Tokyo Electron Limited

The University of Texas System

Tokyo Electron Limi Ted

Paul Abel

Jacques Faguet

Omid Zandi

Mengistie Debasu

Adam Heller

Mitsuaki Iwashita

Ryuichi Asako

Tamotsu Morimoto

Antonio Luis Pacheco Rotondaro

Tetsuya Sakazaki

Takeo Nakano

Dipak Aryal

Arkalgud Sitaram

Christopher Netzband

Charles Buddie Mullins

Tulashi Dahal

Kyle C Klavetter

Embodiments of processes and methods that provide selective etching of silicon nitride are disclosed herein. More specifically, new processes, methods and etch chemistries are provided to selectively etch silicon nitride layers formed on a substrate, while protecting silicon oxide layers formed on the same substrate. In the method embodiments, a substrate having a silicon nitride (SiN) layer and a silicon oxide layer formed on the same substrate is exposed to an alkylating agent, which reacts with the amine groups on the exposed SiN surfaces to form an alkylated surface layer on the SiN layer. The substrate is exposed to a fluorinating agent to remove the alkylated surface layer and selectively etch the SiN layer without significantly etching the silicon oxide layer. The disclosed methods can be used to selectively etch silicon nitride over silicon oxide using a wet or dry process.

Method to selectively etch silicon nitride to silicon oxide using surface alkylation

Systems and methods are provided for etching molybdenum in a wet ALE process. The methods disclosed herein use a wide variety of techniques and wet etch chemistries to oxidize a molybdenum surface and form a self-limiting, molybdenum oxide passivation layer in a surface modification step of the wet ALE process. For example, the methods use: (a) ultra-violet (UV) photolysis of peroxide oxidizers to create oxidizing radicals, which limit oxidation of the molybdenum surface and provide quasi-self-limiting oxidation behavior, (b) steric hinderance of oxidizers having large reactant molecules to achieve better self-limiting oxidation behavior, and/or (c) ligand-assisted oxidation to change the surface chemistry of the molybdenum oxide passivation layer and ensure self-limiting oxidation behavior. After forming the molybdenum oxide passivation layer using one or more of the oxidation techniques disclosed herein, the passivation layer is selectively removed in a dissolution step of the wet ALE process to etch the molybdenum surface.

Methods for wet atomic layer etching of molybdenum

The present disclosure provides a hybrid atomic layer etching (ALE) process that combines a gas-phase surface modification step with a liquid-phase dissolution step for etching an exposed material on a substrate disposed within a process chamber. In the hybrid ALE process disclosed herein, a gas-phase reactant is used to modify an exposed surface of the material to create a modified surface layer, and one or more liquid-phase reactants are used to selectively dissolve the modified surface layer without dissolving the material underlying the modified surface layer. Once the modified surface layer is selectively dissolved, the substrate may be dried and the gas-phase surface modification and liquid-phase dissolution steps may be repeated for one or more ALE cycles until a desired amount of the material is etched.

Methods for etching a substrate using a hybrid wet atomic layer etching process

Embodiments of improved methods and processes are provided for patterning a semiconductor substrate using direct self-assembly (DSA) of ionic liquid crystals (ILCs). In the disclosed embodiments, an ILC solution comprising ILCs is deposited on a variety of substrate surfaces. An upper surface of the ILC solution is exposed to a gas phase, non-polar solvent (such as, e.g., hexane gas). The gas phase, non-polar solvent provides an ambient environment that promotes self-assembly of the ILCs into vertically layered ILC structures.

Methods for forming vertically layered ionic liquid crystal (ILC) structures on a semiconductor substrate

The present disclosure provides improved wet etch processes and methods for etching noble metals. More specifically, the present disclosure provides various embodiments of wet etch processes and methods that utilize new etch chemistries for etching noble metals, such as ruthenium (Ru), gold (Au), platinum (Pt) and iridium (Ir), in a wet etch process. In general, the disclosed embodiments expose a noble metal surface to a first etch solution to chemically modify the noble metal surface and form a noble metal salt passivation layer, which can then be selectively dissolved in a second etch solution to etch the noble metal surface.

Methods for wet etching of noble metals

The present disclosure provides a system for etching an exposed material on a substrate disposed within a process chamber using a hybrid atomic layer etching (ALE) process that combines a gas-phase surface modification step with a liquid-phase dissolution step within the same process chamber. In the hybrid ALE process disclosed herein, a gas-phase reactant is used to modify an exposed surface of the material to create a modified surface layer, and one or more liquid-phase reactants are used to selectively dissolve the modified surface layer without dissolving the material underlying the modified surface layer. Once the modified surface layer is selectively dissolved, the substrate may be dried and the gas-phase surface modification and liquid-phase dissolution steps may be repeated for one or more ALE cycles until a desired amount of the material is etched.

Systems for etching a substrate using a hybrid wet atomic layer etching process

The present disclosure provides new processes and methods to pre-treat metal surfaces in the back end of line (BEOL) fabrication of integrated circuits (ICs). More specifically, the present disclosure provides selective, self-limiting processes and methods for stripping native oxide surface layers that may form on exposed metal surfaces during processing of ICs. The processes and methods disclosed herein utilize the fundamental concepts of metal complexation to provide a novel solution, which enables native oxide surface layers to be selectively removed from exposed metal films in a self-limiting manner. In particular, the disclosed processes and methods use complexing agents (e.g., ligands) to selectively dissolve native oxide surface layers, without significantly etching or removing the underlying metal film.

Methods for selective removal of surface oxides on metal films

The present disclosure provides a new corrosion control chemistry for use in ruthenium (Ru) chemical-mechanical polishing (CMP) processes. More specifically, the present disclosure provides an improved CMP slurry chemistry and CMP process for planarizing a ruthenium surface. In the CMP process disclosed herein, a ruthenium surface (e.g., a post-etch ruthenium surface) is exposed to a CMP slurry containing a halogenation reagent, which reacts with the ruthenium surface to create a halogenated ruthenium surface, and a ligand for ligand-assisted reactive dissolution of the halogenated ruthenium surface. Relative amounts of the halogenation agent and the ligand can be controlled in the CMP slurry, so as to provide a diffusion-limited etch process that improves pos-etch surface morphology, while providing high material removal rates.

Ruthenium CMP chemistry based on halogenation

The present disclosure provides various embodiments of an improved wet atomic layer etching (ALE) process. More specifically, the present disclosure provides various embodiments of methods that improve a wet ALE process by providing a dynamic ALE cycle timing schedule that balances throughput and etch rate with post-etch surface roughness. As described in more detail below, the methods disclosed herein may adjust the purge timing between ALE cycles and/or between individual surface modification and selective dissolution steps to provide a desired throughput, etch rate and/or post-etch surface roughness in a wet ALE process.

Dynamically adjusted purge timing in wet atomic layer etching

The present disclosure provides a new wet atomic layer etch (ALE) process for etching copper. More specifically, the present disclosure provides various embodiments of methods that utilize new etch chemistries for etching copper in a wet ALE process. By utilizing the new etch chemistries disclosed herein within a wet ALE process, the present disclosure provides a highly selective etch of copper with monolayer precision.

Methods for wet atomic layer etching of copper

The present disclosure provides a new wet atomic layer etch (ALE) process for etching ruthenium. More specifically, the present disclosure provides various embodiments of methods that utilize new etch chemistries for etching ruthenium in a wet ALE process. Unlike conventional etch processes for ruthenium, the wet ALE process described herein for etching ruthenium is metal-free, cost-effective and improves surface roughness during etching.

Methods for wet atomic layer etching of ruthenium

A processing system and platform for improving both the microscopic and macroscopic uniformity of materials during etching is disclosed herein. These improvements may be accomplished through the formation and dissolution of thin, self-limiting layers on the material surface by the use of wet atomic layer etching (ALE) techniques. For etching of polycrystalline materials, these self-limiting reactions can be used to prevent this roughening of the surface during etching. Thus, as disclosed herein, a wet ALE process uses sequential, self-limiting reactions to first modify the surface layer of a material and then selectively remove the modified layer.

Processing system and platform for wet atomic layer etching using self-limiting and solubility-limited reactions

A method for improving both the microscopic and macroscopic uniformity of materials during etching is disclosed herein. These improvements may be accomplished through the formation and dissolution of thin, self-limiting layers on the material surface by the use of wet atomic layer etching (ALE) techniques. For etching of polycrystalline materials, these self-limiting reactions can be used to prevent this roughening of the surface during etching. Thus, as disclosed herein, a wet ALE process uses sequential, self-limiting reactions to first modify the surface layer of a material and then selectively remove the modified layer.

Wet atomic layer etching using self-limiting and solubility-limited reactions

A method and a system for etching of semiconductor substrates, and particularly, wet etching of wafers. The etch rate of liquid solutions applied on the wafer is adjusted by irradiating the liquid solutions with spatially varied light intensity. Photo-reactive agents are added to the liquid solutions, the agents including photo acids, photo bases and photo-oxidizers. Illumination of the photo-reactive agents causes increase/decrease of the pH value and oxidation potential value of the liquid solutions.

Growing community of inventors

Austin, TX, United States of America

Paul Abel