Atomic layer deposition of molybdenum-and-phosphorus-containing films

Abstract

Molybdenum-and-phosphorus-containing films are deposited in features. The films may be protective layers and bulk conductors. Atomic layer deposition (ALD) methods of depositing the films can include pulsing molybdenum pentachloride (MoCl5) and phosphine (PH3). The films may be selectively deposited on conductive surfaces to form thin protective layers. Bulk conductors having large grain size can be grown.

Description

Attorney Docket No. LAM1P147WO-12345-1WO ATOMIC LAYER DEPOSITION OF MOLYBDENUM-AND-PHOSPHORUS-CONTAINING FILMSINCORPORATION BY REFERENCE

[0000] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0001] Deposition of conductive materials is an integral part of many semiconductor fabrication processes. These materials may be used for horizontal interconnects, vias between adjacent metal layers, contacts between metal layers and devices, and as lines in memory devices.

[0002] The background description provided herein is forthe purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.SUMMARY

[0003] In some aspects, the techniques described herein relate to a method including: providing feature including an exposed conductive surface and an exposed dielectric surface; and selectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, leaving the dielectric surface exposed.

[0004] In some aspects, the techniques described herein relate to a method, wherein the conductive surface is a surface at a feature bottom and the dielectric surface is a feature sidewall surface.

[0005] In some aspects, the techniques described herein relate to a method, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is MoxPywith x + y being at least 0.99.

[0006] In some aspects, the techniques described herein relate to a method, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is between 50% and 95% (atomic) MoAttorney Docket No. LAM1P147WO-12345-1WO and between 5% and 50% (atomic) P.

[0007] In some aspects, the techniques described herein relate to a method, further including depositing a conformal molybdenum liner on the exposed dielectric surface and the molybdenum- and phosphorus-containing film.

[0008] In some aspects, the techniques described herein relate to a method, further including filling the feature with molybdenum.

[0009] In some aspects, the techniques described herein relate to a method, wherein the operations are performed in a single chamber.

[0010] In some aspects, the techniques described herein relate to a method, further including, selectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, exposing conductive surface to a metal halide to remove oxide from the conductive surface.

[0011] In some aspects, the techniques described herein relate to a method, wherein the conductive surface includes copper, molybdenum silicide, titanium carbide, or titanium aluminum carbide.

[0012] In some aspects, the techniques described herein relate to a method, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is no more than 30 Angstroms thick.

[0013] In some aspects, the techniques described herein relate to a method, further including filling the feature with molybdenum.

[0014] In some aspects, the techniques described herein relate to a method, further including selectively depositing molybdenum on the molybdenum (Mo)- and phosphorus (P)-containing film.

[0015] In some aspects, the techniques described herein relate to a method including: providing a feature to be filled with a conductive material; and depositing a molybdenum (Mo)-and phosphorus (P)-containing film in the feature by an atomic layer deposition (ALD) process including exposing the feature to doses of a molybdenum precursor and doses of a phosphorus-containing reactant.

[0016] In some aspects, the techniques described herein relate to a method, wherein the ALD process further includes exposing the feature to doses of hydrogen (H2).

[0017] In some aspects, the techniques described herein relate to a method, wherein the H2Attorney Docket No. LAM1P147WO-12345-1WO and phosphorus-containing reactant are co-flowed.

[0018] In some aspects, the techniques described herein relate to a method, wherein the doses of phosphorus-containing reactant and doses of H2 are delivered separately.

[0019] These and other aspects of the disclosure are described more fully with reference to the Figures.BRIEF DESCRIPTION OF FIGURES

[0020] Figures 1A-1D examples of material stacks featuring a substrate and a molybdenum-containing layer deposited thereon.

[0021] Figures 2A-2M shows example of features that molybdenum- and phosphorus-containing layers may be deposited in.

[0022] Figure 3 is an example of a feature that a molybdenum- and phosphorus-containing layer may be deposited in.

[0023] Figure 4A shows an example of deposition of a molybdenum-and-phosphorus-containing film by an atomic layer deposition (ALD) process.

[0024] Figure 4B shows examples of sequences of Mo-containing precursor, PH3, and optionally Hzto deposit MoP.

[0025] Figure 5 shows an example of XRD and XPS for one ALD deposition.

[0026] Figure 6A shows the structure after the fill, including a thin MoP layer on the left and, on the right, an embodiment in which MoP fills most of the feature prior to conformal Mo deposition.

[0027] Figure 6B shows an example of another process in which a thin MoP layer is deposited on a Cu layer.

[0028] Figure 6C shows an example of a process in which a thin layer of MoP is selectively deposited on Cu and TaN and not on surrounding low-k.

[0029] Figure 6D is plot comparing growth rate of MoP and Mo using M0CI5 as the molybdenum precursor.

[0030] Figure 7 is a plot showing selectivity of Mo deposition.

[0031] Figures 8, 9A, 9B, and 10 are examples of apparatus and system that may be used to implement the methods described herein.Attorney Docket No. LAM1P147WO-12345-1WO DETAILED DESCRIPTION

[0032] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

[0033] The subscripts "x" and "y" are used throughout the disclosure to denote a number greater than 0 that forms a stable compound. However, it should be noted that the lack of an "x" or other subscript (e.g., in titanium nitride (TIN) or titanium oxynitride (TiON)) does not imply a particular atomic ratio.

[0034] Provided herein are methods of filling features with molybdenum-and-phosphorus containing materials that may be used for logic and memory applications. The films may be deposited in semiconductor substrate features such as vias and trenches. The films may be deposited as liner layers and / or to fill features.

[0035] For ease of description, the disclosure refers chiefly molybdenum phosphide or MoP to denote molybdenum-and-phosphorus containing materials. MoP is used as a shorthand and is not limited to molybdenum monophosphide unless explicitly stated. More generally, the description of the methods, layers, films, and material stacks applies broadly to those that contain molybdenum and phosphorus, without reference to a particular stoichiometry, phase, or bonding state between the molybdenum and phosphorus. In some embodiments, MoP is or includes one or more of molybdenum monophosphide, M03P (tri-molybdenum phosphide), M0P2 (molybdenum diphosphide), and M0P4 (molybdenum tetraphosphide). The layers may include molybdenum and phosphorus in stoichiometric or non-stoichiometric ratios, as single or mixed phases, and amorphous, partially crystalline, or crystalline forms. Further, they include layers with chemically bonded molybdenum and phosphorus as well as layers with only partial or no bonding. The molybdenum-and-phosphorus-containing materials may be undoped or pure materials without other constituents other than trace impurities. In other embodiments, one or other constituents may be introduced to a MoP material.

[0036] Figures 1A and IB are schematic examples of material stacks that include molybdenum phosphide (MoP) layers according to various embodiments. Figures 1A and IB illustrate theAttorney Docket No. LAM1P147WO-12345-1WO order of materials in examples of particular stacks and may be used with any appropriate architecture and application, as described further below. Figure 1A shows a first material stack 111 featuring a substrate 102 and a molybdenum-containing layer 108 deposited thereon. The substrate 102 may be a silicon or other semiconductor wafer, e.g., a 200-mm wafer, a 300-mm wafer, or a 450-mm wafer, including wafers having one or more layers of material, such as dielectric, conducting, or semi-conducting material deposited thereon. In some embodiments, the substrate 102 may be or include silicon (Si) or silicon germanium (SiGe). The methods may also be applied to form metallization stack structures on other substrates, such as glass, plastic, and the like.

[0037] The stack 111 has a dielectric layer 104 on the substrate 102. The dielectric layer 104 may be deposited directly on a semiconductor surface (e.g., a Si or SiGe surface) of the substrate 102, or there may be any number of intervening layers. For example, the substrate 102 may include any number of layers deposited in various arrangements on a semiconductor surface.

[0038] Examples of dielectric layers include doped and undoped silicon oxide, silicon nitride, and aluminum oxide layers, with specific examples including doped or undoped layers of silicon nitride (SiN), silicon dioxide (SiO2), and aluminum oxide (AI2O3). The stack 111 has a layer 106 disposed between the molybdenum-containing layer 108 and the dielectric layer 104. The layer 106 may be a diffusion barrier and / or an adhesion layer, for example. A diffusion barrier is a layer that prevents diffusion of species between layers. An adhesion layer is a layer that promotes adhesion of a layer to an underlying layer. Examples of diffusion barrier and adhesion layers include titanium nitride (TIN), titanium / titanium nitride (Ti / TiN), tungsten (W), tungsten nitride (WN), and tungsten carbon nitride (WCN). The molybdenum-containing layer 108 is the main conductor of the structure. In some embodiments, the molybdenum-containing layer 108 may include multiple bulk layers deposited at different conditions. The molybdenum-containing layer 108 may or may not include a molybdenum nucleation layer. In the depicted example of Figure 1A, the molybdenum-containing layer 108 is deposited directly on the layer 106. In other embodiments (not depicted), the molybdenum-containing layer 108 may be deposited on a separate layer such as a growth initiation layer that includes another material, such as a tungsten (W) or W-containing growth initiation layer. The growth initiation layer may be used to facilitate nucleation and growth of the molybdenum-containing layer 108.

[0039] Figure IB shows another example of a stack 121. In this example, the stack 121 includes the substrate 102, dielectric layer 104, with molybdenum-containing layer 108 deposited directly on the dielectric layer 104, without an intervening diffusion barrier or adhesionAttorney Docket No. LAM1P147WO-12345-1WO layer. The molybdenum-containing layer 108 is as described with respect to Figure 1A. By using molybdenum-containing materials as the main conductor, low resistivity thin films can be obtained. Examples of low resistivity thin films include films with resistivity less than 40 uOhm-cm at 60 angstroms thickness and less than 15 uOhm-cm at 200 angstroms thickness.

[0040] In some embodiments, a stack may include the substrate, a conductive layer, and a molybdenum-containing layer deposited ontothe conductive layer. As used herein, a conductive layer is a layer having a conductivity of at least 104Q -cm1at room temperature. Examples include molybdenum on a metal layer (e.g., a W layer, another Mo layer, or a copper (Cu) layer). In these embodiments, there is no dielectric layer between the molybdenum layer and the conductive layer. Similarly, the stack may include molybdenum-containing material deposited directly on a metal compound layer. Examples include molybdenum-containing layer on a metal nitride layer (e.g., TiN, WN, or MoN). In still some other embodiments of a stack (not shown), the stack may include a substrate and a molybdenum-containing layer deposited directly on the substrate, including directly on a semiconducting surface, on a dielectric surface, or on a conductive surface.

[0041] Figure 1C shows another example of a stack 131. In this example, the stack 131 includes the substrate 102, a conductive layer 103, a molybdenum-containing layer 108, and an overlying conductive layer 103. The conductive layers 103 may be the same or different materials. Figure ID shows another layer example of a stack 141. In this example, the stack 141 includes the substrate 102, a dielectric layer 104, molybdenum-containing layer 108, and a conductive layer 103.

[0042] Figures 1A-1D illustrate examples ofthe order of materials in a particular stack and may be used with any appropriate architecture and application, with examples described further below.

[0043] In the examples of Figures 1A-1D, the molybdenum-containing layer 108 is or includes molybdenum phosphide (MoP). In some embodiments, the molybdenum-containing layer is a bilayer with MoP / Mo sub-layers (in either order). In some embodiments, the molybdenum-containing layer 108 contains multiple sub-layers of different molybdenum-containing materials, at least one layer being a MoP layer. Still further, in some embodiments, the MoP liner layers may be used as liner layers with another metal (e.g., W) used as the main conductor.

[0044] The methods described herein are performed on a substrate that may be housed in a chamber. The substrate may be a silicon or other semiconductor wafer, including wafers having one or more layers of material, such as dielectric, conducting, or semiconducting materialAttorney Docket No. LAM1P147WO-12345-1WO deposited thereon. The methods are not limited to semiconductor substrates and may be performed to fill any feature with molybdenum-containing material.

[0045] Figures 1A-1D illustrates examples of the order of materials in a particular stack and may be used with any appropriate architecture and applications. Examples of appropriate architecture and applications are described below with respect to Figures 2A-2L. The methods described herein are performed on a substrate that may be housed in a chamber. The substrate may be a silicon or other semiconductor wafer, including wafers having one or more layers of materials, such as dielectric, conducting, or semiconducting material deposited thereon. The methods are not limited to semiconductor substrates and may be performed to deposit a molybdenum layer in any feature.

[0046] Examples of features include vias, trenches, and contact holes. Features may be characterized by one or more narrow and / or re-entrant openings, constrictions within the feature, and high aspect ratios. A feature may be formed in one or more of the above-described stacks or layers within a stack. For example, the features may be formed at least partially in a dielectric layer. In some embodiments, a feature may have an aspect ratio of at least about 2:1, at least about 4:1, at least about 6:1, at least about 10:1, at least about 25:1, or higher. One example of a feature is a hole or via in a semiconductor substrate or a layer on the substrate.

[0047] Substrates may have features such as vias or contact holes, which may be characterized by one or more narrow and / or re-entrant openings, constrictions within the feature, and high aspect ratios. A feature may be formed in one or more of the above-described stacks or layers within a stack. For example, the feature may be formed at least partially in a dielectric layer. In some embodiments, a feature may have an aspect ratio of at least about 2:1, at least about 4:1, at least about 6:1, at least about 10:1, at least about 25:1, or higher. One example of a feature is a hole or via in a semiconductor substrate or a layer on the substrate.

[0048] Figure 2A depicts a schematic example of a DRAM architecture, including a Mo-containing buried wordline (bWL) 208 in a silicon substrate 202. The Mo bWL is formed in a trench etched in the silicon substrate 202. Lining the trench is a conformal barrier layer 206 and an insulating layer 204. The conformal barrier layer 206 is disposed between the insulating layer 204 and the silicon substrate 202. In this example, the insulating layer 204 may be a gate oxide layer formed from a high-k dielectric material such as a silicon oxide or silicon nitride material. In some embodiments disclosed herein, the conformal barrier layer 206 is TiN or a tungsten-containing layer, such as WN or WCN layer. In some embodiments, a conformal tungsten-containing growth initiation layer (not shown) may be present between the conformal barrierAttorney Docket No. LAM1P147WO-12345-1WO layer 206 and the molybdenum bWL 208. Alternatively, the Mo-containing bWL 208 may be deposited directly on a TiN or other diffusion barrier. In some embodiments, one or both of layers 204 and 206 is not present.

[0049] The bWL structure shown in Figure 2A is one example of an architecture that includes a molybdenum Mo-containing fill layer. During fabrication of the bWL, molybdenum-containing material is deposited into a feature that may be defined by an etched recess in the silicon substrate 202 that is conformally lined with layers 206 and / or 204, if present.

[0050] Figures 2B-2H are additional schematic examples of various structures into which molybdenum-containing material may be deposited in accordance with disclosed embodiments. Figure 2B shows an example of a cross-sectional depiction of a vertical feature 201 to be filled with a Mo-containing material. The feature can include a feature hole 205 in a silicon substrate 202. The feature hole 205 may have an underlayer 203 lining the sidewall or interior of the feature hole 205 and may form the interior surfaces. The feature hole 205 or other feature may have a dimension nearthe opening, e.g., an opening diameter or line width of between about 10 nm to 500 nm, for example, between about 25 nm and about 300 nm. The feature hole 205 can be referred to as an unfilled feature or simply a feature. The vertical feature 201, and any feature, may be characterized in part by an axis 218 that extends through the length of the feature, with vertically-oriented features having vertical axes and horizontally-oriented features having horizontal axes. The underlayer 203 can be, for example, a diffusion barrier layer, an adhesion layer, a nucleation layer, a combination of thereof, or any other applicable material. Non-limiting examples of underlayers can include dielectric layers and conducting layers. Examples of dielectric materials include oxides, such as SiC>2 and AI2O3; nitrides, such as SiN; carbides, such as nitrogen-doped silicon carbide (NDC) and oxygen-doped silicon carbide (ODC); and low k dielectrics, such as carbon-doped SiO2. In particular implementations, an underlayer can be one or more of titanium, titanium nitride, tungsten nitride, titanium aluminide, tungsten, and molybdenum. In some embodiments, the under-layer is tungsten-free. In some embodiments, the underlayer is molybdenum-free.

[0051] In some embodiments, features are wordline features in a 3D NAND structure. For example, a substrate may include a wordline structure having an arbitrary number of wordlines (e.g., 50 to 450) with vertical channels at least 200A deep. Examples of wordline features are described further below. Another example of a feature is a trench in a substrate or layer. Features may be of any depth. In various embodiments, the feature may have an underlayer, such as a barrier layer or adhesion layer. Non-limiting examples of underlayers include dielectricAttorney Docket No. LAM1P147WO-12345-1WO layers and conducting layers, e.g., silicon oxides, silicon nitrides, silicon carbides, metal oxides, metal nitrides, metal carbides, and metal layers.

[0052] Figure 2C shows an example of a vertical feature 201 that has a re-entrant profile. A reentrant profile is a profile that narrows from a bottom, closed-end, or interior of the feature to the feature opening. According to various implementations, the profile may narrow gradually and / or include an overhang at the feature opening. Figure 2C shows an example of the latter, with an underlayer 213 lining the sidewall or interior surfaces of the feature hole 205. Similarto Figure 2B, the underlayer 213 can be a diffusion barrier layer, an adhesion layer, a nucleation layer, a combination of thereof, or any other applicable material. Non-limiting examples of under-layers can include dielectric layers and conducting layers. The underlayer 213 forms an overhang 215 such that the underlayer 213 is thicker near the opening of the vertical feature 201 than inside the vertical feature 201.

[0053] In some implementations, features having one or more constrictions within the feature may be filled. Figure 2D shows examples of views of various filled features having constrictions. Each of the examples (a), (b), and (c) in Figure 2D includes a constriction 209 at a midpoint within the feature. The constriction 209 can be, for example, between about 15 nm-20 nm wide. Constrictions can cause pinch off during deposition of molybdenum in the feature using conventional techniques, with deposited metal blocking further deposition past the constriction before that portion of the feature is filled, resulting in voids in the feature. Example (b) further includes an overhang 215 (such as, a liner / barrier overhand) at the feature opening. Such an overhang could also be a potential pinch-off point. Example (c) includes a constriction 212 further away from the field region than the overhang 215 in example (b).

[0054] Horizontal features, such as in 3-D memory structures, can also be filled. Figure 2E shows an example of a horizontal feature 250 that includes a constriction 251. For example, horizontal feature 250 may be a word line in a 3-D NAND (also referred to as vertical NAND or VNAND) structure. In some implementations, the constrictions can be due to the presence of pillars in a 3D NAND or other structure. Figure 2F presents a cross-sectional side view of a 3-D NAND structure 210 (formed on a silicon substrate 202) having 3-D NAND stacks (left 225 and right 226), central vertical structure 230, and a plurality of stacked horizontal wordline features 220 with openings 222 on opposite sidewalls 240 of central vertical structure 230. Note that Figure 2F displays two "stacks" of the exhibited 3-D NAND structure 210, which together form the "trench-like" central vertical structure 230. However, in certain embodiments, there may be more than two such stacks arranged in sequence and running spatially parallel to one another,Attorney Docket No. LAM1P147WO-12345-1WO the gap between each adjacent pair of stacks forming a central vertical structure 230, like that explicitly illustrated in Figure 2F. In this embodiment, the horizontal wordline features 220 are 3-D memory wordline features that are flu idically accessible from the central vertical structure 230 through the openings 222. Although not explicitly indicated in the figure, the horizontal wordline features 220 present in both the 3-D NAND stacks 225 and 226 shown in Figure 2F (i.e., the left 3-D NAND stack 225 and the right 3-D NAND stack 226) are also accessible from the other sides of the stacks (far left and far right, respectively) through similar vertical structures formed by additional 3-D NAND stacks (to the far left and far right, but not shown). Each 3-D NAND stack 225, 226 contains a stack of wordline features that are flu id ica lly accessible from both sides of the 3-D NAND stack through a central vertical structure 230. In the particular example schematically illustrated in Figure 2F, each 3-D NAND stack contains 6 pairs of stacked wordlines. However a 3-D NAND memory layout may contain any number of vertically stacked pairs of wordlines.

[0055] The wordline features in a 3-D NAND stack can be formed by depositing an alternating stack of silicon oxide and silicon nitride layers, and then selectively removing the nitride layers leaving a stack of oxides layers having gaps between them. These gaps are the wordline features. Any number of wordlines may be vertically stacked in such a 3-D NAND structure so long as there is a technique for forming them available, as well as a technique available to successfully accomplish (substantially) void-free fills of the vertical features. Thus, for example, a VNAND stack may include between 2 and 512 horizontal wordline features, between 2 and 256 horizontal wordline features, between 8 and 128 horizontal wordline features, or between 16 and 64 horizontal wordline features, and so forth (the listed ranges understood to include e the recited endpoints).

[0056] Figure 2G presents a cross-sectional top-down view of the same 3-D NAND structure 210 shown in the side view in Figure 2F with the cross-section taken through the horizontal section 260 as indicated by the dashed horizontal line in Figure 2F. The cross-section of Figure 2G illustrates several rows of pillars 255, which are shown in Figure 2F to run vertically from the base of the substrate 202 to the top of the 3-D NAND structure 210. In some embodiments, the pillars 255 are formed from a polysilicon material and are structurally and functionally significant to the 3-D NAND structure 210. In some embodiments, such polysilicon pillars may serve as gate electrodes for stacked memory cells formed within the pillars. The top-view of Figure 2G illustrates that the pillars 255 form constrictions in the openings 222 to wordline features 220. Fluidic accessibility of wordline features 220 from the central vertical structure 230Attorney Docket No. LAM1P147WO-12345-1WO via openings 222 (as indicated by the arrows in Figure 2G) is inhibited by pillars 255. In some embodiments, the size of the horizontal gap between adjacent polysilicon pillars is between about 1 and 20 nm. This reduction in fluidic accessibility increases the difficulty of uniformly filling wordline features 220 with material. The structure of wordline features 220 and the challenge of uniformly fillingthem with molybdenum material due to the presence of pillars 255 is further illustrated in Figures 2H, 21, and 2J.

[0057] Figure 2H exhibits a vertical cut through a 3-D NAND structure similar to that shown in Figure 2F, but here focused on a single pair of wordline features 220 and additionally schematically illustrating a fill process which resulted in the formation of a void 275 in the filled wordline features 220. Figure 21 also schematically illustrates void 275, but in this figure illustrated via a horizontal cut through pillars 255, similartothe horizontal cut exhibited in Figure 2G. Figure 2J illustrates the accumulation of molybdenum material around the constrictionforming pillars 255, the accumulation resulting in the pinch-off of openings 222, so that no additional molybdenum-containing material can be deposited in the region of voids 275. Apparent from Figures 2H and 21 is that void-free molybdenum fill relies on migration of sufficient quantities of deposition precursor down through central vertical structure 230, through openings 222, past the constricting pillars 255, and into the furthest reaches of wordline features 220, prior to the accumulated deposition of molybdenum around pillars 255 causing a pinch-off of the openings 222 and preventing further precursor migration into wordline features 220. Similarly, Figure 2J exhibits a single wordline feature 220 viewed cross-sectionally from above and illustrates how a generally conformal deposition of molybdenum-containing material begins to pinch-off the interior of wordline feature 220 due to the fact that the significant width of pillars 255 acts to partially block, and / or narrow, and / or constrict what would otherwise be an open path through wordline feature 220. (It should be noted that the example in Figure 2J can be understood as a 2-D rendering of the 3-D features of the structure of the pillar constrictions shown in Figure 21, thus illustrating constrictions that would be seen in a plan view rather than in a cross-sectional view.)

[0058] Three-dimensional structures may need longer and / or more concentrated exposure to precursors to allow the innermost and bottommost areas to be filled. Three-dimensional structures can be particularly challenging when employing molybdenum halide and / or molybdenum oxyhalide precursors because of their proclivity to etch, with longer and more concentrated exposure allowing for more etch as parts of the structure.

[0059] Figures 2K and 2L show examples of an asymmetric trench structure DRAM bWL. SomeAttorney Docket No. LAM1P147WO-12345-1WO fill processes for DRAM bWL trenches can distort the trenches such that the final trench width and resistance Rs are significantly non-uniform. Figure 2K shows an unfilled feature 261 and filled feature 265 that exhibits line bending after fill. In this example, the features are a narrow asymmetric trench structure DRAM bWL. As shown, multiple features 283 are depicted on a substrate. These features 283 are spaced apart, and in some embodiments, adjacent features have a pitch between about 20 nm and about 60 nm or between about 20 nm and 40 nm. The pitch is defined as the distance between the middle axis of one feature to the middle axis of an adjacent feature. The unfilled features 261 may be generally V-shaped, as shown in feature 283, having sloped sidewalls where the width of the feature narrows from the top of the feature to the bottom of the feature. The features widen from the feature bottom 273b to the feature top 273a. After some fill operations, line bending may be observed within the filled feature 265. In some situations, a cohesive force between opposing surfaces of a trench pulls the trench sides together, as depicted by arrows 267. This phenomenon is illustrated in Figure 2L and may be characterized as "zipping up" the feature. As the feature 283 is filled, more force is exerted from a center axis 299 of the feature 283, causing line bending. For example, molybdenum may be deposited on the sidewalls of the feature 283. Deposited molybdenum 284a and 284b on sidewalls of feature 283 thereby interact in close proximity, where molybdenum-molybdenum bond radius r is small, thereby causing cohesive interatomic forces between the smooth growing surfaces of molybdenum and pulling the sidewalls together, thereby causing line bending.

[0060] Figure 2M shows an example of a 3D DRAM structure that may be filled using the method described herein. In the example shown, the features include an innermost surface 293, which may be a nitride, and dielectric sidewall surfaces 295. Example dimensions of the features are between about 10 nm and 20 nm width and between about 150 nm and 250 nm depth. In a 3D DRAM structure, there may be up to hundreds features to be filled. The main surface of substrate 296 can extend in the x and y directions, with Figure 2L oriented in the z-direction. In various embodiments, the feature may have an under-layer, such as a barrier layer or adhesion layer. Non-limiting examples of under-layers include dielectric layers and conducting layers, e.g., silicon oxides, silicon nitrides, silicon carbides, metal oxides, metal nitrides, metal carbides, metal silicides, and metal layers.

[0061] In some embodiments, the methods involve bottom-up deposition of a Mo-containing material in a feature. Bottom-up deposition refers to growth that is mostly or wholly from a feature bottom relative to the feature sidewalls. In some embodiments, the feature bottom is a conductive material, with the Mo-containing material deposited selectively thereon. As usedAttorney Docket No. LAM1P147WO-12345-1WO herein, a conductive layer is a layer having a conductivity of at least 104Q '-cm1at room temperature. Examples include molybdenum on a metal layer (e.g., a W layer, or another Mo layer). Bottom-up deposition is distinguished from filling a feature by nucleation and growth on all feature surfaces. This results in conformal growth and can result in the formation of a void and / or seam in the feature. For example, a void may form as growth at the top of the feature can pinches off the feature. A seam can form in the center of a feature as film grows inward from the sidewalls. Bottom-up deposition can avoid formation of voids and seams in the feature during the fill process. References to bottom-up deposition include inside-out deposition for horizontally-oriented features in which growth proceeds from the interior of a feature outward. An example of such a feature is shown in Figure 2M.

[0062] Molybdenum-and-phosphorus-containing films have high carrier concentration and relatively low bulk resistivities. For example, molybdenum monophosphide is a topological semimetal (TSM) that has a high carrier concentration ("1023 cm'3) and relatively low bulk resistivity (about 9 p-ohm-cm). Provided herein are low temperature ALD methods to deposit molybdenum-and-phosphorus-containing films, also referred to as MoP films. The low temperature methods allow MoP films to be used in interconnect metallization. Also provided are metallization processes that include ALD of MoP films.

[0063] In some embodiments, the methods are used to fill features to contact an underlying conductive contact. An example of such a feature is shown in Figure 3. At 301, an unfilled feature 312 is shown. The unfilled feature 312 is formed in an oxide layer 305 and is to be filled with Mo to make electrical contact with an underlying conductive contact 303. The unfilled feature 312 is defined by sidewall surfaces 315 and bottom surface 317. The conductive contact 303 may be, e.g., an elemental metal or a metal silicide in some embodiments.

[0064] According to various embodiments, the sidewall surfaces 315 and the bottom surface 317 may be the same or different materials. In some embodiments, the oxide layer 305 may be exposed to form the sidewall surfaces 315. Similarly, the underlying conductive contact 303 may be exposed to form the bottom surface 317. In some embodiments, surface oxidation may result in the bottom surface 317 being a metal oxide. In some embodiments, a liner layer (not shown) may be formed on the sidewall and / or bottom of the feature to form the sidewall surfaces 315 and / or bottom surface 317. Examples of liner layers include TiN, WN, and WCN. In some embodiments, a liner layer may be a molybdenum-containing liner layer such as a molybdenum nitride (MoN) layer.

[0065] In some embodiments, the sidewall surfaces 315 and bottom surface 317 are different.Attorney Docket No. LAM1P147WO-12345-1WO In a subsequent deposition operation, Mo may be deposited at conditions under which it preferentially nucleates on the bottom surface 317. This can promote bottom-up fill and prevent the formation of voids.

[0066] Examples of underlying metals and / or bottom surfaces include TiN, titanium aluminum carbide (TiAIC), Ti, W, Co, Mo, Ru, Cu, nickel (Ni), iridium (Ir), rhodium (Rh), tantalum (Ta), tantalum nitride (TaN), titanium silicide (TiSij), cobalt, cobalt silicide (CoSi?), and nickel silicide (NiSi).

[0067] Feature fill using molybdenum-and-phosphorus-containing films and ALD of molybdenum-and-phosphorus-containing films is described below with reference to Figures 4A, 4B, 5, 6A-6D, and 7. The methods may be performed using apparatus as shown in Figures 8, 9A, 9B, and 10. Each of these figures is described in detail further below. However, a brief overview of an apparatus as discussed in Figure 8 is provided for ease of reference in the discussion of Figures 4A, 4B, 5, 6A-6C, and 7.

[0068] The methods described herein employ vapor deposition using a molybdenum precursor and a co-reactant. Figure 8 depicts an example of a deposition process station 800 that may be used. The deposition process station 800 includes a process chamber 802 for maintaining a low-pressure environment. Reactants may be delivered from reactant delivery system 801a to a showerhead 806. The showerhead 806 includes ports for distributing process gases to substrate 812. The reactant delivery system 801a includes a mixing vessel 804 for blending and / or conditioning process gases, such as a Mo precursor-containing gas, a hydrogen-containing gas, an argon or other carrier gas, or other reactant-containing gas, for delivery to showerhead 806. One or more mixing vessel inlet valves 820 may control introduction of process gases to mixing vessel 804. Reactant delivery system 801a may also include one or more solid precursor delivery components including one or more on-board ampoules 813 and / or bulk delivery components 815. In some embodiments, for example, a solid Mo precursor such as molybdenum pentachloride (M0CI5) can be delivered from ampoule 813.

[0069] Figure 4A shows an example of deposition of a molybdenum-and-phosphorus-containing film by an atomic layer deposition (ALD) process. In the example of Figure 4A, a substrate may be provided to a semiconductor processing tool as described further below. For example, a substrate 812 may be provided to a process chamber 802 as in Figure 8. In some embodiments, the substrate is provided to a semiconductor processing tool for pre-treatment and subsequent deposition under common vacuum. This allows the substrate to be processed without air break and further oxidation. The substrate may include features formed in a dielectricAttorney Docket No. LAM1P147WO-12345-1WO layer and having exposed conductive surfaces as described above. In some embodiments, an oxide layer may be formed on the conductive surfaces. Also as described above, the features may have dielectric sidewalls.

[0070] At 401, a process gas including a molybdenum precursor is introduced to the process chamber 802 via showerhead 806. A purge operation is then performed in an operation 403 by flowing argon or other inert gas through showerhead 806. This removes gas-phase precursor, leaving an adsorbed layer of molybdenum-containing precursor on the substrate 812. At an operation 405, a phosphorus-containing reactant is introduced to process chamber 802. The phosphorus-containing reactant may be a reducing agent such as phosphine (PH3). In plasma processes using a direct plasma, the plasma is ignited during this operation. In plasma processes using a direct plasma, reactant includes plasma species (e.g., hydrogen radicals) generated remotely. The reactant reacts with the adsorbed precursor to form a layer of molybdenum phosphide. A purge operation is then performed in an operation 407 by flowing argon or other inert gas through showerhead 806. At an operation 409, operations 401-407 may then be repeated until the molybdenum film is at a target thickness.

[0071] Modifications of the process described in Figure 4A can include exposure to the phosphorus-containing reactant as the first operation in each cycle, followed by a purge, exposure to the molybdenum-containing compound, and purge. In such embodiments, a cycle can proceed by the following sequence: operation 405, 407, 401, and 403. One or both of operations 401 and 405 can be repeated multiple times in any cycle before the other operation is performed.

[0072] Further modifications can include each cycle forming less than a monolayer. This can be performed by limiting the amount of one or both reactants. In some embodiments, the ALD process may not be strictly self-limiting. For example, one or both of the purge operations may be omitted or shortened such that some gas-phase reactant remains and reacts in the gas phase. This can increase deposition rate. Further modifications can include repeating operation 401 (with or without an intervening purge) priorto performing operation 405 within a cycle. In some embodiments, operation 405 is repeated one or more times within a cycle. Such modifications facilitate diffusion through a feature.

[0073] In some embodiments, hydrogen (H2) is also used as a co-reactant. In such embodiments, it may be delivered with PH3 or other phosphorus-containing reactant (e.g., coflowed with it) and / or provided as an additional dose in the ALD cycle. Figure 4B shows examples of sequences of Mo-containing precursor (labeled as Mo in Figure 4B), PH3, and optionally H2 toAttorney Docket No. LAM1P147WO-12345-1WO deposit MoP. Argon (Ar) purges are also shown. Other Mo-containing precursors, phosphorus-containing reactants, and purge gases may be employed in these sequences according to various embodiments. In the examples of Figure 4B, each sequence is shown performed for N cycles, where N is an integer of at least 1. Example values of N range from 2 to 10 or 3 to 7 in some embodiments to deposit a MoP liner layer. A flow sequence can remain the same or change from cycle to cycle. In some embodiments, pressurized distribution of one or more reactants may be employed. To fill a feature, more cycles may be employed.

[0074] As shown in Figure 4B, in some embodiments, a PH3is co-flowed with H2. In the same or other embodiments, the PH3 may be co-flowed with N2. Reactant co-flow may have one or more of the following advantages: improve film purity by reducing oxygen impurity, increase throughput by increasing growth rate with negligible nucleation delay, and improving step coverage.

[0075] Substrate temperature during the deposition may range from 300°C to 6OO0C, e.g., 350C to 650C. Chamber pressure may be from 1 to 200 Torr, e.g., 10 to 50 Torr. PH3 may be delivered in a carrier gas, e.g., 10% PH3 in N2. It may co-flowed with argon and / or H2. Example flows are given below:• PH3(10% in N2) -5 sccm• Ar 100 seem• F sccm

[0076] If provided, H2 may be provided in significantly higher amounts than PH3. For example, for a 10% PH3flow, the H2:PH3volumetric flow ratio may be at least 2:1; at least 5:1, at least 10:1; at least 10:1; or at least 20:1

[0077] In the ALD processes described herein, the resulting MoP films may have mixed phases and / or contain some quantity of unbonded phosphorus and molybdenum. The MoP liner layers may be characterized by the relative amounts of Mo and P in some embodiments including bonded and unbonded Mo and P in various phases.

[0078] Figure 5 shows an example of XRD and XPS for one ALD deposition. The deposited film is composed of mainly MoP phase at 7.3 g / cm3- close to bulk density. Grain size is large (e.g., average grain size may be at least 10 nm or at least 15 nm).

[0079] The phosphorus content in the MoP layers described herein can vary from 1% to over 40%. In some embodiments, thin MoP layers (e.g., less than 15 Angstroms) may have P content at the lower end of this range, while the P content is higher for thicker layers. This is because thin layers may be discontinuous and Mo-rich. As the MoP layer grows, the P content increases,Attorney Docket No. LAM1P147WO-12345-1WO reaching saturation.

[0080] In some embodiments, the MoP films are highly pure films. In some embodiments, they are characterized as MoxPywith x + y equal to 1 to the nearest 0.01. For example, a film may have 60% Mo (x is 0.6) and 40% P (y is 0.4). Often molybdenum monophosphide (Moo.sPo.s) is deposited, but other crystalline phases or amorphous films including Mo-rich or P-rich amorphous films can be deposited. A film may be crystalline, amorphous, or have regions of different phases and / or concentrations. In some embodiments, the MoP film is between 50% and 90% Mo and between 10% and 50% P, with the percentages being atomic percentages. Films that are more Mo-rich may be deposited, especially if they are thin. In some such embodiments, MoP films having P content of less than 10% (y < 0.1), for example between 0.01 and 0.1, or 0.01 and 0.05, or between 0.5 and 0.1 may be deposited. For example, y may be as low 0.01, or 0.02 in some embodiments.Metallization

[0081] Figures 6A-6C illustrating example operations in methods for metallization. In Figure 6A, the process begins with providing a feature having SiCh dielectric sidewalls and a metalcontaining contact. The metal-containing contact may be at the bottom of the feature with the dielectric sidewalls extending from the feature opening to the metal-containing contact. The feature may be provided to a processing chamber. In some embodiments, one or more processing operations may occur in the processing chamber to form the feature having dielectric sidewalls and a metal-containing containing contact.

[0082] Examples of dielectric sidewalls include silicon-containing layers such as oxides and nitrides. Examples of metal-containing contacts include metals and metal compound films. The metal-containing contact may be generally conductive, having a conductivity of at least 104Q-1-cm1at room temperature. Examples include TiN, TiAIC, W, Co, Mo, Ru, Cu, Ni, Rh, Ir, Ta, Ti, TiSix, RuSix, NiPtSix, TiSiN, MoSix, CoSix. and TaN.

[0083] In some embodiments, a contact may have multiple exposed surfaces. For example, it may have exposed TiAIC and TiN. In some embodiments, a feature may include semiconducting (e.g., a-Si) and / or high-k dielectric surfaces. In such cases, the MoP can be selectively deposited on the conductive surfaces with reference to these surfaces.

[0084] In some embodiments, a surface oxide is present on the metal-containing contact. Still further, in some embodiments, a layer containing other impurities is present on the metalcontaining contact.Attorney Docket No. LAM1P147WO-12345-1WO

[0085] In some embodiments (not shown) an etch operation to remove a liner layer from at least the sidewalls of the feature is performed prior to operation. For example, a feature may include a TiN liner layer conformally coating the bottom and sidewalls. An etch may be performed to remove the TiN layer from the sidewalls, exposing dielectric material. The sidewall surfaces are then silicon oxide or other dielectric material.

[0086] A degas / pre-clean operation may be performed. This can remove surface oxide and / or etch residue, for example. Examples of etch residue include fluorocarbons and hydrocarbon polymers. According to various embodiments, this involves exposure to a molybdenum halide gas and / or a plasma clean.

[0087] A plasma clean may be remotely generated or generated in-situ. In some embodiments, a preclean involves exposure to a reducing plasma such as a H2plasma. In some embodiments, the preclean treatsthe dielectric sidewalls. For example, it may remove organic materials and / or reduce oxygen in the dielectric sidewalls. This can improve subsequent Mo growth selectivity on a metal-containing surface with respect to the sidewalls.

[0088] In some embodiments, the clean involves exposure to a molybdenum halide gas, e.g., M0CI5. This may be a plasma-free operation. Plasma-free refers to the operation performed without activating a plasma. Exposure to a molybdenum halide can remove impurities from the metal contact. In the same or other embodiments, exposure to a molybdenum halide inhibits nucleation on the dielectric sidewall surfaces.

[0089] In some embodiments, a molybdenum chloride compound is used. Molybdenum-containing compounds are also referred to herein as Mo-containing precursors or Mo precursors. Molybdenum chlorides are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (MoCI2), molybdenum trichloride (M0CI3), molybdenum tetrachloride (M0CI4), molybdenum pentachloride (M0CI5), and molybdenum hexachloride (MoCk). In some embodiments, M0CI5 or MoCk are used. While the description chiefly refers to MoClxcompounds, in other embodiments, other molybdenum halides may be used. Molybdenum halide precursors are given by the formula MoXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. Examples of MoXzprecursors include molybdenum fluoride (MoFg). In some embodiments, a non-fluorine-containing MoXzprecursor is used to prevent fluorine etch or incorporation. In some embodiments, a non-bromine-containing and / or a non-iodine-containing MoXzprecursor is used to prevent etch or bromine or iodine incorporation.

[0090] In some embodiments, the preclean involves exposure to the molybdenum halideAttorney Docket No. LAM1P147WO-12345-1WO compound without a co-reactant gas. In such embodiments, the molybdenum halide may be pulsed or delivered in a continuous dose. For examples, MoClsmay be pulsed with argon (Ar) other inert gas for a certain number of cycles. Alternatively, a continuous dose of M0CI5 can be delivered followed by an Ar purge.

[0091] In addition to or instead of any of the operations described above, a preclean can involve an atomic layer clean with a chlorine-based plasma, a hydrogen fluoride (HF) vapor clean, an ammonium fluoride (NH4F) clean, or a treatment using other reducing agents. These operations may be used to reduce oxide off a feature surface.

[0092] The process continues at with selective deposition of a MoP layer on the metalcontaining contact. The selective deposition deposits a layer on the metal-containing without significant deposition on the dielectric sidewalls. At the conditions described above, ALD deposits negligibly on dielectrics such as SiCh, SiN, and low-k compared to conductive materials (W, Mo, TiN, etc.). In some embodiments, MoCk as the molybdenum precursor.

[0093] Next, a Mo layer may be selectively deposited on the MoP in an optional operation. Process conditions such asthe precursor gas, the reducing agent, substrate temperature, process pressure, and exposure time may affect the selectivity of the Mo film being deposited. Different precursor gases may have different process windows in which Mo film may be selectively deposited. For example, M0CI5 is selective while MOO2CI2 is not, i.e., under the same temperature and pressure conditions, the precursor gas of M0CI5 may deposit Mo only on a conductive surface and not on a dielectric surface while a precursor gas of MOO2CI2 will deposit Mo on both conductive and dielectric surfaces. Generally speaking, MoCIsgas has a large process window, i.e., large temperature and pressure range, where the precursor gas retains its selectivity. For example, M0CI5 may be selectively deposited on a metal material with respect to a dielectric material where the process temperature is 300°C to 800°C. In some embodiments, the substrate temperature is 350°C to 550°C. Generally speaking, higher process temperatures and higher process pressures reduce the selectivity of the deposited film. For example, at higher temperatures, a precursor gas such as M0CI5 may lose its selectivity and deposit Mo film on both a metal surface and dielectric surface within a feature.

[0094] It can be easier to achieve selectivity with a thermal process. In some such embodiments, selective deposition of Mo can involve a pulsed chemical vapor deposition (pulsed CVD) process.

[0095] Returning to Figure 6A, a conformal Mo film may then be deposited. The conformal Mo liner is deposited by a non-selective method that deposits on both the MoP or M0P / M0 layerAttorney Docket No. LAM1P147WO-12345-1WO and the dielectric sidewalls and field regions. In some embodiments, MOO2CI2 may be used to deposit a conformal layer. The deposition may be a PEALD deposition using MOO2CI2. Above about 400°C, thermal ALD may be used to deposit a conformal layer using MOO2CI2. In some embodiments, M0CI5 may be used with a PEALD to deposit the conformal layer. Figure 6A shows the structure afterthe fill, including a thin MoP layer on the left and, on the right, an embodiment in which MoP fills most of the feature prior to conformal Mo deposition. Non-selective deposition can be used to deposit on the field region. While Mo is shown in Figure 6A, the non-selective deposition may also be another metal or MoP.

[0096] Figure 6B shows an example of another process in which a thin MoP layer is deposited on a Cu layer. This process involves selective ALD of MoP on Cu, followed by selective deposition of Mo as described further below. Figure 6C shows an example of a process in which a thin layer of MoP is selectively deposited on Cu and TaN and not on surrounding low-k.

[0097] In some embodiments, the MoP layer may be used as thin protective layer and / or a main conductor. For example, when depositing Mo or other conductor on copper, a thin MoP layer be formed as a protective layer. Example thicknesses of the protective layer can be less than 30 Angstroms, or between 10 and 20 Angstroms. As described elsewhere, thin MoP layers can be molybdenum-rich. MoP is more resistant than molybdenum to further exposure to chlorine-containing reactants. For example, during deposition of molybdenum using a chlorine-containing molybdenum precursor, an MoP layer can prevent chlorine species from attacking the copper or other underlying material. Examples of other materials that MoP can be deposited on and protect include metal silicides and titanium-containing films such as TiN, TiAIC, and TiC. In addition to its barrier properties, MoP is useful as a protective layer as it can be deposited at lower temperatures and / or with a higher deposition rate than Mo. Damage during the deposition is reduced. Figure 6D is plot comparing growth rate of MoP and Mo using M0CI5 as the molybdenum precursor.Molybdenum and Molybdenum Phosphide Deposition

[0098] As described above, in some embodiments, an elemental Mo film is deposited on the MoP films described herein. Deposition of molybdenum as described herein involves reacting a Mo-containing precursor, also referred to as a molybdenum (Mo) precursor. The same or different Mo precursor may be used for MoP and Mo films. In some embodiments, a molybdenum halide compound as described above is used. In methods including surface treatment using a molybdenum halide compound, the same or different compound may be usedAttorney Docket No. LAM1P147WO-12345-1WO for deposition.

[0099] In some embodiments, a Mo precursor is a molybdenum chloride (MoClx) compound also referred to as a molybdenum chloride precursor or MoClxprecursor. Molybdenum chloride precursors are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (M0CI2), molybdenum trichloride (M0CI3), molybdenum tetrachloride (M0CI4), molybdenum pentachloride (M0CI5), and molybdenum hexachloride (MoCk). In some embodiments, M0CI5 or MoCkare used. While the description chiefly refers to MoClxprecursors, in other embodiments, other molybdenum halide precursors may be used. Molybdenum halide precursors are given by the formula MoXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. Examples of MoXzprecursors include molybdenum fluoride (MoFe). In some embodiments, a non-fluorine-containing MoXzprecursor is used to prevent fluorine etch or incorporation. In some embodiments, a non-bromine-containing and / or a non-iodine-containing MoXzprecursor is used to prevent etch or bromine or iodine incorporation.

[0100] In some embodiments, the feature may be filled using a molybdenum oxyhalide precursor. Molybdenum oxyhalide precursors are given by the formula MoOyXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)), and y and z are numbers greater than 0 such that MoOyXzforms a stable compound. Examples of molybdenum oxyhalides include molybdenum dichloride dioxide (MOO2CI2), molybdenum tetrachloride oxide (MoOCU), molybdenum tetrafluoride oxide (M0OF4), molybdenum dibromide dioxide (MoC^Br?), and the molybdenum iodides MOO2I, and MO4O11I. It should be understood that as used herein the term molybdenum oxyhalide precursor may refer to a molybdenum oxyhalide precursor as described above or a molybdenum-containing oxyhalide precursor that includes molybdenum, oxygen, a halide and one or more other elements. In some embodiments, molybdenum oxyhalide or molybdenum-containing oxyhalides may include multiple different halogens (e.g., F and Cl and / or I and / or Br, etc.). A feature may be filled with molybdenum using a MoXxprecursor, MoOyXzprecursor, or a combination thereof.

[0101] For deposition of molybdenum into the feature, the molybdenum precursor may be reacted with a co-reactant. Examples of co-reactants include hydrogen (H2), silane (SiFU), diborane (B2H6), germane (Gel-14), ammonia (NH3), and hydrazine (N2H4). Ammonia and hydrazine may be used to deposit molybdenum nitrides or molybdenum oxynitrides. As described above, phosphine (with or without H2) may be used to deposit MoP.

[0102] In some embodiments, deposition of molybdenum may use a plasma-based process.Attorney Docket No. LAM1P147WO-12345-1WO Gas may be fed into a remote or in-situ plasma generator to generate plasma species. Examples of gas that may be used to generate plasma may be a hydrogen-containing gas, such as H2, nitrogen-containing gas, such as nitrogen (N2) and other gases, such as Ar and NH3. The plasma species may be inert or react with the molybdenum precursor to form a film.

[0103] A feature may be filled with molybdenum by atomic layer deposition (ALD) or chemical vapor deposition (CVD). Thermal ALD or plasma enhanced ALD (PEALD) may be used. Similarly, thermal CVD or plasma enhanced CVD (PECVD) may be used.

[0104] ALD is a surface-mediated deposition technique in which doses of a precursor and a reactant are sequentially introduced into a deposition chamber. One or more cycles of sequential doses of a molybdenum precursor and reactant may be used to deposit Mo. For example, in the deposition of a molybdenum layer on MoP, M0CI5 may be used as a precursor and H2as a reducing agent. Doses of MoCLand H2are sequentially introduced into the deposition chamber with a purge gas, such as argon, flowed between. For ALD, the temperature of the substrate and the pressure of the chamber may be controlled. For example, the substrate may be heated between 200°C and 800°C, e.g., between 250°C and 550°C or between 300°C and 500°C between 350°C and 450°C. In some embodiments, the chamber may be pressurized between 10 Torr and 200 Torr, e.g., between 50 Torr and 90 Torr. In some embodiments, the temperature and / or pressure may be used to control the rate of reactions. In some embodiments, the temperature and / or pressure may be used to control selectivity.

[0105] In some embodiments, the Mo precursor is a molybdenum fluoride (MoFx) compound, also referred to as a molybdenum fluoride precursor or MoFxprecursor. Molybdenum chloride precursors are given by the formula MoFx, where x is 4, 5, or 6, and include molybdenum tetrafluoride (M0F4), molybdenum pentafluoride (M0F5), and molybdenum hexafluoride (MoFe).

[0106] MoFe can be advantageous as it has a boiling point of 34°C. Being a gas at standard pressure and 35°C allows MoFe to be delivered through a mass flow controller (MFC) at room temperature, without heating and without condensing and forming particles. However MoFe is an aggressive etchant and exposure to MoFe during a process can result in etching instead of or in addition to Mo deposition. In some embodiments, deposition using MoFe involves providing a flow of MoFe in a process gas with the MoFe at a molar concentration of 0.01% or less. Concentration may be significantly lower in some embodiments, for example, 0.008% or less, 0.005% or less, or 0.004% or less. These values can also be expressed as parts per million (ppm) of a gas: 100 ppm (100 MoFe molecules per 1 million gas particles (atoms, molecules)) or less, 80 ppm or less, or 40 ppm or less. At temperatures between 200°C and 650°C, for example, a molarAttorney Docket No. LAM1P147WO-12345-1WO concentration at or below 0.004% results in CVD deposition when flowed with H2 and argon. Higher temperatures may be used to favor the deposition reaction and allow higher concentrations of MoFg, e.g., up to 0.01%. In some embodiments, concentrations may be 0.0039% or .0035% or less. In some embodiments, the MoFg concentration is at least 0.00004% or at least 0.0001%. Concentration may be very low with an exposed metal surface to grow on, for example.

[0107] Deposition using MoFe with H2 as reducing agent occurs only at unusually low concentration. As an example, for 0.5 seem of MoF6, a total flow rate of 13,500 seem may be used, for a MoFe concentration of 0.0037%. Deposition using metal halides and hydrogen generally involves much higher concentrations. For example, deposition of molybdenum using molybdenum hexachloride and hydrogen can be performed using concentrations 5 to 10 times higher than those used for MoFg.

[0108] In some embodiments, MoFg may be used at higher concentrations and lower temperatures with a reducing agent that is stronger than that of hydrogen. Lower temperatures can reduce or prevent etching with MoFg; however, at low temperatures H2 may not result in deposition. Stronger reducing agents such silane, disilane, polysilanes and diborane may be used for deposition at lower temperatures (e.g., below 200°C). The resulting films may not be pure molybdenum and in some cases are more resistive than those deposited using H2 as the reducing agent. For these reasons they may not be appropriate for some applications.

[0109] In some embodiments, molybdenum fill may involve CVD. In a CVD process, the molybdenum precursor and reactant are in vapor phase together in the deposition chamber. Generally speaking, a CVD process fills a feature faster than an ALD process. In one example, the precursor may be a molybdenum oxychloride, such as MOO2CI2, and is flowed into the chamber with a reactant, such as H2. In this example, the wafer is simultaneously exposed to the precursor and reactant, which react and fill features with Mo. In one example, MoFg is flowed into the chamber with a reactant, such as H2. In this example, the wafer is simultaneously exposed to the precursor and reactant, which react and fill features with Mo.

[0110] In still some other embodiments, a feature may be filled using a pulsed CVD process. The pulsed CVD process continuously flows a reactant into a chamber while pulses of a precursor flow into the chamber. For example, H2 gas may be flowed into the chamber and is continuously flowing into the chamber while the molybdenum-containing precursor is intermittently flowing into the chamber. The temperature of the substrate and pressure in the chamber may be controlled during a CVD operation.Attorney Docket No. LAM1P147WO-12345-1WO

[0111] Plasma-enhanced CVD may be used in which a plasma is ignited during the deposition. In a pulsed CVD process, a plasma may be ignited during deposition cycle or during, e.g., pulses of the hydrogen reactant. In some embodiments, a remote plasma may be used. The plasma may be remotely-generated or direct. Further it may be generated by any appropriate plasma generator including a capacitively-coupled plasma generator or an inductively-coupled plasma generators. A microwave plasma generator may be used.

[0112] In addition to the molybdenum halides and molybdenum oxyhalides described herein, the molybdenum films may be deposited using organometallic and / or sulfur-containing precursors. Organometallic molybdenum-containing compounds and / or sulfur-containing molybdenum-containing compounds may be used as molybdenum precursors in some embodiments. Examples of these are given in PCT publication W02023250500, incorporated by reference herein.

[0113] For deposition into complex features, molybdenum oxyhalides as described above may be used. These precursors are able to diffuse through complex features without etching at the feature tops. Use of precursors that have higher etching capability (e.g., M0CI5) may etch at locations in the structure that have a higher concentration of precursor.

[0114] Deposition of MoP films by ALD is described above with respect to Figures 4A and 4B. CVD (including plasma-enhanced CVD) and pulsed CVD processes may be used. Examples of molybdenum precursors are given above. For deposition in complex structures or for non-selective deposition, molybdenum oxyhalides may be used. As described further below, for selective deposition, a molybdenum halide may be used.

[0115] One example of a phosphorus source is phosphine (PH3). PH3 is highly reactive, enabling the formation of a MoP film on oxide with a small amount of a PH3. In one example, 10% PH3 in N2, He, or other inert gas is used. The concentration can be used to control the amount of phosphorus in the MoP film. Concentration of PH3 can be increased to increase film continuity and / or decrease roughness. PH3 concentration at the dose operation may be between 0.001 and 5%. In addition to phosphine, other P-containing compounds may be used, including but not limited to P(CH3)3, P(C2H5)3, PCI3, and POCI3.Selective deposition

[0116] Molybdenum may be selectively deposited into a feature using the methods described herein. Selective deposition refers to preferential deposition on a first material with respect to a second material. Molybdenum deposition and growth may be easier on a metal materialAttorney Docket No. LAM1P147WO-12345-1WO relative to molybdenum deposition and growth on a dielectric material. For example, a feature may have a sidewall surface of SiO2and a MoP plug in a bottom portion of the feature. In selective deposition, molybdenum is deposited into the feature and may grow on the MoP plug but not grow (or grow to a lesser extent) on the SiO2sidewall surfaces.

[0117] P rocess conditions such as the precursor gas, the reducing agent, process temperature, process pressure, and exposure time may affect the selectivity of the molybdenum film being deposited. Process temperatures for selective deposition of the molybdenum film may be between 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. At these temperatures, the molybdenum film is selectively deposited on conductive metal or metal compound surfaces, such as a MoP orTiN surface, in a feature relative to dielectric surfaces.

[0118] Different precursor gases may have different process windows in which molybdenum film may be selectively deposited. Generally speaking, MoCIs gas has a large process window, i.e., large temperature and pressure range, where the precursor gas retains its selectivity. For example, MoCIs may be selectively deposited on a metal material with respect to a dielectric material where the process temperature is 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. Generally speaking, higher process temperatures and higher process pressures reduce the selectivity of the deposited gas. MoCIs deposits selectively on metals, titanium nitride (TiN) and other conductive materials relative to dielectric materials at a wide range of temperatures.

[0119] MoCIs may be reacted with different reactants to deposit a molybdenum or molybdenum-containing film. Phosphine, for example, may be used to deposit MoP layers and H2may be used to deposit elemental Mo layers.

[0120] Described below are examples of deposition of molybdenum-containing film within a feature using a M0CI5 precursor and different process controls. In a first example, the M0CI5 precursor is reacted with a hydrogen (H2) reactant using the deposition methods described above. In the description herein, the metal precursors are reacted with H2as a co-reactant (also referred to as a hydrogen reactant or H2reactant). Other reactants may be used instead of hydrogen including other hydrogen-containing reactants such SiFU, B2He, NH3, as appropriate. Reactants such as B2HG and / or SiFU are stronger reducing agents and generally show reduced selectivity. They can also result in higher resistivity. Thus, in some embodiments, using H2as described herein is advantageous. As noted above, process temperatures for selective deposition of the molybdenum film from M0CI5 may be between 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. At these temperatures, the molybdenum film is selectively depositedAttorney Docket No. LAM1P147WO-12345-1WO on conductive metal or metal compound surfaces, such as a TIN surface, in a feature relative to dielectric surfaces. The molybdenum film grows from the locations where the conductive surfaces are located in a feature. If the conductive surface is a TiN plug at the bottom of the feature, the molybdenum film may be deposited and grown from the bottom of the feature. In a second example, the molybdenum film may be deposited usingthe MoCIs precursor and the H2 reactant, but at higher temperatures, i.e., above 800°C. This process window may have the molybdenum film deposited on both the dielectric and conductive surfaces within the feature. The deposition of the molybdenum film on the dielectric surface may be used to create a barrierless molybdenum layer in the feature.

[0121] In some embodiments, selective deposition is performed using a MoFxprecursor. Molybdenum fluoride precursors are given by the formula MoFxas described above. As indicated above, MoFg can be advantageous for ease of delivery. Deposition of molybdenum from MoFg at the low concentrations disclosed above results in high (at least 100:1) selectivity of one elemental metal surfaces (e.g., W, Mo, Cu) relative to oxides and nitrides such as silicon oxide and titanium nitride. MoFg also deposits selectively on metals with respect to dielectric materials, though is less selective than M0CI5. An example of selectivity of MoFg is shown in Figure 7. As can be seen, after a delay, MoFg deposits on thermal oxide. Selectivity of molybdenum halides can also be affected by operating at conditions (e.g., concentration, temperature, etc.) at which the molybdenum halide also etches.

[0122] Selective deposition using a molybdenum oxyhalide precursor is much more difficult than using a molybdenum halide precursor. However, the surface treatments described above significantly improve selectivity of Mo deposition from MOO2CI2. As indicated above, examples of MoOyXz precursors include MOO2CI2, M00CI4, M00F4, MoO2Br2, MOO2I, and MO4O11I. The feature may be filled using ALD, plasma enhanced ALD, chemical vapor deposition (CVD), or plasma enhanced CVD. For ALD or CVD, H2 may be the reducing agent. Molybdenum deposits more quickly using a molybdenum oxyhalide precursor than the MoClxprecursor used in the surface treatment. For example, a MoOyXzprecursor may deposit molybdenum at a deposition rate at least twice as fast as a MoClxprecursor for a non-plasma process.Non-selective Deposition

[0123] The selectivity described above may be reduced or eliminated using plasma deposition in some embodiments, such that the molybdenum is deposited on different materials. This may be referred to as non-selective deposition. When ALD processes are used, the non-selectiveAttorney Docket No. LAM1P147WO-12345-1WO deposition may be conformal to the contours of surface. The plasma is generally an in-situ or direct plasma for non-selective deposition.

[0124] Examples of plasma processes include plasma-enhanced ALD (PEALD) or plasma enhanced CVD (PECVD) processes using a molybdenum halide precursor. In some embodiments, the molybdenum halide precursor is M0CI5 or MoFg. A molybdenum oxyhalide may also be used, with examples including M0O2CI2 or M0OCI4. Hydrogen (H2) or other reducing agent may be used for the PEALD or PECVD deposition.

[0125] For PECVD deposition, the molybdenum precursor can be co-flowed with the reducing agent. For MoFg, the concentration of the MoFe is as described above, with the mixture flowed into a plasma generator. Remote or direct plasmas may be used. In some embodiments, a capacitively-coupled direct plasma that is generated in the chamber is employed.

[0126] Non-selective deposition may also be a thermal process using molybdenum oxyhalides. For example, thermal MOO2CI2 and H2 may be used to deposit a molybdenum layer non-selectively. Temperatures at or above 450°C may be used in for thermal deposition from M0O2CI2 and H2.

[0127] To reduce selectivity, an ALD process may be performed to deposit a Mo-containing nucleation layer. For nucleation layer deposition, a stronger reducing agent than hydrogen is employed. This can allow the film to grow on surfaces that face nucleation delay with hydrogen as reducing agent. As described further below, such a reducing agent can be a silicon-containing or boron-containing reducing agent such as silane (SiH4) or diborane (B2H6). Germanium-containing reducing agents (e.g., GeH4) may be used. These may be used to deposit an elemental molybdenum film. In other embodiments, a reducing agent such as ammonia (NH3) may be used. In such cases, the molybdenum layer may be a molybdenum nitride or molybdenum oxynitride layer, depending on the presence of oxygen in the molybdenum precursor. This oxynitride layer or nitride layer may be converted into an elemental molybdenum layer in the subsequent process.

[0128] When using MoFe, the concentration of MoFe in the MoFe dose may as described above, i.e., 0.01% or less, 0.008% or less, 0.005% or less, or 0.004% or less of the total gas flowed into the chamber. Alternatively, because a stronger reducing agent than hydrogen is used in the subsequent operation, a higher concentration (e.g., up to 0.1% molar) may be used during the MoFe. Some amount of a reducing agent may be present to suppress etching. As described above, this can be between 0.5% and 10% or between 1% and 9% H2. Another reducing agent may be included instead of or in addition to hydrogen. The balance is wholly or predominatelyAttorney Docket No. LAM1P147WO-12345-1WO argon or other inert gas. During the reducing agent dose, the dose is wholly or predominately the reducing agent, with some amount (e.g., up to 10%, or between 1% and 9%) being argon in some embodiments, and the remainder the reducing agent. After deposition of the nucleation layer, a bulk molybdenum layer can be deposited using H2 as a reducing agent by any of the methods described above, including thermal or plasma-enhanced ALD or CVD.Nucleation Layer

[0129] In some embodiments, filling a feature can involve depositing a nucleation layer. A nucleation layer is a thin layerthat supports bulk deposition. It may be conformal to the feature. In many embodiments, a nucleation layer is deposited by an ALD process. In some embodiments, a Mo nucleation layer is deposited using one or more of a boron-containing reducing agent (e.g., BzHe) or a silicon-containing reducing agent (e.g., SiF ) as a co-reactant. For example, one or more S / Mo cycles or Mo / S cycles may be used to deposit a Mo nucleation layer. In another example, one or more B / Mo cycles or Mo / B cycles may be used to deposit a Mo nucleation layer on which a bulk Mo layer is deposited. B refers to a pulse of diborane or other boron-containing reducing agent and S to a pulse of silane or other silicon-containing reducing agent, such that S / Mo refers to a pulse of silane followed by a pulse of a Mo-containing precursor. B / Mo and S / Mo cycles (or Mo / B and / or Mo / S) may both be used to deposit a Mo nucleation layer, e.g., x(B / Mo) + y(S / Mo), with x and y being integers. Examples of boron-containing reactants include diborane (BzHe), alkyl boranes, alkyl boron, aminoboranes (CHshNBfCHzh, carboranes such as C2BnHn+2, and other boranes. Examples of boranes include BnHn+4, BnHn+6, BnHn+8, BnHm, where n is an integer from 1 to 10, and m is a different integer than m. Examples of silicon-containing reducing agents including silane (SiH4) and other silanes such as disilane (Si2He).

[0130] In some embodiments, deposition of a Mo nucleation layer may involve using a non-oxygen-containing precursor, e.g., molybdenum hexafluoride (MoFg) or molybdenum pentachloride (M0CI5). Oxygen in oxygen-containing precursors may react with a silicon- or boron-containing reducing agent to form MoSixOyor MoBxOy, which are impure, high resistivity films. In some embodiments, oxygen-containing precursors may be used for nucleation layer deposition with oxygen incorporation minimized. Oxygen incorporation can be minimized by high reducing agent flows (e.g., greater than 100:1 volumetric flow rate of reducing agent to oxygen-containing Mo precursor).

[0131] In some embodiments, H2may be used as a reducing gas for Mo nucleation layer deposition instead of a boron-containing or silicon-containing reducing gas. Example thicknessesAttorney Docket No. LAM1P147WO-12345-1WO for deposition of a Mo nucleation layer range from 5 A to 30 A. Films at the lower end of this range may not be continuous; however, as long as they can help initiate continuous bulk Mo growth, the thickness may be sufficient.

[0132] In some embodiments, the reducing agent pulses during deposition of a nucleation or bulk Mo layer may be done at lower substrate temperatures than the Mo precursor pulses. For example, or B2H6 or a SiHU (or other boron- or silicon-containing reducing agent) pulse may be performed at a temperature below 300°C, with the Mo pulse at temperatures greaterthan 300°C.

[0133] In some embodiments, the reducing agent is NH3or other nitrogen-containing reducing agents such as hydrazine (N2H4). NH3 chemisorption on dielectrics is more favorable than that of H2. In some embodiments, the reducing agent and precursor are selected such that they react without reducing agent dissociation. NH3 reacts with metal oxychlorides and metal chlorides without dissociation. This is in contrast to, for example, ALD from metal oxychlorides that use H2 as a reducing agent; H2 dissociates on the surface to form adsorbed atomic hydrogen, which results in very low concentrations of reactive species and low surface coverage during initial nucleation of metal on the dielectric surface. By using NH3and metal oxychloride or metal chloride precursors, nucleation delay is reduced or eliminated at deposition temperatures up to hundreds of degrees lower than used by H2 reduction of the same metal precursors.

[0134] In some embodiments, the reducing agent may be a boron-containing or silicon-containing reducing agent such as B2H6 or SiF . These reducing agents may be used with metal chloride precursors, with metal oxychlorides; however, the B2H6 and SiF may react with water formed as a byproduct during the ALD process and form solid B2O3and SiCh. These are insulating and can remain in the film, increasing resistivity. Use of NH3 also has improved adhesion over B2H6 and SiF ALD processes on certain surfaces including AI2O3. The resulting nucleation layer is generally not a pure elemental film but a metal nitride or metal oxynitride film. In some embodiments, there may be residual chlorine or fluorine from the deposition, particularly if the deposition is performed at low temperatures. In some embodiments, there may be no more than a trace amount of residual chlorine or fluorine. In some embodiments, the nucleation layer is an amorphous layer. Impurities in the film (e.g., oxygen, NH3, chlorine, or other halogens) facilitate the growth of an amorphous microstructure. In some embodiments, the nucleation layer as deposited is an amorphous molybdenum oxynitride layer or an amorphous molybdenum nitride layer. The amorphous character templates large grain growth in the subsequently deposited conductor. The surface energy of nitride or oxynitride relative to an oxide surface is much more favorable than that of a metal on an oxide surface, facilitating formation of aAttorney Docket No. LAM1P147WO-12345-1WO continuous and smooth film on the dielectric. This allows formation of thin, continuous layers. Example thicknesses of the nucleation layer range from 5-30A as deposited. Depending on the temperature, this may be about 5-50 ALD cycles, for example.Apparatus

[0135] Figure 8 depicts a schematic illustration of an embodiment of an ALD process station 800 having a process chamber 802 for maintaining a low-pressure environment. In some embodiments, a plurality of ALD process stations may be included in a common low-pressure process tool environment. For example, Figures9Aand 9B depict embodiments of a multi-station processing tool. In some embodiments, one or more hardware parameters of ALD process station 800, including those discussed in detail below, may be adjusted programmatically by one or more computer controllers 850. In some other embodiments, a process chamber may be a single station chamber.

[0136] ALD process station 800 fluidly communicates with reactant delivery system 801a for delivering process gases to a distribution showerhead 806. Reactant delivery system 801a includes a mixing vessel 804 for blending and / or conditioning process gases, such as a Mo precursor-containing gas, a hydrogen-containing gas, an argon or other carrier gas, or other reactant-containing gas, for delivery to showerhead 806. One or more mixing vessel inlet valves 820 may control introduction of process gases to mixing vessel 804. In various embodiments, deposition of an initial Mo layer is performed in process station 800 and in some embodiments, other operations such as in-situ clean or Mo gap fill may be performed in the same or another station of the multi-station processing tool as further described below with respect to Figure 9A.

[0137] As an example, the embodiment of Figure 8 includes a vaporization point 803 for vaporizing liquid reactant to be supplied to the mixing vessel 804. In some embodiments, vaporization point 803 may be a heated vaporizer. In some embodiments, a liquid precursor or liquid reactant may be vaporized at a liquid injector (not shown). For example, a liquid injector may inject pulses of a liquid reactant into a carrier gas stream upstream of the mixing vessel 804. In one embodiment, a liquid injector may vaporize the reactant by flashing the liquid from a higher pressure to a lower pressure. In another example, a liquid injector may atomize the liquid into dispersed microdroplets that are subsequently vaporized in a heated delivery pipe. Smaller droplets may vaporize faster than larger droplets, reducing a delay between liquid injection and complete vaporization. Faster vaporization may reduce a length of piping downstream from vaporization point 803. In one scenario, a liquid injector may be mounted directly to mixingAttorney Docket No. LAM1P147WO-12345-1WO vessel 804. In another scenario, a liquid injector may be mounted directly to showerhead 806.

[0138] Reactant delivery system 801a may also include one or more solid precursor delivery components including one or more on-board ampoules 813 and / or bulk delivery components 815. Figure 10 below provides an example of a bulk delivery system.

[0139] In some embodiments, a liquid flow controller (LFC) upstream of vaporization point 803 may be provided for controlling a mass flow of liquid for vaporization and delivery to process chamber 802. For example, the LFC may include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC may then be adjusted responsive to feedback control signals provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take one second or more to stabilize liquid flow using feedback control. This may extend a time for dosing a liquid reactant. Thus, in some embodiments, the LFC may be dynamically switched between a feedback control mode and a direct control mode. In some embodiments, this may be performed by disabling a sense tube of the LFC and the PID controller.

[0140] Showerhead 806 distributes process gases toward substrate 812. In the embodiment shown in Figure 8, the substrate 812 is located beneath showerhead 806 and is shown resting on a pedestal 808. Showerhead 806 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to substrate 812.

[0141] In some embodiments, pedestal 808 may be raised or lowered to expose substrate 812 to a volume between the substrate 812 and the showerhead 806. In some embodiments, pedestal 808 may be temperature controlled via heater 810. Pedestal 808 may be set to any suitable temperature, such as between about 250°C and about 800°C during operations for performing various disclosed embodiments. It will be appreciated that, in some embodiments, pedestal height may be adjusted programmatically by a suitable computer controller 850. At the conclusion of a process phase, pedestal 808 may be lowered during another substrate transfer phase to allow removal of substrate 812 from pedestal 808.

[0142] In some embodiments, a position of showerhead 806 may be adjusted relative to pedestal 808 to vary a volume between the substrate 812 and the showerhead 806. Further, it will be appreciated that a vertical position of pedestal 808 and / or showerhead 806 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, pedestal 808 may include a rotational axis for rotating an orientation of substrate 812. It will be appreciated that, in some embodiments, one or more of these example adjustments may be performed programmatically by one or more suitable computer controllers 850. The computerAttorney Docket No. LAM1P147WO-12345-1WO controller 850 may include any of the features described below with respect to controller 850 of Figure 8.

[0143] In some embodiments where plasma may be used as discussed above, showerhead 806 and pedestal 808 electrically communicate with a radio frequency (RF) power supply 814 and matching network 816 for powering a plasma. In some embodiments, the plasma energy may be controlled by controlling one or more of a process station pressure, a gas concentration, an RF source power, an RF source frequency, and a plasma power pulse timing. For example, RF power supply 814 and matching network 816 may be operated at any suitable power to form a plasma having a desired composition of radical species. Likewise, RF power supply 814 may provide RF power of any suitable frequency. In some embodiments, RF power supply 814 may be configured to control high- and low-frequency RF power sources independently of one another. Example low-frequency RF frequencies may include, but are not limited to, frequencies between 0 kHz and 900 kHz. Example high-frequency RF frequencies may include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz, or greater than about 13.56 MHz, or greater than 27 MHz, or greater than 80 MHz, or greater than 60 MHz. It will be appreciated that any suitable parameters may be modulated discretely or continuously to provide plasma energy for the surface reactions.

[0144] In some embodiments, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, plasma density and / or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for providing programmatic control of plasma power. It will be appreciated that, in some embodiments, other monitors may be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0145] In some embodiments, instructions for a controller 850 may be provided via input / output control (IOC) sequencing instructions. In one example, the instructions for setting conditions for a process phase may be included in a corresponding recipe phase of a process recipe. In some cases, process recipe phases may be sequentially arranged, so that all instructions for a process phase are executed concurrently with that process phase. In some embodiments, instructions for setting one or more reactor parameters may be included in aAttorney Docket No. LAM1P147WO-12345-1WO recipe phase. For example, a first recipe phase may include instructions for setting a flow rate of an inert and / or a reactant gas (e.g., a Mo precursor), instructions for setting a flow rate of a carrier gas (such as argon), and time delay instructions for the first recipe phase. A second, subsequent recipe phase may include instructions for modulating or stopping a flow rate of an inert and / or a reactant gas, and instructions for modulating a flow rate of a carrier or purge gas and time delay instructions for the second recipe phase. A third recipe phase may include instructions for modulating a flow rate of a second reactant gas such as H2, instructions for modulating the flow rate of a carrier or purge gas, instructions for igniting a plasma, and time delay instructions for the third recipe phase. A fourth, subsequent recipe phase may include instructions for modulating or stopping a flow rate of an inert and / or a reactant gas, and instructions for modulating a flow rate of a carrier or purge gas and time delay instructions for the fourth recipe phase. It will be appreciated that these recipe phases may be further subdivided and / or iterated in any suitable way within the scope of the present disclosure.

[0146] Further, in some embodiments, pressure control for process station 800 may be provided by butterfly valve 818. As shown in the embodiment of Figure 8, butterfly valve 818 throttles a vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of process station 800 may also be adjusted by varying a flow rate of one or more gases introduced to the process station 800.

[0147] Figure 9A and Figure 9B show examples of processing systems. Figure 9A shows an example of a processing system including multiple chambers. The system 900 includes a transfer module 903. The transfer module 903 provides a clean, vacuum environment to minimize risk of contamination of substrates being processed as they are moved between various modules. Mounted on the transfer module 903 is a multi-station chamber 909 capable of performing in-situ clean and / or ALD processes described above. Surface treatment and / or initial Mo layer deposition may be performed in the same or different station or chamber as the subsequent Mo gap fill.

[0148] Chamber 909 may include multiple stations 911, 913, 915, and 917 that may sequentially perform operations in accordance with disclosed embodiments. For example, chamber 909 may be configured such that station 911 performs an in-situ treatment using a MoCL precursor. Station 913 may be configured to selectively treat the field region and upper sidewalls and stations 915 and 917 may be configured to perform ALD of bulk Mo using an molybdenum oxyhalide precursor and H2. In another example, chamber 909 may be configured such that station 911 performs in-situ clean, station 913 performs ALD of an initial Mo layer,Attorney Docket No. LAM1P147WO-12345-1WO station 913 selectively treats the layer, and 914 deposition of bulk Mo. In another example, the chamber 909 may be configured to do parallel processing of substrates, with each station performing multiple processes sequentially.

[0149] Two or more stations may be included in a multi-station chamber, e.g., 2-6, with the operations appropriately distributed. For example, a two-station chamber may be configured to perform ALD of an initial Mo layer in a first station followed by ALD of bulk Mo in a second station. Stations may include a heated pedestal or substrate support, one or more gas inlets or showerhead or dispersion plate.

[0150] Also mounted on the transfer module 903 may be one or more single or multi-station modules 907. In some embodiments, a preclean as described above may be performed in a module 907, after which the substrate is transferred under vacuum to another module (e.g., another module 907 or chamber 909) for ALD. In another example, a module for selective treatment of a film may be mounted on the transfer module. An example is shown in Figure 10.

[0151] The system 900 also includes one or more wafer source modules 901, where wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 919 may first remove wafers from the source modules 901 to loadlocks 921. A wafer transfer device (generally a robot arm unit) in the transfer module 903 moves the wafers from loadlocks 921 to and among the modules mounted on the transfer module 903.

[0152] Chamber 709 may have one or more of the following features to enable single chamber metallization processes:Individually addressable plasma power generators associated with each station;Individually addressable reactant inputs associated with each station;Multi-plenum showerheads on each station;Dual solid precursor delivery systems.

[0153] Solid precursor delivery systems may include bulk delivery systems and / or on-board ampoules. Figure 10 below provides an examples of a solid precursor delivery system that may be employed.

[0154] Figure 9B is an embodiment of a system 900. The system 900 in Figure 9B has wafer source modules 901, a transfer module 903, atmospheric transfer chamber 919, and loadlocks 921, as described above with reference to Figure 9A. The system in Figure 9B has three single station modules 957a-975c. The system 900 may be configured to sequentially perform operations in accordance with disclosed embodiments. For example, the single station modulesAttorney Docket No. LAM1P147WO-12345-1WO 957a-957c may be configured so that a first module 957a performs a surface treatment, a second module 957b performs ALD of an initial Mo layer using a molybdenum halide precursor, and a third module 957c performs ALD of bulk Mo using a molybdenum oxyhalide precursor. In this example, an in-situ clean may be optionally performed in second module 957b instead of or in addition to a preclean in first module 957a. In another example, the single station modules 957a-957c may be configured so that a first module 957a performs a deposition of an initial metal layer, a second module 957b performs selective treatment, and a third module 957c performs ALD of bulk Mo using a molybdenum oxyhalide precursor. In yet another example, one module may be configured for deposition, another module for selective treatment, and another module for etch.

[0155] With respect to molybdenum phosphide deposition, the system 900 can be configured in various manners. In one example, a module 907 may be a batch reactor used for MoP deposition as described above, with multi-station chamber 909 used for bulk molybdenum (Mo) deposition. In some embodiments, each station is sequentially used to deposit the bulk Mo. In other embodiments, a first station 911 may be used for MoP deposition with the stations 913-917 used for bulk Mo deposition. Still further, in some embodiments, each of stations 913-917 is used to deposit both MoP and Mo in parallel on different substrates.

[0156] Stations may include a heated pedestal or substrate support, one or more gas inlets or showerhead or dispersion plate as described above with reference to Figure 8.

[0157] Returning to Figure 9A and 9B, in various embodiments, a system controller 929 is employed to control process conditions during deposition. The controller 929 will typically include one or more memory devices and one or more processors. A processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc. Such a system controller may be employed in control of any of the processes and apparatus described herein.

[0158] The controller 929 may control all the activities of the apparatus. The system controller 929 executes system control software, including sets of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored on memory devices associated with the controller 929 may be employed in some embodiments.

[0159] Typically, there will be a user interface associated with the controller 929. The user interface may include a display screen, graphical software displays of the apparatus and / orAttorney Docket No. LAM1P147WO-12345-1WO process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0160] System control logic may be configured in any suitable way. In general, the logic can be designed or configured in hardware and / or software. The instructions for controlling the drive circuitry may be hard coded or provided as software. The instructions may be provided by "programming." Such programming is understood to include logic of any form, including hard coded logic in digital signal processors, application-specific integrated circuits, and other devices which have specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general-purpose processor. System control software may be coded in any suitable computer readable programming language.

[0161] The computer program code for controlling the Mo precursor pulses, hydrogen pulses, and argon flow, and other processes in a process sequence can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran, or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program. Also as indicated, the program code may be hard coded.

[0162] The controller parameters relate to process conditions, such as, for example, process gas composition and flow rates, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of a recipe and may be entered utilizing the user interface.

[0163] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 929. The signals for controlling the process are output on the analog and digital output connections of the deposition apparatus.

[0164] The system software may be designed or configured in many ways. For example, various chamber component subroutines or control objects may be written to control operation of the chamber components necessary to carry out the deposition processes in accordance with the disclosed embodiments. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0165] In some implementations, a controller 929 is part of a system, which may be part of the above-described examples. Such systems can include semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and / or specific processing components (a wafer pedestal, a gas flow system, etc.). These systemsAttorney Docket No. LAM1P147WO-12345-1WO may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the "controller," which may control various components or subparts of the system or systems. The controller 929, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.

[0166] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0167] The controller 929, in some implementations, may be a partof or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller 929 may be in the "cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which areAttorney Docket No. LAM1P147WO-12345-1WO then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. The parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0168] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a PVD chamber or module, a CVD chamber or module, an ALD chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0169] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0170] The controller 929 may include various programs. A substrate positioning program may include program code for controlling chamber components that are used to load the substrate onto a pedestal or chuck and to control the spacing between the substrate and other parts of the chamber such as a gas inlet. A substrate tilt and rotation program may include for tilt and rotation. A process gas control program may include code for controlling gas composition, flow rates, pulse times, and optionally for flowing gas into the chamber prior to deposition in order to stabilize the pressure in the chamber. A pressure control program may include code for controlling the pressure in the chamber by regulating, e.g., a throttle valve in the exhaust system of the chamber. A heater control program may include code for controlling the current to a heating unit that is used to heat the substrate. Alternatively, the heater control program mayAttorney Docket No. LAM1P147WO-12345-1WO control delivery of a heat transfer gas such as helium to the wafer chuck.

[0171] Examples of chamber sensors that may be monitored during deposition include mass flow controllers, pressure sensors such as manometers, and thermocouples located in the pedestal orchuck. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain desired process conditions.

[0172] Figure 10 depicts an example precursor delivery system according to various implementations. The precursor delivery system 1000, which may also be referred to herein as the system 1000, includes an ampoule 1002 that is configured to have a precursor 1004 (shown with cross-hatching) and heat that precursor 1004 to vaporize it and create a precursor vapor in the headspace 1006 of the ampoule 1002. The ampoule includes an inlet 1008 and an outlet 1010. The inlet 1008 is configured to receive inert gas from an inert gas source 1012. The inert gas and precursor vapor in the headspace of the ampoule form a mixture that is flowed out of the outlet 1010. In some implementations, like in Figure 10, the pressure in the ampoule 1002 may be maintained or controlled by pressure flow control which may include a controller and / or flow control valve 1014, which in some implementations may be a throttle valve. As the mixture of inert gas and precursor vapor flows out of the outlet 1010, the pressure flow control of the ampoule flows inert gas into the ampoule 1002 through the inlet 1008 to maintain the pressure in the ampoule 1002. The ampoule also includes an inlet valve 1016 configured to control flow of the inert gas into the ampoule and an outlet valve 1018 configured to control flow out of the outlet 1010, as well as bypass valve 1020 through which the inert gas can flow downstream of the ampoule 1002 without flowing through the ampoule 1002.

[0173] The ampoule 1002 is located in one location of a fabrication facility, such as a "sub-fab," that is different than the location of the semiconductor processing tool, and the processing modules, to where the mixture is flowed. For example, the semiconductor processing tool may be located on a fabrication floor that is a different level in the facility than where the ampoule is located. The different locations of the ampoule and semiconductor processing tool / processing modules is exemplified by the vertical dashed line.

[0174] The mixture of precursor vapor and inert gas is configured to flow out of the outlet 1010 and towards a plurality of flow paths configured to flow the mixture to a plurality of processing modules and into a process volume of each processing module. These flow paths span from the location of the ampoule, e.g., in the sub-fab, to the separate location of the processing tools and / or modules, e.g., the fab floor. The system 1000 of Figure 10 includes four flow paths 1022A-D that each span from the location of the ampoule on the left side of the dashed dividing line,Attorney Docket No. LAM1P147WO-12345-1WO e.g., the sub-fab, to a corresponding processing module 1024A-D on the right side of the dashed dividing line, e.g., on the fab floor. Each flow path 1022A-D is configured to flow the mixture of precursor vapor and inert gas which includes having delivery conduits and other flow elements to contain and directtheflow of mixture to the corresponding processing module 1024A-D. Each flow path is also configured to maintain the mixture at a temperature between about 100 C and 150 C which may include having heating elements that heat the delivery conduits of the flow path and / or thermal insulation around the delivery conduits. Each flow path also has a high-temperature mass flow controller located at or near the corresponding processing module 1024A-D that is configured to control the flow of the mixture along the flow path. Although four flow paths and four processing modules are shown, the number of flow paths and processing modules may vary such that there are 2, 3, 4, 5, 6, 7, 8, or 10 processing modules and corresponding flow paths.

[0175] The foregoing describes implementation of disclosed embodiments in a single or multichamber semiconductor processing tool. The apparatus and process described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, and the like. Typically, though not necessarily, such tools / processes will be used or conducted together in a common fabrication facility. Lithographic patterning of a film typically includes some or all of the following steps, each step provided with a number of possible tools: (1) application of photoresist on a workpiece, i.e., substrate, using a spin-on or spray-on tool; (2) curing of photoresist using a hot plate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or x-ray light with a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern into an underlying film or workpiece by using a dry or plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

[0176] Implementation 1. A method comprising: providing feature comprising an exposed conductive surface and an exposed dielectric surface; and selectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, leaving the dielectric surface exposed.

[0177] Implementation 2. The method of implementation 1, wherein the conductive surface is a surface at a feature bottom and the dielectric surface is a feature sidewall surface.

[0178] Implementation 3. The method of implementation 1, wherein the molybdenum (Mo)-Attorney Docket No. LAM1P147WO-12345-1WO and phosphorus (P)-containing film is MoxPy with x + y being at least 0.99.

[0179] Implementation 4. The method of implementation 1, wherein the molybdenum (Mo)-and phosphorus (P)-containing film is between 50% and 95% (atomic) Mo and between 5% and 50% (atomic) P.

[0180] Implementation 5. The method of implementation 2, further comprising depositing a conformal molybdenum liner on the exposed dielectric surface and the molybdenum- and phosphorus-containing film.

[0181] Implementation 6. The method of implementation 1, further comprising filling the feature with molybdenum.

[0182] Implementation 7. The method of implementation 1, wherein the operations are performed in a single chamber.

[0183] Implementation 8. The method of implementation 1, further comprising, selectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, exposing conductive surface to a metal halide to remove oxide from the conductive surface.

[0184] Implementation 9. The method of implementation 1, wherein the conductive surface comprises copper, molybdenum silicide, titanium carbide, ortitanium aluminum carbide.

[0185] Implementation 10. The method of implementation 1, wherein the molybdenum (Mo)-and phosphorus (P)-containing film is no more than 30 Angstroms thick.

[0186] Implementation 11. The method of implementation 1, further comprising filling the feature with molybdenum.

[0187] Implementation 12. The method of implementation 1, further comprising selectively depositing molybdenum on the molybdenum (Mo)- and phosphorus (P)-containing film.

[0188] Implementation 13. A method comprising: providing a feature to be filled with a conductive material; and depositing a molybdenum (Mo)- and phosphorus (P)-containing film in the feature by an atomic layer deposition (ALD) process comprising exposing the feature to doses of a molybdenum precursor and doses of a phosphorus-containing reactant.

[0189] Implementation 14. The method of implementation 13, wherein the ALD process further comprises exposing the feature to doses of hydrogen (H2).

[0190] Implementation 15. The method of implementation 14, wherein the H2 and phosphorus-containing reactant are co-flowed.

[0191] Implementation 16. The method of implementation 14, wherein the doses of phosphorus-containing reactant and doses of H2 are delivered separately.

Claims

Attorney Docket No. LAM1P147WO-12345-1WO Claims1. A method comprising:providing feature comprising an exposed conductive surface and an exposed dielectric surface; andselectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, leaving the dielectric surface exposed.

2. The method of claim 1, wherein the conductive surface is a surface at a feature bottom and the dielectric surface is a feature sidewall surface.

3. The method of claim 1, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is MoxPy with x + y being at least 0.99.

4. The method of claim 1, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is between 50% and 95% (atomic) Mo and between 5% and 50% (atomic) P.

5. The method of claim 2, further comprising depositing a conformal molybdenum liner on the exposed dielectric surface and the molybdenum- and phosphorus-containing film.

6. The method of claim 1, further comprising filling the feature with molybdenum.

7. The method of claim 1, wherein the operations are performed in a single chamber.

8. The method of claim 1, further comprising, selectively depositing a molybdenum (Mo)- and phosphorus (P)-containing film on the conductive surface, exposing conductive surface to a metal halide to remove oxide from the conductive surface.

9. The method of claim 1, wherein the conductive surface comprises copper, molybdenum silicide, titanium carbide, or titanium aluminum carbide.Attorney Docket No. LAM1P147WO-12345-1WO10. The method of claim 1, wherein the molybdenum (Mo)- and phosphorus (P)-containing film is no more than 30 Angstroms thick.

11. The method of claim 1, further comprising filling the feature with molybdenum.

12. The method of claim 1, further comprising selectively depositing molybdenum on the molybdenum (Mo)- and phosphorus (P)-containing film.

13. A method comprising:providing a feature to be filled with a conductive material; anddepositing a molybdenum (Mo)- and phosphorus (P)-containing film in the feature by an atomic layer deposition (ALD) process comprising exposing the feature to doses of a molybdenum precursor and doses of a phosphorus-containing reactant.

14. The method of claim 13, wherein the ALD process further comprises exposing the feature to doses of hydrogen (H2).

15. The method of claim 14, wherein the H2 and phosphorus-containing reactant are coflowed.

16. The method of claim 14, wherein the doses of phosphorus-containing reactant and doses of H2 are delivered separately.

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