Patent Publication Number: US-2022223603-A1

Title: Method of manufacturing semiconductor structure and semiconductor structure

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/CN2021/111383, filed on Aug. 9, 2021, which claims the priority to Chinese Patent Application 202110050700.1, titled “METHOD OF MANUFACTURING SEMICONDUCTOR STRUCTURE AND SEMICONDUCTOR STRUCTURE” and filed on Jan. 14, 2021. The entire contents of International Application No. PCT/CN2021/111383 and Chinese Patent Application 202110050700.1 are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to, but is not limited to, a method of manufacturing a semiconductor structure and a semiconductor structure. 
     BACKGROUND 
     The semiconductor structure as a memory is used to store programs and various data information. Random access memory (RAM) is divided into static random access memory (SRAM) and dynamic random access memory (DRAM). The dynamic random access memory usually includes a capacitor and a transistor connected to the capacitor. The capacitor is configured to store charges representing storage information. The transistor is a switch that controls inflow and release of the charges from the capacitor. During data writing, a word line provides a high level, the transistor is turned on, and a bit line charges the capacitor. During data reading, the word line also provides a high level, the transistor is turned on, and the capacitor is discharged, so that the bit line obtains a readout signal. 
     However, as the process node of the semiconductor structure is reduced continuously, the performance of the semiconductor needs to be further improved. 
     SUMMARY 
     An overview of the subject matter detailed in the present disclosure is provided below, which is not intended to limit the protection scope of the claims. 
     Embodiments of the present disclosure provide a method of manufacturing a semiconductor structure and a semiconductor structure. 
     According to a first aspect, the embodiments of the present disclosure provide a method of manufacturing a semiconductor structure, including: providing a base; and forming an electrical contact layer, a bottom barrier layer, and a conductive layer that are sequentially stacked on the base, a material of the conductive layer including molybdenum. 
     According to a second aspect, the embodiments of the present disclosure provide a semiconductor structure, including: a base; an electrical contact layer located on the base; a bottom barrier layer located on the electrical contact layer; and a conductive layer located on the bottom barrier layer, a material of the conductive layer including molybdenum. 
     Other aspects of the present disclosure are understandable upon reading and understanding of the drawings and detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings incorporated into the specification and constituting part of the specification illustrate the embodiments of the present disclosure, and are used together with the description to explain the principles of the embodiments of the present disclosure. In these drawings, similar reference numerals are used to represent similar elements. The drawings in the following description are part rather than all of the embodiments of the present disclosure. Those skilled in the art may derive other drawings based on these drawings without creative efforts. 
         FIG. 1  to  FIG. 6  are schematic structural diagrams corresponding to various steps of a method of manufacturing a semiconductor structure according to a first embodiment of the present disclosure; and 
         FIG. 7  to  FIG. 10  are schematic structural diagrams corresponding to various steps of a method of manufacturing a semiconductor structure according to a second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The technical solutions in the embodiments of the present disclosure are described below clearly and completely with reference to the drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative efforts should fall within the protection scope of the present disclosure. It should be noted that the embodiments in the present disclosure and features in the embodiments may be combined with each other in a non-conflicting manner. 
     As mentioned in the background, the performance of the semiconductor structure in the prior art needs to be improved. Upon analysis, the main reasons are as follows: the resistance of the conductive layer in the semiconductor structure is closely related to the performance of the semiconductor structure; high resistance of the conductive layer leads to poor conductivity of the semiconductor structure. Tungsten is used as the material of the conductive layer in the semiconductor structure, but it becomes increasingly difficult for the resistance of tungsten to meet the requirement of low resistance. The conductive layer made of tungsten easily reacts with the electrical contact layer; therefore, a thicker barrier layer is needed between the electrical contact layer and the conductive layer. In the case of the same volume of the semiconductor structure, the barrier layer occupies a larger space, and the conductive layer occupies a smaller space. Since the resistance of the barrier layer is greater than the resistance of the conductive layer, the semiconductor structure has high total resistance. The step of forming the conductive layer includes an etching process. As the tungsten is easily etched, the side surface of the conductive layer tends to have a depressed shape, resulting in a smaller volume of the conductive layer, which will further increase the resistance of the conductive layer, thus reducing the conductivity of the semiconductor structure. 
     The embodiments of the present disclosure provide a method of manufacturing a semiconductor structure, including: forming a bottom barrier layer located on an electrical contact layer, and forming a conductive layer located on the bottom barrier layer, a material of the conductive layer including molybdenum. Molybdenum has lower resistance than tungsten, and can reduce the resistance of the conductive layer; the conductive layer of molybdenum is less likely to react with the electrical contact layer. Therefore, a thinner bottom barrier layer can be used, to increase the thickness of the conductive layer and reduce the resistance of the conductive layer. Compared with tungsten, molybdenum is more difficult to etch, so the conductive layer can be provided with a more vertical side profile, which reduces the resistance of the conductive layer and improves the conductivity of the semiconductor structure. 
     In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the embodiments of the present disclosure are described below with reference to the drawings. Persons skilled in the art may understand that many technical details are proposed in the embodiments of the present disclosure to help readers better understand the present application. However, even without these technical details and various changes and modifications made based on the following embodiments, the technical solutions claimed in the present disclosure may still be realized. 
       FIG. 1  to  FIG. 6  are schematic structural diagrams corresponding to various steps of a method of manufacturing a semiconductor structure according to a first embodiment of the present disclosure. Details are described below with reference to the accompanying drawings. 
     Referring to  FIG. 1 , a base  100  is provided. 
     The base  100  can include an isolation structure  102  and an active region  101 . The isolation structure  102  is configured to isolate adjacent active regions  101 . A material of the isolation structure  102  is an insulating material, for example, silicon oxide, silicon nitride, silicon nitride or silicon carbide. A material of the active region  101  is a semiconductor material, such as silicon or germanium, and the semiconductor material further includes N-type doped ions or P-type doped ions. 
     In this embodiment, the base  100  is provided with an inner recess, so that an embedded electrical contact layer can be formed on the active region  101  exposed in the inner recess, thereby reducing the volume of the semiconductor structure and increasing the robustness of the semiconductor structure. In other embodiments, the base may also have a flat shape. 
     With reference to  FIG. 1  to  FIG. 4 , an electrical contact layer  103 , a bottom barrier layer  104 , and a conductive layer  105  that are sequentially stacked are formed on the base  100 . 
     The electrical contact layer  103  is located on the active region  101 , and is electrically connected to the active region  101 . The electrical contact layer  103  is further located in the inner recess of the isolation structure  102 , that is, the electrical contact layer  103  is partially embedded in the isolation structure  102 . 
     In this embodiment, a material of the electrical contact layer  103  is polycrystalline silicon. In other embodiments, the material of the electrical contact layer may also be metal or metal silicide. 
     The bottom barrier layer  104  is configured to electrically connect to the electrical contact layer  103  and the conductive layer  105 , and to block the ion diffusion between the electrical contact layer  103  and the conductive layer  105 . The bottom barrier layer  104  can further increase the adhesion of the conductive layer  105  to the electrical contact layer  103 , thereby improving the robustness of the semiconductor structure. 
     To reduce the interface defects between the bottom barrier layer  104  and the conductive layer  105 , and to further improve the adhesion of the bottom barrier layer  104  to the conductive layer  105 , the bottom barrier layer  104  can have the same type of ions as the conductive layer  105 . For example, a material of the bottom barrier layer  104  can be molybdenum nitride. In other embodiments, the material of the bottom barrier layer may also be titanium nitride, tantalum nitride, or tungsten nitride. 
     The conductive layer  105  includes a contact region  115  in contact with the bottom barrier layer  104  and a connection region  125  located on the contact region  115 . Compared with the connection region  125 , the contact region  115  is closer to the bottom barrier layer  104 . Therefore, ions in the contact region  115  and ions in the bottom barrier layer  104  are more likely to diffuse and react with each other. In order to reduce the degree of ion diffusion and reaction between the conductive layer  105  and the electrical contact layer  103 , molybdenum can be used as the material of the contact region  115 . 
     In this embodiment, the conductive layer  105  is a single-layer structure. That is, the contact region  115  and the connection region  125  of the conductive layer  105  are of an integrated structure, and materials of both the contact region  115  and the connection region  125  are molybdenum. Due to the low resistance of molybdenum, the use of molybdenum as the material of the whole conductive layer  105  can further reduce the resistance of the conductive layer  105 . Due to the low affinity between molybdenum and the electrical contact layer  103 , the use of molybdenum as the material of the whole conductive layer  105  can further reduce the degree of reaction between the conductive layer  105  and the electrical contact layer  103 ; since molybdenum is not easy to etch, the use of molybdenum as the material of the whole conductive layer  105  can further improve the verticality of the side surface of the conductive layer  105 . In this way, the resistance of the entire semiconductor structure can be reduced and the conductivity of the semiconductor structure can be improved. 
     In other embodiments, the material of the entire conductive layer can also be a molybdenum alloy. Alternatively, molybdenum can be used as the material of the connection region, and a conductive material such as tungsten, tantalum or titanium can be used as the material of the contact region. Alternatively, a conductive material such as tungsten, tantalum or titanium can be used as the material of the connection region and molybdenum can be used as the material of the contact region. 
     Steps for forming the electrical contact layer  103 , the conductive layer  105 , and the bottom barrier layer  104  are described in detail below. 
     Referring to  FIG. 1 , an initial electrical contact layer  103   a  is formed on the base  100 . The initial electrical contact layer  103   a  is formed in the inner recess of the isolation structure  102 ; the initial electrical contact layer  103   a  further covers a top surface of the isolation structure  102 . 
     In this embodiment, the initial electrical contact layer  103   a  is formed using a chemical vapor deposition process, which has a faster deposition speed. In other embodiments, the initial electrical contact layer can also be formed using a physical vapor deposition process. 
     An initial bottom barrier layer  104   a  is formed on the initial electrical contact layer  103   a . In this embodiment, the initial bottom barrier layer  104   a  is formed using a reactive magnetron sputtering method in the physical vapor deposition process. The reactive magnetron sputtering method has the advantages of simple equipment, easy control, and strong adhesion. In other embodiments, the initial bottom barrier layer can also be formed using a vacuum vapor deposition or ion plating method in the physical vapor deposition process. 
     An initial conductive layer  105   a  is formed on the initial bottom barrier layer. In this embodiment, the initial conductive layer  105   a  is formed using a reactive magnetron sputtering method in the physical vapor deposition process, and in other embodiments, the initial conductive layer can also be formed by the vacuum vapor deposition or ion plating in the physical vapor deposition process. 
     Referring to  FIG. 2 , in this embodiment, after the initial conductive layer  105   a  is formed, the method further includes a step of forming an initial top barrier layer  106   a  on the initial conductive layer  105   a . The initial top barrier layer  106   a  may prevent the initial conductive layer  105   a  from reacting with a subsequently formed insulation cover layer, to reduce the consumption of the initial conductive layer  105   a  by the insulation cover layer, thereby reducing the resistance of the semiconductor structure. 
     In this embodiment, compared with the degree of reaction between the initial conductive layer  105   a  and the initial electrical contact layer  103   a , the degree of reaction between the initial conductive layer  105   a  and the subsequently formed insulation cover layer is lower. In order to reduce the volume of the initial top barrier layer  106   a , the initial top barrier layer  106   a  may be thinner than the bottom barrier layer  104   a , which can increase the volume of the initial conductive layer  105   a , thereby reducing the resistance and improving the reaction speed of the semiconductor structure. 
     The initial conductive layer  105   a  is processed by using a remote plasma nitridation process, to form the initial top barrier layer  106   a . The remote plasma nitridation process means that there is a long distance between an ionization zone and a processing zone, i.e., plasma is synthesized in the ionization zone by using a plasma source, and then the plasma is introduced into the processing zone by an airflow, an electric field, or a magnetic field. In the processing zone, the plasma penetrates or is adsorbed on a top surface of the initial conductive layer  105   a  to form the initial top barrier layer  106   a . The material of the initial top barrier layer  106   a  is molybdenum nitride. The remote plasma nitridation process has a better plasma processing effect and can form a top barrier layer with a more uniform film thickness and a more appropriate ion ratio. 
     In other embodiments, the initial top barrier layer may be formed by physical vapor deposition; alternatively, the initial top barrier layer may not be formed on the initial conductive layer. 
     Referring to  FIG. 3 , an initial insulation cover layer  107   a  is formed on the initial top barrier layer  106   a.    
     The initial insulation cover layer  107   a  can protect the initial conductive layer  105   a  from damage during the subsequent fabrication process. A material of the initial insulation cover layer  107   a  includes silicon nitride, silicon carbide, silicon carbide or silicon dioxide. 
     In this embodiment, the initial insulation cover layer  107   a  is formed by chemical vapor deposition. In other embodiments, the initial insulation cover layer may be formed by physical vapor deposition. 
     Referring to  FIG. 4 , the initial electrical contact layer  103   a  (referring to  FIG. 3 ), the initial bottom barrier layer  104   a  (referring to  FIG. 3 ), and the initial conductive layer  105   a  (referring to  FIG. 3 ) are patterned, to form an electrical contact layer  103 , a bottom barrier layer  104 , and a conductive layer  105 . 
     In this embodiment, the initial top barrier layer  106   a  (referring to  FIG. 3 ) and the initial insulation cover layer  107   a  (referring to  FIG. 3 ) are further patterned, to form a top barrier layer  106  and an insulation cover layer  107 . 
     A patterned mask layer is formed on the initial insulation cover layer  107   a . Dry etching is performed on the initial electrical contact layer  103   a , the initial bottom barrier layer  104   a , the initial conductive layer  105   a , the initial top barrier layer  106   a , and the initial insulation cover layer  107   a  by using the patterned mask layer as a mask, to form the electrical contact layer  103 , the bottom barrier layer  104 , the conductive layer  105 , the top barrier layer  106 , and the insulation cover layer  107  that are sequentially stacked. 
     In the process of etching the initial insulation cover layer  107   a , an etching gas is carbon tetrafluoride. 
     In the process of etching the initial conductive layer  105   a , an etching gas is chlorine, with a flow rate of 10 sccm to 40 sccm; the flow rate within the above range ensures that the etching is completed in a short time, and also ensures a relatively vertical shape of the sidewall of the conductive layer  105 . 
     In the process of etching the initial top barrier layer  106   a  and the initial bottom barrier layer  104   a , an etching gas is at least one of chlorine, argon, nitrogen, etc. 
     In the process of etching the initial electrical contact layer  103   a , an etching gas is chlorine. 
     Referring to  FIG. 5 , in this embodiment, the method may further include a step of forming a sidewall barrier layer  108  on sidewalls of the conductive layer  105  by using a remote plasma nitridation process. The sidewall barrier layer  108  can block the ion diffusion between the conductive layer  105  and a subsequently formed protective layer, thus ensuring low resistance of the conductive layer  105 ; the sidewall barrier layer  108  can also improve the adhesion between the conductive layer  105  and the subsequently formed protective layer, and improve the robustness of the semiconductor structure. 
     In this embodiment, the electrical contact layer  103 , the conductive layer  105 , the top barrier layer  106 , the bottom barrier layer  104 , and the sidewall barrier layer  108  may form a bit line structure. 
     Referring to  FIG. 6 , a protective layer  109  is formed. The protective layer  109  covers a top surface and sidewalls of the insulation cover layer  107 . The protective layer  109  is further located on sidewalls of the top barrier layer  106 , sidewalls of the sidewall barrier layer  108 , sidewalls of the bottom barrier layer  104 , and sidewalls of the electrical contact layer  103 . The protective layer  109  further fills the inner recess of the base  100 . 
     The protective layer  109  can isolate the bit line structure from the subsequently formed semiconductor structure. A material of the protective layer  109  may be silicon nitride, silicon nitride oxide or silicon carbon nitride. 
     A dielectric layer  110  is formed on sidewalls of the protective layer  109 . The dielectric layer  110  can reduce the parasitic capacitance between bit line structures, thereby improving the performance of the semiconductor structure. A material of the dielectric layer  110  may be a material with a low dielectric constant. 
     An insulation layer  111  is formed on sidewalls of the dielectric layer  110  and a top surface of the protective layer  109 . The insulation layer  111  may isolate the bit line structure from a subsequently capacitance contact layer, so as to avoid an electrical connection between the bit line structure and the capacitance contact layer. 
     In summary, the conductive layer  105  of the first embodiment of the present disclosure is a single-layer structure, and the material of the entire conductive layer  105  is molybdenum, which can further reduce the resistance of the conductive layer  105 , further reduce the degree of reaction between the conductive layer  105  and the electrical contact layer  103 , and improve the verticality of the sidewalls of the conductive layer  105 , thereby improving the performance of the semiconductor structure. 
     A second embodiment of the present disclosure provides a method of manufacturing a semiconductor structure. This embodiment is generally the same as the first embodiment, except that in this embodiment, the conductive layer is a multi-layer structure; the conductive layer includes a contact region in contact with the bottom barrier layer and a connection region located on the contact region; a material of the contact region includes molybdenum, and an etching rate of the connection region is higher than an etching rate of the contact region under the same etching condition. 
       FIG. 7  to  FIG. 10  show the method of manufacturing a semiconductor structure according to the second embodiment of the present disclosure. For the parts of this embodiment that are the same as or similar to the first embodiment, refer to the first embodiment. Details are not described herein again. 
     Referring to  FIG. 7  to  FIG. 8 , an electrical contact layer  203 , a bottom barrier layer  204 , and a conductive layer  215  that are sequentially stacked are formed on a base  200 . 
     Referring to  FIG. 7 , the base  200  includes an active region  201  and an isolation structure  202  that isolates adjacent active regions  201 . 
     An initial electrical contact layer  203   a , an initial bottom barrier layer  204   a , an initial conductive layer  215   a , an initial top barrier layer  206   a , and an initial insulation cover layer  207   a  that are sequentially stacked are formed on the base  200 . The initial conductive layer  215   a  includes an initial contact region  205   a  and an initial connection region  209   a  that are sequentially stacked. 
     Referring to  FIG. 8 , patterning is performed to form an electrical contact layer  203 , a bottom barrier layer  204 , a conductive layer  215 , a top barrier layer  206 , and an insulation cover layer  207  that are sequentially stacked. 
     For details of the structure of the base  200  and the steps for forming the electrical contact layer  203 , the bottom barrier layer  204 , the conductive layer  215 , the top barrier layer  206 , and the insulation cover layer  207 , refer to the first embodiment. 
     In this embodiment, the conductive layer  215  is a multi-layer structure. The conductive layer  215  includes a contact region  205  in contact with the bottom barrier layer  204  and a connection region  209  located on the contact region  205 . A material of the contact region  205  is molybdenum. Due to the low affinity of molybdenum with the electrical contact layer  203 , the material, which is in direct contact with the contact region  205 , is molybdenum in the electrical contact layer  203 . This can reduce the degree of reaction between the conductive layer  215  and the electrical contact layer  203 . Since molybdenum is difficult to etch, the use of molybdenum as the material of the contact region  205  can improve the verticality of the sidewalls of the contact region  205 . In other embodiments, the material of the contact region may be a molybdenum alloy. 
     Under the same etching condition, an etching rate of the connection region  209  is higher than an etching rate of the contact region  205 . It can be understood that, since the contact region  205  is difficult to etch, a higher etching rate of the connection region  209  can reduce the etching time of the conductive layer  215  to some extent, thereby improving the process efficiency and reducing the production cost. 
     In this embodiment, a material of the connection region  209  is tungsten; in other embodiments, the material of the connection region may also be tantalum. 
     In a direction perpendicular to the base  200 , a thickness ratio between the contact region  205  and the connection region  209  can be controlled within a range from 2:1 to 3:1. It can be understood that a middle region of the initial conductive layer  215   a  has a larger contact area with the etching gas. Therefore, the sidewalls in the middle region have a higher risk of over-etching than in the top and bottom regions. If the material in the middle region is molybdenum, which is more difficult to etch, the sidewalls are less likely to be over-etched. When the thickness ratio between the contact region  205  and the connection region  209  is in the range of 2:1 to 3:1, i.e., the thickness ratio between the initial contact region  205   a  and the initial connection region  209   a  is in the range of 2:1 to 3:1, the initial contact region  205   a  can occupy more of the middle region of the initial conductive layer  215   a , while the initial connection region  209   a  mainly occupies the top region of the initial conductive layer  215   a . In this way, the verticality of the sidewalls of the conductive layer  215  can be further improved. The thickness ratio within the above range can also control the etching time to be in a smaller range. 
     In this embodiment, in the process of etching the initial contact region  205   a , an etching gas is chlorine, with an etching flow rate of 10 sccm to 40 sccm. Within the etching flow rate range described above, the process time can be reduced to some extent, and the formed contact region  205  can be guaranteed to have a vertical sidewall shape. 
     In the process of etching the initial connection region  209   a , an etching gas is chlorine, with an etching flow rate of 5 sccm to 20 sccm. Within the etching flow rate range described above, the process time can be reduced to some extent, and the formed connection region  209  can be guaranteed to have a vertical sidewall shape. 
     Referring to  FIG. 9 , a sidewall barrier layer  211  is formed by using a remote plasma process. The sidewall barrier layer  211  is configured to block the ion diffusion between the conductive layer  215  and a subsequently formed protective layer and improve the adhesion between the conductive layer  215  and the protective layer, thereby improving the performance of the semiconductor structure. 
     The sidewall barrier layer  211  includes a first barrier layer  208  located on sidewalls of the contact region  205  and a second barrier layer  210  located on sidewalls of the connection region  209 . In this embodiment, a material of the first barrier layer  208  is molybdenum nitride, and a material of the second barrier layer  210  is tungsten nitride. 
     Referring to  FIG. 10 , a protective layer  212  is formed. The protective layer  212  covers a top surface and sidewalls of the insulation cover layer  207 . The protective layer  212  is further located on sidewalls of the top barrier layer  206 , sidewalls of the sidewall barrier layer  211 , sidewalls of the bottom barrier layer  204 , and sidewalls of the electrical contact layer  203 . The protective layer  212  further fills the inner recess of the base  200 . 
     A dielectric layer  213  is formed on sidewalls of the protective layer  212 . 
     An insulation layer  214  is formed on sidewalls of the dielectric layer  213  and a top surface of the protective layer  212 . 
     For detailed descriptions of the foregoing steps, refer to the first embodiment. 
     In conclusion, in this embodiment, the conductive layer  215  is a multi-layer structure, including a contact region  205  and a connection region  209  that are stacked. The etching rate of the connection region  209  is higher than the etching rate of the contact region  205 . The material of the contact region is molybdenum, and the material of the connection region  209  is tungsten. With the advantages of the two materials, the degree of reaction between the contact region  205  and the electrical contact layer  203  is reduced, and the resistance of the conductive layer  215  is reduced. Moreover, the etching time is reduced. 
     A third embodiment of the present disclosure provides a semiconductor structure.  FIG. 10  is a schematic diagram of a semiconductor structure according to an embodiment of the present disclosure. Referring to  FIG. 10 , the semiconductor structure includes: a base  200 ; an electrical contact layer  203  located on the base  200 ; a bottom barrier layer  204  located on the electrical contact layer  203 ; and a conductive layer  215  located on the bottom barrier layer  204 , a material of the conductive layer  215  including molybdenum. 
     Details are described below with reference to the accompanying drawings. 
     The base  200  may include an isolation structure  202  and an active region  201 . The isolation structure  202  is configured to isolate adjacent active regions  201 . A material of the isolation structure  202  is an insulating material, for example, silicon oxide, silicon nitride, silicon nitride or silicon carbide. A material of the active region  201  is a semiconductor material, such as silicon or germanium, and the semiconductor material further includes N-type doped ions or P-type doped ions. 
     In this embodiment, the base  200  is provided with an inner recess, so that an embedded electrical contact layer  203  can be formed in the inner recess, thereby reducing the volume of the semiconductor structure and increasing the robustness of the semiconductor structure. In other embodiments, the base  200  may also have a flat shape. 
     The electrical contact layer  203  is electrically connected to the active region  201 . A material of the electrical contact layer  203  is polycrystalline silicon. In other embodiments, the material of the electrical contact layer may also be metal or metal silicide. 
     In this embodiment, the conductive layer  215  is a multi-layer structure. The conductive layer  215  further includes a contact region  205  in contact with the bottom barrier layer  204  and a connection region  209  located on the contact region  205 . A material of the contact region  205  is molybdenum. Due to the low affinity of molybdenum with the electrical contact layer  203 , the material, which is in direct contact with the contact region  205 , is molybdenum in the electrical contact layer  203 . This can reduce the degree of reaction between the conductive layer  215  and the electrical contact layer  203 . Since molybdenum is difficult to etch, the use of molybdenum as the material of the contact region  205  can improve the verticality of the sidewalls of the contact region  205 . In other embodiments, the material of the contact region may be a molybdenum alloy. 
     Under the same etching condition, an etching rate of the connection region  209  is higher than an etching rate of the contact region  205 . It can be understood that, since the contact region  205  is difficult to etch, a higher etching rate of the connection region  209  can reduce the etching time of the conductive layer  215  to some extent, thereby improving the process efficiency and reducing the production cost. 
     In this embodiment, a material of the connection region  209  is tungsten; in other embodiments, the material of the connection region may also be tantalum. 
     The conductive layer  215  has a thickness of 20 nm to 40 nm, such as 30 nm, in a direction perpendicular to a top surface of the base  200 . When the thickness of the conductive layer  215  is within the above range, it not only ensures small resistance of the semiconductor structure but also ensures a small volume of the conductive layer, thereby reducing the size of the semiconductor structure. 
     In other embodiments, referring to  FIG. 6 , the conductive layer  105  is a single-layer structure. That is, the contact region  115  and the connection region  125  of the conductive layer  105  are of an integrated structure, and materials of both the contact region  115  and the connection region  125  are molybdenum. Due to the low resistance of molybdenum, the use of molybdenum as the material of the whole conductive layer  105  can further reduce the resistance of the conductive layer  105 . Due to the low affinity between molybdenum and the electrical contact layer  103 , the use of molybdenum as the material of the whole conductive layer  105  can further reduce the degree of reaction between the conductive layer  105  and the electrical contact layer  103 ; since molybdenum is not easy to etch, the use of molybdenum as the material of the whole conductive layer  105  can further improve the verticality of the side surface of the conductive layer  105 . In this way, the resistance of the entire semiconductor structure is reduced and the conductivity of the semiconductor structure is improved. 
     Referring to  FIG. 10 , the bottom barrier layer  204  is configured to prevent reaction between the electrical contact layer  203  and the conductive layer  215 . It can be understood that if the bottom barrier layer  204  has the same type of ions as the conductive layer  215 , there will be fewer defects at the interface between the two and the adhesion can be further improved, thus increasing the robustness of the semiconductor structure. In this embodiment, a material of the bottom barrier layer  204  is molybdenum nitride. In other embodiments, the material of the bottom barrier layer may also be titanium nitride or tantalum nitride. 
     The semiconductor structure further includes: a top barrier layer  206  located on the conductive layer  215 . The top barrier layer  206  can prevent the conductive layer  215  from reacting with an insulation cover layer  207 , to reduce the consumption of the conductive layer  215  by the insulation cover layer  207 , thereby reducing the resistance of the semiconductor structure. 
     A thickness of the bottom barrier layer  204  is greater than a thickness of the top barrier layer  206 . In this embodiment, compared with the degree of reaction between the conductive layer  215  and the electrical contact layer  203 , the degree of reaction between the conductive layer  215  and the insulation cover layer  207  is lower. Therefore, in order to reduce the volume of the top barrier layer  206 , the top barrier layer  206  may be thinner than the bottom barrier layer  204 , which can increase the volume of the conductive layer  215 , thereby reducing the resistance and improving the conductivity of the semiconductor structure. 
     In this embodiment, the bottom barrier layer  204  has a thickness of 1 nm to 5 nm, such as 3 nm, in a direction perpendicular to a top surface of the base  200 . When the thickness of the bottom barrier layer  204  is in the range described above, it ensures a good blocking effect of the bottom barrier layer  204  and also ensures a small volume of the bottom barrier layer  204 , thereby reducing the resistance of the semiconductor structure. 
     The top barrier layer  206  has a thickness of 0.1 nm to 1 nm in the direction perpendicular to the top surface of the base. When the thickness of the top barrier layer  206  is in the range described above, it ensures a good blocking effect of the top barrier layer  206  and also ensures a small volume of the top barrier layer  206 , thereby reducing the resistance of the semiconductor structure. 
     The semiconductor structure further includes: a sidewall barrier layer  211  located on sidewalls of the conductive layer  215 . In this embodiment, the sidewall barrier layer  211  includes a first barrier layer  208  located on sidewalls of the contact region  205  and a second barrier layer  210  located on sidewalls of the connection region  209 . In this embodiment, a material of the first barrier layer  208  is molybdenum nitride, and a material of the second barrier layer  210  is nitride. 
     The sidewall barrier layer  211  has a thickness of 0.1 nm to 1 nm in a direction parallel to the top surface of the base  200 . When the thickness of the sidewall barrier layer  211  is in the range described above, it ensures a good blocking effect of the sidewall barrier layer  211  and also ensures a small volume of the sidewall barrier layer  211 , thereby reducing the resistance of the semiconductor structure. 
     The semiconductor structure further includes: a protective layer  212 . The protective layer  212  covers a top surface and sidewalls of the insulation cover layer  207 . The protective layer  212  is further located on sidewalls of the top barrier layer  206 , sidewalls of the sidewall barrier layer  211 , sidewalls of the bottom barrier layer  204 , and sidewalls of the electrical contact layer  203 . The protective layer  212  further fills the inner recess. 
     The semiconductor structure further includes: a dielectric layer  213  located on sidewalls of the protective layer  212 . 
     The semiconductor structure further includes: an insulation layer  214  located on sidewalls of the dielectric layer  213  and a top surface of the protective layer  212 . 
     For details about the protective layer  212 , the dielectric layer  213 , and the insulation layer  214 , refer to the first embodiment. 
     In conclusion, the conductive layer  215  is a multi-layer structure, including a contact region  205  and a connection region  209  that are stacked. The etching rate of the connection region  209  is higher than that of the contact region  205 . The material of the contact region  205  is molybdenum, and the material of the connection region  209  is tungsten. With the advantages of the two materials, the degree of reaction between the contact region  205  and the electrical contact layer  203  is reduced, and the resistance of the conductive layer  215  is reduced. Moreover, the etching time can be reduced. 
     Each embodiment or implementation in the specification of the present disclosure is described in a progressive manner. Each embodiment focuses on the difference from other embodiments, and the same and similar parts between the embodiments may refer to each other. 
     In the description of the specification, the description with reference to terms such as “an embodiment”, “an illustrative embodiment”, “some implementations”, “an illustrative implementation” and “an example” means that the specific feature, structure, material or feature described in combination with the implementation(s) or example(s) is included in at least one implementation or example of the present disclosure. 
     In this specification, the schematic expression of the above terms does not necessarily refer to the same implementation or example. Moreover, the described specific feature, structure, material or characteristic may be combined in an appropriate manner in any one or more implementations or examples. 
     It should be noted that in the description of the present disclosure, the terms such as “center”, “top”, “bottom”, “left”, “right”, “vertical”, “horizontal”, “inner” and “outer” indicate the orientation or position relationships based on the drawings. These terms are merely intended to facilitate description of the present disclosure and simplify the description, rather than to indicate or imply that the mentioned device or element must have a specific orientation and must be constructed and operated in a specific orientation. Therefore, these terms should not be construed as a limitation to the present disclosure. 
     It can be understood that the terms such as “first” and “second” used in the present disclosure can be used to describe various structures, but these structures are not limited by these terms. Instead, these terms are merely intended to distinguish one element from another. 
     The same elements in one or more drawings are denoted by similar reference numerals. For the sake of clarity, various parts in the drawings are not drawn to scale. In addition, some well-known parts may not be shown. For the sake of brevity, the structure obtained by implementing multiple steps may be shown in one figure. In order to make the understanding of the present disclosure more clearly, many specific details of the present disclosure, such as the structure, material, size, processing process and technology of the device, are described below. However, as those skilled in the art can understand, the present disclosure may not be implemented according to these specific details. 
     Finally, it should be noted that the above embodiments are merely intended to explain the technical solutions of the present disclosure, rather than to limit the present disclosure. Although the present disclosure is described in detail with reference to the above embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the above embodiments, or make equivalent substitutions of some or all of the technical features recorded therein, without deviating the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     The method of manufacturing a semiconductor structure and the semiconductor structure provided in the embodiments of the present disclosure can reduce the resistance of the semiconductor structure and improve the conductive performance of the semiconductor structure.