TWI595601B - Memory device and method for fabricating the same - Google Patents

Description

Memory element and manufacturing method thereof

The present disclosure relates to a semiconductor device and a method of fabricating the same, and more particularly to a memory device and a method of fabricating the same.

Non-volatile memory components, such as flash memory, have the property of not losing information stored in the memory unit when the power source is removed. It has been widely used in solid-state mass storage applications for portable music players, mobile phones, digital cameras, and the like. In order to meet the demand for higher density storage capacity, there are various three-dimensional memory components of different structures, such as single-gate memory cells, double gate memory cells, and wraparound gates. A three-dimensional flash memory component of a surrounding cell is proposed.

Three-dimensional memory components, such as vertical-channel (VC) three-dimensional NAND flash memory components, have many layer stack (memory layer) structures for higher storage capacity and superior electronic characteristics, such as Has good data preservation reliability and operating speed. However, as the component size continues to shrink, the RC delay caused by the resistance and capacitance of the wire, such as the word line or source line, will become a three-dimensional memory. One of the main factors in the operation speed of body component erasing and programming. At present, the industry uses a lower resistance metal as the gate of the vertical channel type three-dimensional NAND flash memory device to reduce the time delay of the word line.

However, the metal gate fabrication process of the vertical channel type three-dimensional NAND memory device must first form an etched trench through the multilayer stack structure, and then etch another trench to remove the sacrifice in the layer stack structure. The layer can only fill the metal gate (word line). The arrangement of the etched trenches will occupy the formation space of the memory cells and affect the storage capacity of the components. In addition, the sacrificial layer is easily left in the multi-layer stack structure, or the memory layer is damaged due to over-etching, which causes memory cell defects, which seriously affects the storage capacity and process yield of the vertical channel type three-dimensional NAND flash memory device.

Therefore, there is a need to provide a more advanced memory component and method of making the same to improve the problems faced by conventional techniques.

An embodiment of the present specification is to provide a memory component. The memory component includes a plurality of germanium-containing conductive layers, a plurality of series selection lines, a plurality of strings, a plurality of bit lines, a complex array multi-layer plug structure, and a plurality Metal strapped word line. Wherein, the germanium-containing conductive layers are vertically stacked on the substrate in parallel with each other. The string selection line is located above the germanium containing conductive layer and extends in the first direction. The string is perpendicular to the germanium-containing conductive layer and the string select line, and is electrically connected to the tandem select line. The bit lines are located above the string selection line and extend in the second direction and are electrically connected to the series respectively. The multi-layer plug structures are arranged in the first direction, and the plurality of strings are respectively sandwiched between the adjacent two multi-layer plug structures. Each of the multi-layer plug structures includes a plurality of via plugs, and each of the via plugs is electrically connected to a germanium-containing conductive layer. The metal word lines extend in a first direction, and each of the metal word lines is electrically connected to a via plug that conducts the same germanium-containing conductive layer.

Another embodiment of the present specification is to provide a method of fabricating a memory device. The method includes the steps of first forming a plurality of germanium-containing conductive layers vertically stacked and parallel to each other on a substrate. Thereafter, a plurality of strings are formed to vertically penetrate the conductive layer containing germanium. And forming a plurality of string selection lines on the germanium conductive layer, and extending the string selection lines in the first direction, and electrically connecting the series. Next, a multi-array multi-layer plug structure is formed, arranged in the first direction, and the plurality of strings are respectively sandwiched between the adjacent two multi-layer plug structures. Each of the multi-layer plug structures includes a plurality of via plugs, and each of the via plugs is electrically connected to a germanium-containing conductive layer. Subsequently, a plurality of bit lines are formed above the serial selection line, so that the bit lines extend in the second direction and are electrically connected to the series. And forming a plurality of metal word lines above the multi-layer plug structure, extending in the first direction, and electrically connecting each of the metal word lines to the same germanium-containing conductive plug.

According to the above embodiment, the present invention provides a memory element and a method of fabricating the same. The multi-layer plug structure in which the multiple arrays are arranged in parallel along the tandem selection line in the multi-layer stack structure of the three-dimensional memory element, and the plurality of strings formed in the multi-layer stack structure are respectively sandwiched between two adjacent ones. Between the multi-layer plug structures, and each of the interposer plugs included in the multi-layer plug structure, respectively A germanium-containing conductive layer in the stacked structure is electrically connected. And electrically connecting a plurality of via plugs that are connected to the same conductive layer containing germanium by metal word lines. The overall resistivity of the gate layer in the three-dimensional memory device is reduced by the connection of the multi-layer plug structure and the metal word line to reduce the signal transmission delay caused by the gate resistance and the capacitance. Moreover, since the three-dimensional memory component uses a germanium-containing conductive material as a gate, it is not necessary to form a metal gate, which can enlarge the bandwidth of the string selection line, and solve the conventional technique because of the storage capacity caused by the metal gate process. And the problem that the process yield cannot be improved.

10‧‧‧Multilayer stacking structure

100‧‧‧Vertical channel type three-dimensional NAND flash memory components

101‧‧‧Substrate

102, 112, 122, 132 and 142‧‧ ‧ conductive layers

103‧‧‧Insulation

104‧‧‧Listing

104a‧‧‧ memory layer

104b‧‧‧channel layer

105‧‧‧ openings

106‧‧‧Sequence selection line

107‧‧‧Source contact structure

107a‧‧‧Dielectric material layer

107b‧‧‧Electrical materials

108‧‧‧ openings

109‧‧‧hard mask layer

110‧‧‧Multilayer plug structure

110a, 110b, 110c and 110d‧‧‧ interlayer plugs

113‧‧‧Serial wire

114‧‧‧Contact plug

115‧‧‧ source

116‧‧‧ bit line

117a, 117b, 117c and 117d‧‧‧ metal word lines

118‧‧‧ source line

119‧‧‧ Guide hole

200‧‧‧Three-dimensional memory components

301‧‧‧ Grounding layer

303‧‧‧Insulation

A‧‧‧ area

D1‧‧‧ Distance between two adjacent multi-layer plug structures

D2‧‧‧ Distance between two adjacent source contact structures

S1, S2, S3 and S4‧‧‧ tangent

The above-described embodiments and other objects, features and advantages of the present invention will become more apparent from the embodiments of the invention. The embodiment shows a perspective view of a partial structure of a multilayer stack structure formed on a substrate; FIG. 1B is a perspective view showing a partial structure after forming a plurality of strings on the structure of FIG. 1A; FIG. 1C is based on the 1st B Figure 1 is a top view of the structure after forming a plurality of lines on the structure of the first B to form a plurality of series of line selection lines; Figure 1E is based on Figure 1D Structural view; FIG. 1F is a partial perspective view showing a complex array of multi-layer plug structures and contact plugs formed on the structure of FIG. 1D; FIG. 1G is a structure according to FIG. View; 1H diagram shows the formation of a plurality of source lines and bits on the structure of the 1G diagram A top view of the structure after the line; FIG. 1I is a top view of the structure after forming a plurality of metal word lines on the structure of FIG. 1H; FIGS. 2A to 2D are drawn according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a portion of a plurality of plug structures according to another embodiment of the present invention; FIG. 4A is a cross-sectional view taken along line 1H. A cross-sectional view of a portion of the structure shown in the tangential line S1; a cross-sectional view of a portion of the structure taken along line S2 shown in FIG. 1H; and a fifth embodiment of the present invention in accordance with another embodiment of the present invention. A schematic cross-sectional view of a portion of the ground layer, the source contact structure, and the source line; FIG. 6A is a cross-sectional view of a portion of the structure taken along line S3 of FIG. 1I; FIG. 1 is a partial structural sectional view showing a tangential line S4 shown in FIG. 1; and FIG. 7 is a partial structural top view of a vertical channel type three-dimensional NAND memory element according to another embodiment of the present invention.

The invention provides a memory component and a manufacturing method thereof, which can reduce the overall resistivity of the memory component to reduce the signal transmission delay caused by the resistance and the capacitance. In order to more clearly understand the above-described embodiments and other objects, features and advantages of the present invention, the following is a vertical channel type three-dimensional NAND flash memory element. The member 100 is a preferred embodiment and will be described in detail in conjunction with the drawings.

However, it must be noted that these specific embodiments and methods are not intended to limit the invention. The invention may be practiced with other features, elements, methods and parameters. The preferred embodiments are merely illustrative of the technical features of the present invention and are not intended to limit the scope of the invention. Equivalent modifications and variations will be made without departing from the spirit and scope of the invention. In the different embodiments and the drawings, the same elements will be denoted by the same reference numerals.

The method of fabricating the vertical channel type three-dimensional NAND flash memory device 100 includes the steps of first forming a multilayer stack structure 10 on the substrate 101. Referring to FIG. 1A, FIG. 1A is a partial perspective view showing a multilayer stacked structure 10 formed on a substrate 101 according to an embodiment of the present invention. In the present embodiment, the multilayer stack structure 10 includes a plurality of germanium-containing conductive layers 102, 112, 122, 132, and 142 and a plurality of insulating layers 103. The germanium-containing conductive layers 102, 112, 122, 132, and 142 and the plurality of insulating layers 103 are alternately stacked in parallel along the Z-axis direction.

In some embodiments of the present invention, the germanium-containing conductive layers 102, 112, 122, 132, and 142 are preferably made of a polysilicon material; the insulating layer 103 is preferably made of a silicon oxide material. Although the multilayer stacked structure 10 illustrated in FIG. 1A includes only five layers of germanium-containing conductive layers 102, 112, 122, 132, and 142 and four insulating layers 103. However, it is merely an example. In other embodiments, the number of the conductive layer containing the tantalum and the insulating layer is not limited thereto.

Thereafter, a plurality of strings 104 are formed to vertically penetrate the germanium-containing conductive layers 102, 112, 122, 132, and 142 and the insulating layer 103. Referring to FIG. 1B and FIG. 1C, FIG. 1B is a partial perspective view showing a plurality of strings 104 formed on the structure of FIG. 1A. Figure 1C is a top view of the structure according to Figure 1B.

In an embodiment of the invention, each of the strings 104 includes a memory layer 104a and a channel layer 104b. The memory layer 104a may be a NON structure composed of a silicon nitride layer, a hafnium oxide layer, and a tantalum nitride layer. The channel layer 104b is preferably a polysilicon material. By interleaving the series 104 and the germanium-containing conductive layers 102, 112, 122, 132, and 142, a plurality of cells arranged in a plurality of columns and a plurality of columns can be defined.

E.g. In some embodiments of the invention, the memory cells may be arranged in a matrix array. In other embodiments of the present invention, the arrangement of the memory cells may also be a honeycomb array. It should be noted, however, that the embodiments of the present invention are not limited to the arrangement of the two types of memory cells, and any design rules applicable to the three-dimensional memory elements are not departing from the spirit of the present invention.

Please refer to FIG. 2A to FIG. 2D . FIG. 2A to FIG. 2D are schematic cross-sectional views showing a part of the process structure for forming the series 104 according to an embodiment of the invention. The formation of the string 104 may include the steps of first forming a plurality of openings 105 in the multilayer stack structure 10 (including the germanium-containing conductive layers 102, 112, 122, 132, and 142 and the insulating layer 103) in an etching process to expose a part of the substrate 101 (such as the first 2A is shown). Next, the memory layer 104a is deposited on the sidewalls and the bottom of the opening, and a semiconductor material such as polysilicon or germanium is deposited on the memory layer 104a to form the channel layer 104b (as shown in FIG. 2B). Thereafter, a hard mask layer 109 is deposited over the channel layer 104b to form a string 104 on the sidewalls of the opening 105 (as depicted in FIG. 2C).

Subsequently, the hard mask layer 109 and a portion of the memory layer 104a and the channel layer 104b are removed by non-isotropic etching, and a portion of the substrate 101 is exposed by the opening 105. The source 115 is selectively formed on the substrate 101 exposed by the polysilicon, and the string 104 is electrically connected to the substrate 101 as a ground layer of the vertical channel type three-dimensional NAND flash memory device 100 (for example, FIG. 2D) Drawn).

In addition, in the process of fabricating the series 104, a plurality of source contact structures 107 are further formed in the multilayer stack structure 10. The source contact structures 107 are arranged in the X-axis direction such that the series 104 are interposed between the adjacent two source contact structures 107 (please refer to FIG. 1C).

In the present embodiment, the source contact structure 107 is formed by forming a plurality of turns along the Y-axis in the germanium conductive layers 102, 112, 122, 132, and 142 and the insulating layer 103 by an etching process while forming the opening 105. A strip-shaped opening 108 extending in the direction to expose a portion of the substrate 101. Thereafter, a dielectric material layer 107a is formed on the sidewall of the strip opening, and the strip opening 108 is filled with a conductive material 107b, such as a polysilicon, to form a plurality of strip-shaped source contact structures extending along the Y-axis direction. 107.

Next, the uppermost germanium-containing conductive layer 102 is patterned to form a plurality of tandem select lines 106 in the germanium-containing conductive layer 102, and the tandem select lines are 106 extends in the X-axis direction. Referring to FIG. 1D and FIG. 1E, FIG. 1D is a partial structural perspective view showing a plurality of string selection lines 106 formed on the structure of the first B. Fig. 1E is a top view of the structure according to Fig. 1D. In some embodiments of the present invention, the step of patterning the uppermost germanium-containing conductive layer 102 includes forming a plurality of shallow trenches 111 on the germanium-containing conductive layer 102 to thereby partition the uppermost germanium-containing conductive layer 102 into A plurality of stripes, thereby defining a plurality of string selection lines 106.

Each of the series selection lines 106 corresponds to a part of the series of columns 104, and is electrically connected to the corresponding series 104. For example, in some embodiments of the invention, the strings 104 may be arranged in a matrix array, and each string selection line 106 may correspond to 5 to 10 rows of columns 104 and be aligned with the 5 to 10 rows. 104 electrical connection. In some embodiments of the present invention, the series 104 may be arranged in a honeycomb array manner, and each of the string selection lines 106 corresponds to 4 to 20 rows of the columns 104, and is electrically connected to the 4 to 20 rows of the arrays 104. Sexual links.

In the present embodiment, the series 104 are arranged in a honeycomb array manner, and each of the series selection lines 106 corresponds to the four rows of the arrays 104 and is electrically connected to the four rows of the arrays 104. By the same serial selection line 106, the memory cells of the series 104 corresponding to the four rows of serial selection lines 106 can be simultaneously read, thereby improving the operation speed. In addition, the series 104 does not use a metal gate, so that it is not necessary to reserve a space required for etching the trench between the string selection lines 106, so that the bandwidth of the string selection line 106 can be expanded. . Not only can the storage capacity of the vertical channel type three-dimensional NAND flash memory component 100 be increased, but also the vertical channel type three The overall power consumption of the NAND flash memory device 100 is reduced, thereby reducing interference between adjacent memory cells when the memory cell is read.

Follow-up. The multi-array multi-layer plug structures 110 are formed in the multi-layer stack structure 10, arranged in the X-axis direction, and the plurality of strings 104 are respectively sandwiched between the adjacent two-layer plug structures 110. Additionally, while forming the multi-layered plug structure 110, a contact plug 114 is also typically formed on each of the series select lines 106. Referring to FIG. 1F and FIG. 1G, FIG. 1F is a partial structural perspective view showing the complex array multilayer plug structure 110 and the contact plug 114 formed on the structure of FIG. 1D. The 1Gth image is a top view of the structure according to FIG. 1F.

In the present embodiment, each of the multi-layer plug structures 110 includes a plurality of via plugs, such as 110a, 110b, 110c, and 110d; and each of the via plugs 110a, 110b, 110c, and 110d and the germanium-containing conductive layer One of 112, 122, 132, and 142 is correspondingly turned on. The via plug 110a and the germanium-containing conductive layer 112 are respectively turned on; the via plug 110b and the germanium-containing conductive layer 122 are electrically connected; the via plug 110c and the germanium-containing conductive layer 132 are electrically connected; and the via plug 110d It is electrically connected to the conductive layer 142. The plugs 110a, 110b, 110c, and 110d of the same group of multi-layer plug structures 110 are arranged in the Y-axis direction to form a straight staircase structure parallel to the Y-axis direction. However, the linear stepped structure is not limited thereto. In another embodiment of the present invention, the plugs 110a, 110b, 110c, and 110d of the same group of multi-layer plug structures 110 may be divided into multiple arrays, for example, two groups. Arranged along the Y-axis direction to form two linear stepped structures parallel to the Y-axis direction (as shown in Figure 3) Drawn).

It should be noted that the distance D1 between two adjacent multi-layer plug structures 110 is determined by referring to the overall resistance value of the germanium-containing conductive layers 112, 122, 132 and 142 between the two adjacent multi-layer plug structures 110. And consider the operational performance of the vertical channel type three-dimensional NAND flash memory component 100. In some embodiments of the invention, the distance D1 between two adjacent multi-layer plug structures 110 may be substantially between 500 microns and 50 microns. Preferably, it can be substantially 100 microns.

In addition, the distance D2 between the two adjacent source contact structures 107 is determined by reference to the overall resistance value of the substrate 101 (ground layer) between the two adjacent source contact structures 107, and the vertical channel type three-dimensional NAND fast. The operational performance of the flash memory component 100. In some embodiments of the invention, the distance between adjacent two source contact structures 107 may be substantially greater than or equal to 20 micrometers (μm).

It should be noted that although in the foregoing embodiment (for the sake of simplicity), the distance between two adjacent source contact structures 107 and the distance between two adjacent multi-layer plug structures 110 are shown as Roughly the same. That is to say, one source contact structure 107 corresponds to a set of multi-layer plug structures 110. However, the configuration of the source contact structure 107 and the multilayer plug structure 110 is not limited thereto. In other embodiments of the invention, the distance between two adjacent source contact structures 107 and the distance between two adjacent multi-layer plug structures 110 may be different. In other words, more source contact structures 107 may be included between two adjacent multi-layer plug structures 110. Subsequently, a plurality of source lines 118 are formed over the source contact structures 107 such that the source lines 118 extend in the Y-axis direction and are electrically connected to the source contact structures 107. And in the series A plurality of bit lines 116 are formed above the select line 106 such that each bit line 116 extends in the Y-axis direction and is electrically connected to a string 104 in the same string select line 106. Referring to FIG. 1H, FIG. 1H is a structural top view after forming a plurality of source lines 118 and bit lines 116 on the structure of FIG. 1G. In the present embodiment, source line 118 and bit line 116 are parallel and both are orthogonal to series select line 106.

In some embodiments of the invention, source line 118 and bit line 116 may be formed in the same or different metal interconnect layer M1. For example, please refer to FIG. 4A and FIG. 4B. FIG. 4A is a partial structural sectional view taken along a tangent line S1 illustrated in FIG. 1H; FIG. 4B is a tangent S2 along the first FIG. A partial structural cross-sectional view is shown. In the present embodiment, the source line 118 and the bit line 116 are formed in the same metal layer inner wiring layer M1. Each of the bit lines 116 is electrically connected to a corresponding string 104 by a via 119 located between the string 104 and the metal interconnect layer M1.

It should also be noted that although in the foregoing embodiments, the substrate 101 is used as a grounding layer, the source 115 of the string 104 passes through the substrate 101 and the source contact structure 107 and the source line 118. Electrical connection. However, the ground layer structure of the vertical channel type three-dimensional NAND flash memory device 100 is not limited thereto. Referring to FIG. 5, FIG. 5 is a cross-sectional view showing a portion of a ground layer 301, a source contact structure 107, and a source line 118 according to another embodiment of the present invention.

In this embodiment, the structure of FIG. 5 and the structure class of FIG. 4B The difference is that the ground layer 301 may be another conductive material layer between the substrate 101 and the germanium-containing conductive layer 142. The source 115 of the series 104 is electrically connected to the source line 118 through the ground layer 301 and the source contact structure 107. The substrate 101 and the ground layer 301, and the ground layer 301 and the germanium-containing conductive layer 142 are separated by an insulating layer 303, respectively.

Next, a plurality of metal word lines 117a, 117b, 117c, and 117d are formed over the multilayer plug structure 110, the bit line 116, and the source line 118, extending in the X-axis direction, and each metal word line 117a is extended. 117b, 117c or 117d is electrically connected to a plurality of via plugs 110a, 110b, 110c or 110d conducting the same germanium-containing conductive layer 112, 122, 132 or 142. In addition, while the metal word lines 117a, 117b, 117c, and 117d are formed, the series metal lines 113 are generally formed to be electrically connected to the contact plugs 114 connected to the series selection lines 106.

For example, please refer to FIG. 1I. FIG. 1I is a structural top view showing a plurality of metal word lines 117a, 117b, 117c, and 117d and a series metal line 113 formed on the structure of FIG. 1H. In the present embodiment, the metal word line 117a is electrically connected to the plurality of via plugs 110a located in the different sets of the multi-layer plug structures 110 and simultaneously conducting the germanium-containing conductive layer 112; the metal word lines 117b are located The plurality of via plugs 110b of the different sets of multi-layer plug structures 110 and simultaneously conducting the germanium-containing conductive layer 122 are electrically connected; the metal word lines 117c are located in different sets of the multi-layer plug structures 110, and simultaneously turn on the germanium The plurality of via plugs 110c of the conductive layer 132 are electrically connected; the metal word lines 117c are electrically connected to the plurality of via plugs 110c located in the different sets of the multi-layer plug structures 110 and simultaneously conducting the germanium-containing conductive layer 132. .

The plugs 110a, 110b, 110c, and 110d of the same group of multi-layer plug structures 110 are arranged in the order of the height of the linear stepped structure, and the metal word lines 117a, 117b, 117c, and 117d arranged in the order of position correspond to each other. And electrically connected. For example, in the present embodiment, the plug 110a is correspondingly and electrically connected to the metal word line 117a; the plug 110b is correspondingly and electrically connected to the metal word line 117b; the plug 110c is correspondingly and electrically connected to the metal word line 117c; The plug 110d corresponds to and electrically connects the metal word line 117d. In other words, the configuration of the plugs 110a, 110b, 110c, and 110d of the same set of multi-layer plug structures 110 must match the position of the metal word lines 117a, 117b, 117c, and 117d. In some embodiments of the invention, the spacing between the metal word lines 117a, 117b, 117c, and 117d is equal to each other. Thus the configuration of the plugs 110a, 110b, 110c and 110d in the same set of multi-layer plug structures 110 can be in an equidistant configuration.

However, in other embodiments of the present invention, the configurations of the plugs 110a, 110b, 110c, and 110d in the same plurality of multi-layer plug structures 110 may be unequal configurations. Please refer to FIG. 6A and FIG. 6B. FIG. 6A is a partial structural sectional view taken along line S3 shown in FIG. 1I; FIG. 6B is a tangent line S4 shown along FIG. 1I. A partial structural cross-sectional view. In the present embodiment, since the metal word lines 117a, 117b, 117c, and 117d are formed in the same metal interconnect layer M2 as the series metal lines 113 connecting the contact plugs 114, and have the same extending direction. . In other words, the series metal wires 113 are interposed between the metal word lines 117a, 117b, 117c, and 117d.

Therefore, in order to avoid the plugs 110a, 110b, 110c and 110d and The series metal wires 113 generate an unnecessary electrical connection. In the present embodiment, the distance P2 between the plugs 110b and 110c of the same group of multi-layer plug structures 110 is larger than that of the same group of multi-layer plug structures 110. The distance P2 between 110a and 110b or the distance P3 between the plugs 110c and 110d is long. Among them, the distances P3 and P3 can be equal.

In some embodiments of the invention, there may be at least N unequal distances in the configuration of plugs 110a, 110b, 110c, and 110d in the same set of multi-layer plug structures 110. Where N is equal to the number of tandem metal lines 113 (or equal to the string select line 106) that are interleaved with the plugs 110a, 110b, 110c, and 110d of the same set of multi-layer plug structures 110. Subsequent processing of a plurality of subsequent stages (not shown) completes the preparation of the vertical channel type three-dimensional NAND flash memory device 100 (shown in FIG. 1I). Since, in an embodiment of the present invention, the vertical channel type three-dimensional NAND flash memory device 100 employs germanium-containing conductive layers 112, 122, 132, and 142 as gates; and by the multi-layer plug structure 110 and metal characters The arrangement of lines 117a, 117b, 117c and 117 reduces the overall resistance of the gates of the germanium-containing conductive layers 112, 122, 132 and 142, even to the same resistance as the metal gate, which reduces the gate resistance and capacitance. The resulting signal transmission delay phenomenon. Therefore, with the vertical channel type three-dimensional NAND flash memory device 100 provided by the present invention, the metal gate process can be avoided, and the vertical channel type three-dimensional NAND flash memory device 100 is caused by over-plating etching or residual sacrificial layer. Bad effects. In addition, it is not necessary to form a trench for etching the sacrificial layer in the multilayer stacked structure 10 during the fabrication of the vertical channel type three-dimensional NAND flash memory device 100. Therefore, the distance between two adjacent string selection lines 106 can be reduced to further increase the frequency bandwidth of the string selection line 106. Degree, increase the number of strings 104 that can be accommodated, and expand the memory space capacity.

Referring to FIG. 7, FIG. 7 is a partial structural top view of a three-dimensional memory device 200 according to another embodiment of the present invention. The structure of the three-dimensional memory element 200 is similar to the vertical channel type three-dimensional NAND flash memory element 100, except that the three-dimensional memory element 200 has a greater number of multi-layer plug structures 110 and source contact structures 107. In a macroscopic view, the multi-layer plug structure 110 overlaps each of the string selection lines 106 extending along the X direction, and each of the string selection lines 106 is divided into a plurality of regions A. In the present embodiment, the multi-layer plug structure 110 separates each of the string selection lines 106 into at least 10 regions A. Each of the regions A is provided with a contact plug 114 electrically connected to a decoder (not shown) via a series of metal wires 113.

For clarity of description, FIG. 5 omits some of the elements, such as metal word lines 117a, 117b, 117c, and 117d, and source lines 118, which are not shown. Those skilled in the art will be able to understand the configuration of the three-dimensional memory element 200 from the foregoing description and with reference to the related drawings.

According to the above embodiment, the present invention provides a memory element and a method of fabricating the same. The multi-layer plug structure in which the multiple arrays are arranged in parallel along the tandem selection line in the multi-layer stack structure of the three-dimensional memory element, and the plurality of strings formed in the multi-layer stack structure are respectively sandwiched between two adjacent ones. Between the multi-layer plug structures, and each of the interposer plugs included in the multi-layer plug structure is respectively turned on corresponding to a germanium-containing conductive layer in the multi-layer stack structure. And electrically connecting a plurality of via plugs that are connected to the same conductive layer containing germanium by metal word lines. By multi-layer plug structure and The connection of the metal word lines reduces the overall resistivity of the gate layer in the three-dimensional memory element to reduce the signal transmission delay caused by the gate resistance and capacitance. Moreover, since the three-dimensional memory component uses a germanium-containing conductive material as a gate, it is not necessary to form a metal gate, which can enlarge the bandwidth of the string selection line, and solve the conventional technique because of the storage capacity caused by the metal gate process. And the problem that the process yield cannot be improved.

In some embodiments of the present invention, the method further includes forming a plurality of source contact structures in the multi-layer stack structure of the three-dimensional memory element, the extending direction of the parallel string selection lines are arranged, and the plurality of strips are formed in the multi-layer stack structure. The strings are respectively sandwiched between two adjacent source contact plugs and vertically connected through the multilayer stack structure to be electrically connected to the substrate. By setting the source contact structure, the overall resistivity of the source in the three-dimensional memory device can be reduced to reduce the signal transmission delay caused by the source resistance and the capacitance.

While the invention has been described above in the preferred embodiments, it is not intended to limit the invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

10‧‧‧Multilayer stacking structure

100‧‧‧Vertical channel type three-dimensional NAND flash memory components

112, 122, 132 and 142‧‧‧矽 conductive layers

103‧‧‧Insulation

104‧‧‧Listing

104a‧‧‧ memory layer

104b‧‧‧channel layer

106‧‧‧Sequence selection line

107‧‧‧Source contact structure

110‧‧‧Multilayer plug structure

110a, 110b, 110c and 110d‧‧‧ interlayer plugs

113‧‧‧Serial wire

114‧‧‧Contact plug

116‧‧‧ bit line

117a, 117b, 117c and 117d‧‧‧ metal word lines

118‧‧‧ source line

S1, S2, S3 and S4‧‧‧ tangent

Claims (10)

A memory component comprising: a plurality of germanium-containing conductive layers stacked vertically parallel to each other on a substrate; a plurality of string selection lines (SSLs) located above the germanium-containing conductive layers and along a Extending in a first direction; a plurality of strings are perpendicular to the germanium-containing conductive layers and the plurality of string select lines, and are electrically connected to the plurality of string select lines; a plurality of bit lines, Located above the serial selection lines and extending along a second direction, respectively electrically connected to the series; the multi-array multi-layer plug structure is arranged along the first direction, and the series are respectively clipped Provided between adjacent ones of the plurality of plug structures; wherein each of the plurality of plug structures comprises a plurality of via plugs, each of the via plugs and one of the germanium-containing conductive layers Corresponding to conducting; and a plurality of metal strapped word lines extending along the first direction; wherein each of the metal word lines and the same one of the same one of the conductive layers containing germanium The layer plug is electrically connected. The memory device of claim 1, wherein two adjacent ones of the plurality of plug structures have a distance substantially between 500 micrometers (μm) and 50 micrometers. The memory device of claim 1, wherein the plugs of each of the plurality of plug structures are arranged along the second direction to form a staircase structure. The memory device of claim 3, wherein the plugs of each of the plurality of plug structures have at least N different pitches from each other, wherein N is equal to each of the series of select lines . The memory component of claim 1, wherein the plurality of plug structures overlap each of the plurality of string selection lines, and each of the plurality of string selection lines is divided into a plurality of regions; Each of the regions is electrically connected to a series of metal wires by a contact plug. The memory device of claim 1, further comprising: a plurality of source contact structures arranged along the first direction such that the series of strings are respectively sandwiched between the source contact structures Adjacent between the two. The memory device of claim 6, wherein each of the source contact structures extends in a strip shape along the second direction and extends perpendicularly through the germanium-containing conductive layers, and The substrate is electrically connected. The memory device of claim 6, further comprising: a ground layer between the germanium-containing conductive layer and the substrate; and a plurality of sources, each of the series passing through the sources One of the poles is in electrical contact with the ground plane; wherein each of the source contact structures is in electrical contact with the ground plane. A method for fabricating a memory device, comprising: forming a plurality of germanium-containing conductive layers vertically stacked and parallel to each other on a substrate; forming a plurality of strings vertically penetrating the germanium-containing conductive layers; and the germanium-containing conductive layers Forming a plurality of string selection lines, and extending the series selection lines in a first direction, and electrically connecting the corresponding series; forming a multi-array multi-layer plug structure, arranged along the first direction The plurality of plug structures are respectively disposed between adjacent ones of the plurality of plug structures; wherein each of the plurality of plug structures comprises a plurality of via plugs, each of the vias The plug is electrically connected to one of the conductive layers containing the germanium; forming a plurality of bit lines above the series of select lines, so that the bit lines extend in a second direction, and the plurality of the series Electrical connection; Forming a plurality of metal word lines above the plurality of plug structures to extend the metal word lines along the first direction; wherein each of the metal word lines is the same as conducting the germanium-containing conductive layers The interlayer plugs are electrically connected. The method for fabricating a memory device according to claim 9, further comprising forming a plurality of source contact structures arranged along the first direction such that the series of strings are respectively sandwiched between the source sources Adjacent to the contact structure.