Pulsed ALD sequence for low fluorine nucleation layer deposition

Abstract

A method includes providing a 3D structure of a partially fabricated semiconductor substrate to a chamber, the 3D structure including a plurality of sidewalls, a plurality of openings in the sidewalls resulting in a plurality of features having a plurality of interior regions fluidly accessible through the openings; and depositing a tungsten nucleation layer in the plurality of features using one or more deposition cycles, each deposition cycle comprising steps (a)-(c): (a) dosing diborane to the chamber twice or more without sweeping between the dosing of diborane; (b) after step (a), cleaning the chamber; and (c) after step (b), dosing tungsten hexafluoride to the chamber one or more times, where cleaning is performed after each dosing of tungsten hexafluoride.

Description

Incorporated by reference

[0001] The specification of the PCT Application in which this application is being filed is hereby incorporated by reference in its entirety. BACKGROUND

[0002] Deposition of materials including tungsten-containing materials is a component of many semiconductor manufacturing processes. These materials can be used for horizontal interconnects, vias between adjacent metal layers, and contacts between metal layers and devices. As devices shrink and more complex patterning schemes are used in the industry, deposition of tungsten films becomes a challenge. Continued reduction in feature size and film thickness presents various challenges, including high resistivity of thinner films and difficulty in obtaining void-free filled features. Deposition in complex high aspect ratio structures such as 3D NAND structures is particularly challenging.

[0003] The background description provided herein is for the purpose of generally presenting the context of the disclosure. The work of the presently named inventors, to the extent the work is SUMMARY

[0004] Presented herein is a method of forming a tungsten (W) nucleation layer in a feature. The method includes an atomic layer deposition (ALD) pulse sequence using tungsten hexafluoride (WF6) as a reactant, which results in a low fluorine concentration in the deposited W nucleation layer.

[0005] One aspect of the disclosure relates to a method of depositing a tungsten nucleation layer in a 3D structure. The method includes: providing a 3D structure of a partially fabricated semiconductor substrate to a chamber, the 3D structure including a plurality of sidewalls, a plurality of openings in the sidewalls resulting in a plurality of features, the features having a plurality of interior regions fluidly accessible through the openings; depositing a tungsten nucleation layer in the plurality of features using one or more deposition cycles, each deposition cycle including (a)-(c): (a) dosing diborane two or more times to the chamber without a purge between the diborane dosing; (b) purging the chamber after (a); and (c) dosing tungsten hexafluoride one or more times to the chamber after (b), wherein a purge is performed after each tungsten hexafluoride dosing.

[0006] In some embodiments, (c) comprises at least 5, at least 10, or at least 15 tungsten hexafluoride dosing. In some embodiments, the tungsten nucleation layer is deposited on a tungsten nitride film or a tungsten carbonitride film in the plurality of features. In some embodiments, the tungsten nucleation layer is deposited on a titanium nitride film in the plurality of features. In some embodiments, the one or more deposition cycles are used to deposit the tungsten nucleation layer having a thickness of to In some embodiments, (a) consists of 2, 3, or 4 dosing of diborane.

[0007] In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 5 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1020atoms / cm2. 18 3 In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 5 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1020atoms / cm2. 17 3 In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 5 x 1019atoms / cm2. In some embodiments, a fluorine concentration in the tungsten nucleation layer is no more than 1 x 1020atoms / cm2. 17 3

[0008] In some embodiments, a substrate temperature is maintained between 170 °C and 250 °C. In some embodiments, a chamber pressure is between 3 and 10 Torr. In some embodiments, a duration of the at least one diborane dosing in (a) is no more than 1 second. In some embodiments, a duration of the at least one diborane dosing in (a) is less than 1 second. In some embodiments, a duration of the at least one tungsten hexafluoride dosing in (c) is less than 2 seconds.

[0009] Another aspect of the disclosure relates to an apparatus comprising: a processing chamber comprising one or more gas injectors for directing gas in the processing chamber, and one or more substrate supports; a controller configured to execute machine-readable instructions for depositing a tungsten nucleation film using one or more deposition cycles, each deposition cycle comprising (a)-(c): (a) causing diborane to be dosed to the chamber two or more times without a purge between the diborane dosing; (b) causing, after (a), the chamber to be purged; and (c) causing, after (b), tungsten hexafluoride to be dosed to the chamber one or more times, wherein a purge is performed after each tungsten hexafluoride dosing.

[0010] These and other features of the present disclosure will be further illustrated by way of example with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS ​​​​

[0011] Figures 1A-1E Different views and aspects of an exemplary 3D NAND structure are presented.

[0012] Figure 2 Schematic diagrams are presented that feature a nucleation layer.

[0013] Figure 3A And 3B Examples of pulse sequences that can be employed during nucleation layer deposition are presented.

[0014] Figure 4 Schematic examples of methods of filling 3D NAND structures using metals are shown.

[0015] Figures 5-7 Schematic diagrams of apparatus that can be used to perform the methods described herein are shown. DETAILED DESCRIPTION

[0016] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented implementations. The disclosed implementations can be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the disclosed implementations. While the disclosed implementations will be described in conjunction with the specific implementations, it will be understood that they are not intended to limit the disclosed implementations.

[0017] Methods of forming metal nucleation layers in features are provided herein. In particular implementations, these methods are used to fill word line features in 3D NAND structures. However, these methods can also be used to form metal layers in other features including vias and other vertically oriented features. In some implementations, the methods are used for tungsten (W) feature fill.

[0018] The methods described herein are performed on a substrate (which can be housed in a chamber). The substrate can be a silicon or other semiconductor wafer, such as a 200 mm wafer, a 300 mm wafer, or a 450 mm wafer, that includes a wafer having one or more layers of material (e.g., dielectric, conductive, or semiconductive material) deposited thereon.

[0019] The substrate can have features such as vias or contact holes that can be characterized by one or more of a narrow and / or recessed opening, a constriction within the feature, and a high aspect ratio. The features can be formed in one or more of the above-described layers. For example, the features can be formed at least partially in a dielectric layer. In some implementations, 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, at least about 25: 1, or higher. An example of a feature is a hole or via in a semiconductor substrate or layer on a substrate.

[0020] For some metallization schemes, an adhesion layer and / or a barrier layer can be formed prior to filling the metal to line the features. A diffusion barrier is a layer that prevents diffusion of a substance between layers. An adhesion layer is a layer that promotes adhesion of a layer to an underlying layer.

[0021] In some tungsten metallization applications, a tungsten nitride (WN) diffusion barrier can be used. The WN barrier has several advantages over the barrier of the titanium adhesion / nitrided titanium (Ti / TiN) bilayer. These advantages include the ability to conformally deposit thin WN layers, and the ability to deposit WN directly on dielectrics without the need for an adhesion layer. These advantages allow more space to be filled with W, thus reducing the overall contact resistance. In addition, the deposition of WN layers can be performed at much lower temperatures than Ti / TiN, which makes it advantageous for low thermal budget applications.

[0022] In some embodiments, the methods are used to deposit a W nucleation layer on a WN or TiN barrier layer. The methods can be used for word line fill in 3-D NAND structures. Figure 1A A cross-sectional side view of a 3D NAND structure 110 (formed on a silicon or other semiconductor substrate 102) is presented with VNAND stacks (left 125 and right 126), a central vertical structure 130, and a plurality of stack horizontal features 120, with horizontal word line features 120 having a plurality of openings 122 on opposite sidewalls 140 of the central vertical structure 130. Note that, Figure 1A A 3D NAND structure 110 is shown with two stacks that together form a trench-like central vertical structure 130. As Figure 1A shown, there can be more than two stacks arranged in order and spatially parallel to each other, with the gap between each pair of adjacent stacks forming the central vertical structure 130. The horizontal word line features 120 are 3D memory word line features that are fluidly accessible from the central vertical structure 130 through the openings 122. There are Figure 1A The horizontal word line features 120 shown in the 3D NAND stacks 125 and 126 (i.e., left 3D NAND stack 125 and right 3D NAND stack 126) are also accessible from the other sides of these stacks (the leftmost and rightmost sides, respectively) through similar vertical structures formed by additional 3D NAND stacks (on the leftmost and on the rightmost, but not shown). In other words, each 3D NAND stack 125, 126 has stack word line features that are fluidly accessible from both sides of the 3D NAND stack through the central vertical structure 130. In the specific example shown as Figure 1A In the specific example shown as

[0023] Wordline features in a 3D NAND stack can be formed by depositing an alternating stack of silicon oxide and silicon nitride layers, and then selectively removing the nitride layers to leave a stack of oxide layers with gaps between them. These gaps are the wordline features. As long as techniques for forming wordlines are available and techniques for (substantially) vertical feature void- free filling are available, any number of wordlines can be vertically stacked in such a 3D NAND structure. Thus, for example, a 3D NAND stack can include 2 to 512 horizontal wordline features, 2 to 256 horizontal wordline features, 8 to 128 horizontal wordline features, or 16 to 64 horizontal wordline features, etc. (the listed ranges are to be understood as including the recited endpoints).

[0024] Figure 1B Presented Figure 1A is a cross-sectional top view of the same 3D NAND structure 110 shown in the side view of Figure 1A , taken from the horizontal plane of the horizontal dashed line 160. Figure 1B The cross-sectional view of Figure 1B is a top view illustrating that the pillars 155 form a constriction in the openings 122 to the wordline features 120, i.e., the wordline features 120 are inhibited from fluid accessibility from the central vertical structure 130 through the openings 122 (as indicated by the arrow in FIG. 1G) by the pillars 155. This reduction in fluid accessibility increases the difficulty of uniformly filling the wordline features 120 with material. Figure 1C , 1D and 1E further illustrate the structure of the wordline features 120 and the challenge of uniformly filling them with material due to the presence of the pillars 155.

[0025] Figure 1C shows a vertical cut of a similar 3D NAND structure to that shown in Figure 1A , but here focusing on a pair of wordline features 120. Figure 1C Also illustratively shown is a void 175 in a filled wordline feature 120. Figure 1D Also illustratively shown is a void 175, but in this figure via a horizontal cut through the pillars 155, similar to the horizontal cut shown in FIG. 1G. Figure 1E Illustrated is the accumulation of tungsten 133 or other metal around the pillars 155 forming a constriction, which accumulation results in pinching of the opening 122 such that no additional metal can be deposited in the area of the void 175. Figure 1EIt also shows a barrier layer 118 on which a tungsten layer can be deposited, the tungsten layer comprising a nucleation layer and a host layer.

[0026] from Figure 1C and Figure 1D It can be seen that the gapless letter line filling depends on the accumulation of metal deposits around the support 155, causing the opening 122 to clamp and hinder the further migration of the precursor to the letter line feature 120. Sufficient amount of the deposited precursor migrates downwards through the vertical structure 130, through the opening 122, past the constricted support 155, and into the farthest extent of the letter line feature 120. Similarly, Figure 1E The single letter feature 120 is shown as viewed from the top cross section, illustrating how the general conformal deposition of the material begins to clamp the interior of the letter feature 120 due to the significant width of the strut 155 acting as a partial obstruction and / or narrowing and / or restriction of the open path that would otherwise pass through the letter feature 120. (It should be noted that...) Figure 1E The example in can be understood as Figure 1D (A 2D rendering of the 3D features of the constriction section of the support structure, thus illustrating the constriction section as presented in a plan view rather than a cross-sectional view.)

[0027] As 3D NAND structures become more complex, the challenges due to reduced fluid accessibility increase. For example, in some implementations, reactants may diffuse through at least 5, 10, 15, 20, 25, or 30 pillars to reach the innermost word line features. With the increase in the number of pillars, the chance of uneven deposition arises.

[0028] Another challenge in tungsten-line filling is preventing fluorine incorporation into the film and the underlying dielectric. Tungsten hexafluoride (WF6) is a useful precursor because it is a gas under standard conditions, unlike many tungsten halide compounds. However, its use in typical tungsten deposition results in unacceptably high fluorine content. The following describes a method for depositing a tungsten nucleation layer using WF6, which results in a tungsten nucleation layer with good continuity and very low fluorine content. Subsequent processing of tungsten-filled features can also utilize WF6.

[0029] This article describes examples of deposition in features in both the horizontal and vertical directions. It should be noted that, at least in most cases, these examples apply to features in both the horizontal and vertical directions. Furthermore, it should be noted that in the following description, the term "vertical" may be used to refer to a direction generally orthogonal to the plane of the substrate, while the terms "lateral" or "horizontal" may be used to refer to a direction generally parallel to the plane of the substrate.

[0030] Figure 2A schematic example of a word line feature 220 in a 3D NAND structure is depicted. In Figure 2 A 2-D rendering of 3-D features of a partially fabricated 3D NAND structure, including word line features 220 and conformal tungsten nucleation layer 221, is shown in

[0031] For conformal deposition of the tungsten nucleation layer, an atomic layer deposition (ALD) sequence can be used. Such a sequence can employ the following operations: (i) providing a layer of reducing agent on the substrate surface, and (ii) contacting the substrate surface with a tungsten-containing precursor to form a tungsten layer on the substrate. Each of these operations can involve delivering dosed reactants (reducing agent, tungsten-containing precursor) into a chamber housing the substrate including the features. Between these dosings, a purge is performed to purge the reactants from the chamber.

[0032] Diborane (B2H6) can be used as the reducing agent in the methods described herein. B2H6 is an effective reducing agent, however, it is relatively susceptible to thermal decomposition into boron and hydrogen. Due to the complexity of the structure and long diffusion lengths, it can be challenging to deliver diborane throughout the structure with minimal decomposition. Thermal decomposition can result in non-uniformity, with diborane decomposing at the first available surface rather than diffusing through the structure. In the methods described herein, multiple sequential dosings of diborane can be used without intervening purges. A charge volume can be used to deliver the dosings.

[0033] With high volume, multiple dosing of diborane delivery, diborane can diffuse through the entire 3D NAND structure with minimal decomposition. Chamber pressure and substrate temperature can also be controlled to mitigate thermal decomposition. According to various embodiments, the pressure can be between 3 and 10 Torr, and the temperature can be between 170 °C and 250 °C.

[0034] After the delivery of diborane, a purge is performed. This is followed by one or more dosings of a tungsten-containing precursor, with a purge operation after each dosing.

[0035] For the diborane (B2H6) reducing agent and tungsten hexafluoride (WF6) or other tungsten-containing precursor, the sequence can be represented as B x / purge / (W / purge) ywhere B represents B2H6dosing and W represents WF6dosing. This sequence can be repeated for multiple cycles to deposit the W nucleation layer. In the above equation, "x" is an integer of 2 or more, such as 2, 3, or 4, and y is an integer of 1 or more. B x / Purge / (W / Purge) y The sequence itself can be repeated one or more times to deposit the nucleation layer.

[0036] In some embodiments, y (the number of pulses of tungsten-containing precursor in each cycle of the nucleation layer sequence) is at least 2, or at least 3. By using multiple short doses, it is possible to minimize byproduct generation. Subsequent purges remove the generated byproducts before they accumulate. This can allow for complete conversion of adsorbed reducing agent.

[0037] Figure 3A An example of a sequence showing tungsten nucleation deposition. In the example B x / Purge / (W / Purge) y In the sequence, x = 3 and y = 3. Each dose appears as a spike, which represents an increase and decrease in the mass flow of diborane and tungsten hexafluoride into the chamber. This is due to the use of a fill volume. The gases are stored in the fill volume at high pressure (e.g., 400 to 1000 Torr). At the beginning of the dose, the gas is allowed to flow from the fill volume to the chamber, resulting in a rapid decrease in the pressure in the fill volume. The decrease in pressure in the fill volume corresponds to an increase in the mass flow of gas into the chamber. As the pressure in the fill volume decreases, the mass flow of gas into the chamber decreases. In Figure 3A In the example, the purge operation is represented by the capital letter P. However, the purge gas can also be delivered from a fill volume, as described above.

[0038] In Figure 3A , three consecutive diborane doses are shown, followed by a purge. According to various embodiments, the diborane doses can be of the same or different length. For example, multiple 0.5 or 1 second doses can be used. In some embodiments, the number of fill volumes can affect the dose time. For example, if two fill volumes are assigned to a diborane dose, using three doses can involve a longer second dose while the first fill volume is being filled. In one example, a dose sequence of 0.5s / 2.5s / 0.5s (where s is seconds) can be used. Multiple doses of the same duration can be used if the fill volumes are sufficient. The dose duration can be up to 5 seconds, but shorter pulses can help avoid decomposition. In some embodiments, each dose duration is no more than 2 seconds or 1 second. In some embodiments, it can be less than 1 second.

[0039] In Figure 3A , the diborane doses are shown as non-overlapping. However, the diborane doses can overlap, as Figure 3BAs shown, it shows two consecutive, overlapping diborane doses. The number of diborane pulses can be from 2 to 5, such as 2, 3, or 4. In some embodiments, a short single diborane dose can be sufficient.

[0040] According to various embodiments, diborane can be provided with a nitrogen carrier gas (e.g., 5% / 95% B2H6 / N2), and argon can be used to further dilute the diborane, such as 1 : 1 Ar:(B2H6 / N2) or 2: 1 (B2H6 / N2). In some embodiments, diborane can be co-flowed with hydrogen (H2). Hydrogen can be used as a parameter to control the diborane exposure profile. Diborane decomposes slower in the presence of hydrogen than in another carrier gas such as nitrogen (N2). For complex structures that diborane is being processed deep into, hydrogen can be added, for example, in some 3D NAND structures with multiple pillars, hydrogen can be added to allow diborane to pass through one or more pillars without thermal decomposition.

[0041] Returning to Figure 3A After the final diborane dose and after each tungsten hexafluoride dose, a purge is performed. The number of tungsten hexafluoride doses in each sequence can be significantly more than 3, such as 5, 9, 15, 20, 25, etc. In some embodiments, it is at least 3, 5, 9, or 15. The dose time can be less than 5 seconds, less than 2 seconds, or less than 1 second. In some embodiments, it can be 0.25 seconds, 0.5 seconds, or 0.75 seconds, for example. The purge time is also short, such as less than 2 seconds. In some embodiments, it is one second.

[0042] The multiple short time doses of diborane and tungsten hexafluoride improve step coverage and fluorine concentration of the tungsten nucleation layer compared to fewer numbers, longer time doses. This is illustrated in the table below, which shows step coverage and fluorine concentration for various nucleation layer pulse sequences. The top BBW row is an example using a small number, longer sequence with an exemplary pulse time of 5 seconds or more. The middle and last rows use a 0.5s / 2.5s / 0.5s pulse duration for the boron doses, and a 0.25s dose duration for the tungsten hexafluoride doses.

[0043] Resistivity is also significantly improved. For example, for a nucleation layer of about 30 A (body + about 20 A (about 30 A body + about 20 A nucleation layer) film, the resistivity of a nucleation layer deposited using a BW (diborane / purge / tungsten hexafluoride / purge) sequence with a 5 second dose is about 30 μΩ-cm. In contrast, a nucleation layer deposited using a B x / purge / (W / purge) y sequence with significantly shorter doses has a (body + about The resistivity of the film of the nucleation layer) is 26 μΩ-cm.

[0044] Repeatable B x / purge / (W / purge) y sequences to deposit a nucleation layer. Exemplary total nucleation layer thicknesses are in a range from to

[0045] After deposition of the nucleation layer, body deposition can be implemented to deposit a body layer on the nucleation layer. Body deposition can be by ALD or CVD processes. In a CVD process, a reducing agent and a metal precursor are co-flowed into a deposition chamber to deposit a body fill layer in the features. An inert carrier gas can be used to deliver one or more reactant flows, which can be pre-mixed or not. The operation typically includes continuous supply of reactants until the desired amount is deposited. In certain implementations, the CVD operation can be performed in multiple stages, with multiple periods of continuous and simultaneous supply of reactants separated by periods of one or more reactants diverted.

[0046] For conformal deposition and deposition into complex structures such as 3D NAND structures, ALD deposition of the body layer can be used. ALD deposition of the body layer includes exposure to alternating pulses of a metal-containing precursor and a reducing agent separated by an inert purge gas, using the metal precursors described above with reference to nucleation layer deposition. The same or different metal precursors used for nucleation layer deposition can be used for body deposition. Hydrogen is typically the reducing agent used for body deposition, in contrast to nucleation layer deposition using a strong reducing agent such as diborane or silane.

[0047] Deposition can be performed according to various implementations until a particular feature profile is obtained and / or a particular amount of metal is deposited. In some implementations, deposition time and other related parameters can be determined by building a model and / or trial-and-error. In some implementations, the processing chamber can be equipped with various sensors to perform in-situ metrology measurements for endpoint detection of the deposition operation. Examples of in-situ metrology include optical microscopy and X-ray fluorescence (XRF) for confirming the thickness of the deposited film.

[0048] In some embodiments, the conformal tungsten layer can be characterized as low resistivity, and in some embodiments, as low stress and / or low fluorine. Because the word line features are unfilled (except for the nucleation layer), a relatively fast deposition technique can be used. In some embodiments, this includes alternating pulses of a tungsten-containing precursor such as WF6and hydrogen (H2) or other reducing agent to deposit a first tungsten layer in an ALD process. Purge operations can separate the pulses. Relatively short pulse times can be used for deposition to improve throughput. ​

[0049] In some embodiments, the deposition process can involve one or more inhibition operations. Figure 4 A deposition-inhibition-deposition (DID) sequence is shown for a word line in a 3D NAND structure. At 410, a word line feature 402 is shown after conformal deposition of a metal layer 404. The deposition of the metal layer 404 includes deposition of a nucleation layer as described above, and can further include a bulk deposition process. At 420, the feature 402 is shown after an inhibition process. The treated surface 465 extends through the constriction formed by the pillar 451. In this example, the treated surface 465 through the pillar 451 constriction is inhibited, while the surface inside at 452 is not inhibited. Thus, at Figure 4 In the example of FIG. 4, the inhibition process is non-conformal in the lateral direction. However, the process can be uniform in the vertical direction, such that each word line is inhibited at about the same area.

[0050] At 430, a process is performed to selectively deposit metal according to the inhibition profile: bulk metal 408 is preferentially deposited on the non-inhibited portions of the metal layer 404, such that the difficult-to-fill area behind the constriction is filled. At 440, bulk deposition is continued, filling the remaining portions of the feature with bulk metal 408.

[0051] In some embodiments, the nucleation process described above can be used to deposit a nucleation layer of other metals. In such embodiments, a metal-containing precursor is reacted with diborane. Examples of other metal-containing precursors are provided below. Other metal-containing precursors can also be used for the subsequent bulk deposition. For example, a molybdenum-containing precursor can be used for molybdenum word lines, etc. Metal-containing precursor

[0052] As described above, WF6can be used to deposit a W nucleation layer. WF6is a useful precursor because it is in the gas phase under deposition conditions. WF6may also be used for depositing a W bulk layer. In some embodiments, other tungsten-containing precursors can be suitable for carrying out the disclosed embodiments. For example, a metal-organic tungsten-containing precursor can be used. Organic metal precursors and fluorine-free precursors, such as MDNOW (methylcyclopentadienyl-dicarbonyl nitrosyl-tungsten) and EDNOW (ethylcyclopentadienyl-dicarbonyl nitrosyl-tungsten) can also be used. Chlorine-containing tungsten precursors (WCl x ), such as tungsten pentachloride (WCl5) and tungsten hexachloride (WCl6).

[0053] Deposition of other metals can be performed. These include molybdenum, ruthenium, and cobalt. To deposit molybdenum (Mo), molybdenum-containing precursors can be used, including molybdenum hexafluoride (MoF6), molybdenum pentachloride (MoCl5), molybdenum dichloride dioxide (MoO2Cl2), molybdenum oxide tetrachloride (MoOCl4), and molybdenum hexacarbonyl (Mo(CO)6).

[0054] To deposit ruthenium (Ru), Ru-precursors can be used. Examples of ruthenium precursors that can be used in oxidation reactions include (ethylbenzyl)(l-ethyl-l,4- cyclohexadienyl)Ru(0), (l-isopropyl-4-methylbenzyl)(l,3-cyclohexadienyl)Ru(0), 2,3- dimethyl-l,3-butadienyl)Ru(0)tricarbonyl, (l,3-cyclohexadienyl)Ru(0)tricarbonyl, and (cyclopentadienyl)(ethyl)Ru(II)dicarbonyl. Examples of ruthenium precursors that react with non-oxidizing reactants are bis(5-methyl-2,4-hexanediketonato)Ru(II)dicarbonyl and bis(ethylcyclopentadienyl)Ru(II).

[0055] To deposit cobalt (Co), cobalt-containing precursors can be used, including dicarbonylcyclopentadienylcobalt(I), carbonylcobalt, various amidinatocobalt precursors, diazadienylcobalt complexes, amidinatocobalt / guanidinato precursors, and combinations thereof.

[0056] The metal-containing precursors can be reacted with a reducing agent as described above. Diborane can be used as a nucleation layer reducing agent. In some embodiments, H2is used as a reducing agent for main body layer deposition to deposit high purity films.

[0057] As described above, main body deposition can be performed across the wafer. In some implementations, main body deposition can occur by a CVD process, in which a reducing agent and a metal- containing precursor are flowed into a deposition chamber to deposit a main body fill layer in the features. An inert carrier gas can be used to deliver one or more reactant streams, which can or can not be premixed. Unlike a PNL or ALD process, this operation typically includes flowing the reactants continuously until the desired amount is deposited. In certain implementations, the CVD operation can occur in multiple stages, in which multiple time periods of continuous and simultaneous flow of reactants are separated by time periods of flow diversion of one or more reactants. Main body deposition can also be performed using an ALD process, in which the metal-containing precursor is alternated with a reducing agent such as H2. In some implementations, ALD can be used to deposit the initial main body layer in the Dep 1 process, and CVD is used for other feature fill after inhibition. In some implementations, ALD can be used for feature fill, and CVD is used for the cap layer. In some implementations, ALD can be used for all of the main body layer deposition.

[0058] The metal films described herein can include amounts of other compounds, dopants, and / or impurities, such as nitrogen, carbon, oxygen, boron, phosphorus, sulfur, silicon, germanium, etc., depending on the particular precursors and processes used. The metal content of the films can be 20% to 100% (atomic) metal. In many implementations, the films are metal-rich, with at least 50% (atomic) metal, or even at least about 60%, 75%, 90%, or 99% (atomic) metal. In some implementations, the films can be a mixture of a metal or elemental metal (e.g., W, Mo, Co, or Ru) and other metal-containing compounds (e.g., tungsten carbide (WC), tungsten nitride (WN), molybdenum nitride (MoN), etc.). CVD and ALD deposition of these materials can include the use of any suitable precursors as described above.

[0059] For feature fill, a suppression process can be used after deposition of the nucleation layer. A plasma suppression process involves exposure to a plasma generated from a nitrogen-containing compound, such as N2. In some embodiments, the plasma power, chamber pressure, and / or process gas can be pulsed. A thermal suppression process typically involves exposing the feature to a nitrogen-containing compound such as ammonia (NH3) or hydrazine (N2H4) to non-conformally suppress the feature near the feature opening. In some embodiments, the thermal suppression process is performed at a temperature range of 250 °C to 450 °C. At these temperatures, the previously formed tungsten or other layer is exposed to NH3, which produces a suppression effect. Other potential suppression chemistries, such as nitrogen (N2) or hydrogen (H2), can be used to perform thermal suppression at higher temperatures, such as 900 °C. However, for many applications, these high temperatures are outside of the thermal budget. In addition to ammonia, other hydrogen-containing nitrogen agents, such as hydrazine, can be used at lower temperatures suitable for back end of line (BEOL) applications. During thermal suppression, a metal precursor can be flowed with the suppression gas or in alternating pulses with the gas.

[0060] Nitridation of the surface can passivate it. Subsequent deposition of tungsten or other metals, such as molybdenum or cobalt, on the nitrided surface is significantly delayed compared to on a conventional bulk tungsten film. In addition to NF3, a fluorocarbon such as CF4 or C2F8 can also be used. However, in certain implementations, the suppression species does not contain fluorine to prevent etching during suppression.

[0061] In addition to the surfaces described above, nucleation can be suppressed on liner / barrier layer surfaces such as TiN and / or WN surfaces. Any chemistry that passivates these surfaces can be used. The suppression chemistry can also be used to adjust the suppression profile, where different ratios of active suppression species are used. For example, for suppression of a W surface, nitrogen can have a stronger suppression effect than hydrogen; adjustment of the ratio of N2 and H2 gases in the forming gas can be used to adjust the profile.

[0062] In some implementations, the substrate can be heated or cooled prior to the inhibition. The predetermined temperature of the substrate can be selected to induce a chemical reaction between the feature surface and the inhibiting species and / or to promote adsorption of the inhibiting species, as well as to control the rate of the reaction or adsorption. For example, the temperature can be selected to have a high reaction rate, so that more inhibition occurs near the gas source. Apparatus

[0063] Any suitable chamber can be used to practice the disclosed embodiments. Exemplary deposition apparatuses include a variety of systems, such as and Max, available from Lam Research Corp. (Fremont, California), or any of a variety of other commercially available processing systems.

[0064] In some embodiments, the first deposition can be performed at a first station, which is one of two, five, or more deposition stations located within a single deposition chamber. Thus, for example, diborane and tungsten hexafluoride can be introduced at the first station, as described above, to deposit a nucleation layer to the surface of a semiconductor substrate, which uses independent gas supply systems to create a localized ambient atmosphere at the substrate surface. The same or another station can use ALD to deposit a conformal layer. A third station can be used for an inhibition process, followed by another bulk deposition operation.

[0065] Figure 5 A schematic of a processing system suitable for performing deposition processes according to embodiments is shown. System 500 includes a transfer module 503. Transfer module 503 provides a clean, pressurized environment to minimize the risk of contamination of the substrates being processed as they are moved between various reactor modules. A multi-station reactor 509 mounted on transfer module 503 is capable of ALD deposition of a W nucleation layer and / or other metal films, inhibition operations, and CVD according to various embodiments. Multi-station reactor 509 can include multiple stations 511, 513, 515, and 517, which can be operated sequentially according to the disclosed embodiments. For example, multi-station reactor 509 can be configured so that station 511 performs W nucleation layer deposition using WF6and B2H6, station 513 performs bulk deposition of a conformal film of ALD tungsten using H2as a reducing agent, station 515 performs nitridation using NH3, and station 517 can perform bulk ALD fill following a process using H2as a reducing agent. In another example, station 511 can perform deposition of a WN layer, station 513 performs ALD deposition of a conformal layer including a nucleation layer, station 515 performs a NF3treatment operation, and station 517 can perform bulk ALD fill following a process using H2as a reducing agent. The stations can include a heated pedestal or substrate support, one or more gas inlets or showerheads or disperser plates.

[0066] Returning to Figure 5One or more single or multi-station modules 507 capable of plasma or chemical (non-plasma) pre-clean, other deposition operations or etch operations can also be mounted on the transfer module 503. Modules can also be used for various processes, e.g., to prepare the substrate for a deposition process. The system 500 also includes one or more wafer source modules 501 in which wafers are stored prior to processing and after processing. Atmospheric robots (not shown) in the atmospheric transfer chamber 519 can first move the wafers from the source module 501 to the load lock 521. Wafer handling equipment (typically robot arms) in the transfer module 503 move the wafers from the load lock 521 to the modules mounted on the transfer module 503 and between modules.

[0067] In various embodiments, a system controller 529 is employed to control the process conditions during deposition. The controller 529 will typically include one or more memory devices and one or more processors. The processors can include CPUs or computers, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0068] The controller 529 can control the activities of all of the deposition devices. The system controller 529 runs system control software that includes sets of instructions for controlling timing, gas mixtures, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or susceptor position, and other parameters of a particular process. In some embodiments, other computer programs stored on memory devices associated with the controller 529 can be used.

[0069] Typically, there will be a user interface associated with the controller 529. The user interface can include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0070] The system control logic can be configured in any suitable manner. Generally, the logic can be designed or configured in hardware and / or software. The instructions for controlling the drive circuitry can be hard coded or provided as software. The instructions can be provided by "programming." Such programming is understood to include any form of logic, including hard coded logic in digital signal processors, application specific integrated circuits, and other devices having specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that can be executed on a general purpose processor. The system control software can be coded in any suitable computer readable programming language.

[0071] Computer program code for controlling the pulses of germanium-containing reducing agent, hydrogen flow, and pulses of tungsten-containing precursor, and other processes in a process sequence can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program. As indicated, the program code can be hard coded.

[0072] Controller parameters relate to process conditions such as, for example, process gas composition and flow rate, temperature, pressure, cool down gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of a recipe and can be entered using a user interface.

[0073] Signals for monitoring the process can be provided through analog and / or digital input connections of the system controller 529. Signals for controlling the process are output through analog and digital output connections of the deposition apparatus 500.

[0074] The system software can be designed or configured in a number of different ways. For example, a plurality of chamber component subroutines or control routines can be written to control operation of the chamber components needed to perform a deposition process according to the disclosed embodiments. Examples of program or segments of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0075] In some implementations, the controller 529 is part of a system, which can be part of the above-described examples. Such systems can include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronics for controlling the operation of the systems prior to, during, and after processing of a semiconductor wafer or substrate. The electronics can be referred to as the “controller,” which can control various components of a system or systems. The controller 529, depending on the processing requirements and / or system type, can be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfer into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a particular system.

[0076] Broadly speaking, the controller can be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits can include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions can be instructions (or sets of instructions) that are executed by the controller to implement one or more processes, algorithms, or other instructions (or sets of instructions) that are executable by the controller. The software can be stored in the memory. The memory can be embedded in the controller. The memory can be external to the controller and connected to the one or more microprocessors or microcontrollers via a memory port or a built-in storage interface. The memory can be connected to the one or more microprocessors or microcontrollers by a storage interface (e.g., shared storage, etc.). The controller, in some implementations, can be a part of, or coupled to, a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller can be in "the cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer can enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, change parameters of current processing, set processing steps to follow in the current process, or start new processes. In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which can include a local network or the Internet. The remote computer can include a user interface that enables entry or programming of parameters and / or settings, which are then transmitted over the network to the system. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. The parameters can be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller can be distributed across all or a portion of the system. For example, one or more of the components of the controller, such as the memory, one or more of the processors, or the like, can be remote to the system, such as on a server in a data center. Examples of

[0077] In some implementations, the controller 529 can be part of, or coupled to, a computer that is integrated within, coupled to, otherwise networked to, or a combination thereof, the system. For example, the controller 529 can be in "the cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer can enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, change parameters of current processing, set processing steps to follow in the current process, or start new processes. In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which can include a local network or the Internet. The remote computer can include a user interface that enables entry or programming of parameters and / or settings, which are then transmitted over the network to the system. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. The parameters can be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller can be distributed across all or a portion of the system. For example, one or more of the components of the controller, such as the memory, one or more of the processors, or the like, can be remote to the system, such as on a server in a data center. Examples of

[0078] An exemplary system can include, but is not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a CVD chamber or module, an ALD chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that can be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0079] As described above, depending on the process step or steps to be performed by the tool, the controller can communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0080] The controller 529 can include different programs. A substrate positioning program can include program code for controlling the chamber components used to load a substrate onto a susceptor or chuck and control the spacing between the substrate and other components of the chamber, such as the gas inlets and / or the target. A process gas control program can include code for controlling the gas composition, flow rate, pulse time, and optionally for flowing gas into the chamber prior to deposition in order to stabilize the pressure in the chamber. A pressure control program can include code for controlling the pressure in the chamber by adjusting a throttle valve in an exhaust system, for example. A heater control program can include code for controlling the current to heating units used to heat the substrate. Alternatively, the heater control program can control the delivery of a heat transfer gas, such as helium, to the wafer chuck.

[0081] Examples of chamber sensors that can be monitored during deposition include mass flow controllers, pressure sensors such as a manometer, and thermocouples located in the susceptor or chuck. Appropriately programmed feedback and control algorithms can be used with data from these sensors to maintain the desired process conditions.

[0082] Figure 6 A schematic of an embodiment of a processing station 600 having a processing chamber 602 for maintaining a low pressure environment is depicted. In some embodiments, multiple processing stations can be contained in a common low pressure processing tool environment. For example, Figure 5 Embodiments of a multi-station reactor 509 are described. In some embodiments, one or more hardware parameters of the processing station 600, including those discussed in detail below, can be adjusted in a programmed manner by one or more computer controllers 650. In other embodiments, the processing chamber can be a single-station chamber.

[0083] The processing station 600 is in fluid communication with a reactant delivery system 601a to deliver process gases to the distribution showerhead 606. The reactant delivery system 601a includes a mixing vessel 604 for mixing and / or conditioning process gases, such as a metal-containing precursor gas, a hydrogen-containing gas, an inert gas, argon or other carrier gas, or other reactant-containing gas, for delivery to the showerhead 606. One or more fill volumes 620 can control the introduction of process gases into the mixing vessel 604.

[0084] As an example, Figure 6 Embodiments include a vaporization point 603 for vaporizing liquid reactants to be supplied to the mixing vessel 604. In some embodiments, the vaporization point 603 can be a heated vaporizer. In some embodiments, the liquid precursor or liquid reactant can be vaporized at a liquid injector (not shown). For example, the liquid injector can inject pulses of liquid reactant into a carrier gas stream upstream of the mixing vessel 604. In an embodiment, the liquid injector can vaporize the reactant by flashing the liquid from a higher pressure to a lower pressure. In another example, the liquid injector can atomize the liquid into dispersed droplets that are subsequently vaporized in a heated delivery tube. Smaller droplets can vaporize faster than larger droplets, thereby reducing the delay between liquid injection and completion of vaporization. Faster vaporization can reduce the length of piping downstream of the vaporization point 603. In one aspect, the liquid injector can be mounted directly to the mixing vessel 604. In another aspect, the liquid injector can be mounted directly to the showerhead 606.

[0085] In some embodiments, a liquid flow controller (LFC) can be provided upstream of the vaporization point 603 to control the mass flow of liquid for vaporization and delivery to the processing chamber 602. For example, the LFC can include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC can then be adjusted in response to a feedback control signal provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it can take one or more seconds to stabilize the liquid flow using feedback control. This can extend the time to dose the liquid reactant. Accordingly, in some embodiments, the LFC can dynamically switch between a feedback control mode and a direct control mode. In some embodiments, this can be performed by disabling the sensing piping of the LFC and the PID controller. According to various embodiments, one or more fill volumes can be connected to the process gas supply.

[0086] In some embodiments, solid precursors can be supplied in an ampoule cartridge 613, which can deliver the precursors from the ampoule cartridge 613 to the processing chamber 602.

[0087] In some embodiments, the station can be equipped with one or more fill volumes. Pulse-wise providing of reactants, purge, and / or inert gases can involve the fill volumes. An exemplary apparatus is shown inFigure 7 In this configuration, each of four gas sources (precursor, B2H6, H2, and purge gas) is connected to a filling volume 701. According to various embodiments, all or only a subset of these gas sources may be connected to the filling volume 701. The filling volume 701 is used to establish a pressurized volume for the gases, which then flow into the processing chamber. The gases from the filling volume 701 are pressurized (e.g., to 300–700 Torr) and enter the chamber via a nozzle 706. A base 708 for supporting the wafer is also shown.

[0088] Back Figure 6 The nozzle 606 dispenses process gas toward the substrate 612. Figure 6 In the illustrated embodiment, the substrate 612 is located below the nozzle 606 and is shown mounted on a base 608. The nozzle 606 may have any suitable shape and may have any suitable number and arrangement of ports to distribute process gases to the substrate 612.

[0089] In some embodiments, the base 608 can be raised or lowered to expose the substrate 612 to the volume between the substrate 612 and the nozzle 606. In some embodiments, the base 608 can be temperature-controlled by a heater 610. The base 608 can be set to any suitable temperature during operation for performing the various disclosed embodiments. It should be understood that in some embodiments, the base height can be adjusted programmatically via a suitable computer controller 650. At the end of a process stage, the base 608 can be lowered during another substrate transfer stage to allow removal of the substrate 612 from the base 608.

[0090] In some embodiments, the position of the nozzle 606 can be adjusted relative to the base 608 to change the volume between the substrate 612 and the nozzle 606. Furthermore, it should be understood that the vertical position of the base 608 and / or the nozzle 606 can be changed by any suitable mechanism within the scope of this disclosure. In some embodiments, the base 608 may include a rotation axis for rotating the orientation of the substrate 612. In some embodiments, one or more of these exemplary adjustments can be performed programmatically by one or more suitable computer controllers 650. The computer controller 650 may include the following regarding... Figure 6 The controller 650 describes any of the features.

[0091] If plasma is used during deposition or inhibition, the showerhead 606 and the pedestal 608 are electrically connected to a radio frequency (RF) power source 614 and a matching network 616 to power the plasma. In some embodiments, the energy of the plasma can be controlled by controlling one or more of the process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 614 and the matching network 616 can operate at any suitable power to form a plasma having a desired composition of radical species. Similarly, the RF power source 614 can provide RF power at any suitable frequency. In some embodiments, the RF power source 614 can be configured to control a high frequency RF power source and a low frequency RF power source independently of one another. Exemplary low frequency RF frequencies can include, but are not limited to, frequencies between 0 kHz and 900 kHz. Exemplary high frequency RF frequencies can include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz, or frequencies greater than about 13.56 MHz, or greater than 27 MHz, or greater than 80 MHz, or greater than 60 MHz. It will be appreciated that any suitable parameters can be adjusted discretely or continuously to provide plasma energy for surface reactions.

[0092] In some embodiments, the plasma can be monitored in situ by one or more plasma monitors. In one case, the plasma power can be monitored by one or more voltage, current sensors (e.g., VI probes). In another case, the plasma density and / or process gas concentration can be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters can be adjusted programmatically based on measurements from such in situ plasma monitors. For example, an OES sensor can be used in a feedback loop to provide programmed control of the plasma power. It will be appreciated that in some embodiments, other monitors can be used to monitor the plasma and other process characteristics. Such monitors can include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure sensors.

[0093] In some implementations, instructions for the controller 650 can be provided via input / output control (IOC) sequencing instructions. In one example, instructions for setting conditions for a process stage can be included in the corresponding formulation stage of the process formulation. In some cases, process formulation stages can be arranged sequentially such that all instructions for a process stage are executed concurrently with that process stage. In some implementations, instructions for setting one or more reactor parameters can be included in the formulation stage. For example, a first formulation stage may include instructions for setting the flow rate of an inert gas and / or reactant gas (e.g., a metal precursor), instructions for setting the flow rate of a carrier gas (e.g., argon), and a time delay instruction for the first formulation stage. A subsequent second formulation stage may include instructions for adjusting or stopping the flow rate of the inert gas and / or reactant gas, instructions for adjusting the flow rate of the carrier gas or purge gas, and a time delay instruction for the second formulation stage. A third formulation stage may include instructions for adjusting the flow rate of H2, instructions for adjusting the flow rate of the carrier gas or purge gas, and a time delay instruction for the third formulation stage. The subsequent fourth formulation stage may include instructions for adjusting or stopping the flow rates of the inert gas and / or reactant gas, instructions for adjusting the flow rates of the carrier gas or purge gas, and instructions for a time delay for the fourth formulation stage. It should be understood that, within the scope of this disclosure, these formulation stages may be further subdivided and / or repeated in any suitable manner.

[0094] Furthermore, in some implementations, pressure control for the treatment station 600 can be provided by a butterfly valve 618. For example... Figure 6 As shown in the embodiment, butterfly valve 618 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of processing station 600 can also be adjusted by changing the flow rate of one or more gases introduced into processing station 600.

[0095] The foregoing describes embodiments of the application implemented in single- or multi-chamber semiconductor processing tools. The apparatuses and processes described herein can be used in conjunction with photolithographic patterning tools or processes, e.g., for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, though not necessarily, these tools / processes will be used or operated together in a common manufacturing facility. Photolithographic patterning of a film typically includes some or all of the following steps, each of which enables multiple viable tools: (1) coating a photoresist on a workpiece, i.e., a substrate, using a spin-on or spray-on tool; (2) curing the photoresist using a hot plate or a heating furnace or a UV curing tool; (3) exposing the photoresist to visible or UV or X-rays using a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern to an underlying film or workpiece by using a dry or plasma- assisted etching tool; and (6) removing the resist using a tool such as a radio frequency or microwave plasma resist stripper.

[0096] Unless otherwise stated, ranges include endpoints. For example, between 170 °C and 250 °C.

[0097] The foregoing describes embodiments of the application implemented in single- or multi-chamber semiconductor processing tools. The apparatuses and processes described herein can be used in conjunction with photolithographic patterning tools or processes, e.g., for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, though not necessarily, these tools / processes will be used or operated together in a common manufacturing facility. Photolithographic patterning of a film typically includes some or all of the following steps, each of which enables multiple viable tools: (1) coating a photoresist on a workpiece, i.e., a substrate, using a spin-on or spray-on tool; (2) curing the photoresist using a hot plate or a heating furnace or a UV curing tool; (3) exposing the photoresist to visible or UV or X-rays using a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern to an underlying film or workpiece by using a dry or plasma- assisted etching tool; and (6) removing the resist using a tool such as a radio frequency or microwave plasma resist stripper. CONCLUSION

[0098] While the forgoing implementations have been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications can be made within the scope of the appended claims. It should be noted that there are many alternative ways of implementing both the processes, systems, and apparatuses presented. Accordingly, the present implementations are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein.

Claims

1. A method comprising: providing a 3D structure of a partially fabricated semiconductor substrate to a chamber, the 3D structure comprising a plurality of sidewalls, a plurality of openings in the sidewalls resulting in a plurality of features, the features having a plurality of interior regions fluidly accessible through the openings; depositing a tungsten nucleation layer in the plurality of features using one or more deposition cycles, each deposition cycle comprising (a)-(c): (a) dosing diborane to the chamber two or more times without a purge between the diborane dosing; (b) purging the chamber after (a); and (c) dosing tungsten hexafluoride to the chamber one or more times after (b), wherein a purge is performed after each tungsten hexafluoride dosing.

2. The method of claim 1, wherein (c) comprises at least 5 tungsten hexafluoride dosings.

3. The method of claim 1, wherein (c) comprises at least 10 tungsten hexafluoride dosings.

4. The method of claim 1, wherein (c) comprises at least 15 tungsten hexafluoride dosings.

5. The method of claim 1, wherein the tungsten nucleation layer is deposited on a tungsten nitride film or a tungsten carbonitride film in the plurality of features.

6. The method of claim 1, wherein the tungsten nucleation layer is deposited on a titanium nitride film in the plurality of features.

7. The method of claim 1, wherein the one or more deposition cycles are used to deposit the tungsten nucleation layer having a thickness of to thousand angstroms.

8. The method of claim 1, wherein (a) consists of 2, 3, or 4 dosings of diborane.

9. The method of claim 1, wherein a concentration of fluorine in the tungsten nucleation layer is no more than 1 x 1019 atoms / cm2. 18 atoms / cm2 3 .

10. The method of claim 1, wherein a concentration of fluorine in the tungsten nucleation layer is no more than 5 x 1019 atoms / cm2. 17 atoms / cm2 3 .

11. The method of claim 1, wherein a concentration of fluorine in the tungsten nucleation layer is no more than 1 x 1019 atoms / cm2. 17 atoms / cm2 3 .

12. The method of claim 1, wherein a substrate temperature is maintained between 170 °C and 250 °C.

13. The method of claim 1, wherein a chamber pressure is between 3 and 10 Torr.

14. The method of claim 1, wherein a dosing duration of at least one diborane dosing in (a) is no more than 1 second.

15. The method of claim 1, wherein a dosing duration of at least one diborane dosing in (a) is less than 1 second.

16. The method of claim 1, wherein a dosing duration of at least one tungsten hexafluoride dosing in (c) is less than 2 seconds.

17. An apparatus comprising: a process chamber comprising one or more gas injectors for directing gas in the process chamber, and one or more substrate supports; a controller configured to execute machine-readable instructions for depositing a tungsten nucleation film using one or more deposition cycles, each deposition cycle comprising (a)-(c): (a) causing diborane to be dosed to the chamber two or more times without a purge between the diborane dosing; (b) causing the chamber to be purged after (a); and (c) causing tungsten hexafluoride to be dosed to the chamber one or more times after (b), wherein a purge is performed after each tungsten hexafluoride dosing.

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