TWI599021B - Memory device and method for fabricating the same - Google Patents

Description

Memory element and method of manufacturing same

The present invention 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.

As technology advances, advances in electronic components have increased the need for greater storage capacity. In order to increase storage capacity, memory elements become smaller and more cumulative. Therefore, three-dimensional memory components have gradually received high attention from the industry.

However, as the degree of integration of the three-dimensional memory element increases, defects in the vertical gate process are also increased due to the high aspect ratio and the complex film stack. The above defects include the phenomenon of the BL channel bending and the word line bridge (WL bridge). Therefore, how to develop a memory element with high integration and its manufacturing method to avoid the bending of the bit line channel and the word line bridge will become an important issue in the future.

The invention provides a memory element and a manufacturing method thereof, which can solve the problem of bending and word line bridging of a bit line channel on a vertical gate process.

The invention provides a memory element and a manufacturing method thereof, which can be applied to a charge trapping memory, a non-volatile memory and an embedded memory.

The present invention provides a memory element comprising a plurality of gate pillar structures and a plurality of dielectric pillars alternately disposed in the same direction and buried in the stacked layers to divide the stacked layers into a plurality of stacked structures.

In an embodiment of the invention, the memory element includes a substrate, a plurality of word lines, a plurality of isolation structures, the stacked structure, the gate pillar structure, and the dielectric post. The substrate has a plurality of first regions and a plurality of second regions, wherein the first regions and the second regions alternate with each other along the first direction. A plurality of word lines are located on the substrate, each word line extending along the first direction and traversing the first and second regions. A plurality of isolation structures are located on the substrate between adjacent two word lines, each isolation structure extending along the first direction and traversing the first and second regions. The stack structure is located on the word line and the isolation structure of the second area, and each stack structure extends along the second direction. A plurality of gate pillar structures are located in the first zone, and each gate pillar structure extends in the third direction. Each gate pillar structure includes a conductor post and a charge storage layer. The bottom of each conductor post is electrically connected to the corresponding word line. Each charge storage layer is located around the corresponding conductor post to electrically isolate the corresponding stack structure and the conductor post. The first direction is different from the second direction and is different from the third direction. The dielectric column is located in the first zone Off the structure. The dielectric pillars extend along the third direction and alternate with the gate pillar structure along the second direction to electrically isolate the gate pillar structure from the stacked structure.

In an embodiment of the invention, the shape of the sidewall of the stacked structure of the second region between the gate pillar structure of the adjacent two first regions and the dielectric post includes a zigzag or wave shape.

In an embodiment of the invention, each of the stacked structures includes a plurality of insulating layers and a plurality of conductor layers, wherein the insulating layer and the conductor layers are alternately stacked along the third direction.

In an embodiment of the invention, the gate pillar structures on both sides of each of the stacked structures are configured as a dual gate structure.

The present invention provides a method of manufacturing a memory element, the steps of which are as follows. A substrate is provided, the substrate having a plurality of first regions and a plurality of second regions. The first zone and the second zone alternate with each other along the first direction. A plurality of word lines are formed on the substrate. Each word line extends along a first direction and traverses the first zone and the second zone. An isolation structure is formed between each word line. Each of the isolation structures extends along the first direction and traverses the first zone and the second zone. The word line and the isolation structure alternate with each other along the second direction. A stacked layer is formed on the substrate. A plurality of first holes are formed in the stacked layers on the word line of the first region to expose the top surface of the word line. A gate pillar structure is formed in each of the first holes. Each gate post structure extends in a third direction. Each gate pillar structure includes a conductor post and a charge storage layer. The bottom of each conductor post is electrically connected to the corresponding word line. Each charge storage layer is located around the corresponding conductor post to electrically isolate the corresponding stacked layer and the conductor post. The first direction is different from the second direction, and the first The three directions are different. A plurality of second holes are formed in the stacked layers on the isolation structure of the first region to expose the top surface of the isolation structure. The second hole and the gate post structure alternate with each other along the second direction. Each of the second holes and the adjacent gate pillar structures are in contact with each other such that the stacked layers form a plurality of stacked structures in the second region. The above stacked structure extends in the second direction. A dielectric post is formed in each of the second holes. The dielectric posts extend along the third direction and alternate with the gate pillar structures along the second direction to electrically isolate the gate pillar structure from the stacked structure.

In an embodiment of the invention, the step of forming the corresponding gate pillar structure in each of the first holes is as follows. A layer of charge storage material is formed on the substrate. A layer of charge storage material covers the top surface of the stacked layer, the sidewalls of the first hole, and the top surface of the word line. An anisotropic etching process is performed to remove a portion of the charge storage material layer to expose the top surface of the stacked layer and the word line to form a charge storage layer on the sidewall of each of the first holes. Thereafter, conductor posts are formed in each of the first holes such that each charge storage layer is located around the corresponding conductor posts.

In an embodiment of the invention, the step of forming the corresponding dielectric post in each of the second holes is as follows. A layer of dielectric material is formed on the substrate. The layer of dielectric material is filled into the second hole. Thereafter, a planarization process is performed on the dielectric material layer to expose the gate pillar structure and the top surface of the stacked structure.

In an embodiment of the invention, each of the stacked structures includes a plurality of insulating layers and a plurality of conductor layers. The insulating layer and the conductor layer are alternately stacked in the third direction.

The invention provides a method of manufacturing a memory element, comprising forming on a substrate In a stacked layer, a plurality of gate pillar structures and a plurality of dielectric pillars are buried in the stacked layers. The gate pillar structure and the dielectric pillars are alternately arranged in the same direction, and the stacked layers are divided into a plurality of stacked structures.

In an embodiment of the invention, the step of embedding a plurality of gate pillar structures and a plurality of dielectric pillars in the stacked layer is as follows. A plurality of first holes are formed in the stacked layers. A gate pillar structure is formed in the first hole. A plurality of second holes are formed in the stacked layer, wherein each of the second holes alternates with the adjacent gate post structure. A dielectric post is formed in the second hole.

In an embodiment of the invention, the step of forming a gate pillar structure in the first hole includes: forming a charge storage layer in each of the first holes; and forming on the charge storage layer in each of the first holes Conductor column.

Based on the above, the present invention utilizes an individual etching process and a deposition process to embed a plurality of gate pillar structures and a plurality of dielectric pillars in the stacked layer, so that the stacked layers are divided into a plurality of stacked structures (for example, as bit lines). . Therefore, the memory element and the manufacturing method thereof of the embodiment of the invention can avoid the problem of the bending of the bit line channel and the word line bridge, so as to improve the reliability of the product.

The above described features and advantages of the invention will be apparent from the following description.

10, 20‧‧‧ holes

100‧‧‧Base

102‧‧‧Isolation

104‧‧‧ character line

105‧‧‧Isolation structure

106‧‧‧Stacking

106a, 114b‧‧‧ conductor layer

106b, 114a‧‧‧ insulation

108‧‧‧ gate pillar structure

110‧‧‧Charge storage layer

112‧‧‧Conductor column

114‧‧‧Stack structure

116‧‧‧ dielectric column

D1, D2, D3‧‧‧ direction

R1, R2‧‧‧

1A-1E illustrate the fabrication of a memory device in accordance with an embodiment of the invention. A top view of the process.

2A to 2E are schematic cross-sectional views taken along line A-A' of Figs. 1A to 1E, respectively.

1A-1E are schematic top views of a manufacturing process of a memory device according to an embodiment of the invention. 2A to 2E are schematic cross-sectional views taken along line A-A' of Figs. 1A to 1E, respectively.

Referring to FIG. 1A and FIG. 2A simultaneously, the substrate 100 is, for example, a semiconductor substrate, a semiconductor compound substrate, or a semiconductor substrate (Semiconductor Over Insulator (SOI)). The semiconductor is, for example, an atom of the IVA group, such as ruthenium or osmium. The semiconductor compound is, for example, a semiconductor compound formed of atoms of Group IVA, such as tantalum carbide or germanium telluride, or a semiconductor compound formed of a group IIIA atom and a group VA atom, such as gallium arsenide. The substrate 100 has a plurality of first regions R1 and a plurality of second regions R2. The first region R1 and the second region R2 extend in the second direction D2 and alternate with each other along the first direction D1. The second direction D2 is different from the first direction D1. In an embodiment, the first direction D1 is substantially perpendicular to the second direction D2.

Next, a plurality of word lines 104 are formed on the substrate 100. Each word line 104 extends along a first direction D1 and traverses the first region R1 and the second region R2. Specifically, a word line material layer (not shown) is formed on the substrate 100. Thereafter, a lithography process and an etch process are performed on the word line material layer to form a plurality of word lines 104 on the substrate 100. The above etching process can be, for example, a dry etching process. Dry etching The process can be, for example, Reactive Ion Etching (RIE). The material of the word line 104 may include polysilicon, metal halide, metal, or a combination thereof, and the formation method thereof may be formed by chemical vapor deposition. The metal halide may be, for example, tungsten or cobalt telluride, nickel telluride, titanium telluride, copper telluride, molybdenum telluride, antimony telluride, antimony telluride, zirconium telluride, or antimony telluride.

An isolation structure 105 is then formed between adjacent two word lines 104. Each isolation structure 105 extends along the first direction D1 and traverses the first region R1 and the second region R2. Specifically, a layer of isolation structural material (not shown) is formed on the substrate 100. Thereafter, the isolation structure material layer is etched back to form an isolation structure 105 between each word line 104. The isolation structure 105 is disposed between adjacent two word lines 104, and the word lines 104 and the isolation structures 105 alternate with each other along the second direction, which electrically isolates each word line 104 from each other. The material of the isolation structure 105 includes ruthenium oxide or a low dielectric constant material layer having a dielectric constant of less than 4, and the formation method thereof can be formed by chemical vapor deposition.

Referring to FIG. 1B and FIG. 2B simultaneously, a stacked layer 106 is formed on the substrate 100. The stacked layer 106 includes a plurality of insulating layers 106a and a plurality of conductor layers 106b, wherein the insulating layers 106a and the conductor layers 106b are alternately stacked along the third direction D3. The third direction D3 is different from the first direction D1 and is different from the second direction D2. In an embodiment, the third direction D3 is substantially perpendicular to the first direction D1 and the second direction D2, and the first direction D1 is substantially perpendicular to the second direction D2.

In an embodiment, the number of conductor layers 106b may include 8 layers, 16 layers, 32 layers, or more. Similarly, the insulating layer 106a is disposed on the adjacent two conductor layers 106b. Between, therefore, the insulating layer 106a may also include 8 layers, 16 layers, 32 layers or more. In an embodiment, the material of the insulating layer 106a may include ruthenium oxide, tantalum nitride, or a combination thereof, and the formation method thereof may be formed by chemical vapor deposition. The material of the conductor layer 106b may include doped polysilicon, undoped polysilicon, or a combination thereof, and the formation method thereof may utilize a chemical vapor deposition method.

Referring to FIG. 1C and FIG. 2C simultaneously, the stacked layer 106 is subjected to a lithography process and an etching process to form a plurality of first holes 10 in the stacked layer 106 on the word line 104 of the first region R1. The first hole 10 extends in the third direction to expose the word line 104 in the first region R1. In one embodiment, the shape of the first hole 10 can be, for example, a circle, a square, a rectangle, or an arbitrary shape, as long as the layer 106 can be penetrated to the word line 104 after the lithography process and the etching process. Each first hole 10 may have a size greater than or equal to the width of the corresponding word line 104 as long as each first hole 10 does not communicate with another first hole 10. The above etching process can be, for example, a dry etching process. The dry etching process can be, for example, a reactive ion etching process.

Referring to FIG. 1D and FIG. 2D simultaneously, a gate pillar structure 108 is formed in each of the first holes 10. Each gate post structure 108 extends along a third direction D3. Each gate pillar structure 108 includes a charge storage layer 110 and a conductor pillar 112 (eg, as a control gate). The bottom of each conductor post 112 is electrically connected to the corresponding word line 104. Thus, each conductor post 112 can be considered an extension of the corresponding word line 104, which has the effect of a word line. Each charge storage layer 110 is located around the corresponding conductor post 112 such that a plurality of conductor layers 106b of the corresponding stacked layer 106 And the conductor post 112 is electrically isolated. Specifically, the steps of forming the corresponding gate pillar structure 108 in each of the first holes 10 are as follows. First, a charge storage material layer (not shown) is formed on the substrate 100. The charge storage material layer covers the top surface of the stacked layer 106, the sidewalls of the first hole 10, and the top surface of the word line 104. Next, a layer of conductor material is formed on the layer of charge storage material. Thereafter, a chemical mechanical polishing process or an anisotropic etching process is performed to remove a portion of the charge storage material layer and the conductive material layer to expose the top surface of the stacked layer 106 and the word line 104 for each of the first holes 10 A charge storage layer 110 and a conductor post 112 are formed on the sidewall. In an embodiment, the material of the charge storage material layer may include a composite layer of an oxide layer, a nitride layer, or any combination thereof, and the composite layer may be three or more layers, and the present invention is not limited thereto. The method of forming the charge storage material layer may be a chemical vapor deposition method, a thermal oxidation method, or the like. For example, the charge storage material layer may include a composite layer such as an oxide layer/nitride layer/oxide layer (ONO), an oxide layer/nitride layer/oxide layer/nitride layer (ONON). In an embodiment, the material of the conductive material layer may include polysilicon, metal halide, metal, or a combination thereof, and the formation method thereof may be formed by chemical vapor deposition. The metal halide may be, for example, tungsten or cobalt telluride, nickel telluride, titanium telluride, copper telluride, molybdenum telluride, antimony telluride, antimony telluride, zirconium telluride, or antimony telluride.

Referring to FIG. 1E and FIG. 2E simultaneously, a plurality of dielectric posts 116 are formed in the stacked layer 106 on the isolation structure 105 of the first region R1. The dielectric posts 116 extend along the third direction D3 and alternate with the gate post structures 108 along the second direction D2 to electrically isolate the gate post structures 108 from the stacked structures 114.

Specifically, first, the lithography process and etching process are performed on the stacked layer 106. A plurality of second holes 20 are formed in the stacked layer 106 on the isolation structure 105 of the first region R1. The second hole 20 exposes the surface of the isolation structure 105 and extends in the third direction. The second hole 20 and the gate post structure 108 alternate with each other along the second direction D2. The sidewall of each of the second holes 20 exposes the gate pillar structure 108 adjacent thereto. In an embodiment, the shape of the second hole 20 may be, for example, a circle, a square, a rectangle or an arbitrary shape, as long as the top surface of the isolation layer 105 can be penetrated through the stacked layer 106 after the lithography process and the etching process. can. Each of the second holes 20 may have a size greater than or equal to the width of the corresponding isolation structure 105, as long as each of the second holes 20 can expose the corresponding gate post structure 108. In an embodiment, the etching process may be, for example, a dry etching process. The dry etching process can be, for example, a reactive ion etching process.

Next, a dielectric material layer (not shown) is formed on the substrate 100, and a dielectric material layer is filled in the second holes 20. The material of the dielectric material layer may include ruthenium oxide, tantalum nitride or a combination thereof, and the formation method thereof may be formed by chemical vapor deposition. A planarization process is then performed on the layer of dielectric material to expose the top surface of the gate pillar structure 108 and the stacked structure 114 such that a plurality of dielectric pillars 116 are formed in the second aperture 20. In an embodiment, the planarization process can be, for example, a Chemical-Mechanical Polishing (CMP) process.

In other words, by embedding the dielectric post 116 and the gate post structure 108 in the stacked layer 106 in the first region R1, the stacked layer 106 can be separated into a plurality of stacked structures 114. The stacked structure 114 extends along the second direction D2 between the dielectric post 116 and the gate post structure 108 in the adjacent two first regions R1 and traverses the majority of the word lines 104 with a plurality of isolation structures 105. When either the dielectric post 116 and the gate post structure 108 are not rectangular and of different sizes, the sidewalls of the stacked structure 114 are not planar, and the sidewall shape includes a zigzag or wave shape.

Referring to FIG. 1E and FIG. 2E simultaneously, the memory device of the embodiment of the present invention includes a substrate 100, a plurality of word lines 104, a plurality of isolation structures 105, a plurality of gate pillar structures 108, and a plurality of stacked structures 114 (for example, It is a plurality of bit lines) and a plurality of dielectric columns 116.

The substrate 100 has a plurality of first regions R1 and a plurality of second regions R2. The first zone R1 and the second zone R2 alternate with each other along the first direction D1. A majority of the word lines 104 are located on the substrate 100. Each word line 104 extends along a first direction D1 and traverses the first region R1 and the second region R2. A plurality of isolation structures 105 are located on the substrate 100 between adjacent two word lines 104. Each isolation structure 105 extends along the first direction D1 and traverses the first region R1 and the second region R2. Each of the stacked structures 114 extends along the second direction D2 and traverses the word line 104 of the second region R2 and the isolation structure 105. Each stacked structure 114 includes a plurality of insulating layers 114a and a plurality of conductor layers 114b. The insulating layer 114a and the conductor layer 114b are alternately stacked along the third direction D3 (as shown in FIG. 2E).

A plurality of gate pillar structures 108 are located within the first region R1. Each gate post structure 108 extends along a third direction D3. Each gate pillar structure 108 includes a charge storage layer 110 and a conductor pillar 112 (eg, as a control gate). The bottom of each conductor post 112 is electrically connected to the corresponding word line 104. Each charge storage layer 110 is located around the corresponding conductor post 112 to electrically isolate the corresponding stack structure 114 And the conductor column 112. The first direction D1 is different from the second direction D2 and is different from the third direction D3. In an embodiment, the third direction D3 is substantially perpendicular to the first direction D1 and the second direction D2, and the first direction D1 is substantially perpendicular to the second direction D2. A plurality of dielectric posts 116 are located on the isolation structure 105 in the first zone R1. The dielectric posts 116 extend along the third direction D3 and alternate with the gate post structures 108 along the second direction D2 to electrically isolate the gate post structures 108 from the stacked structures 114.

As shown in FIG. 1E and FIG. 2E, since the conductor posts 112 can be considered as extensions of the word lines 104, and each stacked structure 114 (eg, as a bit line) is located adjacent to the two conductor posts 112 (eg, as Control gate between). Thus, word line 104 can utilize the gate pillar structure 108 on both sides of stacked structure 114 as a dual gate structure to control the operation of the memory element of the present invention. The memory element of the present invention utilizes double-sided control of both sides of the stacked structure 114 to make the operation of the memory element more accurate than single-sided control.

In summary, the present invention utilizes an individual etching process and a deposition process to embed a plurality of gate pillar structures and a plurality of dielectric pillars in a stacked layer to separate the stacked layers into a plurality of stacked structures (for example, as a bit Yuan line). Since the gate pillar structure and the dielectric pillar are respectively formed by an etching process and a backfill material layer which are opened in the stacked layer, after the first hole is opened in the stacked structure, between the adjacent two first holes There are also remaining stack layers that provide support in the first direction and the second direction. When the second hole is opened in the stacked structure, the gate pillar structure can provide support in the first direction. Moreover, the dielectric post electrically isolates the gate pillar structure and the stacked structure. In this way, the memory element and the manufacturing method thereof of the embodiment of the invention can avoid the high stacking structure The aspect ratio causes the bending of the bit line channel and the problem of bridging the word line, thereby improving the reliability of the product.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

20‧‧‧ holes

104‧‧‧ character line

105‧‧‧Isolation structure

108‧‧‧ gate pillar structure

114‧‧‧Stack structure

116‧‧‧ dielectric column

D1, D2‧‧‧ direction

R1, R2‧‧‧

Claims (11)

A memory component comprising: a plurality of word lines on a substrate, wherein each word line extends along a first direction; a plurality of gate pillar structures and a plurality of dielectric pillars are alternately arranged along a second direction And buried in a stacked layer, the stacked layer is divided into a plurality of stacked structures, wherein each of the gate pillar structures comprises: a conductor pillar, the bottom of each conductor pillar and the corresponding character line electrical And a charge storage layer, each charge storage layer is located around the corresponding conductor post to electrically isolate the corresponding stack structure and the conductor post, wherein each stack structure comprises a plurality of insulating layers and a plurality of a conductor layer, wherein the insulating layers and the conductor layers are alternately stacked along a third direction. The memory device of claim 1, further comprising: the substrate having a plurality of first regions and a plurality of second regions, wherein the first regions and the second regions are along the first direction Alternating; the word lines traversing the first region and the second regions; a plurality of isolation structures are located on the substrate between adjacent two word lines, wherein each isolation structure is along The first direction extends and traverses the first region and the second regions; the stacked structures are located on the word lines of the second regions and the isolation structures, each stacked structure along Extending in the second direction and crossing the word lines The isolation structure; the gate pillar structures are located on the word lines in the first regions, and each gate pillar structure extends along the third direction, wherein the first direction and the second direction Different from the third direction; and the dielectric posts are located on the isolation structures in the first regions, and the dielectric posts extend along the third direction to electrically isolate the gates The column structure and the stacked structures. The memory device of claim 2, wherein the shape of the sidewall of the stacked structure of the second region between the gate pillar structures of the adjacent two first regions and the dielectric pillars comprises a sawtooth Shaped or wavy. The memory element of claim 1, wherein the gate pillar structures on both sides of each stacked structure form a double gate structure. A method of fabricating a memory device, comprising: providing a substrate having a plurality of first regions and a plurality of second regions, wherein the first regions and the second regions alternate with each other along a first direction; Forming a plurality of word lines on the substrate, each word line extending along the first direction, and traversing the first area and the second areas; forming an isolation structure between each word line Each of the isolation structures extends along the first direction and traverses the first region and the second regions, wherein the word lines and the isolation structures alternate with each other along a second direction; Forming a stacked layer on the substrate; forming a plurality of first layers in the stacked layers on the word lines of the first regions a hole to expose a top surface of the word lines; a gate pillar structure is formed in each of the first holes, each gate pillar structure extending along a third direction, wherein each gate pillar structure comprises: a conductor post, the bottom of each conductor post is electrically connected to the corresponding word line; and a charge storage layer, each charge storage layer is located around the corresponding conductor post to electrically isolate the corresponding one And a plurality of second holes formed in the stacked layers on the isolation structures of the first regions a top surface of the isolation structure, wherein the second holes and the gate pillar structures alternate along the second direction, and each of the second holes and the adjacent gate pillar structure are in contact with each other Having the stacked layer form a plurality of stacked structures in the second regions, wherein the stacked structures extend along the second direction; and forming a dielectric post in each of the second holes, the dielectric posts along the Extending in the third direction, and Gate post structure alternately along the second direction to electrically isolate the plurality of pillar structures and the gate stacked structure of these. The method of manufacturing a memory device according to claim 5, wherein the step of forming the corresponding gate pillar structure in each of the first holes comprises: forming a charge storage material layer on the substrate, the charge The storage material layer covers the top surface of the stacked layer, the sidewalls of the first holes, and the top surfaces of the word lines; performing an anisotropic etching process to remove a portion of the charge storage material layer to violently Exposing the stacked layer and the top surface of the word lines to form a charge storage layer on the sidewall of each of the first holes; and forming a conductor post in each of the first holes such that each charge storage layer is located Corresponding to the circumference of the conductor post. The method for manufacturing a memory device according to claim 5, wherein the step of forming the corresponding dielectric post in each of the second holes comprises: forming a dielectric material layer on the substrate, the dielectric material layer Filling in the second holes; and planarizing the dielectric material layer to expose the gate pillar structures and the top surfaces of the stacked structures. The method of manufacturing a memory device according to claim 5, wherein each of the stacked structures comprises a plurality of insulating layers and a plurality of conductor layers, wherein the insulating layers and the conductor layers are alternately stacked along the third direction . A method of fabricating a memory device, comprising: forming a stacked layer on a substrate; and embedding a plurality of gate pillar structures and a plurality of dielectric pillars in the stacked layer, the gate pillar structures and the dielectric pillars The stacked layers are alternately arranged in a same direction to divide the stacked layers into a plurality of stacked structures. The method of manufacturing a memory device according to claim 9, wherein the step of embedding a plurality of gate pillar structures and a plurality of dielectric pillars in the stacked layer comprises: forming a plurality of first layers in the stacked layer Hole Forming the gate pillar structures in the first holes; forming a plurality of second holes in the stacked layer, wherein each of the second holes alternates with the adjacent gate pillar structures; and The dielectric pillars are formed in the two holes. The method of manufacturing the memory device of claim 10, wherein the forming the gate pillar structures in the first holes comprises: forming a charge storage layer in each of the first holes; A conductor post is formed on the charge storage layer in each of the first holes.