JP2017008412A - Low fluorine tungsten deposition by subsequent cvd process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a low stress tungsten film having a low fluorine content.SOLUTION: The tungsten film forming method includes: (a) a tungsten core forming layer deposition step by exposing alternate pulses of a reductant and a first tungsten-containing precursor on a substrate repeatedly in two cycles or more under a chamber pressure of 10 Torr or less; (b) a bulk tungsten deposition step by exposing alternate pulses of hydrogen and a second tungsten-containing precursor on the tungsten core forming layer to the substrate so as to deposit bulk tungsten, after the step (a); and (c) a second bulk tungsten deposition step by exposing the substrate on the reductant and a third tungsten-containing precursor so as to deposit second bulk tungsten. The step (c) is performed for each of two cycles or more of (b), and a hydrogen pulse and a second tungsten-containing precursor pulse are included in one cycle of the step (b), in the method. The first tungsten-containing precursor is fluorine free, in the method.SELECTED DRAWING: Figure 7

Description

  The deposition of tungsten-containing materials is an integral part of many semiconductor manufacturing processes. Such materials may be used for horizontal wiring, vias between adjacent metal layers, contacts between metal layers on the silicon substrate and the device, 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 to deposit a very thin portion of a tungsten film that functions as a seed layer or nucleation layer. The remaining portion of the tungsten film (bulk layer) is then deposited on the nucleation layer by exposing the substrate to two reactants simultaneously. In general, the bulk layer is deposited at a higher rate than the nucleation layer. However, as the device shrinks and more complex patterning schemes are used in the industry, the deposition of tungsten thin films becomes a challenge.

  Provided herein are methods and apparatus for depositing tungsten. One aspect relates to a method for filling a feature, the method comprising: (a) exposing a substrate to alternating pulses of a reducing agent and a tungsten-containing precursor in a chamber to deposit a tungsten nucleation layer on the substrate. And (b) exposing the substrate to alternating pulses of hydrogen and a tungsten-containing precursor to deposit a bulk tungsten layer over the tungsten nucleation layer, wherein the chamber pressure in (a) is 10 Torr or less.

  The method may further include (c) exposing the substrate to the reducing agent and the tungsten-containing precursor simultaneously to deposit a second bulk tungsten layer. The method may further comprise performing (c) as (d) every two or more cycles of (b), wherein one cycle of (b) includes a pulse of hydrogen and a tungsten-containing precursor. Includes body pulses.

  In various embodiments, (b) is performed in a cycle comprising a pulse of hydrogen and a pulse of a tungsten-containing precursor, with each cycle forming a subatomic layer having a thickness of at least about 0.3 mm.

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

  The deposited tungsten can have a tensile stress of less than about 1 GPa per 500 liters of deposition.

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

  In some embodiments, the fluorine-free tungsten-containing precursor is selected from the group consisting of organometallic tungsten-containing precursors, tungsten chloride, and hexacarbonyltungsten.

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

  In (a), the tungsten layer may be deposited to a thickness between about 2 and about 100 inches. Each cycle in (b) may form a subatomic layer having a thickness of at least about 0.3 mm.

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

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

  The tungsten-containing precursor in (b) may be a fluorine-free tungsten-containing precursor selected from the group consisting of organometallic tungsten-containing precursors, tungsten chloride, and hexacarbonyl tungsten.

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

  Another aspect relates to an apparatus for processing a substrate, the apparatus comprising: (a) at least one processing chamber having a pedestal configured to hold the substrate; and (b) in a vacuum. At least one outlet for connection; (c) one or more process gas inlets connected to one or more process gas sources; and (d) a controller for controlling operation in the apparatus. A controller for (i) introducing a reducing agent and a tungsten-containing precursor into the processing chamber in alternating pulses; and (ii) introducing hydrogen and a tungsten-containing precursor into the processing chamber in alternating pulses. The machine pressure in (i) is less than 10 Torr, including machine readable instructions.

  Another aspect relates to an apparatus for processing a substrate, the apparatus comprising: (a) at least one processing chamber having a platform configured to hold a substrate; and (b) at least for connecting to a vacuum. An outlet; (c) one or more process gas inlets connected to one or more process gas sources; and (d) a controller for controlling operation in the apparatus, the controller comprising: (I) to deposit a bulk tungsten layer, to introduce hydrogen and a tungsten-containing precursor into the processing chamber in alternating pulses, and (ii) to deposit a second bulk tungsten layer. And machine readable instructions for simultaneously introducing the reducing agent into the processing chamber. The controller may further include machine readable instructions for sequentially repeating (i) and (ii).

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

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

FIG. 1B is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1C is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1D is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1E is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1F is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1G is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments. FIG. 1H is a schematic example of various structures on which tungsten can be deposited according to the disclosed embodiments.

FIG. 2A is a process flow diagram illustrating the operation of the method according to the disclosed embodiments. FIG. 2B is a process flow diagram illustrating the operation of the method according to the disclosed embodiments.

FIG. 2C is a timing sequence diagram illustrating an exemplary cycle of a method according to disclosed embodiments.

FIG. 3A is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3B is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3C is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3D is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3E is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3F is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3G is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3H is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3I is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments. FIG. 3J is a schematic diagram of an example mechanism for depositing a film in accordance with the disclosed embodiments.

FIG. 3K is a process flow diagram illustrating the operation of the method according to the disclosed embodiments.

FIG. 4 is a schematic diagram of an exemplary process tool for implementing the disclosed embodiments.

FIG. 5 is a schematic diagram of an exemplary station for implementing the disclosed embodiments.

FIG. 6 shows various timing sequence diagrams.

FIG. 7 is a plot of experimental results. FIG. 8 is a plot of experimental results. FIG. 9 is a plot of experimental results. FIG. 10A is a plot of experimental results. FIG. 10B is a plot of experimental results. FIG. 11A is a plot of experimental results. FIG. 11B is a plot of the experimental results.

  In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments presented. 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 in order not to unnecessarily obscure the disclosed embodiments. Although the disclosed embodiments are described in connection with specific embodiments, it will be understood that they are not intended to limit the disclosed embodiments.

  Feature filling with tungsten (W) is often used to make electrical contacts in the manufacture of semiconductor devices. As the device scales to finer technology nodes and more complex patterning structures are used, various challenges arise in tungsten filling. One challenge is to reduce the fluorine concentration or content in the tungsten film after deposition. Compared to larger features, smaller features have a greater impact on device performance if they have the same fluorine concentration in the tungsten film as the larger features. For example, the smaller the feature, the thinner the film is deposited. As a result, the fluorine in the deposited tungsten film is more likely to diffuse through the thinner film, which can cause device failure.

  One way to prevent fluorine diffusion is to deposit one or more barrier layers to prevent fluorine from diffusing from tungsten to other layers of the substrate, such as an oxide layer, before depositing tungsten. Can be mentioned. For example, FIG. 1A shows an exemplary stack of layers deposited on a substrate. The substrate 190 includes a silicon layer 192, an oxide layer 194 (eg, titanium oxide (TiOx), tetraethylorthosilicate (TEOS) oxide, etc.), a barrier layer 196 (eg, titanium nitride (TiN)), and a tungsten nucleus. A formation layer 198 and a bulk tungsten layer 199 are included. Barrier layer 196 is deposited to prevent diffusion of fluorine from bulk tungsten layer 199 and tungsten nucleation layer 198 into the oxide layer. However, as the device shrinks, the barrier layer becomes thinner and fluorine may still diffuse from the deposited tungsten layer. Performing bulk tungsten chemical vapor deposition at higher temperatures results in reduced fluorine content, but such films have poor step coverage.

  Another challenge is to reduce the resistance of the tungsten film after deposition. Thinner films tend to have higher resistance compared to thicker films. As features get smaller, the contact or line resistance of tungsten increases due to scattering effects in thinner tungsten films. The low resistivity tungsten film minimizes power loss and overheating in integrated circuit designs. The tungsten nucleation layer generally has a higher electrical resistivity than the bulk layer above it. Barrier layers deposited on contacts, vias, and other features can also have high resistivity. In addition, thin barriers and tungsten nucleation films occupy a larger percentage for smaller features, increasing the overall resistance in the features. The resistivity of the tungsten film depends on the thickness of the deposited film, and as the thickness decreases, the resistivity increases due to boundary effects.

  Another challenge is to reduce the stress in the film after deposition. Thinner tungsten films tend to have greater tensile stress. Conventional techniques for depositing bulk tungsten films by chemical vapor deposition have a tensile stress in excess of 2.5 GPa for a 200 膜 film. The high thermal tensile stress causes the substrate to curl, which makes subsequent processing difficult. For example, subsequent processes may include chemical mechanical planarization, material deposition, and / or clamping the substrate to a substrate holder to perform the process in a chamber. However, these processes often rely on the substrate being flat, with a curled substrate resulting in non-uniform processing or being unable to process the substrate. Become. Although there are existing methods to reduce stress in films of other materials, such as annealing, tungsten has a surface mobility that allows the movement or change of particles after deposition because of its high melting point. Not done.

  In this specification, a method for depositing a tungsten film having a low fluorine concentration using a sequential CVD process is provided. The deposited film can further have low stress. These methods involve introducing hydrogen and a tungsten-containing precursor such as tungsten hexafluoride in cycles. The disclosed embodiments may be integrated with other tungsten deposition processes to deposit low stress tungsten films that have significantly lower fluorine content than conventional CVD deposited films. For example, the sequential CVD process may be integrated with a low pressure nucleation layer deposition, a fluorine free tungsten layer deposition, and / or a non-sequential CVD process. The disclosed embodiments have a wide range of applications. The methods may be used to deposit tungsten in features with high step coverage, and further used to deposit tungsten in 3D NAND structures and vertical NAND structures, including those with deep trenches. Also good.

Sequential CVD processes are distinguished from non-sequential CVD, pulsed CVD, atomic layer deposition (ALD), and nucleation layer deposition. A non-sequential CVD process involves simultaneous exposure to two reactants, thus causing both reactants to flow simultaneously during deposition. For example, bulk tungsten can be deposited by simultaneously exposing the substrate to hydrogen (H ₂ ) and tungsten hexafluoride (WF ₆ ) for a duration sufficient to fill the feature. During exposure, hydrogen and WF ₆ react to deposit tungsten in the feature. In a pulsed CVD process, one reactant is continuously flowed in while the other reactant is pulsed, but during deposition, the substrate is exposed to both reactants so that the material is transferred during each pulse. Deposit. For example, the substrate may be exposed to a continuous flow of H ₂ while WF ₆ is pulsed, and tungsten is deposited by the reaction of WF ₆ and H ₂ during the pulse.

  In contrast, in a sequential CVD process, each reactant is exposed separately, so that during deposition, the reactants do not flow into the chamber at the same time. Rather, each reactant stream is introduced into the chamber containing the substrate sequentially in time-separated pulses and repeated one or more times in a cycle. In general, one cycle is the minimum set of steps used to perform a surface deposition reaction once. The result of one cycle is the creation of at least a partial film layer on the substrate surface. The sequential CVD cycle will be described later in more detail.

  ALD and nucleation layer deposition also involve exposing the substrate to two reactants in temporally separated pulses and in cycles. For example, in an ALD cycle, a first reactant is flowed into the chamber, the chamber is purged, a second reactant is flowed into the chamber, and the chamber is purged again. Such a cycle is generally repeated to form a film thickness. In conventional ALD and nucleation layer deposition cycles, the first reactant stream represents the first “dose” in the self-regulating reaction. For example, the substrate has a limited number of active sites so that the first reactant is adsorbed on the active sites on the substrate to saturate its surface and the second reactant is adsorbed on the adsorption layer The material is deposited one layer at a time by reacting with.

  On the other hand, in sequential CVD, reactants do not necessarily adsorb to active sites on the substrate, and in some embodiments, the reaction may not be self-limiting. For example, the reactant used in sequential CVD may have a low adsorption rate. Further, the reactant on the substrate surface may not necessarily react with the second reactant when the second reactant is introduced. Rather, in some embodiments of sequential CVD, some reactants on the substrate remain unreacted during the cycle and do not react until the next cycle. Some reactants may not react due to stoichiometric properties, steric hindrance, or other effects.

  The methods described herein are performed on a substrate that can be housed in a chamber. The substrate can be, for example, a silicon wafer that is a 200 mm wafer, a 300 mm wafer, or a 450 mm wafer, and a wafer having one or more material layers, such as a dielectric material, a conductive material, or a semiconductor material deposited thereon. included. The substrate may have features such as vias or contact holes, which feature one or more of narrow and / or reentrant openings, constrictions in the features, high aspect ratios. It can be. Features may be formed in one or more of the above layers. For example, the features can be at least partially formed in the dielectric layer. In some embodiments, the features can 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 even higher. An example of a feature is a hole or via in a semiconductor substrate or a layer on the substrate.

  1B-1H are schematic examples of various structures on which tungsten may be deposited according to the disclosed embodiments. FIG. 1B shows an example of a cross-sectional view of a vertical feature 101 filled with tungsten. The features may include feature holes 105 in the substrate 103. The hole 105 or other feature may have, for example, an opening diameter or line width, as a dimension near the opening, between about 10 nm and 500 nm, such as between about 25 nm and about 300 nm. Feature hole 105 may be referred to as an unfilled feature or simply a feature. Such a feature 101, and any feature, may be partially characterized by an axis 118 that extends over the length of the feature, with vertically oriented features having a vertical axis and horizontally oriented features having a horizontal axis. Have.

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

  FIG. 1C shows an example of a feature 101 having a reentrant profile. A reentrant profile is a profile that squeezes from the closed bottom or interior of the feature toward the feature opening. According to some implementations, the profile may gradually narrow and / or include an overhang in the feature opening. FIG. 1C shows an example of the latter, in which the sidewall or inner surface of the feature hole 105 is lined by the lower layer 113. The lower layer 113 can be, for example, a diffusion barrier layer, an adhesion layer, a nucleation layer, a combination thereof, or any other compatible material. Non-limiting examples of lower layers can include dielectric layers and conductive layers, such as silicon oxide, silicon nitride, silicon carbide, metal oxide, metal nitride, metal carbide, and metal layers Can be included. In a specific implementation, the lower layer can be one or more of Ti, TiN, WN, TiAl, W. The lower layer 113 forms an overhang 115, so that the lower layer 113 is thicker than the inside of the feature 101 in the vicinity of the opening of the feature 101.

  In some implementations, features that have one or more constrictions within the feature may be filled. FIG. 1D shows an example of a diagram filled with various features having constrictions. Each of the examples (a), (b), and (c) of FIG. 1D includes a constriction 109 at an intermediate point in the feature. The constriction 109 can be, for example, between about 15 nm and 20 nm wide. During tungsten deposition in a feature using conventional techniques, the deposited tungsten hinders the previous deposition beyond the constriction before the portion of the feature is filled, so that the constriction is It can cause pinch-off, resulting in voids in the feature. Example (b) further includes a liner / barrier overhang 115 in the feature opening. Such an overhang can still be a pinch-off point. Example (c) includes a constriction 112 at a further distance from the field region than the overhang 115 in Example (b).

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

  In some implementations, the constriction may be due to the presence of pillars in the VNAND or other structure. FIG. 1F shows a plan view of the pillar 125 in, for example, a VNAND or vertical integrated memory (VIM) structure 148, and FIG. 1G shows a schematic cross-sectional view of the pillar 125. The arrow in FIG. 1F represents the deposition material, and the pillar 125 is located between the region 127 and the gas inlet or other deposition source, so that adjacent pillars result in voids in the region 127. It can become the constriction part 151 which presents the subject in free filling.

  The structure 148 can be formed, for example, by depositing a stack of alternating interlevel dielectric layers 154 and sacrificial layers (not shown) on the substrate 100 and selectively etching the sacrificial layers. it can. The interlayer dielectric layer may be, for example, a silicon oxide and / or silicon nitride layer, and the sacrificial layer may be of a material that can be selectively etched by an etchant. This may be followed by an etch and deposition process to form pillars 125, which may include the channel region of the completed memory device.

  The main surface of the substrate 100 can extend in the x direction and the y direction, while the pillar 125 faces the z direction. In the example of FIGS. 1F and 1G, the pillars 125 are arranged in an offset manner, so that the pillars 125 that are directly adjacent in the x direction are offset from each other in the y direction, and vice versa. Depending on the various implementations, pillars (as well as constrictions formed correspondingly by adjacent pillars) can be arranged in many ways. Further, the pillar 125 may have an arbitrary shape including a circular shape, a square shape, and the like. The pillar 125 may include an annular semiconductor material or a circular (or square) semiconductor material. The semiconductor material can be surrounded by a gate dielectric. The region between each of the interlevel dielectric layers 129 can be filled with tungsten, and thus the structure 148 extends in the x and / or y direction and is stacked to be filled. With horizontally oriented features.

  FIG. 1H presents another example of a horizontal feature diagram of, for example, a VNAND or other structure that includes a pillar constriction 151. The example of FIG. 1H is open-ended and allows the material to be deposited to flow horizontally from both sides as indicated by the arrows (note that the example of FIG. 1H can be viewed as a 2D rendering of the 3D feature, and FIG. 1H is a cross-sectional view of the filled region, where the pillar constriction shown in the figure is a constriction that would be seen in a plan view rather than a cross-sectional view That is). In some implementations, the 3D structure can be characterized by a filling region extending along two or three dimensions (eg, the x, y direction, or the x, y, z direction in the example of FIG. 1G), The filling may present more challenges than filling holes or trenches that extend along one or two dimensions. For example, controlling the filling of a 3D structure can be difficult because deposition gases can flow into the feature from multiple dimensions.

  Examples of feature filling for horizontal and vertical features are described below. It should be noted that these examples are often applicable to either horizontally or vertically oriented features. Further, in the following description, the term “lateral direction” is used to refer to a direction substantially perpendicular to the feature axis, and the term “vertical direction” may be used to refer to a direction substantially along the feature axis. It should also be noted.

  Although the following description focuses on feature filling with tungsten, aspects of the present disclosure may be implemented in feature filling with other materials. For example, feature filling using one or more of the techniques described herein can be performed using other tungsten-containing materials (eg, tungsten nitride (WN), tungsten carbide (WC)), titanium-containing materials (eg, titanium (Ti ), Titanium nitride (TiN), titanium silicide (TiSi), titanium carbide (TiC), titanium aluminide (TiAl)), tantalum-containing materials (eg, tantalum (Ta), tantalum nitride (TaN)), nickel-containing materials (eg, , Nickel (Ni), nickel silicide (NiSi)), etc., may be used to fill the feature. Further, the methods and apparatus disclosed herein can be used to deposit tungsten on any suitable surface, such as to form a blanket film on a flat surface, without being limited to feature filling. it can.

  FIG. 2A presents a process flow diagram for a method performed in accordance with the disclosed embodiments. Operations 202-210 of FIG. 2A are performed to deposit a tungsten nucleation layer by ALD. In various embodiments described herein, operations 202-210 are performed at a lower pressure than operation 280. For example, operations 202-210 may be performed at a low pressure less than about 10 Torr. In some examples, operations 202-210 are performed at a pressure of about 10 Torr, or about 3 Torr. Without being bound by a particular theory, performing operations 202-210 at a low pressure allows more fluorine to be incorporated into the film by lowering the partial pressure of the fluorine-containing precursor in the chamber when depositing the film. It is considered that the fluorine concentration in the tungsten film after deposition is reduced because it is small. An example of a process for depositing a tungsten nucleation layer at low pressure to achieve a low fluorine concentration in tungsten after deposition is described in US patent application Ser. No. 14 / 723,275 filed May 27, 2015. (Agency reference number LAMRP 183 / 3623-1 US).

In operation 202, exposing the substrate to a tungsten-containing precursor such as WF _6. For purposes of illustration herein, WF ₆ is used as an example of a tungsten-containing precursor, but it is understood that other tungsten-containing precursors may be suitable for practicing the disclosed embodiments. Should. For example, an organometallic tungsten-containing precursor may be used. Alternatively, organometallic precursors and fluorine-free precursors such as MDNOW (methylcyclopentadienyl-dicarbonylnitrosyl-tungsten) and EDNOW (ethylcyclopentadienyl-dicarbonylnitrosyl-tungsten) may be used. The tungsten-containing precursor may include a combination of these compounds. In some embodiments, in operation 202, a carrier gas such as nitrogen (N ₂ ), argon (Ar), helium (He), or other inert gas may be flowed.

  Operation 202 may be performed at any suitable temperature for any suitable duration. In some examples, operation 202 may be between about 0.25 seconds and about 30 seconds, between about 0.25 seconds and about 5 seconds, or between about 0.5 seconds and about 3 seconds. It can be carried out over a duration. This operation may be performed for a duration sufficient to saturate active sites on the substrate surface in some embodiments.

In operation 204, optionally, the chamber is purged to remove excess WF ₆ that has not adsorbed to the substrate surface. Purging can be performed by reducing the chamber pressure by flowing an inert gas at a constant pressure and repressurizing the chamber before initiating exposure to another gas.

In operation 206, the substrate is exposed to a reducing agent to deposit a tungsten nucleation layer. The reducing agent may be borane, silane, or germane. Examples of borane include borane (BH ₃ ), diborane (B ₂ H ₆ ), triborane, alkylborane, aminoborane, carborane, and haloborane. Examples of silanes include silane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), alkyl silane, amino silane, carbosilane, and halosilane. Germanium 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 m is an integer different from n It is. Other germane may be used, for example, alkyl germane, aminogermane, carbogermane, and halogermane. In general, halogermanes may not have as much reduction potential, but there may be process conditions and tungsten-containing precursors suitable for film formation using halogermanes.

Operation 206 may be performed for any suitable duration. In some examples, examples of duration include between about 0.25 seconds and about 30 seconds, between about 0.25 seconds and about 5 seconds, or between about 0.5 seconds and about 3 seconds. The duration is included. In some embodiments, this operation may be sufficient to react with the WF ₆ adsorption layer on the substrate surface. Operation 206 may be performed for a duration outside the scope of these examples. In some embodiments, a carrier gas such as, for example, argon (Ar), helium (He), or nitrogen (N ₂ ) may be used.

After operation 208, an optional purge step may be provided to purge excess reducing agent that remains in the gas phase that has not reacted with WF ₆ on the feature surface. Purging can be performed by reducing the chamber pressure by flowing an inert gas at a constant pressure and repressurizing the chamber before initiating exposure to another gas.

  In operation 210, it is determined whether the tungsten nucleation layer has been deposited to a sufficient thickness. If not, operations 202-208 are repeated until a desired thickness of the tungsten nucleation layer is deposited on the feature surface. 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 so that the reducing agent is introduced first.

  After the tungsten nucleation layer is deposited to an appropriate thickness, bulk tungsten is deposited by sequential CVD at operation 280. In various embodiments, operation 280 may be performed at a higher pressure than the pressure in operations 202-210. For example, operation 280 may be performed at a pressure of about 10 Torr or greater, for example, about 10 Torr, or about 40 Torr.

  FIG. 2B presents a process flow diagram for operations that may be performed at operation 280. It should be noted that the operation of FIG. 2B may be performed without performing the operation of FIG. 2A. FIG. 2C presents a timing sequence diagram illustrating an exemplary cycle of sequential CVD in process 200. 3A-3J are schematic diagrams of exemplary mechanisms for sequential CVD cycles.

In Figure 2B, in operation 282, exposing the substrate to a reducing agent such as H _2. This operation is sometimes referred to as “pulse” or “dose”, which can be used interchangeably herein. In the embodiments described herein, H ₂ is presented as an example of a reducing agent, but other reducing agents such as silane, borane, germane, phosphine, hydrogen-containing gas, and combinations thereof may be used. It will be appreciated. Unlike non-sequential CVD, H ₂ is pulsed without the flow of other reactants. In some embodiments, a carrier gas may be flowed. The carrier gas can be any of those described above with respect to operation 204 of FIG. 2A. Operation 282 may be performed for any suitable duration. In some examples, examples of duration include between about 0.25 seconds and about 30 seconds, between about 0.25 seconds and about 5 seconds, or between about 0.5 seconds and about 3 seconds. The duration is included.

In FIG. 2C, deposition cycle 211A shows H ₂ dose 220A, which may correspond to operation 282 in FIG. 2B. During H ₂ dose 220A, the carrier gas is flowed in, the reducing agent is pulsed, and the WF ₆ flow is turned off.

FIG. 3A shows an exemplary mechanism for incorporating H ₂ into the substrate 300 on which the tungsten nucleation layer 301 has been deposited. Hydrogen is introduced in the gas phase (311a and 311b) and some H ₂ (313a and 313b) is on the surface of the tungsten nucleation layer 301 but may not necessarily adsorb to the surface. For example, H ₂ may not necessarily be chemically adsorbed on the nucleation layer 301, but may be physically adsorbed on the surface of the nucleation layer 301 in some embodiments.

Returning to FIG. 2B, in operation 284, the chamber is purged. By this purge operation, excess H ₂ remaining in the gas phase can be removed. Purge is performed by reducing the chamber pressure by flowing an inert gas at a constant pressure and repressurizing the chamber before initiating exposure to another gas. The chamber may be purged for any suitable duration, for example for a duration of between about 0.1 seconds and about 3 seconds. Operation 284 of FIG. 2B may correspond to purge phase 240A of FIG. 2C. As shown in FIG. 2C, during the purge phase 240A, the carrier gas is introduced while the H ₂ and WF ₆ flows are turned off. FIG. 3B shows that H ₂ (311a and 311b in FIG. 3A), which has been in the gas phase, is purged from the chamber, and H ₂ (313a and 313b) that has been on the surface so far is formed on the surface of the tungsten nucleation layer 301. An example of staying is presented.

Returning to FIG. 2B, in operation 286, the substrate is exposed to a tungsten-containing precursor (eg, WF ₆ ) to form a sub-atomic layer of the film on the substrate. In various embodiments, this operation causes WF ₆ to flow into the chamber for a duration of between about 0.1 seconds to about 3 seconds, or about 0.5 seconds. In some embodiments, WF ₆ can be diverted for pre-dose gas line filling and line change. In some embodiments, WF ₆ is flowed into the chamber but does not react completely with all H ₂ molecules on the substrate surface. Operation 286 may correspond to WF ₆ dose 260A in FIG. 2C. As shown in FIG. 2C, during the WF ₆ dose 260A, the carrier gas is introduced, the H ₂ flow is turned off, and the WF ₆ flow is turned on.

FIG. 3C shows a schematic example for operation 286 of FIG. 2B. In Figure 3C, the substrate is exposed to WF _6, a portion of WF _6, a gas phase (331a and 331b), a portion of WF _6, in the substrate or near the surface (323a and 323b).

In operation 286 of FIG. 2B, some WF ₆ may react with H ₂ remaining on the surface from the previous dose. As shown in FIG. 3D, WF ₆ can react with H ₂ , thereby temporarily forming intermediate 343b, whereby in FIG. 3E, intermediate 343b completely reacts to form the surface of substrate 300. Above this, tungsten 390 remains on the nucleation layer 301 and HF remains in the vapor phase (eg, 351a and 351b).

In operation 286 of FIG. 2B, some WF ₆ may not react completely with H ₂ remaining on the surface from the previous dose. As shown in FIG. 3D, WF ₆ can partially react with H ₂ to form intermediate 343a, which in FIG. 3E allows the surface of substrate 300 to remain partially reacted with intermediate 343a. It remains on the nucleation layer 301 above. The reaction mechanism involving WF ₆ and H ₂ may be slower than the reaction of borane or silane or germane with WF _{6 in} the case of tungsten nucleation layer deposition due to activation energy barriers and steric hindrance effects. is there. For example, without being bound by a particular theory, WF ₆ stoichiometry can use at least three H ₂ molecules to react with one WF ₆ molecule. WF ₆ does not form tungsten, but may partially react with H ₂ molecules to form an intermediate. For example, this is based on stoichiometric principles (eg, using three H ₂ molecules to react with one WF ₆ molecule), enough H ₂ to react with WF ₆ is in the vicinity. The intermediate 343a remains on the substrate surface.

In operation 286 of FIG. 2B, some WF ₆ may not react at all with H ₂ , but instead on the substrate surface when there is no physisorbed H ₂ or remaining H ₂ on the substrate surface. , WF ₆ can be physically adsorbed. In some embodiments, WF ₆ may remain on the substrate surface, but may not be physisorbed or chemisorbed on the surface.

  Operation 286 of FIG. 2B can thereby form a tungsten sub-atomic layer in a number of embodiments. For example, after performing operations 282-286, a subatomic layer of about 0.3 mm thickness may be deposited.

In operation 288 of FIG. 2B, the chamber is purged to remove gas phase reaction byproducts and WF ₆ from the chamber. In some embodiments, the purge duration in operation 288 may be too short to increase non-sequential CVD reactivity, thereby depositing a higher stress film. In some embodiments, the purge duration is between about 0.1 seconds and about 2 seconds, and according to this purge duration, the WF ₆ adsorption rate to the tungsten surface is reduced from the substrate surface. It can be avoided that all WF ₆ is removed. In some embodiments, the purge duration is between about 0.1 seconds and about 15 seconds, for example about 7 seconds. For example, in the case of manufacturing a 3D NAND structure, the chamber may be purged in operation 288 for about 7 seconds. The purge duration depends on the substrate and the stress.

  Operation 288 of FIG. 2B may correspond to purge phase 270A of FIG. 2C. As shown in FIG. 2C, in the purge phase 270A, the deposition cycle 211A is complete. FIG. 3F provides a schematic example of a substrate when purging the chamber. It is noted that compound 343c can be an intermediate formed without complete reaction, while some tungsten 390 can be formed on the substrate. Each cycle thereby forms a sub-atomic layer of tungsten on the substrate.

  In some embodiments, operations 286 and 282 may be reversed so that operation 286 is performed prior to operation 282. In some embodiments, operation 282 may be performed before operation 286.

In operation 290 of FIG. 2B, it is determined whether bulk tungsten has been deposited to an appropriate thickness. If not, operations 282 to 288 are repeated until the desired thickness is deposited. In some embodiments, operations 282 to 288 are repeated until the feature is filled. In FIG. 2C, it is determined that bulk tungsten has not been deposited to the proper thickness, and therefore operations 282-288 of FIG. 2B are repeated in deposition cycle 211B, thereby executing H ₂ dose 220B, Subsequently, the purge phase 240B is executed. A WF ₆ dose 260B is performed, followed by another purge phase 270B.

As an example, FIG. 3G illustrates operation 282 in a repetitive cycle, whereby vapor phase H ₂ 311c is incorporated into a substrate having deposited tungsten 390 and partially reacted intermediate 343d thereon. It is. It should be noted that the incorporated H ₂ can be completely reacted with the intermediate 343d on the substrate at this time, and as a result, as shown in FIG. 3H, by the reacted compound 343d. Deposited tungsten 390b and 390c are left, and by-products HF351c and 351d are formed in the gas phase. Some H ₂ 311c may remain in the gas phase while some H ₂ 313c may remain on the tungsten layer 390a. In FIG. 3I, the chamber is purged (this corresponds to operation 284 of FIG. 2B or operation 240B of FIG. 2C), leaving the deposited tungsten 390a, 390b, 390c and some H ₂ 313c. In FIG. 3J, WF ₆ is again introduced at a dose, at which time molecules 331c and 323c can adsorb and / or react with H ₂ and the substrate. FIG. 3J may correspond to operation 286 in FIG. 2B or 260B in FIG. 2C. After the WF ₆ dose, the chamber may be purged again and the cycle may be repeated again until the desired thickness of tungsten is deposited.

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

FIG. 3K presents a process flow diagram for a method performed in accordance with the disclosed embodiments. In operation 280, bulk tungsten is deposited by sequential CVD. The process conditions and chemistry can be any of those described above with respect to FIGS. 2B and 3A-3J. In operation 299, bulk tungsten is deposited by non-sequential CVD. In non-sequential CVD, the substrate is simultaneously exposed to a tungsten-containing precursor and a reducing agent to deposit a bulk. Examples of tungsten-containing precursors include fluorine-containing precursors (eg, WF ₆ ), chlorine-containing precursors (eg, WCl _x ), and hexacarbonyl tungsten (W (CO) ₆ ). Examples of the reducing agent include hydrogen. In some embodiments, non-sequential CVD deposition is by exposing the substrate to WF ₆ and H ₂ . Operations 280 and 299 may be performed sequentially, or any of operations 280 may be performed one or more times before or after execution of operation 299. In some embodiments, operations 280 and 299 are performed in pulses, so that operation 299 is performed for every execution of two or more cycles of operation 280. In this way, bulk tungsten can be deposited using a combination of sequential and non-sequential CVD.

The disclosed embodiments can have a variety of applications in tungsten deposition processes. For example, in some embodiments, a tungsten nucleation layer is deposited by an ALD cycle of alternating pulses of reducing agent (eg, borane, silane, or germane) and WF ₆ , followed by as described above with respect to FIG. 2B. The feature may be filled by depositing bulk tungsten by sequential CVD.

In another example, in some embodiments, an ALD cycle of a reducing agent and WF ₆ is used to deposit a tungsten nucleation layer followed by a reducing agent and a fluorine-free tungsten-containing precursor (eg, an organometallic tungsten precursor). The bulk tungsten may be deposited by a combination of fluorine-free tungsten CVD using a body and sequential CVD as described above with respect to FIG. 2B. The fluorine-free tungsten precursor may further include carbonyl tungsten (W (CO) ₆ ) and tungsten chloride (WCl _x ) such as tungsten pentachloride (WCl ₅ ) and tungsten hexachloride (WCl ₆ ).

In another example, a tungsten nucleation layer may be deposited on the feature by an ALD cycle of alternating pulses of reducing agent and WF ₆ , and alternating between sequential and non-sequential CVD as described above with respect to FIG. 2B. The bulk tungsten may be deposited by repeating the above. For example, bulk tungsten can be deposited using several cycles of sequential CVD between non-sequential CVDs of a predetermined duration. In a specific example, bulk tungsten may be deposited using about 5 cycles of sequential CVD followed by 5 seconds of non-sequential CVD followed by 5 cycles of sequential CVD and then 5 seconds of non-sequential CVD.

In another example, a tungsten nucleation layer is first deposited by an ALD cycle of alternating pulses of reducing agent and WF ₆ , then partially filled with features using sequential CVD, and further by non-sequential CVD. The feature may be filled by filling the rest of the feature.

In another example, a tungsten nucleation layer is deposited by an ALD cycle of alternating pulses of reducing agent and WF ₆ followed by partial deposition of bulk tungsten by sequential CVD, and further (using an organometallic tungsten precursor). The feature may be filled by complete bulk filling with fluorine-free tungsten CVD. For example, in order to partially fill the feature by the bulk tungsten, some performed sequentially CVD cycles, followed by MDNOW the remaining portion of the feature by CVD using simultaneous exposure to H ₂ may be filled . It should be noted that in some embodiments, the features can be filled without depositing a nucleation layer, but the nucleation layer can help to slow down the growth of bulk tungsten.

It should be understood that various combinations of the applications described herein may be used to deposit tungsten, and that the methods are not limited to the examples presented herein. Let's go. For example, instead of WF ₆ in the embodiment described herein, or in combination with WF _6, chlorine-containing tungsten precursors such as five tungsten chloride (WCl ₅₎ and tungsten hexachloride (WCl ₆₎ (WCl _x ) May be used.

In various embodiments, a soak or surface treatment operation may be performed prior to depositing the nucleation layer. Examples of soak or surface treatment include silane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), germane (GeH ₄ ), argon (Ar), tungsten hexafluoride (WF ₆ ), Exposing the substrate to a gas of diborane (B ₂ H ₆ ), hydrogen (H ₂ ), nitrogen (N ₂ ), or a combination thereof includes. In some embodiments, the substrate can be soaked with one or more gases. For example, in some embodiments, the substrate may be exposed to silane for a first duration and then to diborane for a second duration. Such an operation may be repeated in a cycle. In another example, the substrate may be exposed to diborane for a first duration and then exposed to silane for a second duration. In another example, the substrate may be exposed to diborane for a first duration and then exposed to hydrogen for a second duration. In another example, the substrate may be exposed to silane for a first duration and then exposed to hydrogen for a second duration. In some embodiments, the substrate may be exposed to nitrogen gas in combination with any of the above soak processes. In any of the disclosed embodiments, the chamber containing the substrate may be purged between one or more soak operations. Purging can be performed by flowing an inert gas such as argon into the chamber. For example, in one example, the substrate may be exposed to diborane for a first duration, the chamber may then be purged, and then the substrate may be exposed to silane for a second duration.

Prior to depositing the bulk tungsten layer, the nucleation layer deposited according to some disclosed embodiments includes a tungsten-containing precursor and silane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), germane (GeH ₄ ), or a reducing agent such as diborane (B ₂ H ₆ ) may be used alternately for deposition. In some embodiments, the nucleation layer is deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and silane. In some embodiments, the nucleation layer is deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane. In some embodiments, the nucleation layer is deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and silane, and then exposing the substrate to alternating pulses of tungsten-containing precursor and diborane. The In some embodiments, the nucleation layer is deposited by exposing the substrate to alternating pulses of tungsten-containing precursor and diborane, and then exposing the substrate to alternating pulses of tungsten-containing precursor and silane. The In some embodiments, the nucleation layer exposes the substrate to alternating pulses of tungsten-containing precursor and silane, and then exposes the substrate to alternating pulses of tungsten-containing precursor and diborane, followed by tungsten. Deposited by exposing the substrate to alternating pulses of containing precursor and silane. In some embodiments, the nucleation layer exposes the substrate to alternating pulses of tungsten-containing precursor and diborane, and then exposes the substrate to alternating pulses of tungsten-containing precursor and silane, followed by tungsten. Deposited by exposing the substrate to alternating pulses of containing precursor and diborane. In any of the disclosed embodiments, the chamber containing the substrate may be purged between one or more dose operations to deposit the nucleation layer. Purging can be performed by flowing an inert gas such as argon into the chamber. Any suitable inert gas may be used for the purge. For example, in some embodiments, the substrate may be exposed to a pulse of a tungsten-containing precursor, then the chamber may be purged, and then the substrate may be exposed to a pulse of silane, and the chamber is purged again. In addition, such an operation may be repeated in a cycle.

The deposition of a nucleation layer that can be used in any of the above implementations is during the nucleation deposition process, or during a silane dose, or during a diborane dose, or of a tungsten-containing precursor such as a WF ₆ dose. Co-flowing any one of hydrogen (H ₂ ), argon (Ar), nitrogen (N ₂ ), or a combination thereof during dose or during any purge time. Good. In some embodiments, exposing the substrate to any of silane, disilane, trisilane, germane, diborane, hydrogen, tungsten hexafluoride, nitrogen, argon, and combinations thereof during or after nucleation growth A surface treatment operation may be performed. For example, during deposition of the nucleation layer, the substrate may be exposed to alternating pulses of silane and WF ₆ , then the substrate may be exposed to silane soak, and then to alternating pulses of silane and WF ₆ . The substrate exposure may be resumed. Such operations may be performed in cycles. For example, in some embodiments, the following cycle may be repeated one or more times to deposit a nucleation layer: alternating pulses of SiH ₄ and WF ₆ and exposure to a surface treatment.

In some embodiments, the nucleation layer is a substrate containing any combination of a tungsten-containing precursor and one or more of the following gases, sequentially in any order, and in one or more cycles. Can be deposited by exposure: diborane, silane, disilane, trisilane, hydrogen, nitrogen, and germane (GeH ₄ ). For example, in some embodiments, the nucleation layer can be deposited by exposing the substrate to diborane, exposing the substrate to tungsten hexafluoride, exposing the substrate to silane, and exposing the substrate to hydrogen. . Such an operation may be repeated in one or more cycles. In another example, in some embodiments, the nucleation layer can be deposited by exposing the substrate to silane, exposing the substrate to tungsten hexafluoride, and exposing the substrate to hydrogen. Such an operation may be repeated in one or more cycles. In another example, in some embodiments, the nucleation layer can be deposited by exposing the substrate to diborane, exposing the substrate to hydrogen, and exposing the substrate to tungsten hexafluoride. Such an operation may be repeated in one or more cycles. In another example, in some embodiments, the nucleation layer can be deposited by exposing the substrate to nitrogen, exposing the substrate to diborane, and exposing the substrate to tungsten hexafluoride. Such an operation may be repeated in one or more cycles. In another example, in some embodiments, the nucleation layer can be deposited by exposing the substrate to silane, exposing the substrate to nitrogen, and exposing the substrate to tungsten hexafluoride. Such an operation may be repeated in one or more cycles. In any of the described embodiments, any available gas may be used to expose the substrate to surface treatment and / or soak operations before, during, or after the nucleation deposition cycle. In some embodiments, additional gas may be co-flowed with any of the above gases during one or more exposures of the nucleation deposition process. In any of the disclosed embodiments, the chamber containing the substrate may be purged between one or more dose operations to deposit the nucleation layer. Purging can be performed by flowing an inert gas such as argon into the chamber. Any suitable inert gas may be used for the purge.

Bulk tungsten deposition is disclosed herein and disclosed embodiments described in US patent application Ser. No. 14 / 723,275 filed May 27, 2015 (Attorney Docket LAMRP 183 / 3623-1 US). The above references are incorporated herein by reference in their entirety. Also, in any of the above implementations, bulk tungsten is deposited periodically with renucleation and / or soaking and / or surface treatment and / or conventional CVD deposition operations performed between bulk depositions. May be. For example, in some embodiments, the disclosed embodiments as described above with respect to FIG. 2B may be used to deposit bulk tungsten, after which bulk tungsten deposition may be paused and then the surface of the substrate The substrate may be exposed to alternating pulses of silane and WF ₆ , or diborane and WF ₆ , and then the bulk tungsten using the disclosed embodiments as described above with respect to FIG. 2B. The deposition may be resumed. Such an operation may be repeated for any number of cycles. In another example, in some embodiments, bulk tungsten may be deposited using the disclosed embodiments as described above with respect to FIG. 2B, after which bulk tungsten deposition may be paused, To treat the surface of the substrate, the substrate is subjected to soaking or surface treatment by flowing one of silane, disilane, trisilane, germane, diborane, hydrogen, tungsten hexafluoride, nitrogen, argon, and combinations thereof. The exposure may then be performed and then the deposition of bulk tungsten may be resumed using the disclosed embodiments as described above with respect to FIG. 2B. Bulk tungsten deposition may be performed by exposing the substrate to a tungsten-containing precursor such as WF ₆ and one or more of the following gases: hydrogen, silane, disilane, trisilane, diborane, nitrogen, argon , And germane. Also, as described above with respect to FIG. 3K, bulk tungsten may be deposited using sequential CVD and conventional CVD in combination. Conventional CVD may be performed before, during (eg, by sequentially repeating CVD and conventional CVD), or after depositing bulk tungsten using sequential CVD.

In some embodiments, the substrate may be annealed at any suitable temperature before depositing the bulk tungsten and after depositing the nucleation layer. In some embodiments, the substrate may be annealed at any suitable temperature after depositing the bulk tungsten layer. In some embodiments, the substrate may be annealed at any suitable temperature at an intermediate point during bulk tungsten deposition. Annealing may be performed in any suitable gas environment, such as an environment containing one or more of the following gases: a tungsten-containing gas such as WF ₆ , hydrogen, silane, disilane, trisilane, diborane, nitrogen, argon, and germane.

In various embodiments, the chamber containing the substrate is evacuated or purged before or after the tungsten-containing precursor and reducing agent dose for depositing bulk tungsten according to the disclosed embodiments as described above with respect to FIG. 2B. You can do it. In some embodiments, a delay time may be introduced into the dose or purge step of sequential CVD deposition as described herein. In some embodiments, one or more gases may be co-flowed during a dose or purge operation using any one or more of the following gases: WF ₆ , hydrogen, silane, disilane, trisilane, diborane. , Nitrogen, argon, and germane.

  The temperature of the substrate during nucleation deposition may not be the same as the temperature of the substrate during sequential CVD as described above with respect to FIG. 2B. The temperature of the substrate is taken to mean the temperature set on the table holding the substrate. The disclosed embodiments may be performed at any suitable pressure, such as a pressure greater than about 10 Torr, or a pressure less than about 10 Torr. In the case of a multi-station chamber, each platform may be set to a different temperature. In some embodiments, each platform is set to the same temperature. During some or all of the above operations according to the disclosed embodiments, the substrate may be cycled from station to station. The chamber pressure may also be modulated in one or more operations in some disclosed embodiments. In some embodiments, the chamber pressure during nucleation deposition is different from the chamber pressure during bulk deposition. In some embodiments, the chamber pressure during nucleation deposition is the same as the chamber pressure during bulk deposition.

In any of the above exposures, the gas may be pulsed or flowed continuously. For example, in some embodiments, during sequential CVD operation WF ₆ doses, WF ₆ may be pulsed one or more times during a single dose. Similarly, in some embodiments, during purging, the inert gas may be pulsed one or more times during a single purge operation. Such a pulsing operation may be performed in any nucleation deposition operation, or any bulk deposition operation, or any combination thereof. In some embodiments, one or more changes may be made to one or more parameters such as pressure, flow rate, and temperature. In some embodiments, the pedestal may be moved so that the spacing between the substrate and the showerhead above the pedestal can be modulated during either nucleation deposition or bulk deposition or both operations. . The movement of the platform may be used in combination with changing one or more parameters such as pressure, temperature, or flow rate. Modulating the spacing between the substrate and the showerhead can affect the pressure, temperature, or flow rate that can be used in accordance with some disclosed embodiments. It will be appreciated that any of the processes described herein may be applicable to technologies involving ALD.

[apparatus]
Any suitable chamber may be used to implement the disclosed embodiments. Examples of deposition equipment include various systems such as ALTUS® and ALTUS® Max available from Lam Research Corp., Fremont, California, or various other Any of the commercially available processing systems are included. In some embodiments, sequential chemical vapor deposition (CVD) is a first station that is one of two, five, or more deposition stations disposed within a single deposition chamber. Can be implemented. In that case, at the first station, for example, hydrogen (H ₂ ) and tungsten hexafluoride (WF ₆ ) are alternately applied to the surface of the semiconductor substrate using individual gas supply systems that generate a local atmosphere on the substrate surface. May be introduced. Other stations may be used for fluorine-free tungsten deposition or non-sequential CVD. Other stations may be used to deposit the tungsten nucleation layer at low pressure. More than one station may be used to deposit tungsten in parallel processing. Alternatively, the wafer may be indexed so that sequential CVD operations are performed sequentially across two or more stations.

  FIG. 4 is a block diagram of a processing system suitable for performing a tungsten thin film deposition process in accordance with some embodiments. The system 400 includes a transfer module 403. The transfer module 403 provides a clean pressurized environment to minimize the risk of substrate contamination when transferring the substrate being processed between several reactor modules. A multi-station reactor 409 capable of performing atomic layer deposition (ALD) and sequential CVD according to some embodiments is attached to the transfer module 403. Multi-station reactor 409 may also be used to perform fluorine-free tungsten deposition and / or non-sequential CVD in some embodiments. The reactor 409 may have a plurality of stations 411, 413, 415, 417 that may perform operations sequentially according to the disclosed embodiments. For example, the reactor 409 may perform nucleation layer deposition by ALD at station 411, perform sequential CVD at station 413, perform fluorine-free tungsten deposition at station 415, and perform non-sequential CVD at station 417. It can be configured. These stations may have a heated platform or substrate support and one or more gas inlets or showerheads or dispersion plates. An example of a deposition station 500 is shown in FIG. 5, which has a substrate support 502 and a showerhead 503. A heater may be provided on the base portion 501.

  In addition, one or more single or multi-station modules 407 that can perform plasma or chemical (non-plasma) pre-cleaning may be attached to the transfer module 403. The module may also be used in various processes, for example to prepare a substrate for a deposition process. The system 400 further comprises one or more wafer source modules 401 for storing pre-processed and post-processed wafers. First, a wafer may be taken out from the source module 401 to the load lock 421 by an atmospheric robot (not shown) in the atmospheric transfer chamber 419. A wafer is transferred from the load lock 421 to a module attached to the transfer module 403 by a wafer transfer device (generally, a robot arm unit) in the transfer module 403, and between the modules attached to the transfer module 403. Transport.

  In various embodiments, a system controller 429 is employed to control process conditions during deposition. The controller 429 generally comprises one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, and the like.

  Controller 429 may control all of the operation of the deposition apparatus. The system controller 429 provides a set of instructions for controlling specific process timing, gas mixing, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power level, wafer chuck or platform position, and other parameters. Run the system control software that contains it. Other computer programs stored in a memory device associated with controller 429 may be employed in some embodiments.

  In general, a user interface associated with the controller 429 is provided. User interfaces may include display screens, graphical software displays of equipment and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, and the like.

  The 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 for controlling the drive circuit may be hard coded or provided as software. Those instructions may be provided by “programming”. Such programming can be any form of logic, such as hard-coded logic in digital signal processors, application-specific integrated circuits, and other devices, with specific algorithms implemented as hardware. It is interpreted as including. Programming is further interpreted as including software or firmware instructions that may be executed on a general purpose processor. The system control software can be coded in any suitable computer readable programming language.

  Computer program code for controlling germanium-containing reducing agent pulses, hydrogen flow, and tungsten-containing precursor pulses, and other processes in the process sequence is, for example, an ordinary computer such as assembly language, C, C ++, Pascal, Fortran, etc. Can be created in any readable programming language. The task indicated by the program is executed by executing the compiled object code or script by the processor. Further, as pointed out, the program code may be hard coded.

  The controller parameters relate to process conditions such as process gas composition and flow rate, temperature, pressure, cooling gas pressure, substrate temperature, chamber wall temperature, and the like. These parameters are provided to the user in the form of a recipe and can be entered utilizing a user interface.

  Signals for monitoring the process may be provided by system controller 429 analog and / or digital input connections. Signals for controlling the process are output to the analog and digital output connections of the deposition apparatus 400.

  The system software can be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be created to control the operation of the chamber components necessary to perform the deposition process according to the disclosed embodiments. Examples of programs or program parts for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

  In some implementations, the controller 429 is part of a system that can be part of the above example. Such systems include semiconductors such as processing tools or some tools, chambers or some chambers, processing platforms or some platforms, and / or certain processing components (wafer platforms, gas flow systems, etc.) A processing device may be provided. These systems may be integrated with electronic devices to control their operations before, during and after processing of the semiconductor wafer or substrate. These electronic devices may refer to the above “controllers” that may control various components or subparts of the system or several systems. The controller 429 may provide process gas supply, temperature settings (eg, heating and / or cooling), pressure settings, vacuum settings, power settings, high frequency (RF) in some systems, depending on processing requirements and / or system type. ) Generator settings, RF matching circuit settings, frequency settings, flow settings, fluid supply settings, position and operation settings, between tools and with other transport tools and / or to connect to or interface to a specific system Can be programmed to control any process disclosed herein, including wafer transfer to and from a load lock.

  The controller broadly refers to various integrated circuits, logic, memory, and / or software that receives instructions, issues instructions, controls operations, implements cleaning operations, implements endpoint measurements, etc. It can be defined as an electronic device having. The integrated circuit executes a chip in the form of firmware storing program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or program instructions (eg, software). One or more microprocessors or microcontrollers may be included. Program instructions are in the form of various individual settings (or program files) that define operating parameters for performing a specific process on a semiconductor wafer or a specific process or system for a semiconductor wafer. It can be a command transmitted to the controller. Operating parameters, in some embodiments, enable one or more processing steps in the manufacture of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer. To be part of a recipe defined by a process engineer.

  The controller 429 is, in some implementations, part of a computer that is integrated or connected to the system, or otherwise networked to the system, or that is connected to such a computer. There may be or a combination thereof. For example, the controller 429 may be in the “cloud” or may be all or part of a fab host computer system, which may allow remote access for wafer processing. The computer monitors the current progress of manufacturing operations, examines the history of past manufacturing operations, investigates trends or performance metrics from multiple manufacturing operations, changes current processing parameters, Remote access to the system can be implemented to set up the processing steps according to the process or to start a new process. In some examples, a remote computer (eg, a server) can provide process recipes to the system over a network that can include a local network or the Internet. The remote computer may have a user interface that allows entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data specifying parameters for each of the process steps performed in one or more operations. It should be understood that these parameters may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. In that case, as described above, such as by including one or more separate controllers that are networked together and cooperate towards a common purpose such as the processes and controls described herein, etc. Controllers may be distributed. One example of a distributed controller for such purposes is one or more integrated circuits mounted in a chamber, which are one or more remotely located (such as at the platform level or as part of a remote computer). Communicate with integrated circuits and jointly control processes in the chamber.

  Exemplary systems include, but are not limited to, plasma etch chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, clean chambers or modules, bevel edge etch chambers or modules, physical Vapor Deposition (PVD) Chamber or Module, CVD Chamber or Module, ALD Chamber or Module, Atomic Layer Etch (ALE) Chamber or Module, Ion Implantation Chamber or Module, Track Chamber or Module, and Semiconductor Wafer Fabrication and / or Manufacturing And any other semiconductor processing system that may be associated with or used.

  As described above, depending on the processing steps or some steps performed by the tool, the controller may have other tool circuits or modules, other tool parts, cluster tools, other tool interfaces, neighboring tools, neighboring tools, Of tools, tools located throughout the factory, main computers, other controllers, or tools used in material transport to move wafer containers between tool locations and / or load ports in semiconductor manufacturing plants Can communicate with one or more of them.

  The controller 429 can include various programs. The substrate positioning program is used to load the substrate onto a platform or chuck, and also to control the spacing between the substrate and other members of the chamber such as gas inlets and / or targets. Program code may be included for controlling the chamber components. The process gas control program includes code for controlling gas composition, flow rate, pulse time, and optionally for flowing gas into the chamber to stabilize the pressure in the chamber prior to deposition. obtain. The pressure control program may include code for controlling the pressure in the chamber, for example, by adjusting the throttle valve of the chamber exhaust system. The heater control program may include code for controlling the current to the heating unit that is used to heat the substrate. Alternatively, the heater control program may control supply of a heat transfer gas such as helium to the wafer chuck.

  Examples of chamber sensors that can be monitored during deposition include a mass flow controller, a pressure sensor such as a manometer, a thermocouple located on a table or chuck. Appropriately programmed feedback and control algorithms may be used with the data from these sensors to maintain the desired process conditions.

  The above describes the implementation of the disclosed embodiments in a single or multi-chamber semiconductor processing tool. The apparatus and processes described herein may be used in combination with lithographic patterning tools or processes, for example, for making or manufacturing semiconductor devices, displays, LEDs, solar panels, and the like. In general, such tools / processes, although not necessarily, are used or performed together in a common manufacturing facility. Lithographic patterning of the film typically includes some or all of the following steps, each step being performed using several possible tools. (1) Apply photoresist on workpiece or substrate using spin or spray tool; (2) Cure photoresist using hot plate or oven or UV curing tool; (3 ) Expose the photoresist with visible light, ultraviolet light or X-rays with a tool such as a wafer stepper; (4) Use a tool such as a wet bench to develop the resist to selectively remove the resist, thereby Form a pattern; (5) transfer the resist pattern to the underlying film or workpiece using a dry or plasma assisted etching tool; (6) use a tool such as an RF or microwave plasma resist stripper; Strip the resist.

[Experiment]
“Experiment 1”
Experiments were conducted on four processes for depositing bulk tungsten at 395 ° C. and a pressure of 40 Torr. In each process, bulk tungsten is deposited on a tungsten nucleation layer deposited using atomic layer deposition (ALD) in which alternating cycles of diborane (B ₂ H ₆ ) and tungsten hexafluoride (WF ₆ ) are repeated. I let you. FIG. 6 presents an exemplary pulsing scheme for each of these four processes. In process 1, as in conventional chemical vapor deposition (CVD), H ₂ and WF ₆ are flowed continuously into the chamber simultaneously. In process 2, WF ₆ is pulsed (eg, pulsed CVD) while H ₂ is continuously flowing. In process 3, WF ₆ is continuously introduced while H ₂ is pulsed (eg, pulsed CVD). In process 4, H ₂ and WF ₆ are alternately pulsed using a method as described above with respect to FIG. 2B (eg, sequential CVD). The thickness of the tungsten nucleation layer and the stress, non-uniformity, and resistivity of the films deposited using each of these four processes were measured and compiled in Table 1 below.

  As shown in Table 1, both the stress and resistivity of the tungsten film deposited using Process 4 are significantly lower than the film deposited using any of Processes 1-3.

"Experiment 2"
Bulk tungsten is deposited on two substrates, both of which have a titanium nitride (TiN) barrier layer and a tungsten nucleation layer deposited by ALD that repeats alternating cycles of B ₂ H ₆ and WF _6. Experiments were conducted on the process to make it happen. One substrate involved bulk tungsten deposition using non-sequential CVD with simultaneous exposure of the substrate to WF ₆ and H ₂ at 300 ° C. The other substrate is involved in bulk tungsten deposition using sequential CVD as described above with respect to FIG. 2B, with repeated alternating WF ₆ and H ₂ pulses 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 FIG.

  Line 700 shows the fluorine concentration for a substrate having tungsten deposited by non-sequential CVD. Line 701 shows the fluorine concentration for a substrate having tungsten sequentially deposited by CVD. A line at the W / TiN interface at about 350 mm represents the interface between the tungsten nucleation layer and the TiN barrier layer. The dotted line at the TiN / oxide interface at about 475 mm 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 plot is due to orders of magnitude, and the sequential CVD fluorine concentration 701 is significantly lower than the non-sequential CVD fluorine concentration 700, and several substrates. This means that the fluorine concentration is up to two orders of magnitude lower in depth.

“Experiment 3”
Experiments were conducted on a process for depositing bulk tungsten on a substrate at different pressures. Each of the three substrates had a TiN barrier layer.
One substrate is deposited by tungsten nucleation layer deposited by ALD repeating alternating cycles of B ₂ H ₆ and WF ₆ at 10 Torr, followed by exposure of the substrate to WF ₆ and H ₂ at 300 ° C. Is involved in CVD of bulk tungsten. Another substrate repeats the deposition of a tungsten nucleation layer deposited by ALD, repeating alternating cycles of B ₂ H ₆ and WF ₆ at 10 Torr, followed by alternating pulses of WF ₆ and H ₂ at 10 Torr. This is related to the sequential CVD of bulk tungsten. The third substrate uses an ALD of tungsten nucleation layer deposited by repeating alternating cycles of B ₂ H ₆ and WF ₆ at 3 Torr, followed by alternating pulses of WF ₆ and H ₂ at 10 Torr. This was related to the sequential CVD of bulk tungsten. The fluorine concentration was measured for all three substrates. Table 3 shows the conditions for this experiment. The results are plotted in FIG.

  Line 800 represents the fluorine concentration for the first substrate on which bulk tungsten is deposited by non-sequential CVD. Dashed line 801 represents the fluorine concentration for the second substrate on which bulk tungsten was deposited sequentially by CVD following deposition of the nucleation layer at 10 Torr. Dotted line 803 represents the fluorine concentration for a third substrate on which bulk tungsten was deposited sequentially by CVD following deposition of the nucleation layer at 3 Torr. The result is that in sequential CVD (803) following the nucleation layer at low pressure, the second substrate (801) at the W / TiN interface or even at the TiN layer (between 350 and 475). It indicates that a lower fluorine concentration was shown. This suggests that the diffusion of fluorine into the TiN layer and oxide can be reduced by reducing the fluorine concentration in the tungsten film.

“Experiment 4”
Experiments were conducted on a process for depositing bulk tungsten on a substrate using different combinations of tungsten deposition. Comparison was made with three substrates. One substrate consists of an 18 K tungsten nucleation layer deposited at 3 Torr using an ALD that repeats alternating pulses of 1 K K thermal oxide, 30 K TiN, alternating WF ₆ and B ₂ H ₆ , WF ₆ , And bulk tungsten deposited at 10 Torr using sequential CVD with H ₂ pulses. The fluorine concentration of this substrate is indicated by a broken line 912 in FIG. The other substrate was 12 K tungsten deposited at 3 Torr using ALD with repeating alternating pulses of 1 K thermal oxide, 30 K TiN, 10 K fluorine free tungsten, and WF ₆ and B ₂ H _6. It had a nucleation layer and bulk tungsten deposited by sequential CVD at 10 Torr using WF ₆ and H ₂ pulses. The fluorine concentration of the second substrate is indicated by a line 911 in FIG. The third substrate is a 12 タ ン グ ス テ ン tungsten nucleation layer deposited at 3 Torr using an ALD that repeats alternating pulses of WF ₆ and B ₂ H ₆ with oxide from 5 k Å TEOS deposition, 30 フ ッ 素 fluorine-free tungsten, and WF ₆ and B ₂ H _6. And bulk tungsten deposited by sequential CVD at 10 Torr using WF ₆ and H ₂ . The fluorine concentration of this substrate is indicated by a dotted line 913 in FIG. The layers deposited on each substrate in this experiment are summarized in Table 4.

  As shown in FIG. 9, there was less fluorine diffusion at the fluorine concentration for films deposited using a combination of fluorine-free tungsten, low pressure nucleation layers, and sequential CVD (W / TiN interface). (See line 911 and line 913 at depths greater than 425 mm beyond). The fluorine concentration near the nucleation layer was lowest between 300 and 425% for films with more fluorine-free tungsten deposited on the substrate, whereas bulk tungsten has a fluorine-free tungsten layer. In the case of films deposited using low pressure nucleation and sequential CVD without lowering, the fluorine concentration was lower between about 50% and 300% (see line 912). These results suggest that the combination of fluorine-free tungsten deposition and sequential CVD of tungsten may result in a tungsten film that achieves a very low fluorine concentration and reduced fluorine diffusion. Yes.

"Experiment 5"
Experiments were carried out on the process of depositing films sequentially by CVD in combination with low pressure and high pressure nucleation layer deposition. One substrate uses a tungsten nucleation layer deposited using ALD that repeats alternating cycles of WF ₆ and B ₂ H ₆ at 10 Torr and the above described pulse using alternating pulses of WF ₆ and H ₂ at 10 Torr. As shown in FIG. 2B, bulk tungsten deposited by sequential CVD according to FIG. 2B. Film stress and resistivity measured at several thickness locations are shown as lines 1001 “low pressure nucleation” in FIGS. 10A and 10B. The other substrate is a tungsten nucleation layer deposited using ALD that repeats alternating cycles of WF ₆ and B ₂ H ₆ at 40 Torr, and alternating pulses of WF ₆ and H ₂ at 10 Torr, as described above. As shown in FIG. 2B, bulk tungsten deposited by sequential CVD according to FIG. 2B. Film stress and resistivity measured at several thickness locations are shown in FIGS. 10A and 10B as line 1002 “nucleation at high pressure”. The deposition conditions for these nucleation layers and bulk layers are shown in Table 5.

  As shown in the results, the substrate with the nucleation layer deposited at low pressure was significantly less stressed than the substrate with the nucleation layer deposited at high pressure, while the resistivity was It remained almost the same.

“Experiment 6”
Experiments were conducted on the process of depositing films sequentially by CVD in combination with low temperature and high temperature nucleation layer deposition. One substrate uses a tungsten nucleation layer deposited using ALD that repeats alternating cycles of WF ₆ and B ₂ H ₆ at 10 Torr and 250 ° C., and using alternating pulses of WF ₆ and H ₂ at 10 Torr. And bulk tungsten deposited by sequential CVD according to FIG. 2B as described above. Film stress and resistivity measured at several thickness locations are shown in FIGS. 11A and 11B as line 1102 “low temperature nucleation”. The other substrate is a tungsten nucleation layer deposited using ALD that repeats alternating cycles of WF ₆ and B ₂ H ₆ at 10 Torr and 300 ° C., and using alternating pulses of WF ₆ and H ₂ at 10 Torr. And bulk tungsten deposited by sequential CVD according to FIG. 2B as described above. Film stress and resistivity measured at several thickness locations are shown as lines 1102 “high temperature nucleation” in FIGS. 11A and 11B. The deposition conditions for these nucleation layers and bulk layers are shown in Table 6.

  As shown in the results, the substrate with a nucleation layer deposited at a low temperature was significantly less stressed than the substrate with a nucleation layer deposited at a high temperature, whereas it deposited at a higher temperature. The resistivity of the deposited film was slightly lower than that of the film deposited at a lower temperature. These results suggest that the combination of nucleation layer deposition at lower temperatures and sequential bulk deposition by CVD can significantly reduce film stress.

[Conclusion]
Although the above embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of embodiments of the present invention. Accordingly, the embodiments of the present invention are to be regarded as illustrative and not limiting, and the embodiments are not limited to the details presented herein.

Claims (22)

A method of filling features,
(A) exposing the substrate to alternating pulses 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 over the tungsten nucleation layer;
The chamber pressure in (a) is 10 Torr or less. The method of claim 1, further comprising:
(C) exposing the substrate simultaneously to a reducing agent and a third tungsten-containing precursor to deposit a second bulk tungsten layer. The method of claim 2, further comprising:
(D) includes performing (c) every two or more cycles of (b), wherein one cycle of (b) includes a pulse of hydrogen and a pulse of the second tungsten-containing precursor. Include the method. A method according to any one of claims 1 to 3,
(B) is performed in cycles comprising a pulse of hydrogen and a pulse of said tungsten-containing precursor, each cycle forming a subatomic layer having a thickness of at least about 0.3 mm. A method according to any one of claims 1 to 3,
The method wherein the first tungsten-containing precursor is different from the second tungsten-containing precursor. 6. A method according to claim 5, wherein
The method wherein the first tungsten-containing precursor is fluorine-free. A method according to any one of claims 1 to 3,
The deposited tungsten nucleation layer and the deposited bulk tungsten layer have a tensile stress of less than about 1 GPa per 500Å deposition. A method of depositing tungsten on a substrate, the method comprising:
(A) depositing a tungsten layer on the substrate;
(I) exposing the substrate to a reducing agent; and
(Ii) exposing the substrate to a first fluorine-free tungsten-containing precursor; (a) depositing a tungsten layer on the substrate;
(B) cyclically depositing a bulk tungsten layer, and (b)
(I) exposing the substrate to hydrogen (H ₂ );
(Ii) exposing the substrate to a second tungsten-containing precursor; and
(Iii) repeating (i)-(ii) in one or more cycles to deposit the bulk tungsten layer. The method according to claim 8, comprising:
The method wherein the first fluorine-free tungsten-containing precursor is selected from the group consisting of organometallic tungsten-containing precursors and hexacarbonyl tungsten. 10. A method according to claim 8 or 9, wherein
In (a), the tungsten layer is deposited to a thickness between about 2 and about 100 inches. 10. A method according to claim 8 or 9, wherein
Each cycle in (b) forms a subatomic layer having a thickness of at least about 0.3 mm. A method of filling features,
(A) exposing the substrate to alternating pulses of hydrogen and a first tungsten-containing precursor to deposit a bulk tungsten layer on the substrate;
(B) exposing the substrate simultaneously to a second tungsten-containing precursor and a reducing agent to deposit a second bulk tungsten layer on the substrate. The method of claim 12, comprising:
A method in which (a) and (b) are sequentially repeated. The method of claim 12, comprising:
The tungsten-containing precursor in (b) is a fluorine-free tungsten-containing precursor selected from the group consisting of an organometallic tungsten-containing precursor, tungsten chloride, and hexacarbonyl tungsten. 15. A method according to any one of claims 12 to 14, comprising
The method 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 having a platform configured to hold a substrate;
(B) at least one outlet for connection to a vacuum;
(C) one or more process gas inlets connected to one or more process gas sources;
(D) a controller for controlling operations in the device, the controller comprising:
(I) machine-readable instructions for introducing a reducing agent and a first tungsten-containing precursor into the processing chamber in alternating pulses; and
(Ii) machine-readable instructions for introducing hydrogen and a second tungsten-containing precursor into the processing chamber in alternating pulses;
The chamber pressure in (i) is 10 Torr or less. The apparatus of claim 16, further comprising:
The controller includes (iii) machine-readable instructions for simultaneously introducing a reducing agent and a third tungsten-containing precursor into the processing chamber to deposit a second bulk tungsten layer. The apparatus of claim 16, further comprising:
The controller includes, as (iv), machine readable instructions for performing (iii) every two or more cycles of (ii), wherein one cycle of (ii) includes a pulse of hydrogen and the second A device comprising a pulse of a tungsten-containing precursor. An apparatus according to any of claims 16 to 18, comprising
The first tungsten-containing precursor is different from the second tungsten-containing precursor. An apparatus according to any of claims 16 to 18, comprising
The apparatus wherein the first tungsten-containing precursor is fluorine-free. An apparatus for processing a substrate, the apparatus comprising:
(A) at least one processing chamber having a platform configured to hold a substrate;
(B) at least one outlet for connection to a vacuum;
(C) one or more process gas inlets connected to one or more process gas sources;
(D) a controller for controlling operations in the device, the controller comprising:
(I) machine-readable instructions for introducing hydrogen and a first tungsten-containing precursor into the processing chamber in alternating pulses to deposit a bulk tungsten layer; and
(Ii) an apparatus comprising machine readable instructions for simultaneously introducing a second tungsten-containing precursor and a reducing agent into the processing chamber to deposit a second bulk tungsten layer. The apparatus of claim 21, comprising:
The controller further includes machine readable instructions for sequentially repeating (i) and (ii).

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