Seal Ring in Fan-Out Redistribution Layer for CPI Reliability
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Solution Overview
Problem
Fan-out Wafer Level Packaging (FOWLP) technologies face mechanical strength issues due to the use of low-k or ultra low-k dielectric materials, leading to chip package interaction (CPI) reliability problems such as delamination and crack propagation during the dicing process.
Innovation Solution
Incorporating a seal ring in the fan-out region of the redistribution layer (RDL) extending concentrically outwards from the die, which is formed simultaneously with the RDL interconnects, to enhance mechanical strength and prevent delamination and crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-k or ultra low-k dielectric materials are used in the RDL to meet electrical performance requirements, then electrical performance is improved, but mechanical strength deteriorates causing CPI reliability issues
Solution Approach 1:
The patent divides the RDL into two functional regions: a prime region for electrical interconnects and a fan-out region for mechanical support. The seal ring is formed in the fan-out region using a separate material composition than the low-k dielectric in the prime region, allowing each region to be optimized for its specific function without compromise
Solution Approach 2:
Different material properties are applied to different regions of the RDL. The prime region uses low-k dielectric material for optimal electrical performance, while the fan-out region uses a seal ring material with superior mechanical strength properties to prevent delamination and crack propagation during dicing
Data Source
AI summary
Devices and methods for forming a device are disclosed. At least one die is provided. A redistribution layer having a fan-out region extends concentrically outwards from an outer perimeter of the at least one die. A seal ring is disposed in the fan-out region of the redistribution layer.