Air Gap TSV Structure for Parasitic Capacitance Reduction
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Solution Overview
Problem
In 3D integration technology, the parasitic capacitance of through silicon via (TSV) electrodes impacts the electrical characteristics of semiconductor devices, necessitating a reduction in parasitic capacitance to enhance performance.
Innovation Solution
A method involving the formation of a precursor structure with a conductor surrounded by an air gap, clamped by redistribution layers, which reduces parasitic capacitance by isolating the conductor from the substrate and surrounding elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through silicon via (TSV) electrode is formed to interconnect conductive pads, then electrical connections between conductive pads are established, but parasitic capacitance increases and electrical characteristics deteriorate
Solution Approach 1:
The patent introduces an air gap structure surrounding the TSV electrode, effectively creating a porous/void space that reduces dielectric material around the conductor. This air gap has significantly lower permittivity compared to conventional dielectric materials, thereby reducing parasitic capacitance while maintaining electrical connection functionality between conductive pads
Solution Approach 2:
The patent employs a composite structure combining conductor material (copper or other conductive material), liner material (adhesion barrier), and air gap (void space). This composite approach optimizes electrical conductivity while minimizing parasitic capacitance through the strategic use of low-permittivity air space surrounding the TSV electrode
2Reliability
If the conductor is surrounded by dielectric material for insulation, then electrical isolation is achieved, but parasitic capacitance and leakage current increase
Solution Approach 1:
The air gap structure serves as an insulating medium with extremely low permittivity, providing electrical isolation while minimizing parasitic capacitance and leakage current paths between adjacent conductive structures
Solution Approach 2:
The air gap creates an inert void environment around the TSV electrode, eliminating dielectric material that would otherwise create leakage current paths and parasitic capacitance, while the liner material maintains adhesion and prevents short circuits
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 air gap significantly reduces parasitic capacitance and leakage current density, improving the overall electrical performance of semiconductor devices.
Implementation Method 1
the existence of the TSV parasitic capacitance is a key to impact the electrical characteristic. Thus, further improvements are needed to reduce the parasitic capacitance and enhance performance of semiconductor device
Implementation Method 2
The air gap significantly reduces parasitic capacitance and leakage current density, improving the overall electrical performance of semiconductor devices
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a precursor structure including a substrate having a via hole, a liner on a sidewall of the via hole, a conductor in the via hole, a first and a second insulating layers respectively on the top and bottom surfaces, and a first and a second redistribution layers in contact with the conductor through a first hole in the first insulating layer and a second hole in the second insulating layer. A first opening and a second opening are then respectively formed in the first insulating layer and the second insulating layer to expose a portion of the liner. The liner is then etched through the first opening and the second opening to form an air gap surrounding the conductor. The first opening and the second opening are then filled to seal the air gap.