阅读说明：本技术 半导体结构及其形成方法 (Semiconductor structure and forming method thereof ) 是由 王楠 于 2020-05-13 设计创作，主要内容包括：一种半导体结构及其形成方法,包括：提供衬底；在所述衬底上形成隔离结构；在所述隔离结构上形成栅极结构；在所述栅极结构内形成第一开口；在所述第一开口内形成第一导电结构,所述第一导电结构的侧壁表面与所述栅极结构的栅极层相接触。通过所述第一导电结构的侧壁表面与所述栅极结构的栅极层相接触,以此增大了所述第一导电结构和所述栅极结构之间的接触面积,减小所述第一导电结构和所述栅极结构之间的接触电阻,进而提升最终形成的半导体结构的电学性能。(A semiconductor structure and a method of forming the same, comprising: providing a substrate; forming an isolation structure on the substrate; forming a gate structure on the isolation structure; forming a first opening in the gate structure; and forming a first conductive structure in the first opening, wherein the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure. The side wall surface of the first conductive structure is in contact with the grid layer of the grid structure, so that the contact area between the first conductive structure and the grid structure is increased, the contact resistance between the first conductive structure and the grid structure is reduced, and the electrical performance of the finally formed semiconductor structure is improved.)

1. A semiconductor structure, comprising:

a substrate;

an isolation structure on the substrate;

a gate structure located on the isolation structure;

a first opening located within the gate structure;

and the first conductive structure is positioned in the first opening, and the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure.

2. The semiconductor structure of claim 1, wherein the first opening exposes a top surface of the isolation structure.

3. The semiconductor structure of claim 1, further comprising: a plurality of mutually discrete fin portions on the substrate; the isolation structure covers a part of the side wall of the fin part, and the top surface of the isolation structure is lower than that of the fin part; the gate structure crosses over the fin portion, and the gate structure covers a portion of a sidewall and a top surface of the fin portion.

4. The semiconductor structure of claim 3, further comprising: the source-drain doping layers are positioned in the fin parts on two sides of the grid structure; the second conductive structure is positioned on the source drain doping layer, and the top surface of the second conductive structure is higher than that of the gate structure; the first dielectric layer is positioned on the isolation structure, covers the grid structure and the source-drain doping layer and is exposed out of the top surface of the grid structure; and the second dielectric layer is positioned on the first dielectric layer and the grid structure.

5. The semiconductor structure of claim 1, wherein the gate structure further comprises: the semiconductor device comprises a gate dielectric layer, a protective layer and a side wall, wherein the gate layer is positioned on the gate dielectric layer, the protective layer is positioned on the gate layer, and the side wall is positioned on the side walls of the gate layer and the protective layer; the second conductive structure is located on a part of the surface of the protective layer, and the second conductive structure is in contact with the side wall.

6. The semiconductor structure of claim 5, wherein the gate dielectric layer comprises a high-K dielectric material; the material of the protective layer comprises silicon nitride; the material of the side wall comprises one or more of silicon nitride, silicon oxide and silicon oxynitride.

7. The semiconductor structure of claim 4, wherein the first conductive structure is located within the second dielectric layer and the gate structure, the second conductive structure is located within the first dielectric layer and the second dielectric layer, and the second dielectric layer exposes a top surface of the first conductive structure and the second conductive structure.

8. The semiconductor structure of claim 1, wherein a material of the first conductive structure comprises a metal comprising tungsten.

9. The semiconductor structure of claim 4, wherein a material of the second conductive structure comprises a metal comprising tungsten.

10. A method of forming a semiconductor structure, comprising:

providing a substrate;

forming an isolation structure on the substrate;

forming a gate structure on the isolation structure;

forming a first opening in the gate structure;

and forming a first conductive structure in the first opening, wherein the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure.

11. The method of forming a semiconductor structure of claim 10, wherein the first opening exposes a top surface of the isolation structure.

12. The method of forming a semiconductor structure of claim 10, further comprising: forming a plurality of mutually discrete fin parts on the substrate; the isolation structure covers a part of the side wall of the fin part, and the top surface of the isolation structure is lower than that of the fin part; the gate structure crosses over the fin portion, and the gate structure covers a portion of a sidewall and a top surface of the fin portion.

13. The method of forming a semiconductor structure of claim 12, further comprising: forming source-drain doped layers in the fin parts on the two sides of the grid structure; forming a first dielectric layer on the isolation structure, wherein the first dielectric layer covers the source-drain doping layer and the grid structure, and the first dielectric layer is exposed out of the top surface of the grid structure; forming a second dielectric layer on the first dielectric layer and the grid structure; and forming a second conductive structure on the source-drain doped layer.

14. The method of forming a semiconductor structure of claim 13, wherein the method of forming the first conductive structure and the second conductive structure comprises: forming a second opening in the second dielectric layer and the first dielectric layer, wherein the second opening exposes the top surface of the source-drain doped layer; forming a third opening in the second dielectric layer, wherein the first opening is exposed out of the third opening; forming the initial conductive structure in the first opening, the second opening, the third opening and the second dielectric layer; carrying out planarization treatment on the initial conductive structure until the top surface of the second dielectric layer is exposed, and forming the first conductive structure in the first opening and the third opening; and forming the second conductive structure in the second opening.

15. The method of forming a semiconductor structure of claim 14, wherein the process of planarizing the initial conductive structure comprises a chemical mechanical polish process.

16. The method of forming a semiconductor structure of claim 14, wherein the method of forming the first opening, the second opening, and the third opening comprises: etching the grid structure until the top surface of the isolation structure is exposed, and forming the first opening in the grid structure; forming a second dielectric layer in the first opening and on the gate structure and the first dielectric layer; forming a patterning layer on the second dielectric layer, wherein the patterning layer is provided with a patterning opening which exposes a part of the top surface of the second dielectric layer; and etching the second dielectric layer and the first dielectric layer by using the patterned layer as a mask until the source-drain doping layer and the top surface of the isolation structure are exposed, forming a second opening in the first dielectric layer and the second dielectric layer, forming a third opening in the second dielectric layer, and exposing the first opening through the third opening.

17. The method of forming a semiconductor structure of claim 16, wherein the patterning layer comprises: forming an initial patterning layer on the second dielectric layer; forming a photoresist layer on the initial patterning layer; exposing the photoresist layer by adopting an extreme ultraviolet light source, and forming a photoresist opening exposing a part of the initial patterning layer on the photoresist layer; and etching the initial patterning layer by taking the photoresist layer as a mask to form the patterning layer.

18. The method of forming a semiconductor structure of claim 17, wherein the gate structure further comprises: the semiconductor device comprises a gate dielectric layer, a protective layer and a side wall, wherein the gate layer is positioned on the gate dielectric layer, the protective layer is positioned on the gate layer, and the side wall is positioned on the side walls of the gate layer and the protective layer; the second conductive structure is located on a part of the surface of the protective layer, and the second conductive structure is in contact with the side wall.

19. The semiconductor structure of claim 18, wherein the gate dielectric layer comprises a high-K dielectric material; the material of the protective layer comprises silicon nitride; the material of the side wall comprises one or more of silicon nitride, silicon oxide and silicon oxynitride.

20. The method of forming a semiconductor structure of claim 10, wherein the material of the first conductive structure comprises a metal comprising tungsten.

21. The method of forming a semiconductor structure of claim 13, wherein the material of the second conductive structure comprises a metal comprising tungsten.

Technical Field

The present invention relates to the field of semiconductor manufacturing technologies, and in particular, to a semiconductor structure and a method for forming the same.

Background

With the rapid development of semiconductor manufacturing technology, semiconductor devices are being developed toward higher element density and higher integration. As the transistor is currently widely used as the most basic semiconductor device, as the element density and the integration degree of the semiconductor device are improved, the gate size of the planar transistor is shorter and shorter, and the conventional planar transistor has weak control capability on channel current, generates a short channel effect, generates leakage current, and finally affects the electrical performance of the semiconductor device.

In order to overcome the short channel effect of the transistor and suppress the leakage current, a Fin field effect transistor (Fin FET) is proposed in the prior art, and the Fin FET is a common multi-gate device.

The structure of the prior fin field effect transistor comprises: a fin portion on the substrate; the dielectric layer is positioned on the surface of the substrate and covers part of the side wall of the fin part; the grid electrode structure stretches across the fin part and the dielectric layer and covers part of the side wall of the fin part and the top surface of the fin part; and the source region and the drain region are positioned in the fin parts at two sides of the grid structure. The gate structure includes: the gate dielectric layer is positioned on the surface of the dielectric layer, part of side walls and the bottom surface of the fin portion, the gate layer is positioned on the surface of the gate dielectric layer, and the side walls are positioned on the surfaces of the gate layer and the side walls of the gate dielectric layer. In order to enable the fin field effect transistor to form a chip circuit with other semiconductor devices on a substrate, a conductive structure, such as a conductive plug or an electrical interconnection line, needs to be formed on the surface of one or more of a source region, a drain region and a gate layer of the fin field effect transistor.

However, the performance of the semiconductor structure formed in the prior art still needs to be improved.

Disclosure of Invention

The invention provides a semiconductor structure and a forming method thereof, which can effectively improve the performance of the finally formed semiconductor structure.

To solve the above problems, the present invention provides a semiconductor structure, comprising: a substrate; an isolation structure on the substrate; a gate structure located on the isolation structure; a first opening located within the gate structure; and the first conductive structure is positioned in the first opening, and the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure.

Optionally, the first opening exposes a top surface of the isolation structure.

Optionally, the method further includes: a plurality of mutually discrete fin portions on the substrate; the isolation structure covers a part of the side wall of the fin part, and the top surface of the isolation structure is lower than that of the fin part; the gate structure crosses over the fin portion, and the gate structure covers a portion of a sidewall and a top surface of the fin portion.

Optionally, the method further includes: the source-drain doping layers are positioned in the fin parts on two sides of the grid structure; the second conductive structure is positioned on the source drain doping layer, and the top surface of the second conductive structure is higher than that of the gate structure; the first dielectric layer is positioned on the isolation structure, covers the grid structure and the source-drain doping layer and is exposed out of the top surface of the grid structure; and the second dielectric layer is positioned on the first dielectric layer and the grid structure.

Optionally, the gate structure further includes: the semiconductor device comprises a gate dielectric layer, a protective layer and a side wall, wherein the gate layer is positioned on the gate dielectric layer, the protective layer is positioned on the gate layer, and the side wall is positioned on the side walls of the gate layer and the protective layer; the second conductive structure is located on a part of the surface of the protective layer, and the second conductive structure is in contact with the side wall.

Optionally, the gate dielectric layer is made of a high-K dielectric material; the material of the protective layer comprises silicon nitride; the material of the side wall comprises one or more of silicon nitride, silicon oxide and silicon oxynitride.

Optionally, the first conductive structure is located in the second dielectric layer and the gate structure, the second conductive structure is located in the first dielectric layer and the second dielectric layer, and the second dielectric layer exposes the top surfaces of the first conductive structure and the second conductive structure.

Optionally, the material of the first conductive structure includes a metal, and the metal includes tungsten.

Optionally, the material of the second conductive structure includes a metal, and the metal includes tungsten.

Correspondingly, the invention also provides a method for forming the semiconductor structure, which comprises the following steps: providing a substrate; forming an isolation structure on the substrate; forming a gate structure on the isolation structure; forming a first opening in the gate structure, wherein the first opening exposes a top surface of the isolation structure; and forming a first conductive structure in the first opening, wherein the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure.

Optionally, the first opening exposes a top surface of the isolation structure.

Optionally, the method further includes: forming a plurality of mutually discrete fin parts on the substrate; the isolation structure covers a part of the side wall of the fin part, and the top surface of the isolation structure is lower than that of the fin part; the gate structure crosses over the fin portion, and the gate structure covers a portion of a sidewall and a top surface of the fin portion.

Optionally, the method further includes: forming source-drain doped layers in the fin parts on the two sides of the grid structure; forming a first dielectric layer on the isolation structure, wherein the first dielectric layer covers the source-drain doping layer and the grid structure, and the first dielectric layer is exposed out of the top surface of the grid structure; forming a second dielectric layer on the first dielectric layer and the grid structure; and forming a second conductive structure on the source-drain doped layer.

Optionally, the method for forming the first conductive structure and the second conductive structure includes: forming a second opening in the second dielectric layer and the first dielectric layer, wherein the second opening exposes the top surface of the source-drain doped layer; forming a third opening in the second dielectric layer, wherein the first opening is exposed out of the third opening; forming the initial conductive structure in the first opening, the second opening, the third opening and the second dielectric layer; carrying out planarization treatment on the initial conductive structure until the top surface of the second dielectric layer is exposed, and forming the first conductive structure in the first opening and the third opening; and forming the second conductive structure in the second opening.

Optionally, the process of planarizing the initial conductive structure includes a chemical mechanical polishing process.

Optionally, the method for forming the first opening, the second opening, and the third opening includes: etching the grid structure until the top surface of the isolation structure is exposed, and forming the first opening in the grid structure; forming a second dielectric layer in the first opening and on the gate structure and the first dielectric layer; forming a patterning layer on the second dielectric layer, wherein the patterning layer is provided with a patterning opening which exposes a part of the top surface of the second dielectric layer; and etching the second dielectric layer and the first dielectric layer by using the patterned layer as a mask until the source-drain doping layer and the top surface of the isolation structure are exposed, forming a second opening in the first dielectric layer and the second dielectric layer, forming a third opening in the second dielectric layer, and exposing the first opening through the third opening.

Optionally, the forming method of the patterned layer includes: forming an initial patterning layer on the second dielectric layer; forming a photoresist layer on the initial patterning layer; exposing the photoresist layer by adopting an extreme ultraviolet light source, and forming a photoresist opening exposing a part of the initial patterning layer on the photoresist layer; and etching the initial patterning layer by taking the photoresist layer as a mask to form the patterning layer.

Optionally, the gate structure further includes: the semiconductor device comprises a gate dielectric layer, a protective layer and a side wall, wherein the gate layer is positioned on the gate dielectric layer, the protective layer is positioned on the gate layer, and the side wall is positioned on the side walls of the gate layer and the protective layer; the second conductive structure is located on a part of the surface of the protective layer, and the second conductive structure is in contact with the side wall.

Optionally, the gate dielectric layer is made of a high-K dielectric material; the material of the protective layer comprises silicon nitride; the material of the side wall comprises one or more of silicon nitride, silicon oxide and silicon oxynitride.

Optionally, the material of the first conductive structure includes a metal, and the metal includes tungsten.

Optionally, the material of the second conductive structure includes a metal, and the metal includes tungsten.

Compared with the prior art, the technical scheme of the invention has the following advantages:

in the structure of the technical scheme of the invention, the first conductive structure is positioned in the first opening, and the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure, so that the contact area between the first conductive structure and the grid structure is increased, the contact resistance between the first conductive structure and the grid structure is reduced, and the electrical property of the finally formed semiconductor structure is further improved.

Further, the first opening exposes the top surface of the isolation structure, so that the sidewall surface of the first conductive structure is maximally formed to be in contact with the gate structure, and the contact resistance between the first conductive structure and the gate structure is maximally reduced.

In the forming method of the technical scheme, the first conductive structure is formed in the first opening, and the side wall surface of the first conductive structure is in contact with the grid layer of the grid structure, so that the contact area between the first conductive structure and the grid structure is increased, the contact resistance between the first conductive structure and the grid structure is reduced, and the electrical performance of the finally formed semiconductor structure is improved.

Further, the first opening exposes the top surface of the isolation structure, so that the sidewall surface of the first conductive structure is maximally formed to be in contact with the gate structure, and the contact resistance between the first conductive structure and the gate structure is maximally reduced.

Further, the method for forming the patterning layer comprises the following steps: forming an initial patterning layer on the second dielectric layer; forming a photoresist layer on the initial patterning layer; exposing the photoresist layer by adopting an extreme ultraviolet light source, and forming a photoresist opening exposing a part of the initial patterning layer on the photoresist layer; and etching the initial patterning layer by taking the photoresist layer as a mask to form the patterning layer. In the technical scheme of the invention, exposure treatment is carried out by an extreme ultraviolet light source, and the photoresist openings corresponding to the second opening and the third opening are simultaneously formed on the photoresist layer by utilizing the primary photomask, so that the photomask is effectively saved, the processing steps are simplified, and the manufacturing cost is reduced.

Drawings

Fig. 1-2 are schematic structural diagrams of a semiconductor structure;

fig. 3 to 13 are schematic structural diagrams of steps of a method for forming a semiconductor structure according to an embodiment of the present invention.

Detailed Description

As described in the background, the performance of semiconductor structures formed in the prior art is still to be improved. The following detailed description will be made in conjunction with the accompanying drawings.

Referring to fig. 1 and 2, fig. 2 is a schematic cross-sectional view taken along line a-a of fig. 1, providing a substrate 100; forming an isolation structure 101 on the substrate 100; forming a gate structure on the isolation structure 101, where the gate structure includes a gate dielectric layer 102, a gate layer 103 located on the gate dielectric layer 102, a protection layer 104 located on the gate layer 103, and a sidewall spacer 105 located on sidewalls of the gate layer 103 and the protection layer 104; forming a first opening (not labeled) in the gate structure, the first opening exposing a top surface of the gate layer 103; a first conductive structure 106 is formed within the first opening.

In this embodiment, the first conductive structure 106 is formed on the gate structure, so as to electrically interconnect the gate structure and other device structures, thereby implementing the electrical function of the semiconductor structure. However, as the feature size of the semiconductor device is smaller, in the embodiment, only the bottom surface of the first conductive structure 106 is connected to the gate layer 103, so that the contact area between the first conductive structure 106 and the gate structure is smaller, and the contact resistance between the first conductive structure 106 and the gate structure is larger, which may affect the electrical performance of the finally formed semiconductor structure.

On the basis, the invention provides a semiconductor structure and a forming method thereof, wherein a first conductive structure is formed in the first opening, and the side wall surface of the first conductive structure is contacted with the grid layer of the grid structure, so that the contact area between the first conductive structure and the grid structure is increased, the contact resistance between the first conductive structure and the grid structure is reduced, and the electrical property of the finally formed semiconductor structure is improved.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Fig. 3 to fig. 13 are schematic structural diagrams illustrating a process of forming a semiconductor structure according to an embodiment of the present invention.

Referring to fig. 3, a substrate 200 is provided.

In this embodiment, the material of the substrate 200 is monocrystalline silicon. In other embodiments, the material of the substrate can also be polysilicon or amorphous silicon; the substrate can also be made of semiconductor materials such as germanium, silicon germanium, gallium arsenide and the like.

With continued reference to fig. 3, a plurality of mutually discrete fins 201 are formed on the substrate 200.

In this embodiment, the method for forming the substrate 200 and the fin 201 includes: providing an initial substrate (not shown) on which a first patterned layer is formed; and etching the initial substrate by taking the first patterning layer as a mask to form the substrate 200 and the fin part 201.

In this embodiment, the material of the fin 201 is monocrystalline silicon. In other embodiments, the material of the fin may also be single crystal silicon germanium or other semiconductor materials.

In other embodiments, the substrate may not form the structure of the fin portion.

Referring to fig. 4, an isolation structure 202 is formed on the substrate 200.

In the present embodiment, the isolation structure 202 covers a portion of the sidewall of the fin 201, and a top surface of the isolation structure 202 is lower than a top surface of the fin 201.

The method for forming the isolation structure 202 comprises the following steps: forming an initial isolation structure (not shown) on the substrate 200, the initial isolation structure covering the fin 201; planarizing the initial isolation structure until the top surface of the fin 201 is exposed; after the planarization process, a portion of the initial isolation structure is removed to form the isolation structure 202, wherein a top surface of the isolation structure 202 is lower than a top surface of the fin 201.

In this embodiment, a wet etching process is used for the planarization process of the initial isolation structure; in other embodiments, the process of planarizing the initial isolation structure may further include a dry etching process or a chemical mechanical polishing process (CMP).

In the present embodiment, the material of the isolation structure 202 includes silicon oxide; in other embodiments, the material of the isolation structure may further include silicon nitride or silicon oxynitride.

Referring to fig. 5 and 6, fig. 6 is a schematic cross-sectional view taken along line B-B in fig. 5, wherein a gate structure is formed on the isolation structure 202.

In this embodiment, the gate structure crosses over the fin 201, and the gate structure covers a portion of the sidewalls and the top surface of the fin 201.

In this embodiment, the gate structure includes: the semiconductor structure comprises a gate dielectric layer 203, a gate layer 204, a protective layer 205 and a sidewall spacer 206, wherein the gate layer 204 is located on the gate dielectric layer 203, the protective layer 205 is located on the gate layer 204, and the sidewall spacer 206 is located on the sidewalls of the gate layer 204 and the protective layer 205.

In this embodiment, the material of the gate dielectric layer 203 includes a high-K dielectric material.

The material of the gate layer 204 includes a metal, which includes: tungsten, aluminum, copper, titanium, silver, gold, lead, or nickel. In this embodiment, the material of the gate layer 204 is tungsten.

The material of the sidewall spacers 206 includes one or more of silicon nitride, silicon oxide and silicon oxynitride. In this embodiment, the sidewall spacers 206 are made of silicon nitride.

In this embodiment, the material of the protection layer 205 is silicon nitride.

With continuing reference to fig. 5 and fig. 6, in the present embodiment, a source-drain doping layer 207 is formed in the fin 201 on both sides of the gate structure; a first dielectric layer 208 is formed on the isolation structure 202, the first dielectric layer 208 covers the source-drain doping layer 207 and the gate structure, and the first dielectric layer 208 exposes the top surface of the gate structure.

In this embodiment, the method for forming the first dielectric layer 208, the gate structure, and the source-drain doping layer 207 includes: forming a gate dielectric layer 203 on the isolation structure 202; forming a dummy gate layer (not shown) on the gate dielectric layer 203; forming the side wall 206 on the surface of the side wall of the pseudo gate layer; etching the fin portion 201 by using the dummy gate layer and the side walls 206 as masks, and forming source and drain openings (not marked) in the fin portion 201; forming a source-drain doping layer 207 in the source-drain opening; forming an initial dielectric layer (not shown) on the isolation structure 202, wherein the initial dielectric layer covers the dummy gate layer, the sidewall spacers 206 and the source-drain doping layer 207; planarizing the initial dielectric layer until the dummy gate layer is exposed, and forming the first dielectric layer 208; after the first dielectric layer 208 is formed, the dummy gate layer is removed to form an opening (not labeled); forming the gate layer 204 on the bottom surface of the opening; etching to remove a portion of the gate layer 204, and forming a gate opening (not labeled) on the gate layer 204; the protection layer 205 is formed within the gate opening.

In this embodiment, the first dielectric layer 208 is made of silicon oxide; in other embodiments, the material of the first dielectric layer may also be a low-k dielectric material (low-k dielectric material refers to a dielectric material with a relative dielectric constant lower than 3.9) or an ultra-low-k dielectric material (ultra-low-k dielectric material refers to a dielectric material with a relative dielectric constant lower than 2.5).

Referring to fig. 7, the views of fig. 7 and fig. 6 are in the same direction, and a first opening 209 is formed in the gate structure.

In the present embodiment, the first opening 209 exposes the top surface of the isolation structure 202.

In a subsequent process, a first conductive structure needs to be formed in the first opening 209, and since the first opening 209 exposes the top surface of the isolation structure 202, the formed first conductive structure maximally makes contact with the gate structure, thereby maximally reducing a contact resistance between the first conductive structure and the gate structure.

In this embodiment, the method for forming the first opening 209 includes: forming a second patterned layer (not shown) on the gate structure, the second patterned layer exposing a portion of a top surface of the gate structure; and etching the gate structure by using the second patterning layer as a mask until the top surface of the isolation structure 202 is exposed, and forming the first opening 209 in the gate structure.

In this embodiment, the gate structure is etched by a dry etching process, and the etching gas for the dry etching is SF₆And CH₄(ii) a In other embodiments, the etching gas for the dry etching may also be HB₂And CH₄。

Referring to fig. 8, after forming the first opening 209, a second dielectric layer 210 is formed on the first dielectric layer 208 and the gate structure.

In this embodiment, the second dielectric layer 210 fills the first opening 209.

In this embodiment, the second dielectric layer 210 is made of silicon oxide; in other embodiments, the material of the second dielectric layer may also be a low-k dielectric material (low-k dielectric material refers to a dielectric material with a relative dielectric constant lower than 3.9) or an ultra-low-k dielectric material (ultra-low-k dielectric material refers to a dielectric material with a relative dielectric constant lower than 2.5).

Forming a first conductive structure in the first opening 209 after forming the second dielectric layer 210, wherein a sidewall surface of the first conductive structure is in contact with a gate layer of the gate structure; and forming a second conductive structure on the source-drain doping layer 207. Please refer to fig. 9 to 13 for a specific process of forming the first conductive structure and the second conductive structure.

Referring to fig. 9, 10 and 11, fig. 10 is a schematic cross-sectional view taken along line C-C in fig. 9, and fig. 11 is a schematic cross-sectional view taken along line D-D in fig. 9, a patterned layer 211 is formed on the second dielectric layer 210, and the patterned layer 211 has a patterned opening (not labeled) thereon for exposing a portion of the top surface of the second dielectric layer 210; and etching the second dielectric layer 210 and the first dielectric layer 208 by using the patterned layer 211 as a mask until the source-drain doping layer 207 and the top surface of the isolation structure 202 are exposed, forming the second opening 212 in the first dielectric layer 208 and the second dielectric layer 210, exposing the top surface of the source-drain doping layer 207 through the second opening 212, forming the third opening 213 in the second dielectric layer 210, and exposing the first opening 209 through the third opening 213.

In this embodiment, the method for forming the patterned layer 211 includes: forming an initial patterning layer (not shown) on the second dielectric layer 210; forming a photoresist layer (not shown) on the initial patterning layer; exposing the photoresist layer by adopting an extreme ultraviolet light source, and forming a photoresist opening exposing a part of the initial patterning layer on the photoresist layer; and etching the initial patterning layer by using the photoresist layer as a mask to form the patterning layer 211.

In the prior art, the second opening 212 and the third opening 213 need to be formed by two photo-mask respectively, in the technical scheme of the invention, exposure treatment is performed by an extreme ultraviolet light source, and the photo-resist openings corresponding to the second opening 212 and the third opening 213 are formed on the photo-resist layer by using one photo-mask, so that the photo-mask can be effectively saved, the process steps are simplified, and the manufacturing cost is reduced.

Referring to fig. 12 and 13, the view directions of fig. 12 and 10 are the same, and the view directions of fig. 13 and 11 are the same, the initial conductive structure (not shown) is formed in the first opening 209, the second opening 212, the third opening 213, and the second dielectric layer 210; planarizing the initial conductive structure until the top surface of the second dielectric layer 210 is exposed, and forming the first conductive structure 214 in the first opening 209 and the third opening 213; the second conductive structure 215 is formed within the second opening 212.

By forming the first conductive structure 214 in the first opening 209 and contacting the sidewall surface of the first conductive structure 214 with the gate layer 204 of the gate structure, the contact area between the first conductive structure 214 and the gate structure is increased, the contact resistance between the first conductive structure 214 and the gate structure is reduced, and thus the electrical performance of the finally formed semiconductor structure is improved.

In this embodiment, the second conductive structure 215 is located on a portion of the surface of the protection layer 205, and the second conductive structure 215 is in contact with the sidewall 206.

In this embodiment, the process of planarizing the initial conductive structure employs a Chemical Mechanical Polishing (CMP) process.

In this embodiment, the material of the first conductive structure 214 includes a metal, and the metal is tungsten.

In this embodiment, the material of the second conductive structure 215 includes a metal, and the metal is tungsten.

Accordingly, the present invention further provides a semiconductor structure, with reference to fig. 12 and 13, including: a substrate 200; an isolation structure 202 located on the substrate 200; a gate structure located on the isolation structure 202; a first opening 209 within the gate structure; a first conductive structure 214 located within the first opening 209, a sidewall surface of the first conductive structure 214 being in contact with the gate layer 204 of the gate structure.

By the first conductive structure 214 located in the first opening 209, and the sidewall surface of the first conductive structure 214 is in contact with the gate layer 204 of the gate structure, the contact area between the first conductive structure 214 and the gate structure is increased, the contact resistance between the first conductive structure 214 and the gate structure is reduced, and thus the electrical performance of the finally formed semiconductor structure is improved.

In the present embodiment, the first opening 209 exposes the top surface of the isolation structure 202. Since the first opening 209 exposes the top surface of the isolation structure 202, the sidewall surface of the first conductive structure 214 is formed to maximally contact the gate structure, thereby maximally reducing the contact resistance between the first conductive structure 214 and the gate structure.

In this embodiment, the method further includes: a plurality of mutually discrete fin portions 201 on the substrate 200; the isolation structure 202 covers a part of the sidewall of the fin 201, and the top surface of the isolation structure 202 is lower than the top surface of the fin 201; the gate structure spans the fin 201 and covers a portion of the sidewalls and top surface of the fin 201.

In this embodiment, the method further includes: the source-drain doping layers 207 are positioned on two sides of the gate structure in the fin portion 201; a second conductive structure 215 located on the source-drain doping layer 207, wherein a top surface of the second conductive structure 215 is higher than a top surface of the gate structure; a first dielectric layer 208 located on the isolation structure 202, wherein the first dielectric layer 208 covers the gate structure and the source-drain doping layer 207, and the first dielectric layer 208 exposes the top surface of the gate structure; a second dielectric layer 210 over the first dielectric layer 208 and the gate structure.

In this embodiment, the gate structure further includes: the semiconductor structure comprises a gate dielectric layer 203, a protective layer 205 and a sidewall spacer 206, wherein the gate layer 204 is positioned on the gate dielectric layer 203, the protective layer 205 is positioned on the gate layer 204, and the sidewall spacer 206 is positioned on the sidewalls of the gate layer 204 and the protective layer 205; the second conductive structure 215 is located on a portion of the surface of the protection layer 205, and the second conductive structure 215 is in contact with the sidewall 206.

In this embodiment, the material of the gate dielectric layer 203 includes a high-K dielectric material.

In the present embodiment, the material of the protection layer 205 includes silicon nitride.

In this embodiment, the sidewall spacers 206 are made of silicon nitride; in other embodiments, the material of the sidewall may also be one or a combination of more than one of the silicon oxide and the silicon oxynitride.

In this embodiment, the first conductive structure 214 is located in the second dielectric layer 210 and the gate structure, the second conductive structure 215 is located in the first dielectric layer 208 and the second dielectric layer 210, and the second dielectric layer 210 exposes the top surfaces of the first conductive structure 214 and the second conductive structure 215.

In the present embodiment, the material of the first conductive structure 214 includes a metal, and the metal includes tungsten.

In the present embodiment, the material of the second conductive structure 215 includes a metal, and the metal includes tungsten.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.