Confined Air Gaps Between Metal Features for RC Delay Reduction
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Solution Overview
Problem
The integration density of electronic components in semiconductor devices is limited by increasing parasitic capacitance due to reduced feature sizes, leading to higher power consumption and RC time delays, which existing low dielectric materials struggle to mitigate effectively.
Innovation Solution
The method involves forming air gaps using chemical vapor deposition and a series of processing steps, including patterning, deposition, and sacrificial feature removal, to create controlled air gaps that reduce capacitance between metal features, employing dielectric spacers and a sustaining layer to define and confine these gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
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 regions 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 significantly reduced while maintaining the miniaturized feature sizes needed 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 porous dielectric layers, patterning them, and then removing the sacrificial material. The resulting porous air-filled spaces provide low-k dielectric properties that reduce parasitic capacitance while allowing continued scaling of feature sizes
2Object-generated harmful factors
If low dielectric materials are used to reduce parasitic capacitance, then parasitic capacitance is reduced, but processing problems increase
Solution Approach 1:
The patent uses sacrificial dielectric materials that are intentionally designed to be temporary and removable. These sacrificial layers are deposited, patterned, and then completely removed to create air gaps. The fact that these materials are meant to be discarded simplifies the overall process by avoiding the need to integrate complex low-k materials that would require specialized processing equipment and conditions
Solution Approach 2:
The patent changes the dielectric constant parameter by replacing solid dielectric materials (k>2.5) with air gaps (k=1). This parameter change is achieved through a standard semiconductor fabrication process involving deposition of sacrificial layers, photolith patterning, and etch removal, rather than requiring integration of exotic low-k materials that would demand changes in processing parameters and equipment
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 enhances RC performance by creating well-controlled air gaps that minimize line-to-line capacitance, thereby improving the performance and efficiency of semiconductor structures.
Implementation Method 1
forming a plurality of dielectric spacers laterally covering the dummy structures to form a plurality of trenches defined by the dielectric spacers
Data Source
AI summary
A method for manufacturing a semiconductor structure includes forming a plurality of dummy structures spaced apart from each other, forming a plurality of dielectric spacers laterally covering the dummy structures to form a plurality of trenches defined by the dielectric spacers, filling a conductive material into the trenches to form electrically conductive features, selectively depositing a capping material on the electrically conductive features to form a capping layer, removing the dummy structures to form a plurality of recesses defined by the dielectric spacers, filling a sacrificial material into the recesses so as to form sacrificial features, depositing a sustaining layer on the sacrificial features, and removing the sacrificial features to form air gaps confined by the sustaining layer and the dielectric spacers.