Sputtering method
By adopting the target proportion of inert gas mixed gas sputtering and off-axis sputtering technologies in semiconductor manufacturing, the problem of inhomogeneity of nickel-platinum alloy thin films is solved, and the film layer quality and device reliability are improved.
Patent Information
- Application Number
- CN202510810224.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-08-15
AI Technical Summary
In the prior art, the nickel-platinum alloy film is not uniform enough in semiconductor manufacturing, resulting in poor device reliability and high film stress.
The target film layer is formed by sputtering using an inert gas mixed gas whose average molecular weight is close to the target target molecular weight in the target proportion.
Improve the uniformity and quality of the target film layer, reduce film stress, and enhance the reliability of the device.
Smart Images
Figure CN120485707A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular to a sputtering method. Background Art
[0002] In semiconductor technology, physical vapor deposition (PVD) is widely used in thin film fabrication. Methods include vacuum evaporation, sputtering, and molecular beam epitaxy. Among these, sputtering is the most widely used process for metal thin film fabrication.
[0003] The basic principle of sputtering coating is to make argon (Ar) gas glow discharge under vacuum conditions. At this time, argon (Ar) atoms are ionized into argon ions (Ar+). Under the action of the electric field force, they are accelerated to bombard the cathode target made of plating material. The target particles are sputtered out and deposited on the wafer surface. Summary of the Invention
[0004] The problem solved by the embodiments of the present invention is to provide a sputtering method, which is beneficial to improving the uniformity and quality of the target film layer.
[0005] To solve the above problems, an embodiment of the present invention provides a sputtering method, including: providing a substrate; providing a target target material; introducing a mixed gas of multiple inert gases as a working gas according to a target proportion, wherein the difference between the average molecular weight of the mixed gas and the molecular weight of the target target material at the target proportion is less than a preset value; and using the working gas to bombard the target target material for sputtering to form a target film layer on the substrate.
[0006] Optionally, in the step of introducing a mixed gas of multiple inert gases in a target ratio as the working gas, a mixed gas of argon and krypton in a target ratio is introduced as the working gas.
[0007] Optionally, in the step of providing a target target material, the target target material is a nickel-platinum alloy; in the step of introducing a mixed gas of argon and krypton as a working gas according to a target ratio, the proportion of argon is greater than that of krypton.
[0008] Optionally, a working gas is used to bombard a target material for sputtering, and in the step of forming a target film layer on a substrate, the working gas is used to bombard the target material for off-axis sputtering.
[0009] Optionally, a substrate eccentric rotation method is used to bombard a target material with a working gas to perform off-axis sputtering.
[0010] Optionally, before using working gas to bombard the target target material for off-axis sputtering, it also includes: setting the sputtering ring width on the target target material to the target width; setting the eccentric distance between the rotation axis of the substrate and the normal line of the target center to the target eccentric distance; setting the vertical height of the substrate from the target surface to the target target base distance, so that the sputtering incident angle is within the target incident angle range.
[0011] Optionally, the target incident angle range is obtained based on a mapping relationship between the sputtering yield of the target target material and the incident angle.
[0012] Optionally, in the step of providing a target target material, the target target material is a nickel-platinum alloy; in the step of bombarding the target target material with a working gas for sputtering to form a target film layer on a substrate, the nickel-platinum alloy is sputtered with a working gas to form a metal silicide layer on the substrate.
[0013] Optionally, in the step of providing a substrate, the substrate includes a substrate, a gate structure located on the substrate, and a source-drain doped layer located in the substrate on both sides of the gate structure; in the step of using a working gas to bombard a nickel-platinum alloy for sputtering to form a metal silicide layer on the substrate, a metal silicide layer is formed on the top surface of the gate structure and the top surface of the source-drain doped layer.
[0014] Optionally, after the working gas is used to bombard the nickel-platinum alloy for sputtering to form a metal silicide layer on the substrate, the method further includes: annealing the metal silicide layer.
[0015] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages: In the sputtering method provided in an embodiment of the present invention, a mixed gas of multiple inert gases is introduced as a working gas according to a target ratio, wherein the difference between the average molecular weight of the mixed gas at the target ratio and the molecular weight of the target target material is less than a preset value; in an embodiment of the present invention, the difference between the average molecular weight of the mixed gas at the target ratio and the molecular weight of the target target material is less than a preset value, that is, at the target ratio, the average molecular weight of the mixed gas is relatively close to the molecular weight of the target target material. During the sputtering process, the role of the working gas is to bombard the target target material through ions, so that the target target material atoms are sputtered out and deposited on the substrate to form a target film layer. When the molecular weight of the working gas is close to the molecular weight of the target target material, the deposition energy and momentum distribution of the sputtered atoms on the substrate are more uniform, which is beneficial to reducing the stress of the target film layer. Moreover, the molecular weight of the working gas is close to the molecular weight of the target target material, which is beneficial to reducing the uneven distribution of sputtered atom energy caused by quality differences, thereby improving the uniformity and quality of the target film layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a flowchart of steps corresponding to an embodiment of the sputtering method of the present invention; Figures 2 to 6It is a schematic structural diagram corresponding to each step in an embodiment of the sputtering method of the present invention. DETAILED DESCRIPTION
[0017] As can be seen from the background technology, in semiconductor manufacturing technology, metal silicide is widely used in source-drain contacts and gate contacts to reduce contact resistance due to its low resistivity and good adhesion to other materials. With the improvement of semiconductor process level, in order to obtain lower contact resistance, nickel and nickel alloys have become the main materials for forming metal silicide. In the prior art, in order to improve the consistency of the film formed by sputtering, it is generally formed by sputtering deposition at a lower power. However, the metal film formed at a lower power is still not uniform enough, and the alloy element content in the central area of the silicon wafer is lower than that in the peripheral area. Therefore, devices with thicker nickel-platinum alloy film thickness will experience nickel element diffusion, resulting in poor reliability of the device.
[0018] In order to solve the technical problem, an embodiment of the present invention provides a sputtering method. Figure 1 is a flow chart of steps corresponding to an embodiment of the sputtering method of the present invention, refer to Figure 1 , sputtering methods include: Step S1: providing a substrate; Step S2: providing a target material; Step S3: introducing a mixed gas of multiple inert gases in a target ratio as a working gas, wherein the difference between the average molecular weight of the mixed gas and the molecular weight of the target material at the target ratio is less than a preset value; Step S4: using working gas to bombard the target material for sputtering, thereby forming a target film layer on the substrate.
[0019] In an embodiment of the present invention, the difference between the average molecular weight of the mixed gas and the molecular weight of the target target material at the target ratio is less than a preset value, that is, at the target ratio, the average molecular weight of the mixed gas is relatively close to the molecular weight of the target target material. During the sputtering process, the role of the working gas is to bombard the target target material through ions, so that the target target material atoms are sputtered out and deposited on the substrate to form a target film layer. When the molecular weight of the working gas is close to the molecular weight of the target target material, the deposition energy and momentum distribution of the sputtered atoms on the substrate are more uniform, which is beneficial to reducing the stress of the target film layer. Moreover, the molecular weight of the working gas is close to the molecular weight of the target target material, which is beneficial to reducing the uneven distribution of sputtered atom energy caused by mass differences, thereby improving the uniformity and quality of the target film layer.
[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0021] Figures 2 to 6 It is a schematic structural diagram corresponding to each step in an embodiment of the sputtering method of the present invention.
[0022] refer to Figure 2 , perform step S1: provide a substrate 100.
[0023] The substrate 100 is an operating platform for performing a sputtering process.
[0024] refer to Figure 3 In the step of providing a substrate 100 , the substrate 100 includes a substrate 110 , a gate structure 120 located on the substrate 110 , and source / drain doped layers 130 located in the substrate 110 on both sides of the gate structure 120 .
[0025] The substrate 110 , the gate structure 120 , and the source-drain doped layer 130 are basic semiconductor structures constituting a transistor, wherein the gate structure 120 is used to control the opening and closing of the channel, and the source-drain doped layer 130 is used as the source region and the drain region of the transistor.
[0026] refer to Figure 4 , executing step S2: providing a target material 200 .
[0027] The target material 200 is a key material in the sputtering process. During the sputtering process, atoms or molecules of the target material 200 are removed and transferred to the surface of the substrate 100 through high-energy ion bombardment, forming a thin film with specific functions. The selection and use of the target material 200 are determined based on the desired film performance, quality, and application range.
[0028] In this embodiment, the target material 200 is made of a variety of materials, including metals, alloys, ceramics, and compounds. Each material has specific properties and applications. For example, metal targets (such as copper, aluminum, and titanium) are used to fabricate conductive and reflective films, while ceramic and compound targets (such as aluminum oxide and titanium oxide) are used to fabricate insulating and optical films.
[0029] As an example, in this embodiment, in the step of providing the target material 200 , the target material 200 is a nickel-platinum alloy.
[0030] Using nickel-platinum alloy as the target material 200 is beneficial for the film formed by sputtering to have better high-temperature oxidation resistance and stability, and is also beneficial for the film formed by sputtering to obtain lower contact resistance.
[0031] As an example, in this embodiment, in the step of providing the target material 200 , the proportion of platinum in the nickel-platinum alloy is generally 5%.
[0032] refer to Figure 5, executing step S3: introducing a mixed gas of multiple inert gases as a working gas according to a target ratio, wherein the difference between the average molecular weight of the mixed gas at the target ratio and the molecular weight of the target material 200 is less than a preset value.
[0033] A mixed gas of multiple inert gases is introduced as a working gas for subsequent ion bombardment of the target material 200 , so that atoms of the target material 200 are sputtered out and deposited on the substrate 100 to form a thin film.
[0034] In this embodiment, the difference between the average molecular weight of the mixed gas at the target ratio and the molecular weight of the target target material 200 is less than a preset value, that is, at the target ratio, the average molecular weight of the mixed gas is relatively close to the molecular weight of the target target material 200. During the sputtering process, the role of the working gas is to bombard the target target material 200 through ions, so that the atoms of the target target material 200 are sputtered out and deposited on the substrate 100 to form a target film layer. When the molecular weight of the working gas is close to the molecular weight of the target target material 200, the deposition energy and momentum distribution of the sputtered atoms on the substrate 100 are more uniform, which is beneficial to reducing the stress of the target film layer. Moreover, the molecular weight of the working gas is close to the molecular weight of the target target material 200, which is beneficial to reducing the uneven distribution of sputtered atom energy caused by quality differences, thereby improving the uniformity and quality of the target film layer.
[0035] In this embodiment, in the step of introducing a mixed gas of multiple inert gases according to a target ratio as the working gas, a mixed gas of argon and krypton according to a target ratio is introduced as the working gas.
[0036] Argon (Ar) is inexpensive, widely available, and has good momentum transfer capabilities, which is beneficial for efficiently sputtering various target materials 200. Krypton (Kr) is beneficial for sputtering heavier elements, which have a larger atomic weight and are beneficial for more effectively transferring momentum to heavy target materials 200.
[0037] In this embodiment, in the step of introducing a mixed gas of argon and krypton as the working gas according to a target ratio, the proportion of argon is greater than the proportion of krypton.
[0038] The proportion of platinum in nickel-platinum alloy is usually small, so the molecular weight of nickel-platinum alloy will not be too large. The proportion of argon gas is greater than that of krypton gas, so that the molecular weight of the working gas will not be too large, thereby making the molecular weight of the working gas closer to the molecular weight of the target material 200 of nickel-platinum alloy. Moreover, argon gas is easier to obtain than krypton gas, which is conducive to the acquisition of working gas.
[0039] As an example, in this embodiment, in the step of introducing a mixed gas of argon and krypton as the working gas according to a target ratio, the ratio of argon to krypton is 2:1.
[0040] It should be noted that, in this embodiment, as the proportion of platinum in the nickel-platinum alloy target material 200 changes, the ratio of argon and krypton in the working gas is also adjusted accordingly.
[0041] Continue to refer Figure 5 , executing step S4: using working gas to bombard the target material 200 for sputtering, to form a target film layer on the substrate 100.
[0042] In this embodiment, the target material 200 is sputtered by bombarding the target gas. In the step of forming the target film layer on the substrate 100, the target material 200 is sputtered by bombarding the target gas by the working gas.
[0043] Off-axis sputtering can optimize the incident angle of sputtered particles by changing the relative position of the target material 200 and the substrate 100, thereby facilitating improvement of the thickness uniformity of the target film layer.
[0044] Specifically, in this embodiment, an eccentric rotation method of the substrate 100 is adopted to bombard the target material 200 with working gas to perform off-axis sputtering.
[0045] The off-axis sputtering method of eccentric rotation can make the sputtered particles of the target material 200 evenly distributed on the substrate 100 by rotating and eccentrically placing the substrate 100, thereby facilitating improving the thickness uniformity of the target film layer.
[0046] In this embodiment, before using working gas to bombard the target target material 200 for off-axis sputtering, it also includes: setting the sputtering ring width on the target target material 200 as the target width; setting the eccentric distance between the rotation axis of the substrate 100 and the normal line of the target center as the target eccentric distance; setting the vertical height of the substrate 100 from the target surface as the target target base distance, so that the sputtering incident angle is within the target incident angle range.
[0047] like Figure 5 As shown, the sputtering ring width on the target target 200 is set to the target width, that is, the sputtering ring on the target target 200 is set to the target width of r1 to r2, the eccentric distance between the rotation axis of the substrate 100 and the normal line of the target center is set to the target eccentricity, that is, the eccentric distance between the rotation axis O2O3 of the substrate 100 and the normal line of the target center O1 is set to the target eccentricity of O1O3, and the vertical height between the substrate 100 and the target surface is set to the target target base distance, that is, the vertical height between the substrate 100 and the target surface is set to the target target base distance O2O3, so that the incident angle θ of a point D on the target target 200 sputtering to a point P on the substrate 100 is within the target incident angle range.
[0048] In this embodiment, the target incident angle range is obtained based on a mapping relationship between the sputtering yield of the target material 200 and the incident angle θ.
[0049] During the off-axis sputtering process, the sputtering yield of the target material 200 first increases and then decreases as the incident angle θ increases. Therefore, based on the mapping relationship between the sputtering yield and the incident angle θ, a certain area where the sputtering yield peaks is obtained as the target incident angle range.
[0050] In this embodiment, the target material 200 is sputtered by bombarding the target gas. In the step of forming the target film layer on the substrate 100, the nickel-platinum alloy is sputtered by bombarding the target gas to form a metal silicide layer on the substrate 100.
[0051] An off-axis sputtering process is adopted, and a mixture of argon and krypton is used as the main gas for ionization and starting the sputtering process. At the target ratio, the average molecular weight of the mixed gas is close to that of the nickel-platinum alloy, which is conducive to the formation of a metal silicide layer with higher uniformity.
[0052] Specifically, refer to Figure 6 In the step of forming a metal silicide layer on the substrate 100 by bombarding the nickel-platinum alloy with a working gas for sputtering, a metal silicide layer 140 is formed on the top surface of the gate structure 120 and the top surface of the source-drain doped layer 130 .
[0053] A metal silicide layer 140 is formed on the top surface of the gate structure 120 and the top surface of the source / drain doped layer 130 to reduce the contact resistance between the gate structure 120 and the external electrical connection and between the source / drain doped layer 130 and the external electrical connection.
[0054] In this embodiment, after the metal silicide layer 140 is formed on the substrate 100 by bombarding the nickel-platinum alloy with a working gas for sputtering, the method further includes: annealing the metal silicide layer 140 .
[0055] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.
Claims
1. A sputtering method, characterized in that: include: providing a substrate; Provide target materials; A mixed gas of multiple inert gases is introduced as a working gas according to a target ratio, wherein the difference between the average molecular weight of the mixed gas and the molecular weight of the target material at the target ratio is less than a preset value; The target material is bombarded with the working gas to perform sputtering, thereby forming a target film layer on the substrate.
2. The sputtering method according to claim 1, wherein In the step of introducing a mixed gas of multiple inert gases according to a target ratio as the working gas, a mixed gas of argon and krypton according to a target ratio is introduced as the working gas.
3. The sputtering method according to claim 1, wherein In the step of providing the target material, the target material is a nickel-platinum alloy; In the step of introducing a mixed gas of argon and krypton as the working gas according to a target ratio, the proportion of the argon gas is greater than the proportion of the krypton gas.
4. The sputtering method according to claim 1, wherein The target material is sputtered by bombarding the target with the working gas. In the step of forming a target film layer on a substrate, the target material is sputtered by bombarding the target with the working gas.
5. The sputtering method according to claim 4, wherein: A substrate eccentric rotation method is adopted to bombard the target material with the working gas to perform off-axis sputtering.
6. The sputtering method according to claim 5, wherein: Before using the working gas to bombard the target material for off-axis sputtering, the method further includes: setting the sputtering ring width on the target material to a target width; Set the eccentric distance between the substrate's rotation axis and the target center normal as the target eccentricity; The vertical height between the substrate and the target surface is set as the target target-substrate distance so that the incident angle of sputtering is within the target incident angle range.
7. The sputtering method according to claim 6, wherein: The target incident angle range is obtained based on a mapping relationship between the sputtering yield of the target target material and the incident angle.
8. The sputtering method according to claim 1, wherein In the step of providing a target material, the target material is a nickel-platinum alloy; The target material is sputtered by bombarding the target with the working gas. In the step of forming a target film layer on the substrate, the nickel-platinum alloy is sputtered by bombarding the target with the working gas to form a metal silicide layer on the substrate.
9. The sputtering method according to claim 8, wherein: In the step of providing the substrate, the substrate includes a substrate, a gate structure located on the substrate, and source and drain doped layers located in the substrate on both sides of the gate structure; The nickel-platinum alloy is sputtered by bombarding it with the working gas. In the step of forming a metal silicide layer on the substrate, the metal silicide layer is formed on the top surface of the gate structure and the top surface of the source-drain doping layer.
10. The sputtering method according to claim 8, wherein The method further comprises: annealing the metal silicide layer after the working gas is used to bombard the nickel-platinum alloy for sputtering to form a metal silicide layer on the substrate.