阅读说明：本技术 存储器的形成方法及存储器 (Memory forming method and memory ) 是由 李冉 于 2020-05-22 设计创作，主要内容包括：本发明实施方式提供一种存储器的形成方法及存储器,存储器的形成方法,包括：提供基底,基底上形成有位线结构以及第一保护层；形成介质层填充相邻位线结构之间的间隙；形成第二保护层覆盖第一保护层顶部表面和介质层的顶部表面；在垂直于位线结构延伸的方向上,去除部分介质层以及部分第二保护层,形成电容接触孔,且在垂直于位线结构延伸的方向上,暴露出位于相邻电容接触孔之间的第一保护层；形成导电层填充电容接触孔并覆盖暴露出的第一保护层的顶部表面,且导电层顶部表面与第二保护层顶部表面齐平；刻蚀部分导电层形成分立的电容接触结构。(The embodiment of the invention provides a forming method of a memory and the memory, wherein the forming method of the memory comprises the following steps: providing a substrate, wherein a bit line structure and a first protective layer are formed on the substrate; forming a dielectric layer to fill the gap between the adjacent bit line structures; forming a second protective layer to cover the top surface of the first protective layer and the top surface of the dielectric layer; removing part of the dielectric layer and part of the second protective layer in the direction vertical to the extension direction of the bit line structure to form capacitor contact holes, and exposing the first protective layer positioned between the adjacent capacitor contact holes in the direction vertical to the extension direction of the bit line structure; forming a conductive layer to fill the capacitor contact hole and cover the exposed top surface of the first protective layer, wherein the top surface of the conductive layer is flush with the top surface of the second protective layer; etching part of the conductive layer forms a discrete capacitor contact structure.)

1. A method for forming a memory, comprising:

providing a substrate, wherein a bit line structure and a first protective layer positioned on the top surface of the bit line structure are formed on the substrate;

forming a dielectric layer to fill a gap between adjacent bit line structures, wherein the top surface of the dielectric layer is flush with the top surface of the first protective layer;

forming a second protective layer to cover the top surface of the first protective layer and the top surface of the dielectric layer;

removing part of the dielectric layer and part of the second protective layer in a direction perpendicular to the extension direction of the bit line structure to form capacitor contact holes, and exposing the first protective layer between the adjacent capacitor contact holes in the direction perpendicular to the extension direction of the bit line structure;

forming a conductive layer to fill the capacitor contact hole and cover the exposed top surface of the first protective layer, wherein the top surface of the conductive layer is flush with the top surface of the second protective layer;

and etching part of the conductive layer to form a discrete capacitor contact structure.

2. The method of claim 1, wherein etching portions of the conductive layer to form discrete capacitive contact structures comprises:

forming a contact mask layer on the top surfaces of the conductive layer and the second protective layer;

the contact mask layer exposes the conducting layer and the second protective layer with preset widths in a preset direction, and is perpendicular to the preset direction, and the contact mask layer, the exposed conducting layer and the second protective layer are alternately arranged; the included angle between the preset direction and the extending direction of the bit line structure is alpha, alpha is larger than 0 degree and is not equal to 90 degrees

Etching the exposed conductive layer until part of the top surface of the first protective layer is exposed;

and removing the contact mask layer, and taking the residual conducting layer as the capacitor contact structure.

3. The method of claim 1, wherein forming a bit line structure and a first passivation layer on a top surface of the bit line structure on the substrate comprises:

forming a bit line lamination on the substrate, and forming a first protective film on the top of the bit line lamination;

forming a patterned bit line mask layer on the top surface of the first protective film, and etching the first protective film and the bit line lamination by taking the bit line mask layer as a mask to form the bit line structure and a first protective layer on the top surface of the bit line structure;

and removing the bit line mask layer.

4. The method as claimed in claim 1, wherein the step of removing a portion of the dielectric layer and a portion of the second passivation layer in a direction perpendicular to the bit line structure to form a capacitor contact hole comprises:

forming a dielectric mask layer on the top surface of the second protective layer;

etching a part of the second protective layer in a direction perpendicular to the extension direction of the bit line structure by taking the dielectric mask layer as a mask until a part of the first protective layer and a part of the top surface of the dielectric layer are exposed;

and removing the exposed part of the dielectric layer to form the capacitor contact hole.

5. The method of claim 1, wherein after forming the capacitor contact hole and before forming the conductive layer to fill the capacitor contact hole, the method comprises:

forming an isolation film on the substrate, the isolation film covering the second protective layer and the exposed first protective layer, and the capacitor contact hole sidewalls and bottom;

and removing the isolation films on the top surface of the second protection layer, the exposed top surface of the first protection layer and the bottom of the capacitor contact hole to form an isolation layer on the side wall of the capacitor contact hole.

6. The method of claim 1, wherein the conductive layer comprises a first conductive layer and a second conductive layer, the first conductive layer and the second conductive layer are made of different materials, a top surface of the second conductive layer is flush with a top surface of the second passivation layer, and the second conductive layer further covers the top surface of the first passivation layer in the direction perpendicular to the bit line structure.

7. The method as claimed in claim 6, wherein the forming of the conductive layer fills the capacitor contact hole, and comprises:

forming the first conductive layer in the capacitor contact hole, wherein the top surface of the first conductive layer is lower than that of the first protective layer;

forming a top conductive film on the top surface of the first conductive layer, the top surface of the first protective layer, and the top surface of the second protective layer;

and etching the top conductive film to form the second conductive layer.

8. The method of claim 1, wherein after said forming the discrete capacitive contact structure, comprising:

forming an isolation mask layer on the top surface of the second protection layer;

patterning the second protective layer positioned at the top of the capacitor contact structure in the extending direction of the bit line structure by taking the isolation mask layer as a mask to expose the dielectric layer positioned between the capacitor contact structures;

removing the dielectric layer positioned between the capacitor contact structures to form an air gap;

forming a sealing layer that seals the top of the air gap.

9. A memory, comprising:

the device comprises a substrate and a bit line structure positioned on the substrate;

the first protective layer is positioned on the top surface of the bit line structure;

the capacitor contact structures and the isolation structures are alternately arranged in the extending direction of the bit line structures;

the second protective layer is positioned on the top surfaces of the first protective layer and the isolation structures between the adjacent bit line structures, and the extending direction of the second protective layer is perpendicular to the extending direction of the bit line structures;

the top of electric capacity contact structure has the arch, the arch is extended at the interval in predetermineeing the direction, the arch still is located part the top surface of first protective layer, predetermine the direction with the direction contained angle that the bit line structure extends is alpha, alpha is greater than 0 and alpha is not equal to 90.

10. The memory of claim 9, further comprising: and the isolation layer is positioned on the side wall of the isolation structure.

11. The memory of claim 10, wherein the isolation structure comprises a dielectric layer or an air gap.

Technical Field

The present invention relates to the field of semiconductors, and in particular, to a method for forming a memory and a memory.

Background

The method for manufacturing a Dynamic Random Access Memory (DRAM) mainly involves the manufacture of a Storage Node Contact (Storage Node Contact) in a Storage array region, a connection layer between a capacitor and a capacitor Contact pad (connecting pad), and an isolation structure between capacitor Contact structures.

With the continuous development of semiconductor integrated circuit device technology, how to optimize the process flow to effectively improve the production efficiency of the memory and reduce the production operation cost of the memory becomes crucial. The integration of memory process technology below 20nm increases the integration of semiconductor process technology, and the difficulty of reducing the size of the device is increasing.

Particularly, in the manufacturing process of the array region of the memory, the process flow of each device needs to overcome a series of process difficulties and some problems that can be avoided when the process flows are connected, which is a problem to be solved at present.

Disclosure of Invention

The embodiment of the invention provides a memory and a forming method thereof, which simplify the manufacturing process of the existing memory, further improve the production efficiency of the memory and reduce the production and operation cost of the memory.

In order to solve the above technical problem, an embodiment of the present invention provides a method for forming a memory, including: providing a substrate, wherein a bit line structure and a first protective layer positioned on the top surface of the bit line structure are formed on the substrate; forming a dielectric layer to fill gaps between adjacent bit line structures, wherein the top surface of the dielectric layer is flush with the top surface of the first protective layer; forming a second protective layer to cover the top surface of the first protective layer and the top surface of the dielectric layer; removing part of the dielectric layer and part of the second protective layer in the direction vertical to the extension direction of the bit line structure to form capacitor contact holes, and exposing the first protective layer positioned between the adjacent capacitor contact holes in the direction vertical to the extension direction of the bit line structure; forming a conductive layer to fill the capacitor contact hole and cover the exposed top surface of the first protective layer, wherein the top surface of the conductive layer is flush with the top surface of the second protective layer; etching part of the conductive layer forms a discrete capacitor contact structure.

According to the embodiment of the invention, by adjusting the flow of the manufacturing process of the memory, when the bit line lamination is formed, a first protective layer is formed at the top of the bit line lamination, and a second protective layer is formed at the top of the first protective layer in the subsequent manufacturing process; the protective layer with staggered high and low levels is formed on the top of the bit line structure skillfully, which is beneficial to reducing the loss of the bit line structure in the etching process; and a top layer framework formed by protective layers with staggered high and low levels is utilized, and a connecting layer between the capacitor and the capacitor contact structure is ingeniously formed through one-step etching. The process flow of the manufacturing process of the memory at present is simplified, and further the production efficiency of the memory is improved and the production and operation cost of the memory is reduced.

In addition, etching portions of the conductive layer to form discrete capacitive contact structures, includes: forming a contact mask layer on the top surfaces of the conductive layer and the second protective layer; the contact mask layer exposes the conducting layer and the second protective layer with preset widths in a preset direction, and the contact mask layer, the exposed conducting layer and the second protective layer are alternately arranged in the direction perpendicular to the preset direction; an included angle between the preset direction and the extending direction of the bit line structure is alpha, alpha is larger than 0 degree and is not equal to 90 degrees, and the exposed conductive layer is etched until the top surface of a part of the first protective layer is exposed; and removing the contact mask layer, and taking the residual conductive layer as a capacitor contact structure.

In addition, be formed with bit line structure and the first protective layer that is located bit line structure top surface on the base, include: forming a bit line lamination on a substrate, and forming a first protective film on the top of the bit line lamination; forming a patterned bit line mask layer on the top surface of the first protective film, and etching the first protective film and the bit line lamination by taking the bit line mask layer as a mask to form a bit line structure and a first protective layer on the top surface of the bit line structure; and removing the bit line mask layer.

In addition, in the direction perpendicular to the extension direction of the bit line structure, removing part of the dielectric layer and part of the second protective layer to form a capacitor contact hole, including: forming a dielectric mask layer on the top surface of the second protective layer; etching part of the second protective layer in a direction perpendicular to the extension direction of the bit line structure by taking the dielectric mask layer as a mask until part of the first protective layer and part of the top surface of the dielectric layer are exposed; and removing the exposed part of the dielectric layer to form a capacitor contact hole.

In addition, after forming the capacitor contact hole and before forming the conductive layer to fill the capacitor contact hole, the method includes: forming an isolation film on the substrate, wherein the isolation film covers the second protective layer and the exposed first protective layer, and the side wall and the bottom of the capacitor contact hole; and removing the isolation films on the top surface of the second protection layer, the exposed top surface of the first protection layer and the bottom of the capacitor contact hole to form an isolation layer on the side wall of the capacitor contact hole. By forming the isolation layer between the dielectric layer and the subsequently formed capacitor contact structure, the parasitic capacitance between the subsequently formed capacitor contact structures is reduced.

In addition, the conducting layer comprises a first conducting layer and a second conducting layer, the materials of the first conducting layer and the second conducting layer are different, the top surface of the second conducting layer is flush with the top surface of the second protective layer, and the top surface of the second conducting layer is covered by the second conducting layer in the direction perpendicular to the extending direction of the bit line structure.

In addition, forming a conductive layer to fill the capacitor contact hole includes: forming a first conductive layer in the capacitor contact hole, wherein the top surface of the first conductive layer is lower than that of the first protective layer; forming a top conductive film on the top surface of the first conductive layer, the top surface of the first protective layer and the top surface of the second protective layer; and etching the top conductive film to form a second conductive layer.

In addition, after forming the discrete capacitive contact structure, the method comprises the following steps: forming an isolation mask layer on the top surface of the second protection layer; patterning a second protective layer positioned at the top of the capacitor contact structures in the extending direction of the bit line structures by taking the isolation mask layer as a mask to expose the dielectric layer positioned between the capacitor contact structures; removing the dielectric layer between the capacitor contact structures to form an air gap; forming a sealing layer, wherein the sealing layer seals the top of the air gap. The dielectric layer between the capacitor contact structures is positioned and removed on the first protective layer and the second protective layer to form an air gap so as to reduce the dielectric constant between the capacitor contact structures, thereby reducing the parasitic capacitance between the capacitor contact structures, and the air gap is important for reducing the integration level of the memory.

An embodiment of the present invention further provides a memory, including: the device comprises a substrate and a bit line structure positioned on the substrate; the first protective layer is positioned on the top surface of the bit line structure; the capacitor contact structures and the isolation structures are alternately arranged in the extending direction of the bit line structures; the second protective layer is positioned on the top surfaces of the first protective layer and the isolation structures between the adjacent bit line structures, and the extending direction of the second protective layer is vertical to the extending direction of the bit line structures; the top of the capacitor contact structure is provided with protrusions which extend at intervals in a preset direction, the protrusions are also located on the top surface of part of the first protection layer, an included angle between the preset direction and the extending direction of the bit line structure is alpha, and alpha is larger than 0 degrees and is not equal to 90 degrees.

In addition, the memory further comprises: and the isolation layer is positioned on the side wall of the isolation structure. And the parasitic capacitance between the capacitor contact structures is reduced through the isolation layer between the isolation structure and the capacitor contact structure.

In addition, the isolation structure includes a dielectric layer or an air gap. The dielectric layer is used as an isolation structure, and is formed when the gap between the bit line structures is filled, so that an additional process flow is not needed, and the production efficiency of the memory is improved; the air gap is used as an isolation structure, so that the dielectric constant between the capacitor contact structures can be effectively reduced, the parasitic capacitance between the capacitor contact structures is reduced, and the performance of the memory is improved.

Compared with the prior art, the top part of the formed capacitor contact structure is positioned on the top surface of the first protective layer, the arrangement mode of the original capacitor contact structure is changed, the connection between the subsequently formed capacitor and the capacitor contact structure becomes simple, the process flow of the manufacturing process of the current memory is improved, the production efficiency of the memory is improved, and the production and operation cost of the memory is reduced.

Drawings

One or more embodiments are illustrated by corresponding figures in the drawings, which are not to scale unless specifically noted.

Fig. 1-2 are schematic diagrams illustrating a bit line structure and a first passivation layer according to an embodiment of the invention;

FIGS. 3 to 5 are schematic views illustrating the formation of a dielectric layer and a second passivation layer according to an embodiment of the invention;

FIGS. 6 to 8 are schematic views illustrating the formation of capacitor contact holes according to an embodiment of the present invention;

FIGS. 9-14 are schematic diagrams illustrating the formation of a conductive layer in accordance with an embodiment of the present invention;

FIGS. 15-17 are schematic diagrams illustrating the formation of a capacitor contact structure according to an embodiment of the invention;

fig. 18 to 19 are schematic views illustrating formation of an air gap according to an embodiment of the present invention.

Detailed Description

At present, the manufacturing process of the memory is complex, the production efficiency of the memory is seriously influenced, and the production and operation cost of the memory is reduced.

To solve the above problem, a first embodiment of the present invention provides a method for forming a memory, including: providing a substrate, wherein a bit line structure and a first protective layer positioned on the top surface of the bit line structure are formed on the substrate; forming a dielectric layer to fill gaps between adjacent bit line structures, wherein the top surface of the dielectric layer is flush with the top surface of the first protective layer; forming a second protective layer to cover the top surface of the first protective layer and the top surface of the dielectric layer; removing part of the dielectric layer and part of the second protective layer in the direction vertical to the extension direction of the bit line structure to form capacitor contact holes, and exposing the first protective layer positioned between the adjacent capacitor contact holes in the direction vertical to the extension direction of the bit line structure; forming a conductive layer to fill the capacitor contact hole and cover the exposed top surface of the first protective layer, wherein the top surface of the conductive layer is flush with the top surface of the second protective layer; etching part of the conductive layer forms a discrete capacitor contact structure.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that in various embodiments of the invention, numerous technical details are set forth in order to provide a better understanding of the present application. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments. The following embodiments are divided for convenience of description, and should not constitute any limitation to the specific implementation manner of the present invention, and the embodiments may be combined with each other and referred to each other without contradiction.

The method for forming the memory of the present embodiment will be specifically described below with reference to fig. 1 to 19.

Referring to fig. 1 to 2, fig. 1 and 2 are schematic cross-sectional views of a substrate 10 perpendicular to a direction in which a bit line structure extends, the substrate 10 having a bit line structure 15 formed thereon and a first passivation layer 12 on a top surface of the bit line structure 15.

Specifically, referring to fig. 1, a substrate 10 is provided, the substrate 10 includes an array region and a peripheral region, and the substrate 10 includes a buried word line, a shallow trench isolation structure, an active region, and the like.

A bit line stack 11 is formed on a substrate 10, and the bit line stack 11 includes a bit line contact layer 111, a bottom dielectric layer 112, a metal layer 113, and a top dielectric layer stacked on the substrate 10.

The process of forming the bit line stack 11 on the substrate 10 specifically includes: forming a bit line contact layer 111 connected to an active region in the substrate 10 and separated therefrom on the substrate 10; forming an underlying dielectric layer 112 on the substrate 10 to fill the gap between the bit line contact layers 111, wherein the top surface of the underlying dielectric layer 112 is flush with the top surface of the bit line contact layer 111; forming a metal layer 113 on the top surface of the bottom dielectric layer 112 and the top surface of the bit line contact layer 111; a top dielectric layer 114 is formed on the top surface of metal layer 113.

The bit line contact layer 111 is made of tungsten or polysilicon, the bottom dielectric layer 112 and the top dielectric layer 114 are made of silicon nitride, silicon dioxide or silicon oxynitride, and the metal layer 113 is made of one or more conductive materials, such as doped polysilicon, titanium nitride, a composite of tungsten and tungsten, etc.

A first protective film 115 is formed on top of the bit line stack 11. The first protective film 115 is used to protect the bit line structure from being etched in a subsequent etching process. In the present embodiment, the material of the first protection film 115 is silicon oxynitride; in other embodiments, the material of the first protection film is formed by using an insulating material, such as silicon nitride or silicon oxide.

A patterned bit line mask layer 13 is formed on the top surface of the first protective film 115. It should be noted that the bit line mask layer 13 in fig. 1 is illustrated by taking a single-layer structure as an example, and it is clear to those skilled in the art that in an actual etching process, the bit line mask layer 13 may also be a stacked-layer structure.

Referring to fig. 2, the first protective film 115 and the bit line stack 11 are etched using the bit line mask layer 13 as a mask, the bit line structure 15 and the first protective layer 12 on the top surface of the bit line structure 15 are formed, and the bit line mask layer 15 is removed.

It should be noted that, in the cross section of the same bit line structure, only one of the adjacent bit line structures 15 is connected to the active region in the substrate 10 through the bit line contact layer 111, what is shown in fig. 2 is that the left bit line structure 15 and the right bit line structure 15 are connected to the active region in the substrate 10 through the bit line contact layer 111, and in other cross section drawings, only the middle bit line structure 15 may be connected to the active region in the substrate 10 through the bit line contact layer 111.

Referring to fig. 3 to 5, fig. 3 and 4 are schematic cross-sectional views in a direction parallel to the bit line structures, and fig. 5 is a schematic perspective view of a memory, in which a dielectric layer 16 is formed to fill the gaps between adjacent bit line structures 15, the top surface of the dielectric layer 16 is flush with the top surface of the first protection layer 12, and a second protection layer 17 is formed on the top surface of the first protection layer 12 and the top surface of the dielectric layer 16.

Specifically, referring to fig. 3, a dielectric film (not shown) is formed to fill the gap between the adjacent bit line structures and cover the bit line structures 15, and the dielectric film (not shown) is etched to form a dielectric layer 16.

In the present embodiment, the material of the dielectric layer 16 is silicon oxide, and in other embodiments, the material of the dielectric layer 16 is formed by using other insulating materials, such as silicon nitride or silicon oxynitride.

In this embodiment, the dielectric film (not shown) is formed by spin coating, and the dielectric film (not shown) formed by spin coating has an advantage of good filling property.

Referring to fig. 4, a second protective layer 17 is formed on the top surface of the first protective layer 12 and the top surface of the dielectric layer 16.

In the present embodiment, the material of the second protective layer 17 is the same as that of the first protective layer 12; in other embodiments, the material of the second protective layer may be different from the material of the first protective layer.

The top layer framework formed by the first protective layer 12 and the second protective layer 17 effectively improves the arrangement mode of the top of the capacitor contact structure in the subsequent process of forming the capacitor contact structure, so that the capacitor contact structure is directly connected with the lower electrode plate of a capacitor to be formed subsequently, and the formation process of the memory is effectively improved. It should be noted that, the thicknesses of the first protection layer 12 and the second protection layer 17 are not limited in the embodiments of the present invention, and the thicknesses of the first protection layer 12 and the second protection layer 17 may be set according to specific process requirements.

After the second passivation layer 17 is formed, the spatial structure of the memory is shown in fig. 5.

Referring to fig. 6 to 8, fig. 6 and 7 are schematic cross-sectional views parallel to the extending direction of the bit line structure, and fig. 8 is a schematic perspective view of a memory, in which a portion of the dielectric layer 16 and a portion of the second passivation layer 17 are removed in a direction perpendicular to the extending direction of the bit line structure 15 to form capacitor contact holes 18, and in the direction perpendicular to the extending direction of the bit line structure 15, the first passivation layer 12 located between adjacent capacitor contact holes 18 is exposed.

Specifically, referring to fig. 6, a dielectric mask layer 19 is formed on the top surface of the second protective layer 17.

It should be noted that the dielectric mask layer 19 in fig. 6 is illustrated by taking a layer as an example, and it is clear to those skilled in the art that in the actual etching process, the dielectric mask layer 19 may be a stacked structure.

Referring to fig. 7, using the dielectric mask layer 19 as a mask, the second passivation layer 17 is etched in a direction perpendicular to the extension direction of the bit line structure 15 until a portion of the first passivation layer 12 and a portion of the dielectric layer 16 are exposed, and the exposed portion of the dielectric layer 16 is removed to form the capacitor contact hole 18.

The schematic perspective structure of the memory formed at this time is shown in fig. 8.

Referring to fig. 9, in the present embodiment, after forming the capacitor contact hole 18 and before forming the conductive layer to fill the capacitor contact hole 18, the method further includes: an isolation film (not shown) is formed on the substrate 10, and the isolation film (not shown) is located on the top surfaces of the second protective layer 17 and the first protective layer 12, and on the surface of the substrate 10 at the side wall and the bottom of the capacitor contact hole 18.

Specifically, an isolation film (not shown) is formed by adopting an atomic layer deposition mode, and the atomic layer deposition has the characteristics of low deposition rate, high compactness of a film layer formed by deposition, good step coverage rate and the like; thus, the isolation film (not shown) can be effectively isolated and protected with a small thickness, and the isolation film (not shown) can be prevented from occupying a small space between the adjacent bit line structures 15.

The isolation films (not shown) on the top surface of the second passivation layer 17, the top surface of the first passivation layer 12 and the surface of the substrate 10 are removed to form the isolation layer 30 on the sidewall of the capacitor contact hole 18.

In the process of removing the isolation film (not shown) on the surface of the substrate 10, a portion of the substrate 10 needs to be etched until the surface of the active region in the substrate 10 is exposed, so that the bottom of the subsequently formed conductive layer is connected to the active region.

It should be noted that, in the following drawings, the isolation layer 30 is only shown in the schematic cross-sectional view parallel to the bit line structure, in the specific three-dimensional structure diagram, in order that a person skilled in the art can visually see the difference of the top topography, the schematic structure of the isolation layer 30 is not shown, and the person skilled in the art should know that the isolation layer 30 should be included in the schematic three-dimensional structure diagram of the present invention.

Referring to fig. 10 to 14, fig. 10 to 12 are schematic cross-sectional views in a direction parallel to the extension direction of the bit line structure, fig. 13 is a schematic perspective view of the memory, fig. 14 is a schematic top view of the memory, the capacitor contact hole 18 is filled to form a conductive layer, the top surface of the conductive layer is flush with the top surface of the second passivation layer 17, and in a direction perpendicular to the bit line structure 15, the conductive layer further covers the top surface of the first passivation layer 12 exposed by the remaining second passivation layer 17, and the conductive layer is used for forming a capacitor contact structure subsequently.

In the embodiment, the conductive layer includes a first conductive layer 31 and a second conductive layer 33, the materials of the first conductive layer 31 and the second conductive layer 33 are different, the top surface of the second conductive layer 33 is flush with the top surface of the second passivation layer 17, and the second conductive layer 15 covers the top surface of the first passivation layer 12 in a direction perpendicular to the extension direction of the bit line structure 15.

The material of the first conductive layer 31 is a semiconductor conductive material, such as polysilicon; the top conductive material is a metal conductive material, such as a metal material with a relatively low resistivity, such as tungsten or silver. In addition, in the present embodiment, the conductive layer is illustrated as two layers, which does not limit the present embodiment, and in other embodiments, the conductive layer may have only a single-layer structure. The steps of forming the conductive layer are described below with reference to the accompanying drawings:

referring to fig. 10, a first conductive layer 31 is formed in the capacitor contact hole 18, and the height of the top surface of the first conductive layer 31 is lower than the height of the top surface of the first protective layer 12.

Referring to fig. 11, a top conductive film 32 is formed on the top surface of the first conductive layer 31, the top surface of the first protective layer 12, and the top surface of the second protective layer 17.

Specifically, in the present embodiment, the top conductive film 32 is formed by a spin coating process, and the top conductive film (not shown) formed by spin coating has an advantage of good filling property.

Referring to fig. 12, the top conductive film 32 is etched to form a second conductive layer 33.

In the present embodiment, the top conductive film 32 is etched to form the second conductive layer 33 by chemical mechanical polishing. The top surface of the top conductive film 32 is planarized by chemical mechanical polishing, which has a higher removal rate than an etching process and is beneficial to shortening the process cycle.

The schematic perspective structure of the memory formed at this time is shown in fig. 13, and the top view of the top profile thereof is shown in fig. 14.

Referring to fig. 8, the capacitor contact holes are arranged in a square for subsequent filling to form a capacitor contact structure, and the capacitor contact holes and the dielectric layer 16 are alternately arranged in a direction parallel to the extension direction of the bit line structure 15; in the direction perpendicular to the extension direction of the bit line structures 15, the capacitor contact holes and the bit line structures 15 are alternately arranged, and at this time, the capacitor contact holes are arranged in a square shape when viewed from the top of the memory. The capacitor contact holes and the lower electrodes of the capacitor are arranged in different ways, and usually a layer of staggered contact pads needs to be additionally formed to connect the lower electrode plate of the capacitor with the capacitor contact structure, so that the process is complex and the progress is slow.

In the embodiment of the present invention, the structure that the first protection layer 12 and the second protection layer 17 have a height difference is used to etch the formed capacitor contact structure, so as to change the arrangement manner of the top of the capacitor contact structure, referring to fig. 8 and 13, due to the height difference between the first protection layer 12 and the second protection layer 17, the formed conductive layer is used to fill the capacitor contact hole and the top surface of the first protection layer 12, and in the direction perpendicular to the extension direction of the bit line structure 15, the conductive layers adjacent to the capacitor contact hole are connected through the top surface of the first protection layer 12. Referring to fig. 17 in conjunction with the contact mask layer 40 formed in the predetermined direction in fig. 16, the top surface of the etched conductive layer 41 is flush with the top surface of the first protection layer 12, and the top surface of the unetched conductive layer 42 is flush with the second protection layer 17, with the contact mask layer 40 as a mask for etching the top topography of the capacitor contact structure. Compared with the prior art, the capacitor contact structure that originally arranges with bit line structure 15 in turn in the direction that perpendicular to bit line structure 15 extends this moment the top part is located the top surface of first protective layer 12, and it has certain contained angle to predetermine the direction and the direction that bit line structure 15 extends, thereby the mode of arranging at capacitor contact structure top has been changed, be close to more with the mode of arranging of the minimum hexagonal of follow-up electric capacity that needs to form, thereby optimize space utilization, make the electric capacity size of follow-up formation bigger, and, this process step of preparation dislocation contact electricity has still been saved, very big forming method of memory has been optimized.

Referring to fig. 15-17, fig. 15 is a schematic cross-sectional view in a direction parallel to the extension direction of the bit line structure, and fig. 16 and 17 are schematic top views of the memory device, in which a portion of the conductive layer 34 is etched to form separate capacitor contact structures.

Referring to fig. 15 and 16, a contact mask layer 40 is formed on the top surfaces of the conductive layer 34 and the second protection layer 17; the contact mask layer 40 exposes the conductive layer 34 and the second protective layer 17 with a preset width in a preset direction, and the contact mask layer 40 is alternately arranged with the exposed conductive layer 34 and the second protective layer 17 in a direction perpendicular to the preset direction; an included angle between the preset direction (refer to a dotted line 22 in fig. 17) and the extending direction of the bit line structure 15 is α, where α is greater than 0 ° and is not equal to 90 °, and the exposed conductive layer 34 is etched based on the preset direction until a part of the first protective layer 12 is exposed; and removing the contact mask layer 40, and using the residual conductive layer as the capacitor contact structure.

Specifically, the preset direction is a direction having a certain included angle α (α is greater than 0 ° and α is not equal to 90 °) with the extending direction of the bit line structure 15, the conductive layer 34 exposed by the contact mask layer 40 is etched until the first protection layer 12 is exposed, the contact mask layer 40 is removed, at this time, the height of the etched remaining conductive layer 41 (the dot filling portion in the figure) is consistent with the height of the first protection layer 12, and the height of the un-etched remaining conductive layer 42 is consistent with the height of the second protection layer 17.

At this time, when viewed from a top view, the position of the first protective layer 12 is exposed, and the etched remaining conductive layer 41 is not electrically connected to the unetched remaining conductive layer 42; and the etched remaining conductive layer 41 is electrically connected to the un-etched remaining conductive layer 42 at a position where the second protective layer 12 is not exposed. The conductive layers are separated from each other through the exposed position of the first protective layer 12 to form a discrete capacitor contact structure (the etched residual conductive layer 41 which is not separated by the first protective layer 12 and the unetched residual conductive layer 42), the original square arrangement mode of the top of the capacitor contact structure which is consistent with the capacitor contact hole is changed, the capacitor contact structure is directly connected with a capacitor lower electrode plate which is formed subsequently, the process step of manufacturing a staggered contact pad is omitted, and the forming method of the memory is greatly optimized.

In addition, referring to fig. 18 and 19, in this embodiment, after forming the discrete capacitive contact structure, the method further includes: the dielectric layer 16 is removed to form an air gap 50. By removing the dielectric layer 16 between the capacitor contact structures in a positioning manner on the first protective layer 12 and the second protective layer 17, an air gap is formed to reduce the dielectric constant between the capacitor contact structures, so that the parasitic capacitance between the capacitor contact structures is reduced, and the air gap is important for reducing the integration level of the memory.

Specifically, referring to fig. 18, an isolation mask layer (not shown) is formed on the top surface of the second protection layer 17, and based on the isolation mask layer (not shown), the second protection layer 17 on the top of the capacitor structures is patterned and removed in a direction parallel to the bit line structures 15, the dielectric layer 16 between the capacitor contact structures is exposed, the dielectric layer 16 between the capacitor contact structures is removed, and the air gap 50 is formed.

Referring to fig. 19, a sealing layer 51 is formed, the sealing layer 51 sealing the top of the air gap 50.

The sealing layer 51 is formed by adopting a rapid sealing process, the sealing layer 51 is used for sealing the air gap 50 to form an air gap isolation structure, the parasitic capacitance between the capacitor contact structures is greatly improved, and the structural performance of the formed memory is more excellent.

Specifically, the sealing layer 51 is formed by a fast sealing process, which has a fast deposition effect, and the formed sealing layer 51 is used for sealing the top of the air gap 50 to form an air isolation structure. In the present embodiment, the material of the sealing layer 51 is silicon nitride, and in other embodiments, the material of the sealing layer is an insulating semiconductor material, such as silicon oxynitride or silicon oxide.

In summary, in the embodiments of the present invention, by adjusting the process flow of the process of the memory, when the bit line stack is formed, the first protection layer is formed on the top of the bit line stack, and the second protection layer is formed on the top of the first protection layer in the subsequent process; the protective layer with staggered high and low levels is formed on the top of the bit line structure skillfully, which is beneficial to reducing the loss of the bit line structure in the etching process; and a top layer framework formed by protective layers with staggered high and low levels is utilized, and a connecting layer between the capacitor and the capacitor contact structure is ingeniously formed through one-step etching. The process flow of the manufacturing process of the memory at present is simplified, and further the production efficiency of the memory is improved and the production and operation cost of the memory is reduced.

The above steps are divided for clarity, and the implementation may be combined into one step or split some steps, and the steps are divided into multiple steps, so long as the steps include the same logical relationship, which is within the protection scope of the present patent; it is within the scope of the patent to add insignificant modifications to the flow or to introduce insignificant design, but not to change the core design of the flow.

A second embodiment of the present invention relates to a memory device, which can be formed by the above-described formation method.

Referring to fig. 2, 12 and 17, the memory provided in this embodiment will be described in detail below with reference to the drawings, and details of the same or corresponding portions as those in the first embodiment will not be repeated below.

A memory, comprising: a substrate 10, and a bit line structure 15 located on the substrate 10; a first protective layer 12 on a top surface of the bit line structure 15; the capacitor contact structures and the isolation structures are arranged between the bit line structures 15, and the capacitor contact structures and the isolation structures are alternately arranged in the extending direction of the bit line structures 15; a second passivation layer 17, disposed on the top surfaces of the first passivation layer 12 and the isolation structures between adjacent bit line structures 15, wherein the extending direction of the second passivation layer 17 is perpendicular to the extending direction of the bit line structures 15; the top of the capacitor contact structure has protrusions extending at intervals in a predetermined direction, the protrusions are further located on a portion of the top surface of the first passivation layer 12, an included angle between the predetermined direction and the extending direction of the bit line structure 15 is α, α is greater than 0 ° and is not equal to 90 °.

Specifically, the substrate 10 includes an array region and a peripheral region, and the substrate 10 includes embedded word lines, shallow trench isolation structures, active regions, and the like.

Referring to fig. 2, the bit line structure 15 includes a bit line contact layer 111 or a bottom substrate layer 112, a metal layer 113, and a top dielectric layer 114 sequentially stacked on the substrate 10; the bit line contact layer 111 is made of tungsten or polysilicon, the bottom dielectric layer 112 and the top dielectric layer 114 are made of silicon nitride, silicon dioxide or silicon oxynitride, and the metal layer 113 is made of one or more conductive materials, such as doped polysilicon, titanium nitride, a composite of tungsten and tungsten, etc.

The first protective layer 112 is used to protect the bit line structure from being etched in a subsequent etching process. In the present embodiment, the material of the first protection layer 112 is silicon oxynitride; in other embodiments, the material of the first protection layer is formed by using an insulating material, such as silicon nitride or silicon oxide.

It should be noted that, in the cross section of the same bit line structure, only one of the adjacent bit line structures 15 is connected to the active region in the substrate 10 through the bit line contact layer 111.

Accordingly, the isolation structure includes a dielectric layer or an air gap. Referring to fig. 12, in the present embodiment, the isolation structure between the capacitor contact structures is a dielectric layer 16. The material of the dielectric layer 16 is silicon oxide, and in other embodiments, the material of the dielectric layer 16 is formed by an insulating material, such as silicon nitride or silicon oxynitride.

A second protective layer 17 on the top surface of the first protective layer 12 and the isolation structures between adjacent bit line structures in a direction perpendicular to the extension direction of the bit line structures 15; in the present embodiment, the material of the second protective layer 17 is the same as that of the first protective layer 12; in other embodiments, the material of the second protection layer is formed by using an insulating material, such as silicon nitride or silicon oxide.

The top layer framework formed by the first protective layer 12 and the second protective layer 17 effectively improves the arrangement mode of the capacitor contact structure in the subsequent process of forming the capacitor contact structure, and is directly connected with a lower electrode plate of a capacitor to be formed subsequently, so that the formation process of the memory is effectively improved. It should be noted that, the thicknesses of the first protection layer 12 and the second protection layer 17 are not limited in the embodiments of the present invention, and the thicknesses of the first protection layer 12 and the second protection layer 17 may be set according to specific process requirements.

The capacitor contact structures and the isolation structures are arranged between the bit line structures 15, and the capacitor contact structures and the isolation structures are alternately arranged in the extending direction of the bit line structures; and along predetermineeing the direction, the capacitor contact structure has the arch, and the arch still is located partly the top surface of first protective layer, predetermineeing the direction and the direction contained angle that the bit line structure 15 extends and be alpha, alpha is greater than 0 and alpha is not equal to 90. Wherein the bottom of the capacitor contact structure is connected to the active region in the substrate 10.

Referring to fig. 17, in a top view, where the first passivation layer 12 is exposed, the etched remaining conductive layer 41 is not electrically connected to the un-etched remaining conductive layer 42 (i.e. the bump on the top of the capacitor contact structure); and the etched residual conductive layer 41 is electrically connected to the un-etched residual conductive layer 42 (i.e. the bump on the top of the capacitor contact structure) at the position where the second protection layer 12 is not exposed. The conductive layers are separated from each other through the exposed position of the first protective layer 12 to form a discrete capacitor contact structure (the etched residual conductive layer 41 and the unetched residual conductive layer 42 which are not separated by the first protective layer 12), the original square arrangement mode of the capacitor contact structure is changed, the capacitor contact structure is directly connected with a capacitor lower electrode plate formed subsequently, the process step of manufacturing staggered contact electricity is omitted, and the forming method of the memory is greatly improved.

In addition, referring to fig. 9, in other embodiments, the memory further includes an isolation layer on a sidewall of the isolation structure.

In addition, referring to fig. 19, in other embodiments, the isolation structure between the capacitive contact structures is an air gap.

Compared with the prior art, the top part of the formed capacitor contact structure is positioned on the top surface of the first protective layer, the arrangement mode of the original capacitor contact structure is changed, the connection between the subsequently formed capacitor and the capacitor contact structure becomes simple, the process flow of the manufacturing procedure process of the current memory is improved, the production efficiency of the memory is improved, and the production and operation cost of the memory is reduced.

Since the first embodiment corresponds to the present embodiment, the present embodiment can be implemented in cooperation with the first embodiment. The related technical details mentioned in the first embodiment are still valid in this embodiment, and the technical effects that can be achieved in the first embodiment can also be achieved in this embodiment, and are not described herein again in order to reduce repetition. Accordingly, the related-art details mentioned in the present embodiment can also be applied to the first embodiment.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific embodiments for practicing the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.