Surface treatment for selective deposition

Abstract

Methods for surface pretreatment during selective deposition are disclosed. One or more embodiments of the present disclosure provide surface pretreatment that facilitates the removal of a barrier layer. Some embodiments of the present disclosure include a surface pretreatment comprising exposing a substrate having a first surface and a second surface to modify the first surface, depositing a barrier layer on the modified first surface, selectively depositing a film on the second surface relative to the barrier layer, and removing the barrier layer.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to surface treatments for selective deposition methods on non-metallic surfaces. More specifically, some embodiments of the present disclosure relate to methods for selective deposition on non-metallic surfaces using surface treatments and barrier compounds comprising SAMs and / or unsaturated hydrocarbons. The surface treatments facilitate removal of the barrier compounds prior to subsequent deposition. Background Art

[0002] Selective deposition processes are gaining significant traction, primarily due to demand for patterning applications in semiconductors. Traditionally, patterning in the microelectronics industry has been accomplished using various lithography techniques and etching processes. However, as lithography becomes exponentially more complex and expensive, using selective deposition to deposit features is becoming increasingly attractive. Another potential application for selective deposition is gapfill. In gapfill, the filler film is selectively grown from the bottom of the trench toward the top. Selective deposition can also be used for other applications, such as selective sidewall deposition of films grown on the sides of fins. This enables the deposition of sidewall spacers without the need for complex patterning steps.

[0003] In middle-of-line (MOL) and back-end-of-line (BEOL) structures, barrier films are often used between metal lines and dielectric layers to prevent diffusion and other adverse interactions between the dielectric layer and the metal lines. However, due to the high resistivity of barrier films, barrier films often contribute the most to via resistance.

[0004] Past approaches have focused on reducing the thickness of barrier films or finding barrier films with lower resistivity to lower via resistance. However, the increased via resistance due to barrier films remains a problem, especially in smaller CD features when the volume percentage of the via formed by barrier films on the sidewalls increases.

[0005] Another approach is to block or reduce the thickness of the barrier film on the metal surface at the bottom of the via, while maintaining the thickness on the dielectric surface at the sidewalls. Because the barrier properties of a barrier film are directly related to the film thickness between the metal and the dielectric, this approach can leave the barrier film intact, but the reduced thickness on the metal surface increases the via resistance. These processes are called selective deposition processes.

[0006] The current solution is to use self-assembled monolayers (SAMs) to inhibit the nucleation and growth of barrier films on metal surfaces. To prevent deposition, a strong interaction between the SAM and the metal surface is preferred, but this interaction may become an obstacle to removing the SAM in subsequent deposition processes.

[0007] Therefore, a surface pretreatment method that is beneficial for removing SAM is needed. Summary of the Invention

[0008] One or more embodiments of the present disclosure relate to a selective deposition method comprising exposing a substrate comprising a first material having a first surface and a second material having a second surface to a surface pretreatment to modify the first surface and form a modified first surface. The substrate is exposed to a barrier compound to selectively form a barrier layer on the modified first surface. A first film is selectively deposited on the second surface relative to the barrier layer. The barrier layer is removed from the first material. The surface pretreatment facilitates removal of the barrier layer from the first surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to be able to understand in detail some of the features of the present disclosure, a more particular description of the present disclosure, briefly summarized above, may be obtained by reference to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the drawings illustrate only some exemplary embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure, as the present disclosure may admit to other equally effective embodiments.

[0010] Figure 1 shows a cross-sectional view of an exemplary substrate during processing according to one or more embodiments of the present disclosure;

[0011] Figure 2 illustrating a cross-sectional view of an exemplary substrate during processing according to one or more embodiments of the present disclosure; and

[0012] Figure 3 is a schematic cross-sectional view of a substrate during selective deposition according to one or more embodiments of the present disclosure; and

[0013] Figure 4 An exemplary clustering tool according to one or more implementations of the present disclosure is shown. DETAILED DESCRIPTION

[0014] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or processing steps set forth in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0015] As used in this specification and the appended claims, the term "substrate" refers to a surface or portion of a surface on which a process is performed. Those skilled in the art will also understand that reference to a substrate may also refer to only a portion of a substrate, unless the context clearly indicates otherwise. Furthermore, reference to depositing on a substrate may refer to both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

[0016] As used herein, "substrate" refers to any substrate or material surface formed on a substrate on which film processing is performed during the manufacturing process. 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, amorphous silicon, 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. Substrates include, but are not limited to, semiconductor wafers. The substrate can be exposed to pretreatment treatments to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam cure and / or bake the substrate surface. In addition to performing film processing directly on the surface of the substrate itself, in the present disclosure, any disclosed film processing steps can also be performed on the bottom layer formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is intended to include such bottom layers as indicated by the context. Thus, for example, when a film / layer or portion of a film / layer has been deposited onto the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0017] As used in this specification and the appended claims, the terms "reactive gas," "precursor," "reactant," and similar terms are used interchangeably to refer to a gas that includes a species that reacts with a substrate surface. For example, a first "reactive gas" may simply adsorb onto a substrate surface and be available for further chemical reaction with a second reactive gas.

[0018] For decades, the semiconductor community has attempted to improve integrated circuit (IC) processing by replacing lithography steps with alternatives that translate into lower costs, shorter processing times, and smaller feature sizes. Many of these alternatives fall under the umbrella term "selective deposition." Generally speaking, selective deposition refers to a process in which the net deposition rate on a target substrate material is higher relative to other substrate materials, thereby achieving a desired film thickness on the target substrate material while exhibiting negligible deposition on other substrate materials (where "negligible" is defined by process constraints).

[0019] Selective deposition of materials can be accomplished in a variety of ways. Chemical precursors can selectively react with one surface relative to another surface (metal or dielectric). Processing parameters such as pressure, substrate temperature, precursor partial pressure and / or gas flow can be adjusted to adjust the chemical kinetics of a specific surface reaction. Another possible approach involves surface pretreatment, which can be used to activate or deactivate the surface of interest to the introduced thin film deposition precursor. Typically, selective deposition refers to depositing a film on a metal surface. Reverse selective deposition processes deposit films on dielectric surfaces rather than metal surfaces.

[0020] One strategy for achieving selective deposition is to use a barrier layer. Ideally, this strategy involves (1) forming a barrier layer on a substrate material where deposition on the barrier layer is avoided with negligible effect on the target substrate material, (2) depositing on the target substrate material (where deposition on other substrate materials is “blocked” by the barrier layer), and (3) removing the barrier layer without a net adverse effect on the deposited film.

[0021] One or more embodiments of the present disclosure relate to surface treatment methods that facilitate the removal of barrier layers. In some embodiments, the barrier layer is used in a selective deposition scheme. In some embodiments, the selective deposition scheme deposits the barrier layer within a substrate feature.

[0022] As used in this specification and the appended claims, the phrases "surface of a metallic material" or "surface of a non-metallic material" refer to the surface of a metallic or non-metallic material, respectively. For the purposes of this disclosure, a non-metallic material is any material that exhibits the properties of a poor conductor or a good insulator. Conversely, a metallic material is any material that exhibits the properties of a good conductor or a poor insulator. Non-metallic materials may include metal atoms (e.g., tantalum nitride, titanium nitride), but still fall within the scope of non-metallic materials. In some embodiments, the terms "conductive material" and "insulating material" are used in place of metallic material and non-metallic material, respectively.

[0023] As used in this specification and the appended claims, the term "selectively deposited on a first surface as compared to a second surface" or similar expressions means that a first amount or thickness is deposited on the first surface and a second amount or thickness is deposited on the second surface, wherein the second amount or thickness is less than the first amount or thickness, or in some embodiments, no amount is deposited on the second surface.

[0024] As used in this context, the term "over" does not mean the physical orientation of one surface on top of another surface, but rather the relationship of the thermodynamic or kinetic properties of the chemical reaction of one surface relative to the other surface. For example, selectively depositing a cobalt film on a copper surface as compared to a dielectric surface means that the cobalt film is deposited on the copper surface, while less or no cobalt film is deposited on the dielectric surface; or that forming a cobalt film on the copper surface is thermodynamically or kinetically more favorable than forming a cobalt film on the dielectric surface.

[0025] In some embodiments, "selectively" means that the subject material forms on the selected surface at a rate greater than or equal to about 2x, 3x, 4x, 5x, 7x, 10x, 15x, 20x, 25x, 30x, 35x, 40x, 45x, or 50x the rate of formation on the non-selected surface. In other words, the selectivity of the treatment of the selected surface relative to the non-selected surface is greater than or equal to about 2:1, 3:1, 4:1, 5:1, 7:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, or 50:1.

[0026] One or more embodiments of the present disclosure relate to methods for selectively forming a barrier layer on a first material surface of a substrate compared to a second material surface. In some embodiments, the substrate comprises a metallic material (conductive material) and a non-metallic material (insulating material). In some embodiments, the metallic material surface is referred to as the first material surface and the non-metallic material surface is referred to as the second material surface. In some embodiments, the designations of the first material surface and the second material surface are swapped.

[0027] The metal material of the substrate can be any suitable metal material. In some embodiments, the metal material of the present invention is a conductive material. Suitable metal materials include, but are not limited to, metals, conductive metal nitrides, conductive metal oxides, metal alloys, silicon, combinations thereof, and other conductive materials.

[0028] In some embodiments, the metallic material comprises or consists essentially of one or more of chromium, manganese, iron, copper, nickel, cobalt, tungsten, ruthenium, molybdenum, tantalum, or titanium. In some embodiments, the metallic material comprises or consists essentially of copper, cobalt, ruthenium, tungsten, or molybdenum. In some embodiments, the metallic material comprises or consists essentially of silicon. As used in this specification and the appended claims, the term "consisting essentially of" means that a material is greater than or equal to about 95%, 98%, or 99% of the material on an atomic basis.

[0029] As used in this specification and the appended claims, the term "oxide" or similar terms refers to a material comprising the specified metal element and oxygen. The term should not be interpreted as implying a specific ratio (stoichiometric or non-stoichiometric) of the elements.

[0030] The non-metallic material of the substrate can be any suitable material. In some embodiments, the non-metallic material of the present invention is a dielectric material. Suitable non-metallic materials include, but are not limited to, silicon oxide (e.g., SiO2), silicon nitride, silicon carbide, and combinations thereof (e.g., SiCON). Suitable non-metallic materials also include aluminum oxide, aluminum nitride, and low-k dielectric materials. In some embodiments, the non-metallic material comprises or consists essentially of silicon dioxide (SiO2). In some embodiments, the non-metallic material comprises or consists essentially of silicon nitride.

[0031] refer to Figure 1 , exemplary method 100 begins with substrate 105, which includes a first material 110 having a first surface 112 and a second material 120 having a second surface 122. Furthermore, substrate 105 has a substrate surface including first surface 112 and second surface 122. As described above, in some embodiments, first material 110 includes a conductive material and second material 120 includes an insulating material.

[0032] At operation 150, the substrate surface is exposed to a surface pretreatment to modify at least the first surface 112 and form a modified first surface 115. As used herein, the phrase "substrate surface is exposed" refers to the entire substrate, including the various materials and layers on the substrate (particularly their exposed surfaces), being exposed to the treatment or condition. Without being bound by theory, the surface pretreatment facilitates the subsequent removal of the barrier layer deposited at operation 160.

[0033] The surface pretreatment can be any surface modification that facilitates removal of the barrier layer without significantly adversely affecting the barrier layer's ability to prevent or minimize deposition on the first material. In some embodiments, the surface pretreatment comprises exposing the first surface to a nitrogen-containing reactant. In some embodiments, the nitrogen-containing reactant is exposed to the first surface as a plasma. In some embodiments, the nitrogen-containing reactant is exposed to the first surface in the absence of a plasma (e.g., thermal exposure). In some embodiments, the nitrogen-containing reactant comprises or consists essentially of one or more of nitrogen (N2), ammonia (NH3), nitrous oxide (N2O), nitrogen dioxide (NO2), hydrazine (N2H4), or derivatives thereof.

[0034] Without being bound by theory, it is believed that exposure to the nitrogen-containing reactant modifies the first surface by chemisorbing nitrogen atoms to at least a portion of the first surface. The nitrogen atoms on the surface do not adversely affect the ability of the barrier compound to bind to the first surface and inhibit deposition on the first surface, but they do facilitate removal of the barrier layer by intercalating nitrogen atoms between at least some molecules of the barrier compound and the first surface, thereby reducing the average bond energy between the barrier compound and the first surface.

[0035] At operation 160, the substrate 105 is exposed to a barrier compound to selectively form a barrier layer 130 on the modified first surface 115 as compared to the second surface 122. In some embodiments, the surface of the barrier layer is described as a blocked first surface 132. Alternatively, the barrier layer can be referred to as a passivation layer and the blocked first surface as a passivated first surface.

[0036] The barrier layer 130 is shown in the figure as a series of parallel wavy lines; however, those skilled in the art will recognize that this is merely a general representation and does not imply any particular morphology, density, or structure of the barrier layer 130 .

[0037] The barrier compound can be any compound capable of selectively forming a barrier layer 130 on the modified first surface 115 as compared to the second surface 122. In some embodiments, the barrier compound comprises a barrier molecule having the general formula AL, where A is a reactive head group and L is a carbonaceous tail group. In some embodiments, the barrier molecule comprises or consists essentially of n-octadecyltris(dimethylamino)silane.

[0038] As used in this manner, a “head group” is a chemical moiety that is associated with the modified first surface 115 and a “tail group” is a chemical moiety that extends away from the modified first surface 115 .

[0039] In some embodiments, the first material 110 comprises an insulating material and A is selected from (R2N)3Si-, X3Si-, and (RO)3Si-, wherein each R is independently selected from C1-C6 alkyl, C4-C8 cycloalkyl, and C4-C8 aryl, and each X is independently selected from halogen. In some embodiments, the first material 110 comprises a conductive material and A is selected from the group consisting of (HO)2OP-, HS-, and H3Si-.

[0040] Some of the reactive head groups listed above contain more than one reactive moiety in a single reactive head group connected to a tail group L (e.g., H3Si- can bond to the surface up to 3 times). In some embodiments, A is selected from a reactive group that is less than the number of reactive moieties listed above and A is connected to more than one tail group L. In these embodiments, the tail groups can be the same or different.

[0041] In some embodiments, L is -(CH2) nCH3 and n is an integer from 3 to 25. In some embodiments, the tail group L comprises less than 18 carbon atoms. In some embodiments, the tail group comprises less than 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, or 5 carbon atoms. In some embodiments, L comprises one or more reactive moieties to form a reactive tail group.

[0042] In some embodiments, the tail groups associate with each other via relatively slow van der Waals interactions. In some embodiments, the tail groups can be the same or different, thereby forming a homogeneous or heterogeneous SAM. In some embodiments, the barrier compound comprises at least two different barrier molecules, thereby forming a heterogeneous SAM.

[0043] The barrier compound can be delivered to the substrate as a single compound or as a sequential exposure of multiple compounds to form the barrier layer 130. In some embodiments, the modified first surface 115 is exposed to a single compound that assembles on the surface in an ordered or semi-ordered manner.

[0044] In some embodiments, the conditions for delivering the barrier compound to the substrate are controlled. In some embodiments, the conditions are controlled to maximize SAM uniformity across the substrate surface. In some embodiments, the pressure during delivery of the barrier compound is in the range of 15 to 50 Torr. In some embodiments, the temperature of the substrate is maintained in the range of 150° C. to 400° C.

[0045] In some embodiments, the barrier compound comprises an unsaturated hydrocarbon. Without being bound by theory, it is believed that the d-orbitals of the metallic material begin to align with the sp 2 orbitals share electrons. Thus, in some embodiments, the unsaturated hydrocarbon comprises at least one compound having at least one double bond between two carbon atoms. In some embodiments, the unsaturated hydrocarbon comprises at least one compound having at least one triple bond between two carbon atoms. In other words, in some embodiments, the unsaturated hydrocarbon comprises at least one compound having the general formula R'=R" or R'≡R". In some embodiments, the unsaturated hydrocarbon compound comprises only one unsaturated bond. Without being bound by theory, it is believed that multiple unsaturated bonds increase the likelihood of polymerization and increase the difficulty of removing the barrier layer without damaging the surrounding substrate material.

[0046] Furthermore, without being bound by theory, it is believed that the unsaturated hydrocarbon (barrier layer 130 ) inhibits one or more nucleation or growth rates of subsequent films on the modified first surface 115 .

[0047] In some embodiments, R' and R" are the same. In some embodiments, R' and R" are independent C2-C6 groups. As used in this regard, a "C2-C6 group" contains 2-6 carbon atoms. In some embodiments, R' and R" contain only carbon and hydrogen atoms. In some embodiments, R' and R" do not contain any surface reactive moieties. In some embodiments, the compound of unsaturated hydrocarbons does not contain an unsaturated bond with a terminal carbon. In some embodiments, the compound of unsaturated hydrocarbons contains 4-12 carbon atoms. In some embodiments, R' and / or R" are linear molecules (e.g., straight-chain unsaturated hydrocarbons). In some embodiments, R' and / or R" are branched. In some embodiments, the compound of unsaturated hydrocarbons contains or consists essentially of 3-hexyne. As used in this manner, the term "consisting essentially of..." means that the compound is greater than or equal to about 95%, 98%, 99% or 99.5% unsaturated hydrocarbons (on a molar basis). In some embodiments, the compound of unsaturated hydrocarbons contains 5-decyne or consists essentially of 5-decyne.

[0048] In some embodiments, the substrate is immersed in a vapor of an unsaturated hydrocarbon. In some embodiments, the processing conditions under which the substrate is exposed to the unsaturated hydrocarbon can be controlled.

[0049] In some embodiments, the pressure of the processing chamber is controlled. The pressure of the processing chamber can be any pressure suitable for forming the barrier layer. In some embodiments, the pressure of the processing chamber is maintained at less than or equal to about 80 Torr, less than or equal to about 70 Torr, less than or equal to about 60 Torr, less than or equal to about 50 Torr, less than or equal to about 40 Torr, less than or equal to about 30 Torr, less than or equal to about 20 Torr, less than or equal to about 15 Torr, less than or equal to about 10 Torr, or less than or equal to about 5 Torr. In some embodiments, the pressure of the processing chamber is maintained at about 10 Torr, about 20 Torr, about 25 Torr, about 30 Torr, about 40 Torr, or about 50 Torr.

[0050] In some embodiments, the flow rate of the unsaturated hydrocarbon entering the processing chamber is controlled. The flow rate of the unsaturated hydrocarbon can be any flow rate suitable for forming the barrier layer. In some embodiments, the flow rate of the unsaturated hydrocarbon is in the range of about 50 sccm to about 1000 sccm, about 100 sccm to about 800 sccm, about 400 sccm to about 700 sccm, about 500 sccm to about 650 sccm, or about 550 sccm to about 650 sccm. In some embodiments, the flow rate of the unsaturated hydrocarbon is less than or equal to about 1000 sccm, less than or equal to about 800 sccm, less than or equal to about 700 sccm, less than or equal to about 650 sccm, less than or equal to about 600 sccm, less than or equal to about 550 sccm, less than or equal to about 500 sccm, less than or equal to about 400 sccm, less than or equal to about 300 sccm, or less than or equal to about 200 sccm. In some embodiments, the flow rate of the unsaturated hydrocarbon is greater than or equal to about 50 sccm, greater than or equal to about 100 sccm, greater than or equal to about 200 sccm, greater than or equal to about 300 sccm, less than or equal to about 400 sccm, greater than or equal to about 500 sccm, greater than or equal to about 550 sccm, greater than or equal to about 600 sccm, greater than or equal to about 650 sccm, greater than or equal to about 700 sccm, or greater than or equal to about 800 sccm. In some embodiments, the flow rate of the unsaturated hydrocarbon is about 50 sccm, about 100 sccm, about 200 sccm, about 300 sccm, about 400 sccm, about 500 sccm, about 550 sccm, about 600 sccm, about 650 sccm, about 700 sccm, about 800 sccm, or about 1000 sccm.

[0051] In some embodiments, the immersion time period during which the unsaturated hydrocarbon is exposed to the substrate is controlled. The immersion time period can be any suitable time period for forming the barrier layer. In some embodiments, the immersion time period is greater than or equal to about 10 seconds, greater than or equal to about 20 seconds, greater than or equal to about 30 seconds, greater than or equal to about 45 seconds, greater than or equal to about 60 seconds, greater than or equal to about 90 seconds, greater than or equal to about 120 seconds, greater than or equal to about 150 seconds, greater than or equal to about 200 seconds, or greater than or equal to about 250 seconds. In some embodiments, the immersion time period is less than or equal to about 300 seconds, less than or equal to about 250 seconds, less than or equal to about 200 seconds, less than or equal to about 150 seconds, less than or equal to about 120 seconds, less than or equal to about 90 seconds, less than or equal to about 60 seconds, less than or equal to about 45 seconds, less than or equal to about 30 seconds, or less than or equal to about 20 seconds. In some embodiments, the immersion time period is about 60 seconds. In some embodiments, the immersion time period is about 200 seconds.

[0052] In some embodiments, the temperature of the substrate is controlled during exposure to the unsaturated hydrocarbon. In some embodiments, each operation disclosed herein is performed at approximately the same temperature. In this case, the temperature of the substrate may also be referred to as the operating temperature. In some embodiments, during exposure to the unsaturated hydrocarbon, the temperature of the substrate is less than or equal to about 300°C, less than or equal to about 275°C, less than or equal to about 250°C, less than or equal to about 225°C, less than or equal to about 200°C, or less than or equal to about 150°C. In some embodiments, during exposure to the unsaturated hydrocarbon, the temperature of the substrate is greater than or equal to about 100°C, greater than or equal to about 150°C, greater than or equal to about 200°C, greater than or equal to about 225°C, greater than or equal to about 250°C, or greater than or equal to about 275°C.

[0053] In some embodiments, the unsaturated hydrocarbon compound is a liquid at the operating temperature. In some embodiments, the hydrocarbon compound has a vapor pressure greater than or equal to about 0.1 Torr at the operating temperature.

[0054] In some embodiments, method 100 continues deposition at operation 170 by depositing a first film 140 on second surface 122 as compared to blocked first surface 132. First film 140 can be deposited by any technique known to those skilled in the art. First film 140 is deposited on second surface 122. In some embodiments, first material 110 comprises a conductive material and second material 120 comprises an insulating material, and thus the method can be referred to as "reverse selective deposition." Those skilled in the art will understand that the term "selective deposition" is generally used to form a film on a conductive material as compared to an insulating material. A reverse selective deposition process forms a film on an insulating material.

[0055] In some embodiments, the first film 140 is deposited by atomic layer deposition. In some embodiments, the first film 140 is deposited by sequentially exposing the substrate 105 to a metal precursor and a reactant. In some embodiments, the film 140 comprises a metal nitride.

[0056] In some embodiments, the first film 140 functions as a barrier film. In some embodiments, the first film 140 comprises or consists essentially of titanium nitride. In some embodiments, the first film 140 comprises or consists essentially of tantalum nitride. In some embodiments, the metal precursor comprises pentakis(dimethylamino)tantalum. In some embodiments, the reactant comprises ammonia. In some embodiments, the first film 140 is formed without the use of a plasma.

[0057] In some embodiments, method 100 optionally includes a post-treatment process prior to removing the barrier layer. Without being bound by theory, it is believed that the post-treatment may also help facilitate the removal of the barrier layer. In some embodiments, the post-treatment comprises exposing the substrate to a reactant comprising or consisting essentially of one or more of hydrogen (H2), ammonia, water, or oxygen (O2). In some embodiments, the reactant is substantially free of hydrogen (H2). In some embodiments, the reactant is substantially free of oxygen (O2). In some embodiments, the post-treatment reactant is provided in the absence of a plasma (e.g., heat).

[0058] Method 100 continues at operation 180 by removing barrier layer 130 from modified first surface 115. Barrier layer 130 can be removed by any suitable means, including, but not limited to, a plasma cleaning process. In some embodiments, substrate 105 is exposed to a plasma to remove barrier layer 130 from modified first surface 115. In some embodiments, the plasma includes or consists essentially of one or more of argon (Ar), nitrogen (N2), hydrogen (H2), or ammonia. As used herein, a plasma containing nitrogen, hydrogen, oxygen, or the like refers to a plasma formed from the molecular form of the substances. For example, a nitrogen plasma refers to a plasma excited by molecular nitrogen (N2). As used herein and in the appended claims, an element-containing plasma (e.g., a nitrogen-containing plasma) refers to a compound containing the element. For example, a nitrogen-containing plasma includes or consists essentially of one or more compounds having nitrogen as an element (e.g., ammonia (NH3)). In some embodiments, the plasma consists essentially of argon. In some embodiments, the plasma comprises or consists essentially of a mixture of H 2 and Ar.

[0059] In some embodiments, the mixture of H2 and Ar has a H2:Ar ratio in the range of about 10:1 to about 1:10, in the range of about 10:1 to about 1:1, in the range of about 1:1 to about 1:10, in the range of about 5:1 to about 1:5, in the range of about 5:1 to about 1:1, in the range of about 1:1 to about 1:5, in the range of about 2:1 to about 1:2, in the range of about 2:1 to about 1:1, or in the range of about 1:1 to about 1:2. In some embodiments, the mixture of H2 / Ar is about 1:1.

[0060] The power of the plasma can vary depending on the composition, fill, and / or thickness of the barrier layer and the composition and / or thickness of the surrounding material. In some embodiments, the plasma power is in the range of about 200 W to about 1000 W, in the range of about 300 W to about 800 W, in the range of about 400 W to about 600 W, in the range of about 200 W to about 800 W, in the range of about 200 W to about 600 W, in the range of about 400 W to about 1000 W, or in the range of about 400 W to about 800 W. In some embodiments, the plasma power is about 300 W, about 400 W, about 500 W, about 600 W, or about 700 W.

[0061] The duration of the plasma exposure can vary depending on the composition, fill, and / or thickness of the barrier layer 130 and the composition and / or thickness of the surrounding materials. In some embodiments, the substrate is exposed to the plasma for a period of time in the range of about 2 seconds to about 600 seconds, in the range of about 5 seconds to about 300 seconds, or in the range of about 10 seconds to about 200 seconds. In some embodiments, the substrate is exposed to the plasma for a period of time of about 15 seconds, about 30 seconds, about 60 seconds, about 100 seconds, about 200 seconds, or about 300 seconds.

[0062] Method 100 may continue by depositing a second film on the substrate surface. Although this operation is not Figure 1 , the parameters of the operations are described in detail below with respect to operations 290 and 390 .

[0063] refer to Figure 2 The exemplary reverse selective deposition method 200 begins by providing a substrate 205 having a substrate top surface 202 with at least one feature 206 formed therein. The various films and layers described are similar to Figure 1 As shown, those skilled in the art will recognize that these are merely different structural forms of similar methods.

[0064] The at least one feature extends from the substrate top surface 202 a depth into the substrate to a bottom 209 and has a width between a first sidewall 207 and a second sidewall 208. In the illustrated embodiment, the sidewalls 207, 208 include and are formed from a first material 210. The bottom 209 includes and is formed from a second material 220. The at least one feature 206 can have one sidewall (e.g., a circular via), two sidewalls (e.g., a trench), or more sidewalls (e.g., a square or polygonal via).

[0065] The method continues at operation 250 by exposing the substrate surface to a surface pretreatment to modify at least the first surface 112 and form a modified first surface 115. The parameters of the pretreatment are disclosed above with respect to operation 150.

[0066] Method 200 continues at operation 260 by exposing substrate 205 to a barrier compound to selectively form a barrier layer 230 on modified first surface 215 of first material 210 forming bottom 209 of feature 206 as compared to second surface 222 of second material 220 forming substrate top surface 202 and feature sidewalls 207, 208. In other words, substrate 205 is treated with the barrier compound to inactivate or block future deposition on first material 210.

[0067] Method 200 continues at operation 270 by selectively depositing a first film 240 on second surface 222 relative to barrier layer 230. In some embodiments, operation 270 represents a reverse selective deposition process. Again, those skilled in the art will understand that the term "reverse selective deposition" refers to a selective deposition process in which a film is formed on a surface of an insulating material. In some embodiments, first film 240 is deposited by sequentially exposing substrate 205 to a metal precursor and a reactant. In some embodiments, first film 240 comprises a material that functions as a barrier layer.

[0068] At operation 280 , method 200 continues by removing barrier layer 230 from first surface 212 of first material 210 on bottom 209 of feature 206 .

[0069] Without wishing to be bound by theory, it is believed that the continued presence of the barrier layer 230 causes problems with deposited material pull-out due to poor adhesion between the first material 210 and the subsequently deposited second film 245. Additionally, the continued presence of the barrier layer 230 may contribute to the formation of a bottom void between the first material 210 and the second film 245.

[0070] After removing barrier layer 230 at operation 280, method 200 continues at operation 290 by depositing second film 245 within at least one feature 206 to form a low resistance metal via. In some embodiments, second film 245 is a conductive material that facilitates electrical contact between first material 210 through feature 206.

[0071] Figure 3 The diagram shows Figure 1 and Figure 2 Another embodiment of the present disclosure is similar to those shown in . Figure 3 The illustrated method 300 is performed using the same materials and overall processing as previously described. Figure 3 The embodiment shown shows a method for forming a connection M x and M x+1Method 300 of via metal lines, as will be appreciated by those skilled in the art. For simplicity, processing the first surface (similar to operations 150 and 250 ) to form modified first surface 315 is not shown. Figure 3 A substrate 305 is shown having a first material 310 comprising a conductive material and a second material 320 comprising an insulating material. A feature 306 having multiple layers or levels is formed in the substrate 305. The feature 306 has a lower portion 306a and an upper portion 306b. The lower portion has sidewalls 307a, 308a and a bottom 309a. The upper portion has sidewalls 307b, 308b and a bottom 309b. The sidewalls 307a, 307b, 308a, 308b are formed from the second material 320. The bottom 309a of the lower portion 306a is formed from a modified first surface 315 of the first material 310. The first material 310 is also referred to as M x The bottom portion 309 b is formed by the upper surface 323 of the second material 320 .

[0072] Although Figure 3 Not shown, the method 300 has pre-treatment operations similar to the previously disclosed methods 100, 200. As described above, the first material 310 has a modified first surface 315.

[0073] In process 360, the substrate is exposed to a barrier compound to selectively form a barrier layer 330 on a surface 315 of the first material 310 forming the bottom 309a of the lower portion 306a of the feature 306 compared to a surface of the second material 320 forming the substrate top surface 302, sidewalls 307a, 307b, 308a, 308b, and bottom 309b forming the upper segment surface 323.

[0074] The method 300 continues at operation 370 by selectively depositing a barrier layer 340 on the second material 320 compared to the barrier layer 330. Figure 3 As shown, barrier layer 340 is selectively deposited on sidewalls 307a, 307b, 308a, 308b, bottom 309b, and substrate top surface 302 of upper surface 323 of second material 320. Barrier layer 340 is deposited on exposed surfaces of second material 320, but not on exposed surfaces of first material 310. Barrier layer 340 can be deposited by any suitable technique known to those skilled in the art. In some embodiments, barrier layer 340 is deposited by sequentially exposing substrate 305 to a metal precursor and a reactant.

[0075] At operation 380 , method 300 includes removing barrier layer 330 from modified first surface 315 of first material 310 on bottom 309 a of lower portion 306 a of feature 306 .

[0076] Method 300 continues with selective via deposition at operation 390. A second film 350 comprising a conductive fill material is deposited at least within the lower portion 306 a of feature 306 to form a low-resistance metal via. In the illustrated embodiment, second film 350 is formed only within the lower portion 306 a of feature 306. However, those skilled in the art will recognize that the conductive fill material can be deposited to fill the entire feature 306, including the upper portion 306 b.

[0077] In a similar Figure 3 In the embodiment shown, the second film 350 is grown in a bottom-up manner to fill the through-hole portion of the lower portion 306a of the feature 306, and the third film 355 is deposited in the upper portion 306b. Figure 3 As shown, the upper portion 306b of the feature 306 is filled with a third film 355 comprising a conductive material to form an M x+1 wire.

[0078] The third film 355 can be any suitable material known to those skilled in the art. In the illustrated embodiment, the first material 310 and the third film 355 are the same material, while the second film 350 is a different material. For example, in some embodiments, the first material 310 and the third film 355 include copper, and the second film 350 includes cobalt. In some embodiments, the second film 350 and the third film 355 are the same material. In some embodiments, the entire feature 306 is filled with a single material at a time, thereby filling the lower portion 306a and the upper portion 306b of the feature 306 in a single process.

[0079] The third film 355 can be deposited by any suitable technique known to those skilled in the art. In some embodiments, the third film 355 is deposited by one or more of a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, or a physical vapor deposition (PVD) process. In some embodiments, the third film 355 is deposited to overfill the features 306 and form an overburden on the top surface 302 of the substrate 305. The overburden is then removed by any suitable technique (e.g., etching, chemical mechanical planarization (CMP)).

[0080] refer to Figure 4 , additional embodiments of the present disclosure relate to a processing system 900 for performing the methods described herein. Figure 4A system 900 is illustrated that can be used to process substrates according to one or more embodiments of the present disclosure. The system 900 can be referred to as a cluster tool. The system 900 includes a central transfer station 910 having a robot 912 therein. The robot 912 is shown as a single-blade robot; however, those skilled in the art will recognize that other robot 912 configurations are within the scope of the present disclosure. The robot 912 is configured to move one or more substrates between chambers 920, 930, 940, 960 connected to the central transfer station 910.

[0081] At least one pre-clean / buffer chamber 920 can be connected to the central transfer station 910. The pre-clean / buffer chamber 920 can include one or more of a heater, a radical source, or a plasma source. The pre-clean / buffer chamber 920 can serve as a holding area for individual semiconductor substrates or chip cassettes for processing. The pre-clean / buffer chamber 920 can perform a pre-cleaning process, preheat substrates for processing, or simply serve as a staging area for process steps. In some embodiments, two pre-clean / buffer chambers 920 are connected to the central transfer station 910.

[0082] exist Figure 4 In the illustrated embodiment, the pre-clean chamber 920 can serve as a pass-through chamber between the factory interface 905 and the central transfer station 910. The factory interface 905 can include one or more robots 906 to move substrates from the cassette to the pre-clean / buffer chamber 920. Robots 912 can then move substrates from the pre-clean / buffer chamber 920 to other chambers within the system 900.

[0083] A first processing chamber 930 can be connected to the central transfer station 910. The first processing chamber 930 can be configured as a surface pretreatment chamber and / or a barrier layer deposition chamber for modifying the first surface and forming a barrier layer. The first processing chamber 930 can be in fluid communication with one or more reactive gas sources to provide one or more reactive gas streams to the first processing chamber 930. Substrates can be moved into and out of the processing chamber 930 via a robot 912 through an isolation valve 914.

[0084] A processing chamber 940 can also be connected to the central transfer station 910. In some embodiments, the processing chamber 940 comprises a film deposition chamber and is in fluid communication with one or more reactive gas sources to provide a flow of reactive gas to the processing chamber 940 to perform a deposition process. Substrates can be moved into and out of the processing chamber 940 by a robot 912 through an isolation valve 914.

[0085] In some embodiments, the processing chamber 960 is connected to the central transfer station 910 and is configured to function as a barrier layer removal chamber.The processing chamber 960 can be configured to perform one or more deposition processes.

[0086] In some embodiments, each of the process chambers 930, 940, and 960 is configured to perform a different portion of a processing method. For example, process chamber 930 may be configured to perform a pre-processing and / or barrier layer formation process, process chamber 940 may be configured to perform one or more film deposition processes, and process chamber 960 may be configured to perform a barrier layer removal process. Those skilled in the art will recognize that the number and arrangement of the various process chambers on a tool may vary, and Figure 4 The embodiment shown in represents only one possible configuration.

[0087] In some embodiments, the processing system 900 includes one or more metrology stations. For example, the metrology station can be located within the pre-clean / buffer chamber 920, within the central transfer station 910, or within any individual processing chamber. The metrology station can be any location within the system 900 that allows for measurement of a characteristic of a substrate without exposing the substrate to the surrounding environment.

[0088] At least one controller 950 is coupled to one or more of the central transfer station 910, the pre-clean / buffer chamber 920, or the processing chambers 930, 940, or 960. In some embodiments, there is more than one controller 950 connected to each chamber or station, and a main control processor is coupled to each individual controller to control the system 900. The controller 950 can be any form of general-purpose computer processor, microcontroller, microprocessor, etc., which can be used in an industrial environment to control various chambers and sub-processors.

[0089] At least one controller 950 may have a processor 952, a memory 954 coupled to the processor 952, an input / output device 956 coupled to the processor 952, and support circuits 958 for communication between the various electronic components. The memory 954 may include one or more of a transient memory (e.g., random access memory) and a non-transient memory (e.g., storage).

[0090] The processor's memory 954 or computer-readable medium can be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), a floppy disk, a hard disk, or any other form of local or remote digital storage. The memory 954 can retain an instruction set operable by the processor 952 to control the parameters and components of the system 900. Support circuits 958 are coupled to the processor 952 for supporting the processor in a conventional manner. The circuits may include, for example, caches, power supplies, clock circuits, input / output circuits, subsystems, or the like.

[0091] The process can be typically stored in a memory as a software routine that, when executed by a processor, causes the processing chamber to perform the process of the present disclosure. The software routine can also be stored and / or executed by a second processor (not shown) of the hardware remote from the processor control. Some or all of the methods of the present disclosure can also be performed in hardware. In this way, the process can be implemented in software and performed using a computer system, in hardware as (for example) an ASIC or other type of hardware, or as a combination of software and hardware. When executed by a processor, the software routine converts a general-purpose computer into a special-purpose computer (controller) that controls the operation of the chamber, thereby performing the process.

[0092] In some embodiments, the controller 950 has one or more configurations to execute individual processes or sub-processes to perform the method. The controller 950 can be connected and configured to operate intermediate components to perform the functions of the method. For example, the controller 950 can be connected and configured to control one or more of a gas valve, an actuator, a motor, a slit valve, a vacuum control, and the like.

[0093] The controller 950 of some embodiments has one or more configurations selected from the following: a configuration for moving a substrate on a robot between multiple processing chambers or metrology stations; a configuration for loading and / or unloading a substrate from a system; a configuration for pre-treating a first surface of a substrate; a configuration for forming a barrier layer on a modified first surface; a configuration for selectively depositing a first film on a second surface; a configuration for removing a barrier layer; and / or a configuration for depositing a second film on a first material and / or a first film.

[0094] Example

[0095] Several cobalt substrates were processed as shown below in Table 1. Following the treatments of Table 1, each substrate was treated with 36 cycles of ALD deposition treatment and 30 seconds of post-deposition plasma treatment.

[0096] Table 1

[0097]

[0098] The inventors found that when a barrier layer is deposited, using a pre-treatment prior to removal provides more deposition. This result indicates that barrier layer removal is more efficient.

[0099] References throughout this specification to "one embodiment," "certain embodiments," "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 invention. Thus, the appearance of phrases such as "in one or more embodiments," "in certain embodiments," "in one embodiment," or "in an embodiment" in various places throughout this specification do not necessarily refer to the same disclosed embodiment. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0100] Although the disclosure herein has been described with reference to specific embodiments, it will be understood by those skilled in the art 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 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 within the scope of the appended claims and their equivalents.

Claims

1. A reverse selective deposition method comprising the following steps: exposing a substrate comprising a first material having a first surface and a second material having a second surface to a surface pretreatment to modify the first surface and form a modified first surface, wherein the surface pretreatment step comprises the steps of: exposing the first surface to a nitrogen-containing reactant, wherein exposing the first surface to the nitrogen-containing reactant chemisorbs nitrogen atoms to at least a portion of the first surface and forms the modified first surface, and wherein the top surface of the substrate comprises at least one feature, the at least one feature extending into the depth of the substrate to a bottom, the at least one feature having a width between a first sidewall and a second sidewall, the first sidewall and the second sidewall being comprised of the second material, the bottom being comprised of the first material, the first material comprising a conductive material and the second material comprising an insulating material; exposing the substrate to a barrier compound comprising 5-decyne to selectively form a barrier layer on the modified first surface, wherein the nitrogen atoms are intercalated between at least some molecules of the barrier layer and the first surface; A barrier film is selectively deposited on the second surface compared to the barrier layer, the barrier film being composed of tantalum nitride or titanium nitride; exposing the barrier film and the barrier layer to a post-treatment, wherein the post-treatment comprises exposing the substrate to a reactant comprising or consisting of one or more of hydrogen, ammonia, water, or oxygen; removing the barrier layer from the first material; and After removing the barrier layer, depositing a second film on the barrier film and the first material, Wherein the nitrogen-containing reactant is exposed to the first surface in the absence of a plasma, the surface pretreatment facilitates the removal of the barrier layer from the first surface.

2. The method according to claim 1, wherein The conductive material includes one or more of copper, cobalt, tungsten, molybdenum or ruthenium.

3. The method according to claim 1, wherein The insulating material includes one or more of silicon oxide, silicon nitride, or low-k dielectric.

4. The method of claim 1 , wherein the nitrogen-containing reactant comprises hot ammonia NH 3 .

5. The method of claim 1, wherein the barrier film is deposited by sequentially exposing the substrate surface to a metal precursor and a reactant.

6. The method of claim 5, wherein the metal precursor comprises pentakis(dimethylamino)tantalum, the reactant comprises ammonia and the barrier film comprises tantalum nitride.

7. The method of claim 1 , wherein the step of removing the barrier layer comprises the following steps: The substrate surface is exposed to a plasma formed from a plasma gas.

8. The method of claim 7, wherein: The plasma gas includes hydrogen H2 and argon.

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