Air Gaps in Semiconductor Interconnects for Signal Speed
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Solution Overview
Problem
Semiconductor devices face challenges in achieving higher integration, lower power consumption, and faster operating speeds due to the high electrical resistivity of aluminum interconnection lines and electrical interference between closely spaced copper interconnection lines, which affects signal transfer speed.
Innovation Solution
The introduction of air gaps between conductive patterns in semiconductor devices, defined by insulating diffusion barrier layers and permeable layers, helps reduce electrical interference and increase signal transfer speed by varying the thickness of these layers to control the spacing and formation of air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as interconnection material to reduce electrical resistivity, then electrical conductivity is improved, but patterning difficulty increases due to etching challenges
Solution Approach 1:
A barrier layer is introduced as an intermediary between the copper interconnection line and the etching process. This barrier layer protects the copper from direct etching attack, enabling precise patterning while maintaining copper's excellent electrical conductivity properties
Solution Approach 2:
The interconnection structure uses a composite material system combining copper (for electrical conductivity) with a barrier layer material (for etching resistance). This composite approach leverages the strengths of each material to simultaneously achieve good electrical properties and manufacturability
2Productivity
If interconnection lines are spaced closer to increase integration density, then device integration is improved, but electrical interference between lines increases causing signal delay
Solution Approach 1:
Air gaps are extracted from the insulating material between adjacent copper interconnection lines, creating void spaces that eliminate dielectric material. This removal of insulating material reduces capacitive coupling and electrical interference between closely spaced lines, maintaining signal integrity at higher densities
Solution Approach 2:
The use of air gaps creates a porous structure between interconnection lines where the void spaces (porosity) are filled with air instead of solid dielectric material. This porous configuration reduces electrical interference while allowing closely spaced interconnections for high integration density
Data Source
AI summary
Semiconductor devices are provided. A semiconductor device includes gaps between conductive patterns. Moreover, the semiconductor device includes a permeable layer on the conductive patterns. Methods of fabricating semiconductor devices are also provided.