Staggered Die Stacking via Planarized Mold Interconnects
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Solution Overview
Problem
Stacking multiple dies in electronic packages is challenging due to variations in die thickness and interconnect types, leading to issues with height accommodation, thermal expansion, and increased complexity in manufacturing and assembly.
Innovation Solution
The solution involves using planarized vias and a mold with a planar upper surface to directly couple an upper die to multiple lower dies, reducing the electrical path length and eliminating the need for interposers, thereby standardizing interconnects and minimizing thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If dies with different thicknesses are stacked, then the number of dies occupying substrate area increases, but height accommodation complexity increases requiring various sized solder bumps or interposers
Solution Approach 1:
A mold compound is introduced as an intermediary material that encapsulates the dies with different thicknesses. The mold provides a planar upper surface that eliminates the need for complex height accommodation structures like interposers or varied solder bumps, while still allowing the dies to be stacked on the substrate.
Solution Approach 2:
The package structure is segmented into distinct components: the substrate, multiple dies of varying thicknesses, and a mold compound that separately encapsulates each die. This segmentation allows each component to be optimized independently while maintaining overall package integrity.
2Reliability
If traditional stacking methods with interposers are used, then height differences are accommodated, but package size increases and manufacturing complexity increases
Solution Approach 1:
The mold compound serves multiple functions simultaneously: it encapsulates the dies for protection, provides height accommodation for dies with different thicknesses, and creates a planar upper surface for stacking additional dies. This merging of functions eliminates the need for separate interposer components.
Solution Approach 2:
The interposer component is extracted from the package structure entirely. Instead of using a separate interposer to accommodate height differences, the mold compound directly provides the necessary height accommodation and planarization functions.
3Adaptability or versatility
If various interconnect schemes are used across different dies, then die design flexibility is maintained, but manufacturing and assembly complexity increases
Solution Approach 1:
The mold compound acts as a universal interface that can accommodate various interconnect schemes on different dies. Whether the dies use different solder bump sizes, pitches, or patterns, the mold provides a standardized planar upper surface that simplifies the stacking process for subsequent dies.
Data Source
AI summary
An electronic package can include a substrate, a first die and a second die. The first die can include a first thickness and the second die can include a second thickness. The first and second dies can be coupled to the substrate. A mold can be disposed on the substrate and cover the first die and the second die. The mold can include a planar upper surface. A first via, having a first length, can be extended between the first die and the planar upper surface. A second via, having a second length, can be extended between the second die and the planar upper surface. In some examples, a third die can be communicatively coupled to the first die using the first via and the second die using the second via.