Air Gap Insulation for Semiconductor Parasitic Capacitance
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Solution Overview
Problem
As semiconductor devices become more integrated, the narrow distance between conductive structures increases parasitic capacitance, which deteriorates device performance, and reducing the dielectric constant of dielectric materials has limitations in minimizing this capacitance.
Innovation Solution
The introduction of air gaps between conductive structures, capped with conductive and capping structures, to decrease parasitic capacitance, while stabilizing the air gaps and reducing contact resistance through increased metal content in conductive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between conductive structures is reduced to increase integration, then device integration is improved, but parasitic capacitance increases
Solution Approach 1:
The patent extracts the dielectric material between conductive structures and replaces it with air gaps, removing the harmful dielectric constant effect while maintaining the narrow spacing needed for high integration
Solution Approach 2:
The patent changes the dielectric parameter from solid dielectric material (high dielectric constant) to air (dielectric constant ≈ 1), fundamentally altering the electrical characteristics to reduce parasitic capacitance
2Object-generated harmful factors
If the dielectric constant of dielectric material is reduced to decrease parasitic capacitance, then parasitic capacitance is decreased, but the effect is limited due to high dielectric constant materials
Solution Approach 1:
The patent achieves maximum parameter change by transitioning from solid dielectric materials with high dielectric constants to air gaps with dielectric constant approximately equal to 1, providing the greatest possible reduction in parasitic capacitance
3Object-generated harmful factors
If air gaps are introduced to decrease parasitic capacitance, then parasitic capacitance is decreased, but air gaps become unstable and difficult to maintain
Solution Approach 1:
The patent introduces sacrificial spacer structures as intermediary elements that temporarily occupy the space between conductive structures during fabrication, then are removed to create stable air gaps, and finally capped with capping structures to maintain stability
Solution Approach 2:
The patent performs preliminary actions by forming sacrificial spacers and capping structures before finalizing the air gap structure, ensuring stability is built into the design from the fabrication stage
4Object-generated harmful factors
If metal content in conductive structures is increased to reduce contact resistance, then contact resistance is decreased, but device complexity increases
Solution Approach 1:
The patent uses composite conductive structures combining multiple metal layers with different properties, achieving low contact resistance through material composition rather than structural complexity
Data Source
AI summary
A semiconductor device includes a plurality of first conductive structures formed over a substrate, second conductive structures each formed between neighboring first conductive structures of the first conductive structures, air gaps each formed between the second conductive structures and the neighboring first conductive structures thereof, third conductive structures each capping a portion of the air gaps, and capping structures each capping the other portion of the air gaps.