Air-Gap Semiconductor Interconnect Structure With Sacrificial Gap Formation
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Solution Overview
Problem
As semiconductor feature sizes decrease, parasitic capacitance between metal features increases, leading to higher power consumption and RC time delays, which existing low-k dielectric materials struggle to mitigate effectively due to processing challenges.
Innovation Solution
The method involves creating air gaps in semiconductor devices by forming a patterned laminate, depositing low-k dielectric materials, and using thermal degradable sacrificial features to generate air gaps, which are then confined by a sustaining layer, reducing parasitic capacitance and enhancing RC performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are reduced to improve integration density, then integration density is improved, but parasitic capacitance between metal features increases
Solution Approach 1:
The patent extracts the dielectric material from the space between metal features and replaces it with air gaps. By removing the solid dielectric material and creating void spaces filled with air (k=1), the parasitic capacitance between adjacent metal features is reduced while maintaining the reduced feature size geometry for high integration density.
Solution Approach 2:
The patent introduces porous air gap structures between metal features. These air gaps are created by depositing sacrificial materials and then removing them to create void spaces. The porous air-filled structure provides lower effective dielectric constant compared to solid dielectric materials, thereby reducing parasitic capacitance while maintaining mechanical support through the porous architecture.
2Object-generated harmful factors
If low-k dielectric materials are used to reduce parasitic capacitance, then parasitic capacitance is reduced, but processing problems increase
Solution Approach 1:
The patent uses sacrificial materials (such as organic polymers or other removable materials) that are deposited, patterned, and then completely removed to create air gaps. These sacrificial materials serve a temporary purpose during fabrication and are subsequently eliminated. This approach avoids the need to process and integrate permanent low-k dielectric materials, thereby reducing processing complexity while achieving the desired capacitance reduction.
Solution Approach 2:
The patent utilizes phase transition processes to create air gaps. Sacrificial materials are deposited in a solid phase, then removed through thermal decomposition, chemical etching, or other removal processes that transition the material from solid to gas/liquid phase and eliminate it. This phase transition approach simplifies the overall manufacturing process compared to integrating permanent low-k dielectric materials, as it avoids the need for specialized deposition and processing of sensitive dielectric layers.
3Object-generated harmful factors
If air gaps are introduced to reduce parasitic capacitance, then parasitic capacitance is reduced, but mechanical strength decreases
Solution Approach 1:
The patent segments the dielectric structure into multiple components: remaining dielectric material, air gaps, and supporting framework structures. By dividing the continuous dielectric into segmented regions with air gaps, the structure achieves lower effective dielectric constant while the supporting framework segments provide mechanical reinforcement. This segmentation allows simultaneous optimization of electrical performance and mechanical strength.
Solution Approach 2:
The patent creates a composite structure combining solid dielectric materials, air gaps, and supporting framework materials. This composite architecture leverages the low dielectric constant of air while using the mechanical strength of solid materials in a optimized configuration. The composite structure achieves both electrical performance improvement through air gaps and mechanical strength through the supporting framework, resolving the contradiction between capacitance reduction and structural integrity.
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 approach effectively reduces parasitic capacitance and RC time delays, improving semiconductor performance by incorporating air gaps that lower the dielectric constant and provide mechanical strength, thereby enhancing the integration density and efficiency of electronic components.
Implementation Method 1
thermal degradable sacrificial features to generate air gaps
Data Source
AI summary
A method for manufacturing a semiconductor structure includes preparing a dielectric structure formed with trenches respectively defined by lateral surfaces of the dielectric structure, forming spacer layers on the lateral surfaces, filling an electrically conductive material into the trenches to form electrically conductive features, selectively depositing a blocking layer on the dielectric structure, selectively depositing a dielectric material on the electrically conductive features to form a capping layer, removing the blocking layer and the dielectric structure to form recesses, forming sacrificial features in the recesses, forming a sustaining layer to cover the sacrificial features; and removing the sacrificial features to obtain the semiconductor structure formed with air gaps confined by the sustaining layer and the spacer layers.