RDL Reinforcement Structure for Low-k Edge Cracking and Delamination
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Solution Overview
Problem
Low-k dielectric materials used in redistribution layer (RDL) structures for semiconductor devices suffer from mechanical weakness and thermal instability, leading to structural integrity issues such as cracking and delamination due to thermal and mechanical stresses during processing, handling, and operation.
Innovation Solution
Incorporating peripheral reinforcement structures made of conductive material within the RDL structure, fabricated simultaneously with the conductive traces and dielectric layers, to provide mechanical interlock and prevent delamination, cracking, and enhance structural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If low-k dielectric materials are used in RDL structures, then charge buildup and cross-talk are reduced, but mechanical strength and thermal stability deteriorate
Solution Approach 1:
The patent employs low-k dielectric materials combined with reinforcement structures to create a composite system. The low-k dielectric layer provides electrical performance benefits by reducing charge buildup and cross-talk, while the reinforcement structure (comprising additional dielectric layers and support elements) provides mechanical strength and thermal stability. This composite approach allows both requirements to be satisfied simultaneously.
2Area of stationary object
If RDL structures extend laterally beyond die periphery in FOWLP, then external connections are provided at greater pitch, but structural integrity deteriorates
Solution Approach 1:
The RDL structure is segmented into multiple functional layers: the low-k dielectric layer for electrical performance, and a separate reinforcement structure comprising additional dielectric layers and support elements. This segmentation allows the lateral extension needed for FOWLP applications while the dedicated reinforcement layers maintain structural integrity throughout the extended area.
Solution Approach 2:
The reinforcement structure adds vertical dimensionality to compensate for lateral extension. By stacking multiple dielectric layers and incorporating support elements in the vertical direction, the structure gains dimensional stability that prevents degradation caused by large lateral extensions, enabling FOWLP configurations without sacrificing reliability.
3Adaptability or versatility
If multiple levels of traces with interposed dielectric layers are fabricated, then routing complexity is increased, but manufacturing complexity increases
Solution Approach 1:
The reinforcement structure serves multiple functions simultaneously: it provides mechanical support, thermal stability, and acts as part of the multi-level trace routing system. By integrating these functions into a unified structure rather than separate components, the patent reduces overall fabrication complexity while maintaining advanced routing capabilities.
Data Source
AI summary
Embodiments of a redistribution layer structure comprise a low-k dielectric material and incorporating a reinforcement structure proximate and inward of a peripheral edge thereof, the reinforcement structure comprising conductive material electrically isolated from conductive paths through the RDL structure. Semiconductor packages including an embodiment of the RDL structure and methods of fabricating such RDL structures are also disclosed.