Multi-Layered Hard Mask for Semiconductor Pattern Transfer
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Solution Overview
Problem
The miniaturization of semiconductor devices requires more precise and efficient techniques for preparing fine patterns in target layers, as existing methods with single-layered hard masks often result in damaged patterns and poor transfer due to multiple etching processes.
Innovation Solution
A multi-layered hard mask layer is formed over the target layer, comprising different materials for each layer, allowing for precise patterning and transfer of patterns through multiple photolithography processes, with the first and second hard mask layers forming specific patterns and the third layer being etched to expose the target layer for subsequent etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-layered hard mask layer is used with multiple etching processes, then the etching can be completed, but the pattern becomes damaged and transfer quality deteriorates
Solution Approach 1:
The hard mask layer is divided into three distinct layers (first, second, and third hard mask layers) with different materials. Each layer serves a specific function in the etching process, allowing selective removal of materials without damaging the underlying pattern. This segmentation enables precise control over the etching process while maintaining pattern integrity.
Solution Approach 2:
The multi-layered hard mask structure uses composite materials where each layer is made of a different material optimized for specific etching conditions. This allows each layer to resist etching at appropriate rates, preventing pattern damage while enabling complete material removal through the stack.
2Quantity of substance
If multiple etching processes are used to remove different materials, then complete material removal is achieved, but the process complexity increases
Solution Approach 1:
The multi-layered hard mask structure is prepared in advance with specific material compositions and thicknesses designed to enable selective etching. The first, second, and third layers are configured so that etching can proceed through them in a controlled sequence, with each layer being removed at the appropriate stage of the process.
Solution Approach 2:
Each hard mask layer is designed with specific material properties and thickness parameters that allow selective removal. By controlling etching parameters and using materials with different etching resistances, the process can selectively remove materials without requiring overly complex process steps.
3Manufacturing precision
If the hard mask layer is made thinner to achieve finer patterns, then pattern density increases, but the mask strength and pattern integrity deteriorate
Solution Approach 1:
Instead of reducing the thickness of a single hard mask layer, the solution adds vertical dimensionality by stacking multiple hard mask layers. This multi-layer structure provides the necessary mechanical strength and pattern integrity while allowing each individual layer to be thin enough to enable fine pattern formation.
Solution Approach 2:
The hard mask function is segmented across three layers, distributing the mechanical load and protective function across multiple thin layers rather than requiring one thick layer. This allows fine pattern resolution while maintaining overall mask strength through the stacked structure.
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 method enables precise and effective pattern transfer to the target layer, increasing pattern density and maintaining shape integrity, unlike single-layered hard masks which suffer from pattern damage and poor transfer.
Implementation Method 1
The photoresist layer is exposed to UV light and developed to form a patterned photoresist layer
Implementation Method 2
The exposed photoresist layer and the exposed sacrificial layer are etched
Data Source
AI summary
A method for preparing a patterned target layer is provided. A target layer is formed over a substrate. A multi-layered hard mask layer is formed over the target layer. The multi-layered hard mask layer includes a first hard mask layer over the target layer, a second hard mask layer between the target layer and the first hard mask layer, and a third hard mask layer between the target layer and the second hard mask layer, wherein a material of the second hard mask layer is different from a material of the first hard mask layer and a material of the third hard mask layer. The multi-layered hard mask layer is used as a hard mask layer to prepare a fine pattern on the target layer.