor even if a second transistor is in the OFF state.
Further, in the present specification, a predetermined direction parallel to the surface of a substrate is referred to as the X direction, a direction parallel to the surface of the substrate and perpendicular to the X direction is referred to as the Y direction, and a direction perpendicular to the surface of the substrate is referred to as the Z direction.
Further, in this specification, a direction along a predetermined surface is referred to as a first direction, a direction intersecting with the first direction along the predetermined surface is referred to as a second direction, and a direction intersecting with the predetermined surface is referred to as a third direction. The first direction, the second direction, and the third direction may or may not correspond to any of the X direction, the Y direction, and the Z direction.
Further, in this specification, expressions such as “upper (above)” and “lower (below)” are on the basis of the substrate. For example, a direction farther away from the substrate along the Z direction is referred to as “upper”, and a direction closer to the substrate along the Z direction is referred to as “lower”. Further, when referring to a lower surface or lower end with respect to a certain configuration, it means a surface or end of this configuration on the substrate side, and when referring to an upper surface or upper end thereof, it means a surface or end of this configuration opposite to the substrate. Further, a surface intersecting with the X direction or the Y direction is referred to as a side surface.
Further, in this specification, when referring to the “width,” “length,” or “thickness” in a predetermined direction with respect to a configuration or a member, it may mean the width, the length, or the thickness in the cross section observed by a scanning electron microscopy (SEM) or transmission electron microscopy (TEM).
First Embodiment
[Structure of Memory Die MD]
FIG. 1 is a schematic exploded perspective view illustrating a configuration example of a semiconductor storage device according to at least one embodiment. The semiconductor storage device according to at least one embodiment includes a memory die MD. The memory die MD includes a chip CM including a memory cell array and a chip CP including a peripheral circuit.
A plurality of bonding pad electrodes PX are provided on the upper surface of the chip CM. Further, a plurality of first laminated electrodes PI1 are provided on the lower surface of the chip CM. Further, a plurality of second laminated electrodes PI2 are provided on the surface of the chip CP. Hereinafter, with respect to the chip CM, the surface on which the plurality of first laminated electrodes PI1 are provided is referred to as a surface, and the surface on which the plurality of bonding pad electrodes PX are provided is referred to as a back surface. Further, with respect to the chip CP, the surface on which the plurality of second laminated electrodes PI2 are provided is referred to as a surface, and the surface opposite to that surface is referred to as a back surface. In the illustrated example, the surface of the chip CP is provided above the back surface of the chip CP, and the back surface of the chip CM is provided above the surface of the chip CM.
The chip CM and the chip CP are arranged such that the surface of the chip CM and the surface of the chip CP face each other. The plurality of first laminated electrodes PI1 are provided corresponding to the plurality of second laminated electrodes PI2, respectively, and are arranged at positions where they may be laminated to the plurality of second laminated electrodes PI2. The first laminated electrodes PI1 and the second laminated electrodes PI2 function as laminated electrodes that laminates the chip CM and the chip CP and electrically connects the chip CM and the chip CP. The bonding pad electrodes PX function as electrodes for electrically connecting the memory die MD to a controller die (not illustrated).
Furthermore, in the example of FIG. 1, the corner portions a1, a2, a3, and a4 of the chip CM correspond to the corner portions b1, b2, b3, and b4 of the chip CP, respectively.
FIG. 2 is a schematic bottom view illustrating a configuration of the chip CM. FIG. 3 is a schematic bottom view illustrating a configuration of portion designated by A in FIG. 2 in an enlarged manner. FIG. 4 is a schematic cross-sectional view of a structure illustrated in FIG. 3 taken along line B-B′ and viewed along the direction of the arrow. FIG. 5 is a schematic cross-sectional view illustrating a configuration of portion designated by C in FIG. 4 in an enlarged manner. FIG. 6 is a schematic cross-sectional view of a structure illustrated in FIG. 3 taken along line D-D′ and viewed along the direction of the arrow.
FIG. 7 is a schematic cross-sectional view of a structure illustrated in FIG. 3 taken along lines E-E′ and F-F′ and viewed along the direction of the arrow. Furthermore, FIG. 7 also illustrates a structure in a memory cell array outer peripheral region RMCAE to be described below. FIG. 8 is a schematic cross-sectional view illustrating a partial configuration of the semiconductor storage device. FIG. 9 is a schematic cross-sectional view of a structure illustrated in FIG. 2 taken along line G-G′ and viewed along the direction of the arrow.
[Structure of Chip CM]
For example, as illustrated in FIG. 2, the chip CM includes four memory cell array regions RMCA arranged in the X and Y directions, a memory cell array outer peripheral region RMCA formed along the outer periphery of each memory cell array region RMCA, a plurality of bonding pad electrode regions Rex corresponding to the plurality of bonding pad electrodes PX, and an edge seal region RE formed along the outer edge portion of the chip CM.
The memory cell array area RMCA includes a plurality of memory blocks BLK arranged in the Y direction, a plurality of inter-block structures 140 (FIG. 3) provided respectively between these plurality of memory blocks BLK, and a conductive layer 150 (FIG. 4) formed on the upper surface of the plurality of memory blocks BLK and the plurality of inter-block structures 140. Further, a wiring layer 160 is formed below these plurality of memory blocks BLK. Further, a wiring layer 170 is formed above the conductive layer 150.
For example, as illustrated in FIG. 3, the memory block BLK includes a memory hole region RMH, a through contact region R180 formed at a position different from the memory hole region RMH in the X direction, and a hookup region R190 formed at a position different from the memory hole region RMH and the through contact region R180 in the X direction.
For example, as illustrated in FIG. 4, the memory hole region RMH of the memory block BLK includes a plurality of conductive layers 110 arranged in the Z direction, a plurality of semiconductor layers 120 extending in the Z direction, and a plurality of gate insulating films 130 formed respectively between the plurality of conductive layers 110 and the plurality of semiconductor layers 120.
The conductive layers 110 are a substantially plate-shaped conductive layer extending in the X direction. The conductive layers 110 function as, for example, word lines and gate electrodes of a plurality of memory cells connected thereto. The conductive layers 110 may contain a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). Further, the conductive layers 110 may contain, for example, polycrystalline silicon containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B). An insulating layer 101 such as silicon oxide (SiO2) is formed between the plurality of conductive layers 110 arranged in the Z direction. Further, an insulating layer 102 such as silicon oxide (SiO2) is formed on the upper surface of the conductive layer 110 located at the uppermost position. In the illustrated example, the thickness of the insulating layer 102 in the Z direction is larger than the thickness of the insulating layer 101 in the Z direction.
For example, as illustrated in FIG. 3, the semiconductor layers 120 are arranged in a predetermined pattern in the X direction and the Y direction. The semiconductor layers 120 function as, for example, channel regions of a plurality of memory cells. The semiconductor layers 120 are, for example, a semiconductor layer such as polycrystalline silicon (Si). For example, as illustrated in FIG. 4, the semiconductor layers 120 have a substantially bottomed cylindrical shape and are formed in the central portion thereof with an insulating layer 125 (FIG. 5) such as silicon oxide. Further, the outer peripheral surface of each semiconductor layer 120 is surrounded by the conductive layers 110, and faces the conductive layers 110.
An impurity region containing an N-type impurity such as phosphorus (P) is formed in the lower end portion of the semiconductor layer 120. This impurity region covers the lower end of the insulating layer 125. Further, this impurity region is electrically connected to a bit line BL in the wiring layer 160. The bit line BL is electrically connected to a configuration in the chip CP via the first laminated electrode PI1 described above.
An impurity region containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B) is formed in the upper end portion of the semiconductor layer 120. This impurity region is formed in a substantially cylindrical shape. The upper end portion is located above the upper surface of the insulating layer 102 and the upper end of the insulating layer 125. Further, a part of the outer peripheral surface of this impurity region is in contact with the gate insulating film 130, and a part thereof located above that part is bonded to the conductive layer 150. Further, a part of the inner peripheral surface of this impurity region is in contact with the insulating layer 125, and a part thereof located above that part is bonded to the conductive layer 150. Further, the upper end of this impurity region is bonded to the conductive layer 150.
The gate insulating film 130 has a substantially cylindrical shape that covers the outer peripheral surface of the semiconductor layer 120. For example, as illustrated in FIG. 5, the gate insulating film 130 includes a tunnel insulating film 131, a charge storage film 132, and a block insulating film 133 stacked between the semiconductor layer 120 and the conductive layer 110. The tunnel insulating film 131 and the block insulating film 133 are, for example, an insulating film such as silicon oxide (SiO2). The charge storage film 132 is, for example, a film capable of storing charges such as silicon nitride (Si3N4). The tunnel insulating film 131, the charge storage film 132, and the block insulating film 133 have a substantially cylindrical shape, and extend in the Z direction along the outer peripheral surface of the semiconductor layer 120.
Furthermore, FIG. 5 illustrates an example in which the gate insulating film 130 includes the charge storage film 132 such as silicon nitride. The gate insulating film 130, however, may include, for example, a floating gate such as polycrystalline silicon containing an N-type or P-type impurity.
For example, as illustrated in FIG. 4, each inter-block structure 140 includes a conductive layer 141 extending in the Z direction and the X direction and an insulating layer 142 such as silicon oxide (SiO2) formed on the side surface in the Y direction of the conductive layer 141. The conductive layer 141 may contain a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). The conductive layer 141 functions as, for example, a part of source lines. Furthermore, the upper end portion of the conductive layer 141 may be located above the upper surface of the insulating layer 102. Further, both side surfaces in the X direction and the upper end of the upper end portion of the conductive layer 141 are bonded to the conductive layer 150.
The conductive layer 150 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). Further, the conductive layer 150 may contain, for example, polycrystalline silicon containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B). The conductive layer 150 functions, for example, as a part of source lines.
The conductive layer 150 is in contact with the upper surface of the insulating layer 102, the upper end portion of the semiconductor layer 120, the upper end of the insulating layer 125, and the upper end portion of the conductive layer 141. A portion of the conductive layer 150 that covers the upper surface of the insulating layer 102 is formed substantially flat along the surface of the insulating layer 102. Further, a portion of the conductive layer 150 that covers the upper end portion of the semiconductor layer 120 and the upper end of the insulating layer 125 protrudes upward along the shape of the upper end portion of the semiconductor layer 120. Such protruding portions are formed in the X direction and the Y direction to correspond to each semiconductor layer 120. Further, a portion of the conductive layer 150 that covers the upper end portion of the conductive layer 141 protrudes upward along the shape of the upper end portion of the conductive layer 141. Such protruding portions are formed in the Y direction to correspond to each conductive layer 141, and extends in the X direction.
For example, as illustrated in FIG. 3, the through contact region R180 of the memory block BLK includes two wiring regions R181 arranged in the Y direction, a small through contact area R182 provided between the two wiring regions R181, and an insulating layer 180 such as silicon oxide (SiO2) formed between each wiring region R181 and the small through contact region R182.
For example, as illustrated in FIG. 6, the wiring region R181 of the memory block BLK includes a plurality of the conductive layers 110 arranged in the Z direction. The side surfaces in the Y direction of these plurality of conductive layers 110 are in contact with the insulating layer 180, respectively. These plurality of conductive layers 110 are, for example, a part of the plurality of conductive layers 110 formed in the memory hole region RMH as illustrated in FIG. 3. Furthermore, as illustrated in FIG. 6, in the wiring region R181, a part of the conductive layer 150 is formed on the upper surface of the insulating layer 102.
For example, as illustrated in FIG. 6, the small through contact region R182 of the memory block BLK includes a plurality of insulating layers 110A arranged in the Z direction and a contact 181 extending in the Z direction. Further, a conductive layer 151 may be formed in the small through contact region R182 of the memory block BLK.
The insulating layers 110A are a substantially plate-shaped insulating layer extending in the X direction. The side surfaces in the Y direction of these plurality of insulating layers 110A are in contact with the insulating layer 180, respectively. The insulating layers 110A are, for example, an insulating layer such as silicon nitride (Si3N4). The insulating layer 101 such as silicon oxide (SiO2) is formed between the plurality of insulating layers 110A arranged in the Z direction. Further, the insulating layer 102 such as silicon oxide (SiO2) may be formed on the upper surface of the insulating layer 110A located at the uppermost position.
For example, as illustrated in FIG. 3, the contacts 181 are arranged at predetermined intervals in the X direction. The contact 181 may contain a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). For example, as illustrated in FIG. 6, the contact 181 is electrically connected to a configuration in the chip CP via a wiring 161 in the wiring layer 160 and the first laminated electrode PI1. Furthermore, the upper end portion of the contact 181 is located above the surface of the insulating layer 102. Further, the upper end and the outer peripheral surface of the upper end portion of the contact 181 are in contact with the conductive layer 151. The contact 181 is electrically connected to, for example, the bonding pad electrode PX via the conductive layer 151 and a wiring 171 in the wiring layer 170.
The conductive layer 151 is basically configured in the same manner as the conductive layer 150. However, the conductive layer 151 is electrically independent of the conductive layer 150. Further, the conductive layer 151 is in contact with the upper surface of the insulating layer 102 and the upper end portion of the contact 181. A portion of the conductive layer 151 that covers the upper surface of the insulating layer 102 is formed substantially flat along the upper surface of the insulating layer 102. Further, a portion of the conductive layer 151 that covers the upper end portion of the contact 181 protrudes upward along the shape of the upper end portion of the contact 181. The conductive layers 151 are formed in the X direction to correspond to each contact 181.
For example, as illustrated in FIG. 7, the hookup region R190 of the memory block BLK includes a plurality of the conductive layers 110 arranged in the Z direction and contacts 191 extending in the Z direction.
For example, the plurality of conductive layers 110 of the hookup region R190 are a part of the plurality of conductive layers 110 formed in the memory hole region RMH as illustrated in FIG. 3. For example, as illustrated in FIG. 7, each of the plurality of conductive layers 110 includes a region that overlaps with at least one of the conductive layers 110 located thereunder when viewed in the Z direction and a region that does not overlap with any of the conductive layers 110 located thereunder. Hereinafter, such a structure may be referred to as a substantially stepped structure.
For example, as illustrated in FIG. 3, the contacts 191 are arranged at predetermined intervals in the X direction and the Y direction. The contacts 191 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). For example, as illustrated in FIG. 7, the lower end portion of each contact 191 is electrically connected to a configuration in the chip CP via the wiring 161 in the wiring layer 160 and the first laminated electrode PI1. Further, the upper end portion of the contact 191 is in contact with a part of the corresponding conductive layer 110.
For example, as illustrated in FIG. 7, the memory cell array outer peripheral region RMCAE includes a part of the insulating layer 102. For example, as illustrated in FIG. 7, the insulating layer 102 includes a portion 1021 formed inside the memory cell array region RMCA and a portion 1020 formed outside the memory cell array region RMCA. The thickness of the portion 1020 in the Z direction is smaller than the thickness of the portion 1021 in the Z direction. Further, a step 102S is formed at a connecting portion between the portion 1021 and the portion 1020. The step 102S is formed, for example, along the outer edge of the memory cell array region RMCA.
Further, for example, as illustrated in FIG. 8, the memory cell array outer peripheral region RMCAE includes a contact 185 extending in the Z direction. The contact 185 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). The contact 185 is electrically connected to a configuration in the chip CP via the wiring 161 in the wiring layer 160 and the first laminated electrode PI1. Further, the upper end portion of the contact 185 is in contact with the conductive layer 150. Furthermore, the position of the contact 185 may be adjusted as appropriate.
For example, as illustrated in FIG. 9, the bonding pad electrode region RPX includes a contact 186 extending in the Z direction, a conductive layer 152 in contact with the upper end portion of the contact 186, and the bonding pad electrode PX electrically connected to the conductive layer 152.
The contact 186 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). The contact 186 is electrically connected to a configuration in the chip CP via the wiring 161 in the wiring layer 160 and the first laminated electrode PI1. Further, the upper end portion of the contact 186 may be in contact with the conductive layer 152.
The conductive layer 152 is substantially configured in the same manner as the conductive layer 150. The conductive layer 152, however, is electrically independent of the conductive layer 150. Further, the conductive layer 152 is in contact with the upper surface of the insulating layer 102 and the upper end portion of the contact 186. A portion of the conductive layer 152 that covers the upper surface of the insulating layer 102 is formed substantially flat along the upper surface of the insulating layer 102. Further, a portion of the conductive layer 152 that covers the upper end portion of the contact 186 protrudes upward along the shape of the upper end portion of the contact 186. The conductive layers 152 are formed in the X direction to correspond to each bonding pad electrode PX.
The bonding pad electrode PX may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as aluminum (Al). A part of the upper surface of the bonding pad electrode PX is covered with an insulating layer 103 such as polyimide. Further, a part of the upper surface of the bonding pad electrode PX is exposed to the outside of the memory die MD through an opening formed in the insulating layer 103. Further, a part of the lower surface of the bonding pad electrode PX is in contact with the wiring 171 in the wiring layer 170. The bonding pad electrode PX is electrically connected to a configuration in the chip CP via the wiring 171, the conductive layer 152, and the contact 186.
For example, as illustrated in FIG. 9, the edge seal region RE includes a contact 187 extending in the Z direction, a conductive layer 153 in contact with the upper end portion of the contact 187, and a dummy electrode PXD electrically connected to the conductive layer 153. The contact 187, the conductive layer 153, and the dummy electrode PXD are configured substantially in the same manner as the contact 186, the conductive layer 152, and the bonding pad electrode PX, respectively. However, the contact 187, the conductive layer 153, and the dummy electrode PXD are provided for convenience in a manufacturing process, and do not function as a part of the memory cell array or a part of the peripheral circuit. The contact 187, the conductive layer 153, and the dummy electrode PXD may not be electrically connected to a configuration in the chip CP.
[Structure of Chip CP]
For example, as illustrated in FIG. 4, the chip CP includes a semiconductor substrate 200 and a plurality of transistors Tr provided on the surface of the semiconductor substrate 200. The plurality of transistors Tr are connected to a configuration in the chip CM via the second laminated electrodes PI2 described above, and function as the peripheral circuit used for the control of the memory cell array. In a read operation, for example, this peripheral circuit supplies a voltage to a current path including the bit line BL, the semiconductor layer 120, the conductive layer 150, and the conductive layer 141, and determines data recorded in the memory cell according to whether or not current flows.
[Manufacturing Method]
Next, a method of manufacturing the memory die MD will be described with reference to FIGS. 10 to 28. FIGS. 10 to 28 are schematic cross-sectional views illustrating the manufacturing method. FIGS. 12, 16 to 22, 24, 26 and 28 illustrate the cross section corresponding to FIG. 4. FIGS. 10, 11, 13 to 15, 23, 25 and 27 illustrate the cross section corresponding to FIG. 7.
In the manufacture of the memory die MD according to at least one embodiment, for example, as illustrated in FIG. 10, an insulating layer 104 such as silicon oxide (SiO2) is formed on a semiconductor substrate 100 of a wafer WM. In this process, the insulating layer 104 is formed by, for example, a method such as chemical vapor deposition (CVD). Further, the insulating layer 104 is removed in a region outside the memory cell array region RMCA by a method such as reactive ion etching (RIE) or wet etching.
Next, for example, as illustrated in FIG. 11, a conductive layer 111 and the insulating layer 102 are formed on the upper surfaces of the insulating layer 104 and the semiconductor substrate 100. The conductive layer 111 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). Further, the conductive layer 111 may contain, for example, polycrystalline silicon containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B). This process is performed by, for example, a method such as CVD.
Next, for example, as illustrated in FIGS. 12 and 13, a plurality of insulating layers 110A and insulating layers 101 are formed on the upper surface of the insulating layer 102. This process is performed by, for example, a method such as CVD.
Next, for example, as illustrated in FIG. 14, a part of the plurality of insulating layers 110A and insulating layers 101 is removed to form a substantially stepped structure. In this process, for example, a resist covering the memory cell array region RMCA (FIG. 2) is formed. Next, a part of the insulating layers 110A is selectively removed by a method such as RIE or wet etching using the resist as a mask. Next, a part of the insulating layers 101 is selectively removed by a method such as RIE or wet etching using the resist as a mask. Next, a part of the resist is isotropically removed by a method such as wet etching. Similarly, a part of the insulating layers 110A, a part of the insulating layers 101, and a part of the resist are sequentially removed.
Next, for example, as illustrated in FIG. 15, an insulating layer 105 such as silicon oxide (SiO2) is formed on the upper surface of the stepped structure as illustrated in FIG. 14. This process is performed by, for example, a method such as CVD.
Next, for example, as illustrated in FIG. 16, a plurality of through via holes 120A are formed at positions corresponding to the semiconductor layers 120. The through via holes 120A are through via holes that extend in the Z direction and penetrate the insulating layers 101 and the insulating layers 110A to expose the upper surface of the conductive layer 111. This process is performed by, for example, a method such as RIE.
Next, for example, as illustrated in FIG. 17, the gate insulating film 130, the semiconductor layer 120, and the insulating layer 125 are formed on the inner peripheral surface of each through via hole 120A. This process is performed by, for example, a method such as CVD.
Next, for example, as illustrated in FIG. 18, grooves 140A are formed. The grooves 140A are grooves that extend in the Z direction and the X direction and divide the insulating layers 101 and the insulating layers 110A in the Y direction to expose the upper surface of the conductive layer 111. This process is performed by, for example, a method such as RIE.
Next, for example, as illustrated in FIG. 19, the conductive layers 110 are formed. In this process, the insulating layers 110A are removed through the grooves 140A by, for example, a method such as wet etching. Further, the conductive layers 110 are formed by a method such as CVD.
Next, for example, as illustrated in FIG. 20, the inter-block structures 140 are formed in the grooves 140A. This process is performed by, for example, a method such as CVD or RIE.
Next, for example, as illustrated in FIG. 21, the wiring layer 160 (bit line BL) and the first laminated electrodes PI1 are formed. This process is performed by, for example, a method such as CVD, photolithography, or etching.
Next, for example, as illustrated in FIGS. 22 and 23, the wafer WM corresponding to the chip CM is laminated on a wafer WP corresponding to the chip CP. In this lamination process, for example, the wafer WM is strongly pressed against the wafer WP so as to be in close contact with the wafer WP, and is subjected to a heat treatment. Thus, the wafer WM is laminated on the wafer WP via the first laminated electrodes PI1 and the second laminated electrodes PI2.
Next, for example, as illustrated in FIGS. 24 and 25, the semiconductor substrate 100 and the conductive layer 111 contained in the wafer WM are removed. Further, a part of the insulating layer 102, the gate insulating film 130, and the semiconductor layer 120 is removed to expose the upper ends of the semiconductor layer 120 and the insulating layer 125. This process is performed by, for example, a method such as wet etching or RIE.
Next, for example, as illustrated in FIGS. 26 and 27, a part of the insulating layer 102 and the insulating layer 125 is removed. This process is performed by, for example, a method such as RIE under the condition of silicon oxide (SiO2) being more easily removed than silicon (Si) and tungsten (W). By this process, the upper end of the semiconductor layer 120, the upper end of the conductive layer 141, and the upper end of a contact (not illustrated) are located above the upper surface of the insulating layer 102.
Next, an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B) is injected into the upper end of the semiconductor layer 120 of the structure illustrated in FIGS. 26 and 27. Further, a heat treatment may be performed, and thus, the injected impurity is bonded to silicon (Si) in the semiconductor layer 120.
Next, for example, as illustrated in FIG. 28, a conductive layer 150A is formed on the upper surface of the structure as illustrated in FIGS. 26 and 27. This process is performed by, for example, a method such as CVD.
Next, the conductive layer 150A of the structure illustrated in FIG. 28 is divided into a plurality of portions. This process is performed by, for example, a method such as RIE. By this process, the conductive layer 150 (FIG. 4), the conductive layer 151 (FIG. 6), the conductive layer 152 (FIG. 9), and the conductive layer 153 (FIG. 9) are formed.
After that, the wiring layer 170 and the bonding pad electrodes PX are formed above this structure, and the structure in which the wafers WM and WP are laminated is diced to form the memory die MD.
[Effects]
It is possible to form a semiconductor storage device by forming a memory cell array on one wafer, forming a peripheral circuit on another wafer, and laminating these wafers. When the semiconductor storage device is formed by such a method, for example, a part of a semiconductor substrate in the wafer on the memory cell array side may be used as a part of source lines.
When the semiconductor storage device is formed by such a method, at the time of formation of bonding pad electrodes, it may be necessary to form through via holes in, for example, the semiconductor substrate in the wafer on the memory cell array side to expose wirings in the wafer. When such a method is adopted, however, it is necessary to form through via holes having a large aspect ratio in the semiconductor substrate, which may cause an increase in manufacturing costs.
Accordingly, in at least one embodiment, the semiconductor substrate 100 is removed in the process described with reference to FIGS. 24 and 25 to expose the upper end of the semiconductor layer 120. Further, in the process after this, the conductive layer 150 connected to the upper end of the semiconductor layer 120 is formed. According to such a method, it is not necessary to form through via holes having a large aspect ratio at the time of formation of the bonding pad electrodes PX as described above. Accordingly, it is possible to prevent an increase in manufacturing costs.
Further, in at least one embodiment, in the process described with reference to FIGS. 26 and 27, a part of the insulating layer 102 and the insulating layer 125 is removed to form the structure in which the upper end of the semiconductor layer 120 is located above the upper surface of the insulating layer 102 and the upper end of the insulating layer 125. Further, in the process described with reference to FIG. 28, the conductive layer 150 is formed on the outer peripheral surface and the inner peripheral surface of the upper end portion of the semiconductor layer 120. According to such a method, it is possible to increase the contact area between the semiconductor layer 120 and the conductive layer 150 as compared with, for example, a case where the process illustrated in FIGS. 26 and 27 is not performed. Thus, it is possible to significantly prevent the contact resistance between the semiconductor layer 120 and the conductive layer 150.
Further, in at least one embodiment, in the process described with reference to FIG. 11, the conductive layer 111 in contact with the upper surface of the semiconductor substrate 100 is formed. Further, in the process described with reference to FIG. 16, the through via holes 120A are formed so as to expose the conductive layer 111 at the bottom surface of the through via holes 120A. According to such a method, charges accumulated on the inner peripheral surface of the through via holes 120A at the time of formation of the through via holes 120A may be discharged via the conductive layer 111. Thus, it is possible to suitably manufacture the semiconductor storage device by preventing arc discharge that may occur due to such charges and the destruction of the structure that may occur due to the arc discharge.
Second Embodiment
Next, a configuration of a semiconductor storage device according to a second embodiment will be described with reference to FIG. 29. FIG. 29 is a schematic cross-sectional view illustrating the configuration of the semiconductor storage device according to the second embodiment.
The semiconductor storage device according to the second embodiment is substantially configured in the same manner as the semiconductor storage device according to the first embodiment. The semiconductor storage device according to the second embodiment, however, includes a conductive layer 250 instead of the conductive layer 150.
The conductive layer 250 includes a plurality of conductors 251 formed corresponding to the semiconductor layers 120, a plurality of conductors 252 formed corresponding to the conductive layers 141, and a conductor 253 covering the surfaces of the plurality of conductors 251 and 252. The conductive layer 250 functions as, for example, a part of source lines.
The conductors 251 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). Further, the conductors 251 may contain, for example, polycrystalline silicon containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B). Each conductor 251 is bonded to the upper end, the outer peripheral surface, and the inner peripheral surface of the upper end portion of the semiconductor layer 120. Further, the conductor 251 is in contact with the upper end of the insulating layer 125.
The conductors 252 may contain, for example, the same material as the conductors 251. Each conductor 252 is in contact with the side surface in the X direction and the upper end of the upper end portion of the conductive layer 141, and extends in the X direction along the upper end of the conductive layer 141.
The conductor 253 may contain, for example, a stacked film of a barrier conductive film such as titanium nitride (TiN) and a metal film such as tungsten (W). Further, the conductor 253 may contain, for example, polycrystalline silicon containing an N-type impurity such as phosphorus (P) or a P-type impurity such as boron (B). The conductor 253 may include, for example, the same material as or a different material from the conductor 251. The conductor 253 covers, for example, the upper surface of the insulating layer 102, the upper surfaces of the conductors 251, and the upper surfaces of the conductors 252.
Furthermore, although not illustrated, the semiconductor storage device according to at least one embodiment includes a plurality of conductive layers having the same structure as the conductive layer 250, instead of the conductive layer 151 (FIG. 6), the conductive layer 152 (FIG. 9), and the conductive layer 153 (FIG. 9). These plurality of conductive layers function as wirings corresponding to the conductive layer 151 (FIG. 6), the conductive layer 152 (FIG. 9), and the conductive layer 153 (FIG. 9), respectively.
Next, a method of manufacturing the semiconductor storage device according to the second embodiment will be described with reference to FIGS. 30 and 31. FIGS. 30 and 31 are schematic cross-sectional views illustrating a method of manufacturing the semiconductor storage device according to the second embodiment.
The method of manufacturing the semiconductor storage device according to the present embodiment is substantially the same as the method of manufacturing the semiconductor storage device according to the first embodiment. In the present embodiment, however, for example, after the conductive layer 150A is formed in the process described with reference to FIG. 28, a portion of the conductive layer 150A formed on the upper surface of the insulating layer 102 is removed to form the plurality of conductors 251 and 252, for example, as illustrated in FIG. 30. This process is performed by, for example, a method such as RIE. Next, for example, as illustrated in FIG. 31, the conductor 253 is formed on the upper surface of the structure illustrated in FIG. 30. In this process, a conductive layer corresponding to the conductor 253 is formed by, for example, a method such as CVD, and the conductive layer is divided by a method such as RIE.
Third Embodiment
Next, a configuration of a semiconductor storage device according to a third embodiment will be described with reference to FIG. 32. FIG. 32 is a schematic cross-sectional view illustrating the configuration of the semiconductor storage device according to the third embodiment.
The semiconductor storage device according to the third embodiment is substantially configured in the same manner as the semiconductor storage device according to the first embodiment. The semiconductor storage device according to the third embodiment, however, includes an insulating layer 302 instead of the insulating layer 102.
The insulating layer 302 is substantially configured in the same manner as the insulating layer 102 according to the first embodiment.
However, as described with reference to FIG. 7, the insulating layer 102 includes the portion 1021 formed inside the memory cell array region RMCA and the portion 1020 formed outside the memory cell array region RMCA. Further, the thickness of the portion 1020 in the Z direction is smaller than the thickness of the portion 1021 in the Z direction. Further, the step 102S is formed at the connecting portion between the portion 1021 and the portion 1020.
Meanwhile, as illustrated in FIG. 32, the insulating layer 302 includes a portion 3021 formed inside the memory cell array region RMCA and a portion 3020 formed outside the memory cell array region RMCA. Further, the thickness of the portion 3020 in the Z direction is larger than the thickness of the portion 3021 in the Z direction. Further, a step 302S is formed at a connecting portion between the portion 3021 and the portion 3020. The step 302S is formed, for example, along the outer edge of the memory cell array region RMCA.
Furthermore, the semiconductor storage device according to at least one embodiment may include the conductive layer 250 instead of the conductive layer 150.
Next, a method of manufacturing the semiconductor storage device according to the third embodiment is described with reference to FIG. 33. FIG. 33 is a schematic cross-sectional view illustrating a method of manufacturing the semiconductor storage device according to the third embodiment.
The method of manufacturing the semiconductor storage device according to the present embodiment is substantially the same as the method of manufacturing the semiconductor storage device according to the first embodiment.
However, in the first embodiment, for example, in the process described with reference to FIG. 10, after forming the insulating layer 104 on the semiconductor substrate 100 of the wafer WM, the insulating layer 104 is removed in a region outside the memory cell array region RMCA (FIG. 2) by a method such as RIE or wet etching.
Meanwhile, in at least one embodiment, for example, as illustrated in FIG. 33, after forming the insulating layer 104 on the semiconductor substrate 100 of the wafer WM, the insulating layer 104 is removed in a region inside the memory cell array region RMCA (FIG. 2) other than a region outside the memory cell array region RMCA by a method such as RIE or wet etching.
Fourth Embodiment
Next, a method of manufacturing a semiconductor storage device according to a fourth embodiment will be described with reference to FIG. 34. FIG. 34 is a schematic cross-sectional view illustrating the method of manufacturing the semiconductor storage device according to the fourth embodiment.
The method of manufacturing the semiconductor storage device according to the present embodiment is substantially the same as the method of manufacturing the semiconductor storage device according to the first embodiment. However, in at least one embodiment, the processes described with reference to FIGS. 10 and 11 are not performed. Further, in at least one embodiment, a conductive layer 411 in contact with the upper surface of the semiconductor substrate 100 is formed on a dicing line DL of the semiconductor substrate 100 in the wafer WM. Further, an insulating layer 402 such as silicon oxide (SiO2) is formed in the other region.
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 disclosure. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.
Patent Application
20240422971
