TW201715067A - Deposition of low fluorine tungsten by sequential CVD process - Google Patents

Abstract

Provided herein are methods of depositing bulk tungsten by sequential CVD pulses, such as by alternately pulsing tungsten hexafluoride and hydrogen gas in cycles of temporally separated pulses. Some methods include depositing a tungsten nucleation layer at lower pressure followed by deposition of bulk tungsten by sequential CVD to form low stress tungsten films with low fluorine content. Methods described herein may also be performed in combination with non-sequential CVD deposition and fluorine-free tungsten deposition techniques.

Description

Low fluorine content tungsten deposition by sequential chemical vapor deposition process

This invention relates to the deposition of tungsten having a low fluorine content.

The deposition of tungsten-containing materials is an integral part of many semiconductor fabrication processes. These materials can be used for horizontal interconnects, vias between adjacent metal layers, contact windows between the metal and germanium substrates, and high aspect ratio features. In a conventional tungsten deposition process on a semiconductor substrate, the substrate is heated to a processing temperature in a vacuum chamber and deposited as a very thin portion of the tungsten-containing film of the seed layer or nucleation layer. Thereafter, the remaining tungsten film (host layer) is deposited on the nucleation layer by simultaneously exposing the substrate to the two reactants. The deposition of the bulk layer is usually faster than the nucleation layer. However, deposition of thin tungsten films becomes a challenge when patterned and more complex patterned structures are used in the industry.

Methods and apparatus for depositing tungsten are presented herein. A method for filling a feature comprising: (a) exposing a substrate to a reducing agent and an alternating pulse of a tungsten-containing precursor in a chamber to deposit a tungsten nucleation layer on the substrate; and (b) The substrate is exposed to alternating pulses of hydrogen and a tungsten-containing precursor to deposit a bulk tungsten layer on the tungsten nucleation layer, wherein the chamber pressure during step (a) is no greater than 10 Torr.

The method may further comprise: (c) simultaneously exposing the substrate to a reducing agent and a tungsten-containing precursor to deposit a second bulk tungsten layer. The method may further comprise: (d) performing step (c) every two or more cycles of performing step (b), wherein one of the steps (b) comprises a pulse of hydrogen and a pulse of the tungsten-containing precursor.

In various embodiments, step (b) is carried out in a plurality of cycles comprising a pulse of hydrogen and a pulse of the tungsten-containing precursor, each cycle forming a single layer having a thickness of at least about 0.3 Å.

The tungsten-containing precursor in step (a) may be different from the tungsten-containing precursor in step (b). In certain embodiments, the tungsten-containing precursor in step (a) is fluorine-free.

The tensile stress of the deposited tungsten can be less than about 1 GPa per 500 Å of deposition.

Another aspect relates to a method of depositing tungsten on a substrate, comprising: (a) depositing a tungsten layer on the substrate by: (i) exposing the substrate to a reducing agent; and (ii) exposing the substrate To a fluorine-free tungsten-containing precursor; and (b) depositing a bulk tungsten layer in a plurality of cycles comprising: (i) exposing the substrate to hydrogen (H ₂ ); (ii) exposing the substrate to tungsten-containing Precursor; and (iii) repeating steps (i) through (ii) one or more cycles to deposit the bulk tungsten layer.

In certain embodiments, the fluorine-free tungsten-containing precursor is selected from the group consisting of metal-organic tungsten-containing precursors, tungsten chloride, and tungsten hexacarbonyl.

In various embodiments, the fluorine-free tungsten-containing precursor is tungsten hexachloride. In various embodiments, the fluorine-free tungsten-containing precursor is tungsten pentachloride.

The tungsten layer in step (a) can be deposited to a thickness of between about 2 Å and about 100 Å. Each of the cycles in step (b) can form a single layer having a thickness of at least about 0.3 Å.

Another aspect of the method of filling a feature, comprising: (a) exposing a substrate to alternating pulses of hydrogen and a tungsten-containing precursor to deposit a bulk tungsten layer on the substrate; and (b) simultaneously exposing the substrate to A tungsten precursor and a reducing agent are deposited to deposit a second bulk tungsten layer on the substrate.

In various embodiments, steps (a) and (b) are repeated sequentially.

The tungsten-containing precursor in the step (b) may be a fluorine-free tungsten-containing precursor selected from the group consisting of a metal-organic tungsten-containing precursor, a tungsten chloride, and a tungsten hexahydrate. The group that makes up.

In certain embodiments, the tungsten-containing precursor in step (a) is different from the tungsten-containing precursor in step (b).

Another aspect relates to an apparatus for processing a substrate, comprising: (a) at least one processing chamber including a susceptor for supporting a substrate; (b) at least one vent for coupling to a vacuum; (c One or more process gas inlets coupled to one or more process gas sources; and (d) a controller for controlling operation in the apparatus, including machine readable instructions for: (i) Introducing a reducing agent and a tungsten-containing precursor to the processing chamber in an alternating pulse manner; and (ii) introducing hydrogen and a tungsten-containing precursor into the processing chamber in alternating pulses, wherein the chamber during step (i) The pressure is no more than 10 Torr.

Another aspect relates to an apparatus for processing a substrate, the apparatus comprising: (a) at least one processing chamber including a susceptor for supporting a substrate; and (b) at least one vent for coupling to a vacuum; (c) one or more process gas inlets coupled to one or more process gas sources; and (d) a controller for controlling operation in the apparatus, comprising machine readable instructions for: (i Introducing hydrogen and a tungsten-containing precursor to the processing chamber in an alternating pulse to deposit a bulk tungsten layer; and (ii) simultaneously introducing a tungsten-containing precursor and a reducing agent to the processing chamber to deposit a second bulk tungsten Floor. The controller may further comprise machine readable instructions for: sequentially repeating steps (i) and (ii).

These and other aspects will be further described below with reference to the drawings.

In the following description, numerous specific details are set forth. The invention may be practiced without some or all of these specific details. In other instances, well known processing steps will not be described in detail to avoid unnecessarily defocusing the present invention. The invention will be described in conjunction with the specific embodiments, but it should be understood that it is not intended to limit the invention to the embodiments.

Tungsten (W) filling of features is commonly used in the fabrication of semiconductor components to form electrical contacts. Tungsten filling faces various challenges when using smaller technology nodes and component sizes of more complex pattern structures. One challenge is to reduce the concentration or amount of fluorine in the deposited tungsten film. Compared to larger features, smaller features having the same fluorine concentration in the tungsten film as the larger features have a greater impact on the performance of the component. For example, the smaller the features, the thinner the film deposited. Therefore, fluorine in the deposited tungsten film is more likely to diffuse through the thinner film, which may cause component failure.

One method of preventing fluorine diffusion involves depositing one or more barrier layers prior to depositing tungsten to prevent diffusion of fluorine from the tungsten to other layers of the substrate, such as an oxide layer. For example, Figure 1A shows an exemplary stack of layers deposited on a substrate. The substrate 190 includes a germanium layer 192, an oxide layer 194 (eg, titanium oxide (TiOx), tetraethoxydecane (TEOS) oxide, etc.), a barrier layer 196 (eg, titanium nitride (TiN)), tungsten. The nucleation layer 198 and the bulk tungsten layer 199. Barrier layer 196 is deposited to prevent diffusion of fluorine from host tungsten layer 199 and tungsten nucleation layer 198 to the oxide layer. However, as the component shrinks, the barrier layer becomes thinner and fluorine may still diffuse from the deposited tungsten layer. Although bulk tungsten chemical vapor deposition at higher temperatures produces lower fluorine content, such films have poor step coverage.

Another challenge is to reduce the electrical resistance in the deposited tungsten film. Thinner films tend to have higher electrical resistance than thicker films. As the features become smaller, the tungsten contact window or line resistance increases due to the scattering effect in the thinner tungsten film. The low resistivity tungsten film minimizes power loss and overheating in the integrated circuit design. The tungsten nucleation layer typically has a higher resistivity than the upper body layer. Barrier layers deposited in contact windows, vias, and other features may also have high resistivity. In addition, the thin barrier and tungsten nucleation film occupy a larger proportion of the smaller features, increasing the overall resistance of the features. The resistivity of the tungsten film is determined by the thickness of the deposited film, and the resistivity increases as the thickness decreases due to the boundary effect.

Another challenge is to reduce the stress on the deposited film. Thinner tungsten films tend to have greater tensile stress. Conventional techniques for depositing a bulk tungsten film by chemical vapor deposition have a tensile stress greater than 2.5 GPa (for a 200 Å film). The high thermal tensile stress causes curling of the substrate, which causes difficulty in subsequent processing. For example, subsequent processing may include chemical mechanical planarization, deposition of material, and crucible or clamping of the substrate to the substrate support to effect processing in the chamber. However, these processes typically rely on the substrate being flat and the crimped substrate causes non-uniform processing or inability to process the substrate. While there are existing methods to reduce stress in other material films, such as annealing, once tungsten is deposited, it has no surface mobility to allow for grain movement or change due to the high melting point of tungsten.

A method of using a sequential CVD process to deposit a tungsten film having a low fluorine concentration is proposed herein. The deposited film may also have low stress. The method involves introducing hydrogen and a tungsten-containing precursor (eg, tungsten hexafluoride) in a plurality of cycles. The disclosed embodiments can be combined with other tungsten deposition processes to deposit a low stress tungsten film having a substantially lower fluorine content (as compared to deposition by conventional CVD). For example, sequential CVD processing can be combined with nucleation layer deposition at low pressure, deposition of fluorine-free tungsten layers, and non-sequential CVD processing. The disclosed embodiments have a variety of applications. The method can be used to deposit tungsten into the features with high step coverage, and can also be used to deposit tungsten into 3D NAND and vertical NAND structures, including structures with deep trenches.

Sequential CVD processing differs from non-sequential CVD, pulsed CVD, atomic layer deposition (ALD), and nucleation layer deposition. Non-sequential CVD processing involves simultaneous exposure to the two reactants, causing the two reactants to flow simultaneously during deposition. For example, bulk deposition of tungsten may be simultaneously exposed to hydrogen (H ₂₎ and tungsten hexafluoride (WF ₆₎ sufficient to fill one of the features of the substrate by the duration. During the exposure, hydrogen and WF ₆ react to deposit tungsten into the features. In a pulsed CVD process, one reactant system continues to flow while the other reactant is pulsed, but the substrate is exposed to both reactants during deposition to deposit material during each pulse. For example, the substrate may be exposed to a continuous flow of H _2, the pulse train and providing WF _6, WF ₆ during the pulse and H ₂ react to deposit tungsten.

In contrast, sequential CVD processes perform independent exposure to each reactant such that the reactants do not flow into the chamber simultaneously during deposition. Rather, each reactant flow is introduced sequentially into the chamber in which the substrate is placed with a pulse of transient separation, repeated one or more times in a cyclic manner. Typically, one cycle is the minimum set of operations used to perform a surface deposition reaction. The result of a cycle is the creation of at least a portion of the film layer on the surface of the substrate. The cycle of sequential CVD is further described below.

ALD and nucleation layer deposition also involves exposing the substrate to a transient separation pulse of the two reactants in a cyclic manner. For example, in an ALD cycle, the first reaction is passed to a chamber, the chamber is purged, the second reaction is passed to the chamber, and the chamber is again purged. Typically, such a cycle is repeated to establish a film thickness. In conventional ALD and nucleation layer deposition cycles, the first reactant flow constitutes a first "dose" in the self-limiting reaction. For example, the substrate contains a limited number of active sites, and the first reactant is adsorbed to the substrate. At the active site and saturating the surface, the second reactant reacts with the adsorbent layer to deposit material layer by layer in the cycle.

However, in sequential CVD, the reactants are not necessarily adsorbed on the active sites on the substrate, and in certain embodiments, the reactions may not be self-limiting. For example, reactants used in sequential CVD may have low adsorption rates. Furthermore, when the second reactant is introduced, the reactants on the surface of the substrate may not necessarily react with the second reactant. Rather, in certain embodiments of sequential CVD, certain reactants on the substrate remain unreacted during cycling and are not reacted until later cycles. Certain reactants may not react due to stoichiometric properties, steric hindrance, or other effects.

The methods described herein are carried out on a substrate that may be placed in a chamber. The substrate can be a germanium wafer, such as a 200-mm wafer, a 300-mm wafer, or a 450-mm wafer, including one or more layers of material deposited thereon (eg, a layer of dielectric, conductive, or semi-conductive material) Wafer. The substrate can have features, such as vias or contact openings, which can be characterized by narrow and ∕ or recessed openings, constrictions within the features, and high aspect ratios of one or more. The feature portion may be formed in one or more of the above layers. For example, features can be formed at least partially in the dielectric layer. In certain embodiments, the features 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, or higher. One example of a feature is a hole or via in a layer on a semiconductor substrate or substrate.

1B-1H are schematic illustrations of various structures in which tungsten can be deposited in accordance with the disclosed embodiments. FIG. 1B shows an example of a cross-sectional view of a vertical feature 101 to be filled with tungsten. The feature can include feature holes 105 in the substrate 103. The size of the apertures 105 or other features near the opening (eg, opening diameter or line width) may be between about 10 nm and 500 nm (eg, between about 25 nm and 300 nm). The feature apertures 105 may be referred to as unfilled features or directly referred to as features. A portion of the feature and any features are characterized by a shaft 118 extending through the length of the feature, the vertically oriented feature having a vertical axis and the horizontally oriented feature having a horizontal axis.

In some embodiments, the features are trenches in a 3D NAND structure. For example, the substrate can comprise a word line structure having at least 60 lines, having 18 to 48 layers, and the trenches being at least 200 Å deep. Another example is a trench in a substrate or layer. The feature can have any depth. In various embodiments, the features can have a bottom layer, such as a barrier layer or an adhesive layer. Non-limiting examples of the underlayer include a dielectric layer and a conductive layer such as tantalum oxide, tantalum nitride, tantalum carbide, metal oxide, metal nitride, metal carbide, and metal layers.

FIG. 1C shows an example of a feature 101 having a re-entrant profile. The concave profile is narrowed from the bottom, closed end, or interior of the feature to the contour of the feature opening. According to various embodiments, the profile may be tapered and/or overhanged at the feature opening. Figure 1C shows an example of the latter, with the bottom layer 113 acting as a liner for the sidewall or inner surface of the feature aperture 105. The bottom layer 113 can be, for example, a diffusion barrier layer, an adhesive layer, a nucleation layer, a combination of such layers, or any other suitable material. Non-limiting examples of the bottom layer 113 can include a dielectric layer and a conductive layer such as tantalum oxide, tantalum nitride, tantalum carbide, metal oxide, metal nitride, metal carbide, and metal layers. In a particular embodiment, the bottom layer can be one or more of Ti, TiN, WN, TiAl, and W. The bottom layer 113 forms an overhang 115 such that the thickness of the bottom layer 113 near the opening of the feature portion 101 is thicker than the thickness of the interior of the feature portion 101.

In some embodiments, features having one or more constrictions therein may be filled. Figure 1D shows an example of a view of various fill features with constrictions. Examples of Figures 1D (a), (b), and (c) each of which includes a constriction 109 at an intermediate point within the feature. The constriction 109 can be, for example, a width between about 15 nm and 20 nm. During the deposition of tungsten into the features using conventional techniques, the constrictions may cause pinching, and the deposited tungsten blocks further deposition through the constrictions before the portion of the features is filled, resulting in appearance in the features. Void. Example (b) further includes a cushion ∕ barrier overhang 115 at the feature opening. Such an overhang can also be a potential pinch point. Example (c) includes a constriction 112 that is further from the field than the overhang 115 of the example (b).

Horizontal features, such as horizontal features in a 3-D memory structure, can also be filled. FIG. 1E shows an example of a horizontal feature 150 that includes a constriction 151. For example, horizontal feature 150 can be a word line in a VNAND structure.

In some embodiments, the constrictions may be caused by struts that are present in VNAND or other structures. For example, Figure 1F shows a plan view of a post 125 in a VNAND or Vertical Integrated Memory (VIM) structure 148, while Figure 1G shows a simplified schematic view of a cross-sectional view of the post 125. The arrows in Figure 1F represent the deposited material; as the struts 125 are disposed between the regions 127 and the gas inlet or other deposition source, adjacent struts may create constrictions 151, creating the challenge of void-free filling of the regions 127.

The structure 148 can be formed by, for example, depositing a stack of alternating interlayer dielectric layers 129 and sacrificial layers (not shown) on the substrate 100 and selectively etching the sacrificial layer. The interlayer dielectric layer can be, for example, a tantalum oxide and a tantalum or tantalum nitride layer, and the sacrificial layer is a material that can be selectively etched by an etchant. Etching and deposition processes can then be performed to form pillars 125, which can include channel regions of completed memory components.

The major surface of the substrate 100 may extend in the x and y directions while the pillars 125 are oriented in the z direction. In the example of FIGS. 1F and 1G, the struts 125 are configured in an offset manner such that the struts 125 directly adjacent in the x direction are offset from each other in the y direction, and vice versa. According to various embodiments, the struts (and corresponding constrictions formed by adjacent struts) can be configured in any number of ways. Further, the post 125 can be any shape including a circle, a square, and the like. The post 125 can comprise an annular semiconducting material, or a circular (or square) semiconducting material. A gate dielectric can surround the semiconducting material. The region between each of the interlayer dielectric layers 129 may be filled with tungsten; thus, the structure 148 has a plurality of stacked horizontally oriented features to be filled that extend in the x and ∕ or y directions.

FIG. 1H provides another example of a view of, for example, a VNAND or a horizontal feature that includes other structures of the pillar constrictions 151. The example in Figure 1H is open ended and the material to be deposited can be accessed horizontally by the sides indicated by the arrows. (It should be noted that the example in FIG. 1H can be regarded as a 3D structural feature depicted in 2D, FIG. 1H is a cross-sectional view of the region to be filled, and the pillar constriction shown in the figure represents a flat view rather than a cross-sectional view. The constriction can be seen). In some embodiments, the 3-D structure may be characterized by a region to be filled that extends in two or three dimensions (eg, x and y or x, y, and z directions in the example of FIG. 1G), as compared to Filling holes or trenches that extend along one or two dimensions can create additional challenges. For example, controlling the filling of 3-D structures is very challenging because multiple deposition gases can enter the features from several dimensions.

An example of feature filling for horizontally oriented and vertically oriented features is described below. It should be noted that in most cases, the examples are applicable to both horizontally oriented or vertically oriented features. In addition, it should be noted that in the following description, the term "transverse" can be used to indicate a direction substantially orthogonal to the axis of the feature, and the term "vertical" means a direction substantially along the axis of the feature.

Although the following description focuses on tungsten feature fill, the disclosed aspects can also be practiced to fill features with other materials. For example, feature fills using one or more of the techniques described herein can be used to fill features with other materials, including other tungsten-containing materials (eg, tungsten nitride (WN) and tungsten carbide (WC)), including Titanium materials (for example, titanium (Ti), titanium nitride (TiN), titanium telluride (TiSi), titanium carbide (TiC) and titanium aluminide (TiAl)), germanium-containing materials (for example, tantalum (Ta) and Niobium nitride (TaN), and nickel-containing materials (for example, nickel (Ni) and nickel telluride (NiSi)). Moreover, the methods and apparatus disclosed herein are not limited to feature fills, but can be used to deposit tungsten on any suitable surface, including on a flat surface to form an unpatterned film.

2A provides a process flow diagram of a method implemented in accordance with the disclosed embodiments. Operations 202-210 of Figure 2A are performed to deposit a tungsten nucleation layer by ALD. In various embodiments described herein, the pressure to perform operations 202-210 is lower than operation 280. For example, operations 202-210 can be performed at a low pressure of less than about 10 Torr. In some examples, operations 202-210 are performed at a pressure of about 10 Torr, or a pressure of about 3 Torr. Without being bound by a particular theory, it is believed that the operation of 202-210 at low pressure will result in less fluorine being incorporated into the membrane due to the lower partial pressure of the fluorine-containing precursor in the chamber during film deposition. Reduce the concentration of fluorine in the deposited tungsten film. An example of a process of depositing a tungsten nucleation layer at a low pressure to achieve a low fluorine concentration deposition of tungsten is further described in U.S. Patent Application Serial No. 14/723,275, filed on May 27,.

In operation 202, the substrate is exposed to a tungsten-containing precursor, such as WF _6. For purposes of the description herein, while WF ₆ is used as an example of a tungsten-containing precursor, it should be understood that other tungsten-containing precursors may be suitable for use in practicing the disclosed embodiments. For example, a metal-organic tungsten-containing precursor can be used. Organic-metal precursors and fluorine-free precursors such as MDNOW (methylcyclopentadiene-dicarbonyl nitrosonium-tungsten) and EDNOW (ethylcyclopentadiene-dicarbonyl nitrosonium-tungsten) can also be used. . The tungsten-containing precursor may comprise a combination of these compounds. In certain embodiments, during operation 202, a carrier gas stream may be introduced, such as nitrogen (N ₂ ), argon (Ar), helium (He), or other inert gas.

Operation 202 can be performed for any suitable duration and at any suitable temperature. In some examples, the duration of performing operation 202 can be between about 0.25 seconds and about 30 seconds, about 0.25 seconds and about 5 seconds, or about 0.5 seconds and 3 seconds. In some embodiments, the duration of performing this operation may be sufficient to saturate the active sites on the surface of the substrate.

In operation 204, selectively purge the chamber to remove the excess unadsorbed WF ₆ to the substrate surface. The purge can be performed by flowing the inert gas under a fixed pressure, thereby reducing the pressure of the chamber and maintaining the pressure of the chamber before starting another gas exposure.

In operation 206, the substrate is exposed to a reducing agent to deposit a tungsten nucleation layer. The reducing agent can be borane, decane or decane. Examples of borane include borane (BH ₃ ), diborane (B ₂ H ₆ ), triborane, alkyl borane, amine borane, carborane, and haloborane. Examples of decane include methooxane (SiH ₄ ), dioxane (Si ₂ H ₆ ), trioxane (Si ₃ H ₈ ), alkyl decane, amino decane, carbon decane, and halodecane. The decane includes Ge _n H _n+4 , Ge _n H _n+6 , Ge _n H _{n+8 ,} and Ge _n H _m , where n is an integer from 1 to 10, and n is an integer different from m. Other decanes such as alkyl decane, amino decane, carbon decane, and halodecane may also be used. In general, halodecane may not have significant reducing power, but may have processing conditions and a tungsten-containing precursor suitable for film formation using halodecane.

The implementation of operation 206 can be performed for any suitable duration. In some examples, the exemplary duration is comprised between about 0.25 seconds and about 30 seconds, about 0.25 seconds and about 5 seconds, or between about 0.5 seconds and 3 seconds. In certain embodiments, this operation may be sufficient to react with the WF ₆ adsorption layer on the surface of the substrate. The duration of implementing operation 206 may be outside of these exemplary ranges. In certain embodiments, the carrier gas may be used, e.g., argon (Ar), helium (He) or nitrogen (N _2).

After operation 206, a selective purge step may be performed to purge excess reducing agent that is still in the gas phase and that does not react with WF ₆ on the surface of the feature. The purging can be carried out by flowing the inert gas at a fixed pressure, thereby reducing the pressure of the chamber and maintaining the pressure of the chamber before starting another gas exposure.

In operation 210, it is determined whether the tungsten nucleation layer has been deposited to a suitable thickness. If not, operations 202-208 are repeated until a desired thickness of tungsten nucleation layer is deposited on the surface of the feature. Each iteration of operations 202-208 may be referred to as an ALD "cycle". In some embodiments, the order of operations 202 and 206 may be reversed to cause the reductant to be introduced first.

After the tungsten nucleation layer is deposited to a suitable thickness, in operation 280, bulk tungsten is deposited by sequential CVD. In various embodiments, the pressure to perform operation 280 can be greater than the pressure during operations 202-210. For example, the pressure at which operation 280 is performed can be greater than or equal to about 10 Torr, such as about 10 Torr, or about 40 Torr.

FIG. 2B provides a process flow diagram of operations that may be performed during operation 280. It should be noted that the operation of FIG. 2B can be implemented without implementing the operations of FIG. 2A. FIG. 2C provides a timing sequence diagram to depict an exemplary cycle of sequential CVD in process 200. 3A-3J are schematic diagrams of exemplary mechanisms for sequential CVD cycles.

At operation 282 of FIG. 2B, the exposing the substrate to a reducing agent such as H _2. This operation may be referred to as "pulsing" or "dosing", which may be used interchangeably herein. In an embodiment of the herein, H ₂ as an exemplary system to provide the reducing agent, it should be appreciated that other reducing agents may be used, containing silicon, borane, germane, phosphine, hydrogen-containing gas, and combinations thereof. And various non-sequential CVD, H ₂ pulse train to provide additional reactants without flowing. In some embodiments, a carrier gas can be flowed in. The carrier gas can be any of the carrier gases described with respect to operation 206 in Figure 2A. The implementation of operation 282 can be performed for any suitable duration. In some examples, the exemplary duration is comprised between about 0.25 seconds and about 30 seconds, about 0.25 seconds and about 5 seconds, or between about 0.5 seconds and 3 seconds.

H in FIG. 2C shows deposition cycle 211A in ₂ doses of 220A, which may correspond to operation 282 of FIG. 2B. During the H ₂ dose of 220 A, the carrier gas streamed in, pulverized to provide a reducing agent, and the WF ₆ flow was turned off.

FIG. 3A depicts an exemplary mechanism in which H _{2 is} introduced to a substrate 300 on which a tungsten nucleation layer 301 is deposited. Gaseous hydrogens (311a and 311b) are introduced, and some of the H ₂ (313a and 313b) are on the surface of the tungsten nucleation layer 301, but may not necessarily adsorb to the surface. For example, H ₂ may not be necessarily chemically adsorbed on the nucleation layer 301, in some embodiments, may be physically adsorbed to the upper surface 301 of the nucleation layer.

Returning to Figure 2B, in operation 284, the chamber is purged. This purge operation removes excess H _{2 which} is still in the gas phase. The purging can be carried out by flowing the inert gas at a fixed pressure, thereby reducing the pressure of the chamber and maintaining the pressure of the chamber before starting another gas exposure. The purge of the chamber can be carried out for any suitable duration, for example, for a duration of between about 0.1 seconds and about 3 seconds. Operation 284 of Figure 2B may correspond to the purge phase 240A of Figure 2C. As shown in Fig. 2C, during the purge phase 240A, the carrier gas is caused to flow but the H ₂ flow and the WF ₆ flow are closed. 3B shows an exemplary diagram in which previously hydrogen in the gaseous state (311a and 311b in FIG. 3A) is blown out of the chamber while the hydrogen (313a and 313b) previously on the surface is maintained in the tungsten nucleation layer 301. On the surface.

Returning to Figure 2B, in operation 286, the substrate is exposed to a tungsten-containing precursor (e.g., WF _6), to form a sub-monolayer film on the substrate. In various embodiments, during this operation, WF ₆ flows to the chamber for a duration of between about 0.1 seconds and about 3 seconds, or for about 0.5 seconds. In certain embodiments, WF ₆ can be diverted to fill gas lines and pipeline changes prior to dosing. In certain embodiments, WF ₆ flows to the chamber but does not fully react with all of the H ₂ molecules on the surface of the substrate. Operation 286 may correspond to WF ₆ dose 260A in Figure 2C. As shown in Figure 2C, during the WF ₆ dose of 260 A, the carrier gas was flowed, the H ₂ flow was turned off, and the WF ₆ flow was turned on.

FIG. 3C shows an exemplary overview of operation 286 of FIG. 2B. In Figure 3C, the substrate is exposed to WF _6, WF ₆ gaseous number (331 a and 331b), and some WF ₆ at or near the surface of the substrate (323a and 323b).

During operation 286 of FIG. 2B, a number of WF ₆ may be retained from a previous dose and H ₂ on the surface of the reaction. As shown in FIG. 3D, WF ₆ may be reacted with H ₂ to temporarily form intermediate product 343b, whereby in FIG. 3E, intermediate product 343b is completely reacted to leave nucleation layer 301 of tungsten 390 on the surface of substrate 300. Above, and HF is in a gaseous state (351a and 351b, for example).

During operation 286 of FIG. 2B, a number of WF ₆ may not be retained from previous dose and H ₂ on the surface of the complete reaction. As shown in FIG. 3D, WF ₆ may react with the H ₂ moiety to form an intermediate product 343a, whereby in FIG. 3E, the intermediate product 343a remains partially reacted on the nucleation layer 301 on the surface of the substrate 300. For the deposition of tungsten nucleation layer, the reaction mechanism involving WF ₆ and H ₂ may be slower than the reaction between borane or decane or decane and WF ₆ due to activation energy barrier and steric effect. For example, without limitation to a particular theory, the stoichiometry of WF ₆ can use at least three H ₂ molecules to react with one WF ₆ molecule. It is possible that WF ₆ reacts partially with the H ₂ molecule instead of forming tungsten to form an intermediate product. For example, this may occur when there is not enough H ₂ in its vicinity to react with WF ₆ according to stoichiometric principles (eg, three H ₂ molecules are used to react with one WF ₆ molecule), thus leaving intermediate product 343a On the surface of the substrate.

During operation 286 of FIG. 2B, a number of WF ₆ may not completely react with H _2, but may not physically adsorbed on the substrate surface H ₂ of physically adsorbed or retained. In certain embodiments, WF ₆ may remain on the surface of the substrate, but may not physically adsorb or chemisorb to the surface.

Thus, in many embodiments, operation 286 of FIG. 2B may form a sub-monolayer of tungsten. For example, after performing operations 282-286, it is possible to deposit a single layer having a thickness of about 0.3 Å.

At operation 288 of FIG. 2B, the purge chamber to remove unreacted WF byproducts from the chamber ₆ and the gas. In certain embodiments, the non-sequential CVD reaction characteristics may increase during the too short purge duration in operation 288, and thus a higher stress film will be deposited. In certain embodiments, the purge duration is between about 0.1 seconds and about 2 seconds, and it is possible to prevent removal of all WF ₆ from the substrate surface due to the low adsorption rate of WF ₆ to the tungsten surface. In certain embodiments, the purge duration is between about 0.1 seconds and about 15 seconds, such as about 7 seconds. For example, for the fabrication of a 3D NAND structure, during operation 288, the chamber can be blown off for about 7 seconds. The duration of blowing is dependent on the substrate and stress.

Operation 288 of Figure 2B may correspond to the purge phase 270A of Figure 2C. As shown in FIG. 2C, the purge phase 270A ends the deposition cycle 211A. Figure 3F provides an exemplary schematic view of the substrate as the chamber is purged. It should be noted that compound 343c may be an intermediate product that has formed but is not fully reacted, while some tungsten 390 may be formed on the substrate. Each cycle thereby forms a single layer of tungsten on the substrate.

In some embodiments, operations 286 and 282 may be reversed such that 286 is performed prior to operation 282. In some embodiments, 282 can be implemented prior to operation 286.

In operation 290 of FIG. 2B, it is determined whether the bulk tungsten has been deposited to a suitable thickness. If not, then operations 282-288 are repeated until deposition to the desired thickness. In some embodiments, operations 282-288 are repeated until the features are filled. In FIG. 2C, it is determined yet bulk tungsten deposited to a suitable thickness, the operation is repeated in FIG. 2B deposition cycle of 282-288 211B, and thus H ₂ doses embodiment 220B, followed by blowing stage 240B. A WF ₆ dose 260B is implemented, followed by another purge phase 270B.

As an example, FIG. 3G show the operation of the repetitive cycle 282, whereby gaseous H ₂ 311c is introduced to the substrate 390 and the tungsten intermediate portion of the reaction product 343d deposited on the substrate. It should be noted that the introduced H ₂ may now completely react with the intermediate product 343d on the substrate, leaving the reacted compound 343d leaving the deposited tungsten 390b and 390c and forming gaseous by-products HF 351c and 351d, as shown in Figure 3H. Show. Some H ₂ 311c may remain in a gaseous state, while some H ₂ 313c may remain on the tungsten layer 390a. In FIG. 3I, the purge chamber (thereby corresponds to operation 284 of FIG. 2B, 2C, or the operation of FIG. 240B), leaving the deposited tungsten 390a, 390b, 390c, and some of the H ₂ 313c. In FIG. 3J, again introducing WF ₆ to enabling 331c and 323c may then molecule and / or with H ₂ and the substrate adsorption. FIG. 3J may correspond to operation 286 of FIG. 2B or 260B of FIG. 2C. After the WF ₆ dose, the chamber can be purged again and the cycle can be repeated again until deposition to the desired thickness of tungsten.

The tungsten film deposited using the disclosed embodiments has a low fluorine concentration, for example, about two orders of magnitude lower than the fluorine concentration of tungsten deposited by non-sequential CVD. Deposition conditions such as temperature, pulse time, and other parameters can be varied depending on hardware or process modifications. The total tensile stress of the film can be less than about 1 GPa.

3K provides a process flow diagram of a method implemented in accordance with the disclosed embodiments. In operation 280, bulk tungsten is deposited by sequential CVD. The processing conditions and chemicals can be as described above with respect to Figures 2B and 3A-3J. In operation 299, bulk tungsten is deposited by non-sequential CVD. During non-sequential CVD, the substrate is simultaneously exposed to a tungsten-containing precursor and a reducing agent to deposit bulk tungsten. Exemplary tungsten-containing precursors include a fluorine-containing precursor (eg, WF ₆ ), a chlorine-containing precursor (eg, WCl _x ), and tungsten hexacarbonyl (W(CO) ₆ ). An exemplary reducing agent comprises hydrogen. In some embodiments, the deposition of non-sequential CVD is performed by exposing the substrate to WF ₆ and H ₂ . Operations 280 and 299 may be performed sequentially, or any operation 280 may be performed one or more times before or after operation 299 is performed. In some embodiments, operations 280 and 299 can be performed in a pulsed manner such that operation 299 is performed for each implementation operation 280 two or more cycles. Thus, bulk tungsten can be deposited using a combination of sequential CVD and non-sequential CVD.

The disclosed embodiments can have a variety of applications in tungsten deposition processes. For example, in some embodiments, the filling of the features can be performed by alternately a reducing agent (eg, borane, decane, or decane) and a pulsed ALD cycle of WF ₆ to deposit a tungsten nucleation layer, followed by The CVD is performed in the order of FIG. 2B to deposit bulk tungsten.

In another example, in certain embodiments, the tungsten nucleation layer can be deposited using a reducing agent and an ALD cycle of WF ₆ followed by a reducing agent and a fluorine-free tungsten-containing precursor (eg, a metal-organo-tungsten precursor) The fluorine-free tungsten CVD of the material) and the combination of the sequential CVD of FIG. 2B as described above are used to deposit the bulk tungsten. The fluorine-free tungsten precursor may also contain a tungsten carbonyl compound (W(CO) ₆ ) and a tungsten chloride (WCl _x ) such as tungsten pentachloride (WCl ₅ ) and tungsten hexachloride (WCl ₆ ).

In another example, a tungsten nucleation layer can be deposited on the features by alternate aging cycles of a reducing agent and a pulse of WF ₆ and can be performed by sequential CVD and non-sequential CVD as described above with respect to FIG. 2B. The body tungsten is deposited alternately. For example, bulk tungsten can be deposited using several sequential CVD cycles between predetermined durations of non-sequential CVD. In a particular example, bulk tungsten deposition can be performed using about 5 sequential CVD cycles followed by 5 seconds of non-sequential CVD followed by 5 sequential CVD cycles and another 5 seconds of non-sequential CVD.

In another example, the filling of the features can be performed by first depositing a tungsten nucleation layer by alternating aging cycles of a reducing agent and WF ₆ pulses, then partially filling the features using sequential CVD, and by non-sequential CVD. Fill in the rest of the features.

In another example, the filling of the features can be performed by depositing a tungsten nucleation layer by alternating aging cycles of a reducing agent and a pulse of WF ₆ , followed by partial deposition of bulk tungsten by sequential CVD, and CVD by fluorine-free tungsten. The body fill is completed (for example, using a metal-organic tungsten precursor). For example, it may be implemented in a number of sequential cycles CVD tungsten and partially filled with a body feature, then exposed to the same time by using MDNOW H CVD ₂ and to fill the remaining portion of the feature. It should be noted that in some embodiments, the filling of features may not deposit a nucleation layer, but the nucleation layer may assist in reducing the growth retardation of bulk tungsten.

It will be appreciated that various combinations of the applications described herein can be used to deposit tungsten, and the methods are not limited to the examples presented herein. For example, a tungsten-containing tungsten precursor (WCl _x ) (eg, tungsten pentachloride (WCl ₅ ) and tungsten hexachloride (WCl ₆ ) may be used instead of using WF ₆ or in the examples described herein) WF ₆ is used together.

In various embodiments, a soak or surface treatment operation can be performed prior to depositing the nucleation layer. An exemplary immersion or surface treatment comprises exposing the substrate to formane (SiH ₄ ), dioxane (Si ₂ H ₆ ), trioxane (Si ₃ H ₈ ), decane (GeH ₄ ), argon (Ar), six Tungsten fluoride (WF ₆ ), diborane (B ₂ H ₆ ), hydrogen (H ₂ ), nitrogen (N ₂ ) gas, or a combination thereof. In certain embodiments, one or more gases may be used to soak the substrate. For example, in certain embodiments, the substrate can be exposed to decane for a first duration and then exposed to diborane for a second duration. Such an operation can also repeat a complex cycle. In another example, the substrate can be exposed to diborane for a first duration and then exposed to decane for a second duration. In another example, the substrate can be exposed to diborane during a first duration and then exposed to hydrogen during a second duration. In another example, the substrate can be exposed to decane during a first duration and then exposed to hydrogen during a second continuation. In certain embodiments, the substrate can be exposed to nitrogen and combined with any of the soaking treatments described above. In any of the disclosed embodiments, the chamber in which the substrate is placed may be purged between one or more soaking operations. Purging can be carried out by flowing an inert gas such as argon into the chamber. For example, in one example, the substrate can be exposed to diborane for a first duration, then the chamber can be purged, and then the substrate can be exposed to the decane for a second duration.

By alternating between the tungsten-containing precursor and the reducing agent, a nucleation layer can be deposited according to certain disclosed embodiments prior to deposition of the bulk tungsten layer, such as for example, methane (SiH ₄ ), dioxane (Si) ₂ H ₆ ), trioxane (Si ₃ H ₈ ), decane (GeH ₄ ), or diborane (B ₂ H ₆ ). In some embodiments, the nucleation layer can be deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and decane. In some embodiments, the nucleation layer can be deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane. In some embodiments, the nucleation layer can be deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and decane, followed by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane. In some embodiments, the nucleation layer can be deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane, followed by exposing the substrate to alternating pulses of tungsten-containing precursor and decane. In some embodiments, the substrate can be exposed to a tungsten-containing precursor by exposing the substrate to alternating pulses of tungsten-containing precursor and decane, followed by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane. And alternating pulses of decane, thus depositing a nucleation layer. In some embodiments, the substrate can be exposed to a tungsten-containing precursor by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane, followed by exposing the substrate to alternating pulses of tungsten-containing precursor and decane. And alternating pulses of diborane, thus depositing a nucleation layer. In any of the disclosed embodiments, the chamber in which the substrate is placed may be purged between one or more dose operations for depositing the nucleation layer. Purging can be carried out by flowing an inert gas such as argon into the chamber. Any suitable inert gas can be used for purging. For example, in some embodiments, the substrate can be exposed to a pulse containing a tungsten precursor, and then the chamber can be purged, then the substrate can be exposed to a pulse of decane, and the chamber can be purged again, which can be repeated in a cyclic manner. Operation.

The nucleation layer deposition that can be used in any of the above embodiments can be included throughout the nucleation deposition process, or during the decane dose, or during the diborane dose, or at the tungsten-containing precursor dose (eg, WF). Any of hydrogen (H ₂ ), argon (Ar), nitrogen (N ₂ ), or a combination thereof, during a ₆ dose period, or at any purge time. In certain embodiments, the substrate is formed by exposing the substrate to a combination of methotane, dioxane, trioxane, decane, diborane, hydrogen, tungsten hexafluoride, nitrogen, argon, and combinations thereof A surface treatment operation may be performed during or after nuclear growth. For example, during nucleation layer deposition, the substrate can be exposed to alternate pulses of Silane WF ₆ and then, and then exposing the substrate to the silane-soaking, then re-expose the substrate to the _silane-6 and WF of alternating pulses. Such an operation can be performed in a cyclic manner. For example, in certain embodiments, the following cycle may be repeated to deposit a nucleation layer: SiH ₄ and WF ₆ of the alternating pulses, and exposed to the surface treatment.

In some embodiments, the nucleation layer can be deposited by exposing the substrate to any one or more of any one or more of the tungsten-containing precursor and the following gases in any order, in one or more cycles: diboron Alkanes, formane, dioxane, trioxane, hydrogen, nitrogen, and decane (GeH ₄ ). For example, in some embodiments, deposition of the nucleation layer can be performed by exposing the substrate to diborane, exposing the substrate to tungsten hexafluoride, exposing the substrate to formoxane, and exposing the substrate to hydrogen. This can be repeated in one or more cycles. In another example, in some embodiments, the deposition of the nucleation layer can be performed by exposing the substrate to diborane, exposing the substrate to hydrogen, and exposing the substrate to tungsten hexafluoride. This can be repeated in one or more cycles. In another example, in some embodiments, the deposition of the nucleation layer can be performed by exposing the substrate to nitrogen, exposing the substrate to diborane, and exposing the substrate to tungsten hexafluoride. This can be repeated in one or more cycles. In another example, in some embodiments, the deposition of the nucleation layer can be performed by exposing the substrate to decane, exposing the substrate to nitrogen, and exposing the substrate to tungsten hexafluoride. This can be repeated in one or more cycles. In any of the embodiments, the substrate can be exposed to a surface treatment and/or a immersion operation before, during, or after deposition using any nucleation cycle of available gas. In certain embodiments, additional gas may be co-flowing with any of the gases described above during exposure to one or more nucleation deposition processes. In any of the disclosed embodiments, the chamber in which the substrate is placed may be purged between one or more dose operations for depositing the nucleation layer. Purging can be carried out by flowing an inert gas such as argon into the chamber. Any suitable inert gas can be used for purging.

The deposition of the bulk tungsten can be carried out using the embodiments disclosed herein and the application of the US Patent Application No. 14/723,275, filed on May 27, 2015. For reference. In any of the above embodiments, the bulk tungsten may also be periodically deposited, and re-nucleation and/or immersion and/or surface treatment and/or conventional CVD deposition operations may be performed between the deposition of the body. For example, in some embodiments, the embodiment disclosed above with respect to FIG. 2B can be used to deposit bulk tungsten, followed by suspension of bulk tungsten deposition, followed by exposure of the substrate to formane and WF ₆ or diborane and WF ₆ The alternating pulses are used to re-nucleate the surface of the substrate, and then the bulk tungsten deposition can be restarted using the embodiment disclosed above with respect to Figure 2B. This can be repeated in any number of cycles. In another example, in some embodiments, the embodiment disclosed above with respect to FIG. 2B can be used to deposit bulk tungsten, followed by suspending bulk tungsten deposition, followed by methane, dioxane, trioxane, The substrate is exposed to a soak or surface treatment to treat the surface of the substrate by flowing any of decane, diborane, hydrogen, tungsten hexafluoride, nitrogen, argon, and combinations thereof, and then using the above-described disclosure with respect to Figure 2B The embodiment re-starts bulk tungsten deposition. The bulk tungsten deposition can be performed by exposing the substrate to a tungsten-containing precursor (eg, WF ₆ ) and any one or more of the following gases: hydrogen, formane, dioxane, trioxane, diborane, nitrogen, argon. And decane. The bulk tungsten may also be deposited using a combination of the sequential CVD described above with respect to Figure 3K and conventional CVD. Conventional CVD can be performed before or during the use of sequential CVD to deposit bulk tungsten, such as during cycling between sequential and conventional CVD.

In some embodiments, the substrate can be annealed at any suitable temperature prior to depositing the bulk tungsten and after depositing the nucleation layer. In some embodiments, the substrate can be annealed at any suitable temperature after deposition of the bulk tungsten layer. In some embodiments, the substrate can be annealed at any suitable temperature during the intermediate period of deposition of the bulk tungsten. It may be annealed at any suitable gas atmosphere, for example comprising the gaseous environment in which one or more of the: tungsten-containing gas (e.g. WF _6), hydrogen, methyl Silane, two Silane, tris Silane, diborane, nitrogen , argon, and decane.

In various embodiments, the chamber in which the substrate is placed may be evacuated or before or after the dose of the tungsten-containing precursor and reducing agent used to deposit the bulk tungsten according to the embodiment disclosed above with respect to FIG. 2B. Blowing off. In certain embodiments, the delay time can be incorporated into the sequential CVD deposition dose or purge step described herein. In certain embodiments, one or more gases may be co-flowed during a dose or purge operation using either one or more of the following gases: WF ₆ , hydrogen, formane, dioxane, trioxane, Diborane, nitrogen, argon, and decane.

The substrate temperature during nucleation deposition may differ from the substrate temperature during the sequential CVD described above with respect to Figure 2B. It should be understood that the substrate temperature represents the temperature set by the susceptor supporting the substrate. The disclosed embodiments can be practiced at any suitable pressure, such as a pressure greater than about 10 Torr, or a pressure less than about 10 Torr. For a multi-station chamber, each pedestal can be set to a different temperature. In some embodiments, each pedestal can be set to the same temperature. During any or all of the above operations in accordance with the disclosed embodiments, the substrate may be rotated between stations. The chamber pressure can also be adjusted in one or more of the disclosed embodiments. In certain embodiments, the chamber pressure during nucleation deposition is different than the chamber pressure during bulk deposition. In certain embodiments, the chamber pressure during nucleation deposition is the same as the chamber pressure during bulk deposition.

During either of the above exposures, the gas may be pulsed or continuously flowing. For example, in certain embodiments, the dosage of WF ₆ during the sequential CVD operations, may provide a WF ₆ or more times during dose in a single pulse. Likewise, in certain embodiments, the inert gas may be pulsed one or more times during a single purge operation during purge. Such pulsed operation can be performed during any operation of any operation or bulk deposition of nucleation deposition, or any combination thereof. In some embodiments, one or more changes to one or more parameters (eg, pressure, flow rate, and temperature) can be used. In some embodiments, during any operation of nucleation deposition or bulk deposition or both, the movable susceptor can adjust the gap between the substrate and the showerhead on the susceptor. Movement of the pedestal can incorporate changes in one or more parameters (eg, pressure, temperature, or flow rate). Adjusting the gap between the substrate and the showerhead may affect the pressure, temperature, or flow rate that may be used in accordance with certain disclosed embodiments. It should be understood that any of the processes described herein may be applied to techniques related to ALD. device

Any suitable chamber can be used to implement the disclosed embodiments. Exemplary deposition equipment includes various systems, such as ALTUS ^® and ALTUS ^® Max from Lam Research Corp. of Fremont, California, or any of a variety of other commercially available processing systems. In some embodiments, sequential chemical vapor deposition (CVD) can be performed at a first station, the first station being one of two, five, or even more deposition stations disposed in a single deposition chamber. Thus, for example, at the first station, hydrogen (H ₂ ) and tungsten hexafluoride (WF ₆ ) can be alternately introduced to the surface of the semiconductor substrate using a separate gas supply system that creates a local balloon on the surface of the substrate. Another station can be used for fluorine-free tungsten deposition, or non-sequential CVD. Another station can be used to deposit a tungsten nucleation layer at low pressure. Two or more stations can be used to deposit tungsten in a parallel process. Alternatively, the wafer can be indexed to have sequential CVD operations performed sequentially at two or more stations.

4 is a block diagram of a processing system suitable for performing a tungsten thin film deposition process according to an embodiment. System 400 includes a transfer module 403. The transfer module 403 provides a clean pressurized environment to minimize the risk of contamination of the substrate being processed as the substrate being processed moves between different reactor modules. Multi-station reactor 409 is mounted on transfer module 403, which can perform atomic layer deposition (ALD) and sequential CVD according to an embodiment. In some embodiments, multi-station reactor 409 can also be used to perform fluorine-free tungsten deposition and or non-sequential CVD. Reactor 409 can include a plurality of stations 411, 413, 415, and 417 that can be sequentially operated in accordance with the disclosed embodiments. For example, reactor 409 can be configured such that station 411 performs nucleation layer deposition by ALD, station 413 performs sequential CVD, station 415 performs fluorine-free tungsten deposition, and station 417 performs non-sequential CVD. The station may include a heated susceptor or substrate support, one or more gas inlets or a showerhead or dispersion plate. An example of a deposition station 500 is depicted in FIG. 5 and includes a substrate support 502 and a showerhead 503. A heater may be disposed in the base portion 501.

One or more single or multi-station modules 407 may also be mounted on the transfer module 403, which may perform plasma or chemical (non-plasma) pre-cleaning. The module can also be used in a variety of processes to, for example, prepare a substrate for deposition processing. System 400 also includes one or more wafer source modules 401 that store wafers before and after processing. An atmospheric pressure robot arm (not shown) in the atmospheric pressure transfer chamber 419 first moves the wafer from the source module 401 to a load lock 421. The wafer transfer device (typically a robot arm unit) in the transfer module 403 moves the wafer from the load lock chamber 421 to a plurality of modules mounted on the transfer module 403 and between the plurality of modules.

In various embodiments, system controller 429 is used to control processing conditions during deposition. Controller 429 typically includes one or more memory devices and one or more processors. The processor can include a CPU or computer, an analog and/or digital input/output connection, a stepper motor controller board, and the like.

Controller 429 can control all activities of the deposition device. System controller 429 executes system control software including timing for controlling specific processing, gas mixing, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power level, wafer chuck or pedestal position, And the instruction set of other parameters. In some embodiments, other computer software stored in a memory device associated with the controller can be used.

Typically, there is a user interface associated with controller 429. The user interface can include a graphical software display that displays screens, devices and/or processing conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, and the like.

System control logic can be configured in any suitable manner. In general, the logic can be designed or configured in hardware and/or software. The instructions used to control the drive circuitry can be hard coded or provided as software. Instructions may be provided by "programming." It should be understood that such programming encompasses any form of logic, including in digital signal processors, special application integrated circuits, and other devices having a particular algorithm implemented as hardware. Encoding logic. It should also be understood that the programming includes software or firmware instructions that can be executed on a general purpose processor. The system control software can be encoded in any suitable computer readable programming language.

Computer code for controlling helium-containing reductant pulses, hydrogen flow, and tungsten-containing precursor pulses, and other processing in the processing sequence can be written in any conventional computer readable programming language: for example, a combination language, C , C++, Pascal, Fortran, or others. The compiled object code or script is executed by the processor to perform the tasks specified in the program. As also mentioned, the code can be hard coded.

The controller parameters are related to processing conditions such as process gas composition and flow rate, 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 can be entered using the user interface.

Signals for monitoring processing may be provided by analogy and/or digital input connections of system controller 429. The signal output for control processing is on the analog and digital output connections of the deposition apparatus 400.

System software can be designed or configured in many different ways. For example, various chamber component sub-brouts or control articles can be written to control the operation of the chamber components required to perform the deposition process in accordance with the disclosed embodiments. Examples of programs or program segments for this purpose include a substrate location code, a process gas control code, a pressure control code, and a heater control code.

In some embodiments, controller 429 is part of the system and may be part of the above examples. Such a system may comprise a semiconductor processing apparatus comprising a processing tool or a plurality of processing tools, a chamber or a plurality of chambers, for processing one or more platforms, and/or a specific processing element (wafer base, gas flow) System, etc.). These systems can be integrated with electronic components that are used to control the operation of these systems before, during, and after processing semiconductor wafers or substrates. Electronic components may be referred to as "controllers" that control the various components or sub-portions of the system or systems. Depending on the processing requirements and/or type of system, controller 429 may be programmed to control the disclosure herein. Any processing, including: processing gas delivery, temperature setting (eg, heating and/or cooling), pressure setting, vacuum setting, power setting, radio frequency (RF) generator settings in some systems, RF matching circuit settings , frequency setting, flow rate setting, fluid transport settings, position and operational settings, access to a tool and other transfer tools and/or wafer transfer to a lock chamber that is connected or bonded to a particular system.

Broadly speaking, a controller can be defined as having various integrated circuits, logic, memory, and ports for receiving commands, issuing commands, controlling operations, enabling cleaning operations, enabling end point measurements, and achieving similar functions. Or software electronic components. The integrated circuit may include a firmware in the form of a firmware for storing program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and/or one or more microprocessors, or an execution program. A microcontroller for instructions (eg, software). Program instructions may be instructions that are passed to the controller in various separate settings (or program files) that define operational parameters for performing particular processing on or on the semiconductor wafer. In some embodiments, the operational parameters may be defined by the process engineer to be in one or more layers of the wafer, material, metal, oxide, germanium, germanium dioxide, surface, circuitry, and germanium or die. Part of a recipe that completes one or more processing steps during the manufacturing period.

In some embodiments, controller 429 can be part of a computer or coupled to a computer, integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller 429 can be in the "cloud" or in all or a portion of the factory host computer system that is remotely controlled to allow wafer processing. The computer can enable remote control of the system to monitor the current manufacturing operation. Process, verify historical records of past manufacturing operations, verify trends or performance measures for complex manufacturing operations, change current processing parameters, set processing steps after current processing, or start new processing. In some examples, remote A computer (such as a server) can provide processing recipes to the system via the network, and the network can include a local area network or an Internet. The remote computer can include a user interface, and the user interface allows input of parameters and/or settings. Or stylized, the parameters and/or settings are then passed from the remote computer to the system. In some examples, the controller receives instructions in the form of data that are to be executed during one or more operations Each of the processing steps specifies a parameter. It should be understood that the parameters can be selected for the type of processing to be performed and the controller Or the type of tool that controls it. Thus, as noted above, the controllers may be decentralized, such as by including network connections and working toward a common target, such as the processing and control described herein. One or more independent controllers. An example of a decentralized controller for such a target would be one or more integrated circuits in the chamber, the one or more integrated circuits being located at the far end (eg Combined with one or more integrated circuit communications at the platform level or as part of a remote computer to control processing in the chamber.

By way of non-limiting example, an exemplary system can include a plasma etch chamber or module, a deposition chamber or module, a rotary cleaning chamber or module, a metal plating chamber or module, a cleaning chamber or module, and a tilt Edge etching chamber or module, physical vapor deposition (PVD) chamber or module, CVD chamber or module, ALD chamber or module, atomic layer etching (ALE) chamber or module, ion implantation A chamber or module, a track chamber or module, and any other semiconductor processing system relating to or used in the processing and fabrication or fabrication of semiconductor wafers.

As noted above, depending on the processing steps to be performed by the tool, the controller can communicate with one or more of the following: other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, proximity Tools, tools located throughout the plant, host computer, another controller, or material transfer tool that moves wafer containers into and out of the tool location and/or load in a semiconductor manufacturing facility.

Controller 429 can include a variety of programs. The substrate positioning program can include code for controlling the chamber components for loading the substrate onto the base or chuck and controlling the distance between the substrate and other portions of the chamber, such as gas inlets and ports or objects. The process gas control program can include code for controlling gas composition, flow rate, pulse time, and optionally for flowing gas into the chamber prior to deposition to stabilize the pressure in the chamber. The pressure control program can include code for controlling the pressure in the chamber by adjusting, for example, a throttle valve in the exhaust system of the chamber. The heater control program can include code to control the current supplied to the heating unit used to heat the substrate. Alternatively, the heater control program can control the delivery of heat transfer gases (eg, helium) to the wafer chuck.

Examples of chamber sensors that can be monitored during deposition include mass flow controllers, pressure sensors (such as pressure gauges), and thermocouples located on the base or chuck. Properly programmed feedback and control algorithms can be used with data from these sensors to maintain desired process conditions.

The foregoing describes the implementation of the disclosed embodiments in a single or multi-chamber semiconductor processing tool. The device processing described herein can be used in conjunction with a lithographic patterning tool or process, for example, for the fabrication or production of semiconductor components, displays, LEDs, solar photovoltaic panels, and the like. Typically, although not necessarily, such tooling processes will be used together or in a common manufacturing facility. The lithographic patterning of the film typically involves some or all of the following steps, each step being provided by several possible tools: (1) coating of the photoresist on the workpiece (ie, the substrate), using a rotary or spray tool (2) curing of the photoresist, using a heating plate or a heating furnace or a UV curing tool; (3) exposing the photoresist to visible light or UV light or x-ray light with a tool (such as a wafer stepper); (4) The photoresist is developed to selectively remove and thereby pattern the photoresist using a tool (eg, a wet cleaning station); (5) transfer the photoresist pattern to the underlying film or work by using a dry or plasma assisted etching tool And (6) using a tool (such as RF or microwave plasma photoresist stripper) to remove the photoresist. Experiment experiment 1

The experiment was carried out with respect to four treatments for depositing bulk tungsten at 395 ° C and 40 Torr. In each treatment, the bulk tungsten is deposited on the tungsten nucleation layer, and the tungsten nucleation layer is atomic layer deposition (ALD) using alternating diborane (B ₂ H ₆ ) and tungsten hexafluoride (WF ₆ ) cycles. And deposition. Figure 6 provides an exemplary pulse scheme for each of these four processes. In Process 1, H ₂ and WF ₆ flow simultaneously and continuously into the chamber as during conventional chemical vapor deposition (CVD). In Process 2, the H ₂ system is continuously flowing, while the WF ₆ is pulsed (for example, pulsed CVD). In Process 3, the WF ₆ system is continuously flowing, while the H ₂ system is pulsed (for example, pulsed CVD). In Process 4, H ₂ and WF ₆ are alternately pulsed as described above with respect to the method of Figure 2B (e.g., sequential CVD). The thickness of the tungsten nucleation layer, and the stress, non-uniformity, and resistivity of the film deposited using each of the four treatments were measured and consolidated in Table 1 below. Table 1, resistivity and stress

As shown in Table 1, both the stress and resistivity of the tungsten film deposited using Process 4 were significantly lower than those deposited using either of Processes 1-3. Experiment 2

The experiment is performed on a process for depositing bulk tungsten on two substrates, both of which comprise a titanium nitride (TiN) barrier layer and a tungsten nucleation layer, and the tungsten nucleation layer is alternated by B ₂ H ₆ and WF. ₆ cycles of ALD deposition. A substrate involves bulk tungsten deposition using non-sequential CVD involving simultaneous exposure of the substrate to WF ₆ and H ₂ at 300 °C. Another substrate involves bulk tungsten deposition using sequential CVD as described above with respect to Figure 2B, involving alternating pulses of WF ₆ and H ₂ at a chamber pressure of 10 Torr. The fluorine concentration was measured for both substrates. The conditions of this experiment are shown in Table 2. The results are plotted in Figure 7. Table 2, conditions of experiment 2

Line 700 shows the fluorine concentration of a substrate having tungsten deposited by non-sequential CVD. Line 701 shows the fluorine concentration of the substrate having tungsten deposited by sequential CVD. The W/TiN interface line at about 350 Å represents the interface between the tungsten nucleation layer and the TiN barrier layer. The TiN/oxide interface dotted line at about 475 Å represents the interface between the TiN barrier layer and the oxide. It should be noted that the fluorine concentration on the y-axis of the graph is on the order of magnitude, and the sequential CVD fluorine concentration 701 is substantially lower than the non-sequential CVD fluorine concentration 700, and at some substrate depths, the fluorine concentration is lower to two orders of magnitude. Experiment 3

The experiment was carried out with respect to the treatment of depositing bulk tungsten on a substrate under different pressures. Each of the three substrates includes a TiN barrier layer. The deposition of a tungsten nucleation layer of a substrate is alternately cycled by ALD of B ₂ H ₆ and WF ₆ at 10 Torr, followed by exposure of the substrate to the bulk tungsten of WF ₆ and H ₂ at 300 ° C. CVD. The deposition of the tungsten nucleation layer of the other substrate is alternately cycled by ALD of B ₂ H ₆ and WF ₆ at 10 Torr, followed by alternating tungsten of WF ₆ and H ₂ at 10 Torr. Sequential CVD. The ALD deposition of the tungsten nucleation layer of the third substrate is performed by alternating cycles of B ₂ H ₆ and WF ₆ at 3 Torr, followed by the use of alternating tungsten of WF ₆ and H ₂ at 10 Torr. Sequential CVD. The fluorine concentration was measured for the substrate. The conditions of this experiment are shown in Table 3. The results are plotted in Figure 8. Table 3, conditions of experiment 3

Line 800 represents the fluorine concentration of the first substrate in which the bulk tungsten is deposited by non-sequential CVD. A broken line 801 indicates the fluorine concentration of the second substrate in which a nucleation layer is deposited at 10 Torr, followed by sequential CVD to deposit bulk tungsten. Dotted line 803 represents the fluorine concentration of the third substrate in which a nucleation layer is deposited at 3 Torr, followed by sequential CVD to deposit bulk tungsten. The results show that the low pressure nucleation layer followed by sequential CVD (803) has a lower fluorine concentration than the second substrate (801), even at the W/TiN interface and even in the TiN layer (between 350 Å and 475 Å). This suggests that by reducing the amount of fluorine in the tungsten film, it is possible to reduce the diffusion of fluorine into the TiN layer and oxide. Experiment 4

The experiment was performed with respect to the treatment of depositing bulk tungsten on the substrate using different combinations of tungsten deposition. Compare the three substrates. A substrate comprising 1 kÅ of thermal oxide, 30 Å TiN, 18 Å tungsten nucleation layer deposited using ALD alternating pulses of WF ₆ and B ₂ H ₆ at 3 Torr, and WF ₆ and H ₂ at 10 Torr The bulk tungsten deposited by sequential CVD pulses. The fluorine concentration of this substrate is depicted by the dashed line 912 in FIG. The other substrate comprises a 1 kÅ thermal oxide, 30 Å TiN, 10 Å fluorine-free tungsten, a 12 Å tungsten nucleation layer deposited using ALD alternating pulses of WF ₆ and B ₂ H ₆ at 3 Torr, and by 10 The bulk tungsten deposited by sequential CVD using WF ₆ and H ₂ pulses under Torr. The fluorine concentration of this second substrate is depicted by line 911 in FIG. The third substrate comprises a 5 kÅ TEOS-deposited oxide, 30 Å of fluorine-free tungsten, a 12 Å tungsten nucleation layer deposited using ALD alternating pulses of WF ₆ and B ₂ H ₆ at 3 Torr, and by 10 Torr The bulk tungsten deposited by sequential CVD using WF ₆ and H ₂ is used. The fluorine concentration of this substrate is depicted by the dotted line 913 in FIG. The layers deposited on each of the substrates of this experiment are organized in Table 4. Table 4, conditions of experiment 4

As shown in Figure 9, the fluorine concentration of the film deposited using a combination of fluorine-free tungsten, low-pressure nucleation layer, and sequential CVD has less fluorine diffusion (see line 911 and line 913, beyond the W/TiN interface, depth). More than 425 Å). For a film with more fluorine-free tungsten deposited on the substrate, the fluorine concentration near the nucleation layer is the lowest between 300 Å and 425 Å, and is deposited without a fluorine-free tungsten layer, using sequential CVD and low-pressure nucleation. The bulk tungsten has a lower fluorine concentration between about 50 Å and 300 Å (see line 912). These results suggest that the combination of sequential CVD deposition of fluorine-free tungsten and tungsten may cause the tungsten film to reach a relatively low fluorine concentration and reduce fluorine diffusion. Experiment 5

The experiment was carried out with respect to the treatment of a film deposited by sequential CVD and a combination of low pressure and high pressure nucleation layer deposition. A substrate comprises a tungsten nucleation layer deposited using an ALD alternating cycle of WF ₆ and B ₂ H ₆ at 10 Torr, and the bulk tungsten deposition is performed by using WF ₆ and H ₂ at 10 Torr according to Figure 2B above. The sequential CVD of alternating pulses. The stress and resistivity of the film were measured at various thicknesses and shown in line 1001 "low pressure nucleation" in Figures 10A and 10B. The other substrate contained an ALD alternating cycle using WF ₆ and B ₂ H ₆ at 40 Torr. Depositing a tungsten nucleation layer, and the bulk tungsten deposition is performed by sequential CVD using alternating pulses of WF ₆ and H ₂ at 10 Torr according to Figure 2B above. The stress and resistivity of the film are measured at various thicknesses, and Line 1002 "high pressure nucleation" shown in Figures 10A and 10B. The conditions for nucleation and bulk layer deposition are shown in Table 5. Table 5, conditions of experiment 5

As shown in the results, the stress of the substrate having the nucleation layer deposited at a low pressure is substantially lower than that of the substrate having the nucleation layer deposited under high pressure, and the resistivity remains substantially the same. Experiment 6

The experiment was carried out with respect to the treatment of a film deposited by sequential CVD and a combination of low temperature and high temperature nucleation layer deposition. A substrate comprises a tungsten nucleation layer deposited using ALD alternating cycles of WF ₆ and B ₂ H ₆ at 10 Torr and 250 ° C, and the bulk tungsten deposition is performed by using WF at 10 Torr according to Figure 2B above. Sequential CVD of alternating pulses of ₆ and H ₂ . The stress and resistivity of the film were measured at various thicknesses and shown in line 1102 of Figure 11A and 11B "low temperature nucleation. Another substrate comprised WF ₆ and B ₂ H ₆ at 10 Torr and 300 °C. The ALD alternately circulates the deposited tungsten nucleation layer, and the bulk tungsten deposition is performed by sequential CVD using alternating pulses of WF ₆ and H ₂ at 10 Torr according to Figure 2B above. The film stress is measured at various thicknesses. The resistivity, and is shown in line 1104 in Figures 11A and 11B, "High Temperature Nucleation". The conditions for nucleation and bulk layer deposition are shown in Table 5. Table 6, conditions of experiment 6

As shown in the results, the stress of the substrate having the nucleation layer deposited at a low temperature is substantially lower than that of the substrate having the nucleation layer deposited at a high temperature, and the resistivity of the film deposited at a higher temperature is slightly lower. It is lower than the resistivity of the film deposited at a lower temperature. These results suggest that the combination of lower temperature deposition of the nucleation layer and sequential CVD host deposition can significantly reduce the stress of the film. in conclusion

Although the above-described embodiments have been described in detail for the purpose of clarity, it is apparent that certain modifications and changes may be made in the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and devices of the present embodiments. Therefore, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments of the present invention should not be limited to the details set forth herein.

100‧‧‧Substrate
101‧‧‧Vertical features
103‧‧‧Substrate
105‧‧‧Characteristic holes
109‧‧‧Contraction
112‧‧‧Contraction
113‧‧‧ bottom layer
115‧‧‧Overhanging
118‧‧‧Axis
125‧‧‧ pillar
127‧‧‧Area
129‧‧‧Interlayer dielectric
148‧‧‧structure
150‧‧‧Horizontal Features
151‧‧‧Contraction
190‧‧‧Substrate
192‧‧‧矽
194‧‧‧Oxide layer
196‧‧‧ barrier layer
198‧‧‧Tungsten nucleation layer
199‧‧‧Main body tungsten layer
200‧‧‧Process
202,204,206,208,210,280‧‧‧ operations
211A, 211B‧‧‧Sedimentation cycle
220A, 220B H ₂ ‧‧‧ dose
240A, 240B‧‧‧ blowing phase
260A, 260B WF ₆ ‧‧‧ dose
270A, 270B‧‧ ‧ blowing phase
280,282,284,286,288,290,299‧‧‧ operations
300‧‧‧Substrate
301‧‧‧Tungsten nucleation layer
311a, 311b, 311c, 313a, 313b, 313c H ₂ 331a, 331b, 331c, 323a, 323b, 323c WF ₆ 343a, 343b, 343d‧‧‧ intermediate
343c‧‧‧ compound
351a, 351b, 351c, 351d HF 390, 390a, 390b, 390c‧‧ ‧ tungsten
400‧‧‧ system
401‧‧‧ Wafer source module
403‧‧‧Transmission module
407‧‧‧Module
409‧‧‧Multi-site reactor
411,413,415,417‧‧
419‧‧‧Normal pressure transfer chamber
421‧‧‧Load lock room
429‧‧‧System Controller
500‧‧‧deposition station
501‧‧‧Base section
502‧‧‧Substrate support
503‧‧‧Sprinkler
700‧‧‧ line
701‧‧‧ line
800‧‧‧ line
801‧‧‧ dotted line
803‧‧‧ dotted line
Line 911‧‧
912‧‧‧ dotted line
913‧‧‧ dotted line
Line 1001‧‧
Line 1002‧‧
Line 1102‧‧
Line 1104‧‧

FIG. 1A is a schematic view of an exemplary film on a substrate.

1B-1H are schematic illustrations of various structures in which tungsten can be deposited in accordance with the disclosed embodiments.

2A and 2B are process flow diagrams illustrating the operation of the method in accordance with the disclosed embodiments.

2C is a timing sequence diagram showing an exemplary loop in a method in accordance with the disclosed embodiments.

3A-3J are schematic diagrams illustrating examples of film deposition mechanisms in accordance with the disclosed embodiments.

3K is a process flow diagram illustrating the operation of the method in accordance with the disclosed embodiments.

4 is a schematic diagram illustrating an exemplary processing tool for performing the disclosed embodiments.

Figure 5 is a schematic diagram illustrating an exemplary processing station for performing the disclosed embodiments.

Figure 6 illustrates various timing sequence diagrams.

Figure 7-11B is a graph of experimental results.

700‧‧‧ line

701‧‧‧ line

Claims (22)

A method of filling a feature, comprising: (a) exposing a substrate to an alternating pulse of a reducing agent and a first tungsten-containing precursor in a chamber to deposit a tungsten nucleation layer on the substrate; (b) exposing the substrate to alternating pulses of hydrogen and a second tungsten-containing precursor to deposit a bulk tungsten layer on the tungsten nucleation layer, wherein the chamber pressure during step (a) is no greater than 10 Torr . The method of filling the features of claim 1, further comprising: (c) simultaneously exposing the substrate to a reducing agent and a third tungsten-containing precursor to deposit a second bulk tungsten layer. The method of filling the feature part of claim 2, further comprising: (d) performing step (c) every two or more cycles of step (b), wherein one of the steps (b) comprises hydrogen Pulses and pulses of the second tungsten-containing precursor. The method of filling a feature according to any one of claims 1-3, wherein the step (b) is carried out in a plurality of cycles comprising a pulse of hydrogen and a pulse of the tungsten-containing precursor, each cycle forming a thickness of at least A single layer of about 0.3 Å. A method of filling a feature according to any one of claims 1-3, wherein the first tungsten-containing precursor is different from the second tungsten-containing precursor. A method of filling a feature of claim 5, wherein the first tungsten-containing precursor is fluorine-free. A method of filling a feature according to any one of claims 1-3, wherein the deposited tungsten nucleation layer and the deposited bulk tungsten layer have a tensile stress of less than about 1 GPa per 500 Å of deposition. A method of depositing tungsten on a substrate, the method comprising: (a) depositing a tungsten layer on the substrate by (i) exposing the substrate to a reducing agent; and (ii) exposing the substrate to a first fluorine-free tungsten-containing precursor; and (b) depositing a bulk tungsten layer in a plurality of cycles, the cycles comprising: (i) exposing the substrate to hydrogen (H ₂ ); (ii) exposing the substrate Up to a second tungsten-containing precursor; and (iii) repeating steps (i) through (ii) one or more cycles to deposit the bulk tungsten layer. A method of depositing tungsten on a substrate according to claim 8 wherein the first fluorine-free tungsten-containing precursor is selected from the group consisting of a metal-organic tungsten-containing precursor and tungsten hexacarbonyl. A method of depositing tungsten on a substrate as in claim 8 or 9, wherein the tungsten layer in step (a) is deposited to a thickness of between about 2 Å and about 100 Å. A method of depositing tungsten on a substrate as in claim 8 or 9, wherein each cycle in step (b) forms a single layer having a thickness of at least about 0.3 Å. A method of filling a feature, comprising: (a) exposing a substrate to alternating pulses of hydrogen and a first tungsten-containing precursor to deposit a bulk tungsten layer on the substrate; and (b) simultaneously exposing the substrate And a second tungsten-containing precursor and a reducing agent to deposit a second bulk tungsten layer on the substrate. A method of filling a feature according to claim 12, wherein steps (a) and (b) are sequentially repeated. The method of claim 12, wherein the tungsten-containing precursor in step (b) is a fluorine-free tungsten-containing precursor, and the fluorine-free tungsten-containing precursor is selected from the group consisting of metal-organic A group consisting of a tungsten-containing precursor, a tungsten chloride, and a tungsten hexacarbonyl. The method of filling a feature according to any one of claims 12-14, wherein the first tungsten-containing precursor is different from the second tungsten-containing precursor. An apparatus for processing a substrate, the apparatus comprising: (a) at least one processing chamber including a base for supporting a substrate; (b) at least one exhaust port for coupling to a vacuum; One or more process gas inlets coupled to one or more process gas sources; and (d) a controller for controlling the plurality of operations in the apparatus, comprising a plurality of machine readable instructions for: i) introducing a reducing agent and a first tungsten-containing precursor to the processing chamber in an alternating pulse; and (ii) introducing hydrogen and a second tungsten-containing precursor to the processing chamber in an alternating pulse manner, Wherein the chamber pressure during step (i) is no more than 10 Torr. The apparatus for processing a substrate according to claim 16, wherein the controller further comprises a plurality of mechanically readable instructions for: (iii) simultaneously introducing a reducing agent and a third tungsten-containing precursor to the processing chamber a chamber to deposit a second bulk tungsten layer. An apparatus for processing a substrate according to claim 16, wherein the controller further comprises a plurality of mechanically readable instructions for: (iv) performing two or more cycles per step (ii), implementing step (iii) And wherein one of the steps (ii) comprises a pulse of hydrogen and a pulse of the second tungsten-containing precursor. An apparatus for processing a substrate according to any one of claims 16 to 18, wherein the first tungsten-containing precursor is different from the second tungsten-containing precursor. An apparatus for processing a substrate according to any one of claims 16 to 18, wherein the first tungsten-containing precursor is fluorine-free. An apparatus for processing a substrate, the apparatus comprising: (e) at least one processing chamber including a base for supporting a substrate; (f) at least one exhaust port for coupling to a vacuum; One or more process gas inlets coupled to one or more process gas sources; and (h) a controller for controlling the plurality of operations in the apparatus, comprising a plurality of machine readable instructions for: i) introducing hydrogen and a first tungsten-containing precursor to the processing chamber in an alternating pulse to deposit a bulk tungsten layer; and (ii) simultaneously introducing a second tungsten-containing precursor and a reducing agent to the processing chamber a chamber to deposit a second bulk tungsten layer. An apparatus for processing a substrate according to claim 21, wherein the controller further comprises a plurality of mechanically readable instructions for: sequentially repeating steps (i) and (ii).