Methods of etching or depositing

Abstract

A method for (a) etching a film of Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, or TiN, or (b) depositing tungsten on a surface of a film selected from the group consisting of Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, Ir, SiN, TiN, TaN, WN, and SiO2, or (c) selectively depositing tungsten on a metal substrate (e.g., W, Mo, Co, Ru, Ir, and Cu) and not on a metal nitride or dielectric oxide film, the method comprising exposing the film to WOCl4 in the presence of a reducing gas under process conditions.

Description

Technical Field

[0001] This disclosure generally relates to etching certain materials (including alumina, zirconium oxide, hafnium oxide, and combinations thereof, and titanium nitride, tantalum nitride, and tungsten nitride) and depositing tungsten on certain materials (including tungsten, molybdenum, cobalt, ruthenium, aluminum, alumina, titanium nitride, tantalum nitride, tungsten nitride, and silicon dioxide films present on microelectronic devices) using WOCl4. Background Technology

[0002] Etching of alumina (Al₂O₃) surfaces, which act as capacitor films, has shown great interest in many microelectronic devices, particularly those utilizing atomic layer etching. Current methods are generally complex and expensive, requiring multiple steps. Furthermore, the nucleation of the metal and the uniform deposition of the metal on the surface of the alumina film have proven difficult, and even when successful, the adhesion between the two materials remains unsatisfactory. Moreover, existing methods generally cannot provide conformal coverage of tungsten on the alumina surface. For applications such as contacts, interconnects, nucleation layers, seed layers, and hard shielding, tungsten metal may need to be deposited onto various substrates. For all these potential applications, a high-purity metal with uniformity within the deposited film is ideal for achieving the highest performance levels of the deposited film. Summary of the Invention

[0003] Generally, this disclosure provides a method for (a) etching a film of Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, or TiN, or (b) depositing tungsten on the surface of a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, Ir, SiN, TiN, TaN, WN, and SiO2, said method comprising exposing the film to WOCl4 in the presence of a reducing gas under heterogeneous process conditions, wherein the film is etched or tungsten is deposited on the surface of the film. Deviations between the primary etching process and the primary deposition process can be controlled by: 1) changing the substrate temperature (i.e., (T... sub )); 2) Directly change the vapor phase concentration of the WOCl4 precursor by manipulating the precursor vapor pressure, deposition (or etching) pressure or concentration; and / or 3) Change the type of substrate that is being exposed to WOCl4 vapor.

[0004] Therefore, in one aspect, this disclosure provides a method comprising:

[0005] The substrate was exposed to WOCl4 and reducing gas in the reaction zone under the following conditions:

[0006] (a) A substrate is controllably etched under a first set of heterogeneous process conditions, wherein the substrate comprises a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, and SiN films; or

[0007] (b) Tungsten is controllably deposited on the surface of a substrate under the second set of heterogeneous process conditions, wherein the substrate comprises a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN and SiO2 films.

[0008] On the other hand, this disclosure provides a method comprising:

[0009] In a reaction zone, a substrate containing a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, and SiN films is exposed to (i) WOCl4 along with a carrier gas supplied from a precursor ampoule and (ii) a reducing gas, wherein the pressure in the reaction zone is about 0.5 to 500 Torr; the substrate temperature is about 200°C to 1000°C; the reducing gas flow rate is about 0.1 to 10 liters per minute; the carrier gas flow rate is about 0.001 to 1 liter per minute; the concentration of WOCl4 in the reaction zone is greater than 1000 ppm; and the precursor ampoule temperature is about 10°C to about 180°C, thereby etching the substrate containing a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, and SiN films.

[0010] On the other hand, this disclosure provides a method comprising:

[0011] In a reaction zone, a substrate containing a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN, and SiO2 films is exposed to (i) WOCl4 along with a carrier gas supplied from a precursor ampoule and (ii) a reducing gas, wherein the pressure in the reaction zone is about 0.5 Torr to 500 Torr; the substrate temperature is about 200°C to 1000°C; the reducing gas flow rate is about 0.1 to 10 L / min; the carrier gas flow rate is about 0.001 to 1 L / min; the concentration of WOCl4 is less than 1000 ppm; and the precursor ampoule temperature is about 10°C to about 180°C, thereby depositing tungsten on the surface of the substrate containing a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN, and SiO2 films.

[0012] In another aspect, this disclosure provides a method comprising:

[0013] In the reaction zone, a substrate containing a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, Cu, Ir, SiN, TiN, and SiO2 films is exposed to (i) WOCl4 along with a carrier gas supplied from the precursor ampoule and (ii) a co-reactant reducing gas, wherein the pressure in the reaction zone is about 0.5 Torr to 500 Torr; the substrate temperature is about 200°C to 1000°C; the reducing gas flow rate is about 0.1 to 10 L / min; the carrier gas flow rate is about 0.001 to 1 L / min; the concentration of WOCl4 is less than 1000 ppm; and the precursor ampoule temperature is between about 10°C and about 180°C, thereby selectively depositing tungsten onto a metal conductor film (e.g., W, Mo, Co, Ru, Cu, Ir) and other suitable metal conductor films, rather than onto nitride and / or dielectric oxide films. Attached Figure Description

[0014] This disclosure will be more thoroughly understood by considering the following description of various illustrative embodiments in conjunction with the accompanying drawings.

[0015] Figure 1 The etching rate of Al2O3 in chemical vapor etching (CVE) process A graph showing the relationship between substrate temperature (°C).

[0016] Figure 2 This is a graph showing the etching rates of TiN at temperatures of 430, 475, and 520 °C. The TiN etching rates were plotted during a pulsed chemical vapor etching (PVE) process. A graph with cyclic numbers.

[0017] Figure 3 This is a graph showing tungsten deposition on TiN at temperatures of 430, 475, and 520 °C using WOCl4 as a precursor. This data was generated under pulsed chemical vapor deposition conditions of 80 Torr pressure, 100 sccm argon carrier gas, and 2000 sccm H2 flow rate. The graph is plotted using… A graph showing tungsten deposition versus cycle number in units of tungsten.

[0018] Figure 4 This paper describes the use of WOCl4 as a precursor for pulsed chemical vapor deposition (pulse CVD) of tungsten onto titanium nitride. The plot is shown below. A graph showing tungsten deposition in units of seconds and pulse "working time" for the precursor.

[0019] Figure 5 This paper elucidates the effect of pulse "off time" on titanium nitride substrate exposure to pulsed CVD conditions using WOCl4 as a precursor. Other conditions included a pressure of 80 Torr, an argon carrier gas flow rate of 100 sccm, and a continuous H2 flow rate of 1000 sccm. A graph of titanium nitride etching rate versus pulse "off time" is plotted.

[0020] Figure 6 This is a simplified drawing of an atomic layer deposition (ALD) process for practicing the methods of this disclosure.

[0021] Figure 7 This is a simplified drawing of a chemical vapor deposition (CVD) process for practicing the methods of this disclosure.

[0022] Figure 8 This is a simplified drawing of the "pulse CVD" process for practicing the methods of this disclosure.

[0023] Figure 9 This is a simplified drawing of the reaction chamber suitable for carrying out the methods of this disclosure.

[0024] While various modifications and alternatives may be made to this disclosure, its details have been shown in the drawings by way of example and will be described in detail. However, it should be understood that this disclosure does not limit its aspects to the specific illustrative embodiments described herein. Rather, it is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. Detailed Implementation

[0025] As used in this specification and the appended claims, unless otherwise expressly specified herein, the singular forms “a,” “an,” and “the” include the plural references. As used in this specification and the appended claims, unless otherwise expressly specified herein, the term “or” is generally used in its meaning, including “and / or.”

[0026] The term "approximately" generally refers to a range of values ​​that are considered equivalent to the enumerated values ​​(e.g., having the same function or result). In many cases, the term "approximately" may include a value rounded to the nearest significant figure.

[0027] The range of values ​​represented by endpoints includes all values ​​within the range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0028] As indicated above, in a first aspect, this disclosure provides a method comprising:

[0029] The substrate was exposed to WOCl4 and reducing gas in the reaction zone under the following conditions:

[0030] (a) Under the first set of process conditions, a substrate film containing Al2O3 or TiN can be controllably etched; or

[0031] (b) Tungsten is controllably deposited on the surface of a substrate under the second set of process conditions, wherein the substrate is selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN and SiO2 films.

[0032] Generally, the process conditions referenced above are those shared by chemical vapor deposition (CVD) and atomic layer deposition (ALD). In this regard, the pressure is typically from about 1 Torr to about 80 Torr, and the temperature is from about 350°C to about 750°C. The WOCl4 precursor material, along with the desired substrate and an inert carrier gas (e.g., argon, helium, or nitrogen) and a co-reactant reducing gas (e.g., hydrogen), are fed into the reaction chamber. The co-reactant reducing gas is introduced into the system to react with the precursor material to produce intermediate compounds and / or reaction byproducts. The film can be deposited or etched using CVD, pulsed CVD, and / or ALD reaction processes.

[0033] The reducing gas for the co-reactants can be selected from those known in CVD / ALD technology, including H2, NH3, hydrazine, and alkyl hydrazine (e.g., N2H4, CH3HNNH2, CH3HNNHCH3).

[0034] In some embodiments, the method is carried out in a single phase, and the substrate is processed under controlled conditions for a selected period of time to etch a selected film or deposit tungsten onto the selected film. In some embodiments and process conditions, etching occurs first, followed by deposition.

[0035] In other embodiments, the reaction can be carried out in a pulsed process. In this process, the sequential processing steps are generally referred to as “pulsing” or cycling. These processes are based on controlled, self-limiting surface reactions of precursor chemicals. Gas-phase reactions are avoided by alternating and sequentially contacting the substrate with one or more precursors. Process reactants are separated from each other on the substrate surface in a timely manner, for example, by removing excess reactants and / or reactant byproducts from the reaction chamber between reactant pulses. In some embodiments, the precursors are pulsed into the chamber while co-reactant reducing gases are continuously flowed into the reactor. This embodiment will be referred to as a “pulsed CVD” mode. In some embodiments, one or more substrate surfaces are alternately and sequentially contacted with two or more process precursors or reactants. Contacting the substrate surface with gas-phase reactants means that the reactant vapors are in contact with the substrate surface for a limited or controlled period of time. In other words, it is understood that the substrate surface is exposed to the process precursors for a limited period of time.

[0036] Reactors suitable for growing thin films can be used for the deposition described herein. These reactors include ALD reactors and CVD reactors equipped with suitable devices and components for providing precursors (e.g., WOCl4) and co-reactants (i.e., reducing gases) in a “pulsed” manner. According to some embodiments, nozzles in the reactor can also be used to provide uniform delivery of the WOCl4 precursor to the wafer. Examples of suitable reactors that can be used include commercially available equipment and homemade reactors, and will be known to those skilled in the art of CVD, pulsed CVD, and / or ALD. Illustrative reactors are shown in Figure 9 middle.

[0037] In short, the substrate containing the desired film listed above is typically heated to a suitable deposition or etching temperature in the range of 200°C to 1000°C under a pressure of approximately 0.5 to 500 Torr. In other embodiments, the temperature is approximately 350°C to 700°C or 400°C to 600°C. The deposition or etching temperature is generally maintained below the thermal decomposition temperature of the WOCl4 precursor and high enough to prevent reactant agglomeration and provide sufficient energy to initiate the desired surface reaction. The surface of the substrate is in contact with the WOCl4 precursor. In some embodiments, a pulse of the WOCl4 precursor is supplied to the reaction space containing the substrate. In other embodiments, the substrate is moved to the reaction space containing the WOCl4 precursor. Process conditions are generally selected such that no more than about one monolayer of the WOCl4 precursor is adsorbed onto the substrate surface in a self-limiting manner. The appropriate contact time can be readily determined by a skilled technician based on the specific process conditions, substrate, and reactor configuration. Excess WOCl4 precursor and reaction byproducts (if any) are removed from the substrate surface, for example by purging with an inert gas, purging with a reducing gas, or by removing the substrate in the presence of the first reactant.

[0038] Purging means removing process precursors and / or process byproducts from the substrate surface and the process chamber, for example by evacuating the chamber using a vacuum pump and / or by purging the gas inside the reactor with an inert gas (e.g., argon, helium, or nitrogen), and / or by purging the gas inside the reactor with a reducing gas (e.g., hydrogen). In some embodiments, the purging time is about 0.05 to 120 seconds, between about 0.05 and 10 seconds, or between about 0.05 and 2 seconds. However, other purging times may be used as needed, for example, in cases involving highly conformal stepped coverage on structures with extremely high aspect ratios or other complex surface morphologies.

[0039] In some embodiments, each stage of each cycle is generally self-limiting. An excess of reactant precursor is supplied in each stage to saturate the sensitive structural surface. Surface saturation ensures that the reactant occupies all available reactive sites (e.g., targets constrained by physical size or "steric hindrance"), and thus ensures excellent step coverage. Typically, less than one molecular layer of material is deposited per cycle; however, in some embodiments, more than one molecular layer is deposited during each cycle.

[0040] Removing excess reactants may include purging some of the contents of the reaction chamber and / or purging the reaction chamber with helium, nitrogen, argon, or another inert gas. In some embodiments, purging may be performed with a reducing gas. In some embodiments, purging may include shutting off the reactive gas flow while continuing to allow inert carrier gas or reducing gas to flow into the reaction chamber. In another embodiment, the purging step may employ a vacuum step to remove excess reactants from the surface. In some embodiments, the WOCl4 precursor is pulsed into the reaction chamber containing the substrate / film for a period of about 0.05 to about 20 seconds, and then, although not pulsed, the carrier gas and co-reactant reducing gas continue to flow into the reactor, thus serving to purge excess precursors from the reaction chamber. In a separate embodiment, the precursor is pulsed into the reaction chamber and then purged, a reducing gas is pulsed into the reactor and then purged, and this cycle is repeated to achieve a deposited tungsten film of the desired thickness or to remove it by etching an exposed film of the desired thickness.

[0041] In the methods disclosed herein, the precursor WOCl4 is preferred for thin-film tungsten deposition under the following conditions:

[0042] • Pressure => 0.5 Torr to 500 Torr;

[0043] • Temperature => 200℃ to 1000℃;

[0044] • H2 flow rate => 0.1 to 10 liters per minute;

[0045] • Carrier gas flow rate => 0.001 to 1 liter per minute; and

[0046] • Precursor ampoule temperature => 10℃ to 180℃.

[0047] The deposition of tungsten on various substrates depends directly on the concentration of the WOCl4 precursor (referred to as [WOCl4] in this paper), the substrate characteristics, and the substrate temperature. Generally, but not strictly, a WOCl4 concentration of <1000 ppm is required for tungsten film growth in CVD processes as described in this paper.

[0048] Alternatively, according to the method of this disclosure, WOCl4 is biased towards substrate etching under the following conditions:

[0049] • Pressure => 0.5 Torr to 500 Torr;

[0050] • Temperature => 200℃ to 1000℃;

[0051] • H2 flow rate => 0.1 to 10 liters per minute;

[0052] • Carrier gas flow rate => 0.001 to 1 liter per minute; and

[0053] • Precursor ampoule temperature => 10℃ to 180℃.

[0054] The etching performance of various substrates depends directly on the concentration of the precursor [WOCl4], substrate characteristics, and substrate temperature. Generally, but not strictly speaking, in continuous exposure mode (i.e., CVE = Chemical Vapor Etching) processes, the concentration of [WOCl4] is >1000 ppm. The precursor concentration depends on the combination of [WOCl4], substrate material, and substrate temperature.

[0055] Furthermore, or alternatively, according to the method of this disclosure, tungsten is selectively deposited onto a metal conductor film by exposing a substrate of a film comprising Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, Cu, Ir, SiN, TiN, and SiO2 films to (i) WOCl4 along with a carrier gas supplied from the precursor ampoule, and (ii) a co-reactant reducing gas in the reaction zone.

[0056] The pressure in the reaction zone is approximately 0.5 Torr to 500 Torr;

[0057] The substrate temperature is approximately 200°C to 1000°C.

[0058] The reducing gas flow rate is approximately 0.1 to 10 liters per minute.

[0059] • The carrier gas flow rate is approximately 0.001 to 1 liter per minute.

[0060] The concentration of [WOCl4] is less than 1000 ppm, and

[0061] The precursor ampoule temperature ranges from approximately 10°C to approximately 180°C.

[0062] Due to these process conditions, tungsten is selectively deposited on metal conductor films (e.g., W, Mo, Co, Ru, Cu, Ir) and other suitable metal conductor films, rather than on nitride and / or dielectric oxide films.

[0063] Example

[0064] Table 1

[0065]

[0066]

[0067] The results of Examples 1 through 5 are summarized in Table 1 above, with measurements taken before and after X-ray fluorescence (XRF). Positive (+) values ​​indicate tungsten film deposition, and negative (-) values ​​indicate substrate film etching. In these experiments, the WOCl4 ampoule temperature was set to 90°C, the Ar carrier gas flow rate was set to 100 sccm (standard cubic centimeters per minute, i.e., flow rate), and the WOCl4 was exposed to the substrate for approximately 600 seconds. As can be seen in the table, Al2O3 exhibited the highest etch rate per minute of exposure in this study due to the lack of competing tungsten deposition processes observed at higher temperatures. Furthermore, the etch rate was observed to depend on the precursor [WOCl4] concentration, substrate characteristics, and temperature (T). sub (i.e., substrate temperature). Higher precursor concentrations and higher substrate temperatures lead to substrate etching, while tungsten deposition is observed when the precursor concentration is too low to allow for substrate etching. Tungsten deposition was observed at 550°C. and 650℃ This occurs below, while the substrate is etched at 400°C. This occurs under certain conditions. In these examples of tungsten deposition, the resistivity of the resulting films was found to be as low as 11.5 μΩ-cm on tungsten substrates (Example 3) and as low as 26.7 μΩ-cm on TiN substrates. Furthermore, it was shown that high precursor concentrations led to columnar crystal growth on the tungsten substrates (i.e., isolated grains), and at higher T... sub It has a high resistivity (19 μΩ-cm).

[0068] As can be seen from the data in Table 1, selective deposition of tungsten metal onto tungsten or other suitable metal conductor films (e.g., Mo, Co, Ru, Ir, and Cu), rather than onto nitride and / or dielectric oxide films, can be achieved by carefully controlling process conditions during deposition. In some embodiments, the substrate may be pre-etched prior to selective deposition to enhance contact resistance and film adhesion properties. While it may not be desirable to be bound by theory, selective deposition of tungsten metal onto other suitable metal conductor films (e.g., Mo, Co, Ru, Ir, and Cu), rather than onto nitride and / or dielectric oxide films, can also be achieved by carefully controlling process conditions during deposition.

[0069] Table 2

[0070]

[0071] In Examples 6 through 10, the results are summarized in Table 2, with the argon carrier gas flow rate set at 100 sccm, the H2 gas flow rate set at 2000 sccm, and the tungsten CVD deposition time at 600 seconds. From the data in Table 2, it can be observed that WOCl4 etches titanium nitride under most test conditions. It can also be observed that at lower precursor concentrations, for higher T… sub The rate / degree of titanium nitride etching increases, while tungsten deposition only occurs at 650°C.

[0072] Table 3a (H2 only)

[0073]

[0074] Table 3b (Argon only)

[0075]

[0076] In Examples 11 to 20, the results are summarized in Tables 3a and 3b, where the argon carrier gas used was 100 sccm; additionally, in Table 3a, H2 gas was introduced at a rate of 2000 sccm (without other argon gas). In Table 3b, in addition to adding argon carrier gas at a rate of 100 sccm (without other H2 gas), the argon purge gas was introduced at a rate of 2000 sccm. Generally, the etching rate of Al2O3 in Ar is lower than when using a co-reactant gas flow of H2. This data also shows that Al2O3 is etched faster in argon compared to a combination of H2 at low substrate temperature and low chamber pressure (higher WOCl4 concentration).

[0077] Table 4

[0078]

[0079] *unknown

[0080] Examples 21 to 25 pertain to attempts at etching SiO2. Results are summarized in Table 4. In these experiments, the argon carrier gas used was 100 sccm, and the H2 gas used was 2000 sccm. Tungsten deposition occurred only at 650°C with lower precursor concentrations. The resistivity was approximately 18 μΩ-cm. No SiO2 etching was observed at any temperature for [WOCl4] < 1000 ppm. Without being bound by theory, based on the mechanics of the etching process, it is believed that in some instances, at higher concentrations of the WOCl4 precursor, SiO2 etching may occur slowly.

[0081] Table 5

[0082]

[0083] In Examples 26 to 34, the results are shown in Table 5 above, where titanium nitride substrates were subjected to pulsed CVD conditions using a precursor chamber pressure of 80 Torr, an argon carrier gas of 100 sccm, and a H2 gas concentration of 2000 sccm (continuous). The WOCl4 precursor pulse lasted for 1 second in a 40-second cycle interval. The number of pulse cycles for the WOCl4 precursor were 1, 5, 10, 15, and 25 cycles, respectively. This data shows that in this pulsed CVD process, the titanium nitride etching rate is quite high in the first cycle and decreases sharply after >5 cycles. Tungsten deposition begins to occur as the number of cycles increases beyond 10. Additionally, a lower substrate temperature (430°C) increases the titanium nitride etching rate by approximately 10% in the first cycle.

[0084] Table 6

[0085]

[0086] The results of experiments 35 through 37 are summarized in Table 6. The data were generated using pulsed chemical vapor deposition (PCVD) conditions with WOCl4 as the precursor, including a precursor chamber pressure of 80 Torr and an argon carrier gas rate of 100 sccm. In examples 35 through 37, H2 gas was injected into the reactor chamber at a constant rate of 2000 sccm. In examples 35 through 37, increasing the WOCl4 precursor "work time" for a 10-second work time increased the titanium nitride etching rate by 30%. Additionally, the tungsten deposition rate increased with increasing work time of 15 cycles. Note: The increased loss of TiN may be due to the loss of X-ray signal through the tungsten film.

[0087] Table 7

[0088]

[0089] The examples in Table 7 illustrate the etching of titanium nitride substrates under CVD conditions using argon carrier gas at 100 sccm, H2 at 2000 sccm (continuous), and tungsten deposition times of 600, 600, 300, 300, and 300 s, respectively. This data demonstrates that increasing the precursor (WOCl4) concentration increases the etching rate; the precursor concentration can be increased by reducing the chamber pressure, decreasing the reducing gas concentration of the co-reactants, and / or increasing the ampoule temperature.

[0090] Table 8a

[0091]

[0092] Table 8b

[0093]

[0094] For Examples 42 to 47, the data are summarized in Tables 8a and 8b. The precursor was WOCl4, the H2 gas flow rate was 2000 sccm, the tungsten deposition time was 300 s, the chamber pressure was 10 Torr, and the obtained tungsten thickness was... The data in Table 8a show that, since the reaction is carried out under a pressure of 10 Torr in a mass transfer-limited scheme, the titanium nitride etching rate does not change with T. sub Changes. Table 8b shows that increasing the precursor carrier gas increases the precursor concentration and the titanium nitride etching rate, thus indicating that the mass transfer rate of etching is limited at 430°C. Furthermore, the mass transfer of titanium nitride etching is limited at a pressure of 10 Torr, and the surface reaction rate is limited at a pressure of 80 Torr.

[0095] Table 9

[0096]

[0097]

[0098] In Examples 48 to 50 (ALE process), the data are summarized in Table 9, with WOCl4 as the precursor, an Ar carrier gas flow rate of 200 sccm, an H2 gas flow rate of 2000 sccm, an argon purge gas flow rate of 500 sccm, a tungsten deposition time of 60 cycles, and a substrate temperature of 520°C. This data shows that the deposition rate of tungsten on titanium nitride decreases with decreasing pressure (from 80 Torr to 20 Torr) (i.e., with increasing WOCl4 concentration). Additionally, the TiN etching rate increases with decreasing pressure; however, 40 Torr indicates the transition between deposition and etching. Under these process conditions, the resistivity of the deposited tungsten film is excellent. This data also illustrates that substrate etching and deposition can occur simultaneously without changing the experimental conditions and can compete in real time.

[0099] Table 10

[0100]

[0101] In Examples 51 and 52, the data are summarized in Table 10. The precursor was WOCl4, the argon carrier gas flow rate was 200 sccm, the H2 gas flow rate was 2000 sccm, the argon purge gas flow rate was 500 sccm, the tungsten deposition time was 60 cycles, the pressure was 20 Torr, and the substrate temperature was 520°C. This data confirms that increasing the WOCl4 "working time" increases both the tungsten deposition rate and the titanium nitride etching rate on the titanium nitride substrate. Under these process conditions, the tungsten resistivity showed almost no change.

[0102] Table 11

[0103]

[0104] In Examples 53 and 54, the data are summarized in Table 11. The precursor was WOCl4, the Ar carrier gas flow rate was 200 sccm, the H2 gas flow rate was 2000 sccm, the argon purge gas flow rate was 500 sccm, the pressure was 20 Torr, and the substrate temperature was 520°C. This data shows that there is approximately 30 cycles of nucleation delay for depositing a tungsten layer on titanium nitride. Furthermore, after covering the surface with tungsten, the deposition rate increases with the number of cycles. The etching rate decreases with time and also decreases with increasing tungsten coverage. Good tungsten resistivity was observed for these tungsten films.

[0105] Table 12

[0106]

[0107]

[0108] For Examples 55 through 57, the data are summarized in Table 12. The precursor was WOCl4, the Ar carrier gas flow rate was 200 sccm, the H2 gas flow rate was 1000 sccm, the argon purge gas flow rate was 500 sccm, and the Al2O3 substrate temperature was 650°C. Example 55 was run for 40 cycles, and Examples 56 and 57 were run for 30 cycles. This data shows that the tungsten deposition rate decreases with decreasing pressure, while the Al2O3 etching rate increases. As expected, due to incomplete coverage and unoptimized morphology, the thinner the tungsten film, the higher the resistivity.

[0109] Table 13

[0110]

[0111] For Examples 58 to 60, the data are summarized in Table 13, with WOCl4 as the precursor, an H2 gas flow rate of 1000 sccm, and an Al2O3 substrate temperature of 650°C. This data shows that both the tungsten deposition rate and the Al2O3 etching rate decrease with decreasing argon carrier gas flow rate and increasing argon purge gas flow rate. The resistivity varies from approximately 23 to 59 μΩ-cm.

[0112] Table 14

[0113]

[0114] For Examples 61 to 63, the data are summarized in Table 14. The precursor was WOCl4, the Ar carrier gas flow rate was 50 sccm, the H2 gas flow rate was 1000 sccm, the argon purge gas flow rate was 700 sccm, and the Al2O3 substrate temperature was 650°C. This data shows that the tungsten deposition rate increases with increasing cycle number as more tungsten covers the Al2O3 surface. The Al2O3 etching rate also increases, but this is due to the absorption of X-rays by the tungsten film on top of the Al2O3. As expected, the resistivity decreases with increasing tungsten film thickness due to the reduction in pinholes or voids in the tungsten film.

[0115] Adhesion test results according to ASTM D 3359-02 show excellent adhesion, specifically, adhesion to titanium nitride substrates deposited at 650°C. Film and deposited on alumina substrate The tungsten film was not peeled off from the substrate.

[0116] Referring to the attached figures and the experimental data listed above, Figure 1 It is the Al2O3 etching rate A graph showing the effect of substrate temperature (°C). This data indicates that the Al2O3 etching rate is approximately twice that when co-reacting with H2, compared to reacting with argon alone. Furthermore, the etching rate decreases with decreasing pressure. Lower pressure increases the concentration of WOCl4, which should increase etching. This data suggests that deposition increases with increasing substrate temperature, thus limiting the reaction rate, and that residence time also determines the etching rate (see Table 1).

[0117] Figure 2 This is a graph showing the etching rates of TiN at temperatures of 430, 475, and 520 °C. (Plotting the TiN etching rates) A graph showing the number of cycles. See also the data provided in Tables 1 and 2. This data was generated using the following pulsed chemical vapor deposition conditions: 80 Torr pressure, 100 sccm of Ar carrier gas and 2000 sccm of H2 flow rate for the co-reactants, a 1-second WOCl4 pulse, and a total cycle time of 40 seconds. The data for substrate temperatures of 430 and 475 °C illustrate the operation in a mass transfer rate-limited process, as the etch rate does not increase with increasing substrate temperature. Furthermore, the amount of etch is limited, and the largest portion of the etch occurs in the first cycle and gradually decreases over the next five cycles.

[0118] Figure 3 This is a graph showing tungsten deposition on TiN at temperatures of 430, 475, and 520 °C using WOCl4 as a precursor. This data was generated using the following pulsed chemical vapor deposition conditions: 80 Torr pressure, 100 sccm of argon carrier gas, and 2000 sccm of H2 flow rate. [Plotting tungsten deposition...] The graph shows the relationship between the number of cycles. This data illustrates that tungsten deposition occurs after 5 cycles at operating temperatures of 475°C and 520°C, but takes longer (after 10 cycles) at an operating temperature of 430°C. The substrate temperature is indicated by the nucleation delay.

[0119] Figure 4 This paper describes the pulsed CVD deposition of tungsten on titanium nitride using WOCl4 as a precursor. (The image is then plotted...) A graph showing tungsten deposition relative to the pulsed "operation time" in seconds for the precursor. This data illustrates that tungsten deposition increases significantly (~6x) within a 10-second operation time for the precursor. Pulsed CVD conditions included a pressure of 80 Torr, an argon carrier gas flow rate of 100 sccm, and an H2 flow rate of 2000 sccm (continuous). Under these conditions, and at a substrate temperature (T... sub At a temperature of 430°C, no tungsten deposition was observed, but titanium nitride film etching was observed. (See Table 6)

[0120] Figure 5 This paper illustrates the effect of pulse "off time" on the exposure of a titanium nitride substrate to pulsed CVD conditions using WOCl4 as a precursor. Other conditions included a pressure of 80 Torr, an argon carrier gas flow rate of 100 sccm, and a continuous H2 flow rate of 1000 sccm. A graph of the titanium nitride etching rate versus pulse "off time" is plotted. With increasing off time, the ampoule temperature increases due to the reduced Ar flow rate and subsequent cooling, thus increasing the precursor concentration. This graph also illustrates that the titanium nitride etching rate is directly dependent on the WOCl4 precursor concentration; furthermore, under these conditions, no tungsten deposition occurs due to the short exposure time (5 cycles).

[0121] Figure 6 This is a simplified drawing of an "ALD" (or "ALE" in the case of etching) process used to practice the methods of this disclosure. WOCl4 and the co-reactant (i.e., the reducing gas) are pulsed "on" for a portion of the cycle time. A vacuum or inert gas purging occurs between the precursor and co-reactant pulses. This cycle is repeated multiple times to produce a specific film thickness (or achieve the desired amount of etching).

[0122] Figure 7 This is a simplified drawing of a "CVD" (or "CVE" in the case of etching) process for practicing the methods of this disclosure. WOCl4 and co-reactants are continuously fed into the reaction zone until the desired amount of deposition (or etching) has occurred.

[0123] Figure 8This is a simplified drawing of a "pulsed CVD" (or "CVE" in the case of etching) process for practicing the methods of this disclosure. During a given time period, a WOCl4 precursor is injected into the reaction zone in a pulsed manner, followed by a "shutdown" period while co-reactants are continuously fed into the reaction zone. In this way, during these periods, when the pulses are "shut down," the co-reactants must be purged from the reaction zone of the precursor.

[0124] Figure 9 This is a simplified drawing of the reaction chamber suitable for carrying out the methods of this disclosure.

[0125] Other aspects of this disclosure include the following:

[0126] Aspect 1 is a method comprising exposing a substrate to WOCl4 and a reducing gas in a reaction zone under the following conditions:

[0127] (a) A substrate is controlled to be etched under a first set of process conditions, wherein the substrate comprises a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, Ir, Cu, SiO2 and SiN films;

[0128] (b) Under the second set of process conditions, tungsten is controllably deposited on the surface of a substrate, wherein the substrate comprises a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, Ir, Cu, SiN, TiN, and SiO2 films; or

[0129] (c) Under the third set of process conditions, tungsten is selectively deposited on a metallic conductive W, Mo, Co, Ru, Ir, or Cu substrate, rather than on an adjacent nitride or dielectric oxide film.

[0130] Aspect 2 is the method of aspect 1, wherein the first set of process conditions includes a substrate temperature range of about 200°C to about 1000°C, a WOCl4 concentration of about 800 ppm to about 20,000 ppm, and a pressure of about 0.5 to about 500 Torr.

[0131] Aspect 3 is the method of aspect 1, wherein the second set of process conditions includes a substrate temperature range of about 200°C to about 1000°C, a WOCl4 concentration of about 5 ppm to about 1200 ppm, and a pressure of about 0.5 to about 500 Torr.

[0132] Aspect 4 is the method of aspect 1, wherein the reducing gas is selected from hydrogen, hydrazine or alkyl hydrazine.

[0133] Aspect 5 is the method of aspect 2 or 3, wherein the reducing gas is hydrogen, and the hydrogen is fed into the reaction zone at a rate of about 0.1 liters to about 10 liters per minute.

[0134] Aspect 6 is a method comprising exposing a substrate containing a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, and SiN films in a reaction zone to (i) WOCl4 along with a carrier gas supplied from a precursor ampoule, and (ii) a reducing gas, wherein the pressure in the reaction zone is about 0.5 to 500 Torr; the substrate temperature is about 200°C to 1000°C; the reducing gas flow rate is about 0.1 to 10 liters per minute; the carrier gas flow rate is about 0.001 to 1 liter per minute; the concentration of WOCl4 in the reaction zone is greater than 1000 ppm; and the precursor ampoule temperature is about 10°C to about 180°C, thereby etching the substrate containing a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, and SiN films.

[0135] Aspect 7 is the method of aspect 6, wherein the concentration of WOCl4 in the reaction zone is from about 1,000 ppm to about 10,000 ppm.

[0136] Aspect 8 is a method of aspect 6, wherein the substrate is exposed to a continuous flow of WOCl4 precursor and reducing gas.

[0137] Aspect 9 is a method of aspect 6, wherein the substrate is exposed to a continuous flow of reducing gas while the WOCl4 precursor is pulsed into the reaction zone for a predetermined time period.

[0138] Aspect 10 is the method of aspect 9, wherein the WOCl4 precursor is pulsed into the reaction region for a period of 0.05 to about 20 seconds, followed by a shutdown period of 0.05 to about 120 seconds, and the required number of pulses are repeated until the required amount of etching has occurred on the substrate.

[0139] Aspect 11 is the method of aspect 9, wherein the WOCl4 precursor is pulsed into the reaction zone for a period of 0.1 to about 10 seconds, followed by a shutdown period of 1 to about 60 seconds.

[0140] Aspect 12 is the method of aspect 9, wherein the substrate is an Al2O3 film.

[0141] Aspect 13 is a method of aspect 6, wherein the substrate is subjected to the following sequential processes:

[0142] (i) Exposure to WOCl4 precursor, followed by

[0143] (ii) Purge with a vacuum or inert gas, then

[0144] (iii) Exposure to reducing gas, followed by

[0145] (iv) Purge with a vacuum or inert gas and repeat the sequence from (i) to (iv) until the desired amount of etching has occurred on the substrate.

[0146] Aspect 14 is the method of aspect 6, wherein the concentration of the WOCl4 precursor in the reaction zone is from about 2000 ppm to about 5000 ppm.

[0147] Aspect 15 is the method of aspect 6, wherein the substrate temperature is from about 300°C to about 450°C.

[0148] Aspect 16 is a method comprising exposing a substrate containing a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN, and SiO2 films in a reaction zone to:

[0149] (i) WOCl4, along with the carrier gas delivered from the precursor ampoule, and

[0150] (ii) Reducing gases

[0151] The pressure in the reaction zone is approximately 0.5 Torr to 500 Torr; the substrate temperature is approximately 200°C to 1000°C; the reducing gas flow rate is approximately 0.1 to 10 liters per minute; the carrier gas flow rate is approximately 0.001 to 1 liter per minute; the WOCl4 concentration is less than 1000 ppm; and the precursor ampoule temperature is approximately 10°C to approximately 180°C.

[0152] Tungsten is thus deposited on the surface of a substrate containing a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Ru, SiN, TiN and SiO2 films.

[0153] Aspect 17 is the method of aspect 16, wherein the concentration of WOCl4 in the reaction zone is from about 75 ppm to about 1000 ppm.

[0154] Aspect 18 is a method of aspect 16, wherein the substrate is subjected to the following sequentially:

[0155] (i) Exposure to WOCl4 precursor, followed by

[0156] (ii) Purge with a vacuum or inert gas, then

[0157] (iii) Exposure to reducing gas, followed by

[0158] (iv) Purge with a vacuum or inert gas and repeat the sequence from (i) to (iv) until the desired amount of tungsten has been deposited on the substrate.

[0159] Aspect 19 is a method of aspect 16, wherein the exposure is wherein the substrate is exposed to a continuous flow of WOCl4 precursor and reducing gas.

[0160] Aspect 20 is a method of aspect 16, wherein the exposure is wherein the substrate is exposed to a continuous flow of reducing gas while a WOCl4 precursor is pulsed into the reaction zone for a predetermined time.

[0161] Aspect 21 is the method of aspect 20, wherein the WOCl4 precursor is pulsed into the reaction region for a period of 0.1 to about 10 seconds, followed by a shutdown period of 1 to about 60 seconds, and the required number of pulses are repeated until the required amount of tungsten deposition has occurred on the substrate.

[0162] Aspect 22 is the method of aspect 16, wherein the concentration of the WOCl4 precursor in the reaction zone is from about 100 ppm to about 800 ppm.

[0163] Aspect 23 is the method of aspect 16, wherein the substrate temperature is from about 550°C to about 700°C.

[0164] Aspect 24 is a method for selectively depositing tungsten onto a metallic conductor film, comprising exposing a substrate containing a film selected from Al₂O₃, HfO₂, ZrO₂, W, Mo, Co, Ru, Cu, Ir, SiN, TiN, and SiO₂ films in a reaction zone to (i) WOCl₄ along with a carrier gas supplied from a precursor ampoule, and (ii) a co-reactant reducing gas, under processing conditions including: a pressure in the reaction zone of about 0.5 Torr to 500 Torr; a substrate temperature of about 200°C to 1000°C; a reducing gas flow rate of about 0.1 to 10 liters per minute; a carrier gas flow rate of about 0.001 to 1 liter per minute; and a [WOCl₄] concentration of less than 1000 ppm, wherein the precursor ampoule temperature is about 10°C to about 180°C, and

[0165] Tungsten is selectively deposited on metal conductor films (e.g., W, Mo, Co, Ru, Cu, Ir) and other suitable metal conductor films, rather than on nitride and / or dielectric oxide films.

[0166] Aspect 25 is a tungsten film, which has approximately To date The thickness is [thickness], and each has a resistivity of approximately 100 to approximately 50 μΩ-cm.

[0167] Aspect 26 is a tungsten film, which has approximately To date The thickness is approximately 50 to approximately 13 μΩ-cm.

[0168] Aspect 27 is a tungsten film, which has a greater than It has a thickness and a resistivity of approximately less than 15 μΩ-cm.

[0169] Therefore, several illustrative embodiments of this disclosure have been described, and those skilled in the art will readily recognize that other embodiments can be made and used within the scope of the appended claims. Many advantages of the invention covered by this document have been set forth in the foregoing description. However, it should be understood that in many respects, the invention is merely illustrative. Changes may be made in detail without departing from the scope of the invention. The scope of the invention is, of course, defined by the language expressed in the appended claims.

Claims

1. A method for depositing tungsten, comprising exposing a substrate to WOCl4 and a reducing gas in a reaction zone under the following conditions: (a) Controllably etching a substrate under a first set of process conditions, wherein the substrate comprises a film selected from Al2O3, TiN, HfO2, ZrO2, W, Mo, Co, Ru, Ir, Cu, SiO2, and SiN films; and (b) Tungsten is controllably deposited on the surface of the substrate under the second set of process conditions. The first set of process conditions includes a substrate temperature range of 200°C to 1000°C, a WOCl4 concentration of 800 ppm to 20,000 ppm, and a pressure of 0.5 to 500 Torr. The second set of process conditions includes a substrate temperature range of 200°C to 1000°C, a WOCl4 concentration of 5 ppm to 1200 ppm, and a pressure of 0.5 to 500 Torr.

2. The method according to claim 1, wherein the reducing gas is selected from hydrogen, hydrazine, or alkyl hydrazine.

3. The method according to claim 1, wherein the reducing gas is hydrogen, and the hydrogen is fed into the reaction zone at a rate of 0.1 to 10 liters per minute.

4. The method of claim 1, wherein the first set of process conditions includes exposing the substrate in a reaction zone to (i) WOCl4 together with a carrier gas supplied from the precursor ampoule, and (ii) a reducing gas, wherein the pressure in the reaction zone is 0.5 to 500 Torr; the substrate temperature is 200°C to 1000°C; the reducing gas flow rate is 0.1 to 10 liters per minute; the carrier gas flow rate is 0.001 to 1 liter per minute; the concentration of WOCl4 in the reaction zone is greater than 1000 ppm; and the precursor ampoule temperature is 10°C to 180°C.

5. The method of claim 4, wherein the substrate is subjected to the following sequence: (i) Exposure to WOCl4 precursor, followed by (ii) Purge with a vacuum or inert gas, then (iii) Exposure to reducing gas, followed by (iv) Purge with vacuum or inert gas and repeat steps (i) to (iv) until the desired amount of etching has occurred on the substrate.

6. The method of claim 4, wherein the substrate is exposed to a continuous flow of WOCl4 precursor and reducing gas.

7. The method of claim 4, wherein the substrate is exposed to a continuous flow of reducing gas while the WOCl4 precursor is pulsed into the reaction zone for a predetermined time period.

8. The method of claim 1, wherein the second set of process conditions includes exposing the substrate in the reaction zone to: (i) WOCl4, together with the carrier gas delivered from the precursor ampoule, and (ii) Reducing gases The pressure in the reaction zone is 0.5 Torr to 500 Torr; the substrate temperature is 200°C to 1000°C; the reducing gas flow rate is 0.1 to 10 liters per minute; the carrier gas flow rate is 0.001 to 1 liter per minute; the WOCl4 concentration is less than 1000 ppm; and the precursor ampoule temperature is 10°C to 180°C. Tungsten is thus deposited on the surface of the substrate comprising a film selected from Al2O3, HfO2, ZrO2, W, Mo, Co, Cu, Ru, Ir, SiN, TiN, and SiO2 films.

9. The method according to claim 8, wherein the concentration of WOCl4 in the reaction zone is from 75 ppm to 1000 ppm.

10. The method of claim 8, wherein the WOCl4 precursor is pulsed into the reaction region for a period of 0.05 to 20 seconds, followed by a shutdown period of 0.05 to 120 seconds, and the required number of pulses is repeated until the desired amount of deposition has occurred on the substrate.

11. The method of claim 10, wherein the WOCl4 precursor is pulsed into the reaction zone for a period of 0.1 to 10 seconds, followed by a shutdown period of 1 to 60 seconds.

12. The method of claim 8, wherein the substrate is subjected to the following sequence: (i) Exposure to WOCl4 precursor, followed by (ii) Purge with a vacuum or inert gas, then (iii) Exposure to reducing gas, followed by (iv) Purge with a vacuum or inert gas and repeat steps (i) to (iv) until the desired amount of tungsten deposition has occurred on the substrate.

13. The method of claim 8, wherein the exposure is wherein the substrate is exposed to a continuous flow of WOCl4 precursor and reducing gas.

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