3D Stacked IC Dummy Dies for Heat Dissipation and ESD Mitigation
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Solution Overview
Problem
Three-dimensional (3D) packages of stacked integrated circuits face challenges in heat dissipation and electrical robustness, particularly due to confined heat within the package, which impairs functionality and reliability, and are susceptible to electrostatic discharge (ESD) and other capacitance-related effects.
Innovation Solution
Incorporating dummy dies with metal layers forming an intra-stack capacitor and thermally conductive substrates between functional dies to dissipate heat and mitigate ESD, while also providing additional power supply and improving mechanical stiffness through a stack configuration with a lid and thermal interface material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ICs are stacked in a 3D package, then device functionality and integration density are improved, but heat dissipation capability deteriorates due to confined heat within the package
Solution Approach 1:
The patent introduces dummy dies as intermediary elements between functional dies in the stack. These dummy dies contain metal layers that act as heat sinks, providing thermal pathways to conduct heat away from functional dies. The dummy dies serve as mediators that facilitate heat transfer from the confined functional dies to the package exterior, resolving the heat dissipation problem while maintaining high integration density.
Solution Approach 2:
The patent utilizes the vertical dimension (z-axis) by stacking multiple layers of functional and dummy dies. The metal layers within dummy dies extend in the horizontal dimensions while being positioned at different vertical levels, creating a three-dimensional thermal management architecture. This dimensional approach allows heat to be dissipated through multiple pathways in different spatial directions, effectively managing heat in the confined 3D package volume.
2Productivity
If multiple ICs are stacked in a 3D package, then device functionality is improved, but electrical robustness deteriorates due to susceptibility to electrostatic discharge (ESD)
Solution Approach 1:
The patent converts the potentially harmful ESD effects into beneficial functionality by incorporating metal layers in dummy dies that form capacitors. These capacitors utilize the ESD-related electrical phenomena to provide electrostatic discharge protection and power supply functions. The harmful ESD effects are transformed into useful energy storage and protection mechanisms, enhancing electrical robustness while maintaining device functionality.
Solution Approach 2:
The patent implements ESD protection mechanisms in advance by positioning dummy dies with metal layer capacitors throughout the stack. These capacitors are pre-configured to absorb and dissipate electrostatic discharge before it can reach and damage functional dies. The cushioning effect is built into the stack architecture itself, providing proactive protection against ESD events.
3Temperature
If dummy dies with metal layers are added to dissipate heat and mitigate ESD, then heat dissipation and electrical robustness are improved, but device complexity increases
Solution Approach 1:
The dummy dies are designed to perform multiple functions simultaneously: heat dissipation through metal layer thermal conduction, ESD mitigation through capacitor formation, and power supply provision. By making the dummy dies multi-functional, the patent reduces the need for separate dedicated components for each function, thereby managing device complexity while achieving improved heat dissipation and electrical robustness.
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
Enhances heat dissipation and electrical robustness by effectively managing heat and ESD within the electronic device, improving reliability and performance by reducing thermal stress and increasing the surface area for cooling.
Implementation Method 1
dummy dies... configured to: (i) dissipate heat generated by the one or more functional dies
Implementation Method 2
the first and second metal layers form an intra-stack capacitor for mitigating electrostatic discharge (ESD) effects within the electronic device
Data Source
AI summary
An electronic device, including a substrate and a stack of dies stacked on the substrate. The stack of dies includes: (a) one or more functional dies, the functional dies including functional electronic circuits and being configured to exchange electrical signals at least with the substrate, and (b) one or more dummy dies, the dummy dies being disposed among dies forming the stack and being configured to: (i) dissipate heat generated by the one or more functional dies and (ii) pass electrical signals exchanged between the substrate and the one or more functional dies or between two or more of the functional dies.