Split Die-Region Package Substrate for IC Heat Dissipation
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Solution Overview
Problem
As IC dice shrink in size, power density increases, leading to higher heat generation, which can degrade performance and reduce lifespan due to thermal stresses, and existing thermal management techniques may compromise performance or be impractical in small form factor packages.
Innovation Solution
Implementing a thermal conductive semiconductor package substrate with a die region split, where the dielectric layer under the core die region has thicker metal contacts and higher thermal conductivity than the peripheral region, facilitating enhanced heat dissipation without compromising cross-talk shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional substrate is used with all die regions coplanar, then the fabrication process is simple, but thermal management is insufficient for 3D stacked architectures
Solution Approach 1:
The substrate is divided into multiple non-coplanar die regions (first die region, second die region, third die region) at different elevations. This segmentation allows each region to be optimized for specific thermal management requirements, with heat dissipation features positioned at different heights to effectively manage thermal loads from multiple stacked dies.
Solution Approach 2:
The substrate transitions from a conventional coplanar two-dimensional layout to a three-dimensional non-coplanar structure. Die regions are positioned at different elevations (z-dimension), enabling vertical thermal pathways and improved heat dissipation through the substrate thickness, which is critical for 3D stacked architectures.
2Temperature
If die regions are positioned at different elevations for thermal management, then thermal dissipation improves, but alignment precision between stacked dies becomes more difficult to achieve
Solution Approach 1:
Alignment features are pre-formed on the substrate surface at each die region elevation before die attachment. These pre-positioned alignment features (such as trenches, protrusions, or patterned structures) provide reference markers that guide precise die placement at the correct elevation and lateral position, ensuring accurate alignment across multiple stacked dies despite the non-coplanar configuration.
Solution Approach 2:
The substrate acts as an intermediary structure that mediates between thermal management requirements and alignment precision. By incorporating both thermal dissipation features (non-coplanar die regions) and alignment features (positioned at each elevation) into the substrate, it simultaneously enables improved thermal pathways while providing the necessary mechanical references for precise die stacking alignment.
3Temperature
If the substrate is designed with non-coplanar die regions, then heat dissipation pathways are improved, but the fabrication process complexity increases
Solution Approach 1:
Multiple functions are merged into a single substrate structure: thermal dissipation pathways, mechanical support for stacked dies, and alignment references. By integrating alignment features directly into the substrate fabrication process (through patterning and etching steps) rather than adding separate alignment components, the design achieves improved thermal pathways while minimizing fabrication complexity.
Solution Approach 2:
The non-coplanar substrate structure serves multiple purposes simultaneously: it provides thermal management through elevated die regions with improved heat pathways, mechanical support for 3D stacked architecture, and integrated alignment features for precise die positioning. This multi-functionality reduces the need for separate components and simplifies the overall fabrication process despite the three-dimensional 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 solution effectively dissipates heat from the core circuits while maintaining electrical integrity, reducing thermal stresses, and extending the lifespan of the IC package by optimizing heat dissipation and cross-talk shielding.
Implementation Method 1
thermal conductive package substrate
Data Source
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Figure 3A
AI summary
Integrated circuit (IC) packages employing a thermal conductive semiconductor package substrate with die region split and related fabrication methods are disclosed. The package substrate includes a die split where metal contacts in one or more dielectric layers of the package substrate underneath the IC die(s) are thicker (e.g., in a core die region) than other metal contacts (e.g., in a peripheral die region) in the dielectric layer. This facilitates higher thermal dissipation from the IC die(s) through the thicker metal contacts in the package substrate. Cross-talk shielding of the package substrate may not be sacrificed since thinner metal contacts of the package substrate that carry high speed signaling can be of lesser thickness than the thicker metal contacts that provide higher thermal dissipation. The dielectric layer in the package substrate may also include dielectric materials having different thermal conductivities to further facilitate thermal dissipation and/or desired electrical or mechanical characteristics.