Method for selective deposition of molybdenum

Abstract

Methods for selective deposition are described herein. 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, and a metal silicide surface. The method further includes selectively depositing a molybdenum film on a second portion of the surface of the substrate, the second portion having no oxide deposited thereon.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to methods for selectively depositing molybdenum on metal surfaces or metal nitride surfaces. Specific embodiments of the present disclosure are directed to selective deposition methods utilizing lanthanum oxide for selective deposition in patterned deposition and gap fill applications. Background Art

[0002] The semiconductor industry faces many challenges in the quest for device miniaturization including rapid scaling of nanometer-scale features. Such challenges include the fabrication of complex devices that typically use multiple lithography steps and etching processes. In addition, the semiconductor industry needs a low-cost alternative to the high-cost EUV for patterning complex architectures. In order to maintain the progress of device miniaturization and keep chip manufacturing costs down, selective deposition has shown promising success. It has the potential to remove expensive lithography steps by simplifying integration schemes.

[0003] Selective deposition of materials can be accomplished in a variety of ways. For example, some processes may have inherent selectivity for surfaces based on their surface chemistry. These processes are rare and are often specific to the reactants used, the materials formed, and the substrate surface.

[0004] In addition, as the size of devices continues to shrink, the gaps / spaces between devices also shrink, increasing the difficulty of physically isolating devices from each other. Filling high aspect ratio trenches / spaces / gaps between devices of generally irregular shapes with high quality dielectric materials becomes an increasing challenge for the implementation of current methods including gap filling, hard mask and spacer applications. Selective deposition methods typically include depositing mask materials on substrates, and patterning mask materials to form patterned masks. After patterning of the mask, multiple areas of the substrate can then be exposed through the patterned mask. The patterned mask can be removed from the substrate to expose the unimplanted areas of the substrate, and the material can be selectively deposited on the selected areas of the substrate. However, these methods utilizing mask materials, patterning mask materials, and removing masks require multiple process steps in several process flows.

[0005] There is a need for new molybdenum deposition processes that increase the selectivity of molybdenum deposition on specific oxides compared to metal surfaces, which utilize fewer process steps than current methods that utilize deposition and removal of mask materials. Summary of the invention

[0006] One or more embodiments of the present invention relate to a method of selective deposition. The method comprises depositing an oxide on a first portion of a substrate surface, the substrate surface being 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, the second portion of the substrate surface being free of the oxide deposited on the second portion of the substrate surface.

[0007] In some embodiments, a method of filling a gap in a substrate. In one or more embodiments, the method of filling a gap in a substrate comprises depositing an oxide layer on a sidewall surface of the gap, the sidewall surface comprising a surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and a combination of the foregoing; and depositing molybdenum on a bottom surface of the gap, the bottom surface of the gap not having the oxide layer deposited on the bottom surface of the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more particular description of the present disclosure, briefly summarized above, may be obtained by reference to embodiments so that the manner in which the above-mentioned features of the present disclosure are understood in detail, some of which are illustrated in the accompanying drawings. It will be noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of the scope of the present disclosure, as the present disclosure may admit to other equally effective embodiments.

[0009] Figure 1 illustrates an example substrate during processing according to one or more embodiments of the present disclosure;

[0010] Figure 2 illustrates an example processing method according to one or more embodiments of the present disclosure;

[0011] Figure 3A An example substrate having features is shown;

[0012] Figure 3B Diagram Figure 3A A substrate having the features shown in , the substrate having an oxide layer on the sidewalls; and

[0013] Figure 3C Diagram Figure 3B A substrate having features is shown in FIG. , the substrate having a molybdenum layer in the features. DETAILED DESCRIPTION

[0014] Before describing several exemplary embodiments of the present disclosure, it will be understood that the present disclosure is not limited to the details of the architecture or process steps described in the following specification. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0015] As used in this specification and the appended claims, the terms "substrate" and "wafer" are used interchangeably, and both refer to a surface or portion of a surface on which a process acts. Unless the context clearly indicates otherwise, those skilled in the art will also understand that reference to a substrate may also refer to only a portion of a substrate. In addition, reference to depositing on a substrate may mean both a bare substrate and a substrate having one or more films or features deposited or formed on the substrate.

[0016] In addition, as used herein, "substrate" refers to any substrate or a material surface formed on a substrate on which a film process is performed during a manufacturing process. For example, substrate surfaces on which processes may 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, and any other material such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, without limitation, semiconductor wafers.

[0017] The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate (or generate or graft a target chemical moiety to impart chemical functionality), anneal, and / or bake the substrate surface. In addition to film treatments directly on the surface of the substrate itself, in the present disclosure, any of the film treatment steps disclosed may also be performed on an underlayer formed on the substrate, as described in more detail below, and the term "substrate surface" is intended to include such underlayers as indicated by the context. Thus, for example, where a film / layer or portion of a film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface. What a given substrate surface contains will depend on what film is to be deposited and the specific chemistry used.

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

[0019] As used in this specification and the appended claims, the terms "reactant gas," "process gas," "precursor," "reactant," and the like are used interchangeably to mean a gas that includes species that react with a substrate surface. For example, a first "reactant gas" may simply adsorb onto the surface of a substrate and be available for further chemical reaction with a second reactant gas.

[0020] Embodiments of the present disclosure provide methods utilizing selective deposition of lanthanum oxide (La2O3).

[0021] As used in this specification and the appended claims, the phrase "selectively depositing on a first surface over a second surface" and similar phrases means that a first amount of film or layer is deposited on the first surface and a second amount of film or layer is deposited on the second surface, wherein the second amount of film is less than the first amount of film, or no film is deposited on the second surface. The term "over" used in this manner does not imply a physical orientation of one surface on top of another surface, but rather a relationship to the thermodynamic or kinetic properties of chemical reactions of one surface relative to the other surface. For example, selectively depositing a molybdenum film on a metal surface over an oxide surface means that the molybdenum film is deposited on the metal surface, while less or no molybdenum film is deposited on the oxide surface; or that the formation of a molybdenum film on the metal surface is thermodynamically or kinetically favored relative to the formation of a molybdenum film on the oxide surface.

[0022] In some embodiments, "selectivity" means that the subject material is formed on the target surface at a rate that is greater than or equal to about 10, 15, 20, 25, 30, 35, 40, 45, or 50 times the rate of formation on the non-selected surface. In other words, the selectivity for the target material surface relative to the non-selected surface is greater than or equal to about 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, or 50:1.

[0023] According to one or more embodiments, selective deposition employs the use of an oxide layer, wherein the oxide layer is formed on a substrate material on which deposition is to be avoided with negligible effect on a target substrate material. A film can be deposited on the target substrate material, while deposition on other substrate materials is minimized or prevented by the oxide layer.

[0024] Reference Figure 1 , one or more embodiments of the present disclosure relate to a processing method 100. A substrate 105 includes a surface, the surface including 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.

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

[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 specific embodiment, the oxide surface comprises lanthanum oxide (La2O3).

[0027] Therefore, refer to Figure 2 According to one or more embodiments, method 200 includes depositing an oxide on a first portion of a substrate surface at operation 210. Shown at 220 is a second portion of the substrate surface without an oxide surface. At operation 230, molybdenum is deposited on a second portion of the substrate surface, the second portion without an oxide on the second portion. 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.

[0028] In some embodiments, the substrate includes features, such as vias. Figure 3A-3C , shows an embodiment in which a gap 302 (or via) in a substrate 300 is shown as being filled, such as in a bottom-up gap fill process. Figure 3A The substrate 300 is shown. The substrate 300 has a top surface 310 and a gap 302 (or a via hole). The gap 302 (or a via hole) has a first sidewall surface 320 , a second sidewall surface 321 and a bottom surface 330 .

[0029] In one or more embodiments of the method, after the oxide layer 120 has been deposited, the method includes depositing a second portion 112b of the substrate surface (the second portion not having an oxide deposited thereon) (e.g. Figure 1The molybdenum film 115 is selectively deposited on the second surface 112b) of the substrate shown in FIG. The presence of the oxide layer 120 layer inhibits or prevents deposition at the oxide surface, and thus molybdenum is selectively deposited on the substrate 105.

[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).

[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 embodiment shown, an oxide layer 350 is deposited on a first sidewall surface 320 and an opposed second sidewall surface 321 defining the gap 302 (or via). The gap 302 further includes a bottom surface 330 that does not have an oxide layer 350 deposited on the bottom surface 330. Figure 3C , a molybdenum film 340 is deposited on the bottom surface 330, filling the gap 302 between the first sidewall surface 320 and the second sidewall surface 321, which have an oxide layer 350 on the first sidewall surface 320 and the second sidewall surface 321. 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.

[0032] According to one or more embodiments, the metal comprises one or more of tungsten, titanium, aluminum, lanthanum, and molybdenum. In some embodiments, the metal nitride and metal silicide surfaces comprise 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.

[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 comprises a pulsed chemical vapor deposition (pCVD) process. In some embodiments, depositing the molybdenum film comprises an atomic layer deposition (ALD) process).

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

[0035] In an embodiment utilizing an ALD process to deposit molybdenum, there is a first pulse of a molybdenum precursor, a purge, a hydrogen (H2) pulse, a purge of hydrogen (H2), and then this process is repeated until the desired layer thickness is obtained. In a pulsed CVD (pCVD) process, the molybdenum precursor flows with hydrogen (H2) gas, and then the molybdenum precursor flow is terminated and only hydrogen (H2) gas flows for a single cycle. This cycle is repeated until the desired film thickness is achieved.

[0036] Example non-limiting deposition temperatures for advantageously providing selective molybdenum deposition are in the range of 450°C to 600°C. Suitable deposition pressures for advantageously providing selective molybdenum deposition are in the range of from 15 Torr to 50 Torr. Suitable hydrogen flow rates for advantageously providing selective molybdenum deposition are in the range of from 5 slm to 30 slm. For the pCVD process, the molybdenum precursor is pulsed for a time in the range of 0.1 seconds to 5 seconds.

[0037] As used herein, "atomic layer deposition" or "cyclic deposition" refers to the sequential exposure of two or more reactive compounds for depositing a layer of material on a substrate surface. The substrate or portions of the substrate surface are separately exposed to two or more reactive compounds introduced into a reaction zone of a processing chamber. In a time-domain ALD process, the exposure to each 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 exposed to the substrate sequentially. 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, so that any given point on the substrate is not substantially simultaneously exposed to more than one reactive compound. When used in this specification and the appended claims, as will be understood by those skilled in the art, the term "substantially" used in this manner means that there is a possibility that a small portion of the substrate is simultaneously exposed to multiple reactive gases due to diffusion, and this simultaneous exposure is not intentional.

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

[0039] In an embodiment of a spatial ALD process, a first reactant gas and a second reactant gas (e.g., nitrogen) are delivered to the reaction region simultaneously but separated by an inert gas curtain and / or a vacuum curtain. The substrate moves relative to the gas delivery apparatus so that any given point on the substrate is exposed to the first reactant gas and the second reactant gas.

[0040] In some embodiments, the selectivity improvement over using an oxide to cover a portion of a substrate is significant. In some embodiments, the deposition rate of the film on a substrate without an oxide on the substrate is at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, or at least 50% greater than the deposition rate on a substrate cleaned with a hydrogen plasma.

[0041] References throughout this specification to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" mean that the particular features, structures, materials, or characteristics described with respect to that embodiment are included in at least one embodiment of the present invention. Thus, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing in various places throughout this specification do not necessarily refer to the same embodiment of the present disclosure. Furthermore, in one or more embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner.

[0042] Although the disclosure herein is described with reference to specific embodiments, it will be appreciated by those skilled in the art that the described embodiments are merely illustrative of the principles and applications of the present invention. It is apparent to those skilled in the art that various modifications and variations may be made to the methods and apparatus of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure may include modifications and variations that fall within the scope of the appended claims and their equivalents.

Claims

1. A method for selective deposition, the method comprising the following steps: depositing an oxide on a first portion of a substrate surface, the substrate surface selected from the group consisting of a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof; and A molybdenum film is selectively deposited on a second portion of the substrate surface, the second portion of the substrate surface being free of the oxide deposited on the second portion of the substrate surface.

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

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

4. The method of claim 1, wherein the oxide is selected from the group consisting of SiO2, Al2O3, ZrO2, HfO2, La2O3, and combinations thereof.

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

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

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

9. The method of claim 8, wherein the oxide comprises La2O3.

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

11. The method of claim 10, wherein the feature comprises a via 12. A method for filling a gap in a substrate, the method comprising the steps of: depositing an oxide layer on a sidewall surface of the gap, the sidewall surface comprising a surface selected from the group consisting of: a metal surface, a metal nitride surface, a metal silicide surface, and combinations thereof; and Molybdenum is deposited on a bottom surface of the gap, the bottom surface of the gap being free of the oxide layer deposited on the bottom surface of the gap.

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

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

15. The method of claim 12, wherein the oxide is selected from the group consisting of SiO2, Al2O3, ZrO2, HfO2, La2O3, and combinations thereof.

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

18. The method of claim 12, wherein selectively depositing the molybdenum film comprises an atomic layer deposition (ALD) process).

19. The method of claim 12, wherein the bottom surface comprises titanium nitride.

20. The method of claim 19, wherein the oxide comprises La2O3.

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