Interconnect Air Gap Structure for Uniform Low-Capacitance Spacing
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Solution Overview
Problem
As semiconductor feature sizes decrease, the distance between interconnect metal features reduces, leading to increased parasitic capacitance, higher power consumption, and RC delay, with current manufacturing processes struggling to form uniform air gaps to mitigate these issues due to challenges in filling trenches with dielectric material and controlling gap size and shape.
Innovation Solution
A method involving the formation of functionalized polymers on the dielectric layer within trenches, followed by polymerization and thermal annealing to create self-aligned air gaps, ensuring consistent reduction of RC delay and signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If feature sizes are decreased to continue scaling, then device integration density is improved, but parasitic capacitance and RC delay increase due to reduced distance between interconnect metal features
Solution Approach 1:
The patent introduces an intermediary material layer (such as porous dielectric material or air gap) between adjacent interconnect metal features. This intermediary layer acts as a mediator that reduces the parasitic capacitance coupling between closely spaced conductors, thereby reducing RC delay and power consumption while allowing continued scaling of feature sizes
Solution Approach 2:
The patent employs porous dielectric materials filled into trenches between interconnects. The porous structure provides lower effective dielectric constant compared to solid dielectric materials, which reduces parasitic capacitance between adjacent metal lines. This enables continued miniaturization while maintaining acceptable signal integrity and power characteristics
2Ease of manufacture
If conventional manufacturing processes are used to form air gaps, then process simplicity is maintained, but manufacturing precision deteriorates due to inability to form uniform air gaps with controlled size and shape
Solution Approach 1:
The patent employs a self-aligned fabrication process where the air gap formation is automatically positioned relative to the interconnect structures without requiring separate alignment steps. The process uses self-aligned masks and sequential deposition/etching steps that inherently create uniform air gaps with precise dimensions, eliminating the need for complex external alignment procedures while achieving high manufacturing precision
Solution Approach 2:
The patent performs preliminary actions by first forming precise trench structures and depositing conformal dielectric layers before creating the final air gaps. These preliminary steps establish the geometric framework that ensures uniform air gap formation, with precise control over gap size and shape achieved through controlled deposition thickness and selective etching processes performed in advance
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
The method effectively forms uniform air gaps between interconnects, reducing RC delay and electronic signal interference, thereby improving semiconductor device performance.
Implementation Method 1
polymerization and thermal annealing to create self-aligned air gaps
Implementation Method 2
polymerization and thermal annealing to create self-aligned air gaps
Data Source
AI summary
A semiconductor device includes a substrate, a conductive interconnect structure disposed on the substrate, a plurality of air gap structures disposed on the conductive interconnect structure and spaced apart from each other, and a plurality of conductive interconnects disposed on the conductive interconnect structure and alternating with the plurality of the air gap structures. Each of the plurality of the air gap structures includes a dielectric portion and an air gap. The air gap of each of the plurality of the air gap structures is confined by the dielectric portion of the each of the plurality of the air gap structures and two corresponding ones of the plurality of the conductive interconnects.