Selective Underfill for Perimeter IPD Reliability
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Solution Overview
Problem
The semiconductor industry faces challenges in enhancing the reliability and reducing manufacturing costs of package structures, particularly in Package-on-Package (PoP) technology, where mechanical forces on integrated passive devices (IPDs) near the perimeter of semiconductor dies can lead to failures and increased costs due to the need for uniform underfilling across all IPDs.
Innovation Solution
A method is introduced where an underfill is selectively formed between a subset of integrated passive devices (IPDs) proximate the perimeter of the die, using a capillary flow process or suitable deposition, to improve mechanical protection and reduce costs by omitting underfill for IPDs not subjected to significant mechanical forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform underfilling is applied to all IPDs, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies underfill selectively only to IPDs located at the perimeter of the die, rather than uniformly to all IPDs. This local quality approach recognizes that perimeter IPDs experience different mechanical stress conditions compared to interior IPDs, and thus only they require underfill protection, resolving the contradiction between reliability improvement and manufacturing cost reduction.
2Strength
If underfill is applied to all IPDs, then mechanical protection is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements a simplified manufacturing process by applying underfill only to perimeter IPDs through selective dispensing, rather than requiring uniform application to all IPDs. This reduces manufacturing complexity while maintaining adequate mechanical protection where it is most needed, addressing the contradiction between strength improvement and manufacturing complexity reduction.
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
This approach enhances the reliability of IPDs near the perimeter by mitigating mechanical stress while reducing manufacturing costs by selectively applying underfill only where necessary, thereby improving the overall package structure's integrity and efficiency.
Implementation Method 1
An underfill is formed between a subset of the IPDs and a redistribution structure of the package structure
Data Source
AI summary
A package structure and method of forming the same includes: a first package including: a first die; a via adjacent the first die; a molding compound encapsulating the via and at least laterally encapsulating the first die around a perimeter of the first die; and a first redistribution structure extending over the first die and the molding compound; a first integrated passive device (IPD) attached to the first redistribution structure, the first IPD disposed proximate the perimeter of the first die; a second IPD attached to the first redistribution structure, the second IPD disposed distal the perimeter of the first die; and an underfill disposed between the first IPD and the first redistribution structure, the second IPD being free of the underfill.