TWI719269B - Deposition of metal films - Google Patents

Abstract

Methods to selectively deposit titanium-containing films on silicon-containing surfaces in high aspect ratio features of substrates comprise plasma-enhanced chemical vapor deposition (PECVD) process at a plasma powers in the range of about 1 to less than about 700 mWatts/cm² and frequencies in the range of about 10 kHz to about 50 MHz. The titanium films may be selectively deposited with a selectivity in the range of at least about 1.3:1 metallic silicon surfaces relative to silicon dioxide surfaces.

Description

Deposition of metal film

The specific example of the present invention generally relates to a method of depositing a metal film on a metallic surface. More specifically, the specific example of the present invention relates to a method of improving bottom film coverage, and further, selectively depositing metal on the surface of different materials (such as metal oxide, metal nitride, or metal-oxide-nitride) The film is on the metallic surface.

The integrated circuit can be manufactured by the process of producing a complex patterned material layer on the surface of the substrate. The production of patterned material on the substrate requires a controlled method for the deposition of the desired material. The selective deposition of a film on a surface relative to a different surface is beneficial for patterning and other applications.

As manufacturers strive to increase circuit density and quality, high-aspect-ratio voids including contacts, vias, lines, and other features used to form multi-level interconnections (for example, using cobalt, tungsten, or copper) continue in size Zoom out. Titanium is widely used as a silicide material. Selective titanium deposition is an ongoing goal to improve Rc (contact resistance) performance.

Plasma-enhanced chemical vapor deposition (PECVD) uses TiCl ₄ as a precursor to form titanium and is widely used in the semiconductor industry, but the conventional TiCl ₄ state, such as 600°C–700°C, shows poor performance The bottom of the high aspect ratio pores is covered, which decreases with the size.

There is a continuing need to provide silicide layers in desired locations, including bottom coverage and selective deposition of titanium films.

One or more specific examples of the present invention are related to processing methods, including during plasma enhanced chemical vapor deposition (PECVD) processing in a processing chamber, selectively depositing a metal film on the first surface of the substrate with respect to the second surface. Above, the second surface and the first surface of the substrate are of different materials.

An additional specific example of the present invention relates to a processing method, including positioning the surface of the substrate in the processing chamber. There is at least one feature on the surface of the substrate, and the at least one feature creates a gap with a bottom, a top, and a sidewall. The bottom includes a metallic element or alloy, and any one of the metallic element or alloy is optionally doped, Whereas the sidewalls include metal oxide, metal nitride, or metal-oxide-nitride, each of the metal oxide, metal nitride, or metal-oxide-nitride is optionally doped with carbon. During the plasma-enhanced chemical vapor deposition (PECVD) process, the surface of the substrate is exposed to the metal halide precursor gas and the hydrogen-containing reductive co-reacting precursor at a substrate temperature in the range of about 300°C to less than 500°C. sidewall range from about 1 to less than about 700 mW / cm ² in plasma power, with respect to the characteristics of the metal film is formed over the bottom.

A further specific example of the present invention relates to a processing method, including positioning a substrate having a first surface and a second surface in a processing chamber, the first surface being: metallic silicon (Si), metallic germanium (Ge), or SiGe alloy, each of metallic silicon (Si), metallic germanium (Ge), or SiGe alloy is optionally doped with phosphorus (P), arsenic (As), and/or boron (B), and this The second surface is metal oxide, metal nitride, or metal-oxide-nitride, and each of the metal oxide, metal nitride, or metal-oxide-nitride is optionally doped with carbon. The metal precursors include titanium halides; zirconium halides, and/or hafnium halides; hydrogen; and carrier gas flows into the processing chamber. The metal precursor and hydrogen are energized by the application of plasma power in the range of about 1 to less than about 700 mW/cm ² and the frequency in the range of about 10 kHz to about 50 MHz. The energized metal precursor and hydrogen are reacted to selectively deposit a metal film on the first surface with respect to the second surface with a selectivity of at least about 10:1.

A specific example of the present invention provides a method of depositing a titanium film on a silicon-containing surface. Ti-silicide is used as a silicide forming layer in high aspect ratio pores for contact applications. When the node size is reduced to less than 20 nm and metal gates are used, the thermal budget of the substrate processing temperature is reduced (<500°C). The present invention advantageously improves the Ti bottom coverage of the narrow trench and _{the deposition selectivity on Si (active bonding surface) and SiO 2} (sidewall and field region) to reduce the contact resistance at a deposition temperature less than 500°C. The improved bottom coverage of Ti by PECVD and _{the selective deposition between Si and SiO 2} allow a wider space for post-metal filling processing and improved device performance.

When used in the scope of this specification and the accompanying patent application, the terms "substrate" and "wafer" are used interchangeably, and both refer to a surface or a part of a surface on which processing can be performed. Those skilled in the art can also understand that a substrate can also be referred to as a part of the substrate, unless the context clearly indicates otherwise. In addition, referring to deposition on a substrate can mean both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

When "substrate" is used here, it refers to any substrate or the surface of a material formed on the substrate, and film processing can be performed on the surface of the substrate or material during the manufacturing process. For example, the substrate surface on which processing can be performed includes materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass , Sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. The substrate includes (not limited to) a semiconductor wafer. The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal and/or bake the surface of the substrate. In addition to the film treatment directly on the surface of the substrate itself, in the present invention, any of the film treatment steps disclosed can also be performed on the lower layer formed on the substrate as disclosed in more detail later, and the term "substrate surface" It is intended to include this lower layer as the context dictates. So for example, where the film/layer or part of the film/layer has been deposited on the surface of the substrate, the exposed surface of this newly deposited film/layer becomes the surface of the substrate. What is contained on a given substrate surface will depend on the type of film to be deposited and the specific chemistry used. In one or more embodiments, the surface of the first substrate will include metal, and the surface of the second substrate will include dielectric, or vice versa. In some specific examples, the surface of the substrate may include specific functional groups (for example, -OH, -NH, etc.).

When used in the scope of this specification and the accompanying patent application, the terms "reactive gas", "precursor", "reactant", and the like are used interchangeably to mean a gas that includes species that react with the surface of the substrate.

Chemical vapor deposition (CVD) processing, including plasma enhanced chemical vapor deposition (PECVD), is different from atomic layer deposition (ALD). The ALD process is a self-limiting process in which a binary (or higher) reaction is used to deposit a single material layer. This process continues until all available active parts on the surface of the substrate have been reacted. The CVD process is not a self-limiting process, and the film can be grown to any predetermined thickness. PECVD relies on the use of energy in the plasma state to create more reactive free radicals.

Embodiments of the present invention provide processing methods to provide titanium layers in desired locations, including improved bottom coverage and selective deposition of titanium films in high aspect ratio features. When used in this specification and the scope of the appended application, the terms "selective deposition of" and "selectively formed" a film on a surface relative to another surface, and the like, mean the first amount The film of is deposited on the first surface and the second amount of film is deposited on the second surface, where the second amount of film is less than the first amount of film or is not present. The term "over" used here does not mean the physical orientation of a surface on top of another surface, but the thermodynamics or dynamics of a chemical reaction of a surface relative to the other surface The nature of the relationship. For example, the _{selective deposition of a titanium film on the silicon (Si) surface relative to the silicon dioxide (SiO 2} ) surface means that the titanium film is deposited on the Si surface and less titanium film is deposited on the SiO ₂ surface; Or the formation of this titanium film on the Si surface is thermodynamically or kinetically advantageous _{relative to the formation of the titanium film on the SiO 2 surface.} In other words, that this film can be selectively deposited on the first surface with respect to the second surface means that the deposition on the first surface is advantageous relative to the deposition on the second surface.

The specific example of the present invention relates to a method of depositing a metal film on a metallic surface preferentially with respect to a surface of a different material using PECVD. Fig. 1 shows a process flow diagram of a process 100 according to one or more specific examples of the present invention. For FIG 1, the metal film comprises titanium, the metal surface contains Si, and this different material comprises SiO _x or SiN. The metal film of the present invention may include, but is not limited to, titanium, zirconium, and/or hafnium. These metal films can be optionally doped with dopants, including but not limited to phosphorus (P), arsenic (As), and/or boron (B). The metallic surface may include, but is not limited to, Si, Ge, and/or SiGe. The surface of different materials may include, but is not limited to _{, silicon oxide (SiO x} ), silicon nitride (SiN), silicon oxide-nitride (SiON), each of which is optionally doped with carbon. Figure 2 is a partial cross-sectional view of a substrate with features and Figure 3 is a partial cross-sectional view of selective deposition of a titanium film in the features. 1 to 3, a substrate 200 including a feature 210 having a bottom surface 212 and sidewalls 214, 216 is provided for processing at 110. In this particular embodiment, the bottom surface comprises a sidewall comprising Si and SiO _x or SiN. As used herein, the term "provided" means that the substrate is placed in a location or environment for further processing. For illustrative purposes, certain figures show a substrate with a single feature; then, those skilled in the art will understand that there can be more than one feature. The shape or contour of the feature 210 can be any suitable shape or contour, including but not limited to (a) vertical sidewall and bottom surface, (b) tapered sidewall, (c) under-cutting, (d) cavity (reentrant) contour, (e) arcuate, (f) micro-trenching, (g) curved bottom surface, and (h) notch. When used here, the term "feature" means any deliberate surface irregularity. Suitable examples of features include, but are not limited to, trenches and holes with top, two side walls and bottom, and peaks with top and two side walls. The features can have any suitable aspect ratio (the ratio of the depth of the feature to the width of the feature). In some specific examples, the aspect ratio is greater than or equal to about 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, or 40:1.

At 120, in the first chamber, the substrate 200 is cleaned to remove native oxide, leaving a clean substrate surface. The native oxide can be removed by any suitable technique, including but not limited to a dry etching process ^{known as SiConi™ etching.} SiConi ^TM etching is a remote plasma-assisted dry etching process that involves simultaneous exposure of the substrate to H ₂ , NF ₃ and NH ₃ plasma by-products. The remote plasma excitation of hydrogen and fluorine species allows substrate processing without plasma damage. SiConi ^TM etching mainly conforms and selectively faces the silicon oxide layer, but does not etch silicon quickly, regardless of whether the silicon is in an amorphous, crystalline or polycrystalline state.

The substrate 200 has a (clean) substrate surface 220. At least one feature 210 forms an opening in the substrate surface 220. The features 210 extend from the substrate surface 220 to a depth D to a bottom surface 212, which includes silicon (Si). The feature 210 has a first side wall 214 and a second side wall 216 that define the width W of the feature 210. The sidewalls include silicon oxide (SiO _x ), such as _{silicon dioxide (SiO 2} ) or silicon nitride (SiN). The open area formed by the side wall and the bottom is also called a gap.

At 130 of FIG. 1, in the second chamber, Si and SiO _x / SiN surfaces exposed to PECVD deposition process using titanium precursors with a reducing agent and optionally a carrier gas. At 140 in FIG. 1, a titanium film 230 is selectively deposited on the Si surface _{relative to the SiO x /SiN surface.} At 150 in Figure 1, there is optional N ₂ , H ₂ , and/or NH ₃ plasma treatment or immersion. In a specific example, the formation of the titanium film 230 includes exposing the surface of the substrate to a titanium precursor and a reducing agent under the condition of plasma generation. Regarding the use of titanium chloride and hydrogen, without being bound by any specific theory of operation, it is expected that titanium chloride ^{reacts with H +} /H* species to deposit a titanium film on the substrate. The titanium film is formed on the characteristic Si and SiO _x /SiN surface. The unreacted titanium chloride is expected to _{be a titanium film formed on the SiO x} /SiN surface by etching to selectively deposit the titanium film on the Si surface. As a result of the etching in the selective deposition, the titanium film can be equally or unequally formed on the Si and SiO _x /SiN surfaces. In some specific examples, compared to the SiO _x /SiN surface, the titanium film is advantageously formed on the Si surface, and etching increases this selectivity.

The selectivity of this deposition is at least about 1.3:1. This selectivity can be in the range of about 1.3:1 at least about 100:1. In some specific cases, the selectivity is greater than or equal to about 1.5:1, 2:1, 5:1, 8:1, 10:1, 15:1, 20:1, 25:1, 50:1 or More.

According to one or more specific examples, the metal film has a thickness in the range of about 10Å to about 100Å above the bottom metallic/alloy surface and on the sidewall surface (metal oxide, metal nitride, metal-oxide, nitrogen The thickness of 10Å to ~0Å above the compound).

The processing chamber can be any chamber suitable for PECVD. The fluid precursor is supplied to the processing chamber, and the fluid precursor is then excited by the plasma power in a region of the chamber. There is a power supply electrically coupled to the processing chamber, and the power supply can be configured to deliver an adjustable amount of power to the chamber depending on the processing.

The metal precursor may include a metal halide. The halide can be any suitable halogen. The metal halide can be a mixture of different halogens or essentially Are the same halogen atoms. In some specific examples, the metal halide contains essentially only chlorine atoms. As used herein, "substantially only" means the halogen species having greater than or equal to about 95 atomic percent. In some embodiments, the halogen is one or more of fluorine, chlorine, bromine or iodine. In some specific examples, there are substantially no fluorine atoms; meaning that there are less than about 1% based on all halogen atoms.

In one or more specific examples, the metal halide is a metal chloride. The metal chloride can be a titanium oxidation state or a mixture that is substantially all in the same oxidation state (ie, >95% of the same oxidation state on an atomic basis). For example, titanium chloride TiCl _x may be a mixture of titanium oxidation state or substantially all of the same oxidation state (ie, >95% of the same oxidation state on an atomic basis). For example, titanium chloride may be _{a mixture of TiCl 3} and TiCl ₄ species or other species. Other metal chlorides include zirconium chloride and hafnium chloride.

The reducing agent includes a reducing co-reactant, which may be a hydrogen-containing precursor. The hydrogen-containing precursor may include _{at least one precursor selected from H 2} , NH ₃ , hydrocarbons, or the like. In some embodiments, the first precursor includes hydrogen (H ₂ ) and the first precursor is energized to generate H ⁺ and H* species. In some specific examples, hydrogen ions and free radicals form part of the plasma.

The deposited metal film may contain metal or consist mainly of metal, such as titanium, zirconium, or hafnium. As used herein, the term "mainly composed of" means that the film is greater than or equal to about 95 atomic percent of the specific component. In some embodiments, the metal film is greater than about 96, 97, 98, or 99 atomic percent of the specific composition.

Regarding the formation of the metal film, the metal precursor and the reducing agent can be co-flowed or alternately pulsed together with an optional carrier gas into the PECVD processing chamber to form a direct plasma. An example carrier gas is Ar. The substrate can be heated to a temperature ranging from about 50°C to about 500°C, preferably from about 100°C to less than 500°C, from about 300°C to less than 500°C, and more preferably from about 300°C to about 500°C. 440°C.

The plasma power can be in the range of about 1 to less than about 700 mW/cm ² , or about 70 to less than about 350 mW/cm ² , or even about 90 mW/cm ² and all values in the foregoing range And sub-range. The frequency can be in the range of about 10 kHz to about 50 MHz, or 350 kHz to 40 MHz, or even about 13.56 MHz and all values and sub-ranges in the foregoing range. The duty cycle can be in the range of 1 to 90% and all values and sub-ranges in the aforementioned range. The plasma power can be pulsed, providing power for a period of about 0.0000001 to about 90 seconds every about 0.00001 to about 100 seconds and all values and sub-ranges in the foregoing range.

When a carrier gas such as argon is used, the flow rate can be in the range of 3 to 400 sccm and all values and sub-ranges in the aforementioned range.

According to one or more specific examples, the substrate is subjected to processing before and/or after forming the metal layer. For example, in one or more specific examples, at 160 in FIG. 1, after the optional formation of the metal (eg titanium) layer, titanium nitride is deposited as the barrier layer. After breaking the vacuum, at 170, an optional RTA (rapid thermal annealing) is performed to form a titanium silicide layer. After breaking the vacuum, at 180, the depth and width of the remaining part of the feature is filled with tungsten or cobalt to form an interconnection. Titanium and titanium nitride processing can be performed in the same chamber or in one or more separate processing chambers. Alternatively, nitridation on the deposited Ti film can be performed by treatment with N ₂ , H ₂ , and/or NH ₃ with application of RF plasma or immersion.

In some embodiments, the substrate is moved from the first chamber to the next separate chamber for further processing. The substrate can be moved directly from the first chamber to a separate processing chamber, or the substrate can be moved from the first chamber to one or more transfer chambers and then to a separate processing chamber. Therefore, the processing equipment may include a plurality of chambers connected by a transfer station. Such equipment may be called "cluster tool" or "cluster system", and the like.

In general, the cluster tool is a modular system containing multiple chambers, which performs various functions, including substrate center finding and positioning, degassing, annealing, deposition, and/or etching. According to one or more specific examples, the cluster tool includes at least a first chamber and a central transfer chamber. The central transfer chamber can accommodate a robot that can transport substrates between and in the processing chamber and the loading lock chamber. The transfer chamber is generally maintained in a vacuum state and provides an intermediate stage for transferring substrates from one chamber to another and/or a loading lock chamber at the front end of the cluster tool. Two well-known clustering tools that can be used in the present invention are Centura® and Endura®, both of which are available from Applied Materials of Santa Clara, California. However, in order to perform specific steps of the processing as described herein, the exact arrangement and combination of the chambers can be changed. Other processing chambers that can be used include, but are not limited to, cyclical layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, Chemical cleaning, heat treatment such as RTP, plasma nitriding, degassing, positioning, hydroxylation and other substrate processing. By performing the processing in the chamber on the cluster tool, the substrate surface contamination due to atmospheric impurities can be avoided without oxidation before the subsequent film is deposited.

According to one or more specific examples, the substrate is continuously in a vacuum or "load gate" state and is not exposed to ambient air when moving from one chamber to the next. The transfer chamber is therefore under vacuum and is "pumped down" to vacuum pressure. The inert gas may be present in the processing chamber or the transfer chamber. In some embodiments, the inert gas is used as a purge gas to remove some or all of the reactants after forming a layer on the surface of the substrate. According to one or more specific examples, the purge gas is injected at the outlet of the deposition chamber to prevent the reactants from moving from the deposition chamber to the transfer chamber and/or additional processing chambers. Therefore, the flow of inert gas forms a curtain at the outlet of the chamber.

During processing, the substrate can be heated or cooled. This heating or cooling can be accomplished by any suitable means, including but not limited to changing the temperature of the substrate support (such as a susceptor) and flowing heating or cooling gas to the surface of the substrate. In some embodiments, the substrate support includes a heater/cooler, which can be controlled to conductively change the temperature of the substrate. In one or more specific examples, the applied gas (reactive gas or inert gas) is heated or cooled to locally change the substrate temperature. In some embodiments, the heater/cooler is positioned in the chamber adjacent to the surface of the substrate to convectively change the temperature of the substrate.

The substrate can also be fixed or rotating during processing. The rotating substrate can be rotated continuously or in a separate step manner. E.g, The substrate may be rotated throughout the process, or the substrate may be rotated in a small amount between exposure to different reactive gases or purge gases. Rotating the substrate (continuously or at intervals) during processing can help produce more uniform deposition or etching, by minimizing effects such as local variability in gas flow geometry.

Instance

Example 1

Control group

The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature and the sidewalls of the feature are silicon dioxide (SiO ₂ ). The substrate temperature is ~440°C and the pressure is 5 Torr. Titanium chloride (TiCl ₄ ), hydrogen (H ₂ ), and argon (Ar) are supplied to the PECVD chamber. After the deposition lasted ~300 seconds, the chamber was purged and evacuated. Table 1 below provides the status and completed titanium film formation.

(A)底部厚度%為底部膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。 (B)側壁厚度%為側壁膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。

(A) Bottom thickness% is the thickness of the bottom film divided by the thickness of the film formed on the substrate surface (not in the feature). (B) Sidewall thickness% is the thickness of the sidewall film divided by the thickness of the film formed on the substrate surface (not in the feature).

Example 2

The effect of power and carrier gas flow . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature and the sidewalls of the feature are silicon dioxide (SiO ₂ ). The substrate temperature is ~440°C and the pressure is 5 Torr. Titanium chloride (TiCl ₄ ), hydrogen (H ₂ ), and argon (Ar) are supplied to the PECVD chamber. After the deposition lasted ~600 seconds, the chamber was purged and evacuated. Table 2 below provides the status and completed titanium film formation.

(A)底部厚度%為底部膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。 (B)側壁厚度%為側壁膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。

(A) Bottom thickness% is the thickness of the bottom film divided by the thickness of the film formed on the substrate surface (not in the feature). (B) Sidewall thickness% is the thickness of the sidewall film divided by the thickness of the film formed on the substrate surface (not in the feature).

When comparing 2-A with 1-A, reducing the RF power improves bottom coverage and selectivity. Low RF power facilitate reducing Ti ⁺ to improve and reduce the bottom cover projection (overhang) and the minimum of H ⁺ / H * from the kinetic energy to reduce the oxygen reduction of SiO _2. Regarding 2-B compared to 2-A, increasing carrier gas flow results in 100% bottom coverage and comparable selectivity. The increase in the carrier gas increases TiCl ₄ , which etches unreacted Ti on the _{SiO 2} in the simultaneous deposition and etching process.

Figure 4 provides a graph of standardized titanium film thickness versus deposition time (seconds). Example 1-A (control) is the dotted line of the graph and Example 2-B is the solid line of the graph. Higher carrier gas rate and lower power resulting in faster compared to the above Si deposition on the SiO _2, which may improve the selectivity.

Example 3

The effect of stress . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature is silicon (Si) and the sidewall of the feature is silicon dioxide (SiO ₂ ). The substrate temperature is ~440°C and the pressure varies. Titanium chloride (TiCl ₄ ), hydrogen (H ₂ ), and argon (Ar) are supplied to the PECVD chamber. After deposition of 3-A lasting ~300 seconds and 3-B and 3-C lasting ~600 seconds, the chamber was purged and evacuated. Table 3 below provides complete status and a titanium film is formed over the region of SiN, is formed over the titanium silicide and the _side wall at the bottom of SiO on Si.

(A)底部厚度%為底部膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。

(A) Bottom thickness% is the thickness of the bottom film divided by the thickness of the film formed on the substrate surface (not in the feature).

Higher pressure reduces the kinetic energy of ^{Ti +} and H ^+. Achieve >200% bottom coverage and >10:1 selectivity. 5 to 7 respectively show the TEM images of the high aspect ratio structure after the formation _{of the TiSi x} films of Examples 3-A to 3-C.

Example 4

Pulse RF . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature is silicon (Si) and the sidewall of the feature is silicon dioxide (SiO ₂ ). The substrate temperature is ~440°C, the RF power at 350kHz is 65W (90mW/cm ² ), the carrier flow rate is 125 sccm, and the pressure is 5 Torr. Titanium chloride (TiCl ₄ ), hydrogen (H ₂ ), and argon (Ar) are supplied to the PECVD chamber. After deposition, the chamber is cleaned and evacuated. Table 4 below provides the status and completed titanium film formation.

(A)底部厚度%為底部膜的厚度除以形成在基板表面(不在特徵中)之上的膜的厚度。

(A) Bottom thickness% is the thickness of the bottom film divided by the thickness of the film formed on the substrate surface (not in the feature).

Pulsed RF improves selectivity and bottom coverage.

Example 5

High RF frequency . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature is silicon (Si) and the sidewall of the feature is silicon dioxide (SiO ₂ ). The substrate temperature is ~440°C, the carrier flow rate is 125 sccm, and the pressure is 5 Torr. Titanium chloride (TiCl ₄ ), hydrogen (H ₂ ), and argon (Ar) are supplied to the PECVD chamber. After the deposition lasted ~600 seconds, the chamber was purged and evacuated. Table 5 below provides the status and completed titanium film formation, where N/U represents non-uniformity.

13.56MHz improves selectivity with similar resistivity above Si.

Example 6

The effect of the work cycle . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature is silicon (Si) and the sidewall of the feature is silicon _{oxide (SiO x} ) or silicon nitride (SiN). The substrate temperature is ~450°C, the RF power at 13.56MHz is 65W (90mW/cm ² ), and the pressure is 5 Torr. 5 sccm of titanium chloride (TiCl ₄ ), 6000 sccm of hydrogen (H ₂ ), and 18,000 sccm of argon (Ar) are supplied to the PECVD chamber. After deposition, the chamber is cleaned and evacuated. Table 6 below provides the status, the finished thickness of the titanium film on the various surfaces, and the selectivity.

The selectivity over CVD SiN improves from about 3 up to about 21:1 with a low duty cycle. Note that the deposition rate also decreases. The selectivity over SiOx improved from about 10 up to about 19 with a low duty cycle.

Example 7

The effect of power on low duty cycles . The titanium film is formed on the surface of the unpatterned substrate. The substrate temperature is ~450°C, the RF power at 13.56MHz varies during a 10% duty cycle, and the pressure is 5 Torr. 5 sccm of titanium chloride (TiCl ₄ ), 6000 sccm of hydrogen (H ₂ ), and 18,000 sccm of argon (Ar) are supplied to the PECVD chamber. After deposition, the chamber is cleaned and evacuated. Table 7 below provides status, deposition time, and finish selectivity.

Even at low duty cycles, higher power increases TiSiN formation on the SiN substrate.

Example 8

The effect of pulse frequency generator and duty cycle . The titanium film is formed in the features on the surface of the substrate, where the bottom of the feature is silicon (Si) and the sidewall of the feature is silicon _{oxide (SiO x} ) or silicon nitride (SiN). The RF power is 65W (92mW/cm ² ). The number of duty cycles reflects how long the power is on and how long the power is off. This pulse is done at two different frequencies: 10kHz and 5kHz. The substrate temperature is ~450°C, the pulse frequency and duty cycle are variable, and the pressure is 5 Torr. 5 sccm of titanium chloride (TiCl ₄ ), 6000 sccm of hydrogen (H ₂ ), and 18,000 sccm of argon (Ar) are supplied to the PECVD chamber. After deposition, the chamber is cleaned and evacuated. Table 8 below provides the status, the finished thickness of the titanium film on various surfaces, and the selectivity.

The selectivity over CVD SiN improves from about 2.3 up to about 5.5:1 with a low duty cycle. Note that the deposition rate also decreases. The selectivity over SiOx improved from about 6 up to about 11 with a low duty cycle.

Although the foregoing is about specific examples of the present invention, other and further specific examples of the present invention can be conceived without departing from the basic scope of the present invention, and the scope of the present invention is determined by the scope of the following patent applications.

100: processing

110, 120, 130, 140, 150, 160, 170, 180: steps

200: substrate

210: Features

212: bottom surface

214, 216: side wall

220: substrate surface

230: titanium film

By referring to specific examples (some specific examples are shown in the accompanying drawings), a clearer description of the present invention briefly summarized above can be obtained, and in this way, the above-mentioned features of the present invention can be understood in detail. However, it will be noted that the accompanying drawings only illustrate typical specific examples of the present invention, and therefore are not considered to limit the scope of the present invention, as the present invention may tolerate other equally effective specific examples.

Figure 1 shows a processing flow chart of one or more specific examples of the present invention; Figure 2 is a partial cross-sectional view of a substrate with features; Figure 3 is a partial cross-sectional view of a titanium film selectively deposited in the features; 4 is a graph of normalized titanium film thickness versus deposition time (seconds); and FIGS. 5 to 7 provide transmission electron microscope (TEM) images of the high aspect ratio structure after the formation of the titanium film.

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210‧‧‧Features

212‧‧‧Bottom surface

214, 216‧‧‧ side wall

220‧‧‧Substrate surface

230‧‧‧Titanium film

Claims (17)

A method of depositing a metal film, the method comprising the following steps: during a plasma-enhanced chemical vapor deposition (PECVD) process in a processing chamber, at least about a second surface on a first surface relative to a second surface. 1.3:1. A selective and selective deposition of a metal film on the first surface of a substrate, wherein the second surface is a material different from the first surface, and the metal film contains greater than or equal to About 95 atomic percent of titanium (Ti), zirconium (Zr), or hafnium (Hf). The method according to claim 1, wherein the first surface includes a metallic element or alloy, any one of the metallic element or alloy is optionally doped, and the second surface includes a metal Oxide, a metal nitride, or a metal-oxide-nitride, each of the metal oxide, the metal nitride, or the metal-oxide-nitride is optionally doped with carbon. The method of claim 2, wherein the first surface comprises metallic silicon (Si), metallic germanium (Ge), or SiGe alloy, metallic silicon (Si), metallic germanium (Ge), or SiGe alloy Each of is optionally doped with phosphorus (P), arsenic (As), and/or boron (B), and the second surface includes _{silicon oxide (SiO x} ), silicon nitride (SiN), silicon oxide Each of silicon nitride (SiON), silicon oxide (SiO _x ), silicon nitride (SiN), and silicon oxide-nitride (SiON) is optionally doped with carbon. The method according to claim 1, wherein the PECVD process comprises co-flowing a metal precursor and a reducing co-reaction precursor into the processing chamber. The method according to claim 4, wherein the metal precursor includes a metal halide and the reducing co-reaction precursor includes hydrogen. The method of claim 1, wherein the PECVD treatment includes a direct plasma with a plasma power in the range of about 1 to less than about 700 mW/cm ^{2 and}

A substrate temperature of 500°C. The method according to claim 1, wherein a plasma power is provided for a period of about 0.0000001 to about 90 seconds every about 0.00001 to about 100 seconds. The method of claim 1, wherein the PECVD process includes a direct plasma at a frequency in the range of about 10 kHz to about 50 MHz. The method of claim 1, wherein the metal film is selectively deposited with a selectivity of at least about 10:1 relative to the second surface on the first surface. The method according to claim 5, wherein the metal halide comprises titanium chloride, zirconium chloride, or hafnium chloride, and the reducing co-reaction precursor comprises H ₂ . The method according to claim 5, wherein the first surface comprises metallic silicon (Si), metallic germanium (Ge), or SiGe alloy, metallic silicon (Si), metallic germanium (Ge), or SiGe alloy Each of is optionally doped with phosphorus (P), arsenic (As), and/or boron (B), and the second surface includes _{silicon oxide (SiO x} ), silicon nitride (SiN), silicon oxide - nitride (SiON), silicon oxide (SiO _x), silicon nitride (SiN), silicon oxide - nitride (SiON) each of carbon optionally doped. A method of depositing a metal film, the method comprising the following steps: positioning a substrate in a processing chamber, the substrate having a first surface and a second surface, the first surface being: metallic silicon (Si), Each of metallic germanium (Ge), or SiGe alloy, metallic silicon (Si), metallic germanium (Ge), or SiGe alloy is optionally doped with phosphorus (P), arsenic (As), and/or Boron (B), and the second surface is a metal oxide, a metal nitride, or a metal-oxide-nitride, the metal oxide, the metal nitride, or the metal-oxide-nitride Each of the are optionally doped with carbon; a metal precursor, hydrogen, and a carrier gas are flowed into the processing chamber, and the metal precursor includes a titanium halide, a zirconium halide, and/or a hafnium Halide; the metal precursor is energized by the application of a plasma power in the range of about 1 to less than about 700 mW/cm ^{2 and a frequency in the range of about 10kHz to about 50MHz} And hydrogen; and reacting the energized metal precursor with hydrogen to selectively deposit a metal film on the first surface with respect to the second surface with a selectivity of at least about 10:1, wherein the metal The film contains titanium (Ti), zirconium (Zr), or hafnium (Hf) in an amount greater than or equal to about 95 atomic percent. The method according to claim 12, wherein the frequency is about 13.56 MHz. The method according to claim 12, wherein a substrate temperature is

500°C. The method of claim 14, wherein the substrate temperature is in a range of about 300°C to about 440°C. The method according to claim 12, further comprising pulsing the plasma power. The method of claim 16, wherein the plasma power is provided for a period of about 0.0000001 to about 90 seconds every about 0.00001 to about 100 seconds.

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