TiO2-SiO2 Laminated Layer Crystallization Suppression
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Solution Overview
Problem
The thin SiO2 layer used in semiconductor devices exhibits poor mechanical strength and insulating properties, leading to defects such as non-uniform spacing and width in patterning processes, while TiO2 layers crystallize at thicknesses above 50 nm, compromising their insulating characteristics and causing device failures.
Innovation Solution
A laminated layer comprising TiO2 and SiO2 is formed using plasma-enhanced atomic layer deposition, with a cycle ratio of TiO2 to SiO2 layer formation below 20:1, and a post-treatment is applied to maintain a non-crystalline structure, suppressing crystallization and enhancing mechanical strength and insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a thin SiO2 layer is used to meet narrow line width requirements, then the device integration density is improved, but the mechanical strength and insulating properties deteriorate
Solution Approach 1:
The patent applies composite materials by forming a laminated structure consisting of multiple thin layers (TiO2, SiO2, TiN, SiN, or TaN) deposited in alternating cycles. This composite structure provides both the thin profile needed for narrow line widths and the enhanced mechanical strength through the combined properties of different materials, resolving the contradiction between thinness and strength.
2Reliability
If a TiO2 layer is used to improve insulating characteristics and mechanical strength, then the dielectric constant is improved, but crystallization occurs at thicknesses above 50 nm causing device failure
Solution Approach 1:
The patent segments the TiO2 layer into multiple thin sub-layers separated by other material layers (SiO2, TiN, SiN, or TaN). Each TiO2 sub-layer is thinner than the 50 nm crystallization threshold, and the intervening layers act as barriers to crystal growth, preventing crystallization while maintaining the high dielectric constant and mechanical strength benefits of TiO2.
Solution Approach 2:
The patent changes the thickness parameter of TiO2 layers from a single thick layer (>50 nm) to multiple thin layers (<50 nm each), fundamentally altering the structural parameter to prevent crystallization. This parameter change maintains the desired electrical and mechanical properties while avoiding the harmful crystalline phase transition.
3Strength
If the TiO2 layer thickness is increased to improve mechanical strength, then the film strength is improved, but crystal bumps form causing defects in subsequent etching processes
Solution Approach 1:
The patent creates a composite laminated structure where TiO2 layers providing mechanical strength are combined with other material layers. This composite approach achieves the necessary film strength through the combined structural integrity of multiple layers rather than relying on a single thick TiO2 layer, thereby preventing crystal bump formation while maintaining strength.
Solution Approach 2:
The patent segments the thick TiO2 layer into multiple thin alternating layers with other materials. This segmentation prevents the formation of crystal bumps by keeping each TiO2 sub-layer below the critical thickness for crystallization, while the laminated structure as a whole provides the necessary mechanical strength and maintains uniform spacing for precise patterning.
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 laminated layer maintains high dielectric constants and mechanical strength, preventing crystallization and defects in semiconductor devices, even after annealing, thereby improving the reliability and performance of semiconductor devices.
Implementation Method 1
a laminated layer containing TiO2 layer may be formed by plasma enhanced atomic layer deposition method
Implementation Method 2
a post treatment may be carried out to the laminated layer comprising the first layer and the second layer
Data Source
AI summary
Provided is a method for forming a TiO2—SiO2 laminated layer for suppressing a crystallization of TiO2 layer. In one embodiment, a TiO2—SiO2 laminated layer may be formed by alternately forming and stacking a TiO2 layer and a SiO2 layer by plasma atomic layer deposition. A TiO2—SiO2 laminated layer has a high film strength compared to the conventional SiO2 layer and a crystallization of TiO2 layer is suppressed by forming a laminated layer and controlling a cycle ratio of the step of forming a TiO2 layer to the step of forming a SiO2 layer.