3D IC Package Heat Paths Using Dummy Vias and Direct Bonding
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Solution Overview
Problem
The challenge in semiconductor packaging is effectively dissipating heat generated by high-density electronic components while maintaining a small form factor and improving integration density.
Innovation Solution
The implementation of metal heat dissipation structures, such as dummy vias, dummy bond pads, and dummy gap-filling regions, along with the use of insulating high thermal conductivity materials for isolation layers, and thinning or omitting bonding layers to reduce thermal resistance, facilitates efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-density electronic components are integrated into a smaller area, then integration density is improved, but heat dissipation becomes more difficult
Solution Approach 1:
The patent transitions from planar heat dissipation to three-dimensional heat dissipation by stacking multiple semiconductor dies vertically and providing separate heat dissipation paths for each die through the substrate. This allows heat to be dissipated in the vertical dimension rather than being confined to the horizontal plane, resolving the heat dissipation difficulty caused by high integration density.
Solution Approach 2:
The patent divides the heat dissipation function into separate segments for each semiconductor die. Each die has its own dedicated heat dissipation path through the substrate to external heat sinks, allowing independent thermal management of each component rather than relying on shared planar pathways.
2Temperature
If bonding layers are thinned or omitted to reduce thermal resistance, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the thickness parameter of bonding layers from conventional dimensions to thinned or omitted configurations. By reducing bonding layer thickness to minimal required levels or eliminating them entirely in favor of direct bonding, thermal resistance is significantly reduced while the patent manages the resulting manufacturing complexity through integrated process design.
3Temperature
If metal heat dissipation structures are added to improve thermal management, then heat dissipation efficiency is improved, but device complexity increases
Solution Approach 1:
The patent designs metal heat dissipation structures that serve multiple functions: they provide thermal conduction pathways for heat dissipation, act as electrical interconnects between dies, and serve as mechanical bonding interfaces. This multi-functionality reduces the need for separate dedicated heat dissipation structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the heat dissipation function with existing electrical interconnect structures. Metal vias and interconnect layers that would otherwise serve only electrical purposes are configured to also serve as thermal conduction pathways, combining multiple functions into single structures and avoiding additional complexity from separate thermal management components.
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 enhances thermal dissipation efficiency, manages hot spots effectively, eases integration with SoIC processes, and supports various package configurations, offering advantages in manufacturing and thermal management.
Implementation Method 1
an isolation layer may be formed of an insulating high thermal conductivity material
Implementation Method 2
a first dummy via penetrating through the isolation layer and into the semiconductor substrate; a bonding layer on the isolation layer
Data Source
AI summary
A device package includes a first die comprising a semiconductor substrate; an isolation layer on the semiconductor substrate, wherein the isolation layer is a first dielectric material; a first dummy via penetrating through the isolation layer and into the semiconductor substrate; a bonding layer on the isolation layer, wherein the bonding layer is a second dielectric material that has a smaller thermal conductivity than the first dielectric material; a first dummy pad within the bonding layer and on the first dummy via; a dummy die directly bonded to the bonding layer; a second die directly bonded to the bonding layer and to the first dummy pad; and a metal gap-fill material between the dummy die and the second die.