Thermal Vias Without Liner Layers for Heat Dissipation
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Solution Overview
Problem
Conventional integrated circuits (ICs) face challenges in effectively removing heat from die stacks or individual dies due to the thermal insulation provided by liner layers in via structures, which hinder efficient heat dissipation.
Innovation Solution
The implementation of a substrate with a plurality of vias, where at least one via lacks a liner layer, allowing a thermally conductive material to be deposited directly in the via to create a thermal via structure, thereby enhancing heat conduction without electrical conduction requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liner layer is deposited in all via openings to provide electrical insulation, then electrical isolation is improved, but thermal resistance increases and heat dissipation deteriorates
Solution Approach 1:
The patent applies different treatments to different via openings: some vias receive liner layers for electrical isolation while others are left liner-free for thermal conduction. This local differentiation allows each via type to perform its specific function optimally without compromising the other.
Solution Approach 2:
The via openings are segmented into two functional categories: electrical vias with liner layers for signal transmission and thermal vias without liner layers for heat dissipation. This segmentation enables independent optimization of electrical and thermal performance pathways.
2Reliability
If a liner layer is deposited in via openings to prevent material diffusion, then via structure reliability is improved, but thermal conductivity deteriorates
Solution Approach 1:
The liner layer is selectively applied only to electrical vias where diffusion prevention is needed, while thermal vias are deliberately left without liner layers to maximize thermal conductivity. This local quality approach ensures each via type has the appropriate properties for its function.
3Reliability
If conventional via structures with liner layers are used, then electrical connection reliability is improved, but heat removal capability deteriorates
Solution Approach 1:
The via system is segmented into electrical vias with liner layers for reliable signal transmission and thermal vias without liner layers for efficient heat removal. This functional segmentation allows simultaneous optimization of both electrical connection reliability and thermal management productivity.
Solution Approach 2:
The via opening structure serves dual purposes: electrical vias handle signal transmission with liner protection, while thermal vias handle heat dissipation without liners. The same basic via structure is adapted for different functions by selectively applying or omitting the liner layer.
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 approach significantly reduces thermal resistance and improves heat dissipation from ICs by eliminating the thermal insulation of liner layers, allowing for more efficient heat transfer through the substrate, as demonstrated by a 30% reduction in thermal resistance at a distance of approximately 500 microns from a hot spot.
Implementation Method 1
A thermally conductive material is disposed in the at least one of the plurality of vias to provide a thermal via structure
Data Source
AI summary
A method relating generally to a substrate is disclosed. In such a method, the substrate has formed therein a plurality of vias. A liner layer is located on the substrate, including being located in a subset of the plurality of vias. At least one of the plurality of vias does not have the liner layer located therein. A thermally conductive material is disposed in the at least one of the plurality of vias to provide a thermal via structure.