Stacked Semiconductor Die Layout to Suppress Encapsulant Delamination
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Solution Overview
Problem
In semiconductor packages, the delamination of encapsulants from stacked semiconductor dies due to stress remains a challenge, particularly as the number of integrated circuits increases, requiring effective methods to enhance adhesion and prevent damage from external impacts.
Innovation Solution
The implementation of a stack package design where first semiconductor dies with overhang portions protrude farther into the encapsulant than second semiconductor dies, alternating stacking configurations, and using encapsulants that cover sides of the die stack to fill gaps and suppress delamination, while also exposing top surfaces for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple semiconductor dies are substantially perpendicularly stacked to increase integration density, then the quantity of integrated circuits increases, but stress-induced delamination of the encapsulant from the semiconductor dies occurs
Solution Approach 1:
The patent employs asymmetric stacking where semiconductor dies are arranged in alternating patterns with different orientations or configurations. Specifically, odd-numbered dies are stacked with their active surfaces facing upward while even-numbered dies are stacked with active surfaces facing downward, creating an asymmetric structure that distributes stress more evenly and prevents encapsulant delamination
Solution Approach 2:
The patent divides the stack into alternating segments of differently oriented dies. This segmentation allows stress to be distributed across multiple interfaces rather than concentrated at single planes, reducing the overall stress on the encapsulant and preventing delamination while maintaining high integration density
2Reliability
If the encapsulant covers all surfaces of stacked semiconductor dies for protection, then adhesion and protection are improved, but heat dissipation from top surfaces is reduced
Solution Approach 1:
The encapsulant is selectively applied to cover only the side surfaces and bottom surfaces of the semiconductor die stack, while leaving the top surfaces of alternating dies exposed. This segmented encapsulation approach provides protection where needed while maintaining heat dissipation pathways through the exposed top surfaces
Solution Approach 2:
Different surfaces of the semiconductor die stack receive different treatments: side and bottom surfaces are covered by the encapsulant for protection and stress distribution, while top surfaces remain exposed to facilitate heat dissipation. This local differentiation of encapsulation quality optimizes both protection and thermal management
Data Source
AI summary
A stack package includes stacked semiconductor dies and an encapsulant. The encapsulant is formed to cover sides of the stacked semiconductor dies. A first semiconductor die of the stack package has an overhang portion that protrudes farther into the encapsulant than a second semiconductor die of the stack package.