Large grain molybdenum growth in features

Abstract

Provided herein are methods and apparatus for growing molybdenum (Mo) in features. The methods may be used to grow single-grain Mo in features with super-conformal, conformal, and / or top-heavy growth profiles. In some embodiments, methods involve inducing a local crystallization in an amorphous molybdenum-containing material, etching at least a portion of the amorphous molybdenum containing material, and growing the molybdenum crystallites. The methods may be used for bottom-up deposition of Mo in a feature. In some embodiments, then methods may produce molybdenum gap-fill with a reduced number of crystallite grains inside a feature, nearly a single crystalline domain, or a single crystal inside a feature. The methods may be used for logic and memory applications.

Description

LARGE GRAIN MOLYBDENUM GROWTH IN FEATURESCROSS-REFERENCES

[0001] 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

[0002] 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. In an example of deposition, a tungsten (W) layer may be deposited on a titanium nitride (TiN) barrier layer to form a TiN / W bilayer by chemical vapor deposition (CVD) process using tungsten hexafluoride (WFe). However, as devices shrink and more complex patterning schemes are utilized in the industry, the deposition of thin tungsten becomes a challenge. The continued decrease in feature size and film thickness brings various challenges to TiN / W film stacks. These include high resistivity for thinner films and deterioration of TiN barrier properties. Deposition in complex high aspect ratio structures such as 3D NAND structures is particularly challenging.

[0003] For some applications, molybdenum (Mo) offers several benefits over other metals such as cobalt (Co), ruthenium (Ru), and tungsten (W): (i) barrierless and linerless deposition is more feasible on oxides and nitrides as compared to deposition of cobalt, ruthenium, and tungsten, (ii) Mo resistivity scaling is better than that of tungsten, (hi) Mo intermixing with underlying Co is not expected compared to Ru intermixing with Co at temperatures less than 450°C, and (iv) there is relatively easy Mo integration into current W schemes compared to copper and ruthenium.

[0004] The background description provided herein is for the purpose of generally presenting the context of 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

[0005] Provided herein are methods and apparatus for molybdenum (Mo) crystallites to fill features. The methods and apparatus provided herein may be used to grow single-grain Mo in features with super-conformal, conformal, and / or top-heavy growth profiles.

[0006] One general aspect includes a method of depositing molybdenum by providing a substrate having a layer of amorphous molybdenum-containing material thereon; inducing localcrystallization in the molybdenum-containing layer to form molybdenum crystallites separated by regions of amorphous molybdenum-containing material; and exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum- containing material and grow a molybdenum crystallite.

[0007] Implementations may include one or more of the following features.

[0008] In some embodiments, the method may further include growing the amorphous molybdenum-containing material to a thickness of no more than 10 angstroms.

[0009] In some embodiments, inducing local crystallization may include exposing the molybdenum-containing layer to a plasma. In some embodiments, inducing local crystallization may include exposing the molybdenum-containing layer to a temperature between 300 °C and 500 °C.

[0010] In some embodiments, exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing material and grow the molybdenum crystallites may include a first operation of exposing the substrate to a molybdenum chloride precursor without a reducing agent to etch without forming molybdenum and a second operation of exposing the substrate to a molybdenum halide precursor and a reducing agent to deposit molybdenum. In some embodiments, the second operation may include an atomic layer deposition process.

[0011] In some embodiments, exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing material and grow the molybdenum crystallite may include an atomic layer deposition process using a molybdenum chloride and reducing agent. In some embodiment, the molybdenum chloride precursor is MoCb.

[0012] One general aspect includes a method of depositing molybdenum in a feature. The method includes providing a feature in a substrate having a layer of amorphous molybdenum-containing material at the feature bottom; inducing local crystallization in the molybdenum-containing layer to form, at the feature bottom, molybdenum crystallites separated by regions of amorphous molybdenum-containing material, each crystallite, independently, having a Mo (100), Mo (111), or Mo (110) orientation; exposing the substrate to a molybdenum chloride precursor to etch one or more crystallites, leaving one crystallite remaining at the feature bottom; and growing the remaining cry stallite to form a single-grain seed layer at the feature bottom.

[0013] Implementations may include one or more of the following features. In some embodiments, exposing the substrate to a molybdenum chloride precursor etches at least one of Mo (111) and Mo (100) orientations.

[0014] In some embodiments, the single-grain seed layer may include the Mo (110) orientation.

[0015] In some embodiments, the molybdenum chloride precursor is M0CI5.

[0016] In some embodiments, the method may include growing the amorphous molybdenum- containing layer to a thickness of no more than 10 angstroms.

[0017] In some embodiments, inducing local crystallization may include exposing the molybdenum-containing layer to a plasma. In some embodiments, inducing local crystallization may include exposing the molybdenum-containing layer to a temperature between 300 °C and 500 °C.

[0018] In some embodiments, growing the remaining crystallite to form a single-grain seed layer may include exposing the substrate to a molybdenum chloride precursor. In some embodiments, substrate may be exposed e to a very high dose of M0CI5.

[0019] In some embodiments, the method of depositing molybdenum in a featured may include exposing the feature bottom to a molybdenum halide precursor and a reducing agent to deposit molybdenum in the feature. In some embodiments, the molybdenum deposited in the feature may include a single grain Mo (110). Some embodiments may involve atomic layer deposition process.BRIEF DESCRIPTION OF DRAWINGS

[0020] Figures 1A and IB are illustrative comparisons of the feature fill with small horizontal grains and large horizontal grains, respectively.

[0021] Figures 2A and 2B are schematic examples of material stacks that include molybdenum layers according to various embodiments.

[0022] Figures 3A - 3L are schematic examples of various structures into which molybdenum may be deposited in accordance with disclosed embodiments.

[0023] Figure 4 shows a process flow diagram illustrating example operations in a method of depositing molybdenum.

[0024] Figures 5 - 10 show illustrative examples of the method for depositing molybdenum according to various embodiments.

[0025] Figure 11 shows a process flow diagram illustrating example operations in a method for bottom-up deposition of molybdenum inside a feature.

[0026] Figure 12 shows illustrative examples of bottom-up deposition of molybdenum inside a feature according to various embodiments.

[0027] Figure 13 is a process flow diagram illustrating example operations in a method of filling a feature with molybdenum.

[0028] Figure 14 is a process flow diagram illustrating a method to fill a feature with a molybdenum (Mo) film.

[0029] Figure 15 is a process flow diagram illustrating a method to fill a feature with a MO film.

[0030] Figure 16 illustrates the interplay of growth and etch components of molybdenum crystallite when using M0CI5 precursor, and the net effect on different cry stalline phases of molybdenum.

[0031] Figures 17 and 18 show examples of processing systems that may be used to implement the methods described herein.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] Provided herein are methods and apparatus for growing single-grain molybdenum (Mo) via deposition-etch-deposition processing. The methods and apparatus provided herein may be used to grow single-grain Mo in features with super-conformal, conformal, and / or top-heavy growth profiles. The method of filling features with Mo may be used for logic and memory' applications. The Mo films may be deposited in semiconductor substrate features such as vias and trenches. The Mo film may be deposited to line features as liner layer and / or fill features.

[0034] In some embodiments, the methods involve bottom-up deposition of Mo in a feature. Bottom-up deposition refers to growth that is mostly or wholly from a feature bottom relative to the feature sidewalls. Using conventional deposition methods to fill feature can result in 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 may7form as growth at the top of the feature can pinch off the feature. A seam can form in the center of a feature as the film grows inward from the sidewalls. Bottom-up deposition can avoid the formation of voids and seams in the feature during the filling process.

[0035] The methods provided herein may be used to deposit molybdenum on a substrate and inside a feature on the substrate, thereby reducing resistivity. In various implementations, the method can be used to deposit molybdenum with large horizontal grains on a substrate and / or inside a feature. As used herein the term "horizontal grain" refers to a crystallite formed along a surface of the feature, where the direction of crystallite growth is largely parallel to the surface. The longest dimension of a horizontal grain is also typically in the direction of growth, parallel to the surface. Depending on the orientation of the feature and the surface on which the growth occurs, ahorizontal grain may be oriented parallel or orthogonal to the plane of the semiconductor wafer or other substrate.

[0036] The term ‘amorphous’ refers to a substantially amorphous material that lacks long-range order. In various embodiments, some amount of crystallites or nucleates may be present.

[0037] The term ‘local crystallization’ refers to a material where regions of one or more crystallites are separated by regions of amorphous material.

[0038] The term ‘molybdenum-containing material’ includes any material that contains molybdenum. This includes pure molybdenum and substantially pure molybdenum. Substantially pure molybdenum refers to molybdenum that contains no more than trace amounts of other materials. For example, substantially pure molybdenum may be at least 99.9% molybdenum. In some embodiments, impurities may be present in larger concentrations in a molybdenum- containing material, and / or the molybdenum-containing material may be a compound material. For example, oxygen contaminants may be present within the molybdenum-containing material with the molybdenum-containing material being or including a layer of molybdenum-oxide. Figures 1 A and IB are illustrative comparisons of the feature fdl with small grains and large horizontal grains. Figure 1 A shows the grow th of small grains inside a feature. In some cases, the small grains are not horizontally oriented. For example, the longest dimension of grain may be away from, or orthogonal to, the underlying surface on which growth originates. A feature filled with small grains may increase the number of grain boundaries, thereby increasing the resistivity. In contrast, Figure IB shows the growth of large horizontal grains inside a feature. As depicted in Figure IB, the large horizontal grains are formed along the surface of the feature, where the longest dimension of the horizontal grains is parallel to the surface. A feature filled with large horizontal grains may reduce the number of grain boundaries and reduce the resistivity.

[0039] Molybdenum feature fill via slow; atomic layer deposition may result in the growth of small horizontal grains, and cause voids and seams inside the feature.

[0040] The methods provided herein may grow molybdenum crystallite with large horizontal grains across the feature, and / or may be used to grow a single grain molybdenum inside the feature.

[0041] The molybdenum crystallites deposited using the method provided herein may have various molybdenum crystalline phases. For example, each of the deposited molybdenum crystallites, independently, may be of Mo (100), Mo (111), and / or Mo (110) orientation.

[0042] Figures 2A and 2B are schematic examples of material stacks that include Mo layers according to various embodiments. Figures 2A and 2B illustrate the order of materials in examples of particular stacks and may be used with any appropriate architecture and application, as described further below with respect to figures 3A-3L. Figure 2A shows a first material stack 211 featuring a substrate 202 and a molybdenum layer 208 deposited thereon. The substrate 202 maybe 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 202 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.

[0043] The stack 211 has a dielectric layer 204 on the substrate 202. The dielectric layer 204 may be deposited directly on a semiconductor surface (e.g., a Si or SiGe surface) of the substrate 202, or there may be any number of intervening layers. For example, substrate 202 may include any number of layers deposited in various arrangements on a semiconductor substrate.

[0044] Examples of dielectric layers include doped and undoped silicon oxide, silicon nitride, and aluminum oxide layers, with specific examples including doped or 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 211 has a layer 206 disposed between the molybdenum layer 208 and the dielectric layer 204. The layer 206 may be a diffusion barrier and / or adhesion layer, for example. A diffusion barrier is a layer that prevents the 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 layer 208 is the main conductor of the structure. In some embodiments, the molybdenum layer 208 may include multiple bulk layers deposited at different conditions. The molybdenum layer 208 may or may not include a molybdenum nucleation layer. In some embodiments, molybdenum layer 208 is an amorphous molybdenum-containing layer. In the depicted example of Figure 2A, the molybdenum layer 208 is deposited directly on the layer 206. In other embodiments (not depicted), the molybdenum layer 208 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 molybdenum layer 208.

[0045] Figure 2B shows another example of a stack 221. In this example, the stack 221 includes the substrate 202, dielectric layer 204, with molybdenum layer 208 deposited directly on the dielectric layer 204, without an intervening diffusion barrier or adhesion layer. The molybdenum layer 208 is as described with respect to Figure 2A. By using molybdenum as the main conductor, low-resistivity thin films can be obtained. Examples of low-resisli vity 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.

[0046] In some embodiments, a stack (not shown) may include a substrate, a conductive layer, and a molybdenum layer deposited onto the conductive layer. As used herein. A conductive layer is a layer having a conductivity of at least 104Q'l-cm-1at room temperature. Examples include molybdenum on a metal layer (e g., a W layer, or another Mo layer). In these embodiments, there is no dielectric layer between the molybdenum layer and the conductive layer. Similarly, the stack may include molybdenum deposited directly on a metal compound layer. Examples include molybdenum 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 layer deposited directly on the substrate, including directly on a semiconducting surface, on a dielectric surface, or a conductive surface. Figures 2A and 2B illustrate examples of the order of materials in a particular stack and may be used with any appropriate architecture and application, with examples described further below with respect to figures 3A-3L.

[0047] 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 fill any feature with molybdenum.

[0048] 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.

[0049] Figure 3A depicts a schematic example of a DRAM architecture, including a Mo buried wordline (bWL) 308 in a silicon substrate 302. The Mo bWL is formed in a trench etched in the silicon substrate 302. Lining the trench is a conformal barrier layer 306 and an insulating layer 304. The conformal barrier layer 306 is disposed between the insulating layer 304 and the silicon substrate 302. In this example, the insulating layer 304 may be a gate oxide layer formed from a high-k dielectric material such as silicon oxide or silicon nitride material. In some embodiments disclosed herein, the conformal barrier layer 306 is TiN or tungsten-containing layer, such as WN or WCN layer. In some embodiments, a conformal tungsten-containing growth initiation layer (not showTi) may be present between the conformal barrier layer 306 and the molybdenum bWL 308. Alternatively, the molybdenum bWL 308 may be deposited directly on a Tin or other diffusion barrier. In some embodiments, one or both of layers 304 and 306 is not present.

[0050] The bWL structure shown in Figure 3A is one example of an architecture that includes a molybdenum fill layer. During fabrication of the WL, molybdenum is deposited into a feature that may be defined by an etched recess in the silicon substrate 304 that is conformally lined with layers 306 and / or 304, if present.

[0051] Figures 3B - 3H are additional schematic examples of various structures into which molybdenum may be deposited in accordance with disclosed embodiments. Figure 3B shows an example of a cross-sectional depiction of a vertical feature 301 to be filled with Mo. The feature can include a feature hole 305 in a silicon substrate 302. The feature hole 305 may have an underlayer 303 lining the sidewall or interior of the feature hole 305 and may form the interior surfaces. The feature hole 305 or other features may have a dimension near the opening, e.g., an opening diameter or line width of between about 10 nm to 500 nm, for example, between about 25 nm to about 300 nm. The feature hole 305 can be referred to as an unfilled feature or simply a feature. The vertical feature 301, and any feature, may be characterized in part by an axis 318 that extends through the length of the feature, with vertically oriented feature having vertical axes and horizontally oriented feature having horizontal axes. The underlayer 303 can be, for example, a diffusion barrier layer, an adhesion layer, a nucleation layer, a combination 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 SiCh. 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 SiCh. 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 underlayer is tungsten-free. In some embodiments, the underlayer is molybdenum-free.

[0052] 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 200 A 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 features may have an underlayer, such as a barrier layer or adhesion layer. Non-limiting examples of underlayers include dielectric layers and conducting layers, e.g., silicon oxides, silicon nitrides, silicon carbides, metal oxides, metal nitrides, metal carbides, and metal layers.

[0053] Figure 3C shows an example of a vertical feature 301 that has a re-entrant profile. A reentrant profile is a profile that narrows from the 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 3C shows an example of the latter, withan underlayer 313 lining the sidewall or interior surfaces of the feature hole 305. Similar to Figure 3B, underlayer 313 can be a diffusion barrier layer, an adhesion layer, a nucleation layer, a combination thereof, or any other applicable material. Non-limiting examples of underlayers can include dielectric layers and conducting layers. The underlayer 313 forms an overhang 315 such that the underlayer 313 is thicker near the opening of the vertical feature 301 than inside the vertical feature 301.

[0054] In some implementations, features have one or more constrictions within the feature may be filled. Figure 3D shows examples of views of various filled features having constrictions. Each of the examples (a), (b), and (c) in Figure 3D includes a constriction 309 at a midpoint within the feature. The constriction 309 can be, for example, between about 15 nm - 20 nm wide. Constrictions can cause pinch off during the 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 315 (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 312 further away from the field region than the overhang 315 in example (b).

[0055] Horizontal features, such as in 3D memory' structures, can also be filled. Figure 3E shows an example of a horizontal feature 350 that includes a constriction 351. For example, horizontal feature 350 may be a wordline in a 3D 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 3F presents a cross-sectional side view of a 3D NAND structure 310 (formed on a silicon substrate 302) having 3D NAND stack (left 325 and right 326), central vertical structure 330, and the plurality of stacked horizontal wordline features 320 with opening 322 on opposite sidewalls 340 of central vertical structure 330. Note that Figure 3F displays two “stacks” of the exhibited 3D NAND structure 310, which together form the “trench-like” central vertical structure 330. However, in certain embodiments, there may be more than two such stacks arranged in sequence and running spatially parallel to one another, the gap between each adjacent pair of s stacks forming a central vertical structure 330, like that explicitly illustrated in Figure 3F. In this embodiment, the horizontal wordline features 320 are 3D memory wordline features that are fluidically accessible from the central vertical structure 330 through the openings 322. Although not explicitly indicated in the figure, the horizontal wordline feature 320 present in both the 3D NAND stacks 325 and 326 shown in Figure 3F (i.e., the left 3D NAND stack 325 and the right 3D NAND stack 326) are also accessible from the other sides of the stacks (far left and far right, respectively) through similar vertical structures formed by additional 3D NAND stacks (to the far left and far right, but now shown). Each 3D NAND stack 325, 326 contains a stack ofwordline features that are fluidically accessible from both sides of the 3D NAND stack through a central vertical structure 330. In the particular example schematically illustrated in Figure 3F, each 3D NAND stack contains 6 pairs of stacked wordlines. However, 3D NAND memory layout may contain any number of vertically stacked pairs of wordlines.

[0056] The wordline features in a 3D 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 maybe vertically stacked in such a 3D 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 wordline features, and so forth (the listed ranges understood to include either recited endpoints).

[0057] Figure 3G presents a cross-sectional top-down view of the same 3D NAND structure 310 shown in the side view in Figure 3F with the cross-section taken through the horizontal section 360 as indicated by the dashed horizontal line in Figure 3F. The cross-section of Figure 3G illustrates several rows of pillars 355, which are shown in Figure 2F to run vertically from the base of the substrate 302 to the top of the 3D NAND structure 310. In some embodiments, the pillars 355 are formed from a polysilicon material and are structurally and functionally significant to the 3D NAND structure 310. In some embodiments, such polysilicon pillars may serve as gate electrodes for stacked memory cells formed within the pillars. The top-view of Figure 3G illustrates that the pillars 355 form constrictions in the opening 322 to wordline feature 320. Fluidic accessibility of wordline features 320 from the central vertical structure 330 via opening 322 (as indicated by the arrows in Figure 3G) is inhibited by pillars 355. 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 320 with the material. The structure of the wordline features 320 and the challenges of uniformly filling the with molybdenum material due to the presence of pillars 355 is further illustrated in Figures 3H, 31, and 3J.

[0058] Figure 3H exhibits a vertical cut through a 3D NAND structure similar to that shown in figure 3F, but here focused on a single pair of wordline features 320 and additionally schematically illustrating a fill process which resulted in the formation of a void 375 in the filled wordline feature 320. Figure 31. also schematically illustrates void 375, but in this figure illustrated via a horizontal cut through pillars 355, similar to the horizontal cut exhibited in Figure 3G. Figure 3J illustrates the accumulation of molybdenum material around the constriction-forming pillars 355, theaccumulation resulting in the pinch-off of opening 322, so that no additional molybdenum material can be deposited in the region of voids 375. Apparent from Figures 3H and 31 is that void-free molybdenum fill relies on migration of sufficient quantities of deposition precursor dow n through central vertical structure 330, through openings 322, past the constricting pillars 355, and into the furthest reaches of the wordline feature 320. prior to the accumulated deposition of molybdenum around pillars 355 causing a pinch-off of the openings 322 and preventing further precursor migration into wordline features 320. Similarly, Figure 3J exhibits a single wordline feature 320 viewed cross-sectionally from above and illustrates how a generally conformal deposition of molybdenum material begins to pinch-off the interior of wordline feature 320 due to the fact that the significant width of pillars 355 acts to particularly block, and / or narrow, and / or constrict what would otherwise be an open path through wordline feature 320. (It should be noted that the example in Figure 3J can be understood as a 2D rendering of the 3D features of the structure of the pillar constrictions shown in Figure 31, thus illustrating constrictions that w ould be seen in plan view rather than in a cross-sectional view.)

[0059] Three-dimensional structures may need longer and / or more concentrated exposure to precursors to allow7the 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.

[0060] Figures 3K and 3L show examples of asymmetric trench structure DRAM bWL. Some fill processes for DRAM bWL trenches can distort the trenches such that the final trench width and resistance Rs are significantly non-uniform. Figure 3K shows an unfilled feature 361 and filled feature 365 that exhibits the line bending after fill. In this example, the features are a narrow asymmetric trench structure DRAM bWL. As shown, multiple features 383 are depicted on a substrate. These features 383 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 361 may be generally V-shaped, as shown in feature 383, having sloped sidew alls w here 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 373b to the feature top 373a. After some fill operations, line bending may be observed within the filled feature 365. In some situations, a cohesive force between opposing surfaces of a trench pulls the trench sides together, as depicted by arrows 367. The phenomenon is illustrated in Figure 3L and may be characterized as ’‘zipping up’' the feature. As the feature 383 is filled, more force is exerted from a center axis 399 of the feature 383, causing line bending. For example, molybdenum may be deposited on the sidewallsof the feature 383. Deposited molybdenum 384a and 384b on sidewalls of feature 383 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.

[0061] Provided below are methods of depositing molybdenum. The methods described herein may be used to deposit molybdenum on a substrate. The substrate may be any featured substrate. In some embodiments, molybdenum is deposited on a material stack and / or in a featured substrate, for example as shown in the example of Figures 2A-B and 3A-L.

[0062] Figure 4 is a process flow diagram illustrating example operations in a method of depositing molybdenum. Process 400 begins with operation 401, in which a substrate having a layer of amorphous molybdenum (Mo)-containing material is provided. Local crystallization in the molybdenum-containing material is induced in operation 403. In operation 403, molybdenum crystallites separated by regions of amorphous molybdenum-containing materials may be formed. In operation 405, the substrate is exposed to a molybdenum chloride precursor. The exposure to molybdenum chloride precursor etches at least a portion of the amorphous molybdenum- containing material and grows the molybdenum crystallites.

[0063] Referring to operation 401, in some embodiments, the substrate on which the amorphous Mo-containing material is deposited may be a non-crystalline template. Non-crystalline templates include amorphous and / or small-grained poly crystalline surfaces. The non-crystalline template is used to facilitate the growth of amorphous Mo-containing material. The non-crystalline template may include any non-pure metal. For example, in some embodiments, the non-crystalline template may be a dielectric material, silicon, silicon oxide, silicon dioxide, silicon nitride, or combinations thereof. In a particular example, a non-crystalline template may be amorphous silicon. In some embodiments, non-crystalline templates may contain metals that are composed of small grains or are amorphous. For example, titanium nitride, titanium silicide, hafnium oxide, titanium carbides.

[0064] In some embodiments, the substrate may include a material stack that includes an amorphous molybdenum-containing material at the top of the stack. Such a layer may be deposited on the substrate by reacting a molybdenum-containing precursor (also referred to as a molybdenum precursor) with a co-reactant. In some embodiments, a molybdenum halide compound such as molybdenum pentachloride (Mods) or moly bdenum dichloride dioxide (MO2O2CI2) may be used. The amorphous molybdenum-containing layer may be deposited by implementing various deposition techniques. For example, atomic layer deposition (ALD) and chemical vapor deposition (CVD), either of which may be thermal-, or plasma-enhanced. The amorphous molybdenum- containing layer may be deposited using MOO2CI2 and / or M0CI5, or using any other suitable molybdenum-containing precursor. In some embodiments, the amorphous molybdenum-containing layer may be deposited with a reducing agent (e.g., H2). Methods may include surface treatment using a molybdenum halide compound, which may be the same or a different compound used in deposition. Further details on molybdenum deposition are provided below.

[0065] In various embodiments, the layer of amorphous molybdenum-containing material may be a thin layer. The thickness of such a layer may be between about 5 A and about 10 A. In some embodiments, thickness is 5 A or 10 A. In some embodiments, the thickness may be less than 5 A or 10 A. In some embodiments, the thickness may no more than 10 A. In some embodiments, crystallization of the molybdenum may begin at a thickness above about 10 A.

[0066] In some embodiments, the amorphous molybdenum-containing material may be pure molybdenum. Pure molybdenum refers to molybdenum having no more than trace amounts of other materials. Pure molybdenum contains at least 99.9% molybdenum.

[0067] In other embodiments, the amorphous molybdenum-containing material may include impurities that can hinder the conductivity of the molybdenum film. For example, impurities may be oxygen contaminants, and the oxygen contaminants may be present within the amorphous molybdenum-containing material. In other embodiments, impurities may be molybdenum oxide. For example, molybdenum oxide may be presented as a layer on top, and / or on the surface of, the deposited amorphous molybdenum-containing layer.

[0068] In some implementations, operation 401 may optionally include removing a molybdenum oxide layer, oxide impurities, and / or any other impurities present in the amorphous molybdenum- containing material by dry etching of the surface. In some embodiments, dry etching may involve exposure to molybdenum halides, for example, M0CI5. In some such embodiments, MoCh-based dry etching may be performed at a low temperature and / or with a low dose of M0CI5 to avoid overetching. In some embodiments, dry etching during operation 401 may involve pulsing M0CI5.

[0069] In various embodiments, operation 401 may optionally include depositing additional amorphous molybdenum-containing material is deposited. Deposition of additional amorphous molybdenum-containing material may involve any suitable molybdenum deposition methods. For example, slow thermal ALD using M0CI5 precursor with or without H2 or PEALD with M0CI5 precursor with or without H2 may be used. Other suitable ALD or CVD methods may be used with an appropriate molybdenum-containing precursor.

[0070] In some instances, the additional amorphous molybdenum-containing material is deposited to a thickness below, or about equal to the critical thickness of crystallization. The critical thickness of crystallization refers to the thickness at which crystallization initiates. The critical thickness of crystallization may vary depending on the temperature conditions. For example, a critical thickness of crystallization may be larger at lower temperatures while smaller at higher temperatures. In some embodiments, the deposition of additional amorphous molybdenum-containing material may be performed slowly to prevent triggering a nucleation / crystallization of the molybdenum. For example, additional amorphous molybdenum-containing material may be grown at less than 0. 1 A per cycle, and / or less than 0.5 A per minute.

[0071] In some embodiments, the slow grow th of additional amorphous molybdenum-containing material is controlled by the dose of the molybdenum-containing precursor. For example, the slow growth of amorphous molybdenum-containing material may be attained by ALD at a relatively low7dose of molybdenum-containing precursor such as M0CI5. Alternatively, slow7growth of amorphous moly bdenum-containing material may be achieved by ALD with a high dose of molybdenum-containing precursor that also can etch, such as M0CI5. At high doses with M0CI5, amorphous molybdenum-containing matenal is being deposited and etched concurrently and / or alternatively, thereby allowing control of the deposition rate. A slow net growth of amorphous molybdenum-containing material can be achieved even at high doses of molybdenum-containing precursor.

[0072] In various implementations, the high-dose process may be characterized as a process, e.g., ALD, where the molybdenum-containing precursor dose is 8 times or more compared to a low- dose process.

[0073] Operation 401 may be performed at moderately low temperatures or at high temperatures, between about 325 °C and 375 °C. between 350 °C and 450 °C. or between 300 °C and 500 °C.

[0074] In some embodiments, the optional dry etching and optional deposition of additional amorphous molybdenum-containing material may be performed at the same temperature as other processes of operation 401. In some embodiments, each of the processes of operation 401 may, independently, be performed at different temperatures.

[0075] In operation 403. local crystallization in the molybdenum-containing material is induced, forming molybdenum crystallites separated by regions of amorphous molybdenum-containing material. As the amorphous molybdenum-containing material is consumed by crystallization, its thickness will decrease. The initial molybdenum crystallites, formed within amorphous molybdenum-containing material, cease crystallizing once the regions of the amorphous molybdenum-containing material separating each crystallite reach a thickness below the critical thickness.

[0076] Local crystallization in the molybdenum-containing material may be triggered by thickness, temperature conditions, or an interplay of both thickness and temperature conditions. In some embodiments, the thickness and temperature conditions may inversely influence local crystallization in the molybdenum-containing material. For instance, crystallization at increasing temperatures may begin at decreasing thicknesses of molybdenum-containing material. Alternatively, crystallization may begin at lower temperatures with increasing thicknesses ofmolybdenum-containing material. In some embodiments, different thicknesses may be selected depending on the available thermal budget.

[0077] Local cry stallization of the molybdenum-containing material may occur at relatively moderate temperatures as amorphous molybdenum tends to be relatively “mobile”.

[0078] In some embodiments, local crystallization is triggered by changes to local film thickness. For example, local fluctuations of the film thickness, where regions of amorphous molybdenum- containing material exceed a critical thickness of crystallization, can initiate the local ciystallization / nucleation in the molybdenum-containing material. In some embodiments, the local thickness may be between about 5 A and about 10 A, more than 5 A. or more than 10 A to reach or exceed a critical thickness for crystallization.

[0079] In some embodiments, local crystallization in the molybdenum-containing material is triggered in response to temperature conditions. For example, a high temperature may induce fluctuations in the thickness of the molybdenum-containing film surface, which in turn leads to local crystallization in the molybdenum-containing material. Lower temperatures may accommodate a larger thickness of amorphous molybdenum-containing material before crystallization begins than higher temperatures. In some embodiments, temperatures inducing local crystallization may be about 480 °C, corresponding to approximately 19% of the molybdenum melting point, between 325 °C and 375 °C, between 350 °C and 450 °C, or between 300 °C and 500 °C.

[0080] In some embodiments, the temperature for inducing local crystallization in operation 403 may be the same as the temperature for the process of slow grow th of the additional amorphous molybdenum-containing material or operation 401. For example, both operations 401 and 403 may be between about 325 °C and 375 °C, between 350 °C and 450 °C. or between 300 °C and 500 °C.

[0081] In some embodiments, the temperature for inducing local crystallization in operation 403 may be different from the temperature for the process of slow grow th of the additional amorphous molybdenum-containing material or operation 401.

[0082] In some embodiments, the local crystallization in the molybdenum-containing material is triggered by a plasma process. For example, amorphous molybdenum-containing material may be exposed to a suitable plasma, e.g., a plasma generated from argon or hydrogen gas. The plasma process may be performed in addition to or in the absence of the aforementioned crystallization initiation process via temperature and / or thickness conditions to induce crystallization of the molybdenum-containing material.

[0083] In some embodiments, operation 403 may optionally include further deposition of amorphous molybdenum-containing material. In some embodiments, amorphous molybdenum-containing material is deposited on the surface of molybdenum crystallites and / or amorphous regions separating the crystallites. In various embodiments, the amorphous molybdenum- containing material is deposited at a slow rate. In some implementations, amorphous molybdenum-containing material is grown at less than 0.1 A per cycle, and / or less than 0.5 A per minute. The continued growth of amorphous molybdenum-containing material may involve atomic layer deposition (ALD) and chemical vapor deposition (CVD), or other suitable deposition methods. ALD and CVD may be thermal-, or plasma-enhanced. The amorphous molybdenum- containing layer may be deposited using Mods precursor or using any other suitable molybdenum-containing precursor. In some embodiments, the amorphous molybdenum- containing layer may be deposited with a reducing agent (e.g., H2). In some embodiments, further deposition of amorphous molybdenum-containing material is a slow process. In some embodiments, further deposition of amorphous molybdenum-containing material is performed without triggering the nucleation of additional crystallites.

[0084] In various embodiments, the thickness of the amorphous molybdenum-containing material, in the regions between the molybdenum crystallites and / or amorphous molybdenum-containing material deposited over the molybdenum cry stallites, may be thin (e.g., no more than about 10 A) to prevent additional, parasitic crystallization.

[0085] In some embodiments, the optional deposition of amorphous molybdenum-containing material involves a low dose of M0CI5 ALD. In some embodiments, the optional deposition of amorphous molybdenum-containing material involves a high dose of M0CI5 ALD, which include both deposition and etch components, with a slow net deposition rate.

[0086] In some embodiments, the optional deposition of amorphous molybdenum-containing material may be performed at temperatures between about 325 °C and 375 °C, between 350 °C and 450 °C, or between 300 °C and 500 °C.

[0087] In some embodiments, the temperature for optional deposition of amorphous molybdenum-containing material in operation 403 may be the same as the temperature in operation 401, or any other processes in operation 403.

[0088] In some embodiments, the temperature for optional deposition of amorphous molybdenum-containing material in operation 403 may be different from the temperature in operation 401, or any other processes in operation 403.

[0089] In some embodiments, operation 403 may optionally include continued growth of the molybdenum crystallites. In such embodiments, the amorphous molybdenum-containing material between the crystallites is consumed as the crystallites grow. In such embodiments, the molybdenum cry stallite grows selectively in a lateral or horizontal direction, where the grow th is parallel to, or in a plane, or along the substrate or feature. In some embodiments, the molybdenumcrystallite grows both in the lateral or horizontal direction, parallel to, or in a plane, or along the substrate or feature, as well as in the vertical direction, orthogonal to the plane of the substrate or feature, increasing its thickness.

[0090] In some embodiments, initial crystallites may continue to grow until terminated by another crystallite to form long horizontal grains of molybdenum, without introducing additional nucleation of crystallites.

[0091] In various embodiments, continued growth of the molybdenum crystallites involves a slow deposition method. As described above, slow' ALD growth can be achieved with either a high dose of MoCh, incorporating both deposition and etch components, with a slow net deposition rate or a low' dose MoCb.

[0092] According to various embodiments, the temperature for optional, continued growth of molybdenum cry stallites in operation 403 may be the same as or different from the temperature in operation 401, or any other processes in operation 403.

[0093] In some implementations, the deposition of amorphous molybdenum-containing material and the growth of molybdenum crystal 1 i tes may occur in a single operation. For example, an ALD dose of M0CI5 may be selected such that amorphous molybdenum-containing material is etched at a faster rate than the cry stalline molybdenum. In some embodiments, the growth of molybdenum crystallite may be accompanied by zero net growth of amorphous molybdenum-containing material. In some embodiments, once the initial local crystallization of molybdenum is achieved, the dose of M0CI5 may be increased to allow crystalline molybdenum to continue to grow' while the amorphous molybdenum-containing material ceases to grow'. The dose can be tailored to achieve an appropriate level of molybdenum growth, including zero net growth of amorphous molybdenum. In some embodiments, the growth of molybdenum crystallites may be accompanied by net negative growth of amorphous molybdenum-containing material. That is, the dose of M0CI5 etches amorphous molybdenum during the growth of a cry stallite.

[0094] In some embodiments, when using ALD with a high dose of M0CI5, the potential for extra nucleation of molybdenum crystallite is reduced, or even eliminated. Under such circumstances, initial molybdenum crystallite may continue to grow' until terminated by another molybdenum crystallite without additional nucleation.

[0095] Various processes described for operation 403 may be performed at the same or different temperatures.

[0096] During operation 405, at least a portion of the amorphous molybdenum-containing material is etched and grows molybdenum crystallite. In some embodiment, substrate, with molybdenum cry stallites and optionally amorphous molybdenum-containing material deposited thereon, may be exposed to a molybdenum chloride precursor, e.g., M0CI5, to etch at least a portion of theamorphous molybdenum-containing material and to grow molybdenum crystallite. While operation 405 is described in the context of M0CI5, any other molybdenum halide capable of etching amorphous molybdenum-containing material may be used. Molybdenum halides capable of etching include, but are not limited to, molybdenum chlorides such as M0CI4 and M0CI5.

[0097] In some embodiments, exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing material and grow the molybdenum crystallite may include two separate operations. For example, in some embodiments, the first operation exposes the substrate to a molybdenum chloride precursor without a reducing agent to etch amorphous molybdenum-containing material without forming molybdenum. The second operation exposes the substrate to a molybdenum halide precursor and a reducing agent, depositing molybdenum. In some embodiments, the first and / or second operations may involve ALD, for example, ALD using molybdenum chloride and a reducing agent. In some other embodiments, as described above, the two operations may occur at least partially concurrently. .

[0098] In some embodiments, operation 405 may involve high growth rate thermal or plasma ALD, and / or ALD with M0CI5 with or without H2.

[0099] In some embodiments, operation 405 is performed using a high dose of M0CI5 for the ALD process. The high dose of M0CI5 pulse may include both an etching component and a deposition component.

[0100] The high dose of M0CI5 pulse includes a substantial etching component that etches away defective regions of Mo crystallite grain boundaries and / or defective surfaces purifying the crystalline structure of the Mo grains and may prevent intercalation of the impurities in the body of the cry stallite. In some embodiments, operation 405 may also eliminate surface irregularities. In some embodiments, high-dose MoCh may etch defective surfaces at a faster rate than molybdenum crystallites.

[0101] The high dose of M0CI5 pulse may include a deposition component. M0CI5 may adsorb, for example, chemisorb or physisorb, to the surfaces (molybdenum crystallites and / or amorphous molybdenum-containing material) during the ALD process. In various embodiments, surface- adsorbed M0CI5 may react with a reducing agent pulse, e g., H2 or H2 plasma, to deposit molybdenum-containing material.

[0102] In some embodiments, the resulting molybdenum-containing material deposited on the surface may be conformal or superconformal. Conformal deposition refers to the molybdenum- containing material following the contours of the underlying surface with approximately uniform thickness. Superconformal deposition refers to deposition in which the thickness at the top or opening of the feature is greater than the thickness further within the feature. Conformal or superconformal deposition may be a result of reduced dry etching near the bottom compared tonear the top of the feature. The reduced etching is due to the decreased availability of M0CI5 near the bottom compared to near the top of the feature. While etching is decreased due to decreased availability within the feature, the deposition component of the M0CI5 ALD is generally not affected by the relative position on the substrate or within a feature. Rather the deposition is controlled by the available reaction sites, e.g., chemisorbed M0CI5 molecules. Near the feature bottom, generally, more reaction sites are available, resulting in conformal deposition due to increased deposition near the feature bottom. In some embodiments, the extent of conformity’ is determined by the M0CI5 dosage. In addition, the etching of amorphous molybdenum-containing material is also determined by the M0CI5 dosage.

[0103] In some embodiments, operation 405 may be performed at about 450 °C, or at temperatures between about 325 °C and 375 °C, between 350 °C and 450 °C, or between 300 °C and 500 °C. In some embodiments, operation 405 is performed at high temperatures to increase the throughput of the deposition process.

[0104] In some embodiments, operation 405 may be practiced using a moderate dosage of MoCk A moderate dosage of M0CI5 refers to a dosage that does not provide a high etching component. The moderate dosage of M0CI5 may be used in high-growth ALD with or without H2, ALD, or PECVD methods to perform operation 405. The moderate dosage of M0CI5 may not provide a high etching component and promote deposition of conformal or top-heavy superconformal growth profile depending on the methods used. For example, at the moderate dosage, the conformal profile may be produced when using ALD while a top-heavy growth profile may be obtained when using PECVD.

[0105] In some embodiments, superconformal growth and etching of the defective surfaces may be achieved by cycles of MoCh-based dry etching and molybdenum deposition (e.g., ALD with M0CI5 and H2, ALD without plasma, or PECVD). In some embodiments, the extent of superconformality’ may be determined by the ratio of etching and deposition cycles.

[0106] In some embodiments, operation 405 may optionally further include etching the molybdenum cry stallites. If used, this operation can also etch the amorphous molybdenum- containing material on the surface of, and / or between the regions of molybdenum crystallites. This may be performed prior to high grow th rate and high throughput deposition of molybdenum- containing material and may involve high dose ALD. In some embodiments, this operation reduces the thickness of the molybdenum crystallites to about 10 A. In some embodiments, this optional etching of molybdenum crystallites is performed at a low temperature with MoCkbased dry etching. In some embodiments, it may be performed at temperatures between about 325 °C and 375 °C, between 350 °C and 450 °C, or between 300 °C and 500 °C. In some embodiments, thisoptional etching of molybdenum crystallites may be performed at the same or different temperatures from other processes in operation 405.

[0107] Figure 5 is an example of operation 400 practiced with all optional operations described above. Figures 6-10 provides examples of operation 400 practiced without some of the operations described above.

[0108] Figure 5 provides an example of process 400 where all optional operations that are described above are performed. In this example, process 400 begins with providing a substrate 515 having a layer of amorphous molybdenum-containing material 513a. In this example, the substrate 515 has a layer of molybdenum oxide 510 impurities residing over the amorphous molybdenum-containing material 513a. By operation 501, molybdenum oxide impurities 510 (and other impurities) are removed by dry etching of the surface with MoCh, thereby exposing the amorphous molybdenum-containing material 513b. Next, in operation 502, additional amorphous molybdenum-containing material 513b is slowly deposited using a suitable deposition method, such as ALD with MoCh, to a thickness below the critical thickness for crystallization. At operation 503, local changes to the film surface are induced (referred to in the figure as fluctuation of the film surface 513c) in regions of the film that are thicker than a critical thickness of crystallization. At operation 504, local crystallization in the molybdenum-containing material begins, forming a molybdenum crystallites 17 separated by regions of amorphous molybdenum- containing material 518. The regions of amorphous molybdenum-containing material 518 have a thickness below critical thickness for crystallization. At operation 505, amorphous molybdenum- containing material 518 is further deposited on the film surface, where the grow th of the amorphous molybdenum-containing material is slow, to prevent triggering additional crystallization. At operation 506, molybdenum crystallites 517a continue to grow, absorbing the amorphous molybdenum-containing material 518 between the crystallites. Initial crystallites may continue to grow until terminated by another crystallite to form long horizontal grains of molybdenum, without introducing additional nucleation of crystallites. At operation 507, the top surface of the substrate (and molybdenum crystallites thereon) 517b is etched. During operation 507, the amorphous molybdenum-containing material on the surface of, and / or between the regions of molybdenum crystallites may also be etched. This etching may also remove defective crystallite grains and / or segregated impurities. At operation 507, molybdenum crystallites are also etched, reducing their thickness. Then at operation 508, molybdenum is deposited and recrystallized rapidly 519 This is performed at high temperatures, e.g., 450 °C.

[0109] In this example, the resulting molybdenum film does not contain, or only minimally contain, seams between the molybdenum cry stallite grain boundaries.

[0110] In some embodiments, operations 501-507 in Figure 5 are performed at low temperature (350 °C to 450 °C) while operation 508 is performed at a higher temperature. In some embodiments, each operation 501 to 508is, independently, between about 325 °C and 375 °C, between 350 °C and 450 °C, or between 300 °C and 500 °C. In some embodiments, all operations 501 to 508 are performed at the same temperature.

[0111] In some embodiments, operations 501-507 are performed in the same station or chamber in an apparatus or a system. In some embodiments, operation 508 is performed in the second, third, and fourth station or chamber, different from the stations used in operations 501-507.

[0112] Figure 6 illustrates the second example of process 400, similar to the first example in Figure 5 performed without operation 507, i.e., etching of the top surface of the substrate and molybdenum crystallites removing the amorphous molybdenum-containing material on the surface of, and / or between the regions of molybdenum cry stallites.

[0113] In this example, the resulting molybdenum film may not contain, or minimally contain, seams between the molybdenum crystallite grain boundaries. The resulting molybdenum film may contain impurities and include a larger contribution of slowly grown molybdenum crystallites compared to the example in Figure 5. Growing molybdenum film by the example operation in Figure 6 may be faster than the example operation in Figure 5.

[0114] Figure 7 illustrates a third example of process 400. without performing operations 505 and 506 in the Figure 5. In this example, the resulting molybdenum film may contain seams between the molybdenum cry stallite 519 grain boundaries. The resulting molybdenum film may not, or minimally contain impurities, and contain relatively small contribution of slowly grown molybdenum crystallites compared to the example in Figures 5 or 6. The slowly grown molybdenum crystallites may be separated, without being terminating by another crystallite.

[0115] Figure 8 illustrates the fourth example of process 400, similar to the first example in Figure 5 where the slow growth initial crystallite is stopped prior to being terminated by another crystallite, as depicted by molybdenum cry stallite 527a in 506a .

[0116] In this example, the resulting molybdenum film 527b and 519 may not contain, or minimally contain, seams between the molybdenum crystallite grain boundaries. The resulting molybdenum film 527b and 519 may not, or minimally contain impurities, and contain relatively small contribution of slowly grown molybdenum crystallites 527b. The slowly grown molybdenum crystallites 527b may be separated, without being terminated by another crystallite.

[0117] Figure 9 illustrates the fifth example of process 400, similar to the first example in Figure 5 but a high dose of MoCU is used during operations 505 and 506. In this example, the deposition of amorphous molybdenum-containing material and growth of molybdenum crystallites is accompanied by zero net growth of amorphous molybdenum-containing material. The high doseof MoCh may be selected for ALD, where amorphous molybdenum-containing material 518 is etched at a faster rate than the crystalline molybdenum 517 and 517a.

[0118] In this example, the potential for extra nucleation of molybdenum crystallite is reduced, or even eliminated. Under such circumstances, an initial molybdenum cry stallite 517 may continue to grow until terminated by another molybdenum crystallite 517a without additional nucleation.

[0119] In this example, the resulting molybdenum film 517b and 519 may not contain, or minimally contain, seams between the molybdenum crystallite grain boundaries. The resulting molybdenum film 517b and 519 may not, or minimally contain impurities, and contain relatively small contribution of slowly grown molybdenum crystallites 517b. The method illustrated in Figure 9 may have better gap-fill properties. The method illustrated in Figure 9 may be performed at a large range of temperatures.

[0120] Figure 10 illustrates another sixth example of process 400, similar to the example provided in Figure 6 but with a high dose of M0CI4 used during operations 505 and 506. Similar to the example in Figure 9, the deposition of amorphous molybdenum-containing material 518 and growth of molybdenum crystallites 517a is accompanied by zero net growth of amorphous molybdenum-containing material 518.

[0121] In this example, the resulting molybdenum film 517b and 519 may not contain, or minimally contain, seams between the molybdenum crystallite grain boundaries. The resulting molybdenum film 517b and 519 may not, or minimally contain impurities, and contain relatively small contribution of slowly grown molybdenum crystallites 517b. The method illustrated in Figure 10 may have better gap-fill properties. The method illustrated in Figure 10 may be performed at a large range of temperatures.

[0122] In some embodiments, the methods may be used for bottom-up deposition of Mo in a feature. Bottom-up deposition refers to grow th that is mostly or wholly from a feature bottom relative to the feature sidewalls. Using conventional deposition methods to fill features can result in nucleation and growth on all feature surfaces, for example, as illustrated in Figure 1A. 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 pinch off the feature. A seam can form in the center of a feature as the film grows inward from the sidewalls. Bottom-up deposition can avoid the formation of voids and seams in the feature during the filling process.

[0123] In some embodiments, the bottom-up Mo deposition methods may produce molybdenum gap-fill with a reduced number of crystallite grains inside a feature, nearly a single crystalline domain, or even a single crystal inside a feature.

[0124] In some embodiment, the method descnbed herein may be used to selectively deposit molybdenum crystallite having orientations, Mo (100), Mo (111), or Mo (110), depending on the dosage of molybdenum-containing precursor.

[0125] Figure 11 is a process flow diagram illustrating example operations in a method for bottom- up deposition of molybdenum inside a feature. Process 1100 begins with operation 1101, in which a feature in a substrate having a layer of amorphous molybdenum-containing material at the feature bottom is provided. In operation 1103, local crystallization is induced in molybdenum-containing material to form, at the feature bottom, molybdenum crystallites. After operation 1103, molybdenum crystallites at the feature bottom may be separated by regions of amorphous molybdenum-containing material, where each crystallite is, independently, a Mo (100), Mo (11 1), or Mo (110) orientation. In operation 1105, one or more molybdenum crystallites are etched, leaving at least one molybdenum cry stallite at the feature bottom. In operation 1105, molybdenum crystallite may be etched by exposing the substrate to a molybdenum chloride precursor. In operation 1 107, the remaining molybdenum crystallite or crystallites are grown to fill the feature.

[0126] Referring to operation 1101, a feature in a substrate having a layer of amorphous molybdenum-containing material at the feature bottom may be formed by first providing a substrate having a feature and forming a layer of molybdenum liner along and covering the feature sidewalls, feature bottom, and the feature fields adjacent to the feature opening. In some embodiments, the molybdenum liner layer may be an amorphous molybdenum-containing material. The layer of molybdenum liner covering the feature may be exposed to a high dose of MoCls. Exposure to a high dose of MoCb may remove the layer of molybdenum liner from the feature sidewalls, and feature fields, leaving a layer of molybdenum layer on the feature bottom. In some embodiments, some molybdenum layer may be present on feature sidewalls near the feature bottom. This is due to differences in concentration of Mods on the feature fields and / or near the feature opening compared to the feature bottom due to diffusion limitations. For example, there may be a higher concentration of MoCh at the feature fields and / or near the feature openings compared to the feature bottom. This translates to different etch rates, for example, the bottom of the feature may experience a lower etch rate, and the feature fields and / or near the feature opening may experience a high etch rate.

[0127] As noted above, in operation 1103, local crystallization in the molybdenum-containing material is induced, forming molybdenum crystallites separated by regions of amorphous molybdenum-containing material. In some embodiments, each molybdenum crystallite is, independently, a Mo (100), Mo (111), or Mo (110) orientation.

[0128] In various embodiments, operation 1103 may be performed according to operation 400 outlined in Figure 4. In operation 1103, molybdenum-containing material is slowly grown fromthe feature bottom, until it begins to crystallize. During this operation, one or more crystallite grains may form. In some embodiments, one or more crystallites may have one or more different orientations on the top facet, and orientation of cr stallite may be independent of one another.

[0129] In operation 1105, one or more molybdenum crystallites are etched, leaving at least one molybdenum crystallite at the feature bottom. In some embodiments, etching one or more molybdenum crystallites involves exposing the substrate to a molybdenum chloride precursor, e.g., Mods, leaving at least one molybdenum crystallite remaining at the feature bottom. In some embodiments, operation 1105 may leave one molybdenum crystallite remaining at the feature bottom.

[0130] Depending on the concentration of the MoCh precursor, one or more crystalline orientations may be etched. The etch rate of molybdenum crystallite may be tuned such that different orientations of molybdenum face different etch rates. This is due to the difference in etching and growth contribution in each molybdenum crystallite. This behavior is illustrated in Figure 13 and further described below. At moderate to high doses of MoCh. the etch rate increases from Mo (110) to Mo ( 100) to Mo (1 1 1). At moderate to high doses of MoCh, the net growth rate of Mo (110) is highest, while Mo (111) is the lowest, and Mo (100) is between the net growth rate of Mo (110) and Mo (100). At moderate to high doses of M0CI5, the etch rate increases from Mo (110) to Mo (100) to Mo (111). This behavior is accentuated as the dose of M0CI5 is increased.

[0131] In some embodiments, depending on the duration of exposure and concentration of M0CI5, one or more crystallite orientations may remain at the feature bottom. In some embodiments, depending on the duration of exposure and concentration of Mods, only one orientation of molybdenum crystalline may remain at the feature bottom. In some embodiments, depending on the duration of exposure and concentration of Mods, only a single molybdenum crystallite may remain at the bottom of the feature. For example, at very high doses of M0CI5, molybdenum facets with 111 and / or 100 will etch away faster than 110, leaving molybdenum crystallites in the feature bottom. A very high dose of MoCh may be less than 0. 1 A per cycle or about 0.05 A per cycle. In some embodiments, very high dose of M0CI5 is 5-15% higher than the high dose.

[0132] Operation 1105 may enlarge specific molybdenum orientations while consuming other molybdenum orientations.

[0133] In some embodiments, the concentration of M0CI5 is selected such that molybdenum facets with 111 and / or 100 will etch away, while molybdenum facets with 110 are being deposited. The dose of M0CI5 may be very high in this case. In some embodiments, molybdenum crystallites with 110 orientations may further grow until terminated by another molybdenum crys tai lite with 110 orientations.

[0134] In some embodiments, the dose of MoCh is changed once crystallites wi th a single orientation, or a single orientation, e.g., Mo (110) remains at the feature bottom. In some embodiments, the dose of MoCh is not changed once crystallites with a single orientation, or a single orientation, e.g., Mo (110) remains at the feature bottom.

[0135] In operation 1107, molybdenum is deposited to grow the remaining crystallite(s) at the feature bottom.

[0136] In some embodiments, when a single molybdenum crystallite, or a molybdenum crystallite with single orientation remains at the bottom of the feature, molybdenum may be further deposited to fill the gap by any suitable deposition method, for example, thermal atomic layer deposition (ALD), atomic layer deposition with MOO2CI2 with or without a reducing agent (e.g., H2), or atomic layer deposition with any other suitable molybdenum-containing precursor, plasma enhanced ALD (PEALD), plasma enhanced chemical vapor deposition (PECVD) with suitable molybdenum-containing precursors such as MOO2CI2 and / or MoCh with a reducing agent (e.g., H2) plasma.

[0137] Figure 12 provides a schematic illustration of the process 1100. In Figure 12, referring to 1201, the process begins with providing a featured substrate 1221; and referring to 1203, forming a layer of molybdenum liner 1222a along and covering the feature sidewalls, feature bottom, and the feature fields adjacent to the feature openings over the featured substrate 1221. Referring to 1205, the layer of molybdenum liner 1222a is removed from the feature sidewalls, and feature fields, leaving a layer of molybdenum layer 122b on the feature bottom. In 1207, local crystallization in molybdenum liner forms molybdenum crystallites at the feature bottom separated by regions of amorphous molybdenum-containing material. 1207 is depicted to have two molybdenum crystallites with Mo (1 10) 1217a and Mo (111) 1217b at the feature bottom, but one or more crystallites and molybdenum crystallite orientations can be present at this point. One or more molybdenum cry stallites in 1207 are etched, leaving at least one molybdenum crystallite at the feature bottom. For example, the molybdenum crystallites Mo (111) 1217b in 1207 were etched, thereby leaving Mo (110) 1217a crystallites, as depicted in 1209. The remaining molybdenum crystallite 1217a in 1209 is then grown to fill the featurel227a, as depicted in 121 1.

[0138] Process 1100 may be practiced without some of the operations disclosed. For example, Process 1100 may be performed without operation 1105. The sequence 1207 to 1209 and 1211 is referred to as Branch 1 in Figure 12. Other sequences are also possible, as shown in the Figure. For example, after 1207, i.e., forming molybdenum crystallites in the molybdenum liner 1217a and 1217b at the feature bottom, the crystallites may be grown to fill the feature via low-dose ALD with M0CI5. This results in bottom-up feature fill of molybdenum crystallites 1213a and 1213b, where all or nearly all molybdenum crystallites 1213a and 1213b are growing at a similar netgrowth rate. The resulting molybdenum fill 1213a and 1213b of the feature may contain seams between crystallites, as depicted in 1213.

[0139] In another example, after 1207, molybdenum cry stallite may be grown to fill feature by high dose ALD with MoCb. This results in bottom-up feature fill of molybdenum crystallites, where certain molybdenum crystallite orientations may growt at afaster rate, i.e., net growth rate Mo (110) > Mo (100) > Mo (11 1). The details on the molybdenum net growth rate for each crystallite orientation is provided below. The resulting molybdenum fill may be nearly a single grain 1215a gap-fill across the feature; however, it may contain an early termination of certain molybdenum grain 1215b which may be present near the bottom of the feature, as depicted in 1215.Molybdenum Deposition

[0140] In the methods described herein, molybdenum deposition may be performed after the treatments described above with reference to Figures 13-15. Deposition of molybdenum as described herein involves reacting a Mo-containing precursor, also referred to as a molybdenum precursor. 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 used for deposition.

[0141] In some embodiments, a Mo precursor is a molybdenum chloride (MoClx) compound also referred to as a molybdenum chloride precursor or MoClx precursor. For example, operations 1307 and / or 1309 in Figure 13, operation 1403 in Figure 14, or operation 1515 in Figure 15 may use a molybdenum oxyhalide precursor. Molybdenum chloride precursors are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (MoCh), molybdenum trichloride (MoCh), molybdenum tetrachloride (MoCh). molybdenum pentachloride (MoCb), and molybdenum hexachloride (Mode). In some embodiments, MoCb or MoCb are used. While the description chiefly refers to MoClx precursors, 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 MoXz precursors include molybdenum fluoride (MoFe). In some embodiments, a non-fluorine-containing MoXz precursor is used to prevent fluorine etch or incorporation. In some embodiments, a non-bromine-containing and / or a non- iodine-containing MoXz precursor is used to prevent etch or bromine or iodine incorporation.

[0142] In some embodiments, the feature may be filled using a molybdenum oxyhalide precursor. For example, operations 1307 and / or 1309 in Figure 13, operation 1403 in Figure 14,or operation 1515 in Figure 15 may use 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 MoOyXz forms a stable compound. Examples of molybdenum oxyhalides include molybdenum dichloride dioxide (MOO2CI2). molybdenum tetrachloride oxide (MoOCh), molybdenum tetrafluoride oxide (MoOF4), molybdenum dibromide dioxide (MoChBn), 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 MoClx precursor, MoOyXz precursor, or a combination thereof.

[0143] 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 (SiFE), diborane (B2H6), germane (GeEU), ammonia (NHs), and hydrazine (N2H4).

[0144] In some embodiments, deposition of molybdenum may use a plasma-based process. 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, nitrogencontaining gas, such as nitrogen (N2) and other gases, such as Ar and NHs. The plasma species may be inert or react with the molybdenum precursor to form a film.

[0145] 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.

[0146] 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 an initial molybdenum layer (e g., as in operation 1305 or 1307 of Figure 13), M0CI5 may be used as a precursor and H2 as a reducing agent. Doses of M0CI5 and H2 are 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 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, theT1temperature and / or pressure may be used to control selectivity.

[0147] 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.

[0148] 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.

[0149] 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 grow th may be easier on a metal material relative to molybdenum deposition and growth on a dielectric material. For example, a feature may have a sidewall surface of SiCh and a TiN plug in a bottom portion of the feature. In selective deposition, molybdenum is deposited into the feature and may grow- on the TiN plug but not grow (or grow to a lesser extent) on the SiCh sidewall surfaces.

[0150] Process 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. Different precursor gases may have different process windows in which molybdenum film may be selectively deposited. Generally speaking, M0CI5 gas 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 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. For example, at higher temperatures, a precursor gas such as M0CI5 may lose its selectivity7and deposit molybdenum film on both a metal surface and a dielectric surface within a feature.

[0151] M0CI5 may be reacted with different reactant to deposit a molybdenum film. Described below are examples of deposition of molybdenum 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 metalprecursors are reacted with hydrogen (H2) as a co-reactant (also referred to as a hydrogen reactant or H2 reactant). However, other reactants may be used instead of hydrogen including other hydrogen-containing reactants such SiH4, B2H6, NH3, as appropriate. While reactants such as B2H6 and / or Si Hr are stronger reducing agents, they can also result in higher resistivity . Thus, in some embodiments, using H2 as described herein is advantageous. 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 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 using the M0CI5 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.

[0152] In some embodiments, selective deposition is performed using a molybdenum oxyhalide precursor. As described above, the surface treatments described above significantly improve selectivity of Mo deposition from MOO2CI2. As indicated above, examples of MoOyXz precursors include MOO2CI2, MoOCh, MoOF4, MoChBn, 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 MoClx precursor used in the surface treatment. For example, a MoOyXzprecursor may deposit molybdenum at a deposition rate at least twice as fast as a MoClx precursor for a non-plasma process. Plasma enhanced processes may be used to fill features at lower temperatures and / or increase deposition rates.

[0153] In some embodiments, filling a feature can involve depositing a nucleation layer. A nucleation layer is a thin layer that 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., B2H6) or a silicon-containing reducing agent (e.g., SiH4) 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 / Morefers 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 (B2H6), alkyl boranes, alkyl boron, aminoboranes (CH3)2NB(CH2)2, 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 sili con-containing reducing agents including silane (Sikh) and other silanes such as disilane (Si2He).

[0154] In some embodiments, deposition of a Mo nucleation layer may involve using a non- oxygen-containing precursor, e.g., molybdenum hexafluoride (MoFe) or molybdenum pentachloride (M0CI5). Oxygen in oxygen-containmg precursors may react with a silicon- or boron-containing reducing agent to form MoSixOy or 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).

[0155] In some embodiments, H2 may be used as a reducing gas for Mo nucleation layer deposition instead of a boron-containing or silicon-containing reducing gas. Example thicknesses 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.

[0156] 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 SiEU (or other boron- or silicon-containing reducing agent) pulse may be performed at a temperature below 300°C, with the Mo pulse at temperatures greater than 300°C.

[0157] In some embodiments, the reducing agent is NH3 or 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 NH3 and metal oxychloride or metal chloride precursors, nucleation delay is reduced or eliminated at deposition temperatures up to hundreds of degrees low er than used by H2 reduction of the same metal precursors.

[0158] In some embodiments, the reducing agent may be a boron-containing or silicon-containing reducing agent such as B2H6 or SiH4. These reducing agents may be used with metal chloride precursors, with metal oxychlorides; however, the B2H6 and SiH4 may react with water formed as a byproduct during the ALD process and form solid B2O3 and SiCh. These are insulating and can remain in the film, increasing resistivity. Use of NH3 also has improved adhesion over B2H6 and SiH4 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 a 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.

[0159] The etching and growth component / rate of molybdenum-containing material may be controlled by selecting an appropriate dosage. The M0CI5 may be used to etch and / or deposit molybdenum-containing material, depending on the doses used. Figure 16 illustrates the interplay of growth (dashed lines) and etch (dotted lines) components in M0CI5, and the net effect (solid lines) for different crystalline phases of molybdenum, i.e.. Mo (110), Mo (100), and Mo (11 1). Referring to Figure 13, the growth component (dashed lines) for Mo (110), Mo (100), and Mo (111) increase as the dose of M0CI5 increases, until a certain point of saturation / thickness, as the ALD growth process is a self-limiting reaction. The etch component is nearly absent in low- doses of M0CI5, but increasing the dose generally increases the etch component. Growth and etching components may be differently affected in each crystalline phase.

[0160] A low dose of M0CI5 refers to a regime where M0CI5 contributes primarily to growth components with an absence or near absence of etching, leading to net growth of molybdenum- containing material. In the low-dose regime, increasing doses of M0CI5 generally increase the growth component, i.e., rate, of the molybdenum-containing material. A moderate dose of M0CI5 refers to a dosage where both etching and growth components may be present, however, the etching component is not high, leading to net growth of molybdenum-containing material. In the ‘moderate’-dose regime, increasing doses of M0CI5 generally increase the growth component, i.e.,rate, of the molybdenum-containing material. Compared to a low-dose regime 'moderate’ dose regime of MoCh may have a high growth rate. A high dose of MoCh refers to a dosage where both etch and grow th components may be prominent.

[0161] A high dose of Mods refers to a dosage where both etch, and growth components may be present. The high-dose regime may include a substantial etching component and depending on the dosage and the crystalline phases of molybdenum, the process may be tuned to promote net positive growth or net negative growth of the molybdenum-containing material. In a high-dose regime, Mods may etch away defective regions of Mo cry stallite grain boundaries and / or defective surfaces purifying the crystalline structure of the Mo grains and may prevent intercalation of the impurities in the body of the crystallite. In some embodiments, surface irregularities may be eliminated. In some embodiments, high-dose M0CI5 may etch defective surfaces at a faster rate than molybdenum cry stallites. In various implementations, the high-dose process may be characterized as a process, e.g., ALD, where the molybdenum-containing precursor dose is 8 times or more compared to a low-dose process.

[0162] In various embodiments, amorphous molybdenum-containing material may be etched faster than molybdenum crystallites.

[0163] Depending on the cry stalline orientation, etching and growth components may be further controlled by selecting an appropriate dosage. As shown in Figure 13, at low doses of MoCE, the growth component of three molybdenum crystallite orientations is similar, with the absence or near absence of etching, leading to net growth in all three molybdenum orientations at a similar rate. In the low-dose regime, increasing doses of M0CI5 generally increase the net growth component in all three orientations in a similar matter.

[0164] At higher doses of MoCE, growth and etch contributions in each Mo (110), Mo (100), and Mo (111) start to deviate and may lead to preferential growth or etching of one orientation over another depending on the choice of M0CI5 dose. At high doses, growth component of the molybdenum crystallites increases from Mo (111), Mo (100), to Mo (110). At high doses, etch component of the molybdenum crystallites increases from Mo (110). Mo (100), to Mo (111). At certain high doses of M0CI5, Mo (111) and Mo (100) may experience net negative growth, while Mo (110) may experience net positive growth. Resulting effect may be a selective growth of Mo (110) orientation over other orientations.Etch

[0165] Etch operations may7be used in the methods for filling features with Mo films. Etch operations remove materials such as metals and nitrides from the feature. For example, an etch process may partially or completely remove a liner layer from a feature. In another example, theetch process may be used to reduce the thickness of a liner layer. The etch operation, in some embodiments, may involve soaking the feature soaked in a Mo halide. In some embodiments, an etch operation involves soaking the feature with a MoClx such as M0CI5. In some embodiments, the soak may be done continuously with the Mo halide gas. In some embodiments, the soak may be pulsed, cycling the Mo halide with a purge gas, such as argon (Ar).

[0166] A MoClx precursor may be used for both deposition and etch operations. For example, in certain process windows, a M0CI5 precursor may concurrently grow a Mo film and etch away a metal or metal compound film in the feature. The process is considered a net etch operation if the rate of material removed is greater than the material deposited by the precursor. The speed at which the precursor deposits material and etches material may be controlled by a variety of process conditions, including the type of reactant used and the process temperature. Generally speaking, the lower the temperature, the higher the ratio of etching away material is relative to deposition of material. At higher temperatures, the same precursor and reactant may be used as a net deposition operation, i. e. , the amount of material deposited is greater than the material removed. F or example, M0CI5 precursor and H2 reactant may be used in an etch operation when the process temperature is below 400°C. The same precursor of M0CI5 and H2 reactant may be used in a deposition operation when the process temperature is above 550°C.

[0167] In some embodiments, the MoClx precursor at high temperatures, e.g., above 550°C. may continue to etch material at a faster rate than depositing material. For example, M0CI5 may be used to etch a feature by a soak without a reactant. In this example, the temperature may be as high as 700°C and will continue to etch away material from the feature. In operations where the feature is soaked in a M0CI5 without a reactant, the increased temperature may increase the rate at which material is etched from the feature.

[0168] A feature may have surface oxide or contaminants on it. For example, the surface of an underlying TiN, WN, or W layer may be oxidized. If left, the oxidized surface can result in higher resistivity. Clean operations are used to remove such oxides and contaminants. In some embodiments, the clean operation may have the feature soaked in a Mo precursor gas, typically a Mo halide. Similar to the etch operations described above, the precursor gas may be a MoClx precursor. In some embodiments, the soak may be done continuously. In some embodiments, the soak may be pulsed, cycling MoClx and a purge gas, such as argon (Ar). The precursor may be a non-oxygen Cl-containing Mo compound able to remove oxidation from the feature's surfaces. Examples of MoClx compounds are given above. A Cl-containing precursor may be used where traditional cleaning with thermal or plasma H2 does not work, such as where the oxidized surface is stable on the surface material. A Cl-containing precursor is less likely to over-etch a feature’s liner layer or attack a feature’s surfaces than a F-containing compound.Apparatus

[0001] Figure 17 depicts a schematic illustration of an embodiment of an ALD process station 1700 having a process chamber 1702 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, Figures 18A and 18B depict embodiments of a multi-station processing tool 1800. In some embodiments, one or more hardware parameters of ALD process station 1700, including those discussed in detail below, may be adjusted programmatically by one or more computer controllers 1850. In some other embodiments, a process chamber may be a single station chamber.

[0002] ALD process station 1700 fluidly communicates with reactant delivery system 1701a for delivering process gases to a distribution showerhead 1706. Reactant delivery system 1701a includes a mixing vessel 1704 for blending and / or conditioning process gases, such as a Mo precursor-containing gas, a hydrogen-containmg gas, an argon or other carrier gas, or other reactant-containing gas, for delivery to showerhead 1706. One or more mixing vessel inlet valves 1720 may control introduction of process gases to mixing vessel 1704. In various embodiments, deposition of an initial Mo layer is performed in process station 1700 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 1800 as further described below w ith respect to Figure 18 A.

[0003] As an example, the embodiment of Figure 17 includes a vaporization point 1703 for vaporizing liquid reactant to be supplied to the mixing vessel 1704. In some embodiments, vaporization point 1703 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 1704. In one embodiment, a liquid injector may vaporize the reactant by flashing the liquid from ahigher 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 1703. In one scenario, a liquid injector may be mounted directly to mixing vessel 1704. In another scenario, a liquid injector may be mounted directly to showerhead 1706.

[0004] In some embodiments, a liquid flow controller (LFC) upstream of vaporization point 1703 may be provided for controlling a mass flow of liquid for vaporization and delivery to process chamber 1702. 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.

[0005] Showerhead 1706 distributes process gases toward substrate 1712. In the embodiment shown in Figure 17, the substrate 1712 is located beneath showerhead 1706 and is shown resting on a pedestal 1708. Showerhead 1706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to substrate.

[0006] In some embodiments, pedestal 1708 may be raised or lowered to expose substrate 1712 to a volume between the substrate 1712 and the showerhead 1706. In some embodiments, pedestal 1708 may be temperature controlled via heater 1710. Pedestal 1708 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. At the conclusion of a process phase, pedestal 1708 may be lowered during another substrate transfer phase to allow removal of substrate 1712 from pedestal 1708.

[0007] In some embodiments, a position of showerhead 1706 may be adjusted relative to pedestal 1708 to vary a volume betw een the substrate 1712 and the showerhead 1706. Further, it will be appreciated that a vertical position of pedestal 1708 and / or showerhead 1706 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, pedestal 1708 may include a rotational axis for rotating an orientation of substrate 1712. 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 1750. The computer controller 1750 may include any of the features described below with respect to controller 1750 of Figure 17.

[0008] In some embodiments where plasma may be used as discussed above, showerhead 1706 and pedestal 1708 electrically communicate with a radio frequency (RF) power supply 1714 and matching netw ork 1716 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 1714 and matching network 1716 may be operated at any suitable power to form a plasmahaving a desired composition of radical species. Likewise. RF power supply 1714 may provide RF power of any suitable frequency. In some embodiments, RF power supply 1714 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.

[0009] 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.

[0010] In some embodiments, instructions for a controller 1750 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 a 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 ofan inert and / or a reactant gas, and instructions for modulating a flow rate of a earner 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.

[0011] Further, in some embodiments, pressure control for process station 1700 may be provided by butterfly valve 1718. As shown in the embodiment of Figure 17, butterfly valve 1718 throttles a vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of process station 1700 may also be adjusted by varying a flow rate of one or more gases introduced to the process station 1700.

[0012] Figure 18A and Figure 18B show' examples of processing systems. Figure 18A shows an example of a processing system including multiple chambers. The system 1800 includes a transfer module 1803. The transfer module 1803 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 1803 is a multi-station chamber 1809 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.

[0013] Chamber 1809 may include multiple stations 1811, 1813, 1815, and 1817 that may sequentially perform operations in accordance with disclosed embodiments. For example, chamber 1809 may be configured such that station 1811 performs an in-situ treatment using a MoCk precursor. Station 1813 may be configured to selectively treat the field region and upper sidew alls and stations 1815 and 1817 may be configured to perform ALD of bulk Mo using an molybdenum oxyhalide precursor and H2. In another example, chamber 1809 may be configured such that station 181 1 performs in-situ clean, station 1813 performs ALD of an initial Mo layer, station 1813 selectively treats the layer, and 1814 deposition of bulk Mo. In another example, the chamber 1809 may be configured to do parallel processing of substrates, with each station performing multiple processes sequentially.

[0014] 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.

[0015] Also mounted on the transfer module 1803 may be one or more single or multi-stationmodules 1807. In some embodiments, a preclean as described above may be performed in a module 1807, after which the substrate is transferred under vacuum to another module (e.g., another module 1807 or chamber 1809) for ALD. In another example, a module for selective treatment of a film may be mounted on the transfer module.

[0016] The system 1800 also includes one or more wafer source modules 1801, where wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 1819 may first remove wafers from the source modules 1801 to loadlocks 1821. A wafer transfer device (generally a robot arm unit) in the transfer module 1803 moves the wafers from loadlocks 1821 to and among the modules mounted on the transfer module 1803.

[0017] In some embodiments, ALD of Mo is performed in a first chamber, which may be part of a system like system 1800, with CVD or PVD of W or Mo or other conductive material deposited as an overburden layer performed in another chamber, which may not be coupled to a common transfer module, but part of another system.

[0018] Figure 18B is an embodiment of a system 1800. The system 1800 in Figure 18B has wafer source modules 1801, a transfer module 1803, atmospheric transfer chamber 1819, and loadlocks 1821, as described above with reference to Figure 18 A. The system in Figure 18B has three single station modules 1857a-17875c. The system 1800 may be configured to sequentially perform operations in accordance with disclosed embodiments. For example, the single station modules 1857a-1857c may be configured so that a first module 1857a performs a surface treatment, a second module 1857b performs ALD of an initial Mo layer using a molybdenum halide precursor, and a third module 1857c performs ALD of bulk Mo using a molybdenum oxyhalide precursor. In this example, an in-situ clean may be optionally performed in second module 1857b instead of or in addition to a preclean in first module 1857a. In another example, the single station modules 1857a-l 857c may be configured so that a first module 1857a performs a deposition of an initial metal layer, a second module 1857b performs selective treatment, and a third module 1857c 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.

[0019] 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 17.

[0020] Referring to Figures 18A and 18B, in various embodiments, a system controller 1829 is employed to control process conditions during deposition. The controller 1829 will typically include one or more memory' devices and one or more processors. A processor may include a CPUor 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.

[0021] The controller 1829 may control all the activities of the apparatus. The system controller 1829 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 1829 may be employed in some embodiments.

[0022] Typically, there will be a user interface associated with the controller 1829. The user interface may include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 1829. The signals for controlling the process are output on the analog and digital output connections of the deposition apparatus.

[0027] 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.

[0028] In some implementations, a controller 1829 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 flow7system, etc.). These systems 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 1829, 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 delivery7settings, positional and operation settings, yvafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.

[0029] 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 w afer.

[0030] The controller 1829, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combinationthereof. For example, the controller 1829 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 cunent 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 are 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 ty pe of process to be performed and the ty pe of tool that the controller is configured to interface with or control. Thus, as described above, the controller maybe 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.

[0031] Without limitation, example sy stems 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.

[0032] 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.

[0033] The controller 1829 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 chambersuch 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 may control delivery of a heat transfer gas such as helium to the wafer chuck.

[0034] 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 or chuck. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain desired process conditions.

[0035] 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.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: providing a substrate having a layer of amorphous molybdenum-containing material thereon; inducing local crystallization in the layer of amorphous molybdenum-containing material to form molybdenum crystallites separated by regions of amorphous molybdenum- containing material; and exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing material and grow the molybdenum crystallites.

2. The method of claim I . further comprises growing the amorphous molybdenum- containing material to a thickness of no more than 10 Angstroms.

3. The method of claim 1, wherein inducing local crystallization comprises exposing the layer of amorphous molybdenum-containing material to a plasma.

4. The method of claim 1 , wherein inducing local crystallization comprises exposing the layer of molybdenum-containing material to a temperature between 300 °C and 500 °C.

5. The method of claim 1, wherein exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing material and grow the molybdenum crystallites comprises a first operation of exposing the substrate to a molybdenum chloride precursor without a reducing agent to etch without forming molybdenum and a second operation of exposing the substrate to a molybdenum halide precursor and a reducing agent to deposit molybdenum.

6. The method of claim 5, wherein the second operation comprises an atomic layer deposition process.

7. The method of claim 1 , wherein exposing the substrate to a molybdenum chloride precursor to etch at least a portion of the amorphous molybdenum-containing materialand grow the molybdenum crystallite comprises an atomic layer deposition process using a molybdenum chloride and reducing agent.

8. The method of claim 1, wherein the molybdenum chloride precursor is M0CI5.

9. A method comprising:(a) providing a feature in a substrate, wherein the feature has a feature bottom and wherein there is a layer of amorphous molybdenum-containing material at the feature bottom;(b) inducing local crystallization in the layer of molybdenum-containing material to form, at the feature bottom, molybdenum crystallites separated by regions of amorphous molybdenum-containing material, wherein each crystallite, independently, has a Mo (100). Mo (111), or Mo (110) orientation;(c) exposing the substrate to a molybdenum chloride precursor to etch one or more crystallites, leaving exactly one cry stallite at the feature bottom; and(d) growing the remaining crystallite to form a single-grain layer at the feature bottom.

10. The method of claim 9, wherein (c) etches at least one of Mo (111) and Mo (100) orientations.

11. The method of claim 9, wherein the single-grain layer in (d) comprises the Mo (110) orientation.

12. The method of claim 9, wherein the molybdenum chloride precursor is M0CI5.

13. The method of claim 9, further comprising growing the amorphous molybdenum- containing material to a thickness of no more than 10 Angstroms.

14. The method of claim 9, wherein inducing local crystallization comprises exposing the layer of amorphous moly bdenum-containing material to a plasma.

15. The method of claim 9, wherein inducing local crystallization comprises exposing the layer of molybdenum-containing material to a temperature between 300 °C and 500 °C.

16. The method of claim 9. wherein (d) comprises exposing the substrate to a molybdenum chloride precursor.

17. The method of claim 9. wherein (d) exposing the substrate to a very high dose of Mods.

18. The method of claim 9, further comprising (e) exposing the feature bottom to a molybdenum halide precursor and a reducing agent to deposit molybdenum in the feature.

19. The method of claim 18, wherein, the molybdenum deposited in the feature comprises a single grain Mo (110).

20. The method of claim 18, wherein (e) comprises an atomic layer deposition process.

21. A method comprising:(a) providing a feature in a substrate, wherein the feature has a feature bottom and wherein there is a layer of amorphous molybdenum-containing material at the feature bottom;(b) inducing local crystallization in the layer of molybdenum-containing material to form, at the feature bottom, molybdenum crystallites separated by regions of amorphous molybdenum-containing material, wherein each crystallite, independently, has a Mo (100). Mo (111), or Mo (110) orientation;(c) exposing the substrate to a molybdenum chloride precursor to etch one or more crystallites; and(d) growing remaining crystallites to form a layer at the feature bottom.

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