Semiconductor Die Chamfers for Thermal Stress Relief in Packages
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Solution Overview
Problem
Semiconductor packages face challenges with thermal stress, particularly at specific locations due to the arrangement of semiconductor dies on the package substrate, leading to adhesive stress and potential delamination.
Innovation Solution
Incorporating stress-reduction structures, specifically chamfers at the corners of semiconductor dies, to mitigate thermal stress by altering the stress distribution and reducing the concentration of stress at critical points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor dies are arranged in three-dimensional stacked configurations to improve integration density, then integration density and bandwidth are improved, but thermal stress concentration and adhesive failure risk increase
Solution Approach 1:
The patent applies local quality by modifying only the corner regions of semiconductor dies with chamfers, while keeping the rest of the die structure intact. This localized modification reduces thermal stress concentration at corners without affecting the overall three-dimensional stacked configuration and integration density.
Solution Approach 2:
The chamfers are formed on the semiconductor dies before packaging and stacking. This preliminary action prevents thermal stress concentration from developing during subsequent thermal cycling, thereby preventing adhesive failure before it occurs.
2Reliability
If chamfers are formed at the corners of semiconductor dies to reduce thermal stress, then adhesive strength and reliability are improved, but manufacturing complexity increases
Solution Approach 1:
The stress reduction feature is segmented to only affect the corner regions of the semiconductor dies, rather than modifying the entire die surface. This segmentation minimizes the impact on manufacturing while achieving the stress reduction goal at the critical locations.
3Object-affected harmful factors
If corner portions of semiconductor dies are removed to form chamfers, then stress concentration is reduced, but die volume and active area are decreased
Solution Approach 1:
The chamfer modification is applied only to the corner portions of the semiconductor dies, preserving the majority of the die volume and active area. This localized approach reduces stress concentration while minimizing the loss of functional material.
Solution Approach 2:
The chamfers remove only the minimal necessary corner portions to achieve stress reduction, avoiding excessive material removal. This partial action is sufficient to mitigate stress concentration while preserving die volume.
Data Source
AI summary
A semiconductor package includes: a package substrate including a horizontal top surface; an interposer bonded to the top surface of the package substrate; a semiconductor die bonded to a top surface of the interposer, the semiconductor die including a bottom surface that faces the top surface of the interposer, and chamfers formed in corners of the bottom surface of the semiconductor die; and a molding layer surrounding the semiconductor die and filling the chamfers.