Atomic Layer Etching of Ruthenium Films via Halogen and Carbon-Oxygen Gas Cycles
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Solution Overview
Problem
Existing methods for etching metals, such as ruthenium films, often result in damage to desired regions due to the use of plasma, which is not precise enough for atomic-level control, especially when removing trace amounts of metals from undesired areas.
Innovation Solution
The method employs an atomic layer etching (ALE) process that modifies the metal surface with a halogen-containing gas and then removes the halide-containing surface layer using a gas containing carbon and oxygen, allowing for precise etching without plasma, thereby minimizing damage to the desired metal film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma is used to etch metal films, then etching can be performed, but the metal film in desired regions is damaged due to lack of atomic-level control
Solution Approach 1:
The etching process is divided into multiple sequential steps: (a) modifying the metal surface with a halogen-containing gas to form a halide-containing surface layer, and (b) removing the halide-containing surface layer with a gas containing carbon and oxygen. This segmentation allows precise control at the atomic level, enabling selective etching of trace metal amounts without damaging the metal film in desired regions.
Solution Approach 2:
The patent changes the chemical parameters of the etching process by using specific gas combinations (halogen-containing gas followed by carbon and oxygen-containing gas) instead of plasma. This parameter change enables atomic-level control and eliminates the harmful effects of plasma on the metal film while maintaining etching effectiveness.
2Measurement precision
If plasma is used for etching, then metal removal can be achieved, but atomic-level control is insufficient for removing trace amounts of metals
Solution Approach 1:
The etching process is segmented into distinct modification and removal steps, each with specific gas conditions. Step (a) modifies the metal surface with halogen-containing gas, and step (b) removes the modified layer with carbon and oxygen-containing gas. This segmentation provides atomic-level control necessary for removing trace amounts of metals precisely.
Solution Approach 2:
The patent employs continuous repetition of the modification and removal steps to achieve precise removal of trace metals. By continuously cycling through these controlled steps, the process maintains atomic-level precision while effectively removing minimal amounts of metal from undesired areas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high-precision etching of trace metal amounts down to the atomic level, ensuring minimal damage to the metal film in desired regions while effectively removing metal from undesired areas, thus optimizing the selective formation of metal films.
Implementation Method 1
modifying a surface layer of the metal into a halide-containing surface layer by exposing the metal to a halogen-containing gas
Implementation Method 2
removing the halide-containing surface layer by exposing the modified halide-containing surface layer to a gas containing carbon (C) and oxygen (O)
Data Source
AI summary
Provided is a method for etching a metal on a substrate, the etching method including (a) a step for exposing the metal to a halogen-containing gas and modifying a surface layer of the metal to be a halide-containing surface layer, (b) a step for exposing the halide-containing surface layer to a gas that contains carbon (C) and oxygen (O) and removing the halide-containing surface layer, and (c) a step for repeating the (a) step and the (b) step in the stated order.