Ruthenium CMP chemicals based on halogenation

Abstract

The present disclosure provides novel corrosion control chemistries for use in ruthenium (Ru) chemical mechanical polishing (CMP) processes. More specifically, the present disclosure provides improved CMP slurry chemistries and CMP processes for planarizing ruthenium surfaces. In the CMP process disclosed herein, a ruthenium surface (e.g., a post-etch ruthenium surface) is exposed to a CMP slurry containing a halogenating agent that reacts with the ruthenium surface to form a ruthenium halide surface and a ligand for ligand-assisted reactive dissolution of the ruthenium halide surface. The relative amounts of the halogenating agent and ligand in the CMP slurry can be controlled to provide a diffusion-limited etch process that improves post-etch surface morphology while providing high material removal rates.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 257,214, “RUTHENIUM CMP CHEMISTRY BASED ON HALOGENATION,” filed on 19 October 2021, to U.S. Patent Application No. 17 / 674,593, also titled “RUTHENIUM CMP CHEMISTRY BASED ON HALOGENATION,” filed on 17 February 2022, and to U.S. Patent Application No. 17 / 674,579, also titled “METHOD FOR WET ATOMIC LAYER ETCHING OF RUTHENIUM,” filed on 17 February 2022, the disclosures of which are expressly incorporated herein by reference. [Background technology]

[0002] This disclosure relates to the manufacture of semiconductor devices, and more specifically, to the removal and etching of polycrystalline materials such as metals. During normal semiconductor manufacturing, various metals formed on a substrate may be removed by patterned etching, chemical mechanical polishing (CMP), and other techniques. Various techniques are known for etching layers on a substrate, including plasma-based or vapor-phase etching (called dry etching) and liquid-based etching (called wet etching).

[0003] Chemical mechanical polishing (CMP) has become an indispensable tool for planarization in semiconductor manufacturing. CMP uses a slurry containing solvents, abrasive particles, and reactive chemicals designed to erode the surface being polished. The combination of surface reaction and abrasive action enhances material removal at higher levels on the surface, thus planarizing it.

[0004] One of the challenges in chemical mechanical polishing is surface corrosion. Surface corrosion must be well controlled to prevent pitting, accumulation of corrosion products on the substrate surface, and surface damage due to mechanical removal of insoluble products. However, surface corrosion control should not be done at the expense of throughput; that is, the corrosion rate must be high to support material removal rates compatible with mass production.

[0005] Ruthenium (Ru) is a noble metal currently being considered as a substitute for copper in back-end-of-line (BEOL) metallization, as well as for front-end-of-line (FEOL) features such as embedded power rails (power rails located beneath active devices). However, the noble metal properties of ruthenium make etching and planarizing Ru difficult.

[0006] For example, U.S. Patent Application No. 17 / 580,936, filed on January 21, 2022, which is concurrently pending, describes a wet ALE process for etching various transition metals, including ruthenium. In the concurrently pending application, a modified surface layer is formed by exposing the surface of a Ru metal to an oxidizing agent, which forms a metal oxide on the exposed surface. While it is easy to form a ruthenium dioxide (RuO2) surface layer using a chemical solution containing dissolved oxygen or another oxidizing agent, the stability and insolubility of this surface oxide are difficult to handle in the etching process. Therefore, strong oxidizing agents are typically used in conventional etching processes to form soluble or volatile ruthenium-oxide compounds.

[0007] Some commercially available ruthenium etchants contain strong oxidizing agents such as sodium hypochlorite, cerium ammonium nitrate, and periodic acid, which oxidize the ruthenium surface to form ruthenium tetroxide (RuO4). Of these chemicals, cerium ammonium nitrate and sodium hypochlorite, the most effective etchants, are problematic because they pose a risk of metal contamination in the subsequently formed device. For example, the incorporation of trace amounts of sodium and cerium in the front-end of line can significantly degrade transistor performance. On the other hand, periodic acid is expensive and cannot be used to provide a cost-effective etching process for ruthenium.

[0008] Another challenge with conventional etching processes used to etch ruthenium is the tendency for the resulting surface to be rough. This is because ruthenium grain boundaries tend to be far more reactive than the grain surface, leading to selective etching at the grain boundaries compared to the grain surface. Thus, chemical-mechanical polishing is often used in conventional processes to smooth the ruthenium surface after etching.

[0009] Like ruthenium etching chemicals, conventional ruthenium CMP slurries generally rely on strong oxidizing agents to corrode the ruthenium surface. Similar to etching, these oxidizing agents tend to react selectively with particle boundaries, which leads to pitting of the Ru surface during CMP. While less invasive oxidizing agents can be used to reduce pitting, using such oxidizing agents in a CMP slurry significantly reduces the material removal rate. Since the corrosion products are no longer soluble, the material removal rate decreases drastically, and therefore mechanical polishing becomes the only process for material removal.

[0010] There is a need for novel ruthenium CMP slurry chemicals that provide high material removal rates while improving surface smoothness after etching. [Overview of the Initiative] [Means for solving the problem]

[0011] This disclosure provides novel corrosion control chemicals for ruthenium (Ru) CMP processes. More specifically, this disclosure provides novel ruthenium CMP slurry chemicals that utilize halogenation of a ruthenium surface to form ruthenium halide or ruthenium oxyhalide surface intermediates, and reactive dissolution to chemically remove the ruthenium halide or ruthenium oxyhalide surface intermediates. Halogenation of the ruthenium surface can be achieved using radical halogenation of a chemical halogenating agent. The halogenation is self-limiting, and the kinetics of the reactive dissolution are temperature-dependent. The self-limiting nature of the halogenation limits pitting of the ruthenium surface. Since the mechanical polishing process increases the local temperature around higher positions on the surface, the temperature-dependent kinetics of the dissolution are further helpful in planarizing the ruthenium surface.

[0012] According to one embodiment, an improved chemical mechanical polishing (CMP) process for planarizing a ruthenium surface is provided herein. In the CMP process disclosed herein, a ruthenium surface (e.g., a ruthenium surface after etching) may be exposed to a CMP slurry containing a halogenating reagent that reacts with the ruthenium halide or oxyhalide surface to form a ruthenium halide or oxyhalide surface, and a ligand for ligand-assisted reactive dissolution of the ruthenium halide or oxyhalide surface. The relative amounts of halogenating agent and ligand in the CMP slurry can be controlled to provide a diffusion-limited etching process that improves the surface morphology after etching while providing a high material removal rate.

[0013] For this process, a wide variety of halogenating reagents (e.g., trichloroisocyanuric acid (TCCA)) can be used in a non-aqueous solvent (e.g., ethyl acetate (EA)). Since the ruthenium halide or oxyhalide surface is insoluble in non-aqueous solvents, ligand-assisted reactive dissolution is used to facilitate the chemical removal of the ruthenium halide or oxyhalide surface. A wide variety of ligands (e.g., acetylacetone (ACAC) or aminopolycarboxylic acid) can be used for the reactive dissolution of the ruthenium halide or oxyhalide surface.

[0014] According to other embodiments, compositions comprising novel CMP slurries are provided herein. The novel CMP slurry may generally comprise a solvent, a halogenating agent that halogenates a ruthenium surface to form a ruthenium halide surface, a ligand that reacts with the ruthenium halide surface to dissolve it, and a catalyst that increases the rate of ligand exchange reaction with the ruthenium halide surface. In some embodiments, the relative amounts of halogenating agent and ligand in the CMP slurry may be selected to result in a halogenation rate of the ruthenium surface that is greater than the dissolution rate of the ruthenium halide surface.

[0015] In some embodiments, the CMP slurry described herein contains a halogenating agent but does not contain an oxide-forming oxidizing agent. As used herein, an oxide-forming oxidizing agent is an oxidizing agent that reacts with the ruthenium surface to form a ruthenium oxide layer on the ruthenium surface. While halogenating agents can halogenate and chemically oxidize the ruthenium surface, they do not react with the ruthenium surface to form a ruthenium oxide layer on the ruthenium surface.

[0016] In other embodiments, the CMP slurry described herein may contain a halogenating agent and an oxide-forming oxidizing agent. For example, the CMP slurry may further contain a predetermined amount of water or dissolved oxygen. When halogenation is carried out in the presence of an oxide-forming oxidizing agent such as water or dissolved oxygen, a ruthenium halide surface containing ruthenium oxide-halogen species is formed on the ruthenium surface. Since ruthenium oxide-halogen species are generally more soluble than the ruthenium halide surface layer, the presence of ruthenium oxide-halogen species increases the material removal rate in the CMP process.

[0017] In some embodiments, the halogenating agent contained in the CMP slurry may be a chlorinating agent. In such embodiments, the chlorinating agent may react with the ruthenium surface to form a chlorinated ruthenium surface, and the ligand may be reactive to the chlorinated ruthenium surface.

[0018] In some embodiments, the halogenating agent may include a chlorinating agent dissolved in a solvent. For example, the chlorinating agent may be trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, or N-chlorosuccinimide, and the solvent may be ethyl acetate, acetone, acetonitrile, or chlorocarbon. In such embodiments, the halogenating agent can react with the ruthenium surface to form a self-limiting RuCl3 passivation layer.

[0019] It should be noted that the halogenating agents disclosed herein are not strictly limited to chlorinating agents. In some embodiments, for example, the halogenating agent may be a fluorinating agent. In such embodiments, the fluorinating agent may react with the ruthenium surface to form a fluorinated ruthenium surface, and the ligand may be reactive to the fluorinated ruthenium surface. In other embodiments, the halogenating agent may be a brominating agent. In such embodiments, the brominating agent may react with the ruthenium surface to form a brominated ruthenium surface, and the ligand may be reactive to the brominated ruthenium surface.

[0020] In some embodiments, the ligand contained in the CMP slurry may include ethylenediaminetetraacetic acid (EDTA), acetylacetone (ACAC), iminodiacetic acid (IDA), or diethylenetriaminepentaacetic acid (DTPA), and the catalyst may be a base. Examples of bases that may be included in the CMP slurry to increase the rate of the ligand exchange reaction with the ruthenium halide surface include, but are not limited to, potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH), and tetramethylammonium hydroxide ((CH3)4NOH).

[0021] In some embodiments, the CMP slurry may be non-aqueous and may include polishing particles. In one exemplary implementation, the CMP slurry disclosed herein may use EA as a solvent and may further contain a nanoparticle abrasive (e.g., silicon dioxide (SiO2)), a halogenating reagent (e.g., TCCA), a ligand (e.g., aminopolycarboxylic acid), and a base that catalyzes ligand-assisted reactive dissolution.

[0022] Thus, the technology disclosed herein provides a ruthenium CMP process and a ruthenium CMP slurry that mainly use halogenation to form a ruthenium-halogen compound on the ruthenium surface and use ligand-assisted reactive dissolution for chemical removal of the ruthenium-halogen compound. Since different ligands react with the halogenated surface at different rates, various different ligands can be used to adjust the chemical etching rate achieved during a given CMP process. One advantage of the CMP process and CMP slurry described herein is that the chemical and mechanical properties of the ruthenium-halogen compound are more suitable for the CMP process. Thus, the CMP process and CMP slurry described herein improve the smoothing of the ruthenium surface after etching while providing a high material removal rate.

[0023] As further described herein, the present disclosure provides various embodiments of methods of using the novel CMP chemistries disclosed herein to planarize a ruthenium surface. Of course, the order of consideration of the various steps described herein is presented for clarity. In general, these steps can be performed in any suitable order. Additionally, although each of the various features, techniques, configurations, etc. herein may be described at various places in the present disclosure, each of those concepts is intended to be performed independently of one another or in combination with one another. Thus, the present invention can be embodied and considered in many different ways.

[0024] According to one embodiment, a method of removing ruthenium is provided herein. The method generally begins by placing a substrate within a chemical mechanical polishing (CMP) system, the CMP system including a polishing pad mounted on a rotatable platen, whereby the polishing pad can be rotated to move across the surface of the substrate, the substrate including a ruthenium surface. Next, the method can include dispensing a slurry onto the polishing pad. The slurry can generally include a solvent, a halogenating agent that halogenates the ruthenium surface to form a halogenated ruthenium surface, a ligand that reacts with the halogenated ruthenium surface to dissolve the halogenated ruthenium surface, and a catalyst that increases the rate of the ligand exchange reaction with the halogenated ruthenium surface. Next, the method can include polishing the ruthenium surface using the slurry until a predetermined amount of ruthenium has been removed.

[0025] In some embodiments, the method can further include controlling the relative amounts of the halogenating agent and the ligand in the slurry such that the halogenation rate of the ruthenium surface is greater than the dissolution rate of the halogenated ruthenium surface.

[0026] In some embodiments, distributing the slurry onto the polishing pad may include distributing a slurry that does not contain an oxide-forming oxidizing agent. In other embodiments, distributing the slurry onto the polishing pad may include distributing a slurry that contains a halogenating agent and an oxide-forming oxidizing agent.

[0027] In some embodiments, the halogenating agent may include a chlorinating agent, which reacts with the ruthenium surface to form a chlorinated ruthenium surface. In such embodiments, the ligand can react with the chlorinated ruthenium surface to dissolve it. In some embodiments, a catalyst that increases the rate of ligand exchange with the chlorinated ruthenium surface may be a base.

[0028] Please note that this summary section does not specify all embodiments and / or stepwise novel aspects of the invention as described in this disclosure or claims. Instead, this summary provides only preliminary considerations of various embodiments and aspects corresponding to novelty over the prior art. For further details and / or possible aspects of the invention and embodiments, please refer to the detailed description section of this disclosure and the corresponding drawings detailed below.

[0029] The present invention and its advantages will be better understood by referring to the following description in conjunction with the accompanying drawings showing the same features and reference numbers. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments of the disclosed concept, and therefore the disclosed concept may also encompass other equally effective embodiments, and should not be considered to limit the scope of the invention. [Brief explanation of the drawing]

[0030] [Figure 1] This is a block diagram of a chemical mechanical polishing (CMP) system. [Figure 2] This is a flowchart illustrating one embodiment of a method for utilizing the technology described herein. [Modes for carrying out the invention]

[0031] Etching ruthenium with liquid (wet) chemicals has traditionally involved using strong oxidizing agents to form soluble ruthenium species. Currently available Ru etchants include metallic RuO4 or related hydrate species. 0 to Ru 8+ To oxidize ruthenium, cerium ammonium nitrate, periodic acid, and hypochlorite ions are used. However, these oxidations result in a rough surface after etching due to the increased reactivity of ruthenium at grain boundaries. Another weakness of conventional ruthenium wet etching processes is that the reaction products are highly soluble. This solubility leads to oxidation-limited etching, which only exacerbates the formation of roughness during etching. These weaknesses are amplified when the same oxidizing agents are used as part of the Ru CMP slurry. Therefore, novel etching chemicals are needed for use in Ru CMP for better ruthenium removal.

[0032] This disclosure provides novel CMP slurry chemicals for planarizing ruthenium (Ru) surfaces. As will be described in more detail below, the Ru CMP slurry described herein comprises a halogenating agent for chemically modifying the ruthenium surface to form a passivation layer of ruthenium halide or oxyhalide on the ruthenium surface; a ligand for the reactive dissolution of the passivation layer of ruthenium halide or oxyhalide; a strong base or other catalyst for increasing the ligand reaction rate; and an abrasive grinding medium in a non-aqueous solvent. Surfactants or other stabilizers may also be used to help keep all of these components dissolved or suspended in the CMP slurry.

[0033] Unlike conventional CMP slurry chemicals used to planarize ruthenium, the CMP slurry chemicals disclosed herein prefer Ru to achieve a higher oxidation state than that achieved with conventional RuCMP slurries. 0 to Ru 3+The focus is on oxidation. Using lower oxidation states has the advantage of providing options for forming soluble and insoluble ruthenium products. The CMP slurry chemicals disclosed herein achieve lower oxidation states primarily by using halogenation rather than oxidation of the ruthenium surface, thereby forming a passivation layer of ruthenium halides or oxyhalides. 0 The direct halogenation of Ru 3+ This leads to the formation of X3 (where X is a halogen). In some embodiments, halogenation can be achieved by exposing the ruthenium surface to a CMP slurry containing a chlorinating agent, a fluorinating agent, or a brominating agent.

[0034] Chlorination of ruthenium surfaces can be achieved using a wide variety of chlorinating reagents, including trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, and N-chlorosuccinimide. Exposure of the ruthenium surface to these chlorinating agents chemically modifies the surface, forming a ruthenium chloride passivation layer, such as but not limited to ruthenium trichloride (RuCl3). It should be noted that this is not an exhaustive list of all possible chlorinating agents that can be used to form a ruthenium chloride passivation layer. Furthermore, it should be noted that the ruthenium surface can be exposed to other halogenating agents to form other ruthenium halide or oxyhalide passivation layers. For example, fluorination or bromination of ruthenium surfaces can be achieved using fluorinating or brominating agents such as 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate, N-fluorobenzenesulfonimide, N-bromosuccinimide, or dibromoisocyanuric acid. Exposure to these halogenating agents forms a ruthenium fluoride or ruthenium brominated passivation layer on the ruthenium surface. Halogenating agents are generally hydrolyzed by water. Therefore, regardless of the halogenating agent used, halogenation must occur in a solvent or solvent blend in which hydrolysis does not occur.

[0035] In one exemplary embodiment, a CMP slurry according to the present disclosure can include TCCA dissolved in a non-aqueous solvent such as ethyl acetate (EA), acetone, acetonitrile, or a chlorocarbon. When exposed to TCCA in a non-aqueous solvent such as ethyl acetate, Ru 0 rapidly reacts to form a self-limiting ruthenium chloride (RuCl3) passivation layer. If an oxide-forming oxidant such as water or dissolved oxygen is present during the chlorination reaction, the self-limiting ruthenium chloride passivation layer can also contain RuO x Cl y species. "Self-limiting" means that only a limited thickness of the ruthenium surface is modified or removed, regardless of how long a given etching solution is in contact with the ruthenium surface. A self-limiting reaction can be limited by one or more monolayers of the reaction or a partial monolayer of the reaction. Once formed, the ruthenium chloride passivation layer can be solubilized via a ligand exchange reaction. By adding a reactive ligand to the non-aqueous TCCA solution, the CMP slurry chemistry described herein is converted from a self-limiting surface passivation to a continuous etching process.

[0036] A wide variety of ligands may be used in the CMP slurry to chemically remove the ruthenium chloride passivation layer via ligand-assisted reactive dissolution. For example, ligands such as acetylacetone (ACAC) or aminopolycarboxylic acid ligands work well for ligand-assisted dissolution of insoluble RuCl3. Ethylenediaminetetraacetic acid (EDTA) is an exemplary aminopolycarboxylic acid that reacts with RuCl3 to form ruthenium aminopolycarboxylate. Alternative ligands for the reactive dissolution of insoluble RuCl3 include, but are not limited to, iminodiacetic acid (IDA) and diethylenetriaminepentaacetic acid (DTPA). EDTA, IDA, and DTPA can be used in aqueous solutions, while ACAC can be used in aqueous solutions, ethanol, dimethyl sulfoxide (DMSO), or other organic solvents. In some embodiments, ligands contained in the CMP slurry can be used to adjust the chemical etching rate achieved during a given CMP process. For example, different ligands react with the ruthenium chloride passivation layer (or other ruthenium halide surface layer) at different rates. Since the reaction kinetics strongly depend on the reactivity of the ligand used, different ligands can be selected and used to adjust the chemical etching rate achieved during a given CMP process.

[0037] Ligand exchange reactions (e.g., substituting EDTA with a Cl ligand) are base-catalyzed. Therefore, a base is required in the CMP slurry to deprotonate EDTA (or ACAC) to form the reactive anionic form of the ligand. A wide variety of bases can be used in the CMP slurry to deprotonate the ligand, including potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH), tetramethylammonium hydroxide ((CH3)4NOH), and other strong bases. Non-aqueous bases (e.g., quaternary ammonium hydroxides, trialkylamines) or basic solvents (e.g., amino alcohols) can also be used.

[0038] Therefore, in one embodiment, the CMP slurry described herein may contain TCCA for promoting the chlorination reaction with the ruthenium surface to form a ruthenium chloride (e.g., RuCl3) passivation layer on the ruthenium surface, a ligand such as ACAC or EDTA for ligand-assisted reactive dissolution of the ruthenium chloride passivation layer, and a base or other catalyst for increasing the rate of the ligand reaction and continuously etching the ruthenium surface. By changing the concentrations of TCCA and ligand in the slurry solution, the relative kinetic rates of the chlorination reaction and the ligand-assisted dissolution reaction can be adjusted.

[0039] As described above, conventional ruthenium wet etching chemicals and CMP slurries rely on oxidation-restricted etching, which increases surface roughness during etching and planarization. In contrast, the techniques described herein improve post-etched surface morphology by ensuring that the entire etching reaction is dissolution-restricted (i.e., by ensuring that the halogenation rate is much faster than the ligand-assisted dissolution rate). This can be achieved by the techniques described herein because the halogenation kinetics and dissolution kinetics can be independently controlled by adjusting the relative amounts of halogenating agents and ligands in the CMP slurry so that the halogenation rate of the ruthenium surface is greater than the dissolution rate of the ruthenium halide surface. Currently available oxidant-based etching chemicals lack this independent control.

[0040] In some embodiments, the CMP slurry described herein contains a halogenating agent but does not contain an oxide-forming oxidizing agent such as water or dissolved oxygen. In other embodiments, the CMP slurry may contain both a halogenating agent and an oxide-forming oxidizing agent. In one exemplary embodiment, the CMP slurry described above may further contain a predetermined amount of water or dissolved oxygen. When chlorination is carried out in the presence of an oxide-forming oxidizing agent such as water or dissolved oxygen, RuO x Cl yA ruthenium chloride (e.g., RuCl3) passivation layer containing seeds is formed on the ruthenium surface. x Cl y Since the seeds are generally more soluble than the ruthenium chloride passivation layer, RuO2 on the ruthenium surface x Cl y The presence of seeds increases the material removal rate achieved in the CMP process.

[0041] The CMP slurry described herein may also contain, in addition to the aforementioned liquid components, polishing media for mechanically polishing the ruthenium surface, such as silica, alumina, ceria, or other nanoparticles. This mechanical polishing increases the local temperature at higher locations on the wafer surface. This local heating plays a role in increasing the etching kinetics, which helps in the planarization of the wafer. Since the ligand exchange reaction used to solubilize RuCl3 is very sensitive to temperature, local heating occurring at higher locations is very effective in increasing the local etching rate in those regions.

[0042] This disclosure provides an improved CMP process, in addition to a novel CMP slurry, which planarizes a ruthenium surface using the CMP slurry chemicals disclosed herein. The CMP process disclosed herein can be used with a wide variety of CMP tools and systems. Figure 1 shows an embodiment of a CMP system 100, which includes a polishing pad 105 mounted on top of a rotatable platen 110 and a slurry dispenser 115 for distributing slurry 120 onto the top of the polishing pad 105. As the platen 110 rotates, the motion of the platen 110 distributes the slurry 120 onto the surface of the polishing pad 105. A wafer carrier 125 holds and positions a wafer 130 (e.g., a semiconductor substrate) and applies a downward force between the wafer surface and the polishing pad 105. The wafer carrier 125 can rotate along the platen 110 and move radially. A pad conditioner 135 is used to maintain pad flatness and surface quality. The techniques described herein include improved slurry chemicals as part of the chemically reactive portion of chemical mechanical material removal. As mentioned, Figure 1 shows one exemplary CMP system. It will be recognized by those skilled in the art that the techniques, methods, processes and slurry chemicals described herein may be used in a wide variety of CMP tools and systems, and are not limited to those shown in Figure 1.

[0043] Finally, this disclosure provides various methods utilizing the novel CMP slurry chemicals and CMP processes disclosed herein. Figure 2 shows one embodiment of a method utilizing the techniques described herein for planarizing the surface of a substrate or removing ruthenium from the surface of a substrate. The embodiment in Figure 2 is merely illustrative, and it will be understood that additional methods may utilize the techniques described herein. Furthermore, since the steps described are not intended to be exclusive, additional processing steps may be added to the method shown in Figure 2. Moreover, the order of the steps is not limited to the order shown in the figure, as different orders may occur and / or various steps may be performed in combination or simultaneously.

[0044] Figure 2 shows one embodiment of method 200 for removing ruthenium. Method 200 can generally begin by placing a substrate in a chemical mechanical polishing (CMP) system (in step 210). Figure 1 shows one embodiment of a CMP system (or CMP tool) in which the substrate may be placed in step 210. As described above and shown in Figure 1, the CMP system 100 may generally include a polishing pad 105 mounted on a rotatable platen 110, the polishing pad 105 being able to rotate and move across the substrate surface. In some embodiments, the substrate may include a ruthenium surface.

[0045] Next, Method 200 may include distributing the slurry onto a polishing pad (in step 220). As described above, the slurry may generally include a solvent, a halogenating agent that halogenates the ruthenium surface to form a ruthenium halide surface, a ligand that reacts with the ruthenium halide surface to dissolve it, and a catalyst that increases the rate of ligand exchange reaction with the ruthenium halide surface. In some embodiments, Method 200 may include controlling the relative amounts of halogenating agent and ligand in the slurry such that the halogenation rate of the ruthenium surface is greater than the dissolution rate of the ruthenium halide surface.

[0046] Next, method 200 may include polishing the ruthenium surface with a slurry until a predetermined amount of ruthenium is removed (in step 230).

[0047] Throughout this specification, the expression “one embodiment” means that certain features, structures, materials, or properties described in that embodiment are included in at least one embodiment of the present invention, but not that they are present in all embodiments. Therefore, the appearance of the phrase “in one embodiment” in various places throughout this specification does not necessarily refer to the same embodiment of the present invention. Furthermore, certain features, structures, materials, or properties may be combined in any suitable way in one or more embodiments. In other embodiments, various additional layers and / or structures may be included, and / or the features described may be omitted.

[0048] As used herein, the term “substrate” means and includes a base material or structure on which a material is formed. It will be understood that a substrate may include a single material, multiple layers of different materials, a single layer or multiple layers having regions of different materials or different structures inside, etc. These materials may include semiconductors, insulators, conductors, or combinations thereof. For example, a substrate may be a semiconductor substrate on which one or more layers, structures or regions are formed, a base semiconductor layer on a support structure, a metal electrode, or a semiconductor substrate. A substrate may be a conventional silicon substrate or another bulk substrate including a layer of semiconducting material. As used herein, the term “bulk substrate” means and includes not only silicon wafers but also silicon-on-sapphire ("SOS") substrates and silicon-on-glass ("SOG") substrates, silicon-on-insulator ("SOI") substrates, an epitaxial layer of silicon on a base semiconductor substrate, and other semiconductor or optoelectronic materials such as silicon germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide. The circuit board can be doped or not.

[0049] Systems and methods for planarizing the surface of a substrate are described in various embodiments. The substrate may include any material portion or structure of a device, in particular a semiconductor or other electronic device, and may be a base substrate structure such as a semiconductor substrate, or a layer on or covering the base substrate structure, such as a thin film. Thus, the substrate is not intended to be limited to any particular base structure, underlay or toplay, whether patterned or unpatterned, but rather to include any such layer or base structure, and any combination of layers and / or base structures.

[0050] Those skilled in the art will understand that various embodiments may be carried out without one or more of the specific details, or with other alternative and / or additional methods, materials, or components. In other examples, details of known structures, materials, or operations are not illustrated or described so as not to obscure the various embodiments of the present invention. Similarly, certain numbers, materials, and configurations are described for illustrative purposes to provide a complete understanding of the present invention. Nevertheless, the present invention may be carried out without specific details. Furthermore, it should be understood that the various embodiments shown in the figures are illustrative and not necessarily drawn to scale.

[0051] Upon consideration of this specification, further variations and alternative embodiments of the systems and methods described will become apparent to those skilled in the art. Therefore, it will be recognized that the systems and methods described are not limited by these exemplary configurations. It should be understood that the forms of systems and methods illustrated and described herein should be considered exemplary embodiments. Various modifications may be made to the implementations. Thus, while ruthenium CMP technology is described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of this disclosure. Accordingly, this specification and the drawings should be considered illustrative rather than restrictive, and such modifications are intended to be included within the scope of this disclosure. Furthermore, no benefit, advantage, or solution to a problem described herein with respect to a particular embodiment is intended to be construed as an important, necessary, or essential feature or element of any or all of the claims.

[0052] Those skilled in the art will understand that many modifications can be made to the operation of the technology described above while achieving the same objectives as the present invention. Such modifications are intended to be included within the scope of this disclosure. Therefore, the foregoing description of embodiments of the present invention is not intended to be limiting. Rather, any limitations on embodiments of the present invention are presented in the following claims.

Claims

1. A composition, Having a chemical mechanical polishing (CMP) slurry, The CMP slurry is Non-aqueous solvents and A halogenating agent that halogenates a ruthenium surface to form a halogenated ruthenium surface, wherein the halogenated ruthenium surface is insoluble in the non-aqueous solvent, and A ligand that reacts with the halogenated ruthenium surface to dissolve the halogenated ruthenium surface, A catalyst that increases the rate of ligand exchange reaction with the halogenated ruthenium surface, It has, The CMP slurry is a composition that does not contain an oxide-forming oxidizing agent.

2. The CMP slurry is non-aqueous, The composition according to claim 1, wherein the non-aqueous CMP slurry suppresses the hydrolysis of the halogenating agent.

3. The CMP slurry comprises abrasive particles, as described in claim 1.

4. The composition according to claim 1, wherein the relative amounts of the halogenating agent and the ligand in the CMP slurry provide a halogenation rate of the ruthenium surface that is greater than the rate of dissolution of the halogenated ruthenium surface.

5. By containing the halogenating agent in the CMP slurry and not containing the oxide-forming oxidizing agent, the CMP slurry contains Ru on the ruthenium surface. ３＋ The composition according to claim 1, which limits the oxidation state to

6. The composition according to claim 1, wherein the CMP slurry does not contain water, dissolved oxygen, or another oxide-forming oxidizing agent.

7. The halogenating agent reacts with the ruthenium surface to form a self-limiting ruthenium trichloride (RuCl ３ The composition according to claim 1, which forms a passivation layer.

8. The composition according to claim 1, wherein the halogenating agent comprises trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, or N-chlorosuccinimide.

9. The composition according to claim 1, wherein the non-aqueous solvent is ethyl acetate, acetone, acetonitrile, or chlorocarbon.

10. The halogenating agent is a chlorinating agent, The chlorinating agent reacts with the ruthenium surface to form a chlorinated ruthenium surface. The composition according to claim 1, wherein the ligand is reactive with respect to the chlorinated ruthenium surface.

11. The halogenating agent is a fluorinating agent, The fluorinating agent reacts with the ruthenium surface to form a fluorinated ruthenium surface. The composition according to claim 1, wherein the ligand is reactive with respect to the fluorinated ruthenium surface.

12. The halogenating agent is a brominating agent, The brominating agent reacts with the ruthenium surface to form a brominated ruthenium surface. The composition according to claim 1, wherein the ligand is reactive with respect to the ruthenium brominated surface.

13. The composition according to claim 1, wherein the ligand comprises ethylenediaminetetraacetic acid (EDTA), acetylacetone (ACAC), iminodiacetic acid (IDA), or diethylenetriaminepentaacetic acid (DTPA).

14. The composition according to claim 1, wherein the catalyst is a base.

15. The aforementioned bases are potassium hydroxide (KOH), sodium hydroxide (NaOH), and ammonium hydroxide (NH₃). ４ OH), or tetramethylammonium hydroxide ((CH) ３ ) ４ The composition according to claim 14, comprising NOx.

16. The composition according to claim 1, wherein the ligand reacts with the halogenated ruthenium surface, making the halogenated ruthenium surface soluble via the ligand exchange reaction, and providing ligand-assisted reactive dissolution of the halogenated ruthenium surface.

17. The halogenating agent in the non-aqueous solvent reacts with the ruthenium surface to form a self-limiting ruthenium halide passivation layer. The ligand is a composition according to claim 1, which converts a CMP process using the CMP slurry from a self-limiting surface passivation process to a continuous etching process.

18. The catalyst is a base, The composition according to claim 17, wherein the base deprotonates the ligand to increase the rate of the ligand exchange reaction with the halogenated ruthenium surface, and continuously etches the halogenated ruthenium surface.

19. A method for removing ruthenium, the method is A step of placing a substrate in a chemical mechanical polishing (CMP) system, wherein the CMP system has a polishing pad mounted on a rotatable platen, the polishing pad is rotatable and can move across the surface of the substrate, and the substrate includes a ruthenium surface, The step of distributing slurry onto the polishing pad, wherein the slurry is Non-aqueous solvents and A halogenating agent that halogenates the ruthenium surface to form a halogenated ruthenium surface, wherein the halogenated ruthenium surface is insoluble in the non-aqueous solvent, A ligand that reacts with the halogenated ruthenium surface to dissolve the halogenated ruthenium surface, A catalyst that increases the rate of ligand exchange reaction with the halogenated ruthenium surface, It has, The slurry does not contain an oxide-forming oxidizing agent, and the steps are as follows: The steps include polishing the ruthenium surface with the slurry until a predetermined amount of ruthenium is removed, A method having

20. Furthermore, the process includes a step of controlling the relative amounts of the halogenating agent and the ligand in the slurry. The method according to claim 19, wherein the rate of halogenation of the ruthenium surface is greater than the rate of dissolution of the halogenated ruthenium surface.

21. The halogenating agent includes a chlorinating agent that reacts with the ruthenium surface to form a chlorinated ruthenium surface, The method according to claim 20, wherein the ligand reacts with the ruthenium chloride surface to dissolve the ruthenium chloride surface.

22. The halogenating agent includes a chlorinating agent that reacts with the ruthenium surface to form a chlorinated ruthenium surface, The method according to claim 19, wherein the ligand reacts with the ruthenium chloride surface to dissolve the ruthenium chloride surface.

23. The method according to claim 19, wherein the catalyst is a base.

24. The aforementioned bases are potassium hydroxide (KOH), sodium hydroxide (NaOH), and ammonium hydroxide (NH₃). ４ OH), or tetramethylammonium hydroxide ((CH) ３ ) ４ The method according to claim 23, comprising NOx.

25. The slurry is non-aqueous, The method according to claim 19, wherein the non-aqueous slurry suppresses the hydrolysis of the halogenating agent.

26. The method according to claim 19, wherein the slurry contains abrasive particles.

27. By containing the halogenating agent in the slurry and not containing the oxide-forming oxidizing agent, the slurry limits the oxidation state of Ru on the ruthenium surface ３＋ The method according to claim 19, which limits the oxidation state to

28. The method according to claim 19, wherein the slurry does not contain water, dissolved oxygen, or another oxide-forming oxidizing agent.

29. The halogenating agent reacts with the ruthenium surface to form a self-limiting ruthenium trichloride (RuCl ３ The method according to claim 19, wherein a passivation layer is formed.

30. The method according to claim 19, wherein the halogenating agent comprises trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, or N-chlorosuccinimide.

31. The method according to claim 19, wherein the non-aqueous solvent is ethyl acetate, acetone, acetonitrile, or chlorocarbon.

32. The halogenating agent is a fluorinating agent, The fluorinating agent reacts with the ruthenium surface to form a fluorinated ruthenium surface. The method according to claim 19, wherein the ligand is reactive with respect to the fluorinated ruthenium surface.

33. The halogenating agent is a brominating agent, The brominating agent reacts with the ruthenium surface to form a brominated ruthenium surface. The method according to claim 19, wherein the ligand is reactive with respect to the ruthenium brominated surface.

34. The method according to claim 19, wherein the ligand comprises ethylenediaminetetraacetic acid (EDTA), acetylacetone (ACAC), iminodiacetic acid (IDA), or diethylenetriaminepentaacetic acid (DTPA).

35. The method according to claim 19, wherein the ligand reacts with the halogenated ruthenium surface, making the halogenated ruthenium surface soluble via the ligand exchange reaction, and providing ligand-assisted reactive dissolution of the halogenated ruthenium surface.

36. The method according to claim 35, further comprising the step of controlling the relative amounts of the halogenating agent and the ligand in the slurry such that the halogenation rate of the ruthenium surface is greater than the dissolution rate of the halogenated ruthenium surface.

37. The halogenating agent includes a chlorinating agent, The chlorinating agent reacts with the ruthenium surface to form a chlorinated ruthenium surface. The method according to claim 36, wherein the ligand reacts with the ruthenium chloride surface to dissolve the ruthenium chloride surface.

38. The halogenating agent in the non-aqueous solvent reacts with the ruthenium surface to form a self-limiting ruthenium halide passivation layer. The method according to claim 19, wherein the ligand converts the method for removing ruthenium from a self-limiting surface passivation to a continuous etching process.

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