Local Interconnect Layer Dielectric Pillar Parasitic Capacitance
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Solution Overview
Problem
Conventional approaches to reduce parasitic capacitance in transistors, such as guard rings, are not effective when they do not provide a hermetic seal, and known dielectric materials lack sufficient thermal conductivity for applications like amplifiers or switching circuits.
Innovation Solution
An integrated circuit structure with a local interconnect layer that includes a first dielectric material over a device and a second dielectric material with a lower effective dielectric constant, positioned adjacent to the first material, which reduces parasitic capacitance by using a dielectric pillar extending through the interconnect layer and conductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric materials are used to hermetically seal the device layer, then hermetic sealing is achieved, but thermal conductivity is insufficient for applications like amplifiers or switching circuits
Solution Approach 1:
The patent applies local quality by using different dielectric materials with different properties in different regions of the interconnect layer. Specifically, a first dielectric material with higher thermal conductivity is used in regions requiring heat dissipation (near amplifiers or switching circuits), while a second dielectric material providing hermetic sealing is used in other regions. This allows each region to have the optimal material properties for its specific function.
2Object-affected harmful factors
If guard rings are used to reduce parasitic capacitance in transistors, then parasitic capacitance reduction is attempted, but effective electrical isolation is not achieved without hermetic sealing
Solution Approach 1:
The patent uses dielectric materials as intermediaries between adjacent transistors to reduce parasitic capacitance. The low-k dielectric materials (with dielectric constants less than 3.5, preferably less than 2.5) are positioned between transistor components to act as electrical isolators, thereby reducing the parasitic capacitance that would otherwise exist between adjacent transistor terminals without requiring hermetic sealing.
3Object-affected harmful factors
If dielectric materials with lower dielectric constants are used to reduce parasitic capacitance, then electrical isolation is improved, but thermal conductivity decreases
Solution Approach 1:
The patent resolves this contradiction by applying local quality - using low-k dielectric materials (with dielectric constants less than 3.5) in regions where electrical isolation is the priority, and using high thermal conductivity dielectric materials in regions where heat dissipation is critical. This spatial differentiation of material properties allows the system to optimize for electrical isolation where needed while maintaining thermal management where required.
Solution Approach 2:
The patent employs composite materials by combining multiple dielectric materials with different properties within the same interconnect layer. The structure includes both low-k dielectric materials for electrical isolation and high thermal conductivity dielectric materials for heat dissipation, creating a composite dielectric system that delivers both electrical and thermal performance simultaneously.
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 capacitance across transistors, allowing for improved electrical isolation and thermal conductivity, enabling the integration of devices with high parasitic capacitance in amplifiers and switching circuits while maintaining hermetic sealing in other areas.
Implementation Method 1
One variable in particular is parasitic capacitance, which arises when a transistor exhibits electrical capacitance across its two terminals when the device is powered off. Parasitic capacitance may decrease the gain of a circuit, and more generally may reduce electrical isolation between nearby transistors within a device layer.
Implementation Method 2
Known dielectric materials for hermetically sealing a device may not be thermally conductive enough to suit some technical applications, e.g., amplifiers or switching circuits.
Data Source
AI summary
Embodiments of the disclosure provide an integrated circuit (IC) structure, including a device layer including a device on a substrate. A local interconnect layer is over the device layer, and includes a first dielectric material over the substrate. The first dielectric material has a first effective dielectric constant. A second dielectric material is over the device and adjacent the first dielectric material. The second dielectric material has a second effective dielectric constant less than the first effective dielectric constant.