Dummy Semiconductor Features for 3DIC Heat Spreading
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Solution Overview
Problem
Heat dissipation in Three-Dimensional Integrated Circuits (3DICs) is inefficient due to materials like underfill and molding compound that trap heat, leading to local temperature peaks and thermal crosstalk, which affects the performance and reliability of the package.
Innovation Solution
Incorporating dummy semiconductor features with high thermal conductivity around the die stack, electrically isolated from the integrated circuit die and die stack, to facilitate heat removal and prevent heat buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat dissipation materials like underfill and molding compound are used in 3DIC packaging, then the package structure is complete and protected, but heat is trapped leading to local temperature peaks and thermal crosstalk
Solution Approach 1:
A dummy semiconductor feature with high thermal conductivity is introduced as an intermediary element between the inner die and the heat spreader. This intermediary provides an additional heat transfer pathway, allowing heat to bypass the thermally resistive underfill and molding compound materials while maintaining the protective package structure.
Solution Approach 2:
The solution employs a composite approach by combining the dummy semiconductor feature (high thermal conductivity material) with the existing package materials (underfill and molding compound with lower thermal conductivity). This creates a multi-path thermal management system where heat can travel through both the thermally conductive dummy feature and the protective package materials.
2Loss of energy
If heat is conducted through outer components to a heat spreader, then heat dissipation is achieved, but the path is blocked by materials with poor thermal conductivity
Solution Approach 1:
The heat dissipation path is segmented into multiple independent channels: one through the outer components and heat spreader, and another through the dummy semiconductor feature. This segmentation allows heat to be dissipated through parallel pathways, reducing the blocking effect of any single material layer.
Solution Approach 2:
The solution adds a vertical dimension to heat dissipation by placing the dummy semiconductor feature between the inner die and the heat spreader, creating a direct through-silicon via-like thermal pathway. This dimensional addition provides a shortcut for heat flow that bypasses the horizontal path through the thermally resistive underfill and molding compound.
3Temperature
If dummy semiconductor features are added to improve heat dissipation, then thermal performance is enhanced, but device complexity increases
Solution Approach 1:
The dummy semiconductor feature is designed to replicate the thermal conduction properties of actual semiconductor materials without requiring full functional circuitry. This copying approach allows the use of simple, thermally conductive structures that mimic the thermal behavior of active devices while serving purely as heat dissipation elements.
Solution Approach 2:
The solution changes the thermal conductivity parameter of the package structure by introducing the dummy semiconductor feature with high thermal conductivity. This parameter change directly addresses the thermal performance issue while the feature's simple geometric structure minimizes the increase in overall device complexity.
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 dummy semiconductor features effectively reduce operating temperatures and enhance the reliability and electrical performance of the device package by improving heat dissipation.
Implementation Method 1
Incorporating dummy semiconductor features with high thermal conductivity around the die stack, electrically isolated from the integrated circuit die and die stack, to facilitate heat removal and prevent heat buildup
Data Source
AI summary
In an embodiment, a device includes: an integrated circuit die having a first side and a second side opposite the first side; a die stack on the first side of the integrated circuit die; a dummy semiconductor feature on the first side of the integrated circuit die, the dummy semiconductor feature laterally surrounding the die stack, the dummy semiconductor feature electrically isolated from the die stack and the integrated circuit die; a first adhesive disposed between the die stack and the dummy semiconductor feature; and a plurality of conductive connectors on the second side of the integrated circuit die.