Selective Hardmask Etching for Thinner Photoresist Patterning
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Solution Overview
Problem
As semiconductor features and critical dimensions shrink, larger aspect ratios of photoresist and mask thicknesses lead to structural instabilities during patterning, resulting in lower yields and potential defects in the hardmask material.
Innovation Solution
The use of hydrogen-and-fluorine-containing plasma effluents, generated from precursors like HF gas, to etch silicon-containing hardmask materials with a selectivity greater than or about 10 relative to the photoresist material, allowing for thinner photoresist layers and improved patterning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the combined thickness of photoresist and masks is increased to maintain structural stability, then structural stability is improved, but the aspect ratio to critical dimensions increases leading to lower yields
Solution Approach 1:
The patent changes the chemical composition and etching parameters by using hydrogen-and-fluorine-containing plasma effluents with a volumetric ratio greater than 50:1, achieving high selectivity (greater than or about 10) for etching silicon-containing hardmask material while minimizing photoresist etching. This enables thinner photoresist layers without compromising structural stability.
Solution Approach 2:
The patent employs a composite material system consisting of silicon-containing hardmask material combined with photoresist material, where the silicon-containing material provides the necessary structural stability while the photoresist enables patterning. The high selectivity etching allows this composite structure to function effectively at reduced thicknesses.
2Manufacturing precision
If the combined thickness of photoresist and masks is decreased to lower aspect ratios, then manufacturing precision is improved, but structural stability deteriorates
Solution Approach 1:
The patent modifies the etching process parameters by using hydrogen-and-fluorine-containing plasma with a volumetric ratio greater than 50:1, achieving high selectivity (greater than or about 10) that allows thinner photoresist layers to be used while maintaining sufficient structural stability during patterning.
3Speed
If conventional etchants are used that etch mask material effectively, then mask etching speed is improved, but photoresist is significantly etched requiring larger thickness
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using hydrogen-and-fluorine-containing plasma effluents, achieving high selectivity (greater than or about 10) for silicon-containing hardmask material. This allows effective mask etching while minimizing photoresist consumption, enabling thinner photoresist layers.
Solution Approach 2:
The patent introduces hydrogen-and-fluorine-containing plasma as an intermediary etching medium that selectively reacts with silicon-containing hardmask material while having minimal effect on photoresist, enabling differential etching with high 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 high-selectivity etching of silicon-containing hardmask materials, reducing structural instability and enhancing the quality of semiconductor devices by allowing for thinner photoresist layers and precise EUV patterning.
Implementation Method 1
contacting a silicon-containing hardmask material and a photoresist material with the plasma effluents in a processing region of a semiconductor processing chamber
Implementation Method 2
etching the photoresist material with the plasma effluents; and while etching the photoresist material, etching the silicon-containing hardmask material with the plasma effluents
Data Source
AI summary
Methods of semiconductor processing may include forming plasma effluents of a hydrogen-and-fluorine-containing precursor. The plasma effluents may then contact a silicon-containing hardmask material and a photoresist material. The silicon-containing hardmask material can overlay an organic material overlaying a substrate in a processing region of a semiconductor processing chamber. Etching the silicon-containing hardmask material with the plasma effluents while the photoresist material with the plasma effluents. The silicon-containing hardmask material can be etched at a selectivity greater than or about 10 relative to the photoresist material. A temperature in the processing region can be maintained at about −20° C. or less.