Electrode Output Structure for Exstacking Architecture

Abstract

The present disclosure provides a method for fabricating a semiconductor device. The method can include bonding a first die and a second die face-to-face, where the first die includes a substrate, a transistor formed on a front side of the first die over a semiconductor layer with an insulating layer between the substrate and the semiconductor layer, and a first contact structure on the front side of the first die extending through the insulating layer. The method can also include exposing the first contact structure from a back side of the first die, forming a contact hole in the insulating layer to expose the semiconductor layer from the back side of the first die, and forming a first electrode output structure connected to the first contact structure on the back side of the first die and a second electrode output structure conductively connected to the semiconductor layer over the contact hole.

Description

[Technical field]

[0001] The present application describes embodiments that relate generally to semiconductor memory devices. [Background technology]

[0002] To achieve higher data packing density without requiring smaller memory cells, three-dimensional (3D) NAND flash memory technology has been developed. 3D NAND memory typically includes array transistors forming vertical memory cell columns and peripheral transistors forming peripheral circuitry. In conventional 3D NAND devices, the array transistors and peripheral transistors are fabricated on the same substrate. However, in the Xtacking architecture, an array substrate containing the array transistors and a peripheral substrate containing the peripheral transistors are stacked face-to-face via a bonding interface, with the transistors sandwiched between the two substrates. Thus, higher packing density, simpler process flow, and shorter cycle time can be achieved by the Xtacking architecture.

[0003] The ex-stacking architecture can also include an electrode output (pad-out) structure on the backside of either the array substrate or the peripheral substrate. Thus, an external circuit can provide control signals to the transistors sandwiched between the two substrates via the electrode output structure. The electrode output structure can be fabricated in a through silicon contact (TSC) configuration. Summary of the Invention [Means for solving the problem]

[0004] Aspects of the present disclosure provide an electrode output structure for a semiconductor device with an exstacking architecture and a method of forming the electrode output structure.

[0005] According to a first aspect, a semiconductor device with an exstacking architecture is disclosed that includes an electrode output structure. The semiconductor device can include a first die and a second die bonded face-to-face. The first die can include an insulating layer on a back side of the first die, a first contact structure extending from a front side of the first die through a first portion of the insulating layer, a semiconductor layer on a front side of a second portion of the insulating layer, and a first transistor formed on the front side of the semiconductor layer.

[0006] In some embodiments, the first transistor may include a memory cell formed across a semiconductor layer on a front side of the first die. The memory cell may include an alternating stack of word line layers and insulating layers, and a plurality of channel structures extending through the stack. In some embodiments, the first die may further include a plurality of contact structures formed in a staircase region of the stack, the plurality of contact structures being coupled to the word line layers. The staircase region may be on a boundary or in the middle of the stack. Additionally, the channel structure may include a channel layer surrounded by one or more insulating layers.

[0007] In some embodiments, the second die can include a substrate and peripheral circuitry for memory cells formed on the front side of the substrate.

[0008] The semiconductor device may also include a first electrode output structure disposed on a backside of the first die, the first electrode output structure being electrically coupled to the first contact structure. The semiconductor device may further include a second electrode output structure disposed on a backside of the first die, the second electrode output structure being electrically coupled to the semiconductor layer through a contact hole, the second electrode output structure filling the contact hole.

[0009] The first electrode output structure may include a first portion of the first conductive layer and the second electrode output structure may include a second portion of the first conductive layer. The first portion of the first conductive layer may be spaced apart from the second portion of the first conductive layer. The first conductive layer may be made of a first metallic material. In some embodiments, the first electrode output structure may further include a first portion of a second conductive layer disposed between the first contact structure and the first pad layer. The second electrode output structure may further include a second portion of a second conductive layer disposed between the semiconductor layer and the second pad layer. The first portion of the second conductive layer may be spaced apart from the second portion of the second conductive layer. The second conductive layer may be made of a second metallic material. In an example, the first metallic material is made of aluminum and the second metallic material is made of titanium.

[0010] In some embodiments, the first electrode output structure can be coupled to the input / output circuitry of the peripheral circuitry via the first contact structure, the bonding interface between the first die and the second die, and a corresponding second contact structure on the second die. The peripheral circuitry can be coupled to the memory cells via a corresponding third contact structure on the first die, the bonding interface, and a corresponding fourth contact structure on the second die. The second electrode output structure can be configured to provide an array common source to the memory cells.

[0011] In an alternative embodiment, the second die may further include a memory cell formed on the front side of the substrate, and the first transistor may include a peripheral circuit for the memory cell formed on the front side of the substrate. Furthermore, the first electrode output structure may be coupled to an input circuit / output circuit of the peripheral circuit via a first contact structure, and the peripheral circuit may be coupled to the memory cell via a corresponding contact structure in the first die, a bonding interface between the first die and the second die, and a corresponding contact structure in the second die.

[0012] According to a second aspect of the present disclosure, a method for fabricating a semiconductor device with an exstacking architecture having an electrode output structure is provided, which may include bonding a first die and a second die in a face-to-face relationship, the first die including a first substrate, an insulating layer on a front side of the first substrate, a first contact structure on a front side of the first die extending through a first portion of the insulating layer, and a semiconductor layer on a front side of a second portion of the insulating layer.

[0013] In some embodiments, the first die may further include memory cells formed on the front side of the semiconductor layer, and the second die may include peripheral circuits for the memory cells on the front side of the second substrate. In some embodiments, bonding the first die and the second die face-to-face may further include bonding a first bonding structure connected to the first contact structure in the first die to a second bonding structure connected to an input / output circuit of the peripheral circuit in the second die.

[0014] In an alternative embodiment, the second die may include memory cells disposed on a front side of the second die, and the first die may further include peripheral circuitry for the memory cells.

[0015] The method may also include exposing the first contact structure from the backside of the first die by removing the first substrate from the backside of the first die. In some embodiments, the method may include removing an etch stop layer after removing the first substrate, the etch stop layer being sandwiched between the first substrate and the insulating layer.

[0016] The method may further include forming a contact hole in a second portion of the insulating layer from a backside of the first die, the contact hole exposing the semiconductor layer, and forming a first electrode output structure conductively connected to the first contact structure on the backside of the first die and a second electrode output structure conductively connected to the semiconductor layer at the contact hole. In some embodiments, the second electrode output structure may be configured to provide an array common source to the memory cells.

[0017] Further, forming the first electrode output structure and the second electrode output structure may include forming a first conductive layer from a backside of the first die over the first contact structure and the semiconductor layer, and filling the contact holes with the first conductive layer and patterning the first conductive layer from the backside of the first die to form the first electrode output structure conductively connected to the first contact structure and the second electrode output structure conductively connected to the semiconductor layer. In some embodiments, the second conductive layer may be formed on the backside of the insulating layer, the second conductive layer connecting the first conductive layer to the first contact structure and connecting the first conductive layer to the semiconductor layer, and the second conductive layer is patterned using the same photomask as the first conductive layer.

[0018] In some embodiments, the first conductive layer can be made of a first metallic material and the second conductive layer can be made of a second metallic material, hi an example, the first conductive layer includes at least titanium and the second conductive layer includes at least aluminum.

[0019] Aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings, in which: It should be noted that, in accordance with the practice in the art, various features are not to scale, and in practice, the dimensions of various features may be increased or decreased for clarity of illustration. [Brief description of the drawings]

[0020] [Figure 1]1 is a cross-sectional view of a semiconductor device according to an exemplary embodiment of the present disclosure. [Diagram 2] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Diagram 3] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Figure 4] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Diagram 5] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Figure 6] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Figure 7] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Figure 8] 1A-1D are cross-sectional views of a semiconductor device at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. [Figure 9] 1 is a flow chart of an example process for manufacturing an example semiconductor device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Many different embodiments or examples are provided by the following disclosure to implement various features of the presented subject matter. To simplify the disclosure, specific examples of components and configurations are described below. These are, of course, merely examples and are not intended to be limiting. For example, forming a first feature over or on a second feature in the following description may include embodiments in which the first feature and the second feature are in direct contact, and may also include embodiments in which an additional feature is formed between the first feature and the second feature such that the first feature and the second feature cannot be in direct contact. Furthermore, the present disclosure may repeat reference numbers and / or character strings in various examples. This repetition is for simplicity and clarity and does not, in itself, dictate a relationship between the various embodiments and / or configurations described.

[0022] Additionally, spatially relative terms such as "below," "down," "lower," "above," "upper," and the like may be used herein for ease of description to describe the relationship of one element to another, or the relationship of one feature to another, as shown in the figures. The spatially relative terms are intended to encompass various orientations of the device during use or operation in addition to the orientation shown in the figures. The device may be oriented in other configurations (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0023] The present disclosure provides a method for forming an electrode output structure for a 3D memory device with an ex-stacking architecture. The method can include bonding a first die and a second die, removing a substrate of the first die, forming a contact hole, and forming an electrode output structure. Compared with through silicon contact (TSC) electrodes for the ex-stacking architecture, the disclosed method eliminates the additionally required deposition of a dielectric layer and etching of TSC metal, thus simplifying the manufacturing process.

[0024] 1 is a cross-sectional view of a semiconductor device 100 according to an exemplary embodiment of the present disclosure. As shown, the device 100 may include a first die D1 and a second die D2 bonded together in a face-to-face manner (circuit side is top and substrate side is bottom) via a bonding interface 140. The first die D1 and the second die D2 may include bonding structures 141 and 142, respectively, that are correspondingly aligned with each other. Furthermore, the bonding structure 141 may be electrically coupled to the corresponding bonding structure 142.

[0025] As shown in FIG. 1, the first die D1 may include an insulating layer 103 (e.g., silicon oxide), a semiconductor layer 105 (e.g., doped polysilicon) on the front side of the insulating layer 103, and a first contact structure 121 (e.g., tungsten) formed on the front side of the insulating layer 103 and extending through the insulating layer 103.

[0026] The first die D1 may also include a 3D NAND memory cell. For example, an alternating stack of insulating layers 111 and word line layers 112 (also referred to as gate layers) may be disposed on the front side of the semiconductor layer 105. The stack may include an array region 110 in which at least one channel structure 130 is formed and extends through the stack into the semiconductor layer 105. The stack of insulating layers 111 and word line layers 112 and the channel structure 130 may form a stack of transistors, such as an array of vertical memory cell strings. In some examples, the stack of transistors may include memory cells and select transistors, such as one or more bottom select transistors and one or more top select transistors. In some examples, the stack of transistors may also include one or more dummy select transistors.

[0027] The insulating layer 111 may be made of an insulating material such as silicon nitride or silicon oxide. The word line layer 112 may be made of a gate stack material such as a high-k gate insulator layer and a metal gate electrode. The channel structure 130 may include a channel layer 131 (e.g., polysilicon) surrounded by one or more insulating layers 132, such as a tunneling layer (e.g., silicon oxide), a charge trapping layer (e.g., silicon nitride), and a barrier layer (e.g., silicon oxide), which together form an oxide-nitride-oxide structure surrounding the channel layer 131.

[0028] Additionally, the stack can have a staircase region 120 with a plurality of second contact structures 122 and third contact structures 123 formed therein. The second contact structures 122 are connected to a word line layer 112, which can function as gates and dummy gates for vertical memory cell columns. The third contact structures 123 are connected to the semiconductor layer 105. It should be noted that the device 100 can have various staircase configurations, such as a center staircase mounting configuration and a side staircase mounting configuration.

[0029] 1, the first die D1 may further include a first conductive layer 171 (also referred to as a pad layer) on a back side of the second conductive layer 161 (also referred to as a liner layer), the first conductive layer 171 having a first portion 161a covering the back side of the first contact structure 121 and a second portion 161b covering the hole of the insulating layer 103. The first conductive layer first portion 171a and the first conductive layer second portion 171b may be disposed on the back side of the second conductive layer first portion 161a and the back side of the second conductive layer second portion 161b, respectively, to form a first electrode output structure and a second electrode output structure. The first conductive layer first portion 171a may be electrically coupled to the first contact structure 121, and the first conductive layer second portion 171b may be electrically coupled to the semiconductor layer 105. In this example, the first conductive layer 171 is aluminum, and the semiconductor layer 105 is polysilicon. The second conductive layer 161 can be a bonding layer, such as a titanium layer having a thickness in the range of 10 nm to 20 nm, disposed between aluminum and polysilicon. In some embodiments, the second conductive layer 161 can be formed from titanium silicide at relatively high temperatures (e.g., above 500° C.). In other examples, the first conductive layer 171 can be made of other conductive materials and the second conductive layer 161 can be a barrier layer, a seed layer and / or a bonding layer. The second conductive layer 161 can also be used to reduce contact resistance. In some embodiments, the second conductive layer 161 may not be necessary.

[0030] In the example of FIG. 1, the first die D1 can include 3D memory cells, and the second die D2 can include peripheral circuits (e.g., address decoders, driving circuits, sense amplifiers, etc.). In general, the peripheral circuits of the second die D2 can be coupled to the memory cells using external circuits. For example, the peripheral circuits receive instructions from the external circuits via the first electrode output structures (171a and 161a), provide control signals to the memory cells, receive data from the memory cells, and output data to the external circuits via the first electrode output structures (171a and 161a). Furthermore, in some embodiments, the semiconductor layer 105 is coupled to an array common source (ACS) for the memory cell array, so that the second electrode output structures (171b and 161b) can provide an input / output electrode output structure to the ACS.

[0031] For simplicity, the second die D2 is shown with a substrate 191 and two transistors 180 formed on the substrate. For example, the transistors 180 may form a complementary metal oxide semiconductor (CMOS). The substrate 191 may be any suitable substrate, such as a silicon (Si) substrate, a germanium (Ge) substrate, a silicon-germanium (SiGe) substrate, and / or a silicon-on-insulator (SOI) substrate. The substrate may include a semiconductor material, such as a group IV semiconductor, a group III-V compound semiconductor, or a group II-VI oxide semiconductor. The group IV semiconductor may include Si, Ge, or SiGe. The substrate 191 may be a bulk wafer or an epitaxial layer. It is noted that the first die D1 initially includes a substrate on which the semiconductor layer 105 and the insulating layer 103 are disposed. The substrate is removed before forming the electrode output structures (171 and 161).

[0032] In some embodiments, the semiconductor memory device may include multiple array dies (e.g., a first die D1) and a CMOS die (e.g., a second die D2). The multiple array dies and the CMOS die may be stacked and bonded together. Each array die is coupled to a portion of the CMOS die, and the CMOS die may drive the array dies individually or together in a similar manner. Furthermore, in some examples, the semiconductor device 100 includes at least a first wafer and a second wafer bonded face-to-face. The first die D1 is arranged on the first wafer with other array dies such as D1, and the second die D2 is arranged on the second wafer with other CMOS dies such as D2. The first wafer and the second wafer are bonded together, such that the array dies on the first wafer are bonded to the corresponding CMOS dies on the second wafer.

[0033] In an alternative embodiment, the first die D1 may include peripheral circuits, and the second die D2 may include 3D memory cells (not shown). Nevertheless, the electrode output structures (171 and 161) may be disposed on the back side of the first die D1. Because the input / output signals do not need to go through the memory cell array die, the paths of the input / output signals may be shorter than the signal paths in FIG. 1.

[0034] 2-9 are cross-sectional views of a semiconductor device, such as device 100, at various intermediate stages in its manufacture, according to exemplary embodiments of the present disclosure. Device 100 may be any suitable device, such as, for example, a memory circuit, a semiconductor chip (or die) with a memory circuit formed on the semiconductor chip, a semiconductor wafer with multiple semiconductor dies formed on the semiconductor wafer, a stack of semiconductor chips, a semiconductor package including one or more semiconductor chips assembled on a package substrate, etc.

[0035] 2 shows a cross-sectional view of a semiconductor device 200 that will eventually become the device 100. It should be understood that FIG. 2 shows only a portion of the device 200. Similar to the device 100, the device 200 may include a first die D1′ corresponding to the first die D1, a second die (not shown) corresponding to the second die D2, bonded together via a bonding interface (not shown) corresponding to the bonding interface 140. For simplicity, the bonding structure 141 and the cap layer 106 of the first die D1 in FIG. 1 are omitted in FIG. 2.

[0036] As shown, device 200 can include a substrate 201 (e.g., silicon) on a backside of first die D1′, and an etch stop layer 202 (e.g., silicon nitride) on a frontside of substrate 201. Device 200 can also include an insulating layer 203 (e.g., silicon oxide) on a frontside of etch stop layer 202, which ultimately becomes insulating layer 103 in FIG. 1. In some embodiments, etch stop layer 202 may not be required.

[0037] As shown in Figure 2, device 200 has components configured similarly to corresponding components of device 100 in Figure 1. For example, first contact structure 221, semiconductor layer 205, alternating stacks of insulating layer 211 and word line layer 212, array region 210, staircase region 220, channel structure 230, plurality of second contact structures 222, and third contact structure 223 are configured similarly to first contact structure 121, semiconductor layer 105, alternating stacks of insulating layer 111 and word line layer 112, array region 110, staircase region 120, channel structure 130, plurality of second contact structures 122, and third contact structure 123, respectively. These components have been described above but will not be repeated here for purposes of clarity.

[0038] Figure 3 shows device 200 after substrate 201 has been removed from the backside in Figure 2. Removal of substrate 201 can be accomplished by chemical mechanical polishing (CMP) and / or wet etching. An etch stop layer 202 can be used to determine when to stop the CMP and / or wet etching process.

[0039] FIG. 4 shows the device 200 after the etch stop layer 202 and a portion of the first contact structure 221 have been removed in FIG. 3. Thus, the remaining first contact structure 221 and the insulating layer 203 are exposed from the back side. As in FIG. 3, the removal of the etch stop layer 202 and the portion of the first contact structure 221 can be achieved by a CMP process. Alternatively, the etch stop layer 202 can be removed by a first etching process, and the portion of the first contact structure 221 can be removed by a second etching process. In some embodiments, the removal of the portion of the first contact structure 221 may not be necessary. As a result, the portion of the first contact structure 221 is exposed (not shown). Furthermore, while the first contact structure 221 is shown as extending into the etch stop layer 202, in some embodiments it only extends to the back side surface 203′ of the insulating layer 203 (not shown). Therefore, removal of any portion of the first contact structure 221 may not be necessary.

[0040] In FIG. 5, contact holes 251 can be formed in the insulating layer 203 of the device 200, such that a portion of the semiconductor layer 205 is exposed. The contact holes 251 can have a bottom 251′ and two sidewalls 251″. In the example of FIG. 5, two contact holes 251 are shown having a trapezoidal cross section extending from the front side to the back side. It will be understood that any number of contact holes 251 can be formed and that the contact holes 251 can have other shapes, such as a rectangle. The contact holes 251 can be formed by an etching process using a photoresist as an etching mask defined by a photolithography process.

[0041] In FIG. 6, a second conductive layer 261, which will eventually become the second conductive layer 161 in FIG. 1, can be formed to conformally coat the exposed first contact structure 221, the insulating layer 203, and the exposed portions of the semiconductor layer 205. As a result, the second conductive layer 261 covers the bottom 251' and the sidewalls 251" of the contact hole 251. The second conductive layer 261 can be made of titanium and can be formed by chemical vapor deposition. The second conductive layer 261 can have a thickness in the range of 10 nm to 20 nm. In some embodiments, the second conductive layer 261 may not be needed, and therefore this step can be omitted.

[0042] In FIG. 7, a first conductive layer 271, which will eventually become the first conductive layer 171 in FIG. 1, can be formed from the back side to the second conductive layer 261, so that the contact hole 251 can be filled with the first conductive layer 271. The first conductive layer 271 can be a conductive layer made of aluminum and can be formed by chemical vapor deposition. In an example where the second conductive layer 261 is titanium and the semiconductor layer 205 is polysilicon, the titanium can be a bonding layer between the aluminum and the polysilicon. Furthermore, a recess structure 272 can be formed on the back side of the first conductive layer 271 as a result of the contact hole 251.

[0043] FIG. 8 shows the device 200 after a portion of the first conductive layer 271 and a portion of the second conductive layer 261 have been removed in FIG. 7. The removal of the portion of the first conductive layer 271 and the portion of the second conductive layer 261 can be achieved by etching using a photoresist and / or a hard mask layer. Thus, the first portion 271a of the first conductive layer can be disposed on the first portion 261a of the second conductive layer to form a first electrode output structure, and the second portion 271b of the first conductive layer can be disposed on the second portion 261b of the second conductive layer to form a second electrode output structure. Similar to the device 100, an external circuit (not shown) can provide control signals to and receive data from the peripheral circuit (not shown) of the second die D2′ of the device 200 via the first electrode output structure (271a and 261a) that is coupled to the peripheral circuit via the first contact structure 221. The peripheral circuitry can then interact with the transistors of the first die D1'.

[0044] 9 is a flow chart of an example process 900 for fabricating an example semiconductor device, such as device 100 in FIG. 1 or device 200 in FIG. 8, according to an embodiment of the present disclosure. Process 900 begins at step S901 where a first die and a second die are bonded face-to-face (circuit side is top and substrate side is bottom). The first die can include a first substrate, a first transistor formed on the front side of the first die in a semiconductor layer with an insulating layer between the first substrate and the semiconductor layer, and a first contact structure on the front side of the first die that extends through the insulating layer. The second die can include a second substrate with a structure formed on the front side of the second die.

[0045] To bond the first die to the second die, a plurality of first bonding structures, such as support posts, can be formed on the front side of the first die, and a plurality of second bonding structures can be formed on the front side of the second die. The bonding structures can include Cu, Ni, and SnAg. The bonding process can be operated at a temperature above 220° C. such that the bonding structures melt, so that the first bonding structures can form a connection with the corresponding second bonding structures. Thus, the first transistor in the first die can be coupled to the structure in the second die through the corresponding bonding structures at the bonding interface and the corresponding contact structures in the two dies.

[0046] Further, as shown in the example of Figure 1, the first transistors can form a vertical column of memory cells and the second die can include the peripheral circuitry. In an alternative embodiment, the first transistors can include the peripheral circuitry and the second die can include the memory cells.

[0047] In step S902, the first substrate is removed from the back side of the first die to expose the first contact structure from the back side of the first die. As a result, the insulating layer is also exposed from the back side of the first die. In an example where an etch stop layer is sandwiched between the first substrate and the insulating layer, the etch stop layer can also be removed from the back side of the first die. Removal of the first substrate and the etch stop layer can be accomplished by CMP and / or etching.

[0048] In step S903, a contact hole exposing a portion of the semiconductor layer is formed in the insulating layer from the back side of the first die. The contact hole has a bottom and two sidewalls. Photolithography techniques can be used to define a contact hole pattern in the photoresist and / or hard mask layer, etching techniques can be used to transfer the pattern to the insulating layer, and then the photoresist and / or hard mask layer can be removed.

[0049] In step S904, the first electrode output structure and the second electrode output structure can be formed on the back side of the first die by two deposition steps, a photolithography step, and two etching steps. First, a conformal liner layer can be formed by a first deposition step, such that the conformal liner layer covers the exposed first contact structure, the insulating layer, and the exposed portion of the semiconductor layer. The liner layer can also cover the bottom and sidewall of the contact hole. Then, a pad layer can be formed from the back side over the liner layer by a second deposition step. The pad layer can fill the contact hole, and as a result of this contact hole, a recess structure can be formed on the back side. After that, a photolithography step can be performed to define the electrode output pattern from a photoresist and / or hard mask layer that serves as an etching mask. Then, two etching steps can be performed to transfer the electrode output pattern to the pad layer and the liner layer, thereby forming the first electrode output structure and the second electrode output structure. In some embodiments, the two etching steps can be replaced by a single etching step. Additionally, the photoresist and / or hardmask layer will be removed.

[0050] As a result, the first electrode output structure is conductively connected to the first contact structure with the first portion of the liner layer sandwiched therebetween. An external circuit can be coupled to peripheral circuitry of the device via the first electrode output structure and the first contact structure. Similarly, a second electrode output structure is formed over the contact hole and conductively connected to the semiconductor layer with the second portion of the liner layer sandwiched therebetween. The second electrode output structure can be configured to provide an array common source to the memory cell.

[0051] Further, in examples where the electrode output structure is aluminum and the semiconductor layer is polysilicon, the liner layer can be made of a bonding material such as titanium. In other examples, the electrode output structure can be made of other conductive materials and the liner layer can be a barrier layer, a seed layer, and / or a bonding layer. The liner layer can also be used to reduce contact resistance. In some embodiments, a liner layer may not be required.

[0052] It should be noted that additional steps can be provided during and before the process 900, and some of the described steps can be replaced, eliminated, or performed in a different order for additional embodiments of the process 900. For example, the formation of a liner layer may not be necessary. In particular, in the step S904, the pad layer having the recessed structure can be planarized by a CMP step before the photolithography step of defining the etching mask. Thus, the electrode output structure has a flat surface on the back side. In addition, the electrode output structure can also be formed using a lift-off method in which a photolithography step is performed before depositing the liner layer and the pad layer.

[0053] The various embodiments described herein provide several advantages. For example, in related 3D NAND memory devices, electrode output structures are formed in a TSC configuration that requires deposition and etching of an interlayer dielectric (e.g., silicon oxide, silicon nitride, etc.) and a TSC metal (e.g., tungsten) on the backside of the first substrate. The disclosed method simplifies the manufacturing process and allows for the formation of non-TSC electrode output structures.

[0054] The above description outlines the features of some embodiments, so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art will appreciate that the present disclosure can be easily used as a basis for designing or modifying other processes and structures to accomplish the same purposes and / or achieve the same advantages of the embodiments introduced herein. Those skilled in the art will also recognize that such equivalent structures do not depart from the spirit and scope of the present disclosure, and that various modifications, substitutions, and alterations can be made herein without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0055] 100 Semiconductor Devices 103 Insulating layer 105 Semiconductor layer 106 Cap Layer 110 Array Area 111 Insulating layer 112 Word Line Layer 120 Stairs area 121 First contact structure 122 Second Contact Structure 123 Third Contact Structure 130 Channel Structure 131 Channel Layer 132 Insulating Layer 140 Joint interface 141 Joint structure 142 Joint structure 161 Second conductive layer, electrode output structure 161a: first portion of second conductive layer, first electrode output structure 161b: second portion of second conductive layer, second electrode output structure 171 First conductive layer, electrode output structure 171a: first portion of first conductive layer, first electrode output structure 171b: second portion of first conductive layer, second electrode output structure 180 Transistors 191 Substrate 200 Semiconductor Devices 201 Substrate 202 Etch stop layer 203 Insulating layer 203' Back surface of insulating layer 203 205 Semiconductor layer 210 Array Region 211 Insulating layer 212 Word Line Layer 220 Stairs area 221 First contact structure 222 Second Contact Structure 223 Third Contact Structure 230 Channel Structure 251 Contact Hole 251' Bottom of contact hole 251” Contact hole sidewall 261 Second conductive layer 261a: first portion of second conductive layer 261b: second portion of the second conductive layer 271 First conductive layer 271a: first portion of first conductive layer 271b second portion of first conductive layer 272 Recessed structure D1 First Die D1' First die D2 Second Die D2' Second die

Claims

1. 1. A method of fabricating a semiconductor device, comprising: bonding a first die and a second die in a face-to-face relationship, the first die including a first substrate, an insulating layer on a front side of the first substrate, a first contact structure on a front side of the first die extending through a first portion of the insulating layer, and a semiconductor layer on a front side of a second portion of the insulating layer; removing the first substrate from a backside of the first die to expose the first contact structure from the backside of the first die; forming a contact hole in the second portion of the insulating layer from the back side of the first die, the contact hole exposing the semiconductor layer; forming a first electrode output structure on the back side of the first die, the first electrode output structure being conductively connected to the first contact structure and a second electrode output structure being conductively connected to the semiconductor layer through the contact hole; A method for fabricating a semiconductor device, comprising:

2. forming the first electrode output structure and the second electrode output structure, forming a first conductive layer from the back side of the first die over the first contact structure and the semiconductor layer, the first conductive layer filling the contact hole; patterning the conductive layer from the backside of the first die to form the first electrode output structure conductively connected to the first contact structure and the second electrode output structure conductively connected to the semiconductor layer; The method of claim 1 further comprising:

3. forming the first electrode output structure and the second electrode output structure, forming a second conductive layer on a back side of the insulating layer, the second conductive layer connecting the first conductive layer to the first contact structure and connecting the first conductive layer to the semiconductor layer; patterning the second conductive layer using the same photomask as the first conductive layer; The method of claim 2 , further comprising:

4. the first conductive layer is made of a first metallic material; The method of claim 3 , wherein the second conductive layer is made of a second metallic material.

5. the first conductive layer includes at least aluminum; The method of claim 4 , wherein the second conductive layer comprises at least titanium.

6. exposing the first contact structure from the back side of the first die, removing an etch stop layer after removing the first substrate, the etch stop layer being sandwiched between the first substrate and the insulating layer; The method of claim 1 further comprising:

7. the first die further includes a memory cell formed on a front side of the semiconductor layer; the second die includes peripheral circuits for the memory cells on a front side of a second substrate; The method of claim 1.

8. The step of bonding the first die and the second die in a face-to-face relationship includes:

8. The method of claim 7, further comprising the step of bonding a first bonding structure connected to the first contact structure in the first die to a second bonding structure connected to an input circuit / output circuit in the peripheral circuit in the second die.

9. The method of claim 7 , wherein the second electrode output structure is configured to provide an array common source to the memory cell.

10. the second die includes memory cells disposed on a front side of the second die; The method of claim 1 , wherein the first die further includes peripheral circuitry for the memory cells.

11. a first die and a second die bonded face to face, the first die including an insulating layer on a back surface side of the first die, a first contact structure extending from a front surface side of the first die through a first portion of the insulating layer, a semiconductor layer on a front surface side of a second portion of the insulating layer, and a first transistor formed on the front surface side of the semiconductor layer, a portion of the insulating layer being disposed between the first contact structure and the semiconductor layer, the portion of the insulating layer being in contact with the first contact structure and a side of the semiconductor layer facing the first contact structure; a first electrode output structure disposed on the back side of the first die, the first electrode output structure being electrically coupled to the first contact structure; a second electrode output structure disposed on the back side of the first die, the second electrode output structure being electrically coupled to the semiconductor layer; 13. A semiconductor device comprising:

12. the first transistor includes a memory cell formed across a semiconductor layer on the front side of the first die; The semiconductor device of claim 11 , wherein the second die includes a substrate and peripheral circuitry for the memory cells formed on a front side of the substrate.

13. The memory cell comprises: an alternating laminate of word line layers and insulating layers; a plurality of channel structures extending through the stack, the channel structures including a channel layer surrounded by one or more insulating layers; The semiconductor device of claim 12 , comprising:

14. 14. The semiconductor device of claim 13, wherein the first die further comprises a plurality of contact structures formed in a staircase region of the stack, the plurality of contact structures being coupled to the word line layer, the staircase region being on a boundary or in the middle of the stack.

15. the first electrode output structure is coupled to an input circuit / output circuit of the peripheral circuit via the first contact structure, a bonding interface between the first die and the second die, and a corresponding second contact structure on the second die; 13. The semiconductor device of claim 12, wherein the peripheral circuitry is coupled to the memory cells via corresponding third contact structures in the first die, the bonding interface, and corresponding fourth contact structures in the second die.

16. The semiconductor device of claim 12 , wherein the second electrode output structure is configured to provide an array common source to the memory cell.

17. the second die further includes a memory cell formed on a front side of the substrate; the first transistor includes a peripheral circuit for the memory cell formed on a front surface side of the substrate; the first electrode output structure is coupled to an input circuit / output circuit of the peripheral circuit via the first contact structure; 13. The semiconductor device of claim 12, wherein the peripheral circuits are coupled to the memory cells via corresponding contact structures in the first die, a bonding interface between the first die and the second die, and corresponding contact structures in the second die.

18. The method of claim 17, wherein the first electrode output structure includes a first portion of a first conductive layer; the second electrode output structure includes a second portion of the first conductive layer; the first portion of the first conductive layer is spaced from the second portion of the first conductive layer; The semiconductor device of claim 11 , wherein the first conductive layer is made of a first metallic material.

19. the first electrode output structure further includes a first portion of a second conductive layer disposed between the first contact structure and the first conductive layer; the second electrode output structure further includes a second portion of the second conductive layer disposed between the semiconductor layer and the first conductive layer; the first portion of the second conductive layer is spaced from the second portion of the second conductive layer; 20. The semiconductor device of claim 18, wherein the second conductive layer is made of a second metallic material.

20. the first metallic material is made of aluminum; 20. The semiconductor device of claim 19, wherein the second metallic material is made of titanium.

Images