3D IC Heat Path Through TSV and RDL Stack for Thermal Dissipation
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Solution Overview
Problem
Conventional 3D integrated circuits face inefficiencies in heat dissipation due to dielectric materials that surround semiconductor devices, leading to heat buildup and potential damage to adjacent devices.
Innovation Solution
A 3D IC structure with a redistribution layer (RDL) stack that includes a heat path through a through substrate via (TSV) and RDL dielectric material with high thermal conductivity, coupled with specific phonon density of state (DOS) profiles and barrier layers to enhance heat transfer, reducing thermal interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dielectric materials surround semiconductor devices in 3D ICs, then device integration density is improved, but heat dissipation efficiency deteriorates
Solution Approach 1:
The patent segments the dielectric structure into multiple functional layers: a first dielectric layer surrounding the semiconductor device, a second dielectric layer with lower thermal conductivity surrounding the first layer, and a third dielectric layer with higher thermal conductivity positioned adjacent to the heat path. This segmentation allows different regions to serve different functions - electrical insulation where needed and heat conduction where required - resolving the contradiction between integration density and heat dissipation efficiency.
Solution Approach 2:
The patent applies local quality by assigning different thermal conductivity properties to different spatial regions of the dielectric structure. The third dielectric layer is specifically positioned to have high thermal conductivity in the region adjacent to the heat path, while other dielectric layers maintain lower thermal conductivity for electrical insulation. This localized optimization allows the system to achieve both high integration density and effective heat dissipation in critical areas.
2Reliability
If conventional dielectric materials are used to insulate semiconductor devices, then electrical insulation is improved, but thermal interface resistance increases
Solution Approach 1:
The patent introduces a third dielectric layer as an intermediary between the heat-generating semiconductor device and the ambient environment. This intermediate layer has specifically engineered properties: it provides electrical insulation like conventional dielectrics but simultaneously offers enhanced thermal conductivity to facilitate heat transfer. The third dielectric layer acts as a mediator that reconciles the conflicting requirements of electrical insulation and thermal management.
Solution Approach 2:
The patent employs composite dielectric structures combining multiple layers with different thermal and electrical properties. The combination of the first dielectric layer (providing base insulation), the second dielectric layer (providing additional insulation with controlled thermal properties), and the third dielectric layer (providing enhanced heat conduction) creates a composite structure that simultaneously satisfies both electrical insulation and thermal management requirements, reducing thermal interface resistance while maintaining reliability.
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 RDL stack enables efficient heat dissipation from high thermal output devices, protecting adjacent devices by reducing heat buildup and improving thermal management in 3D ICs.
Implementation Method 1
The RDL dielectric material has an RDL thermal conductivity that is over twenty times an interconnect thermal conductivity of an interconnect dielectric material of the first interconnect structure or of the second interconnect structure
Data Source
AI summary
A first die includes a first substrate and a first interconnect structure. A second die is bonded to the first die and includes a second substrate and a second interconnect structure, such that the first and second interconnect structures are arranged between the first and second substrates. A redistribution layer (RDL) stack is arranged on an outer side of the first die opposite the first interconnect structure. A heat path includes a through substrate via (TSV) extending from a conductive layer in the first interconnect structure, through the first substrate, and into the RDL stack. An RDL dielectric material is included in the RDL stack and separates the heat path from an ambient environment. A thermal conductivity of the RDL dielectric is over twenty times a thermal conductivity of an interconnect dielectric material of the first interconnect structure or of the second interconnect structure.