Methods of forming metal chalcogenide columns

Abstract

Methods of generating a self-aligned structure are described, the self-aligned structure including a metal chalcogenide. Certain methods include forming a metal-containing film in a substrate feature and exposing the metal-containing film to a chalcogenide precursor to form a self-aligned structure including a metal chalcogenide. Certain methods include forming a metal-containing film in a substrate feature; expanding the metal-containing film to form a cylinder; and exposing the pillar to a chalcogenide precursor to form a self-aligned structure comprising a metal chalcogenide. Certain methods include the step of directly forming a metal chalcogenide pillar in a substrate feature to form a self-aligned structure including a metal chalcogenide. Methods of forming self-aligned vias are also described.

Description

[0001] This application is a divisional application of an invention patent application with an application date of March 6, 2019, application number 201980014978.4, and name “Method for forming metal sulfide columns”. Technical Field

[0002] Embodiments of the present disclosure generally relate to methods of forming metal chalcogenide pillars extending from substrate features. Additional embodiments relate to methods of creating self-aligned vias. Background Art

[0003] Self-aligned metal oxide pillars can be formed by oxidation of gap-fill metal films. Metal is deposited on the structure of the hole or trench, and then oxidized to form the metal oxide. Volume expansion during oxidation pushes the pillar out of the hole or trench. The pillar grows selectively from the bottom up only from the metal.

[0004] Tungsten oxide has been used to form self-aligned pillars because it has high thermal expansion and high Young's modulus or stiffness. Tungsten oxide can be formed by oxidizing tungsten metal using oxygen at high temperature.

[0005] However, there are some challenges using this process because of the rate and amount of volume expansion of the metal to form the metal oxide pillars. First, the rapid change in pressure can sometimes cause degradation of the inherent structure. This can cause the pillars to bend or tilt. Second, the rapid change in volume can sometimes cause uneven growth. Third, residual unoxidized metal often remains at the bottom of the trench.

[0006] There is a need in the art for alternative methods of creating self-aligning structures. More specifically, there is a need in the art for alternative methods of creating self-aligning posts and structures to provide more rigid, stronger posts. Summary of the invention

[0007] One or more embodiments of the present disclosure are directed to a substrate processing method comprising the steps of providing a substrate having a substrate surface and having at least one feature formed in the substrate. The at least one feature extends from the substrate surface into the substrate by a distance, and the at least one feature has a sidewall and a bottom. A metal film is formed in the at least one feature. The metal film is exposed to a chalcogenide precursor to form metal chalcogenide pillars, the metal chalcogenide pillars extending from the at least one feature. The chalcogenide precursor is substantially free of oxygen.

[0008] Additional embodiments of the present disclosure relate to a method of processing a substrate, comprising the steps of providing a substrate having a substrate surface and having at least one feature formed in the substrate. The at least one feature extends from the substrate surface into the substrate by a distance, and the at least one feature has a sidewall and a bottom. Forming a metal film in the at least one feature. Expanding the metal film to form a column extending from the at least one feature. The column is substantially free of oxygen. Exposing the column to a chalcogenide precursor to form a metal chalcogenide column extending from the at least one feature. The chalcogenide precursor is substantially free of oxygen.

[0009] Further embodiments of the present disclosure relate to a method of processing a substrate, comprising the steps of providing a substrate having a substrate surface and having at least one feature formed in the substrate. The at least one feature extends from the substrate surface into the substrate by a distance, and the at least one feature has sidewalls and a bottom. Exposing the substrate to a metal chalcogenide precursor to form a metal chalcogenide column extending from the at least one feature. The metal chalcogenide precursor is substantially free of oxygen. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The manner in which the above-described features of the disclosure briefly summarized herein can be understood in detail, as well as a more detailed description of the disclosure, can be obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of the disclosure and thus should not be considered as limiting the scope of the disclosure, as the disclosure may admit to other equally effective embodiments.

[0011] Figure 1 a cross-sectional view showing substrate features according to one or more embodiments of the present disclosure; and

[0012] Figure 2 A schematic cross-sectional view showing a process for forming a self-aligned structure according to one or more embodiments of the present disclosure;

[0013] Figure 3 A schematic cross-sectional view showing a process for forming a self-aligned structure according to one or more embodiments of the present disclosure; and

[0014] Figure 4 A schematic cross-sectional view illustrating a process for forming a self-aligned structure according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0015] In the following description, many details such as materials, chemicals, dimensions of components, etc. are set forth in order to provide a thorough understanding of one or more embodiments of the present disclosure. A person of ordinary skill in the art will understand that one or more embodiments of the present disclosure may be implemented without these details. In other cases, details of semiconductor manufacturing processes, techniques, materials, equipment, etc. are not described to avoid unnecessarily obscuring the specification. With the included description, a person of ordinary skill in the art will be able to implement the appropriate functions without excessive experimentation.

[0016] Although certain exemplary embodiments of the present disclosure are described and shown in the accompanying drawings, it should be understood that these embodiments are merely illustrative and not restrictive of the present disclosure, and the present disclosure is not limited to the specific structures and arrangements shown and described, as modifications may be made by ordinary technicians in the technical field to which the case belongs.

[0017] References throughout this disclosure to "one embodiment," "another embodiment," or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of the present disclosure. Thus, phrases such as "in one embodiment" or "in an embodiment" appearing throughout this specification are not necessarily all referring to the same embodiment of the present disclosure. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0018] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0019] As used herein, "substrate" refers to any substrate or any material surface formed on a substrate on which film treatment is performed during a manufacturing process. For example, substrate surfaces on which treatment may be performed may include, depending on the application, materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire; and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates may include, but are not limited to, semiconductor wafers. The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam harden, and / or bake the substrate surface. In addition to performing film treatment directly on the surface of the substrate itself, in the present disclosure, any disclosed film treatment step may also be performed on an underlying layer formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is intended to include such underlying layers as indicated by the context. Thus, for example, when a film / layer or a portion of a film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0020] The inventors have discovered that other tungsten chalcogenides (e.g., tungsten sulfide or tungsten selenide) can be used instead of tungsten oxide pillars to form self-aligned vias. The inventors have also discovered that the metal can be changed and other metals (e.g., molybdenum) can be used instead. Thus, molybdenum sulfide and molybdenum selenide can also be used to form self-aligned pillars. Without being bound by theory, these materials are known to: (i) form nanorods, (ii) have high expansion coefficients relative to their metals, and (iii) form rigid and straight structures.

[0021] One or more embodiments of the present disclosure are directed to methods for forming self-aligned structures comprising metal chalcogenides. Some embodiments of the present disclosure advantageously provide methods for forming metal chalcogenide structures that are harder, stronger, less skewed, and exhibit more uniform growth than conventional metal oxide pillars. Some embodiments of the present disclosure advantageously provide methods for removing self-aligned structures to produce self-aligned vias.

[0022] Generally, chalcogenides include elements in Group 16 of the periodic table, including, but not limited to, oxygen, sulfur, and selenium. As used throughout this disclosure, "chalcogens" or "chalcogenides" refer to chalcogenides other than oxygen.

[0023] Figure 1A partial cross-sectional view of a substrate 100 is shown having a feature 110. As used herein, the term "feature" refers to any intentional surface irregularity. Suitable examples of features include, but are not limited to, a trench having a top, two sidewalls, and a bottom; a valley having a top and two sidewalls without a separate bottom; and a via having sidewalls extending downward from the surface and having an open bottom or a bottom formed of a different material than the sidewalls.

[0024] The figures show a substrate with a single feature for illustration purposes; however, one skilled in the art will appreciate that there may be more than one feature. The shape of feature 110 may be any suitable shape, including but not limited to: a groove and a cylindrical through hole.

[0025] Substrate 100 has a top surface 120. At least one feature 110 forms an opening in top surface 120. Feature 110 extends from top surface 120 to bottom surface 112 by a depth D. Feature 110 has a first sidewall 114 and a second sidewall 116 that define a width W of feature 110. The open area formed by the sidewalls and the bottom is also referred to as a gap.

[0026] In a specific embodiment, feature 110 is a trench. The feature can have any suitable aspect ratio (the ratio of the depth D of the feature to the width W of the feature). In some embodiments, the aspect ratio is greater than or equal to about 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, or 40:1.

[0027] See also Figure 2 , providing a substrate 200 for processing. The substrate 200 is similar to Figure 1 As used herein, the term "providing" means placing the substrate in a location or environment for further processing. In some embodiments, as Figure 2 As illustrated, substrate 200 has a first surface material 250 and a second surface material 260. First surface material 250 and second surface material 260 can be the same or different surface materials on substrate 200. In some embodiments, feature 210 is formed having a bottom surface 212 and a top surface 220, bottom surface 212 includes first surface 250 and sidewalls 214, 216, and top surface 220 includes second surface material 260.

[0028] In some embodiments, film 230 is formed on top surface 220 and sidewalls 214, 216 and bottom surface 212 of feature 210. Film 230 can be any suitable film formed by any suitable process including, but not limited to, chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, plasma enhanced atomic layer deposition, physical vapor deposition, and / or sputtering.

[0029] Film 230 may be any suitable metal-containing material. In some embodiments, film 230 is a metal-containing film. For purposes of the present disclosure and the appended claims, a metal-containing film is any film containing a metal species, and may include a metal film or a derivative of a metal film. A metal-containing film may contain only metal atoms. In some embodiments, film 230 is a metal film or a metal alloy film.

[0030] The metal-containing film may contain metal atoms and other atoms (e.g., oxygen, nitrogen, carbon, boron). Suitable metal-containing films include derivatives of metal films. Suitable derivatives of metal films include, but are not limited to, nitrides, borides, carbides, oxynitrides, oxyborides, oxycarbides, carbonitrides, borocarbides, boronitrides, borocarbonitrides, borooxycarbonitrides, oxycarbonitrides, borooxycarbides, and borooxynitrides.

[0031] Those skilled in the art will appreciate that metal-containing films may have non-stoichiometric amounts of atoms. For example, a film designated as WN may have different amounts of tungsten and nitrogen. A WN film may be, for example, 90 atomic % tungsten. Using WN to describe a tungsten nitride film means that the film includes tungsten and nitrogen atoms, and should not be considered to limit the film to a particular atomic composition. In some embodiments, the film consists essentially of the specified atoms. For example, a film consisting essentially of WN means that the composition of the film is greater than or equal to about 95%, 98%, 99%, or 99.5% tungsten and nitrogen atoms.

[0032] In some embodiments, the film 230 comprises one or more of: Co, Mo, W, Ta, Ti, Ru, Rh, Cu, Fe, Mn, V, Nb, Hf, Zr, Y, Al, Sn, Cr, Os, U, or La. In some embodiments, the film 230 consists essentially of Co, Mo, W, Ta, Ti, Ru, Rh, Cu, Fe, Mn, V, Nb, Hf, Zr, Y, Al, Sn, Cr, Os, U, or La. In some embodiments, the film 230 comprises one or more of: tungsten or molybdenum. In some embodiments, the film consists essentially of tungsten. In some embodiments, the film consists essentially of molybdenum. As used herein, the term "consisting essentially of" means that the recited material is greater than or equal to 98%, 99%, or 99.5% of the recited element, on an atomic basis.

[0033] Suitable metals for use in the metal-containing film include, but are not limited to, metals having a Pilling-Bedworth ratio greater than 2, greater than 2.25, or greater than 2.5. The Pilling-Bedworth ratio refers to the ratio of the volume of the elementary cell of the metal chalcogenide to the volume of the elementary cell of the corresponding metal-containing film forming the metal chalcogenide. The Pilling-Bedworth ratio is defined as V chalc / V metal , where V is the volume. For the Pilling-Bedworth ratio of metal chalcogenides, V chalc is equal to the molecular weight of the metal chalcogenide multiplied by the density of the metal chalcogenide, and V metal =The number of metal atoms per molecule of the metal chalcogenide multiplied by the atomic weight of the metal multiplied by the density of the metal chalcogenide. In some embodiments, the metal has a Pilling-Bedworth ratio greater than 1.5, greater than 1.75, greater than 2.0, greater than 2.25, or greater than 2.5.

[0034] In some embodiments, the film 230 can be removed from the top surface 220 such that the film 230 is completely contained within the feature 210. The film 230 can be removed by any suitable etching process. In some embodiments, the film 230 can be removed by a chemical mechanical planarization (chemical mechanical polishing) process.

[0035] In some embodiments, substantially all of the film 230 is formed within the feature 210. As used herein, the term "substantially all" means greater than or equal to about 95%, 98%, or 99% of the film is formed within the feature 210 by weight.

[0036] In some embodiments, the film 230 is selectively deposited within the features 210 and is not deposited on the top surface 220 of the substrate. In these embodiments, the substrate 200 may be processed to remove the substrate 200 from the substrate 200. Figure 1 Flow direction Figure 2 The second diagram will not be displayed Figure 2 One skilled in the art will recognize that the composition of the first surface material 250 and the second surface material 260 may be selected to promote selective deposition of the film 230 on one surface relative to another surface.

[0037] In some embodiments, the method includes selectively depositing a film 230 within the trench to a height H, wherein the height H is less than or equal to the depth D of the feature 210. In one embodiment, the film 230 fills at least 10% of the volume of the trench. In other embodiments, the film 230 fills at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% of the volume of the feature 210. In some embodiments, the film 230 deposited in the feature 210 has a height H less than or equal to about 98%, 95%, 90%, 80%, 70%, 60%, or 50% of the depth D of the feature 210.

[0038] The film 230 is exposed to a chalcogenide precursor to expand the material volume of the film 230 and provide a self-aligned structure 240 comprising a metal chalcogenide. The self-aligned structure may also be referred to as a metal chalcogenide pillar. The chalcogenide precursor may be any suitable material comprising a chalcogenide element that produces a film comprising a metal and a chalcogenide element. In some embodiments, the chalcogenide precursor is substantially free of oxygen. As used herein, "substantially free of oxygen" means that the chalcogenide precursor contains less than 1%, 0.5%, or 0.1% oxygen atoms, on an atomic basis. In some embodiments, the chalcogenide precursor comprises one or more of: H2S, alkyl sulfide, alkyl disulfide, S8 powder, and Se powder. In some embodiments, the H2S is generated in situ by the reaction of Na2S and dilute HCl. In some embodiments, the exposure and subsequent expansion are performed by a process comprising thermal, plasma enhanced, remote plasma, microwave, and / or radio frequency (e.g., ICP, CCP) reactions.

[0039] The self-aligned structure 240 extends beyond the top surface 220 of the substrate. In some embodiments, the self-aligned structure 240 comprises a metal chalcogenide. In this regard, the metal chalcogenide comprises metal atoms and chalcogenide atoms. In some embodiments, the metal chalcogenide of the self-aligned structure 240 comprises one or more of the following: sulfur, selenium, or tellurium. In some embodiments, the metal chalcogenide of the self-aligned structure 240 does not substantially comprise oxygen. In some embodiments, the metal chalcogenide of the self-aligned structure 240 may also comprise other atoms.

[0040] The volume of the self-aligned structures 240 is greater than the volume of the film 230. In some embodiments, the volume of the self-aligned structures 240 is greater than 1.25, greater than 1.5, greater than 1.6, greater than 1.7, greater than 1.75, greater than 1.8, greater than 1.9, greater than 2.0, or greater than 2.5 times the volume of the film. In some embodiments, the volume of the self-aligned structures is less than 3.0, less than 2.5, less than 2.0, less than 1.9, less than 1.8, less than 1.75, less than 1.7, less than 1.6, or less than 1.5 times the volume of the film. In some embodiments, the volume of the self-aligned structures is in the range of greater than 1 to less than 2 times the volume of the film within the features 210.

[0041] A plurality of self-aligned structures 240 may be formed to provide a plurality of self-aligned structures when a plurality of features are filled with film 230. In some embodiments, these self-aligned structures may be patterned without the use of masks.

[0042] like Figure 2 As shown, during expansion, the fidelity of the feature shape is maintained on the top of the feature, such that the film 230 grows straight up from the feature 210. As used herein, "straight up" means that the sides of the self-aligned structure 240 are substantially coplanar with the sidewalls 214, 216 of the feature 210. The surface is coplanar with the sidewall 214, wherein the angle formed where the sidewall 214 meets the surface is ±10°. In this regard, if the sidewall is perpendicular to the top surface, then the expanded film extending "straight up" from the feature can be described as normal to the top surface of the substrate.

[0043] See also Figure 3 , providing a substrate 300 for processing. The substrate 300 is similar to the substrates in Figure 1 and 2 The substrates 100 and 200 shown in FIG. are similar to those described above and shown in FIG. Figure 2 In some embodiments, the method Figure 3The substrate 300 is shown having a first surface material 350 and a second surface material 360. The first surface material 350 and the second surface material 360 can be the same or different surface materials on the substrate 300. In some embodiments, a feature 310 having a bottom surface 312 and a top surface 320 is formed, wherein the bottom surface 312 includes the first surface 350 and sidewalls 314, 316, and the top surface 320 includes the second surface material 360.

[0044] In some embodiments, film 330 is formed on top surface 320 and sidewalls 314, 316 and bottom surface 312 of feature 310. Film 330 can be any suitable film formed by any suitable process including, but not limited to, chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, plasma enhanced atomic layer deposition, physical vapor deposition, and / or sputtering. Film 330 is similar to film 230 described above.

[0045] In some embodiments, film 330 can be removed from top surface 320 such that film 330 is completely contained within feature 310. Film 330 can be removed by any suitable etching process. In some embodiments, film 330 is removed by a chemical mechanical planarization (CMP) process.

[0046] In some embodiments, substantially all of the film 330 is formed within the feature 310. In some embodiments, the film 330 is selectively deposited within the feature 310 and not on the top surface 320 of the substrate. In these embodiments, the substrate 300 may be processed so that it will Figure 1 Flow direction Figure 3 The second diagram will not be displayed Figure 3 One skilled in the art will recognize that the composition of the first surface material 350 and the second surface material 360 can be selected to promote selective deposition of the film 330 on one surface relative to another surface.

[0047] In some embodiments, the method includes selectively depositing film 330 within the trench to a height H that is less than or equal to a depth D of feature 310. In one embodiment, film 330 fills at least 10% of the volume of the trench. In other embodiments, film 230 fills at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% of the volume of feature 310. In some embodiments, film 330 deposited in feature 310 has a height H that is less than or equal to about 98%, 95%, 90%, 80%, 70%, 60%, or 50% of the depth D of feature 310.

[0048] The film 330 is exposed to a reactant to expand the volume of the material of the film 330 and provide pillars 340. The reactant can be any suitable material that produces pillars that include the metal of the film 330. In some embodiments, the reactant includes nitrogen and the expansion process is a nitridation process. In some embodiments, the reactant includes silicon and the expansion process is a silicidation process.

[0049] In some embodiments, the reactant comprises substantially no oxygen. In some embodiments, the column comprises substantially no oxygen. In some embodiments, the reactant comprises one or more of: N2, NH3, N2H4, or a plasma of the foregoing. In some embodiments, the reactant comprises one or more of: silane, disilane, trisilane, tetrasilane, pentasilane, hexasilane, trimethylsilane, a compound having a trimethylsilane substituent, dichlorosilane, trichlorosilane, trisilylamine, or a plasma of the foregoing.

[0050] In some embodiments, the exposure and subsequent expansion is performed by a process comprising thermal, plasma enhanced, remote plasma, microwave, and / or radio frequency (eg, ICP, CCP) reactions.

[0051] In some embodiments, a plasma source may be used to expand the film 330. The plasma may be generated remotely or in a processing chamber. The plasma may be an inductively coupled plasma (ICP) or a conductively coupled plasma (CCP). Depending on, for example, the composition of the film, the reactants, the predetermined expansion rate, or the predetermined amount of volume expansion, the treatment may occur at any suitable power. In some embodiments, the plasma power utilized for expansion of the film is in the range of about 2 kW to about 10 kW. In some embodiments, the plasma power utilized for expansion is greater than or equal to about 2 kW, 5 kW, or 8 kW. In some embodiments, the plasma power utilized for expansion is less than or equal to about 10 kW, 8 kW, or 5 kW. In some embodiments, the plasma power utilized for expansion is about 10 kW.

[0052] In some embodiments, the expansion membrane 330 may utilize microwaves or radio frequencies. Depending on, for example, the composition of the membrane, the reactants, the predetermined expansion rate, or the predetermined amount of volume expansion, the treatment may occur at any suitable frequency. In some embodiments, the membrane is expanded using a frequency in the range of about 2 MHz to about 100 MHz. In some embodiments, the expansion uses a frequency greater than or equal to about 2 MHz, 5 MHz, 10 MHz, 13.56 MHz, 25 MHz, 30 MHz, 40 MHz, 50 MHz, 60 MHz, 75 MHz, or 100 MHz. In some embodiments, the expansion uses a frequency less than or equal to about 100 MHz, 90 MHz, 75 MHz, 50 MHz, 40 MHz, 30 MHz, 25 MHz, 10 MHz, or 5 MHz. In some embodiments, the expansion uses a frequency of about 13.56 MHz.

[0053] In some embodiments, the rate at which the film expands to form pillars is controlled. In some embodiments, the amount of expansion is controlled. In some embodiments, the rate or amount of expansion is controlled by co-flowing hydrogen with the reactants. Without being bound by theory, it is believed that exposing the substrate to hydrogen slows the reaction by promoting competing reverse reactions and / or shifting the equilibrium of the reaction by introducing reaction products.

[0054] The hydrogen gas may be supplied to the processing chamber at any suitable flow rate, depending on, for example, the composition of the film, the reactants, the predetermined expansion rate, or the predetermined amount of volume expansion. In some embodiments, the hydrogen gas is provided at a flow rate in a range of greater than 0 sccm to about 5000 sccm. In some embodiments, the hydrogen gas is provided at a flow rate of about 1000 sccm.

[0055] In some embodiments, the rate or amount of expansion is controlled by exposing the self-aligned structure to a hydrogen plasma source. Without being bound by theory, it is believed that the hydrogen plasma removes reactant atoms (e.g., N or Si) from the pillars and returns the volume of the pillars toward the volume of the film before expansion.

[0056] Pillars 340 extend beyond the top surface 320 of the substrate. The volume of pillars 340 is greater than the volume of film 330. In some embodiments, the volume of pillars 340 is greater than 1.25, greater than 1.5, greater than 1.6, greater than 1.7, greater than 1.75, greater than 1.8, greater than 1.9, greater than 2.0, or greater than 2.5 times the volume of the film. In some embodiments, the volume of the self-aligned structure is less than 3.0, less than 2.5, less than 2.0, less than 1.9, less than 1.8, less than 1.75, less than 1.7, less than 1.6, or less than 1.5 times the volume of the film. In some embodiments, the volume of the self-aligned structure is in a range of greater than 1 to less than 2 times the volume of the film within feature 310.

[0057] like Figure 3 As shown, during expansion, the fidelity of the feature shape is maintained at the top of the feature, such that the film 330 grows straight up from the feature 310. As used herein, "straight up" means that the sides of the pillars 340 are substantially coplanar with the sidewalls 314, 316 of the feature 310. The surface is coplanar with the sidewall 314, wherein the angle formed where the sidewall 314 meets the surface is ±10°. In this regard, a pillar extending "straight up" from a feature can be described as being normal to the top surface of the substrate if the sidewall is perpendicular to the top surface.

[0058] Pillars 340 are exposed to a chalcogenide precursor to form self-aligned structures 370. Self-aligned structures 370 may also be referred to as metal chalcogenide pillars. The chalcogenide precursor may be any suitable material comprising a chalcogenide element, which converts the pillars into metal chalcogenide pillars. In some embodiments, the chalcogenide precursor is substantially free of oxygen. In some embodiments, the chalcogenide precursor comprises one or more of: H2S, alkyl sulfides, alkyl disulfides, S8 powder, and Se powder. In some embodiments, H2S is generated in situ by the reaction of Na2S and dilute HCl. In some embodiments, the exposure and subsequent conversion is performed by a process comprising thermal, plasma enhanced, remote plasma, microwave, and / or radio frequency (e.g., ICP, CCP) reactions.

[0059] In some embodiments, the self-aligned structure 370 comprises a metal chalcogenide. In this regard, the metal chalcogenide comprises metal atoms and chalcogenide atoms. In some embodiments, the metal chalcogenide of the self-aligned structure 370 comprises one or more of: sulfur, selenium, or tellurium. In some embodiments, the metal chalcogenide of the self-aligned structure 370 comprises substantially no oxygen. In some embodiments, the metal chalcogenide of the self-aligned structure 370 may comprise atoms other than the metal of the film 330 and the chalcogenide element of the chalcogenide precursor.

[0060] See also Figure 4 , providing a substrate 400 for processing. The substrate 400 is similar to the substrates shown in Figure 1 , 2 and 3 substrates 100, 200 and 300. Similar to the above and respectively Figure 2 and 3 The method shown in the figure, in some embodiments, Figure 4The substrate 400 is shown having a first surface material 450 and a second surface material 460. The first surface material 450 and the second surface material 460 can be the same or different surface materials on the substrate 400. In some embodiments, a feature 410 is formed having a bottom surface 412 and a top surface 420, the bottom surface 412 including the first surface 450 and sidewalls 414, 416, and the top surface 420 including the second surface material 460.

[0061] The substrate 400 is exposed to a metal chalcogenide precursor to form a self-aligned structure 440. The self-aligned structure may also be referred to as a metal chalcogenide pillar. The metal chalcogenide pillar comprises a metal chalcogenide. The metal chalcogenide precursor may be any suitable compound comprising a metal and a chalcogenide element, which produces a film comprising the metal and the chalcogenide element. The metal may be any suitable metal. In some embodiments, the metal chalcogenide pillar comprises one or more of: tungsten and molybdenum. In some embodiments, the metal chalcogenide pillar comprises one or more of: sulfur, selenium, or tellurium. In some embodiments, the metal chalcogenide precursor comprises substantially no oxygen.

[0062] In some embodiments, the metal chalcogenide precursor comprises a cation and a metal complex anion. In some embodiments, the cation comprises an ammonium cation, NR4 + , wherein each R is independently H or a C1-C4 alkyl group. As used in this manner, the letter "C" followed by a number (e.g., "C4") indicates that the substituent contains the specified number of carbon atoms (e.g., C4 contains four carbon atoms). The alkyl group can be a straight chain group (e.g., n-butyl) or a branched chain group (e.g., tert-butyl). In some embodiments, each R is hydrogen (NH4 + ). In some embodiments, each R is a methyl group. In some embodiments, the metal complex anion comprises a chalcogenide. In some embodiments, the metal complex anion comprises one or more of: a metal sulfide, a metal selenide, or a metal telluride.

[0063] In some embodiments, the metal chalcogenide precursor is of the general formula (R4N): x M a Z yIn some embodiments, the metal sulfide precursor comprises bis-tetraalkylammonium tetrathiotungstate ((H4N)2WS4), wherein each R is independently H or a C1-C4 alkyl group, M is a metal, Z is a chalcogenide element, and x, y, and a are integers from 1 to 6, so that the metal sulfide precursor is electrochemically neutral. In some embodiments, the metal sulfide precursor comprises ammonium tetrathiotungstate (bis-tetraalkylammonium tetrathiotungstate; (H4N)2WS4). In some embodiments, the metal sulfide precursor comprises tetraalkylammonium tetrathiotungstate ((R4N)2WS4), wherein each R is an independently selected C1-C4 alkyl group.

[0064] In some embodiments, the exposure and subsequent forming is performed by a process comprising thermal, plasma enhanced, remote plasma, microwave, and / or radio frequency (eg, ICP, CCP) reactions.

[0065] In some embodiments, the self-aligned structure 440 is selectively formed within the feature 410 and is not deposited on the top surface 420 of the substrate. Those skilled in the art will recognize that the composition of the first surface material 450 and the second surface material 460 can be selected to cause the self-aligned structure 440 to be selectively deposited on one surface relative to other surfaces.

[0066] like Figure 4 As shown, after formation, the fidelity of the feature shape is maintained on the top of the feature, so that the self-alignment structure 440 is formed straight up from the feature 410. As used herein, "straight up" means that the sides of the self-alignment structure 440 are substantially coplanar with the sidewalls 414, 416 of the feature 410. The surface is coplanar with the sidewall 414, wherein the angle formed where the sidewall 414 meets the surface is ±10°. In this regard, if the sidewall is perpendicular to the top surface, the self-alignment structure 440 extending "straight up" from the feature can be described as normal to the top surface of the substrate.

[0067] In some embodiments, after forming the self-aligned structure by any of the above methods, a material is deposited around the self-aligned structure. In some embodiments, the material is a dielectric material. In some embodiments, the material is the same as the first surface material or the second surface material. In some embodiments, the deposited material is an inter-layer dielectric (ILD).

[0068] In some embodiments, after depositing the material, the self-aligned structure is removed to form a self-aligned through hole. In some embodiments, the self-aligned structure is removed by exposing the self-aligned structure to an etchant. In some embodiments, the etchant comprises an alkaline solution. In some embodiments, the alkaline solution comprises one or more of: KOH, NaOH, or NH4OH. In some embodiments, the etchant is a metal halide etchant. In some embodiments, the etchant is a metal fluoride etchant. In some embodiments, the etchant comprises WF6. In some embodiments, the etchant is a metal chloride etchant. In some embodiments, the etchant comprises WCl5 or WCl6.

[0069] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations may be made to the methods and apparatus of the disclosure without departing from the spirit and scope of the disclosure. Therefore, it is intended that the disclosure include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A substrate processing method, comprising the following steps: forming a metal film on a substrate, the substrate having a top surface and having at least one feature formed in the substrate, the at least one feature extending from the top surface into the substrate by a distance, the at least one feature having sidewalls and a bottom, the metal film being formed in the at least one feature; and The metal film is exposed to a chalcogenide precursor that contains substantially no oxygen to form metal chalcogenide pillars that grow straight up over the at least one feature and have sidewalls above a top surface that are substantially coplanar with the sidewalls of the at least one feature or have sidewalls above the top surface that are orthogonal to the top surface.

2. The method of claim 1, wherein the metal comprises one or more of: tungsten and molybdenum.

3. The method of claim 1, wherein the chalcogenide precursor comprises one or more of the following: H2S, alkyl sulfide, alkyl disulfide, S8 powder, and Se powder.

4. The method of claim 1, wherein the metal chalcogenide pillars comprise one or more of: sulfur, selenium, or tellurium.

5. The method of claim 1, wherein the metal chalcogenide pillars are orthogonal to the top surface. 6 . The method of claim 1 , wherein a volume ratio of the metal chalcogenide pillars to the metal film is greater than or equal to about 2. 7 .

7. A method for producing a self-aligned through hole, the method comprising the steps of: Forming metal chalcogenide pillars according to claim 1; depositing a dielectric material on the top surface, the dielectric material surrounding the metal chalcogenide pillars; and The metal chalcogenide pillars are removed, leaving vias through the dielectric material.

8. A substrate processing method comprising the following steps: forming a metal film on a substrate, the substrate having a top surface and having at least one feature formed in the substrate, the at least one feature extending from the top surface into the substrate by a distance, the at least one feature having sidewalls and a bottom, the metal film being formed in the at least one feature; exposing the metal film to a reactant so that the material volume of the metal film expands and forms pillars, the pillars substantially free of oxygen, the pillars growing straight up over the at least one feature, having sidewalls above a top surface that are substantially coplanar with the sidewalls of the at least one feature, or having sidewalls above the top surface that are orthogonal to the top surface; and The pillars are exposed to a chalcogenide precursor that contains substantially no oxygen to form metal chalcogenide pillars.

9. The method of claim 8, wherein the metal comprises one or more of: tungsten and molybdenum.

10. The method of claim 8, wherein the pillars comprise one or more of: nitrogen, carbon, or silicon.

11. The method of claim 8, wherein the chalcogenide precursor comprises one or more of the following: H2S, dialkyl disulfide, S8 powder, and Se powder.

12. The method of claim 8, wherein the metal chalcogenide pillars comprise one or more of: sulfur, selenium, or tellurium.

13. The method of claim 8, wherein the metal chalcogenide pillars are normal to the substrate surface.

14. A method for producing a self-aligned through hole, the method comprising the steps of: Forming metal chalcogenide pillars according to claim 8; depositing a dielectric material on the surface of the substrate, the dielectric material surrounding the metal chalcogenide pillars; and The metal chalcogenide pillars are removed, leaving vias through the dielectric material.

15. A substrate processing method comprising the following steps: A substrate is exposed to a metal chalcogenide precursor to form metal chalcogenide pillars, the substrate having a top surface and having at least one feature formed in the substrate, the at least one feature extending a distance from the top surface into the substrate, and the at least one feature having sidewalls and a bottom, the metal chalcogenide pillars growing straight up above the at least one feature, having sidewalls above the top surface that are substantially coplanar with the sidewalls of the at least one feature, or having sidewalls above the top surface that are orthogonal to the top surface, and the metal chalcogenide pillars are substantially free of oxygen.

16. The method of claim 15, wherein the metal chalcogenide pillars comprise one or more of: tungsten and molybdenum.

17. The method of claim 15, wherein the metal chalcogenide pillars comprise one or more of: sulfur, selenium, or tellurium.

18. The method of claim 15, wherein the metal chalcogenide precursor is of the general formula (R4N): x M a Z y Represents, wherein each R is independently H or a C1-C4 alkyl, M is a metal, Z is a chalcogenide element, and x, y and a are integers from 1 to 6, so that the metal chalcogenide precursor is electrochemically neutral.

19. The method of claim 18, wherein the metal chalcogenide precursor comprises bis-tetraalkylammonium tetrathiotungstate ((R4N)2WS4), wherein R is a C1-4 alkyl group.

20. A method for producing a self-aligned through hole, the method comprising the steps of: Forming metal chalcogenide pillars according to claim 15; depositing a first material on the top surface, the first material comprising a dielectric, the first material surrounding the metal chalcogenide pillars; and The metal chalcogenide pillars are removed, leaving vias through the first material.

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