Semiconductor Device Fabrication with Air Gap Insulation
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability due to increased parasitic capacitance between conductive features, which affects their performance and complexity.
Innovation Solution
The design incorporates air gaps or porous insulating layers between conductive line spacers and bottom contact spacers, along with impurity regions with tapering cross-sectional profiles, to reduce parasitic capacitance and enhance fabrication tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conductive features are scaled down to improve computing ability, then device dimensions are reduced, but parasitic capacitance between conductive features increases
Solution Approach 1:
The patent introduces air gaps as intermediary structures between conductive features (word lines and bit lines). These air gaps act as mediators that reduce the parasitic capacitance coupling between adjacent conductive lines by providing an insulating region with lower dielectric constant than traditional materials, thereby resolving the capacitance increase problem while maintaining scaled dimensions
Solution Approach 2:
The patent employs porous insulating materials or air gap structures between conductive features. These porous structures have lower effective dielectric constants compared to solid insulating materials, which directly reduces the parasitic capacitance between scaled-down conductive lines while maintaining the required electrical isolation
2Length of moving object
If device dimensions are scaled down to meet increasing computing demand, then device size is reduced, but fabrication complexity and difficulty increase
Solution Approach 1:
The patent forms air gaps and porous insulating structures at specific stages during the fabrication process, before subsequent deposition and patterning steps. This preliminary creation of low-k regions simplifies later processing by pre-establishing the electrical isolation framework, reducing the complexity of managing parasitic capacitance in subsequent fabrication steps
Solution Approach 2:
The patent applies different material properties and structures to specific local regions between conductive features. By creating air gaps or porous insulating layers only in critical capacitance regions rather than uniformly throughout the device, the patent reduces overall fabrication complexity while targeting the specific problem areas that contribute most to parasitic capacitance
Data Source
AI summary
The present application provides a method for fabricating a semiconductor device including providing a substrate, concurrently forming a first conductive line and a bottom contact on the substrate, concurrently forming a first conductive line spacer on a sidewall of the first conductive line and a bottom contact spacer on a sidewall of the bottom contact, forming a first insulating layer over the substrate and concurrently forming an air gap between the first conductive line spacer and the bottom contact spacer.