Semiconductor structure and preparation method
By forming a transition layer with a smaller dielectric constant in the semiconductor structure, the problem of poor bonding ability between the nitrogen-doped silicon carbide film and the metal is solved, and the effects of reducing delamination and improving device stability are achieved.
Patent Information
- Application Number
- CN202310873781.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-14
- Publication Date
- 2025-01-14
AI Technical Summary
The existing nitrogen-doped silicon carbide film has poor bonding ability to metal, resulting in stratification and affecting the stability of the device.
By forming a first dielectric layer on one side of the substrate, etching to form a channel and filling it with metal, and then introducing silicon-containing carbon and nitrogen-containing gas to react under a specific flow ratio to form a first transition layer with a smaller dielectric constant. to block metal diffusion and improve adhesion.
Effectively reduce the occurrence of delamination, improve device stability, and reduce signal delay.
Smart Images
Figure CN119314945A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a semiconductor structure and a preparation method thereof. Background Art
[0002] In traditional semiconductor processes, in order to form a semiconductor interconnection structure, metal is generally used as the interconnection material of the semiconductor interconnection structure. In order to prevent the diffusion of the metal from affecting the stability of the semiconductor structure, a dielectric barrier layer needs to be provided to block the diffusion of the metal.
[0003] The dielectric barrier layer can be prepared using nitrogen-doped silicon carbide (NDC) thin film material. However, since the existing nitrogen-doped silicon carbide film and metal have different compositions, there are certain differences in mechanical properties, surface energy, interface energy and thermal expansion coefficient. This will lead to poor bonding between the nitrogen-doped silicon carbide film and the metal, resulting in delamination, which greatly affects the stability of the device and even causes the device to fail. Summary of the invention
[0004] In view of this, this summary of the invention is provided to introduce the concepts in a brief form, which will be described in detail in the detailed description section below. This summary of the invention is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to be used to limit the scope of the technical solution claimed for protection.
[0005] The purpose of the present application is to provide a semiconductor structure and a preparation method, which can reduce the occurrence of delamination and improve the stability of the device.
[0006] To achieve the above purpose, this application has the following technical solutions:
[0007] In a first aspect, an embodiment of the present application provides a method for preparing a semiconductor structure, comprising:
[0008] Providing a substrate; forming a first dielectric layer on one side of the substrate;
[0009] Etching the first dielectric layer to form a first channel penetrating the first dielectric layer;
[0010] filling the first channel with a first metal;
[0011] A first reaction gas is introduced at a first flow rate, and a second reaction gas is introduced at a second flow rate to form a first transition layer on a side of the first metal and the first dielectric layer away from the substrate; the first reaction gas includes a silicon-carbon-containing gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio, and the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas.
[0012] In a possible implementation, the method further includes:
[0013] The first reaction gas is introduced at a third flow rate, and the second reaction gas is introduced at a fourth flow rate, so as to form a second transition layer on a side of the first transition layer away from the substrate; the ratio of the third flow rate to the fourth flow rate is a second flow rate ratio; and the second flow rate ratio is greater than the first flow rate ratio;
[0014] forming a second dielectric layer on a side of the second transition layer away from the substrate, wherein the second dielectric layer contains carbon elements;
[0015] Etching the second dielectric layer to form a second channel penetrating the second dielectric layer to expose the surface of the second transition layer;
[0016] The second channel is filled with a second metal.
[0017] In a possible implementation manner, before the first reaction gas is introduced at the third flow rate and the second reaction gas is introduced at the fourth flow rate, the method further includes:
[0018] The first reaction gas is introduced at a fifth flow rate, and the second reaction gas is introduced at a sixth flow rate to form a third transition layer between the first transition layer and the second transition layer; the ratio of the fifth flow rate to the sixth flow rate is a third flow ratio; the third flow ratio is greater than the first flow ratio, and the third flow ratio is less than the second flow ratio.
[0019] In a possible implementation, the first flow rate is smaller than the fifth flow rate, the fifth flow rate is smaller than the third flow rate, the second flow rate is smaller than the sixth flow rate, and the sixth flow rate is smaller than the fourth flow rate.
[0020] In a possible implementation, the first flow ratio range is (0, 0.11], the second flow ratio range is [0.22, 0.35], and the third flow ratio range is (0.11, 0.22).
[0021] In a possible implementation, the first reaction gas includes methylsilane gas, and the second reaction gas includes ammonia and / or hydrazine.
[0022] In a second aspect, an embodiment of the present application provides a semiconductor structure using the semiconductor structure preparation method as described above, comprising:
[0023] A substrate, and a first dielectric layer located on a surface of the substrate;
[0024] A first channel, penetrating the first dielectric layer;
[0025] a first metal disposed in the first channel;
[0026] The first transition layer is located on a side of the first metal and the first dielectric layer away from the substrate; the carbon-nitrogen ratio in the first transition layer is less than or equal to a second preset value, and the second preset value is used to reflect the carbon-nitrogen ratio in the first transition layer.
[0027] In a possible implementation, the method further includes:
[0028] A second transition layer is located on a side of the first transition layer away from the substrate, wherein a carbon-nitrogen ratio in the first transition layer is smaller than a carbon-nitrogen ratio in the second transition layer;
[0029] A second dielectric layer, located on a side of the second transition layer away from the substrate, wherein the second dielectric layer includes carbon elements;
[0030] a second channel, penetrating the second dielectric layer;
[0031] A second metal is located in the second channel.
[0032] In a possible implementation, the method further includes:
[0033] The third transition layer is located between the second transition layer and the first transition layer; the carbon-nitrogen ratio in the third transition layer is smaller than the carbon-nitrogen ratio in the second transition layer, and larger than the carbon-nitrogen ratio in the first transition layer.
[0034] In a possible implementation manner, along a direction from the first transition layer to the second transition layer, a carbon-nitrogen ratio in the third transition layer gradually increases.
[0035] Compared with the prior art, the embodiments of the present application have the following beneficial effects:
[0036] The embodiment of the present application provides a semiconductor structure and a preparation method, the method comprising: providing a substrate; forming a first dielectric layer on one side of the substrate; etching the first dielectric layer to form a first channel penetrating the first dielectric layer; filling the first metal in the first channel as an interconnect metal of the interconnect structure. A first reaction gas is introduced at a first flow rate, and a second reaction gas is introduced at a second flow rate to form a first transition layer on the side of the first metal and the first dielectric layer away from the substrate. The dielectric constant of the first transition layer is relatively small, which can effectively reduce the signal delay caused by the charging and discharging process of the resistor-controlled capacitor in the integrated circuit. The first reaction gas includes a silicon-carbon-containing gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio; the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas. Thus, a first transition layer containing more nitrogen is formed, which can effectively block the diffusion of the first metal. At the same time, the first transition layer contains more nitrogen, and the hardness is relatively large, and has a large surface free energy, which can improve adhesion and reduce the occurrence of stratification. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0038] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.
[0039] Figure 1 A flow chart of a semiconductor structure preparation method provided by an embodiment of the present application is shown;
[0040] Figure 2 A schematic diagram of a semiconductor structure provided by an embodiment of the present application is shown;
[0041] Figure 3 A schematic diagram of another semiconductor structure provided by an embodiment of the present application is shown;
[0042] Figure 4 A schematic diagram of another semiconductor structure provided by an embodiment of the present application is shown;
[0043] Figure 5 A schematic diagram of another semiconductor structure provided by an embodiment of the present application is shown;
[0044] Figure 6 A schematic diagram of another semiconductor structure provided by an embodiment of the present application is shown;
[0045] Figure 7 A schematic diagram of another semiconductor structure provided by an embodiment of the present application is shown;
[0046] Figure 8 A schematic diagram of another semiconductor structure provided in an embodiment of the present application is shown. DETAILED DESCRIPTION
[0047] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.
[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.
[0049] As described in the related art, in traditional semiconductor processes, in order to form a semiconductor interconnect structure, metal is generally used as the interconnect material of the semiconductor interconnect structure. In order to prevent the diffusion of the metal from affecting the stability of the semiconductor structure, a dielectric barrier layer needs to be provided to block the diffusion of the metal.
[0050] The dielectric barrier layer can be prepared using nitrogen-doped silicon carbide (NDC) thin film material. However, since the existing nitrogen-doped silicon carbide film and metal have different compositions, there are certain differences in mechanical properties, surface energy, interface energy and thermal expansion coefficient. This will lead to poor bonding between the nitrogen-doped silicon carbide film and the metal, resulting in delamination, which greatly affects the stability of the device and even causes the device to fail.
[0051] Therefore, how to reduce the delamination phenomenon between nitrogen-doped silicon carbide film and metal and improve the stability of the device is a technical problem that needs to be solved in this field.
[0052] The existing method to solve the above problem is to form a SiN film by reacting SiH4 with NH3, and then depositing an NDC film, so that the SiN film can enhance the bonding ability between Cu and the NDC film and avoid the occurrence of stratification.
[0053] However, SiH4 reacts very easily with Cu to form an alloy. Specifically, SiH4 begins to decompose on the 111 face of Cu, and the decomposition product is SiH3. SiH3 will be adsorbed on the metal vacancies of the FCC (face-centered cubic lattice) of the Cu (111) face, which will also lead to a decrease in the performance of the final device.
[0054] Based on the above technical problems, the embodiment of the present application provides a semiconductor structure and a preparation method, which includes: providing a substrate; forming a first dielectric layer on one side of the substrate; etching the first dielectric layer to form a first channel penetrating the first dielectric layer; filling the first metal in the first channel as the interconnection metal of the interconnection structure. A first reaction gas is introduced at a first flow rate, and a second reaction gas is introduced at a second flow rate to form a first transition layer on one side of the first metal and the first dielectric layer. The dielectric constant of the first transition layer is relatively small, which can effectively reduce the signal delay caused by the charging and discharging process of the resistor-controlled capacitor in the integrated circuit. The first reaction gas includes a silicon-carbon gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio; the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas. Thus, a first transition layer containing more nitrogen is formed, which can effectively block the diffusion of the first metal. At the same time, the first transition layer contains more nitrogen, and the hardness is relatively large, and it has a large surface free energy, which can improve adhesion and reduce the occurrence of stratification.
[0055] In order to better understand the technical solution and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.
[0056] Exemplary Methods
[0057] See also Figure 1 As shown, Figure 1 A flowchart of a method for preparing a semiconductor structure provided in an embodiment of the present application includes:
[0058] S101: providing a substrate; and forming a first dielectric layer on one side of the substrate.
[0059] S102: etching the first dielectric layer to form a first channel penetrating the first dielectric layer;
[0060] S103: Filling the first channel with a first metal.
[0061] In the examples of this application, see Figure 2 Shown is a schematic diagram of a semiconductor structure provided in an embodiment of the present application.
[0062] Specifically, the first dielectric layer 2 can be formed on a substrate 1, and the substrate 1 can be a semiconductor substrate, such as a Si substrate, a Ge substrate, a SiGe substrate, SOI (Silicon On Insulator) or GOI (Germanium On Insulator), etc. In other embodiments, the semiconductor substrate can also be a substrate including other element semiconductors or compound semiconductors, such as GaAs, InP or SiC, etc., and can also be a stacked structure, such as Si / SiGe, etc., and can also be other epitaxial structures, such as SGOI (Silicon Germanium On Insulator), etc. In this embodiment, the substrate 1 is a bulk silicon substrate.
[0063] The first dielectric layer 2 may be made of insulating material. For example, the material of the first dielectric layer 2 may include at least one of a silicon oxide layer, a silicon nitride layer and a silicon oxynitride layer. Optionally, in this embodiment, the first dielectric layer 2 is a carbon-containing silicon oxide layer (Black Diamond, BD2).
[0064] In order to form a subsequent interconnection structure, the embodiment of the present application can etch the first dielectric layer 2 to form a channel 31 penetrating the first dielectric layer 2 . The channel 31 penetrates the first dielectric layer 2 along the thickness direction to expose the upper surface of the substrate 1 .
[0065] Optionally, the channel 31 may include a through hole or a groove, which is not specifically limited in the embodiment of the present application and may be specifically set by those skilled in the art according to the shape of the actual interconnection structure.
[0066] Then, the first metal 3 is filled in the first channel 31 as an interconnection metal in the semiconductor process. Optionally, the first metal 3 may include metals with good electrical conductivity such as aluminum, copper, tungsten, and molybdenum. With the reduction of process nodes, the use of aluminum as a metal interconnection material will lead to a more serious RC delay phenomenon (signal delay caused by the charging and discharging process of the capacitor (C) controlled by the resistor (R) in the integrated circuit). Therefore, the embodiment of the present application preferably uses copper as the interconnection metal. Incorporating copper technology into the integrated circuit manufacturing process can improve the integration of the chip, increase device density, and reduce energy consumption.
[0067] Specifically, the first metal 3 may be deposited by using thin film deposition techniques such as atomic layer deposition (ALD), chemical vapor deposition (CVD), and physical vapor deposition (PVD).
[0068] See also Figure 3, which is a schematic diagram of another semiconductor structure provided by an embodiment of the present application, the first metal 3 can be deposited in the first channel 31 and on the side of the first dielectric layer 2 away from the substrate 1. Figure 4 As shown, it is a schematic diagram of another semiconductor structure provided in an embodiment of the present application. After the deposition is completed, the formed structure can be planarized by a chemical mechanical polishing (CMP) process to grind away the excess first metal 3 located above the first dielectric layer 2.
[0069] S104: introducing a first reaction gas at a first flow rate, and introducing a second reaction gas at a second flow rate, so as to form a first transition layer on the side of the first metal and the first dielectric layer away from the substrate; the first reaction gas includes a silicon-carbon-containing gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio, and the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas.
[0070] In the examples of this application, see Figure 5 , which is a schematic diagram of another semiconductor structure provided by an embodiment of the present application, can react on one side of the first metal 3 and the first dielectric layer 2 to generate a first transition layer 41. Specifically, the first transition layer 41 is formed on the side of the first metal 3 and the first dielectric layer 2 away from the substrate 1.
[0071] Specifically, in order to form the first transition 41, the embodiment of the present application may introduce a first reaction gas at a first flow rate, and introduce a second reaction gas at a second flow rate. The first reaction gas includes a silicon-carbon-containing gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio; the first flow rate ratio is less than or equal to a first preset value; and the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas.
[0072] That is, in the embodiment of the present application, the carbon silicon element gas and the nitrogen-containing element gas can be reacted at a certain temperature and pressure to generate a first transition layer 41 as a dielectric barrier layer. The dielectric barrier layer needs to block the diffusion of the first metal 3 and reduce the stratification phenomenon between the first metal 3 and the dielectric barrier layer, that is, the adhesion of the dielectric barrier layer must also be good to ensure the good electrical properties of the final device, so that the device has better electromigration (EM) performance and time-dependent dielectric breakdown (TDDB) performance.
[0073] Specifically, since the properties of the dielectric barrier layer material have a great influence on the adhesion of the film, the adhesion is closely related to the surface energy and interface energy of the material.
[0074] Assuming that the surface free energy of the dielectric barrier layer material is δj, and the surface free energy of the film layer material is δm, the adhesion energy between the dielectric barrier layer and the first metal 3 is w=δj+δm-δjm. If the dielectric barrier layer and the first metal 3 are the same material, there is no strain at the interface. For materials with similar crystals, since δjm is small, a larger free energy can be obtained between the two. In addition, high melting point materials or high hardness materials often have larger surface free energy. When the surface free energy is large, the adhesion between the dielectric barrier layer and the first metal 3 is better.
[0075] Therefore, in the embodiment of the present application, the flow ratio of the introduced reaction gas can be controlled to obtain the first transition layer 41 containing more nitrogen, the flow of the carbon-silicon element gas is smaller, and the flow of the nitrogen element gas is larger, because the carbon-nitrogen ratio in the first transition layer 41 is positively correlated with the first flow ratio. Therefore, setting the first flow ratio to be less than or equal to the first preset value can reduce the carbon-nitrogen ratio in the first transition layer 41, and the generated first transition layer 41 is a nitride-like substance.
[0076] When the nitrogen element in the first transition layer 41 increases, the Si-N bond and the NN bond on the film surface increase, the Si-N bond and the NN bond have short bond lengths and large bond energies, and fewer gaps, which can effectively block the diffusion of the first metal 3. At the same time, the increase in the Si-N bond and the NN bond can reduce the hydrogen content, avoiding the Si-H + The increase of silicon-hydrogen bridges and silicon dangling bonds prevents the first metal 3 from migrating through these hydrogen-related sites, thereby resulting in a longer diffusion depth.
[0077] At the same time, since the first transition layer 41 is a nitride-like material, when the nitrogen element increases, the hardness of the first transition layer 41 can be improved. The increased hardness has a larger surface free energy, which can improve adhesion and reduce the occurrence of delamination.
[0078] In one possible implementation, see Figure 6 FIG. 1 is a schematic diagram of another semiconductor structure provided in an embodiment of the present application. The method for preparing the semiconductor structure provided in an embodiment of the present application may further include:
[0079] The first reaction gas is introduced at a third flow rate, and the second reaction gas is introduced at a fourth flow rate to react on the side of the first transition layer 41 away from the first dielectric layer 2 to generate the second transition layer 42; the ratio of the third flow rate to the fourth flow rate is the second flow rate ratio; the second flow rate ratio is greater than the first flow rate ratio.
[0080] That is, in the embodiment of the present application, the carbon silicon element gas and the nitrogen-containing element gas can be reacted at a certain temperature and pressure to generate the second transition layer 42 and the first transition layer 41 as a dielectric barrier layer. In the embodiment of the present application, the nitrogen-doped silicon carbide material is used as the dielectric barrier layer. The dielectric constant K value of the nitrogen-doped silicon carbide is small, K is less than 5, which is smaller than the K value of silicon nitride as the dielectric barrier layer (the K value of silicon nitride is equal to 7), which can reduce the RC delay phenomenon.
[0081] In addition, in the examples of this application, see Figure 7 FIG. 1 is a schematic diagram of another semiconductor structure provided by an embodiment of the present application. In order to form a complete semiconductor structure, a second dielectric layer 5 may be formed on the side of the second transition layer 42 away from the first dielectric layer 2; the second dielectric layer 5 contains carbon; the second dielectric layer 5 is etched to form a second channel 32 penetrating the second dielectric layer 5 to expose the surface of the second transition layer 42; and the second metal 6 is filled in the second channel 32.
[0082] The material and preparation process of the second dielectric layer 5 may be the same or different from that of the first dielectric layer 2, and the material and preparation process of the second metal 6 may be the same or different from that of the first metal 3. The embodiments of the present application will not be described in detail here, and the specific configuration may be made by those skilled in the art according to actual conditions.
[0083] Optionally, the second dielectric layer 5 contains carbon elements, such as a carbon-containing silicon dioxide film, a carbon-containing silicon oxynitride film, etc. Since the carbon-nitrogen ratio in the second transition layer 42 is positively correlated with the second flow ratio. Therefore, setting the second flow ratio to be greater than the first flow ratio can increase the carbon-nitrogen ratio in the second transition layer 42, and the generated second transition layer 42 is a carbide-like material. Since the second transition layer 42 and the second dielectric layer 5 both contain carbon elements as similar materials, the two can obtain greater free energy, which can enhance the adhesion between the two and reduce the occurrence of stratification.
[0084] In one possible implementation, see Figure 8 FIG. 2 is a schematic diagram of another semiconductor structure provided in an embodiment of the present application. Before the first reaction gas is introduced at a third flow rate and the second reaction gas is introduced at a fourth flow rate, the method provided in an embodiment of the present application may further include:
[0085] The first reaction gas is introduced at a fifth flow rate and the second reaction gas is introduced at a sixth flow rate to form a third transition layer 43 between the first transition layer 41 and the second transition layer 42; the ratio of the fifth flow rate to the sixth flow rate is a third flow ratio; the third flow ratio is greater than the first flow ratio, and the third flow ratio is less than the second flow ratio.
[0086] Specifically, in the embodiment of the present application, since the carbon-nitrogen ratio in the third transition layer 42 is positively correlated with the third flow ratio, the third flow ratio is set to be greater than the first flow ratio and less than the second flow ratio. The carbon-nitrogen ratio in the third transition layer 43 can be relatively balanced, thereby forming a third transition layer 43 containing relatively balanced carbon and nitrogen. As a transition layer, the sudden change of carbon and nitrogen content can be avoided, and the occurrence of stratification can be further reduced. The stability of the structure is improved.
[0087] In a possible implementation, the value of the third flow ratio may be gradually increased in the direction from the first transition layer 41 to the second transition layer 42, so that the carbon-nitrogen ratio in the third transition layer 43 gradually increases. Thus, the carbon-nitrogen ratio in the third transition layer 43 is adjusted to a gradual form, which can better match the first transition layer 41 and the second transition layer 42, increase the adhesion between the third transition layer 43 and the first transition layer 41, and increase the adhesion between the third transition layer 43 and the second transition layer 42.
[0088] Optionally, the first flow rate provided in the embodiment of the present application is smaller than the fifth flow rate; the fifth flow rate is smaller than the third flow rate; the second flow rate is smaller than the sixth flow rate; and the sixth flow rate is smaller than the fourth flow rate.
[0089] That is, in the embodiment of the present application, the flow rate of the reaction gas for the nitrogen-doped silicon carbide layer can be gradually increased, and the reaction rate can be gradually increased to improve the preparation efficiency of the semiconductor structure.
[0090] Specifically, the first transition layer 41 is prepared at a slow speed and can be prepared by fine processes such as ALD to improve compactness and effectively block metal diffusion. The second transition layer 42 is prepared at a fast speed and can be prepared by CVD to obtain a thicker film in a short time, effectively blocking metal diffusion through the film thickness. The third transition layer 43 is prepared at a moderate speed and can be used as a transition to avoid adverse effects caused by sudden changes, which is more in line with the needs of actual process preparation.
[0091] Optionally, the first flow ratio range provided in the embodiment of the present application is (0, 0.11], the second flow ratio range is [0.22, 0.35], and the third flow ratio range is (0.11, 0.22).
[0092] Optionally, the carbon-silicon element gas provided in the embodiment of the present application may include methylsilane gas, such as trimethylsilane, tetramethylsilane, trichloromethylsilane, etc. The nitrogen-containing element gas may include ammonia and / or hydrazine, etc. In particular, when tetramethylsilane gas and ammonia are used as reaction gases for preparation, the above flow ratio may be used to pass into the reaction chamber.
[0093] Optionally, the first flow rate provided in the embodiment of the present application may be [100sccm, 300sccm], the second flow rate may be [1000sccm, 2000sccm], the third flow rate may be [350sccm, 650sccm], the fourth flow rate may be [1500sccm, 3000sccm], the fifth flow rate may be [650sccm, 850sccm], and the sixth flow rate may be [2500sccm, 4000sccm].
[0094] Optionally, the reaction pressure provided in the embodiment of the present application can be [1 torr, 3 torr], and the reaction temperature can be [350° C., 400° C.] to achieve sufficient reaction of the reaction gas.
[0095] It should be noted that the material of the first transition layer 41, the second transition layer 42 and / or the third transition layer 43 provided in the above-mentioned embodiment of the present application may include nitrogen-doped silicon carbide.
[0096] The embodiment of the present application provides a method for preparing a semiconductor structure, the method comprising: providing a substrate; forming a first dielectric layer on one side of the substrate; etching the first dielectric layer to form a first channel penetrating the first dielectric layer; filling the first metal in the first channel as the interconnection metal of the interconnection structure. A first reaction gas is introduced at a first flow rate, and a second reaction gas is introduced at a second flow rate to form a first transition layer on one side of the first metal and the first dielectric layer. The dielectric constant of the first transition layer is relatively small, which can effectively reduce the signal delay caused by the charging and discharging process of the resistor-controlled capacitor in the integrated circuit. The first reaction gas includes a silicon-carbon gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio; the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas. Thus, a first transition layer containing more nitrogen is formed, which can effectively block the diffusion of the first metal. At the same time, the first transition layer contains more nitrogen, and the hardness is relatively large, and has a large surface free energy, which can improve adhesion and reduce the occurrence of delamination.
[0097] Exemplary Structure
[0098] See also Figure 5 FIG. 1 is a schematic diagram of a semiconductor structure provided in an embodiment of the present application, which can be prepared by the method described above, including:
[0099] A substrate 1, and a first dielectric layer 2 located on a surface of the substrate 1;
[0100] The first channel 31 penetrates the first dielectric layer 2; the first metal 3 is located in the first channel 31;
[0101] The first transition layer is located on the side of the first metal 3 and the first dielectric layer 2 away from the substrate 1 ; the carbon-nitrogen ratio in the first transition layer 41 is less than or equal to the second preset value; the second preset value is used to reflect the carbon-nitrogen ratio in the first transition layer 41 .
[0102] Therefore, the carbon-nitrogen ratio in the first transition layer 41 is set to be less than or equal to the second preset value, so that the carbon-nitrogen ratio in the first transition layer 41 can be reduced. At this time, the first transition layer 41 is a nitride-like material.
[0103] When the nitrogen element in the first transition layer 41 increases, the Si-N bond and the NN bond on the film surface increase, the Si-N bond and the NN bond have short bond lengths and large bond energies, and fewer gaps, which can effectively block the diffusion of the first metal 3. At the same time, the increase in the Si-N bond and the NN bond can reduce the hydrogen content, avoiding the Si-H + The increase of silicon-hydrogen bridges and silicon dangling bonds prevents the first metal 3 from migrating through these hydrogen-related sites, thereby resulting in a longer diffusion depth.
[0104] At the same time, since the first transition layer 41 is a nitride-like material, when the nitrogen element increases, the hardness of the first transition layer 41 can be improved. The increased hardness has a larger surface free energy, which can improve adhesion and reduce the occurrence of delamination.
[0105] In one possible implementation, see Figure 7 As shown, a semiconductor structure provided by an embodiment of the present application may also include:
[0106] A second transition layer 42, located on a side of the first transition layer 41 away from the substrate 1; the carbon-nitrogen ratio in the first transition layer 41 is smaller than the carbon-nitrogen ratio in the second transition layer 42;
[0107] The second dielectric layer 5 is located on the side of the second transition layer 42 away from the substrate 1; the second dielectric layer 5 contains carbon elements;
[0108] The second channel 32 penetrates the second dielectric layer 5 ; the second metal 6 is located in the second channel 32 .
[0109] The second transition layer 42 generated at this time is a carbide-like material. Since the second transition layer 42 and the second dielectric layer 5 both contain carbon elements as similar materials, the two can obtain greater free energy, which can enhance the adhesion between the two and reduce the occurrence of delamination.
[0110] In one possible implementation, see Figure 8 As shown, a semiconductor structure provided by an embodiment of the present application may also include:
[0111] The third transition layer 43 is located between the second transition layer 42 and the first transition layer 41 ; the carbon-nitrogen ratio in the third transition layer 43 is smaller than that in the second transition layer 42 , and larger than that in the first transition layer 41 .
[0112] The carbon-nitrogen ratio in the third transition layer 43 is relatively balanced, thus forming a third transition layer 43 containing relatively balanced carbon and nitrogen. As a transition layer, the sudden change of carbon and nitrogen content can be avoided, and the occurrence of stratification can be further reduced, thereby improving the stability of the structure.
[0113] In a possible implementation, the carbon-nitrogen ratio in the third transition layer 43 may be gradually increased in the direction from the first transition layer 41 to the second transition layer 42. Thus, the carbon-nitrogen ratio in the third transition layer 43 is adjusted to a gradual form, which can better match the first transition layer 41 and the second transition layer 42, increase the adhesion between the third transition layer 43 and the first transition layer 41, and increase the adhesion between the third transition layer 43 and the second transition layer 42.
[0114] It should be noted that the material of the first transition layer 41, the second transition layer 42 and / or the third transition layer 43 provided in the above-mentioned embodiment of the present application may include nitrogen-doped silicon carbide.
[0115] The embodiment of the present application provides a semiconductor structure, which includes: a substrate, and a first dielectric layer located on the surface of the substrate; a first channel, which runs through the first dielectric layer; a first metal, which is located in the first channel; a first transition layer, which is located on the side of the first metal and the first dielectric layer away from the substrate; the carbon-nitrogen ratio in the first transition layer is less than or equal to a second preset value, and the second preset value is used to reflect the carbon-nitrogen ratio in the first transition layer. Thus, a first transition layer containing more nitrogen is formed, which can effectively block the diffusion of the first metal. At the same time, the first transition layer contains more nitrogen, and the hardness is also relatively large, and it has a larger surface free energy, which can improve adhesion and reduce the occurrence of stratification.
[0116] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the structural embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.
[0117] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.
Claims
1. A method for preparing a semiconductor structure, characterized in that: include: Providing a substrate; forming a first dielectric layer on one side of the substrate; Etching the first dielectric layer to form a first channel penetrating the first dielectric layer; filling the first channel with a first metal; A first reaction gas is introduced at a first flow rate, and a second reaction gas is introduced at a second flow rate to form a first transition layer on a side of the first metal and the first dielectric layer away from the substrate; the first reaction gas includes a silicon-carbon-containing gas, and the second reaction gas includes a nitrogen-containing gas; the ratio of the first flow rate to the second flow rate is a first flow rate ratio, and the first flow rate ratio is less than or equal to a first preset value; the first preset value is used to reflect the carbon-nitrogen ratio in the reaction gas.
2. The method according to claim 1, characterized in that Also includes: The first reaction gas is introduced at a third flow rate, and the second reaction gas is introduced at a fourth flow rate, so as to form a second transition layer on a side of the first transition layer away from the substrate; the ratio of the third flow rate to the fourth flow rate is a second flow rate ratio; and the second flow rate ratio is greater than the first flow rate ratio; forming a second dielectric layer on a side of the second transition layer away from the substrate, wherein the second dielectric layer contains carbon elements; Etching the second dielectric layer to form a second channel penetrating the second dielectric layer to expose the surface of the second transition layer; The second channel is filled with a second metal.
3. The method according to claim 2, characterized in that Before the first reaction gas is introduced at the third flow rate and the second reaction gas is introduced at the fourth flow rate, the method further includes: The first reaction gas is introduced at a fifth flow rate, and the second reaction gas is introduced at a sixth flow rate to form a third transition layer between the first transition layer and the second transition layer; the ratio of the fifth flow rate to the sixth flow rate is a third flow ratio; the third flow ratio is greater than the first flow ratio, and the third flow ratio is less than the second flow ratio.
4. The method according to claim 3, characterized in that The first flow rate is smaller than the fifth flow rate, the fifth flow rate is smaller than the third flow rate, the second flow rate is smaller than the sixth flow rate, and the sixth flow rate is smaller than the fourth flow rate.
5. The method according to claim 3 or 4, characterized in that: The first flow ratio range is (0, 0.11], the second flow ratio range is [0.22, 0.35], and the third flow ratio range is (0.11, 0.22).
6. The method according to any one of claims 1 to 3, characterized in that The first reaction gas includes methylsilane gas, and the second reaction gas includes ammonia and / or hydrazine.
7. A semiconductor structure, characterized in that: Prepared by the method according to any one of claims 1 to 6, comprising: A substrate, and a first dielectric layer located on a surface of the substrate; A first channel, penetrating the first dielectric layer; a first metal disposed in the first channel; The first transition layer is located on a side of the first metal and the first dielectric layer away from the substrate; the carbon-nitrogen ratio in the first transition layer is less than or equal to a second preset value, and the second preset value is used to reflect the carbon-nitrogen ratio in the first transition layer.
8. The structure according to claim 7, characterized in that Also includes: A second transition layer is located on a side of the first transition layer away from the substrate, wherein a carbon-nitrogen ratio in the first transition layer is smaller than a carbon-nitrogen ratio in the second transition layer; A second dielectric layer, located on a side of the second transition layer away from the substrate, wherein the second dielectric layer includes carbon elements; a second channel, penetrating the second dielectric layer; A second metal is located in the second channel.
9. The structure according to claim 8, characterized in that Also includes: The third transition layer is located between the second transition layer and the first transition layer; the carbon-nitrogen ratio in the third transition layer is smaller than the carbon-nitrogen ratio in the second transition layer, and larger than the carbon-nitrogen ratio in the first transition layer.
10. The structure according to claim 9, characterized in that In a direction from the first transition layer to the second transition layer, the carbon-nitrogen ratio in the third transition layer gradually increases.