Systems and methods for forming a metal hard mask in device fabrication

Abstract

The present disclosure relates to a method and system for substrate manufacturing. The method includes performing a first plasma enhanced surface treatment in a chamber prior to disposing a substrate, and then, subsequently, depositing a conditioning material in the process chamber. After depositing a plurality of conditioning materials in the process chamber, the substrate is disposed in the chamber. The substrate is positioned in the process chamber in contact with the conditioning material. Substrate processing is performed. The substrate processing may include one or more of the following: performing a second plasma enhanced surface treatment, forming a barrier layer on the substrate, or performing a low frequency RF treatment prior to forming a metal-based hard mask film on the substrate. The metal-based hard mask film includes one or more metals.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the fabrication of integrated circuits (ICs) for both memory and logic applications in semiconductor technology. The fabrication of these ICs may include lithography and transfer processes for transferring the fabricated patterns onto a substrate. The transfer process may employ a mask film. Background Art

[0002] Semiconductor devices include film stacks in which high aspect ratio features are formed. High aspect ratio features may be formed during various operations. A hard mask film may be used to form some high aspect ratio features to form features in the film stack during the processing of advanced logic and memory components. The hard mask film may include various metal materials, non-metal materials, or combinations of materials, depending on the type of device being fabricated. The hard mask film is designed to withstand long etching processes without degradation. Additionally, the hard mask exhibits higher mechanical strength and lower stress compared to other mask materials. However, conventional hard masks encounter delamination problems during processing. Delamination of the hard mask may negatively impact device fabrication, including etching and downstream operations.

[0003] Therefore, improved hard masks and hard mask formation methods are needed. Summary of the Invention

[0004] The present disclosure generally relates to systems and methods for fabricating devices using a metal-based hard mask, including the configuration and preparation of systems for fabricating these devices. In one example, a method of forming a hard mask includes: performing a first plasma-enhanced surface treatment in a process chamber; after performing the first plasma-enhanced surface treatment, depositing an aging material on a plurality of exposed surfaces of the process chamber. Additionally, in this example, after depositing the aging material on the plurality of exposed surfaces of the process chamber, a substrate is positioned in the process chamber, where the substrate is in contact with the aging material. At least one process is performed on the substrate, and the at least one process includes: performing a second plasma-enhanced surface treatment; forming a barrier layer on the substrate; or performing a low-frequency RF treatment. After performing the at least one process, a metal hard mask film is formed on the substrate.

[0005] In another example, a method of substrate fabrication includes: cleaning a process chamber; and subsequently, performing a first plasma-enhanced surface treatment in the process chamber. After performing the first plasma-enhanced surface treatment, an aging material is deposited on a plurality of exposed surfaces of the process chamber, the aging material including at least two or a combination of two or more of silicon oxide, silicon nitride, amorphous silicon, or a combination of the foregoing; positioning a substrate in the process chamber in contact with the aging material; and forming a metal hard mask film on the substrate.

[0006] In one example, a device includes: a silicon substrate; a plurality of alternating SiN-SiO 2 layers, the plurality of alternating SiN-SiO 2 layers being arranged to form a stack on the silicon substrate; a barrier layer formed on the stack; and a hard mask layer formed on the barrier layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To enable a detailed understanding of the manner in which the above-recited features of the present disclosure can be obtained, a more particular description of the disclosure briefly summarized above may be had by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of the scope of the disclosure, as the disclosure may admit to other equally effective embodiments.

[0008] Figure 1 is a flowchart of a substrate manufacturing method according to an embodiment of the present disclosure.

[0009] Figure 2 is a partial cross-sectional view of a process chamber in which a barrier layer and a metal-based hard mask film have been formed according to an embodiment of the present disclosure.

[0010] Figures 3A to 3B is a partial schematic view of a showerhead according to an embodiment of the present disclosure.

[0011] Figures 4A to 4B is a comparison of two defect scan images of the front side of a substrate fabricated with a tungsten hard mask film as discussed herein.

[0012] For ease of understanding, wherever possible, the same reference numerals have been used to denote the same elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. DETAILED DESCRIPTION

[0013] To enable devices to achieve higher capacity and lower unit cost, integrated circuit (IC) manufacturers are developing semiconductor technologies to reduce the critical dimension (CD) size during processing in logic and memory device applications. A non-collapse highly etch-selective hard mask as discussed herein is used to transfer a pattern to an underlying substrate by lithography to produce devices having increasingly smaller critical dimensions.

[0014] Embodiments of the systems and methods of the present disclosure relate to forming (depositing) defect-free metal-based hard masks on a variety of substrate types and geometries. In one embodiment, "defect-free" may mean that a predetermined number ("X") of defect additives (e.g., particulate contamination) of a predetermined diameter are permitted to be present in or on a semiconductor film of a predetermined thickness. In one example, for a semiconductor film of about thick on a 200 mm or 300 mm diameter substrate, there may be fewer than 10 defect additives greater than 32 nm. In another example, for thick film, there may be fewer than 30 defect additives greater than 90 nm.

[0015] The substrates on which the metal-based hard mask films are formed as discussed herein may include device substrates positioned in a process chamber for operations including film formation and patterning. The substrates on which the metal-based hard mask films (or hard mask materials) are formed as discussed herein may further include process chamber surfaces and components, including showerheads, baffle plates, and other components included in the process chamber.

[0016] Currently employed films for hard masks can have various challenges, including substrate adhesion, absence or inefficiency of a barrier layer, and undesired in-film defects including backside defects. Conventional metal-containing hard mask films used in logic applications and memory applications (which may be thicker films than those used in logic applications) exhibit poor (e.g., unusable or undesired) adhesion on substrates (substrates including silicon oxide, silicon nitride, polysilicon, amorphous silicon, etc.). Poor adhesion may be the result of fluorine (F) radicals (which are generated from WF 6 ), WF 6 being a commonly used tungsten precursor) diffusing through the hard mask film towards the hard mask-substrate interface. Once the F radicals at the hard mask-substrate interface are saturated, the saturated interface causes the hard mask film to delaminate from the underlying substrate and thus results in poor adhesion.

[0017] Unlike conventional applications, the hard mask films as discussed herein are used in combination with a barrier layer. The barrier layer may also be referred to herein as an initial layer and is formed on the substrate prior to hard mask deposition to prevent the diffusion of fluorine. The barrier layer further promotes the sufficient adhesion of the metal hard mask film (including tungsten hard mask film) on the desired substrate. In one example, the hard mask films as discussed herein may be formed as a single layer. In another example, the hard mask films as discussed herein may be formed as two or more layers. In one example, the hard mask film may be formed on the device substrate and / or on the process chamber components in a series of sub-operations.

[0018] In addition, the barrier layer discussed herein serves as a seed layer to provide sufficient nucleation sites for subsequent deposition of a bulk amorphous metal-based hard mask ("metal hard mask") film. The barrier layer promotes both uniform composition and morphology of the metal-based hard mask film (such as a tungsten hard mask film) along (through) the depth of the hard mask film. The barrier layer discussed herein exhibits etching behavior similar to that of the bulk tungsten hard mask film. The similar etching behavior prevents problems such as profile broadening during etching and hard mask residual material left after etching. The similar etching behavior can also mitigate other challenges posed by a material barrier layer that behaves less similarly to the bulk metal hard mask films employed in various embodiments of the present disclosure.

[0019] A plasma-enhanced deposition method and an improved gas flow distribution scheme can be used to deposit the metal-based hard mask discussed herein. Using the systems and methods discussed herein, metal-based hard mask films with a wide range of dopant concentrations (e.g., 10% to 80%) are formed. The hard mask films discussed herein can include one or more metals such as tungsten (W), cobalt (Co), titanium (Ti), molybdenum (Mo), yttrium (Y), zirconium (Zr), or other metals, or combinations and alloys of metals. The metal-based hard mask films can be formed to include dopants such as boron, carbon, nitrogen, and silicon and deposited on substrates (e.g., oxides, nitrides, amorphous silicon, oxide-nitride stacks, titanium nitride, silicon, polysilicon, etc.).

[0020] The metal-based hard mask films fabricated according to embodiments of the present disclosure exhibit viable adhesion and have no or substantially no defects on both the front and back sides of the substrate. In various examples, the dopant content can be from 10 wt% to 80 wt% of the total weight of the metal hard mask film. In some embodiments, the substrate on which the metal hard mask film is formed includes a silicon-based stack, e.g., can be in the range of 32 to 256 layers of alternating silicon oxide (SiO x ) and silicon nitride (SiN x ) layers. The stack is fabricated to be patterned by a method including etching. Masks (including the metal-based hard masks discussed herein) can be used to form these patterns. Thus, the metal-based hard masks discussed herein are formed to withstand etching of thicker stacks (e.g., 96 layers or more of silicon oxide / silicon nitride layers) than conventional masks. The metal-based hard masks discussed herein have a reduced likelihood and severity of delamination from the stack surface. Delamination of the hard mask can result in substrate defects, undercuts during etching, and / or poor or inconsistent etch selectivity among and between the layers of the stack.

[0021] Returning to the reference barrier layer, for next-generation node applications, the barrier layer is selected to exhibit thermal and mechanical properties and stoichiometry similar to those of a bulk hard mask material (e.g., tungsten hard mask). The similarity in properties and stoichiometry can prevent profile broadening during subsequent etching processes and can prevent unexpected hard mask residues, which improves device yield. Similarly, due to the in-film defect (inclusion) performance of the viable film, the films formed according to embodiments of the present disclosure can be used for future-generation applications. The in-film defect performance of the hard mask films discussed herein contributes to preventing misaligned profiles during hard mask opening etch operations, thereby mitigating subsequent etch profile misalignment and improving device yield.

[0022] During substrate processing, materials used to form a metal hard mask film (such as a tungsten hard mask film) can accumulate on the top electrode surface ("showerhead surface") in the process chamber. During plasma processing operations in the processing chamber, poor adhesion of the deposited metal hard mask film causes the metal hard mask film to flake or peel off from the top electrode. Conventional metal hard mask films can flake or peel onto the substrate or can manifest as in-film particle defects within the layers on the processed substrate, which can impede etching or other subsequent processes performed on the substrate. Using the systems and methods discussed herein, various methods can be employed singly or in combination to form a metal-based hard mask film. Silicon substrates with stacks greater than 96 layers can be successfully etched while mitigating delamination flaking of the metal-based hard mask material.

[0023] These systems and methods discussed herein can include operations such as: (1) cleaning the chamber before positioning the substrate in the chamber using a baffle designed to distribute gas more uniformly; (2) performing a plasma-enhanced chamber surface treatment using, for example, ionized / free radicalized nitrogen oxides (e.g., N 2 O) and ionized / free radicalized oxygen and / or helium before positioning the substrate in the chamber; (3) performing a plasma-enhanced conditioning material deposition, such as a silicon-rich material, in the chamber before positioning the substrate in the chamber; (4) performing a hydrogen and / or nitrogen plasma-enhanced surface treatment after positioning the substrate in the chamber; (5) independently of (4) or after (4), while the substrate is in the chamber, forming a barrier layer, such as a tungsten nitride barrier layer, by performing a cycle of immersing the substrate in a precursor and then performing a plasma-enhanced surface treatment, which plasma-enhanced surface treatment can include or exclude a process gas ramp, as opposed to maintaining the gas flow rate at a constant rate in the chamber during plasma processing after precursor immersion; and / or (6) applying a low-frequency RF while the substrate is in the chamber and using a process gas ramp. Although one example is described above, other examples are envisioned. For example, operation (3) can be performed before operation (2). In one embodiment, one or more gases employed at (1) can include argon, NF 3 or oxygen.

[0024] Using the systems and methods discussed herein, at least one layer of aged material (nozzle surface conditioning) can be used in combination with a barrier layer. A barrier layer that can also be used as a seed layer on the nozzle can provide an anchoring position for the deposited metal hard mask material. Additionally, the barrier layer prevents / suppresses the diffusion of fluorine towards the nozzle surface, which would otherwise cause the tungsten hard mask and / or the aged material to flake off (delaminate). In some embodiments, during the conditioning of the chamber and thus the nozzle before positioning the substrate in the chamber, at least silicon oxide and silicon nitride are employed in various predetermined ratios in order to contribute to the protection of chamber components. To form silicon oxide and / or silicon nitride, silicon, oxygen, and nitrogen precursors are utilized. RF power is used to ionize and / or radicalize the precursors to enhance the adhesion of the silicon oxide and silicon nitride to the nozzle to address the AlF x formation. The ratio of the percentage of silicon oxide:silicon nitride employed can include 100:0; 90:10; 80:20; 70:30; 60:40; 50:50, or other ranges of ratios up to 10:90 and including 10:90.

[0025] Another challenge in metal hard mask fabrication and use is the generation of backside defects that can be caused by aluminum contamination. For example, during a plasma / NF s3 cleaning process, an aluminum-containing substrate support or heater surface is partially converted to AlF x . In some examples, the AlF x will transfer to the backside of the substrate and thus cause undesirable aluminum contamination on the backside of the substrate. Additionally, the formed AlF x sublimes and deposits on the cold chamber inner surface (such as the nozzle surface).

[0026] Contrary to conventional methods, the aged material layer is deposited on the heater surface immediately after the plasma / NF 3 cleaning process is completed. Aluminum diffusion from the heater surface to the backside of the substrate is blocked by the aged layer to eliminate or mitigate aluminum backside contamination on the substrate. The aged layer can also inhibit the sublimation of AlF x onto the nozzle surface, which would otherwise cause poor adhesion of subsequent layers on the nozzle. Additionally, due to the relative softness of the silicon oxide layer and the silicon nitride layer, the use of silicon oxide and silicon nitride reduces scratching on the backside of the substrate.

[0027] Accordingly, using the systems and methods herein, the adhesion of a hard mask film (which can be a tungsten hard mask film) can be improved via the following operations: (1) surface treatment, (2) aged material deposition, and (3) barrier layer / seed layer deposition. In one example, the surface treatment applied to the nozzle removes AlF xResidues are used to enhance the adhesion of the aged material. The surface treatment further improves the nucleation of the metal hard mask film on the barrier layer / seeding layer. The aged material exhibits low hardness, good adhesion to the showerhead surface (to enable further processing), and provides anchoring sites for the deposition of the metal hard mask film on the showerhead and other surfaces with a barrier layer. The "low" desired hardness of the aged material discussed herein can be defined herein as less than 50% of the hardness of the substrate so as not to scratch the hardness of the substrate. In another example, the hardness of the aged material is less than 33% of the hardness of the substrate, or less than 25% of the hardness of the substrate. Turning to the barrier layer, in one example, the barrier layer includes the properties and stoichiometry of a bulk metal hard mask material, including similar behavior during an etching process.

[0028] Figure 1 is a flowchart of a substrate manufacturing method 100 according to an embodiment of the present disclosure. In some examples, at operation 102, for example, one or more gases (including chlorine) are used to clean the process chamber. In one example, operation 102 is performed before depositing one substrate or a batch of substrates into the process chamber. After the chamber cleaning at operation 102, at operation 104, a first plasma surface treatment is performed in the process chamber. The treatment at operation 104 may include a mixture of nitrogen oxides (e.g., N 2 O) and / or oxygen and helium. A high-frequency RF current (e.g., about 13.56 MHz) may be applied to ionize or radicalize the mixture of nitrogen oxides and / or oxygen and helium to form a high-frequency plasma. In other embodiments, at operation 104, one or more gases, such as nitrogen oxides, nitrogen (e.g., N 2 ), oxygen (e.g., O 2 ), helium, ammonia (NH 3 ), diborane (B 2 H 6 ), or propylene (C 3 H 6 ), may be used alone or in various combinations with one or more of the gases discussed above to generate a high-frequency RF plasma.

[0029] During the first plasma treatment at operation 104, the AlF x residues on the surface of the showerhead in the process chamber are converted to aluminum oxide (AlO x)。At operation 106, after the first plasma treatment at operation 104 and in the absence of one or more substrates in the process chamber, one or more conditioning material layers are deposited on the exposed surfaces inside the process chamber. The one or more conditioning material layers deposited at operation 106 may include silicon oxide, silicon nitride, amorphous silicon (a-Si), one or more alternating layers of silicon oxide and silicon nitride, one or more alternating layers of silicon oxide and amorphous silicon, one or more alternating layers of silicon nitride and amorphous silicon, etc. The exposed surfaces may include the showerhead surface, the substrate support surface, the chamber bottom, and / or the chamber sidewalls. Converting AlF x residue into aluminum oxide increases the adhesion of the subsequently deposited conditioning material to the process chamber surfaces and the showerhead. The conditioning layer deposited at operation 106 adheres to the showerhead to provide anchoring sites for subsequent hard mask material deposition at operation 112 discussed below. When fluorine is subsequently introduced into the process chamber and the showerhead is exposed to fluorine, the conditioning layer provided at operation 106 (which may be less than 60 angstroms and in some examples less than 30 angstroms or about 20 angstroms or less) prevents fluorine radicals from diffusing to the showerhead. As discussed above, fluorine radical diffusion causes fluorine to react with the aluminum showerhead, forming AlF x , which causes delamination or flaking of material from the showerhead, which may result in defects on the front-side surface of the substrate.

[0030] The conditioning materials discussed herein are soft in terms of hardness. In one example, the conditioning materials discussed herein have a hardness less than 50% of the hardness of the substrate. In another example, the conditioning materials discussed herein have a hardness less than 1 / 3 of the hardness of the substrate. When a substrate is placed in contact with the conditioning material, the hardness of the conditioning material relative to the hardness of the substrate contributes to reducing backside scratching of the substrate. When a higher hardness material is used (e.g., a material closer to the hardness of the substrate compared to the conditioning materials used at operation 106 discussed herein), backside scratching may occur during subsequent lithography processes. The conditioning material deposited at operation 106 may further be used to inhibit the diffusion of AlF x from the substrate support surface to the backside of the substrate, which otherwise would cause aluminum contamination of the substrate. At operation 108, one substrate or a batch of substrates is positioned in the process chamber, and one or more processing operations, such as deposition, etching, annealing, lithography, etc., may occur prior to the pre-hard mask treatment at substrate processing operation 110.

[0031] At substrate processing operation 110, one or more substrate processing sub-operations may be performed to form a barrier layer. As discussed herein, the formation of the barrier layer facilitates and promotes the formation of a metal hard mask film at operation 118 (discussed below). Due to the improved adhesion of the hard mask film to the substrate via the barrier layer, the hard mask films discussed herein are able to withstand etching and further processing. In one embodiment, at a first sub-operation 112 of substrate processing operation 110, an initial hydrogen and nitrogen plasma-enhanced surface treatment is applied to the aged layer. One or more sub-operations that may be performed at substrate processing operation 110 may optionally be performed individually or in combination, as discussed below. In some examples, one or more sub-operations at substrate processing operation 110 are performed sequentially.

[0032] During the hydrogen and nitrogen surface treatment at the first sub-operation 112 of substrate processing operation 110, hydrogen (H) bombardment generates surface Si-H bonds. The Si-H bonds serve as nucleation sites on the barrier layer for subsequent barrier layer deposition (at sub-operations 114A and 114B) and / or the hard mask layer at operation 118 (discussed below). Metal precursors (such as WF 6 ) interact with the nucleation sites to facilitate film formation. When 110 is performed in a cyclic process such that hydrogen and nitrogen treatment occurs on a tungsten-containing layer, hydrogen bombardment (after sub-operations 114A and 114B) further generates nitrogen vacancies in the treated film, thereby trapping fluorine radicals during metal hard mask deposition or subsequent barrier layer deposition. In examples where the metal hard mask and / or barrier layer includes tungsten, when the tungsten layer is converted to a tungsten nitride layer, hydrogen bombardment further increases the hydride content of the tungsten layer. The tungsten nitride layer serves as a barrier layer for the tungsten hard mask film or other metal-based hard mask films discussed herein to improve adhesion and nucleation.

[0033] In another embodiment that may be combined with other examples and embodiments herein, at a second sub-operation 114A of substrate processing operation 110, a precursor (such as WF 6 ) is introduced and adsorbed in a (quasi) monolayer on the substrate surface. Subsequently, a plasma-enhanced hydrogen and nitrogen surface treatment may be performed at a third sub-operation 114B of substrate processing operation 110. The third sub-operation 114B exposes the substrate to hydrogen and nitrogen plasma and reduces WF 6 to tungsten (W). Additionally, at the third sub-operation 114B, the tungsten layer is converted to tungsten nitride. In one example that may be combined with other examples herein, the first sub-operation 112 may be combined with the second sub-operation 114A and the third sub-operation 114B.

[0034] In substrate processing operation 110, the use of an initial hydrogen and nitrogen surface treatment in the first sub-operation 112 eliminates the use of conventional boron (B) or silicon (Si) precursors for forming a tungsten layer on the substrate. The use of boron- or silicon-containing precursors in a conventional process may cause problems regarding process flow / device fabrication due to boron or silicon contamination of materials disposed on the substrate.

[0035] The thickness of a tungsten nitride (WN) layer formed during substrate processing operation 110 can be controlled by adjusting the number of process cycles. A single cycle of the second sub-operation 114A and the third sub-operation 114B can be iteratively repeated multiple times during substrate processing operation 110 until a barrier layer having a thickness within a predetermined thickness range is formed. In one embodiment, in order to form a metal-based barrier layer using tungsten at the second sub-operation 114A and the third sub-operation 114B, a plurality of nucleation sites are formed on the substrate for tungsten nucleation. In a conventional process, a boron or silicon precursor can adsorb on the substrate surface and then chemically react with tungsten to nucleate tungsten on the substrate. However, this can result in boron or silicon residues from unreacted precursors. The formation of boron or silicon residues may impede the formation of a hard mask film and may inhibit downstream operations. By using H 2 / N 2 treatment in the first sub-operation 112 at substrate processing operation 110, surface dangling bonds are formed that serve as tungsten nucleation sites. In this example, the use of boron or silicon precursors is eliminated.

[0036] In one example, a cycle of the second sub-operation 114A and the third sub-operation 114B can form a barrier layer that is approximately to thick. Compared to a bulk deposition method that may aim to deposit a thicker film layer (such as 20 angstroms to 40 angstroms or greater), the thickness control of the barrier layer via a cyclic operation improves the tunability of the barrier layer properties. In substrate processing operation 110, the cyclic deposition process utilized at the second sub-operation 114A and the third sub-operation 114B can be used alone or in combination with the first sub-operation 112. In another example, at substrate processing operation 110, the cyclic deposition process utilized at the second sub-operation 114A and the third sub-operation 114B can be used alone or in combination with the fourth sub-operation 116. In this example, the cyclic deposition process does not rely on plasma distribution. Instead, one or more parameters of the soak at the second sub-operation 114A at substrate processing operation 110, such as duration, precursor type, and precursor concentration, enable angstrom-level control of barrier layer formation. The tunability and control of barrier layer formation enable consistency in the formation of a cover layer (such as a hard mask as discussed herein) across the entire substrate, regardless of the plasma distribution in the process chamber.

[0037] In another example, a barrier layer formed by one or more cycles of a second sub-operation 114A and a third sub-operation 114B can be formed to be about to about in thickness. In other examples, a barrier layer formed by one or more cycles of a second sub-operation 114A and a third sub-operation 114B can be formed to be about to about in thickness. In still other examples, a barrier layer formed by one or more cycles of a second sub-operation 114A and a third sub-operation 114B can have a target thickness. In some embodiments, one or more cycles of a second sub-operation 114A and a third sub-operation 114B are performed in a high-frequency (RF) environment at about 13.56 MHz or greater.

[0038] In some embodiments, a gas ramp can be employed at one or more of the second sub-operation 114A and the third sub-operation 114B at the substrate processing operation 110. A gas ramp is defined herein as adjusting the flow or one or more precursor gases entering the process chamber such that the gas flow rate varies within a predetermined gas flow rate range. Depending on the embodiment, during one or more of the second sub-operation 114A and the third sub-operation 114B at the substrate processing operation 110, the gas flow can ramp up (increase the gas flow) and / or ramp down (decrease the gas flow). Compared to an instant gas flow conventionally employed, the gas ramp discussed herein can be configured for a target gas flow rate that may take from 5 seconds to 30 seconds to achieve. During an instant gas flow, the gas flow initiation during processing results in reaching the target flow rate or range upon initiation of the gas flow. Compared to conventional methods, this relatively slow ramp according to embodiments herein can facilitate and enable an increased and thus sufficient time for the barrier layer to nucleate. In one example, the gas ramp can increase the flow rate of WF 6 from 0 sccm to 85 sccm in 5 seconds using a 17 sccm / s ramp rate. In some embodiments, the gas ramp is implemented in conjunction with a prior plasma-enhanced hydrogen-nitrogen surface treatment at the first sub-operation 112 of the substrate processing operation 110. In this example, the barrier layer formed during the substrate processing operation 110 enables the hard mask to adhere sufficiently to different substrates, which would otherwise result in reduced adhesion in the absence of the barrier layer. The barrier layer deposited during the ramp operation exhibits the same composition and / or properties as the hard mask film subsequently formed therein. The similarity in behavior between the barrier layer and the bulk hard mask film prevents or reduces the severity of problems such as profile broadening after an etching process, or the presence of hard mask residues, or other challenges in hard mask formation as discussed herein.

[0039] Optionally, a fourth sub - operation 116 can be utilized. During the fourth sub - operation 116 of the substrate processing operation 110, when there is a plasma formed by nitrogen and / or hydrogen in the process chamber, low - frequency RF processing can be employed. The low - frequency RF processing can be performed at a frequency below 13.56 MHz (e.g., at 2 MHz, 350 KHz, or other frequencies suitable for various embodiments). This can correspond to applying a bias to the substrate support between 200 W and 300 W, as compared to high - frequency RF processing that can occur at above about 600 W. The low - frequency RF processing at the fourth sub - operation 116 of the substrate processing operation 110 can be employed in combination with or independently of the first sub - operation 112. In another example that can be combined with other examples herein, the fourth sub - operation 116 can be completed in addition to the second sub - operation 114A and the third sub - operation 114B at the substrate processing operation 110.

[0040] At operation 118, a metal hard - mask film is formed on the barrier layer. The metal hard - mask film is formed to a thickness, for example, from about 0.2 microns to about 2.0 microns. In one example, the metal hard - mask film formed at operation 118 has a dopant concentration from about 10% to about 80%. One or more dopants included in the metal hard - mask film can include, such as boron, carbon, nitrogen, or silicon. The hard - mask film that can be formed at operation 118 includes one or more metals, such as tungsten (W), cobalt (Co), titanium (Ti), molybdenum (Mo), yttrium (Y), zirconium (Zr), or other metals, or combinations and alloys of metals.

[0041] As discussed herein, a system for manufacturing a film stack and a metal - based hard - mask film can be configured to be in various operating states to perform operations and sub - operations via a controller. The controller transmits programming information to various elements in the system, such as heater elements, pressure elements, gas - flow elements, and / or substrate - processing elements.

[0042] Figure 2 is a cross - sectional view of a process chamber 200 in which a barrier layer and a metal - based hard - mask film have been formed according to an embodiment of the present disclosure. The process chamber 200 includes a showerhead 202 that is disposed parallel to the substrate support assembly 214 and is separated from the substrate support by a distance 216. In one embodiment, the substrate support assembly 214 can include a heater and / or other components, some of which are discussed below. The substrate support assembly 214 contacts a first AlF x residual layer 204A. The showerhead 202 contacts a second AlF x residual layer 204B. The aging layers discussed herein can be formed as a first aging layer 206A on the first AlF x residual layer 204A and a second aging layer 206B on the second AlF x residual layer 204B.

[0043] The substrate 210 is positioned on the first aging layer 206A and is in direct contact with the first aging layer. The first barrier layer 208A is formed on the first side 218 of the substrate 210. The second barrier layer 208B is formed on the second aging layer 206B. The first metal hard mask film 212A is formed on the first barrier layer 208A. The metal hard mask material 212B will also be formed on the second barrier layer 208B. Although Figure 2 various layer thicknesses are shown, this is for illustrative purposes and not to limit the description of the thickness or relative thickness of the components shown.

[0044] Although Figure 2 one embodiment is shown, other embodiments are also contemplated. For example, in other embodiments, the substrate 210 may include an additional barrier layer (not shown) formed on the bottom (back) surface 220 of the substrate 210 opposite the first side 218 of the substrate 210. The additional barrier layer on the back surface 220 of the substrate 210 may be formed in a manner similar to that for forming the barrier layer at the substrate processing operation 110 as discussed in the substrate manufacturing method 100. The additional barrier layer protects the back surface 220 from AlF x contamination.

[0045] Figure 3A and Figure 3B are partial schematic views of a nozzle according to an embodiment of the present disclosure. In the example of Figure 3A the nozzle 202 includes a baffle plate 304 and a panel 306. Figure 3A It further includes a centerline 330 that is disposed centrally through the baffle plate 304 and the panel 306.

[0046] A plurality of baffle plate holes 308 are formed in the baffle plate 304. A plurality of panel holes 322 are formed in the panel 306. In one example, the baffle plate 304 is coupled to the panel 306, where the gap therebetween defines an air chamber. In this example, the position of each of the plurality of panel holes 322 corresponds to the position of each of the plurality of baffle plate holes 308 (e.g., is axially aligned therewith). Alternatively, some or all of the baffle plate holes 308 are offset from the panel holes 322. In other examples, little or no gap may be formed between the baffle plate 304 and the panel 306. In some examples that may be combined with other examples herein (not shown here), the position of each of the plurality of baffle plate holes 308 does not correspond to the position of each of the plurality of panel holes 322. The plurality of baffle plate holes 308 may be spaced apart from each other at a plurality of different distances. Figure 3A The first spacing 310, the second spacing 312, and the third spacing 314 are shown. Although Figure 3AThe plurality of baffle holes 308 are shown perpendicular to axis 318 and parallel to axis 316, but in alternative embodiments, some or all of the plurality of baffle holes 308 may be at an angle other than 90 degrees relative to axis 318. In one example, some or all of the plurality of baffle holes 308 may be angled toward or away from centerline 302.

[0047] In one embodiment, the plurality of baffle holes 308 have a first pitch 310 of the holes measured from a first edge 320A of the baffle 304. For reference, a second edge 320B opposite the first edge 320A is also shown. Various features shown on a first side of the centerline 302 (e.g., the side closest to the first edge 320A) are mirror images across the centerline 302. In one example, the first pitch 310 between adjacent holes in the plurality of baffle holes 308 is less than a second pitch 312 between adjacent baffle holes in the plurality of baffle holes 308. In another example that may be combined with other examples herein, the second pitch 312 between adjacent baffle holes in the plurality of baffle holes 308 may be less than a third pitch 314 between adjacent baffle holes 308. In this example, the relative pitch of the plurality of baffle holes 308 may increase toward the centerline 302 of the baffle 304. The plurality of baffle holes 308 may be configured in various ways in different designs of the baffle to evenly distribute gas (indicated by the dashed arrows) in the process chamber 300. This design is contrary to, for example, a baffle having a uniformly spaced hole distribution. A uniformly spaced hole distribution may cause gas to be received in a central region of the process chamber 300 (e.g., at a position coaxial with the centerline 302 in the process chamber). Thus, a uniformly spaced hole distribution does not evenly distribute gas in the process chamber 300.

[0048] Although Figure 3AMultiple baffle holes 308 in [the baffle] are shown as having approximately similar diameters, but it is contemplated that the diameter of each of the multiple baffle holes 308 can vary in the baffle. In one example, the baffle 304 includes a "hole gradient". In a baffle having a hole gradient, the diameters of the multiple baffle holes 308 that are closer to the edges 320A and 320B of the baffle 304 are greater than the diameters of the multiple baffle holes 308 that are positioned closer to the centerline 302 of the baffle 304. In some examples, the hole gradient of the baffle can be configured such that, in some examples, there is a higher concentration of baffle holes per surface area of the multiple baffle holes 308 toward the edges 320A and 320B of the baffle 304 rather than toward the centerline 302. The hole gradient of the baffle 304 can be configured to have a higher concentration of holes per surface area of the baffle holes 308 toward the edges 320A and 320B of the baffle 304. This higher concentration is in comparison to the baffle holes 308 among the multiple baffle holes 308 that are closer to the centerline 302. The hole gradient of the tunable baffle 304 can be adjusted to achieve and facilitate improved gas flow, including improved gas flow distribution toward the edges 320A / 320B of the panel 306.

[0049] Using the systems and methods discussed herein, the total gas conductivity is increased and the gas distribution of the gas and plasma in the process chamber is modified, thereby improving uniformity to reduce the total cleaning time. The increased gas conductivity can inhibit the formation of AlF x . Thus, the increased gas conductivity improves the adhesion of the aging layer on the showerhead and reduces defects in the film. The distribution of the process gas (especially at the centerline 302) can be adjusted via the configuration of the baffle 304 compared to the distribution of the process gas at the first edge 320A and the second edge 320B. The control of the uniform distribution of the process gas enables the control of the hard mask film uniformity and the adhesion behavior of the hard mask film.

[0050] Figures 4A to 4B is a defect scan image of the front side of a substrate fabricated with a tungsten hard mask film as discussed herein. Figure 4A shows at Figure 1 the first defect scan image of a substrate 410A fabricated without using plasma and aging processes at operations 104 and 106. Figure 4A The substrate of [the previous description] shows more than 200 defects in the film on the back side of the substrate. In contrast, Figure 4B shows a second defect scan image of a substrate 410B fabricated according to an embodiment of the present disclosure. Figure 4B The substrate shown in [the previous description] is fabricated using hydrogen and nitrogen plasma treatments and an aging process, which can be similar to the processes discussed at operations 104 and 106 in Figure 1 [the previous description]. Figure 4B The substrate in [the previous description] shows only 4 defects.

[0051] Thus, using the systems and methods herein, the adhesion of the metal hard mask film is improved, resulting in longer lifetimes of process chamber components and reduced incidence and severity of substrate defects. A hard mask film fabricated on a surface without a barrier layer between the hard mask film and the substrate has poor adhesion, increasing the likelihood of delamination. In contrast, a metal hard mask film formed on a barrier layer according to embodiments of the present disclosure exhibits improved adhesion. Thus, the metal hard mask film formed on the barrier layer does not exhibit peeling or delamination, or exhibits a reduced likelihood and / or severity of peeling or delamination. The metal hard mask films discussed herein can be formed not only on process chamber components, but also on substrates used in semiconductor device components.

[0052] The surface treatment applied to the showerhead removes AlF x residue, which enhances the adhesion of the aged material to the showerhead and improves the adhesion of subsequent deposited layers, including the hard mask film and / or materials. The aged material can adhere well to the showerhead surface, reducing the likelihood of substrate defects due to flaking. The aged material also provides anchor points for depositing the metal hard mask film on the showerhead and other surfaces of the process chamber on which a barrier layer is disposed. When a barrier layer is employed, one or more materials selected for the barrier layer can have material properties, such as etch selectivity and / or stoichiometry, that are substantially similar to one or more metals included in the metal hard mask. Selecting materials with similar material properties and / or stoichiometry improves the adhesion of the metal hard mask film to the barrier layer.

[0053] Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments can be envisioned without departing from the basic scope of the present disclosure, and the scope of the embodiments is determined by the appended claims.

Claims

1. A method of forming a hard mask, comprising: performing a first plasma-enhanced surface treatment in a process chamber; after performing the first plasma-enhanced surface treatment, depositing an aging material on a plurality of exposed surfaces of the process chamber; after depositing the aging material on the plurality of exposed surfaces of the process chamber, positioning a substrate in the process chamber and bringing it into contact with the aging material; performing a treatment on the substrate to form a barrier layer on the substrate, the treatment comprising: performing a second plasma-enhanced surface treatment, wherein the second plasma-enhanced surface treatment is a hydrogen and nitrogen plasma-enhanced surface treatment; after performing the second plasma-enhanced surface treatment, adsorbing a precursor on the surface of the substrate; after adsorbing the precursor, performing a third plasma-enhanced surface treatment, the third plasma-enhanced surface treatment being a plasma-enhanced hydrogen and nitrogen surface treatment; and performing a low-frequency RF treatment; and after performing the treatment on the substrate, forming a metal hard mask film on the substrate.

2. The method according to claim 1, wherein, the aging material comprises at least two of silicon oxide, silicon nitride, amorphous silicon, or a combination of the above items.

3. The method according to claim 1, wherein, the aging material has a hardness less than half of the hardness of the substrate.

4. The method according to claim 1, wherein, the first plasma-enhanced surface treatment includes introducing a gas into the process chamber through a baffle plate, the baffle plate includes holes, and the holes have unequal spacings therebetween.

5. The method according to claim 1, wherein forming the barrier layer includes at least one cycle of: soaking the substrate in a precursor for a first time period to form a target barrier layer thickness, and subsequently, performing a plasma-enhanced treatment for a second time period.

6. The method according to claim 5, wherein, the target barrier layer thickness is from 3 angstroms to 50 angstroms.

7. The method according to claim 5, wherein, during the second time period, ramping up a plurality of gases used in the plasma-enhanced treatment to a target gas flow rate within a predetermined gas flow time period.

8. The method according to claim 7, wherein, the predetermined gas flow time period is from 5 seconds to 30 seconds.

9. A method of substrate manufacturing, comprising: cleaning the process chamber; subsequently, performing a first plasma-enhanced surface treatment in the process chamber; after performing the first plasma-enhanced surface treatment, depositing an aging material on a plurality of exposed surfaces of the process chamber, the aging material comprising at least two or a combination of silicon oxide, silicon nitride, amorphous silicon, or a combination of the above items; positioning a substrate in the process chamber to be in contact with the aging material; performing a treatment on the substrate to form a barrier layer on the substrate, the treatment comprising: performing a second plasma-enhanced surface treatment, wherein the second plasma-enhanced surface treatment is a hydrogen and nitrogen plasma-enhanced surface treatment; After performing the second plasma-enhanced surface treatment, a precursor is adsorbed on the surface of the substrate; After the precursor is adsorbed, a third plasma-enhanced surface treatment is performed, and the third plasma-enhanced surface treatment is a plasma-enhanced hydrogen and nitrogen surface treatment; and A low-frequency RF treatment is performed; and A metal hard mask film is formed on the substrate.

10. The method according to claim 9, wherein, the metal hard mask film includes a first metal, and the first metal includes at least one of tungsten (W), cobalt (Co), titanium (Ti), molybdenum (Mo), yttrium (Y), zirconium (Zr), or an alloy or combination of the foregoing items.

11. The method according to claim 10, wherein, the metal hard mask film further includes a dopant, and the dopant includes at least one of boron, carbon, nitrogen, or silicon.

12. The method according to claim 9, wherein, the first metal includes tungsten (W), cobalt (Co), titanium (Ti), molybdenum (Mo), yttrium (Y), or zirconium (Zr), and the barrier layer includes the first metal.

13. The method according to claim 9, further comprising: During the formation of the barrier layer, introducing a plurality of process gases into the process chamber; and Performing a gas ramp during the formation of the barrier layer.

14. The method according to claim 13, wherein, During the gas ramp, a target gas flow of the plurality of process gases is achieved in the process chamber within a time period of 5 seconds to 30 seconds after the plurality of process gases are introduced into the process chamber.

15. A device, comprising: A silicon substrate; A stack including a plurality of alternating silicon nitride layers and silicon oxide layers formed on the silicon substrate; A barrier layer formed on the stack by: Performing a hydrogen and nitrogen plasma-enhanced surface treatment on the stack; Adsorbing a precursor on the surface of the substrate; After the precursor is adsorbed, performing a plasma-enhanced hydrogen and nitrogen surface treatment; and A metal hard mask film formed on the barrier layer.

16. The device according to claim 15, wherein, the metal hard mask film includes a first metal, and the first metal includes at least one of tungsten (W), cobalt (Co), titanium (Ti), molybdenum (Mo), yttrium (Y), zirconium (Zr), or an alloy or combination of the foregoing items.

17. The device according to claim 16, wherein, the metal hard mask film further includes a dopant, and the dopant includes at least one of boron, carbon, nitrogen, or silicon.

18. The device according to claim 16, wherein, the barrier layer has a thickness in the range of 5 angstroms to 30 angstroms.

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