Method for depositing a film layer
By adjusting the inert gas flow rate, applying AC bias, and heating the substrate, the problem of asymmetric sidewall coverage in the substrate edge region during plasma deposition was solved, achieving higher deposition coverage and symmetry, and improving the accuracy of subsequent processes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- APPLIED MATERIALS INC
- Filing Date
- 2024-09-18
- Publication Date
- 2026-04-14
AI Technical Summary
In plasma deposition processes, the edge regions of the substrate exhibit asymmetrical sidewall coverage, leading to structural asymmetry and affecting the alignment accuracy of subsequent processes such as photolithography.
By adjusting the inert gas flow rate, applying an AC bias voltage to the substrate, and heating the substrate, the plasma distribution and ion flux density are controlled, thereby altering the trajectory and mobility of metal atoms to improve the sidewall coverage symmetry of the edge region.
It improves the symmetry of the structural sidewall coverage in the substrate edge region, thereby increasing the overall deposition coverage and the yield of subsequent processes.
Smart Images
Figure CN121866880A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of this principle generally relate to semiconductor processing of semiconductor substrates. Background Technology
[0002] During plasma deposition processes, the plasma may not be uniform, resulting in uneven sputtering of the target material onto the substrate. The inventors have observed that uneven plasma distribution leads to asymmetrical sidewall coverage in the edge regions of substrates with structures such as trenches and the like.
[0003] Therefore, the inventors have provided a method for improving structural coverage and also increasing the symmetrical sidewall coverage of the structure in the edge region of the substrate. Summary of the Invention
[0004] This paper provides a method for improving deposition coverage and reducing the asymmetric sidewall coverage of structures in the edge regions of a substrate.
[0005] In some embodiments, a method of depositing a film on a substrate may include: flowing an inert gas around the periphery of the substrate, wherein the flow rate of the inert gas is from about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of sidewall structures, and wherein the substrate has an edge region containing an edge structure adjacent to the periphery of the substrate; forming a plasma in a physical vapor deposition (PVD) process to ionize the inert gas to form an ion flux, thereby inducing the sputtering of a metal material to form metal atoms to deposit on the substrate, wherein the ionization percentage of the metal material is about three percent or less; generating an AC bias voltage on the substrate to increase the ion flux density at the edge region of the substrate, thereby altering the trajectory of metal atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias voltage is from about 100 watts to about 3000 watts; and heating the substrate to increase the mobility of the metal atoms deposited on the edge structure and increase the deposition coverage, wherein the temperature of the substrate is from about 150 degrees Celsius to about 500 degrees Celsius.
[0006] In some embodiments, the method may further include: depositing a metal material at a pressure of approximately 1.5 mTorr to approximately 14 mTorr, an AC bias of approximately 13.56 MHz, an inert gas of argon, and an ion flux of Ar+, a metallic material of aluminum or copper, at a temperature of approximately 300 degrees Celsius, with an AC bias of approximately 800 watts and an inert gas flow rate of approximately 50 sccm to approximately 325 sccm, a plurality of structures having openings less than approximately 0.3 micrometers in depth, a plurality of structures having openings approximately 0.8 micrometers in depth, a substrate having a plurality of chips (the chips containing a plurality of sidewall structures) on the surface of a substrate, wherein at least one of the plurality of sidewall structures is an alignment bond for a photolithography process, and / or tuning the sidewall coverage and diffusion properties of the metal material by adjusting the AC bias and temperature during deposition of the metal material on the substrate.
[0007] In some embodiments, a method of depositing a film on a substrate may include: flowing argon gas around the periphery of the substrate, wherein the flow rate of the argon gas is from about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of sidewall structures, and wherein the substrate has an edge region containing an edge structure adjacent to the periphery of the substrate; forming a plasma in a physical vapor deposition (PVD) process to ionize the argon gas to form an Ar+ ion flux, thereby inducing aluminum sputtering to generate aluminum atoms for deposition on the substrate; generating an AC bias voltage on the substrate to increase the ion flux density at the edge region of the substrate, thereby altering the trajectory of aluminum atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias voltage is from about 100 watts to about 3000 watts; and heating the substrate to increase the mobility of the aluminum atoms deposited on the edge structure and increase the deposition coverage, wherein the temperature of the substrate is from about 150 degrees Celsius to about 500 degrees Celsius.
[0008] In some embodiments, the method may further include: depositing aluminum on a substrate having a plurality of chips (each chip containing a plurality of sidewall structures) on the surface of a substrate at a pressure of about 1.5 mTorr to about 14 mTorr, an AC bias of about 13.56 MHz, a temperature of about 300 degrees Celsius, an AC bias of about 800 watts, and an argon flow rate of about 50 sccm to about 325 sccm, wherein at least one of the plurality of sidewall structures is an alignment bond for a photolithography process, and / or adjusting the sidewall coverage and diffusion properties of the aluminum by adjusting the AC bias and temperature during the deposition of the aluminum on the substrate.
[0009] In some embodiments, a non-transitory computer-readable medium is disclosed having instructions stored thereon that, when executed, cause a method of depositing a film layer on a substrate, the method comprising: flowing argon gas around the periphery of the substrate at a flow rate of about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of sidewall structures and wherein the substrate has an edge region containing edge structures adjacent to the periphery of the substrate; forming a plasma in a physical vapor deposition (PVD) process to ionize the argon gas to form an Ar+ ion flux, thereby inducing aluminum sputtering to generate aluminum atoms for deposition on the substrate; generating an AC bias voltage on the substrate to increase the Ar+ ion flux density at the edge region of the substrate, thereby altering the trajectory of aluminum atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias voltage is about 100 watts to about 3000 watts; and heating the substrate to increase the mobility of the aluminum atoms deposited on the edge structure and increase the deposition coverage, wherein the temperature of the substrate is about 150 degrees Celsius to about 500 degrees Celsius.
[0010] In some embodiments, a method for a non-transitory computer-readable medium may further include depositing aluminum at a pressure of about 1.5 mTorr to about 14 mTorr.
[0011] Other and further embodiments are disclosed below. Attached Figure Description
[0012] The embodiments of this principle, which are briefly summarized above and discussed in more detail below, can be understood by referring to the illustrative embodiments depicted in the accompanying drawings. However, the drawings only illustrate typical embodiments of this principle and should not be considered as limiting the scope, as other equally effective embodiments are permissible with respect to this principle.
[0013] Figure 1 A schematic cross-sectional view illustrating a physical vapor deposition (PVD) chamber according to some embodiments of this principle is shown.
[0014] Figure 2 These are methods for depositing films based on some embodiments of this principle.
[0015] Figure 3 Cross-sectional views of structures according to some embodiments of this principle and top views of substrates having multiple chips are depicted.
[0016] Figure 4 A cross-sectional view illustrating a PVD deposition process according to some embodiments of this principle is provided.
[0017] Figure 5Some embodiments based on this principle are illustrated, and a cross-sectional view of the PVD deposition process based on this principle is incorporated.
[0018] Figure 6 Cross-sectional views of deposited film layers on structures according to some embodiments of this principle are depicted.
[0019] Figure 7 A cross-sectional view is depicted on a structure of a substrate with AC bias and heated according to some embodiments of this principle, showing a deposited film layer.
[0020] Figure 8 A cross-sectional view depicting a deposited film layer on the bottom surface of a structure according to some embodiments of this principle is shown.
[0021] To facilitate understanding, the same reference numerals are used to denote common components in the figures where possible. The figures are not drawn to scale and may be simplified for clarity. Components and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation
[0022] The method provides an improved deposition process. By tuning the deposition process parameters, the deposition coverage and symmetry sidewall coverage are enhanced compared to conventional techniques. Precise control of the deposition trajectory guides the deposition to improve the sidewall coverage symmetry of structures such as trenches and the like near the edge regions of a substrate. The energy of the deposited adsorbed atoms is also increased to provide improved diffusion of adsorbed atoms during deposition, thereby increasing coverage and sidewall symmetry by allowing adsorbed atoms to move into the structure without forming seams.
[0023] In some manufacturing processes, a substrate may have numerous chips formed on its surface. These chips may contain structures with sidewalls, such as trenches and the like. During substrate processing, a deposition process can be used to deposit a material, such as a metallic material, over the substrate surface. If the chamber generates non-uniform plasma within its processing volume, deposited particles from the sputtering target may have different densities and trajectories, impacting the substrate surface near its edge regions at less-than-ideal angles. Conventional attempts to mitigate this problem include replacing the source magnet, redesigning the chamber, and similar approaches. However, these conventional attempts only slightly improve the sidewall and bottom coverage of the structure at the cost of reduced overall coverage. The method described in this paper essentially improves the symmetrical sidewall coverage of the structure while simultaneously increasing the overall deposition coverage.
[0024] The negative effects of asymmetric sidewall coverage in metal deposits such as aluminum and copper become apparent in various downstream processes. For example, coverage issues can occur during photolithography, ultimately reducing overall yield due to misalignment, etc. In some embodiments of this technique, an inert gas ion flux (such as, but not limited to, argon ions (Ar+)) is used to modify the sputtered atom trajectory to induce symmetric coverage on the sidewalls of the structure in the edge regions of the substrate. The inert gas ion flux is also used to increase the mobility of sputtered atoms after contact with the substrate surface, thereby increasing symmetric coverage and overall coverage. Controlled ion flux helps mitigate edge region sidewall asymmetry induced by non-uniform distribution of plasma and sputtered atom trajectories in the edge regions of the substrate. This technique introduces an AC bias on the substrate to influence the inert gas ion flux and the trajectory of sputtered atoms in the edge regions. The substrate temperature can also be increased to further increase the mobility of sputtered atoms on the substrate, thereby enhancing sidewall symmetry and overall deposition coverage.
[0025] In some embodiments, the method of this principle may be, for example, but not limited to, Figure 1 The process is performed in a physical vapor deposition (PVD) chamber 100. The walls 102 of the PVD chamber 100 enclose a process volume 140, in which film material can be deposited on a substrate 108. The substrate 108 is supported by a base 110, which includes bias electrodes 112 electrically connected to an AC bias power supply 114. An inert gas source 116 supplies inert gas into the process volume 140. During deposition, the inert gas 118 flows upward and around a periphery 124 of the substrate 108 and into the process volume 140. The substrate 108 has a surface 132 including a central region 128 and an edge region 120. A DC power supply 104 supplies power to a target 106 to generate plasma 122 in the process volume 140 during deposition. In some embodiments, the target may be a metallic material such as aluminum, copper, or the like. The target 106 deposits the metallic material as a film layer onto the substrate 108 during sputtering. The magnetron 126 rotates around the central axis 130 during deposition to enhance the sputtering of the target 106.
[0026] Figure 2 This is method 200, which involves depositing a film layer on a substrate. (Refer to...) Figure 1 and Figures 3 to 8 Let's discuss method 200. In block 202, substrate 108 has a structure with sidewalls in at least edge region 120 of substrate 108. In some embodiments, a plurality of chips 302 are formed on surface 132 of substrate 108, such as... Figure 3As depicted in view 300A. As described above, method 200 enhances deposition on the structural openings, particularly in the edge region 120 of the substrate 108. The plurality of chips 302 include a structure 304 having sidewalls 306 and a bottom 308, as shown in view 300A. Figure 3 As depicted in view 300B. In some embodiments, structure 304 may be a shallow (e.g., a depth 310 of about 0.3 micrometers or less) or deep trench (a depth 310 of about 0.8 micrometers or greater) and the like. In some embodiments, structure 304 may be an alignment bond for a photolithography process.
[0027] like Figure 4 As depicted in view 400, the plasma 122 has a non-uniform density during deposition onto the substrate 108. A denser plasma region is denoted as 122A, and a less dense plasma region is denoted as 122B. The varying plasma density is a result of the magnetic field generated by the magnetron 126. The outer portion 402 of the magnetron 126 generates magnetic field lines 406 with a higher density than the less dense magnetic field lines 408 of the inner portion 404. The denser plasma region 122A generates dense target particles 410 (e.g., metal atoms) to be deposited on the substrate 108, while the less dense plasma region 122B generates less dense target particles 412 to be deposited on the substrate 108. The central region 128 of the substrate 108 has the deposition of both dense target particles 410 and less dense target particles 412 from all directions. The structure 304A of the central region 128 has a symmetrical sidewall coverage within the structure 304A. The deposition in the edge region 120 of substrate 108 primarily originates from dense target particles 410 on the inner sidewall 414 and less dense target particles 412 on the outer sidewall 416, resulting in an asymmetric sidewall coverage by the deposited film 418. For downstream processes that utilize the minimum film depth as the center point 420 of structure 304, the asymmetry in sidewall coverage causes a shift 422 in the minimum film depth point, leading to alignment errors and similar errors.
[0028] In block 204, inert gas 118 flows around the perimeter 124 of substrate 108, such as... Figure 1 PVD chamber 100 and Figure 5 As depicted in view 500. In some embodiments, the inert gas may be argon or the like. In some embodiments, the flow rate of the inert gas may be from about 10 sccm to about 3000 sccm. In some embodiments, the flow rate may be from about 50 sccm to about 325 sccm. In some embodiments, the flow rate may be 70 sccm, 160 sccm, or 320 sccm. Figure 6As depicted in view 600A, the asymmetric sidewall coverage is primarily caused by the impact of dense target particles 410 on the inner sidewall 414. The flow rate of the inert gas can be adjusted to deflect a portion of the dense target particles 410, thereby preventing some of the dense target particles 410 from depositing on the inner sidewall 414, such as... Figure 6 As depicted in view 600B. The reduction of dense target particles 410 impacting the inner sidewall 414 contributes to achieving symmetrical sidewall coverage.
[0029] In block 206, plasma 122 is formed to ionize the inert gas to create an ion flux to sputter metal atoms for deposition on substrate 108. A portion of the ion flux will bombard target 106 and cause sputtering of target 106, in which metal atoms are released and travel toward substrate 108 as part of the deposition process. Another portion of the ion flux travels toward substrate 108 in a random manner. In some embodiments, the target is a metallic material with a low ionization percentage of less than approximately three percent. The low ionization percentage allows most of the ionized particles to originate from the inert gas rather than the metallic material. Highly ionized metallic materials would produce more metal particles that could interfere with the method of the present invention, as the high ionization could be too great to be offset by the inert gas ionization flux and other techniques discussed below.
[0030] In block 208, an AC bias voltage is generated on substrate 108 to precisely control the ion energy and ion flux density at the edge region 120 of substrate 108, such as... Figure 5 As depicted in the diagram. The AC bias results in a high-energy, high-density ion flux 502 in the edge region 120 and a low-density ion flux 504 in the central region 128. (As shown in the diagram...) Figure 7 As depicted in view 700A, the high-density ion flux 502 results in a reduction in the impact of dense target particles 410 on the inner sidewall 414 (less deposition), thereby increasing the symmetric sidewall coverage. The high-density ion flux 502 also promotes increased mobility 702 of metal atoms deposited on the surface 132 of the substrate 108, thereby promoting surface diffusion. In some embodiments, the AC bias may have a frequency of approximately 13.56 MHz. In some embodiments, the AC bias power may range from approximately 100 watts to approximately 3000 watts. In some embodiments, the AC bias power may be approximately 800 watts. The inventors have found that increasing the DC power supplied to the target has little effect on the sidewall asymmetric coverage.
[0031] In block 210, the substrate 108 is heated 704 to further increase the mobility 702 of metal atoms on the surface 132 of the substrate 108, thereby promoting surface diffusion, such as Figure 7As depicted in view 700B. In some embodiments, substrate 108 may be heated to from about 150 degrees Celsius to about 500 degrees Celsius. In some embodiments, substrate 108 may be heated to about 300 degrees Celsius. Higher temperatures result in higher mobility of metal atoms on surface 132, but the upper limit of the temperature is constrained by the melting point of the metal material. The thermal budget of structure 304 on substrate 108 may also further constrain the upper limit of the temperature range. Higher mobility of metal atoms allows atoms to have sufficient energy to diffuse into the existing material already deposited on surface 132. Increased mobility allows atoms to flow into structure 304 and increase symmetric sidewall coverage, rather than simply accumulating on the inner sidewall 414. In block 212, the process is performed at pressures from about 1.5 mTorr to about 14 mTorr. Adjusting the process pressure allows for further control of the inert gas flux and sidewall coverage.
[0032] In some embodiments, the AC bias can be used to tune the ion flux, while temperature can be used to promote surface diffusion. In some embodiments, the AC bias can be approximately 800 watts, the temperature can be approximately 300 degrees Celsius, and the flow rate of the inert gas (argon) can be approximately 50 sccm to approximately 325 sccm to deposit aluminum onto the substrate, thereby achieving symmetrical sidewall coverage in the edge regions. The method 200 described above can also be used for deep trench structures, where the objective is to uniformly deposit metallic material on the bottom 308 of the structure 304B, such as... Figure 8 As depicted in the diagram. Structure 304B in the edge region 120 will have deposited material 802 biased towards the inner sidewall 414, such as... Figure 8 As depicted in view 800A. By utilizing the method 200 described above, bottom deposition can be used to center the deposited material 802 on the bottom 308, as shown in view 800A. Figure 8 As depicted in view 800B.
[0033] Embodiments based on this principle can be implemented using hardware, firmware, software, or any combination thereof. Embodiments can also be implemented using instructions stored on one or more computer-readable media, which can be read and executed by one or more processors. Computer-readable media can include any means for storing or transmitting information in a machine-readable form (e.g., a computing platform or a “virtual machine” running on one or more computing platforms). For example, computer-readable media can include any suitable form of volatile or non-volatile memory. In some embodiments, computer-readable media can include non-transitory computer-readable media.
[0034] Although the foregoing are embodiments of this principle, other and further embodiments of this principle can be designed without departing from its basic scope.
Claims
1. A method for depositing a film layer on a substrate, comprising the following steps: An inert gas is allowed to flow around the periphery of the substrate, wherein the flow rate of the inert gas is from about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of structures with sidewalls, and wherein the substrate has an edge region containing an edge structure close to the periphery of the substrate. In a physical vapor deposition (PVD) process, a plasma is formed to ionize the inert gas to create an ion flux, thereby inducing the sputtering of metal material to form metal atoms to be deposited on the substrate, wherein the ionization percentage of the metal material is about three percent or less. An AC bias voltage is generated on the substrate to increase the ion flux density at the edge region of the substrate, thereby changing the trajectory of metal atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias voltage is from about 100 watts to about 3000 watts. as well as The substrate is heated to increase the mobility of the metal atoms deposited on the edge structure and to increase the deposition coverage, wherein the temperature of the substrate is from about 150 degrees Celsius to about 500 degrees Celsius.
2. The method according to claim 1, further comprising the following steps: The metallic material is deposited at pressures ranging from approximately 1.5 mTorr to approximately 14 mTorr.
3. The method of claim 1, wherein the frequency of the AC bias is approximately 13.56 MHz.
4. The method of claim 1, wherein the inert gas is argon and the ion flux is composed of Ar+.
5. The method according to claim 1, wherein the metallic material is aluminum or copper.
6. The method of claim 1, wherein the temperature is approximately 300 degrees Celsius, the AC bias is approximately 800 watts, and the flow rate of the inert gas is approximately 50 sccm to approximately 325 sccm.
7. The method of claim 1, wherein the plurality of structures have openings with a depth of less than about 0.3 micrometers.
8. The method of claim 1, wherein the plurality of structures have openings with a depth of approximately 0.8 micrometers.
9. The method of claim 1, wherein the substrate has a plurality of chips on the surface of the substrate, the plurality of chips having the plurality of sidewall structures.
10. The method of claim 1, wherein at least one of the plurality of sidewalled structures is an alignment key for a photolithography process.
11. The method of claim 1, further comprising the following steps: The sidewall coverage and diffusion properties of the metal material are tuned by adjusting the AC bias and temperature during deposition on the substrate.
12. A method for depositing a film layer on a substrate, comprising the following steps: Argon gas is flowed around the periphery of the substrate at a flow rate of about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of structures with sidewalls, and wherein the substrate has an edge region containing an edge structure close to the periphery of the substrate. In a physical vapor deposition (PVD) process, a plasma is formed to ionize the argon gas to form an Ar+ ion flux, thereby inducing aluminum sputtering to generate aluminum atoms for deposition on the substrate; An AC bias is generated on the substrate to increase the Ar+ ion flux density at the edge region of the substrate, thereby changing the trajectory of aluminum atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias is from about 100 watts to about 3000 watts. as well as The substrate is heated to increase the migration rate of the aluminum atoms deposited on the edge structure and to increase the deposition coverage, wherein the temperature of the substrate is from about 150 degrees Celsius to about 500 degrees Celsius.
13. The method of claim 12, further comprising the following steps: The aluminum is deposited at pressures ranging from approximately 1.5 mTorr to approximately 14 mTorr.
14. The method of claim 12, wherein the frequency of the AC bias is approximately 13.56 MHz.
15. The method of claim 12, wherein the temperature is approximately 300 degrees Celsius, the AC bias is approximately 800 watts, and the flow rate of the argon gas is approximately 50 sccm to approximately 325 sccm.
16. The method of claim 12, wherein the substrate has a plurality of chips on the surface of the substrate, the plurality of chips having the plurality of sidewall structures.
17. The method of claim 12, wherein at least one of the plurality of sidewalled structures is an alignment key for a photolithography process.
18. The method of claim 12, further comprising the following steps: The sidewall coverage and diffusion properties of the aluminum are tuned by adjusting the AC bias and temperature during the deposition of the aluminum on the substrate.
19. A non-transitory computer-readable medium having instructions stored thereon, the instructions, when executed, causing a method for depositing a film layer on a substrate, the method comprising the steps of: Argon gas is flowed around the periphery of the substrate at a flow rate of about 10 sccm to about 3000 sccm, wherein the surface of the substrate has a plurality of structures with sidewalls, and wherein the substrate has an edge region containing an edge structure close to the periphery of the substrate. In a physical vapor deposition (PVD) process, a plasma is formed to ionize the argon gas to form an Ar+ ion flux, thereby inducing aluminum sputtering to generate aluminum atoms for deposition on the substrate; An AC bias is generated on the substrate to increase the Ar+ ion flux density at the edge region of the substrate, thereby changing the trajectory of aluminum atoms impacting the edge region to increase the sidewall coverage symmetry of the edge structure, wherein the AC bias is from about 100 watts to about 3000 watts. as well as The substrate is heated to increase the migration rate of the aluminum atoms deposited on the edge structure and to increase the deposition coverage, wherein the temperature of the substrate is from about 150 degrees Celsius to about 500 degrees Celsius.
20. The non-transitory computer-readable medium of claim 19, the method further comprising the following steps: The aluminum is deposited at pressures ranging from approximately 1.5 mTorr to approximately 14 mTorr.