Selective Etching via Fluorocarbon Precursor and Inert Plasma
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Solution Overview
Problem
Current substrate processing methods lack a selective etching process that effectively differentiates between various regions on a substrate surface, such as silicon nitride and silicon oxide, leading to inefficient etching and potential particle generation.
Innovation Solution
A substrate processing method involving the supply of a precursor containing halogen and carbon, which forms a chemical bond specifically with the first region, followed by exposure to a plasma of an inert gas, allowing for selective etching of the first region while minimizing etching of the second region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etching method is used, then the etching process can be performed, but selective etching between different regions (silicon nitride and silicon oxide) is not achieved, leading to unwanted etching of non-target regions
Solution Approach 1:
The patent applies preliminary action by forming a deposit containing fluorocarbon on the substrate surface before the etching step. This deposit is then selectively removed in the target region through plasma treatment, creating a patterned structure that enables selective etching. The preliminary deposition of fluorocarbon compound prepares the surface for subsequent selective removal, achieving region-specific etching without affecting non-target areas.
Solution Approach 2:
The patent utilizes parameter changes by controlling the plasma treatment conditions (gas composition, power, temperature) to selectively remove the fluorocarbon deposit from specific regions while leaving other regions intact. By adjusting plasma parameters such as using CF4 or C4F8 gas and controlling RF power, the process achieves selective etching based on the chemical and physical property differences between target and non-target regions.
2Productivity
If conventional plasma etching is used, then etching can be performed, but it causes particle generation and contamination on the substrate surface
Solution Approach 1:
The patent introduces an intermediary substance (fluorocarbon compound) that mediates between the plasma etching process and the substrate surface. The fluorocarbon deposit acts as a protective layer on non-target regions while allowing controlled removal on target regions. This intermediary material enables the etching process to proceed efficiently on intended areas while preventing particle generation and contamination on protected areas.
Solution Approach 2:
The patent employs an inert fluorocarbon atmosphere during the deposition step, creating a controlled chemical environment that allows selective formation of protective deposits. The use of fluorocarbon compounds in a controlled atmosphere enables precise control over where etching occurs, reducing unwanted particle generation and maintaining substrate cleanliness in non-target regions.
3Manufacturing precision
If selective etching is not implemented, then the process is simpler, but etching accuracy and contamination control are compromised
Solution Approach 1:
The patent achieves selective etching with controlled complexity by implementing a straightforward preliminary deposition step followed by plasma treatment. The process sequence of depositing fluorocarbon compound and then performing selective plasma etching provides a clear, manageable workflow that balances manufacturing precision with process simplicity, avoiding overly complex multi-step procedures while achieving the desired selectivity.
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 a stable and controlled etching process that selectively targets the first region, preventing unwanted etching of the second region and reducing particle generation, thereby improving etching accuracy and reducing contamination.
Implementation Method 1
supplying a precursor to the surface of the substrate, the precursor including at least both a halogen and carbon and being configured to form a first chemical bond in the first region
Implementation Method 2
exposing the surface of the substrate to a plasma of an inert gas
Data Source
AI summary
A substrate processing method including: a) providing a substrate having a first region on a surface; b) supplying a precursor to the surface of the substrate, the precursor including at least both a halogen and carbon and being configured to form a first chemical bond in the first region; and c) exposing the surface of the substrate to a plasma of an inert gas.