Thermal Vias in 3D Stacked IC Substrates
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Solution Overview
Problem
Conventional integrated circuits (ICs) face challenges in effectively removing heat from stacked dies due to limited thermal management capabilities.
Innovation Solution
The implementation of thermal via structures extending from the substrate toward a well without penetrating it, coupled with through-substrate via structures, facilitates heat conduction away from the substrate and to a heat sink, enhancing thermal conductivity between dies in a three-dimensional stacked IC configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal via structures are extended deeper into the substrate to improve heat conduction from hotspots, then thermal conductivity is improved, but the risk of electrical shorting to substrate wells increases
Solution Approach 1:
The via structure is segmented into two distinct parts: a thermal via portion that extends deep toward the well but stops before contact, and a through-substrate via portion that provides electrical isolation. This segmentation allows the thermal path to approach the well closely for efficient heat conduction while the through-via provides electrical isolation to prevent shorting.
Solution Approach 2:
The through-substrate via acts as an intermediary element between the deep thermal via and the substrate well. It provides electrical isolation while allowing thermal conduction to proceed, mediating between the need for deep thermal access and the need to prevent electrical shorting.
2Reliability
If through-substrate vias are added to provide electrical isolation, then electrical safety is improved, but device complexity increases
Solution Approach 1:
The via structure performs multiple functions simultaneously: the thermal via portion provides thermal conduction path, while the through-substrate via portion provides electrical isolation. This multi-functionality reduces the need for separate dedicated structures for each function.
Solution Approach 2:
The thermal via and through-substrate via are merged into a single continuous structure that extends through the substrate. This combining of functions into one integrated structure reduces overall device complexity compared to having separate thermal management and electrical isolation structures.
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 solution effectively manages heat dissipation in 3D stacked ICs by allowing for efficient thermal conductivity from hotspots to a heat sink, mitigating thermal build-up and improving the reliability of the ICs.
Implementation Method 1
facilitates heat conduction away from the substrate and to a heat sink, enhancing thermal conductivity between dies
Data Source
AI summary
An apparatus relates generally to a three-dimensional stacked integrated circuit. In such an apparatus, the three-dimensional stacked integrated circuit has at least a first die and a second die interconnected to one another using die-to-die interconnects. A substrate of the first die has at least one thermal via structure extending from a lower surface of the substrate toward a well of the substrate without extending to the well and without extending through the substrate. A first end of the at least one thermal via structure is at least sufficiently proximate to the well of the substrate for conduction of heat away therefrom. The substrate has at least one through substrate via structure extending from the lower surface of the substrate to an upper surface of the substrate. A second end of the at least one thermal via structure is coupled to at least one through die via structure of the second die for thermal conductivity.