TSV Dielectric Liner Structure With Air Gaps for Lower Parasitic Capacitance
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Solution Overview
Problem
The existing semiconductor structures with through semiconductor vias (TSVs) face challenges in minimizing parasitic coupling capacitance, which increases delay and power consumption due to the interaction between TSV conductors and the semiconductor substrate with a dielectric liner in between.
Innovation Solution
Incorporating a plurality of discontinuous or elongated air gaps in the semiconductor substrate extending away from the dielectric liner surrounding the TSVs, which reduces the area of the semiconductor substrate acting as a capacitor electrode and alleviates stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric liner surrounds the TSV between the TSV and semiconductor substrate, then electrical insulation is provided, but parasitic coupling capacitance increases causing delay and power consumption increase
Solution Approach 1:
The continuous semiconductor substrate around the TSV is segmented by creating air gaps that divide it into separate regions. This segmentation reduces the effective area of the substrate acting as a capacitor electrode, thereby reducing parasitic coupling capacitance while maintaining the dielectric liner's insulation function.
Solution Approach 2:
Material is extracted from the semiconductor substrate to create air gaps in the form of trenches or voids. By removing substrate material in regions adjacent to the TSV, the capacitance-forming area is reduced without compromising the dielectric liner's electrical insulation between the TSV and remaining substrate.
2Loss of energy
If air gaps are created in the semiconductor substrate adjacent to the dielectric liner, then parasitic coupling capacitance is reduced, but manufacturing complexity increases
Solution Approach 1:
Air gap trenches are formed in the semiconductor substrate before TSV fabrication. By preparing the substrate with pre-formed air gap regions in advance, subsequent TSV processing can proceed without additional complex steps, integrating the capacitance reduction feature into the existing manufacturing flow.
Solution Approach 2:
The air gap structure is created using standard semiconductor fabrication techniques such as photolithography and etching, which are already established in the manufacturing process. This allows the complex air gap pattern to be reproduced reliably using existing equipment and methods rather than requiring new manufacturing approaches.
3Loss of energy
If air gaps extend away from the dielectric liner in the semiconductor substrate, then parasitic capacitance is reduced by up to 40.8%, but stress in the substrate is not adequately relieved
Solution Approach 1:
Air gaps are strategically positioned in specific regions adjacent to the TSV where they can simultaneously reduce parasitic capacitance and relieve substrate stress. The local placement of air gaps creates zones with different mechanical and electrical properties, optimizing both capacitance reduction and stress management in critical areas.
Solution Approach 2:
The structure creates a composite arrangement combining semiconductor substrate material and air gaps. This composite structure provides both electrical insulation for capacitance reduction and mechanical stress relief, as the air gaps act as stress-relief features while maintaining the overall structural integrity of the TSV assembly.
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 configuration effectively reduces parasitic coupling capacitance by up to 40.8% compared to structures without air gaps, while also providing stress relief in the semiconductor substrate, thereby enhancing the performance of integrated circuit structures.
Implementation Method 1
A parasitic coupling capacitance is formed by the TSV conductors and the semiconductor substrate with the dielectric liner therebetween. The parasitic coupling capacitance can increase delay and power consumption of the IC structures. It is a challenge to limit the parasitic coupling capacitance in this setting.
Data Source
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AI summary
A structure includes a through semiconductor via (TSV) in a semiconductor substrate, and a dielectric liner surrounding the TSV and between the TSV and the semiconductor substrate. A plurality of discontinuous air gaps is in the semiconductor substrate extending away from the dielectric liner, e.g., radially. The discontinuous air gaps reduce the parasitic coupling capacitance and relieve stress in the semiconductor substrate.