Semiconductor Interconnects with Air Gaps for Parasitic Capacitance Reduction
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Solution Overview
Problem
The challenge is to reduce parasitic capacitance in semiconductor devices with small feature sizes and high density while maintaining low resistance and using low-k dielectric materials, as existing approaches often lead to performance deterioration.
Innovation Solution
A semiconductor device design that includes a substrate with conductive patterns and air gaps, surrounded by multiple insulating patterns with varying materials and structures to minimize parasitic capacitance and prevent oxidation of metal patterns, utilizing a layered insulating structure with specific materials and interfaces to control the penetration of water and oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch of metal line is reduced to increase density, then device capacity increases, but parasitic capacitance increases causing performance deterioration
Solution Approach 1:
The patent extracts the harmful dielectric material between adjacent metal lines and replaces it with air gaps. By removing the solid dielectric material that causes parasitic capacitance and replacing it with air (which has minimal dielectric constant), the parasitic capacitance between closely-spaced metal lines is significantly reduced, enabling high-density interconnection without performance deterioration.
Solution Approach 2:
The patent introduces air gaps (porous structure) between metal lines instead of using solid dielectric material. These air gaps act as low-k dielectric regions that minimize parasitic capacitance while maintaining the structural integrity of the interconnection, allowing for reduced pitch and increased device capacity.
2Object-generated harmful factors
If low-k dielectric materials are used to reduce parasitic capacitance, then performance improves, but metal pattern oxidation may occur
Solution Approach 1:
The patent employs a composite structure combining air gaps with carefully selected insulating materials. The air gaps provide minimal dielectric constant for low parasitic capacitance, while adjacent insulating patterns made of oxidation-resistant materials protect the metal patterns from oxidation. This composite approach simultaneously achieves low parasitic capacitance and prevents metal oxidation.
Solution Approach 2:
The air gaps create an inert environment between metal lines, preventing oxygen from reaching and oxidizing the metal patterns. Air acts as a protective barrier that maintains the metal in its reduced state while providing the low-dielectric constant needed for minimal parasitic capacitance.
3Object-generated harmful factors
If air gaps are introduced to reduce parasitic capacitance, then performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent forms the air gap structure during the interlayer insulating layer formation process itself, rather than as a separate subsequent step. By integrating the air gap creation into the existing manufacturing flow (using the same spin coating, curing, and etching processes), the complexity is minimized while achieving the low parasitic capacitance benefit.
Solution Approach 2:
The interlayer insulating layer serves multiple functions: it provides electrical insulation between metal layers, creates air gaps for low parasitic capacitance, and protects metal patterns from oxidation. This multi-functionality reduces the need for additional specialized process steps, thereby limiting the increase in manufacturing 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
This design effectively reduces parasitic capacitance, enhances the reliability and electric characteristics of semiconductor devices by preventing metal pattern oxidation and improving RC delay, while maintaining low resistance and high density.
Implementation Method 1
The reduction in pitch of the metal line may lead to an increase in parasitic capacitance of a semiconductor device
Implementation Method 2
preventing metal pattern oxidation
Data Source
AI summary
A semiconductor device may include a substrate, a first interlayered insulating layer on the substrate having openings, conductive patterns provided in the openings, first to fourth insulating patterns stacked on the substrate provided with the conductive patterns, and a second interlayered insulating layer provided on the fourth insulating pattern.