Method of forming a structure including a metal hard mask

Abstract

Methods of forming and using structures including a metal hard mask layer are disclosed. The metal hard mask can include desirable properties, such as relatively high tensile strength, even after subsequent etching steps. Exemplary methods include depositing a metal hard mask layer using a cyclic deposition process. The metal hard mask layer can include one or more of, for example, a metal nitride, a metal carbide, and a metal carbonitride.

Description

Technical Field

[0001] This disclosure generally relates to methods suitable for forming electronic devices. More specifically, this disclosure generally relates to methods for forming structures including hard masks. Background Technology

[0002] In the manufacturing process of electronic devices, fine feature patterns can be formed on the substrate surface by patterning the substrate surface and removing material from the substrate surface using processes such as wet etching and / or dry etching. Photoresist is commonly used for this patterning of the substrate surface.

[0003] Photoresist patterns can be formed by: coating a photoresist layer onto a substrate surface, masking the surface of the photoresist, exposing the unmasked portion of the photoresist to radiation, such as ultraviolet light or an electron beam, and removing a portion of the photoresist (e.g., the unmasked or masked portion), while leaving a portion of the photoresist (e.g., another of the unmasked or masked portions) on the substrate surface. Once the photoresist is patterned, the patterned photoresist can be used as a template to etch material on the substrate surface in the area where the photoresist has been removed, to form a transfer pattern in the layer beneath the photoresist. After etching, any remaining photoresist can be removed.

[0004] In some cases, hard masks may be necessary to facilitate pattern transfer to the underlying layer on the substrate. For features with relatively high aspect ratios, feature patterning using hard masks may be particularly desirable. Using hard masks can mitigate the exposure of the material layer on the substrate to the plasma process used to remove the photoresist, thereby reducing defects in features formed by photolithography. The use of hard masks can also provide the desired etch selectivity between the hard mask and the underlying layer to be etched.

[0005] During the formation of patterned features, the use of some hard mask materials can lead to undesirable line twisting and / or line edge roughness. Therefore, there is a need for improved methods to form structures that include hard masks.

[0006] Any discussion set forth in this section (including discussions of problems and solutions) is included in this disclosure for the purpose of providing background information and should not be construed as an admission that any or all of the discussions were known at the time of making this invention or otherwise constitute prior art. Summary of the Invention

[0007] This invention provides a simplified overview of some concepts, which will be described in further detail below. This invention is not intended to require the identification of key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0008] Various embodiments of this disclosure relate to methods for forming structures including a metallic hard mask layer. The metallic hard mask layer can be used to transfer patterns to one or more underlying layers. As described in more detail below, exemplary hard masks described herein can be used to form features or patterns having a relatively high aspect ratio (e.g., an aspect ratio greater than 20:1) and relatively small line twist and / or relatively low line edge roughness.

[0009] According to embodiments of this disclosure, a method for forming a structure including a metal hard mask is provided. The method includes providing a substrate in a reactor and forming a metal hard mask layer on the substrate. The step of forming the metal hard mask may include repeating a cycle comprising: supplying a metal-containing precursor to the substrate, supplying reactants to the substrate, and applying power to the reactor to activate the reactants, thereby reacting them with the metal-containing precursor or a derivative thereof on the substrate to form the metal hard mask. The hard mask may be or include one or more of metal nitrides, metal carbides, and metal carbonitrides. Examples of these embodiments include one or more of molybdenum and tungsten. Alternatively or additionally, the metal-containing precursor comprises a compound having one or more =NR groups, wherein each R is independently selected from C2-C6 straight-chain or branched alkanes. Alternatively or additionally, the metal-containing precursor may be or include a compound having one or more -NRx groups, wherein each R is independently selected from C1-C4 straight-chain or branched alkanes, and wherein x is 1 to 3. In some cases, the method includes providing two or more metal-containing precursors to the substrate. The reactants may be or include one or more of argon, hydrogen, and / or nitrogen. Various parameters, such as temperature, pressure, plasma power, time, etc., can be adjusted according to aspects of these embodiments to obtain the desired tensile stress of the deposited hard mask layer. Depositing a hard mask layer with the desired tensile stress can mitigate line twisting and / or line edge roughness that could otherwise occur after a subsequent etching process.

[0010] According to another embodiment of this disclosure, a method for forming a layer stack on a substrate is provided. An exemplary method includes providing a substrate in a reactor, forming an etch stop layer on the substrate, forming a low-k layer on the etch stop layer, forming an oxide capping layer on the low-k layer, forming a metal hard mask layer on the oxide capping layer, and forming a mask layer. In examples of these embodiments, the metal hard mask layer includes one or more of metal nitrides, metal carbides, and metal carbonitrides. The method may further include etching a portion of the layer stack to form recesses therein and filling the recesses with a conductive material, such as copper.

[0011] For the purpose of summarizing the invention and its advantages relative to the prior art, certain objects and advantages of the invention may have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the invention. Therefore, for example, those skilled in the art will recognize that the invention may be embodied or implemented in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0012] All these embodiments are intended to fall within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings. The invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0013] Embodiments of this disclosure can be more fully understood when considered in conjunction with the following illustrative drawings, and by referring to the detailed description and claims.

[0014] Figure 1 A method for forming a structure according to one or more embodiments of the present disclosure is shown.

[0015] Figure 2 Timings according to one or more embodiments of this disclosure are shown.

[0016] Figure 3 Structures according to one or more embodiments of this disclosure are shown.

[0017] Figure 4 Another method according to one or more embodiments of this disclosure is shown.

[0018] Figures 5 to 9 Structures according to one or more embodiments of this disclosure are shown.

[0019] Figure 10 Transmission electron microscope images of a hard mask layer according to one or more embodiments of the present disclosure are shown.

[0020] Figure 11 The deposition state and the thickness of the hard mask layer after etching are shown according to one or more embodiments of the present disclosure.

[0021] Figure 12 The deposition state and post-etching hard mask layer stress according to one or more embodiments of the present disclosure are shown.

[0022] It should be understood that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be exaggerated relative to other elements to aid in understanding the embodiments shown in this disclosure. Detailed Implementation

[0023] The following description of exemplary embodiments of the methods is merely illustrative and for purposes of explanation only. The following description is not intended to limit the scope of this disclosure or the claims. Furthermore, the description of multiple embodiments having indicated features or steps is not intended to exclude other embodiments having additional features or steps, or other embodiments including different combinations of said features or steps.

[0024] In this disclosure, the gas may include materials that are gaseous at ambient temperature and pressure (NTP), evaporated solids, and / or evaporated liquids, and may consist of a single gas or a mixture of gases, depending on the circumstances. Gases other than process gases, i.e., gases introduced without passing through gas distribution components, other gas distribution devices, etc., may be used, for example, to seal the reaction space, and may include a sealing gas. Precursors and reactants may be gases. Exemplary sealing gases include rare gases, nitrogen, etc. In some cases, the term precursor may refer to a compound that participates in a chemical reaction to produce another compound, particularly a compound constituting the membrane matrix or the membrane backbone; the term reactant may be used interchangeably with the term precursor.

[0025] As used herein, the term substrate can refer to any one or more underlying materials that can be used to form or on which devices, circuits, or films can be formed according to the methods of embodiments of this disclosure. A substrate may comprise a bulk material (such as silicon (e.g., single-crystal silicon)), other group IV materials (e.g., germanium), or other semiconductor materials (e.g., group II-VI or III-V semiconductor materials) and may comprise one or more layers overlying or underlying the bulk material. Furthermore, the substrate may include various features formed within or on at least a portion of the substrate layers, such as recesses, protrusions, etc. By way of example, the substrate may comprise a bulk semiconductor material and an insulating or dielectric material layer covering at least a portion of the bulk semiconductor material. The substrate may be continuous or discontinuous; rigid or flexible; solid or porous. The substrate may be of any form, such as a plate or workpiece. Plate-type substrates may include wafers of various shapes and sizes. A continuous substrate may extend beyond the boundary of the processing chamber where the deposition process takes place and may move through the processing chamber such that the process continues until the end of the substrate is reached. Continuous substrates may be supplied from a continuous substrate supply system that allows the manufacture and output of continuous substrates in any suitable form. Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, fiber webs, flexible materials, or bundles of continuous filaments or fibers (i.e., ceramic fibers or polymer fibers). Continuous substrates may also include carriers or sheets on which non-continuous substrates are mounted.

[0026] As used herein, the terms film and / or layer can refer to any continuous or discontinuous structure and material, such as materials deposited by the methods disclosed herein. For example, films and / or layers can include two-dimensional materials, three-dimensional materials, nanoparticles, partially or entirely molecular layers, or partially or entirely atomic layers or atomic and / or molecular clusters. A film or layer can include a plurality of dispersed atoms on a substrate surface or can be at least partially composed of such atoms and / or can be embedded in or transformed into being embedded in a substrate and / or can be embedded in or transformed into being embedded in a device fabricated on the substrate. A film or layer can include a material or layer having pinholes and / or isolation islands. A film or layer can be at least partially continuous. A film or layer can be patterned, e.g., subdivided, and can be included in multiple semiconductor devices. A film or layer can be selectively grown on some portions of a substrate and not on others.

[0027] The term cyclic deposition process or cyclic deposition process can refer to the sequential introduction of precursors (and / or reactants) and / or plasma power into a reaction chamber to deposit a layer on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), hybrid cyclic deposition processes including ALD and cyclic CVD components, and plasma-enhanced ALD, CVD, and hybrid cyclic processes. In some cases, one or more reactants and / or precursors are continuously supplied to the reaction chamber, and the plasma power may be pulsed.

[0028] The term atomic layer deposition can refer to a vapor phase deposition process in which deposition cycles, typically multiple consecutive cycles, are performed in a processing chamber. As used herein, the term atomic layer deposition is also intended to include processes specified by related terms such as chemical vapor deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas-source MBE, organometallic MBE, and chemical beam epitaxy when performed using alternating pulses of precursor / reactive gases and purge gases (e.g., inert carrier gases). Pulsing may include exposing the substrate to a precursor or reactant. This can be accomplished, for example, by introducing the precursor or reactant into a reaction chamber in which the substrate is present. Alternatively or concurrently, exposing the substrate to a precursor may include moving the substrate to a location in the substrate processing system where the reactant or precursor is present.

[0029] As used herein, a structure may be or include a substrate as described herein. A structure may include one or more layers covering or within a substrate, such as one or more layers formed according to the methods described herein. All or part of the device may be included within or on the structure.

[0030] Numerous exemplary materials are provided throughout the embodiments of this disclosure. It should be noted that the chemical formulas given for each example material should not be construed as limiting, and the non-limiting example materials given should not be limited by the given example stoichiometry.

[0031] In this disclosure, any two numbers of a variable may constitute a feasible range of the variable, and any range indicated may include or exclude endpoints. Furthermore, any value of the indicated variable (whether or not it is indicated by “about”) may refer to an exact value or an approximate value and include equivalents, and in some embodiments may refer to an average, median, representative value, multi-value, etc. Additionally, in this disclosure, the terms “comprising,” “consisting of,” and “having,” as well as related words, may independently mean “generally or broadly comprising,” “including,” “substantially composed of,” or “consisting of” in some embodiments. The meaning of any definition in this disclosure does not necessarily exclude the common and customary meanings in some embodiments. In some cases, percentages indicated herein may be relative or absolute percentages. The term “about” may represent + / - 20%, 10%, 5%, 2%, 1%, or 0.5% of the stated size, orientation, shape, value, etc.

[0032] In this specification, it will be understood that the terms "on" or "above" may be used to describe relative positional relationships. Another element, film, or layer may be directly on the mentioned layer, or another layer (intermediate layer) or element may be inserted between them, or a layer may be disposed on the mentioned layer but not completely cover the surface of the mentioned layer. Similarly, it will be understood that the terms "below," "under," or "beneath" will be interpreted as relative concepts.

[0033] Switch to the attached image. Figure 1 An exemplary method 100 for forming a structure including a metal hard mask layer is illustrated. In short, method 100 includes providing a substrate in a reactor (step 102) and forming a metal hard mask layer on the substrate (step 104). Method 100 is applicable to a variety of applications, particularly during the fabrication of electronic devices. For example, method 100 can be used for back-end process (BEOL) processing of electronic devices. Alternatively or additionally, the exemplary method described herein can be used to etch high aspect ratio features with good reliability and relatively low defects. The hard mask material described herein can also be etched away relatively easily (the vapor pressure can be less than that of TiN) while mitigating damage to the underlying layers. This allows for relatively smooth pattern transfer.

[0034] During step 102, a substrate is provided in the reaction chamber. As described above, the substrate can have various forms and can include bulk material and one or more layers and / or features formed within and / or overlying the bulk material. The reaction chamber used during step 102 can be or includes the reaction chamber of a vapor deposition reactor system configured to perform a cyclic deposition process. The reaction chamber can be a standalone reaction chamber or part of a cluster of tools.

[0035] Step 102 may include heating the substrate to a desired deposition temperature within the reaction chamber. In some embodiments of this disclosure, step 102 includes heating the substrate to a temperature below 500°C. For example, in some embodiments of this disclosure, heating the substrate to the deposition temperature may include heating the substrate to temperatures between about 20°C and about 500°C, below 475°C, below 450°C, between about 150°C and 450°C, between about 150°C and 425°C, or between about 175°C and 400°C, or between about 300°C and 350°C. In some cases, the temperature is controlled at a relatively high temperature (e.g., greater than 310°C) such that the deposition of the metal hard mask during step 104 results in the deposition of a material with relatively high (e.g., greater than 0.16 GPa or 2.1 GPa) tensile stress. The relatively high temperature (e.g., greater than 310°C) is believed to facilitate the volatilization and removal of byproducts during the formation of the metal hard mask layer.

[0036] In addition to controlling the temperature of the substrate, the pressure inside the reaction chamber can also be adjusted. For example, in some embodiments of this disclosure, the pressure inside the reaction chamber during step 102 and / or at the start of step 104 may be less than 1500 Pa or between about 200 and about 1000 Pa, or between about 250 and about 750 Pa.

[0037] During step 104, a metal hard mask layer is formed on the substrate. According to an example of this disclosure, step 104 is a cyclic deposition process comprising repeating a cycle including: supplying a metal-containing precursor to the substrate, supplying a reactant to the substrate, and applying power to the reactor to activate the reactant, thereby reacting with the metal-containing precursor or its derivative on the substrate to form a metal hard mask. According to an example of this disclosure, the metal hard mask layer is or includes one or more of metal nitrides, metal carbides, and metal carbonitrides. As discussed in more detail below, various properties of the metal hard mask layer (e.g., to obtain relatively high tensile strength and / or low crystallinity) can be tuned to mitigate line twisting and / or line edge roughness in features that might otherwise occur—particularly in structures including line pitches of 28 nm or less. Other properties that can be tuned include etch rate and etch selectivity relative to the underlying layer.

[0038] Figure 2 An exemplary sequence 200 or cycle suitable for use with step 104 is shown. In the example shown, sequence 200 includes the steps of providing one or more reactants (step 202), providing one or more precursors (step 204), and applying power to the reactor (step 206). As shown, this cycle can be repeated (step 208).

[0039] During step 202, one or more reactants are provided to the reaction space within the reactor. The reactants may be or include, for example, an inert gas, a hydrogen-containing gas, and / or a nitrogen-containing gas. The inert gas may be or include, for example, one or more of argon and helium. The nitrogen-containing gas may include one or more of nitrogen (N2), NH3, or N2H2. The hydrogen-containing gas may include one or more of hydrogen (H2), H2O, or H2O2. Reactants containing hydrogen and nitrogen may include mixtures of hydrogen and nitrogen, ammonia, hydrazine, alkyl-substituted hydrazine, etc. In some cases, the reactants may include argon and a hydrogen-containing gas (e.g., hydrogen) to form a metal carbide. In some cases, the reactants may include hydrogen and nitrogen (e.g., nitrogen-containing and / or hydrogen-containing gases) to form a metal nitride. In some cases, the reactants contain hydrogen, nitrogen, and an inert gas (e.g., nitrogen-containing and / or hydrogen-containing gases and argon) to form a metal carbonitride. In some cases, the flow rate ratio of hydrogen-containing gas (e.g., hydrogen), nitrogen-containing gas (e.g., nitrogen), and inert gas (e.g., argon) is approximately 1:1:2. In some cases, the inclusion of nitrogen as a reactant is considered to improve the properties of the deposited metallic hard mask material.

[0040] During step 202, the flow rate of one or more reactants (e.g., each) can be between about 100 sccm and about 6000 sccm. The duration of step 202 can be sustained through one or more cycles.

[0041] During step 204, a metal precursor is supplied (e.g., pulsed) to the reaction space within the reactor. According to various embodiments of this disclosure, the precursor comprises one or more of molybdenum and tungsten. In other words, the metal-containing precursor comprises one or more of a molybdenum precursor and a tungsten precursor. In some cases, the metal-containing precursor comprises both a molybdenum-containing precursor and a tungsten-containing precursor. In these cases, the molybdenum-containing precursor and the tungsten-containing precursor may be supplied simultaneously or alternately and sequentially to the reaction space / substrate. The flow rate ratio of the molybdenum precursor to the tungsten precursor may be about 1:10 or about 1:1.

[0042] According to various examples of this disclosure, the metal-containing precursor is or comprises a compound having one or more =NR groups, wherein each R is independently selected from C2-C6 straight-chain or branched alkanes. According to another example, the metal-containing precursor is or comprises a compound having one or more -NRx groups, wherein each R is independently selected from C1-C4 straight-chain or branched alkanes, and wherein x is 1 to 3. As a specific example, the metal-containing precursor may be or comprises one or more of the following: bis(tert-butylimino)bis(dimethylamino)molybdenum[( tBuN)2(NMe2)2Mo], bis(tert-butylimino)bis(dimethylamino)tungsten[((CH3)3CN)2W(N(CH3)2)2] or dicarbonyl[(1,2,3,4,5-η)-1-methyl-2,4-cyclopentadien-1-yl]nitrosylmolybdenum[CH3C5H4Mo(CO)2NO].

[0043] The flow rate of the precursor to the reaction space can be between approximately 10 sccm and approximately 1000 sccm. The duration of step / pulse 204 can be between approximately 0.1 seconds and approximately 30 seconds.

[0044] During step 206, power is applied to the reactor to activate the reactants, thereby reacting them with the metal-containing precursor or its derivative on the substrate to form a metal hard mask. The power can be applied to, for example, a gas distribution device, such as a spray head assembly. In some cases, opposing electrodes (e.g., a base) are grounded. The power applied during step 206 can have an intensity between about 200 W and about 800 W, or between about 100 W and about 1000 W. The duration of step 206 can be between 4 seconds or between about 0.1 seconds and about 30 seconds, to obtain, for example, the desired tensile stress in the deposited metal hard mask material.

[0045] The reactor can be purged with reactants and / or one or more inert gases after steps 204 and / or 206. A vacuum source can also be used to facilitate purging.

[0046] Figure 3 A structure 300 that can be formed using method 100 is illustrated. In the illustrated example, structure 300 includes a substrate 302 and a metal hard mask layer 304. The metal hard mask layer 304 is deposited on the substrate 302 using method 100. The metal hard mask layer 304 can be or includes one or more of, for example, molybdenum nitride (MoN), molybdenum carbide (MoC), molybdenum carbonitride (MoCN), tungsten nitride (WN), tungsten carbide (WC), tungsten carbonitride (WCN), and molybdenum carbonitride (WMoCN).

[0047] According to various aspects of these embodiments, the tensile stress of the metal hard mask layer is greater than 2.1 GPa, between about 200 MPa and about 2000 MPa, or between about 100 MPa and about 2500 MPa. Alternatively, the profile roughness (Rq) of the metal hard mask layer is about 0.3 nm or less—for example, between about 0.1 and about 0.3 nm. Alternatively, the dielectric constant of the metal hard mask layer is about 3.0 or less.

[0048] When the metal hard mask layer 304 comprises a metal nitride (such as MoN or WN), it was observed that adding nitrogen to the plasma gas during deposition increased the nitrogen concentration in the metal hard mask layer, altered the carbon concentration in the metal hard mask layer, and decreased the oxygen concentration in the metal hard mask layer. Table 1 below shows exemplary process conditions and the corresponding tensile stresses in the metal hard mask layer 304.

[0049] Table 1

[0050]

[0051] The metal hard mask layer 304 may include organic carbon. The organic carbon in the film may correspond to byproducts or unreacted precursor molecules, while carbon in the form of MoC represents a direct bond between carbon and Mo.

[0052] The organic C% in the metal hard mask layer 304 can be reduced or can be reduced by three important factors: (i) high temperature, (ii) longer RF on-time, and (iii) an appropriate ratio of H2:N2:Ar during the process. Exemplary process conditions are provided above.

[0053] As described above, byproducts and unreacted precursors are volatilized and removed at high temperatures, longer RF on-times support more chemical reactions, N2 plasma in the deposition cycle improves the conversion of precursors to metal nitride films (e.g., MoN), and hydrogen-containing gas (e.g., H2) and inert gas (e.g., Ar) plasmas support the removal of byproducts and any unreacted reactants.

[0054] In some cases, the organic carbon in the metal hard mask layer 304 corresponds to the -CH, C=O, OC=O bonds in the film. That is, the methyl and butyl groups in the precursor can react with oxygen on the wafer (natural oxides or some impurities on the wafer surface) in the presence of H2 plasma, and the precursor molecules can also remain in the film in an unreacted form.

[0055] The reason why organic carbon drives compressive stress is the reduction / contraction of the intermolecular space of organic compounds or porous structures (at high temperature, low pressure, longer RF on-time and HRF power), which reduces their volume and compresses the membrane. As a result, the membrane exhibits relatively high compressive stress.

[0056] Figure 4Another method 400 according to an example of this disclosure is shown. Method 400 includes providing a substrate in a reactor (step 402), forming an etch stop layer on the substrate (step 404), forming a low-k layer on the etch stop layer (step 406), forming an oxide capping layer on the low-k layer (step 408), forming a metal hard mask layer on the capping layer (step 410), and forming a mask layer (step 412). As described above, the metal hard mask layer may be or include one or more of metal nitrides, metal carbides, and metal carbonitrides.

[0057] During step 402, a suitable substrate is provided. The substrate can be as described above. The reactor can also be as described above. The steps of method 400 can be suitably performed in one or more reactors, which can be part of a cluster of tools.

[0058] During step 404, an etch stop layer is formed on the substrate. The etch stop layer can be, or includes, for example, silicon nitride, SiN, etc. The etch stop layer can be formed using, for example, PECVD or ALD.

[0059] During step 406, a low-k layer is formed on the etch stop layer (e.g., directly). The low-k layer can be or includes, for example, SiOCH or SiOC. The low-k layer can be formed using, for example, PECVD or ALD.

[0060] During step 408, an oxide capping layer is formed on the low-k layer (e.g., directly). The oxide capping layer can be or includes, for example, silicon oxide. The oxide capping layer can be formed using, for example, PECVD or ALD.

[0061] During step 410, a metal hard mask layer is formed on the oxide overlay (e.g., directly). Step 410 can be the same as or similar to method 100 described above. The metal hard mask material can be combined as described above. Figure 3 As stated above.

[0062] During step 412, a mask layer is formed on the metal hard mask layer (e.g., directly). The mask layer can be applied using, for example, spin coating or vapor phase processes. The mask material can be or includes a photoresist material, such as an EUV photoresist material.

[0063] Figure 5 Structure 500 is shown, comprising a layer stack 502 on a substrate 504, the substrate 504 having an etch stop layer 506. The substrate 504 may be or include a substrate as described herein. The etch stop layer 506 may be as described above. The thickness of the etch stop layer may be between about 1 and about 5 nm.

[0064] Layer stack 502 includes a low-k layer 508, an oxide capping layer 510 on the low-k layer, and a metal hard mask layer 512 on the oxide capping layer. Structure 500 also includes a mask layer 514 covering the metal hard mask layer 512. The low-k layer 508, oxide capping layer 510, and metal hard mask layer 512 can be as described above. The thickness of the low-k layer 508 can be between about 100 and about 200 nm. The thickness of the oxide capping layer 510 can be between about 1 and about 5 nm. The thickness of the metal hard mask layer 512 can be between about 5 and about 20 nm.

[0065] Although not shown separately, method 400 may additionally include patterning a mask layer (e.g., through a mask and a development mask layer) and / or a portion of an etch layer stack (e.g., a low-k layer, an oxide overlay layer, and a portion of a metal hard mask layer) to form a recess. Etching may include multiple etching steps, such as plasma dry etching and CMP. The method may also include filling the recess with a conductive material (e.g., copper). The conductive material (e.g., copper) may be deposited using, for example, PVD.

[0066] Exemplary methods may also include etching a low-k layer beneath the hard metal mask layer. The low-k layer can be etched using, for example, argon / C4F8 / oxygen plasma. During low-k layer etching, the hard metal mask layer may become more compressible. To compensate for this, the hard metal mask layer ideally has a relatively high initial tensile stress, such as the tensile stress described herein.

[0067] Figure 6 The diagram shows a structure 600 following the patterned mask layer 514 and the hard metal mask layer 512 to form features 602, 604, and 606, including patterned mask materials 603, 605, and 607, and hard metal mask material features 608, 610, and 612. The hard metal mask layer 512 can be etched using, for example, Cl2 / argon plasma.

[0068] After etching the metal hard mask, mask layers 602, 604, and 606 can be removed, and metal hard mask features 608, 610, and 612 can be used to pattern the low-k layer 508 and oxide overlay layer 510 to form features 702, 704, and 706, such as... Figure 7 As shown. Features 702-706 include hard mask materials 608, 610, 612, oxide overlay materials 708, 710, 712, and low-k materials 714, 716, 718.

[0069] Figure 8Another structure 800 according to an example of this disclosure is shown. Structure 800 includes a substrate 802, an etch stop layer 804, a silicon oxide layer 806, a metal hard mask layer 808, and a patterned feature 810. The substrate 802 and the etch stop layer 804 may be the same as or similar to the substrate 504 and the etch stop layer 506 described above, respectively. The silicon oxide layer 806 may be formed using, for example, PECVD or ALD. The thickness of the silicon oxide layer 806 may be between about 1 and about 3 nm. The patterned feature 810 may be formed by exposing and developing a mask layer (e.g., the mask layer 514 described above).

[0070] Figure 9 Structure 900 is shown after patterning a metal hard mask layer 808 (e.g., as described above) and etching a silicon oxide layer 806, etching an etch stop layer 804, removing the patterned features 810 (e.g., using an ashing process), and etching a substrate 802 to form features 902, 904, 906, 908, 910, and 912. For example, argon / CF4 / CH4 can be used. x F y Oxygen plasma is used to etch the silicon oxide layer 806. For example, argon / CF4 / CH can be used. x F y Oxygen plasma is used to etch the etch stop layer 804. Features 902-912 include a substrate material 914 (e.g., silicon), an etch stop material 916 (e.g., silicon nitride), a silicon oxide material 918, and a metal hard mask material 920.

[0071] Figure 10 Transmission electron microscopy (TEM) images of the WMoCN metallic hard mask layer in its deposited state and after etching of the low-k material are shown. The microscopy images reveal some oxidation that occurred on the WMoCN surface after etching of the low-k material.

[0072] Figure 11 and Figure 12 An example is shown where the metal in the hard metal mask layer is tungsten (e.g., the layer is WN or WCN). Specifically, Figure 11 The figure shows the deposited thickness of the metal hard mask and the thickness of the metal hard mask layer after etching the low-k material under various conditions. As shown, the thickness of the metal hard mask material does not change significantly. Figure 12 The tensile stress in the hard metal mask layer after deposition and etching of low-k material is shown.

[0073] For the purpose of summarizing the invention and its advantages relative to the prior art, certain objects and advantages of the invention have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the invention. Therefore, for example, those skilled in the art will recognize that the invention may be embodied or implemented in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0074] All these embodiments are intended to fall within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings. The invention is not limited to any particular embodiment disclosed.

Claims

1. A method for forming a structure comprising a metal hard mask layer on a substrate, the method comprising: Provide a substrate in the reactor; and A hard metal mask layer is formed on a substrate by repeating the following cycle: Supply a metal-containing precursor to the substrate; Supplying reactants to the substrate; and Power is applied to the reactor to activate the reactants, thereby reacting them with metal-containing precursors or their derivatives on the substrate to form a metal hard mask. The metal hard mask layer comprises one or more of metal nitrides, metal carbides, and metal carbonitrides.

2. The method according to claim 1, wherein, The metal-containing precursor includes one or more of molybdenum and tungsten.

3. The method according to claim 1, wherein, The metal-containing precursor comprises a compound having one or more =NR groups, wherein each R is independently selected from C2-C6 straight-chain or branched alkanes.

4. The method according to claim 1, wherein, The metal-containing precursor comprises a compound having one or more -NRx groups, wherein each R is independently selected from C1-C4 straight-chain or branched alkanes, and wherein x is 1 to 3.

5. The method according to claim 2, wherein, The metal-containing precursor includes one or more of the following: bis(tert-butylimino)bis(dimethylamino)molybdenum[( t BuN)2(NMe2)2Mo], bis(tert-butylimino)bis(dimethylamino)tungsten[((CH3)3CN)2W(N(CH3)2)2] or dicarbonyl[(1,2,3,4,5-η)-1-methyl-2,4-cyclopentadien-1-yl]nitrosylmolybdenum[CH3C5H4Mo(CO)2NO].

6. The method according to claim 2, wherein, The metal-containing precursor includes the molybdenum-containing precursor and the tungsten-containing precursor, wherein the molybdenum-containing precursor and the tungsten-containing precursor are simultaneously supplied to the substrate.

7. The method according to claim 2, wherein, The metal-containing precursor includes the molybdenum-containing precursor and the tungsten-containing precursor, wherein the molybdenum-containing precursor and the tungsten-containing precursor are supplied to the substrate alternately and sequentially.

8. The method according to claim 1, wherein, The reactants include argon and hydrogen-containing gas to form the metal carbide.

9. The method according to claim 1, wherein, The reactants include hydrogen-containing gas and nitrogen-containing gas to form the metal nitride.

10. The method according to claim 1, wherein, The reactants include hydrogen-containing gas, nitrogen-containing gas, and argon gas to form the metal carbonitride.

11. The method according to claim 10, wherein, The flow rate ratio of the hydrogen-containing gas, the nitrogen-containing gas, and the argon gas is approximately 1:1:

2.

12. The method according to claim 1, wherein, The tensile stress of the metal hard mask layer is between approximately 200 MPa and approximately 2000 MPa.

13. The method according to claim 1, wherein, The profile roughness (Rq) of the metal hard mask layer is about 0.3 nm or less.

14. The method according to claim 1, wherein, The method is carried out at a temperature between approximately 150°C and approximately 450°C.

15. The method according to claim 1, wherein, The power is applied at an intensity between approximately 200W and approximately 800W.

16. The method according to claim 1, wherein, The method is carried out under pressures between approximately 200 Pa and approximately 1000 Pa.

17. The method according to claim 1, wherein, The dielectric constant of the metal hard mask layer is about 3.0 or less.

18. A method for forming a layer stack on a substrate, comprising: Provide a substrate in the reactor; An etch stop layer is formed on the substrate; A low-k layer is formed on the etch stop layer; An oxide capping layer is formed on the low-k layer; A hard metal mask layer is formed on the oxide capping layer; as well as Form a mask layer, The metal hard mask layer comprises one or more of metal nitrides, metal carbides, and metal carbonitrides.

19. The method of claim 18, further comprising etching a portion of the layer stack to form a recess therein, and then filling the recess with copper.

20. The method according to claim 18, wherein, The metal hard mask layer includes one or more of the following: molybdenum nitride (MoN), molybdenum carbide (MoC), molybdenum carbonitride (MoCN), tungsten nitride (WN), tungsten carbide (WC), tungsten carbonitride (WCN), and tungsten carbonitride molybdenum (WMoCN).

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