Semiconductor structure and method for forming the same

Abstract

An embodiment of the present invention provides a semiconductor structure and a method for forming the same, wherein the method for forming the semiconductor structure comprises: providing a substrate, on which a dielectric layer is disposed, the dielectric layer having a groove; forming a metal copper layer filling the groove; forming a contact layer on the upper surface of the metal copper layer, the material of the contact layer containing cuprous ions; forming a barrier layer on the upper surface of the contact layer, the material of the barrier layer and the material of the contact layer containing the same element. The embodiment of the present invention is conducive to improving the contact effect between the metal copper layer and the barrier layer.

Description

Technical Field

[0001] The embodiments of the present invention relate to the semiconductor field, and in particular to a semiconductor structure and a method for forming the same. Background Art

[0002] Dynamic random access memory is a semiconductor memory widely used in multi-computer systems. With the rapid development of semiconductor integrated circuit devices, the requirements for the contact effect between various structures in semiconductor integrated circuit devices are becoming higher and higher.

[0003] The metal copper layer plays an important role in the interconnection of integrated circuits. In the prior art, a barrier layer is formed on the surface of the metal copper layer to prevent the metal copper layer from diffusing to other areas. However, the contact effect between the metal copper layer and the barrier layer is poor. The metal copper layer is easy to diffuse along the contact surface with the barrier layer, forming gaps or protrusions in the semiconductor structure.

[0004] How to improve the contact effect between the metal copper layer and the barrier layer has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] The embodiments of the present invention provide a semiconductor structure and a method for forming the same, which are beneficial to solving the problem of poor contact between a metal copper layer and a barrier layer.

[0006] To solve the above problems, an embodiment of the present invention provides a method for forming a semiconductor structure, comprising: providing a substrate, on which a dielectric layer is arranged, and the dielectric layer has a groove; forming a metal copper layer filling the groove; forming a contact layer on the upper surface of the metal copper layer, and the material of the contact layer contains cuprous ions; forming a barrier layer on the upper surface of the contact layer, and the material of the barrier layer and the material of the contact layer contain the same element.

[0007] In addition, the material of the contact layer includes cuprous thiocyanate, and the material of the barrier layer includes silicon carbonitride.

[0008] In addition, the steps of forming the contact layer are: forming an initial contact layer by a spin coating process; and performing a heat treatment on the initial contact layer to form the contact layer.

[0009] In addition, the spin coating process includes: during the spin coating, the substrate, the dielectric layer and the metal copper layer rotate at a rate of 500 to 3000 revolutions per minute.

[0010] In addition, the heat treatment process includes: when the initial contact layer is heat treated, the process temperature is 70 degrees Celsius to 80 degrees Celsius; the process time is 10 minutes to 20 minutes.

[0011] In addition, before forming the contact layer, the method further includes: forming a buffer layer on the upper surface of the dielectric layer and the upper surface of the metal copper layer; and etching away a portion of the buffer layer located on the upper surface of the metal copper layer to expose at least the entire upper surface of the metal copper layer.

[0012] In addition, after etching away a portion of the buffer layer located on the upper surface of the metal copper layer, the contact layer is formed on the entire exposed upper surface of the metal copper layer, and the upper surface of the contact layer is flush with the upper surface of the remaining portion of the buffer layer.

[0013] In addition, forming the barrier layer includes: forming the barrier layer on the upper surface of the contact layer and the upper surface of the remaining portion of the buffer layer.

[0014] In addition, after forming the barrier layer, the method further includes: forming a metal layer penetrating the barrier layer and the contact layer, wherein the metal layer contacts the upper surface of the metal copper layer.

[0015] In addition, forming the metal layer includes: etching and removing a portion of the barrier layer and a portion of the contact layer to expose a portion of the upper surface of the metal copper layer; and forming the metal layer on the exposed portion of the upper surface of the metal copper layer.

[0016] An embodiment of the present invention also provides a semiconductor structure, comprising: a substrate, wherein a dielectric layer is provided on the substrate, wherein a metal copper layer is provided in the dielectric layer, and wherein the dielectric layer exposes the upper surface of the metal copper layer; a contact layer, wherein the contact layer is located on the upper surface of the metal copper layer, and wherein the material of the contact layer contains cuprous ions; and a barrier layer, wherein the barrier layer is located on the upper surface of the contact layer, and wherein the material of the barrier layer contains the same element as the material of the contact layer.

[0017] In addition, the invention further comprises a buffer layer, wherein the buffer layer is located between the dielectric layer and the barrier layer, and the upper surface of the buffer layer is flush with the upper surface of the contact layer.

[0018] In addition, the thickness of the contact layer is 5 nanometers to 10 nanometers.

[0019] In addition, the thickness of the buffer layer is 5 nanometers to 10 nanometers.

[0020] In addition, it also includes: a metal layer, the metal layer penetrates the barrier layer and the contact layer, and the metal layer contacts the upper surface of the metal copper layer.

[0021] Compared with the prior art, the technical solution provided by the embodiment of the present invention has the following advantages:

[0022] The method for forming a semiconductor structure provided by an embodiment of the present invention forms a contact layer between a metal copper layer and a barrier layer, wherein the material of the contact layer contains cuprous ions, and the material of the contact layer and the material of the barrier layer contain the same element. Because the contact layer contains cuprous ions and has similar chemical properties to the metal copper layer, the contact layer formed on the upper surface of the metal copper layer has good adhesion to the metal copper layer, and there is no gap between the metal copper layer and the contact layer; at the same time, because the material of the contact layer and the material of the barrier layer contain the same element, the contact layer and the barrier layer also have similar chemical properties, and there is good adhesion between the two. In summary, the contact layer is tightly bonded to the metal copper layer and the barrier layer on opposite sides, respectively, and there is no gap or protrusion between the metal copper layer and the barrier layer, thereby improving the contact performance between the metal copper layer and the barrier layer.

[0023] In the method for forming a semiconductor structure provided by an embodiment of the present invention, a buffer layer is formed between the dielectric layer and the barrier layer, and the upper surface of the buffer layer is flush with the upper surface of the contact layer. Because the contact layer contains cuprous ions, in order to prevent the two sides of the contact layer from contacting and conducting with other structures in the semiconductor structure, buffer layers are formed on both sides of the contact layer, which has the effect of isolation and insulation, and is beneficial to improving the safety of the semiconductor structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0025] Figure 1 is a schematic structural diagram of a semiconductor structure;

[0026] Figure 2 to Figure 11 A schematic structural diagram corresponding to each step of a method for forming a semiconductor structure provided by the first embodiment of the present invention;

[0027] Fig.12 A schematic structural diagram of a semiconductor structure provided for a second embodiment of the present invention. DETAILED DESCRIPTION

[0028] As can be seen from the background art, the contact effect between the metal copper layer and the barrier layer in the prior art is poor.

[0029] refer to Figure 1 A semiconductor structure includes: a substrate 200, a dielectric layer 201, a metal copper layer 203, a barrier layer 207, and a metal layer 209.

[0030] Among them, the barrier layer 207 is located on the upper surface of the dielectric layer 201 and the upper surface of the metal copper layer 203. Since the contact effect between the metal copper layer 203 and the barrier layer 207 is poor, there is a gap between the metal copper layer 203 and the barrier layer 207. After the metal layer 209 electrically connected to the metal copper layer 203 is formed, the flow of electrons causes the physical form of the metal copper layer 203 to become active, the metal copper layer 203 flows between the gaps, part of the metal copper layer 203 is raised, and a gap 210 is formed between the metal copper layer 203 and the barrier layer 207, thereby reducing the performance of the semiconductor structure.

[0031] To solve the above problems, the present invention provides a method for forming a semiconductor structure, wherein a contact layer is formed between the metal copper layer and the barrier layer, the material of the contact layer contains cuprous ions, and the material of the contact layer and the material of the barrier layer contain the same elements, thereby improving the contact effect between the metal copper layer and the barrier layer in the semiconductor structure.

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are provided to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0033] Figure 2 to Figure 11 The schematic diagram of each step of a method for forming a semiconductor structure provided by the first embodiment of the present invention is shown in FIG.

[0034] refer to Figure 2 The first embodiment of the present invention provides a method for forming a semiconductor structure, comprising: providing a substrate 100 , on which a dielectric layer 101 is disposed, and the dielectric layer 101 has a groove 102 .

[0035] The material of the substrate 100 may include sapphire, silicon, silicon carbide, gallium arsenide, aluminum nitride or zinc oxide, etc. In this embodiment, the substrate 100 is made of silicon.

[0036] A dielectric layer 101 is formed on the surface of the substrate 100. The dielectric layer 101 may be formed by chemical vapor deposition or by atomic layer deposition.

[0037] The material of the dielectric layer 101 may be silicon oxide or a high dielectric material. The high dielectric material may specifically be a ferroelectric ceramic material, a barium titanate material or a lead titanate material.

[0038] In this embodiment, the trench 102 is formed in the dielectric layer 101. The dual damascene process may be used to form the trench 102. The dual damascene process includes a via first trench last method and a via last trench first method.

[0039] refer to Figure 3 , forming a filled trench 102 (refer to Figure 2 ) of the metal copper layer 103. The metal copper layer 103 may be formed by chemical vapor deposition. In other embodiments, the metal copper layer may also be formed by atomic layer deposition.

[0040] refer to Figure 4 A buffer layer 104 is formed on the upper surface of the dielectric layer 101 and the upper surface of the metal copper layer 103 .

[0041] A buffer layer 104 is formed between the dielectric layer 101 and the barrier layer. Because the contact layer contains cuprous ions, in order to prevent the two sides of the contact layer from contacting and conducting with other structures in the semiconductor structure, the buffer layer 104 is formed on both sides of the contact layer to achieve isolation and insulation, which is beneficial to improving the safety of the semiconductor structure.

[0042] The buffer layer 104 may be formed by an atomic layer deposition process, and the atomic layer deposition process may form a buffer layer 104 with a uniform thickness on the dielectric layer 101 and the metal copper layer 103. In other embodiments, the buffer layer may also be formed by a chemical vapor deposition process.

[0043] The buffer layer 104 plays a role of isolation and insulation. The material of the buffer layer 104 may be silicon nitride or silicon oxide.

[0044] In this embodiment, the thickness of the buffer layer 104 is 5 nm to 10 nm, specifically 6 nm, 7 nm or 8 nm. The buffer layer 104 only needs to play the role of isolation and insulation, so the thickness of the formed buffer layer 104 is relatively small, which is conducive to saving the production cost of the semiconductor structure.

[0045] refer to Figure 5 and Figure 6 , a portion of the buffer layer 104 located on the upper surface of the metal copper layer 103 is etched away to expose at least the entire upper surface of the metal copper layer 103 .

[0046] In this embodiment, the step of etching and removing a portion of the buffer layer 104 located on the upper surface of the metal copper layer 103 includes:

[0047] A photoresist 105 is formed on a portion of the buffer layer 104 on the upper surface of the dielectric layer 101 . According to its chemical reaction mechanism and development principle, it can be divided into two types: negative photoresist and positive photoresist. In this embodiment, a positive photoresist is used to remove a portion of the buffer layer 104 on the upper surface of the metal copper layer 103 .

[0048] Exposure and development steps are performed to remove a portion of the buffer layer 104 located on the upper surface of the metal copper layer 103 ; and the photoresist 105 is etched using oxygen-containing plasma to remove the photoresist 105 .

[0049] refer to Figure 7 and Figure 8 After etching away a portion of the buffer layer 104 on the upper surface of the metal copper layer 103 , a contact layer 106 is formed on the entire exposed upper surface of the metal copper layer 103 , and the upper surface of the contact layer 106 is flush with the upper surface of the remaining portion of the buffer layer 104 .

[0050] In this embodiment, the step of forming the contact layer 106 is: forming an initial contact layer by a spin coating process (Spin On Dielectric, SOD). In the SOD process, the substrate 100, the dielectric layer 101 and the metal copper layer 103 are first rotated at a certain rotation speed, and a fluid precursor is provided to the upper surface of the metal copper layer 103. The precursor is subjected to the centripetal force brought by the rotation on the upper surface of the metal copper layer 103. Under the centripetal force, the precursor diffuses to the surroundings to form a uniform initial contact layer of the fluid that fills the gap between the metal copper layer 103 and the buffer layer 104. Subsequently, the solid contact layer 106 is formed by sintering in an oxygen environment.

[0051] The initial contact layer is formed by using the SOD process. Due to the centripetal force brought by the rotation, the formed initial contact layer evenly fills the gap between the metal copper layer 103 and the buffer layer 104 .

[0052] In other embodiments, a fluid chemical vapor deposition (FCVD) process is also used to form the initial contact layer.

[0053] In this embodiment, the spin coating process includes: in the process of forming the initial contact layer by spin coating, the substrate 100, the dielectric layer 101 and the metal copper layer 103 rotate at a rate of 500 to 3000 revolutions per minute, specifically 1000 revolutions per minute, 1500 revolutions per minute or 2000 revolutions per minute.

[0054] After the initial contact layer is formed, the initial contact layer is heat-treated to form the contact layer 106. The heat treatment is to sinter the initial contact layer in an oxygen environment to form the contact layer 106 in a solid state.

[0055] In this embodiment, the heat treatment process includes: when the initial contact layer is heat treated, the process temperature is 70 degrees Celsius to 80 degrees Celsius, specifically 73 degrees Celsius, 76 degrees Celsius or 79 degrees Celsius; the process time is 10 minutes to 20 minutes, specifically 13 minutes, 16 minutes or 19 minutes.

[0056] The material of the contact layer 106 contains cuprous ions, specifically cuprous thiocyanate. Because the contact layer 106 contains cuprous ions and has similar chemical properties to the metal copper layer 103, the contact layer 106 formed on the upper surface of the metal copper layer 103 has good adhesion to the metal copper layer 103, and there is no gap between the metal copper layer 103 and the contact layer 106.

[0057] refer to Figure 7 Since the contact layer 106 is formed not only on the upper surface of the metal copper layer 103, but also on the upper surface of the buffer layer 104, and the upper surface of the contact layer 106 is higher than the upper surface of the remaining buffer layer 104, in order to make the upper surface of the contact layer 106 flush with the upper surface of the remaining buffer layer 104, the contact layer 106 needs to be chemically mechanically polished (CMP).

[0058] The chemical mechanical polishing process not only removes the contact layer 106 located on the upper surface of the buffer layer 104, so that the upper surface of the contact layer 106 after chemical mechanical polishing is flush with the upper surface of the buffer layer 104, but also the upper surface of the contact layer 106 after chemical mechanical polishing is flatter. Subsequently, a barrier layer is formed on the contact layer 106. Since the upper surface of the contact layer 106 has a high flatness, no gap will be generated between the contact layer 106 and the barrier layer due to the roughness of the upper surface of the contact layer 106.

[0059] During the chemical mechanical polishing process to remove a portion of the contact layer 106 , the specific polishing time may be 10 to 50 seconds, such as 20 seconds, 30 seconds or 40 seconds.

[0060] After the chemical mechanical polishing, the contact layer 106 is cleaned. The cleaning solution used in the cleaning process can be made of ammonia water and pure water in a ratio of 4:1 to 1:1, specifically 2:1.

[0061] The thickness of the contact layer 106 formed after chemical mechanical polishing is 5 nanometers to 10 nanometers, and specifically may be 6 nanometers, 7 nanometers or 8 nanometers.

[0062] The thickness of the contact layer 106 is the same as that of the buffer layer 104. The upper surface of the contact layer 106 forms a uniform and flat surface with the upper surface of the buffer layer 104, which is conducive to the subsequent deposition to form a barrier layer. Moreover, the contact layer 106 only needs to connect the metal copper layer 103 and the barrier layer, so the thickness of the formed contact layer 106 is relatively small, which is conducive to saving the production cost of the semiconductor structure.

[0063] refer to Fig. 9 , a barrier layer 107 is formed on the upper surface of the contact layer 106 .

[0064] In this embodiment, the step of forming the barrier layer 107 includes: forming the barrier layer 107 on the upper surface of the contact layer 106 and the upper surface of the remaining portion of the buffer layer 104. The barrier layer 107 may be formed by chemical vapor deposition. In other embodiments, the barrier layer may also be formed by atomic layer deposition.

[0065] In this embodiment, the material of the barrier layer 107 and the material of the contact layer 106 contain the same element. Specifically, the material of the barrier layer 107 may be silicon carbonitride. In other embodiments, the material of the barrier layer may be tantalum compounds such as tantalum nitride.

[0066] Because the material of the contact layer 106 and the material of the barrier layer 107 contain the same elements, the contact layer 106 and the barrier layer 107 also have similar chemical properties and good adhesion between the two. There is no gap between the barrier layer 107 and the contact layer 106. It can be obtained that the opposite sides of the contact layer 106 are tightly bonded to the metal copper layer 103 and the barrier layer 107 respectively, and there is no gap or protrusion between the metal copper layer 103 and the barrier layer 107, thereby improving the contact performance between the metal copper layer 103 and the barrier layer 107.

[0067] refer to Fig.10 and Fig.11 After forming the barrier layer 107, the method further includes: forming a metal layer 109 penetrating the barrier layer 107 and the contact layer 106, wherein the metal layer 109 contacts the upper surface of the metal copper layer 103. The metal layer 109 contacts the metal copper layer 103, and the two are electrically connected to form a conductive path.

[0068] In this embodiment, the step of forming the metal layer 109 includes: etching away part of the barrier layer 107 and part of the contact layer 106 to expose part of the upper surface of the metal copper layer 103 to form a through hole 108 ; and forming the metal layer 109 on the exposed upper surface of the metal copper layer 103 .

[0069] The process for forming the through hole 108 may be a dry etching process. The through hole 108 formed by the dry etching process has a more regular shape, which facilitates the subsequent formation of a metal layer with a regular shape in the through hole 108. In other embodiments, a wet etching process may also be used to form the through hole.

[0070] The metal layer 109 may be formed by chemical vapor deposition process. In other embodiments, the metal layer may also be formed by atomic layer deposition process.

[0071] The material of the metal layer 109 includes: tungsten metal, copper metal, aluminum metal, gold metal or silver metal. The gas used to form the metal layer 109 made of tungsten metal includes silane and tungsten hexafluoride. In other embodiments, tungsten metal can also be made of diboron hexahydride and tungsten hexafluoride.

[0072] The method for forming a semiconductor structure provided in this embodiment forms a contact layer between the metal copper layer and the barrier layer, the material of the contact layer contains cuprous ions, and the material of the contact layer and the material of the barrier layer contain the same element. Because the contact layer contains cuprous ions and has similar chemical properties to the metal copper layer, the contact layer formed on the upper surface of the metal copper layer has good adhesion to the metal copper layer, and there is no gap between the metal copper layer and the contact layer; at the same time, because the material of the contact layer and the material of the barrier layer contain the same element, the contact layer and the barrier layer also have similar chemical properties, and there is good adhesion between the two. In summary, the contact layer is tightly bonded to the metal copper layer and the barrier layer on opposite sides, and there is no gap or protrusion between the metal copper layer and the barrier layer, which improves the contact performance between the metal copper layer and the barrier layer.

[0073] The second embodiment of the present invention provides a semiconductor structure, which can be formed according to the semiconductor structure forming method of the first embodiment. The semiconductor structure provided by the second embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0074] Fig.12 A schematic structural diagram of a semiconductor structure provided for a second embodiment of the present invention.

[0075] refer to Fig.12 The semiconductor structure provided in this embodiment includes: a substrate 300, wherein the substrate 300 has a dielectric layer 301, wherein the dielectric layer 301 has a metal copper layer 303, and the dielectric layer 301 exposes the upper surface of the metal copper layer 303; a contact layer 306, wherein the contact layer 306 is located on the upper surface of the metal copper layer 303, and the material of the contact layer 306 contains cuprous ions; and a barrier layer 307, wherein the barrier layer 307 is located on the upper surface of the contact layer 306, and the material of the barrier layer 307 contains the same element as the material of the contact layer 306.

[0076] The material of the substrate 300 includes sapphire, silicon, silicon carbide, gallium arsenide, aluminum nitride or zinc oxide, etc. In this embodiment, the substrate 300 is made of silicon.

[0077] The material of the dielectric layer 301 may be silicon oxide or a high dielectric material. The high dielectric material may specifically be a ferroelectric ceramic material, a barium titanate material or a lead titanate material.

[0078] The metal copper layer 303 is a conductive layer and can be used as a gate of a semiconductor structure.

[0079] The semiconductor structure provided in this embodiment further includes a buffer layer 304 , and the buffer layer 304 is located between the dielectric layer 301 and the barrier layer 307 .

[0080] A buffer layer 304 is formed between the dielectric layer 301 and the barrier layer 307. Because the contact layer 306 contains cuprous ions, in order to prevent the two sides of the contact layer 306 from contacting and conducting with other structures in the semiconductor structure, the buffer layer 304 is formed on both sides of the contact layer 306 to achieve isolation and insulation, which is beneficial to improving the safety of the semiconductor structure.

[0081] The material of the buffer layer 304 can be silicon nitride or silicon oxide, etc. The thickness of the buffer layer 304 is 5 nanometers to 10 nanometers, specifically 6 nanometers, 7 nanometers or 8 nanometers. The buffer layer 304 only needs to play the role of isolation and insulation, so the thickness of the formed buffer layer 304 is relatively small, which is conducive to saving the production cost of the semiconductor structure.

[0082] The material of the contact layer 306 contains cuprous ions, specifically cuprous thiocyanate. Because the contact layer 306 contains cuprous ions, which has similar chemical properties to the metal copper layer 303, the contact layer 306 formed on the upper surface of the metal copper layer 303 has good adhesion to the metal copper layer 303, and there is no gap between the metal copper layer 303 and the contact layer 306.

[0083] In this embodiment, the thickness of the contact layer 306 is 5 nanometers to 10 nanometers, and specifically may be 6 nanometers, 7 nanometers, or 8 nanometers; and the upper surface of the buffer layer 304 is flush with the upper surface of the contact layer 306 .

[0084] This indicates that the thickness of the contact layer 306 is the same as that of the buffer layer 304, and the upper surface of the contact layer 306 forms a uniform, flat surface with the upper surface of the buffer layer 304, which is conducive to the subsequent deposition to form a barrier layer. Moreover, the contact layer 306 only needs to connect the metal copper layer 303 and the barrier layer, so the thickness of the formed contact layer 306 is relatively small, which is conducive to saving the production cost of the semiconductor structure.

[0085] The material of the barrier layer 307 and the material of the contact layer 306 contain the same elements. Specifically, the material of the barrier layer 307 may be silicon carbonitride. In other embodiments, the material of the barrier layer may be tantalum compounds such as tantalum nitride.

[0086] Because the material of the contact layer 306 and the material of the barrier layer 307 contain the same elements, the contact layer 306 and the barrier layer 307 also have similar chemical properties and good adhesion between the two. There is no gap between the barrier layer 307 and the contact layer 306. It can be obtained that the opposite sides of the contact layer 306 are tightly bonded to the metal copper layer 303 and the barrier layer 307 respectively, and there is no gap or protrusion between the metal copper layer 303 and the barrier layer 307, thereby improving the contact performance between the metal copper layer 303 and the barrier layer 307.

[0087] In this embodiment, the semiconductor structure further includes a metal layer 309 , the metal layer 309 penetrates the barrier layer 307 and the contact layer 306 , and the metal layer 309 contacts the upper surface of the metal copper layer 303 .

[0088] The material of the metal layer 309 includes: tungsten metal, copper metal, aluminum metal, gold metal or silver metal. The gas used to form the metal layer 309 made of tungsten metal includes silane and tungsten hexafluoride. In other embodiments, tungsten metal can also be made of diboron hexahydride and tungsten hexafluoride.

[0089] The semiconductor structure provided in this embodiment has a contact layer between the metal copper layer and the barrier layer, the material of the contact layer contains cuprous ions, and the material of the contact layer and the material of the barrier layer contain the same element. Because the contact layer contains cuprous ions and has similar chemical properties to the metal copper layer, the contact layer on the upper surface of the metal copper layer has good adhesion to the metal copper layer, and there is no gap between the metal copper layer and the contact layer; at the same time, because the material of the contact layer and the material of the barrier layer contain the same element, the contact layer and the barrier layer also have similar chemical properties, and there is good adhesion between the two. In summary, the contact layer is tightly bonded to the metal copper layer and the barrier layer on opposite sides, and there is no gap or protrusion between the metal copper layer and the barrier layer, which improves the contact performance between the metal copper layer and the barrier layer.

[0090] Those skilled in the art will appreciate that the above embodiments are specific examples of the present invention, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present invention. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present invention, and therefore the scope of protection of the present invention shall be subject to the scope defined in the claims.

Claims

1. A method for forming a semiconductor structure, characterized in that: include: Providing a substrate, on which a dielectric layer is disposed, wherein the dielectric layer has a groove; forming a metal copper layer filling the trench; forming a contact layer on the upper surface of the metal copper layer, wherein the material of the contact layer contains cuprous ions; forming a barrier layer on the upper surface of the contact layer, wherein the material of the barrier layer and the material of the contact layer contain the same element; Wherein, the material of the contact layer includes cuprous thiocyanate, and the material of the barrier layer includes silicon carbonitride.

2. The method for forming a semiconductor structure according to claim 1, wherein: The steps of forming the contact layer are: forming an initial contact layer by a spin coating process; and performing a heat treatment on the initial contact layer to form the contact layer.

3. The method for forming a semiconductor structure according to claim 2, wherein: The spin coating process includes: during the spin coating, the substrate, the dielectric layer and the metal copper layer rotate at a rate of 500-3000 revolutions per minute.

4. The method for forming a semiconductor structure according to claim 2, wherein: The heat treatment process includes: when the initial contact layer is heat treated, the process temperature is 70 degrees Celsius to 80 degrees Celsius; the process time is 10 minutes to 20 minutes.

5. The method for forming a semiconductor structure according to claim 1, wherein: Before forming the contact layer, the method further includes: forming a buffer layer on the upper surface of the dielectric layer and the upper surface of the metal copper layer; and etching away a portion of the buffer layer located on the upper surface of the metal copper layer to expose at least the entire upper surface of the metal copper layer.

6. The method for forming a semiconductor structure according to claim 5, characterized in that: After etching away a portion of the buffer layer located on the upper surface of the metal copper layer, the contact layer is formed on the entire exposed upper surface of the metal copper layer, and the upper surface of the contact layer is flush with the upper surface of the remaining portion of the buffer layer.

7. The method for forming a semiconductor structure according to claim 6, wherein: Forming the barrier layer includes: forming the barrier layer on an upper surface of the contact layer and an upper surface of a remaining portion of the buffer layer.

8. The method for forming a semiconductor structure according to claim 1, wherein: After forming the barrier layer, the method further includes: forming a metal layer penetrating the barrier layer and the contact layer, wherein the metal layer contacts the upper surface of the metal copper layer.

9. The method for forming a semiconductor structure according to claim 8, characterized in that: Forming the metal layer includes: etching and removing part of the barrier layer and part of the contact layer to expose part of the upper surface of the metal copper layer; and forming the metal layer on the exposed part of the upper surface of the metal copper layer.

10. A semiconductor structure, characterized in that: include: A substrate, wherein the substrate has a dielectric layer, the dielectric layer has a metal copper layer in it, and the dielectric layer exposes the upper surface of the metal copper layer; A contact layer, the contact layer is located on the upper surface of the metal copper layer, and the material of the contact layer contains cuprous ions; a barrier layer, the barrier layer being located on the upper surface of the contact layer, and the material of the barrier layer and the material of the contact layer containing the same elements; Wherein, the material of the contact layer includes cuprous thiocyanate, and the material of the barrier layer includes silicon carbonitride.

11. The semiconductor structure according to claim 10, characterized in that: Also includes: A buffer layer is located between the dielectric layer and the barrier layer, and an upper surface of the buffer layer is flush with an upper surface of the contact layer.

12. The semiconductor structure according to claim 11, characterized in that: The thickness of the contact layer is 5 nanometers to 10 nanometers.

13. The semiconductor structure according to claim 11, characterized in that: The thickness of the buffer layer is 5 nanometers to 10 nanometers.

14. The semiconductor structure according to claim 10, characterized in that Also includes: A metal layer penetrates the barrier layer and the contact layer, and the metal layer contacts the upper surface of the metal copper layer.

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