Ruthenium Carbide Hard Mask for DRAM Capacitor Mold Patterning
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Solution Overview
Problem
Current hard mask materials, such as boron-doped silicon, lack sufficient etch selectivity for advanced semiconductor devices like NAND and DRAM, particularly at the N+2 technology node, where further improvements in capacitor mold patterning are needed to maintain miniaturization and increase integration density.
Innovation Solution
A ruthenium carbide hard mask is deposited on a capacitor mold, with a hard mask oxide formed on top, and patterned using an etchant plasma containing oxygen, chlorine, and carbonyl sulfide, allowing for improved selectivity and patterning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If boron-doped silicon is used as hard mask material, then the patterning process is simple, but the etch selectivity is insufficient for advanced nodes
Solution Approach 1:
The patent uses a composite material system consisting of ruthenium carbide hard mask deposited on capacitor mold with silicon oxide and silicon carbon nitride layers. This composite structure provides the necessary etch selectivity for advanced nodes while maintaining a manageable patterning process through the coordinated interaction of multiple material layers with different etch resistance properties.
Solution Approach 2:
The patent changes the material parameter from boron-doped silicon to ruthenium carbide, which has superior etch selectivity characteristics. The ruthenium carbide layer with specific thickness and composition parameters enables differentiated etching rates against surrounding materials, solving the selectivity deficiency of conventional boron-doped silicon at advanced technology nodes.
2Productivity
If capacitor mold dimensions are miniaturized, then integration density increases, but manufacturing precision requirements increase
Solution Approach 1:
The multi-layer composite structure of capacitor mold including silicon oxide base layer, silicon carbon nitride intermediate layer, and ruthenium carbide hard mask top layer provides differentiated etch selectivity at each interface. This enables precise control of feature placement and dimensional accuracy during miniaturization, allowing higher integration density without sacrificing manufacturing precision.
Solution Approach 2:
The capacitor mold is segmented into multiple functional layers with distinct etch selectivity characteristics. The silicon oxide layer provides structural support, the silicon carbon nitride layer offers intermediate etch resistance, and the ruthenium carbide hard mask provides the most selective etching barrier. This segmentation enables step-by-step precise patterning of submicron features.
3Manufacturing precision
If etch selectivity is improved, then patterning precision increases, but process complexity increases
Solution Approach 1:
The patent employs a composite material stack where each layer contributes to overall etch selectivity in a coordinated manner. The ruthenium carbide hard mask on silicon carbon nitride on silicon oxide creates a hierarchical selectivity system that achieves high patterning precision while managing process complexity through the inherent material property differences rather than complex process sequencing.
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
The ruthenium carbide hard mask provides enhanced etch selectivity and patterning capabilities, enabling more precise formation of submicron features and increased integration density in semiconductor devices, addressing the limitations of existing boron-doped silicon hard masks.
Implementation Method 1
The pattern of the photoresist is transferred to the anti-reflective coating, the hard mask oxide and the ruthenium carbide hard mask by exposing the substrate to an etchant plasma
Implementation Method 2
The ability to remove the hard mask material without affecting other surface features (also referred to as etch selectivity) is a useful feature
Implementation Method 3
A ruthenium carbide hard mask is deposited on a capacitor mold formed on a substrate
Data Source
AI summary
Methods of forming electronic devices and film stacks comprising depositing a ruthenium carbide hard mask on a capacitor mold formed on a substrate. A hard mask oxide and patterned photoresist are formed, and the pattern of the patterned photoresist are transferred into the ruthenium carbide hard mask. Film stacks comprising the ruthenium carbide hard mask on the capacitor mold are also described.