Insulative Stack Structures With Reinforced Intermediate Regions
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Solution Overview
Problem
Microelectronic device designers face challenges in maintaining the rigidity of structures during the formation of vertical memory arrays, particularly during replacement gate processing, which can lead to undesirable collapse of stack structures due to reduced dimensions and unsupported tiers.
Innovation Solution
Incorporating intermediate regions within insulative structures, doped with chemical species such as carbon and boron, to enhance the rigidity and strength of insulative structures, thereby preventing collapse during the removal of sacrificial structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dimensions of structures are reduced to increase integration density, then integration density is improved, but rigidity of structures deteriorates
Solution Approach 1:
The patent applies local quality by creating an intermediate region within the insulative structure that has different material composition (doped with carbon and boron) and different mechanical properties (higher rigidity) compared to the rest of the insulative structure. This localized modification provides enhanced structural support precisely where needed during processing, while maintaining the overall reduced dimensions for high integration density.
Solution Approach 2:
The patent employs composite materials by combining differently doped regions within the insulative structure. The intermediate region contains carbon-doped and boron-doped silicon oxide with different dopant concentrations, creating a composite structure that optimizes both mechanical strength and electrical insulation properties while maintaining compact dimensions.
2Productivity
If dimensions of structures are reduced to increase integration density, then integration density is improved, but stability of structures deteriorates
Solution Approach 1:
The intermediate region with enhanced rigidity provides localized structural stability during processing operations such as sacrificial structure removal. This localized reinforcement prevents tier collapse and maintains structural integrity throughout the fabrication process, ensuring stable composition and architecture despite reduced overall dimensions.
3Strength
If intermediate regions with dopants are added to insulative structures, then rigidity is improved, but device complexity increases
Solution Approach 1:
The intermediate doped region is formed during the insulative structure formation process itself, using preliminary doping actions with carbon and boron. This preliminary incorporation of dopants during fabrication, rather than as a separate post-processing step, enhances rigidity while minimizing additional process complexity.
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 enhanced rigidity of insulative structures maintains their shape during processing, preventing tier collapse and ensuring uniformity and predictability in the formation of microelectronic devices, particularly in 3D memory arrays.
Implementation Method 1
FIG. 4B illustrates a dopant concentration profile across a height of the insulative structure depicted in FIG. 4A
Data Source
AI summary
A microelectronic device includes a stack structure including insulative structures and conductive structures vertically alternating with the insulative structures. At least one of the insulative structures includes interfacial regions proximate interfaces between the at least one of the insulative structures and two of the conductive structures vertically neighboring the at least one of the insulative structures; and an intermediate region interposed between the interfacial regions. The intermediate region has a different material composition and relatively greater strength than the interfacial regions.