Selective Deposition Method of Molybdenum

Abstract

This specification describes a method of selective deposition. This method includes depositing an oxide on a first portion of a substrate surface selected from the group consisting of a metal surface, a metal nitride surface, and a metal silicide surface. This method further includes selectively depositing a molybdenum film on a second portion of the substrate surface on which the oxide has not been deposited.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to a method for selectively depositing molybdenum on a metal surface or a metal nitride surface. Certain embodiments of the present disclosure are directed to a selective deposition method that utilizes lanthanum oxide for selective deposition in applications of patterned deposition and gap filling.

Background Art

[0002]

[0002] The semiconductor industry faces many challenges in pursuing device miniaturization, including the rapid scaling of nanoscale features. Such challenges include the manufacture of complex devices, which often use multiple lithography processes and etching processes. In addition, the semiconductor industry needs low-cost alternatives to expensive EUV for patterning complex architectures. Selective deposition is promising for reducing the cost of chip manufacturing while advancing device miniaturization. Simplifying the integration scheme may reduce costly lithography processes.

[0003]

[0003] Selective deposition of materials can be achieved in various ways. For example, some processes have inherent selectivity for a surface based on the chemical properties of the surface. Such processes are rare and are usually specific to the reactants used, the materials formed, and the substrate surface.

[0004]

[0004] Furthermore, as the dimensions of devices continue to shrink, the gaps / spaces between devices also shrink, making it difficult to physically separate the devices from each other. Filling high aspect ratio trenches / spaces / gaps between devices, which are often irregularly shaped, with a high-quality dielectric material is becoming increasingly difficult to implement using existing methods that include applying gap fill, hard mask, and spacers. Selective deposition methods typically involve depositing a mask material on a substrate and patterning the mask material to form a patterned mask. Then, after patterning the mask, regions of the substrate can be exposed through the patterned mask. To expose non-implanted regions of the substrate, the patterned mask is removed from the substrate, and material can be selectively deposited on selected regions of the substrate. However, these methods of utilizing a mask material, patterning the mask material, and removing the mask require multiple process steps in several process flows.

[0005]

[0005] There is a need for a new molybdenum deposition process that enhances the selectivity of depositing molybdenum on a particular oxide compared to metal surfaces that utilize fewer process steps than existing methods that involve deposition and removal of a mask material.

Summary of the Invention

[0006]

[0006] One or more embodiments of the present disclosure are directed to a method of selective deposition. The method includes depositing an oxide on a first portion of a substrate surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof, and selectively depositing a molybdenum film on a second portion of the substrate surface where the oxide has not been deposited.

[0007]

[0007] In some embodiments, a method of filling a gap in a substrate is provided. In one or more embodiments, the method of filling a gap in a substrate comprises depositing an oxide layer on sidewall surfaces of the gap, wherein the sidewall surfaces include surfaces selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof, and depositing molybdenum on a bottom surface of the gap where the oxide layer has not been deposited.

[0008]

[0008] To better understand the above-described features of the present disclosure, a more detailed description of the present disclosure, briefly summarized above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the present disclosure may admit other equally effective embodiments, and the accompanying drawings show only typical embodiments of the present disclosure and should not be regarded as limiting the scope of the present disclosure.

Brief Description of the Drawings

[0009]

Figure 1

[0009] An exemplary substrate during processing according to one or more embodiments of the present disclosure is shown.

Figure 2

[0010] An exemplary processing method according to one or more embodiments of the present disclosure is shown.

Figure 3A

[0011] An exemplary substrate having features is shown.

Figure 3B

[0012] A substrate having features shown in FIG. 3A with an oxide layer on the sidewalls is shown.

Figure 3C

[0013] A substrate having features shown in FIG. 3B with a molybdenum layer in the features is shown.

Modes for Carrying Out the Invention

[0010]

[0014] Before describing some exemplary embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of the configurations or process steps described in the following description. The present disclosure can have other embodiments and can be practiced or carried out in various ways.

[0011]

[0015] As used in this specification and the appended claims, the terms "substrate" and "wafer" are used interchangeably and both refer to the surface or a part of the surface on which the processing acts. Also, it will be understood by those skilled in the art that references to a substrate may, unless the context clearly indicates otherwise, refer only to a part of the substrate. In addition, references to deposition on a substrate may mean both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

[0012]

[0016] Furthermore, as used herein, "substrate" refers to any substrate on which film processing is performed during a manufacturing process or any material surface formed on a substrate. For example, substrate surfaces on which processing can be performed include 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, etc., and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. The substrate includes, but is not limited to, semiconductor wafers.

[0013]

[0017] The substrate can be exposed to a pretreatment process for polishing the substrate surface, etching, reducing, oxidizing, hydroxylation (or otherwise generating or grafting target chemical moieties to impart chemical functionality), annealing, and / or baking. In addition to direct film treatment on the surface of the substrate itself, in the present disclosure, any of the disclosed film treatment steps can also be performed on an underlying layer formed on the substrate, as will be disclosed in more detail below, and the term "substrate surface" is intended to include such an underlying layer as the context indicates. Thus, for example, when a film / layer or a partial film / layer is deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface. What a given substrate surface includes will depend on what films are deposited and the specific chemistry used.

[0014]

[0018] As used herein, the term "patterned substrate" refers to a substrate having a plurality of different material surfaces. In some embodiments, the patterned substrate includes a first surface and a second surface. In some embodiments, the first surface includes an oxide and the second surface includes a metal, a metal nitride, and / or a metal silicide.

[0015]

[0019] Terms such as "reactive gas", "process gas", "precursor", "reactant", etc. used in this specification and the appended claims are used interchangeably and mean a gas containing species that react with the substrate surface. For example, a first "reactive gas" may simply adsorb on the surface of the substrate and be available for further chemical reaction with a second reactive gas.

[0016]

[0020] Embodiments of the present disclosure provide a method of selective deposition using lanthanum oxide (La2O3).

[0017]

[0021] As used in this specification and the appended claims, terms such as "selectively deposit on the first surface from the second surface" mean that a first amount of a film or layer is deposited on the first surface and a second amount of a film or layer is deposited on the second surface, where the second amount of the film is less than the first amount of the film or no film is deposited on the second surface. The term "over" as used in this context does not mean that one surface is physically oriented on top of the other surface, but rather means the relationship of the thermodynamic or mechanical properties of the chemical reaction of one surface with respect to the other surface. For example, selectively depositing a molybdenum film on a metal surface rather than an oxide surface means that the molybdenum film is deposited on the metal surface and little or no molybdenum film is deposited on the oxide surface, or that the formation of the molybdenum film on the metal surface is thermodynamically or kinetically more favorable than the formation of the molybdenum film on the oxide surface.

[0018]

[0022] In some embodiments, "selectively" means that the target substance is formed on the target surface at a rate about 10 times, 15 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, or 50 times or more the rate of formation on the non-selected surface. In other words, the selectivity of the target substance surface with respect to the non-selected surface is about 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1 or more.

[0019]

[0023] According to one or more embodiments, the use of an oxide layer is employed for selective deposition. In this case, the oxide layer has a negligible effect on the target substrate material and is formed on the substrate material on which deposition should be avoided. The oxide layer can be used to deposit a film on the target substrate material while minimizing or preventing deposition on other substrate materials.

[0020]

[0024] Referring to FIG. 1, one or more embodiments of the present disclosure are directed to a processing method 100. The substrate 105 includes a surface that includes a first portion 111a and a second portion 112b. When an oxide layer 120 is deposited on the first portion 112a of the substrate 105, the second material 120 has an oxide surface 122. The second portion 112b includes the material of the substrate 105, and the first portion 112a of the substrate includes the oxide surface 122.

[0021]

[0025] In some embodiments, the substrate 105 and the second portion 112b of the substrate surface are selected from a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof. In one or more embodiments, the metal includes one or more of tungsten, titanium, aluminum, lanthanum, and molybdenum. In some embodiments, the metal nitride surface and the metal silicide surface include one or more of TiN, MoN, LaN, TiSiN, TaN, TaSiN, MoSi x , TaSi x , and WN. In a particular embodiment, the metal nitride surface includes TiN.

[0022]

[0026] The oxide according to one or more embodiments is selected from the group consisting of SiO2, Al2O3, ZrO2, HfO2, La2O3, and combinations thereof. In some embodiments, the oxide is deposited using a process selected from the group consisting of atomic layer deposition (ALD), chemical vapor deposition (CVD), pulsed chemical vapor deposition (pCVD), and physical vapor deposition (PVD). In a particular embodiment, the oxide surface includes lanthanum oxide (La2O3).

[0023]

[0027] Thus, referring to FIG. 2, according to one or more embodiments, method 200 includes depositing an oxide on a first portion of a substrate surface at step 210. What is shown at 220 is a second portion of the substrate surface that does not have an oxide surface. At step 230, molybdenum is deposited on the second portion of the substrate surface that does not have an oxide. Molybdenum according to one or more embodiments is deposited by PVD, CVD, pCVD, or ALD. Suitable molybdenum precursors include, but are not limited to, MoCl5, MoO2Cl2, MoOCl4, and MoF6.

[0024]

[0028] In some embodiments, the substrate includes features such as vias. Referring now to FIGS. 3A - C, embodiments are shown in which a gap 302 (or via) of substrate 300 is filled, such as by a bottom - up gap - filling process. FIG. 3A shows a substrate 300 having a top surface 310 and a gap 302 (or via) having a first side - wall surface 320, a second side - wall surface 321, and a bottom surface 330.

[0025]

[0029] In one or more embodiments of the method, after the oxide layer 120 is deposited, the method includes selectively depositing a molybdenum film 115 on a second portion 112b of the substrate surface where no oxide is deposited on top, as shown as the second surface 112b of the substrate in FIG. 1. When the oxide layer 120 is present, deposition on the oxide surface is suppressed or prevented, so that molybdenum is selectively deposited on the substrate 105.

[0026]

[0030] According to some embodiments, selectively depositing the molybdenum film 115 includes a pulsed chemical vapor deposition (pCVD) process or an atomic layer deposition (ALD) process.

[0027]

[0031] In one or more embodiments, a method of filling a gap 302 (or via) in a substrate 300 includes depositing an oxide on the sidewall surfaces of the gap 302. In the illustrated embodiment, the oxide layer 350 is deposited on the first sidewall surface 320 that defines the gap 302 (or via) and on the second sidewall surface 321 on the opposite side. The gap 302 further includes a bottom surface 330 on which the oxide layer 350 is not deposited. In FIG. 3C, a molybdenum film 340 is deposited on the bottom surface 330 to fill the gap 302 between the first sidewall surface 320 and the second sidewall surface 321 having the oxide film 350 on top. In one or more embodiments, the bottom surface includes a surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof.

[0028]

[0032] According to one or more embodiments, the metal includes one or more of tungsten, titanium, aluminum, lanthanum, and molybdenum. In some embodiments, the metal nitride surface and the metal silicide surface include one or more of TiN, MoN, LaN, TiSiN, TaN, TaSiN, MoSi x 、TaSi x 、and WN. In some embodiments, the oxide is selected from the group consisting of SiO2, Al2O3, ZrO2, HfO2, La2O3, and combinations thereof.

[0029]

[0033] In one or more embodiments, the oxide is deposited using a process selected from the group consisting of atomic layer deposition (ALD), chemical vapor deposition (CVD), pulsed chemical vapor deposition (pCVD), and physical vapor deposition (PVD). In some embodiments, selectively depositing the molybdenum film includes a pulsed chemical vapor deposition (pCVD) process. In some embodiments, depositing the molybdenum film includes an atomic layer deposition (ALD) process.

[0030]

[0034] In a particular embodiment, the bottom surface 330 includes titanium nitride and the oxide includes La2O3.

[0031]

[0035] In an embodiment where an ALD process is utilized to deposit molybdenum, there is a first pulse of a molybdenum precursor, a purge, a hydrogen (H2) pulse, and a purge of hydrogen (H2), after which this process is repeated until the desired layer thickness is obtained. In pulsed CVD (pCVD process), after flowing a molybdenum precursor and hydrogen (H2) gas together, the flow of the molybdenum precursor is stopped and only hydrogen (H2) gas is flowed for one cycle. This cycle is repeated until the desired film thickness is obtained.

[0032]

[0036] Exemplary non-limiting deposition temperatures for advantageously providing selective molybdenum deposition are in the range of 450 °C to 600 °C. Deposition pressures suitable for advantageously providing selective molybdenum deposition are in the range of 15 Torr to 50 Torr. Hydrogen flow rates suitable for advantageously providing selective molybdenum deposition are in the range of 5 slm to 30 slm. In the pCVD process, the molybdenum precursor is pulsed over a time range of 0.1 second to 5 seconds.

[0033]

[0037] As used herein, "atomic layer deposition" or "cyclic deposition" refers to sequentially exposing two or more reactive compounds to deposit a layer of material on a substrate surface. The substrate or a portion of the substrate is separately exposed to two or more reactive compounds introduced into the reaction zone of the processing chamber. In a time-domain ALD process, each exposure to a reactive compound is separated by a time delay to allow each compound to adhere and / or react on the substrate surface and then be purged from the processing chamber. These reactive compounds are said to be sequentially exposed to the substrate. In a spatial ALD process, different portions of the substrate surface, or materials on the substrate surface, are simultaneously exposed to two or more reactive compounds, and no given point on the substrate is substantially simultaneously exposed to a plurality of reactive compounds. As used herein and in the appended claims, the term "substantially" as used in this context means, as understood by one of ordinary skill in the art, that a small portion of the substrate may be exposed to a plurality of reactive gases simultaneously due to diffusion, and it is not intended that such simultaneous exposure occur.

[0034]

[0038] In one aspect of the time-domain ALD process, a first reactive gas (i.e., a first precursor or compound A) is pulsed into the reaction zone, followed by a first time delay. Next, a second precursor or compound B is pulsed into the reaction zone, followed by a second time delay. During each time delay, a purge gas (such as argon) is introduced into the processing chamber to purge the reaction zone or otherwise remove any remaining reactive compound or reaction by-products from the reaction zone. Alternatively, the purge gas may flow continuously throughout the deposition process such that only the purge gas flows during the time delay between pulses of the reactive compound. The reactive compounds are pulsed alternately until a desired film or film thickness is formed on the substrate surface. In any scenario, the ALD process that pulses compound A, the purge gas, compound B, and the purge gas is one cycle. The cycle can start with either compound A or compound B and continues through each sequence of the cycle until a film with a predetermined thickness is achieved.

[0035]

[0039] In an embodiment of the spatial ALD process, a first reactive gas and a second reactive gas (e.g., nitrogen gas) are supplied to the reaction zone simultaneously but are separated by an inert gas curtain and / or a vacuum curtain. The substrate is moved relative to the gas supply device such that any given point on the substrate is exposed to the first reactive gas and the second reactive gas.

[0036]

[0040] In some embodiments, the improvement in selectivity is evident compared to a process that uses an oxide to cover a portion of the substrate. In some embodiments, the deposition rate of the film on a substrate that does not have an oxide thereon is at least 5% greater, at least 10% greater, at least 20% greater, at least 30% greater, at least 40% greater, or at least 50% greater than the deposition rate on a substrate that has been cleaned with a hydrogen plasma.

[0037]

[0041] Throughout this specification, references to "one embodiment", "a particular embodiment", "one or more embodiments", or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one or more embodiments", "in a particular embodiment", "in one embodiment", or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0038]

[0042] The disclosure herein has been described with reference to particular embodiments, but those skilled in the art will understand that the described embodiments are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatuses of the present disclosure without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure can include modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

1. A method of selective deposition, comprising: depositing an oxide on a first portion of a substrate surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof; selectively depositing a molybdenum film on a second portion of the substrate surface where the oxide is not deposited .

2. The method according to claim 1, wherein the metal comprises one or more of tungsten, titanium, aluminum, lanthanum, and molybdenum.

3. The metal nitride surface and the metal silicide surface are one or more of TiN, MoN, LaN, TiSiN, TaN, TaSiN, MoSi ｘ , TaSi ｘ , and WN, and the method according to claim 1.

4. The oxide is SiO ２ , Al ２ O ３ , ZrO ２ , HfO ２ , La ２ O ３ and a combination thereof, and the method according to claim 1, which is selected from the group consisting of these combinations.

5. The method according to claim 4, wherein the oxide is deposited using a process selected from the group consisting of atomic layer deposition (ALD), chemical vapor deposition (CVD), pulsed chemical vapor deposition (pCVD), and physical vapor deposition (PVD).

6. The method according to claim 1, wherein selectively depositing the molybdenum film comprises a pulsed chemical vapor deposition (pCVD) process.

7. The method according to claim 1, wherein selectively depositing the molybdenum film comprises an atomic layer deposition (ALD) process.

8. The method according to claim 1, wherein the first surface comprises titanium nitride.

9. The oxide is La ２ O ３ The method according to claim 8, comprising 。

10. The method according to claim 1, wherein the substrate surface comprises features.

11. The method according to claim 10, wherein the features comprise vias.

12. A method of filling a gap in a substrate, comprising: depositing an oxide layer on a sidewall surface of the gap, wherein the sidewall surface comprises a surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof; depositing molybdenum on a bottom surface of the gap where the oxide layer is not deposited .

13. The method according to claim 12, wherein the metal comprises one or more of tungsten, titanium, aluminum, lanthanum, and molybdenum.

14. The metal nitride surface and the metal silicide surface are one or more of TiN, MoN, LaN, TiSiN, TaN, TaSiN, MoSi ｘ , TaSi ｘ , and WN, and the method according to claim 12.

15. The oxide is SiO ２ , Al ２ O ３ , ZrO ２ , HfO ２ , La ２ O ３ and a combination thereof, and the method according to claim 12, which is selected from the group consisting of these combinations.

16. The method according to claim 15, wherein the oxide is deposited using a process selected from the group consisting of atomic layer deposition (ALD), chemical vapor deposition (CVD), pulsed chemical vapor deposition (pCVD), and physical vapor deposition (PVD).

17. The method according to claim 12, wherein selectively depositing the molybdenum film comprises a pulsed chemical vapor deposition (pCVD) process.

18. The method according to claim 12, wherein selectively depositing the molybdenum film includes an atomic layer deposition (ALD) process. **Claim 19** The method according to claim 12, wherein the bottom surface includes titanium nitride. **Claim 20** The oxide is La ２ O ３ comprising the method according to claim 19 。

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