Remote Plasma Carbon Hardmask Etching Selectivity
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Solution Overview
Problem
Current dry etch processes struggle to selectively remove carbon hardmask materials from patterned semiconductor substrates without damaging adjacent materials, such as silicon, silicon nitride, and silicon oxide, due to lack of selectivity and potential for physical disturbance.
Innovation Solution
A remote plasma etching method using a combination of fluorine-containing and oxygen-containing precursors, such as nitrogen trifluoride and oxygen, is employed to create plasma effluents that selectively etch carbon hardmask materials at a higher rate than silicon, silicon nitride, silicon carbide, and silicon oxide, with an ion suppressor ensuring minimal ion damage and precise control over etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etch processes are used to remove carbon hardmask material, then material removal is achieved, but selectivity relative to silicon-based materials is insufficient and physical disturbance occurs
Solution Approach 1:
The patent changes the chemical parameters of the etch process by using a dual-precursor system (fluorine-containing and oxygen-containing precursors) with remote plasma excitation. This creates a chemically selective environment where carbon etching is dramatically enhanced while silicon-based materials remain protected, achieving up to 75:1 selectivity without physical disturbance
Solution Approach 2:
The patent replaces conventional plasma etching mechanisms that rely on ion bombardment and physical sputtering with a chemically-driven remote plasma process. The ion suppressor removes ions from the plasma, eliminating mechanical/physical disturbance while maintaining etching capability through purely chemical reactions between plasma effluents and carbon material
2Productivity
If high ion flux plasma is used to increase etch rate, then productivity improves, but damage to patterned structures increases
Solution Approach 1:
The patent extracts ions from the plasma using an ion suppressor component positioned between the plasma generation region and the substrate. This allows the beneficial reactive species to reach the substrate for etching while removing the harmful ions that would cause damage to patterned structures, maintaining high etch rates without ion damage
Solution Approach 2:
The ion suppressor acts as an intermediary element that selectively filters the plasma composition. It allows neutral reactive species to pass through while blocking ions, serving as a mediator between the high-energy plasma source and the sensitive patterned substrate
3Manufacturing precision
If remote plasma with fluorine and oxygen precursors is used, then selectivity reaches up to 75:1, but process complexity increases
Solution Approach 1:
The patent segments the etch process into distinct functional zones: a plasma generation region where precursors are excited, an ion suppression region where harmful ions are removed, and a substrate processing region where selective etching occurs. This segmentation allows each zone to be optimized independently, achieving high selectivity while managing complexity through functional separation
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 achieves selective etching of carbon hardmask materials with high selectivity (up to 75:1) relative to silicon-based materials, minimizing damage and allowing for precise pattern transfer in semiconductor manufacturing, while maintaining low substrate temperatures and controlled plasma conditions.
Implementation Method 1
A remote plasma etching method using a combination of fluorine-containing and oxygen-containing precursors, such as nitrogen trifluoride and oxygen, is employed to create plasma effluents that selectively etch carbon hardmask materials
Implementation Method 2
The remote plasma excites a fluorine-containing precursor and an oxygen-containing precursor, the plasma effluents created are flowed into a substrate processing region
Implementation Method 3
with an ion suppressor ensuring minimal ion damage and precise control over etch rates
Implementation Method 4
Chemical etching is used for a variety of purposes including transferring a pattern in photoresist into underlying layers
Data Source
AI summary
A method of etching carbon films on patterned heterogeneous structures is described and includes a gas phase etch using remote plasma excitation. The remote plasma excites a fluorine-containing precursor and an oxygen-containing precursor, the plasma effluents created are flowed into a substrate processing region. The plasma effluents etch the carbon film more rapidly than silicon, silicon nitride, silicon carbide, silicon carbon nitride and silicon oxide.