Interconnect Air Gap Capping to Reduce Parasitic Capacitance
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Solution Overview
Problem
The increasing parasitic capacitance and RC time delays in semiconductor devices due to reduced feature sizes are not adequately addressed by existing low dielectric materials, limiting further integration density improvements.
Innovation Solution
Incorporation of air gaps between metal features using a plasma treatment process to form capping portions that cap recesses, reducing line-to-line capacitance and RC time delays.
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 introduces air gaps (porous structures with k=1) between metal interconnect features to reduce parasitic capacitance. The air gaps are formed by removing mandrel materials after spacer formation, creating void spaces that electrically isolate adjacent metal lines and reduce capacitive coupling while maintaining small feature sizes for high integration density.
Solution Approach 2:
The patent employs a composite structure combining spacers, air gaps, and capping portions. The spacer material (first dielectric) and capping material (second dielectric) form a composite isolation structure with the air gap, creating a multi-material system that provides both mechanical support and electrical isolation to reduce parasitic capacitance in high-density interconnects.
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 changes the dielectric constant parameter by introducing air gaps (k=1) instead of using low-k dielectric materials. This parameter change achieves superior capacitance reduction while avoiding the processing challenges associated with low-k materials, as air gaps can be formed through standard spacer and etch processes without requiring specialized low-k material deposition or handling.
Solution Approach 2:
The patent extracts the dielectric function by replacing solid dielectric materials with air gaps. By removing the mandrel materials after spacer formation, the patent creates void spaces that provide electrical isolation without the processing complications of low-k dielectric materials, effectively taking out the problematic material while retaining the desired electrical isolation function.
3Object-generated harmful factors
If air gaps are incorporated to reduce parasitic capacitance, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The patent performs preliminary action by forming spacers around mandrels before removing the mandrels. This sequence ensures that the air gaps are precisely defined by the spacer structures, which are formed using standard conformal deposition techniques. The preliminary spacer formation simplifies the overall process compared to direct air gap formation methods, as the spacers serve as both structural elements and templates for the air gaps.
Solution Approach 2:
The patent uses spacers as intermediary structures to define and contain the air gaps. The spacers act as mediators that simplify the fabrication process by providing a straightforward method to create well-defined air gaps through conformal deposition and selective removal, avoiding the need for complex direct air gap formation techniques while achieving precise gap dimensions.
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 plasma treatment process effectively forms air gaps with a low dielectric constant, significantly reducing parasitic capacitance and RC time delays, enhancing semiconductor device performance.
Implementation Method 1
subjecting the patterned mask to a plasma treatment process such that mask portions of the patterned mask are deformed to form a capping portion
Data Source
AI summary
A method for manufacturing a semiconductor device includes: forming a patterned mask on a patterned structure disposed on a substrate, such that a first mask portion and a second mask portion of the patterned mask are disposed on a first interconnect feature and a second interconnect feature of the patterned structure, respectively; and subjecting the patterned mask to a plasma treatment process such that the first and second mask portions are deformed to form a capping portion to cap a recess disposed between the first and second interconnect features so as to form an air gap.