Redistribution Layer Via Geometry for Crack-Resistant IC Packages
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Solution Overview
Problem
Integrated circuit (IC) packages face reliability issues due to stress-induced cracks in redistribution layer (RDL) structures, which affect the performance and reliability of IC packages, especially under environmental stress like moisture, pressure, and temperature.
Innovation Solution
The development of specific RDL structures with a cap region, routing region, and intermediate region configurations, where the intermediate region's width along the peripheral edge of conductive vias is greater than the routing region's width, helps prevent stress-induced cracks by distributing stress more effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RDL structures are used, then manufacturing is simpler, but stress-induced cracks occur under environmental stress
Solution Approach 1:
The RDL structure is divided into three distinct regions: a cap region, a routing region, and an intermediate region. Each region serves a specific function in stress management and electrical routing, allowing the structure to handle environmental stress while maintaining manufacturing feasibility through defined geometric zones.
Solution Approach 2:
Different regions of the RDL structure are designed with different width characteristics. The intermediate region has a greater width than the routing region, creating local variations in structural properties that specifically address stress concentration at via interfaces while maintaining appropriate routing dimensions in other areas.
2Volume of moving object
If RDL width is reduced for scaling, then IC package size decreases, but stress concentration increases leading to cracks
Solution Approach 1:
The RDL structure implements local width variations where the intermediate region is deliberately widened relative to the routing region. This local expansion at critical stress points enhances stress resistance and prevents cracking, while the routing regions maintain reduced widths to achieve overall package scaling and miniaturization.
Solution Approach 2:
The design addresses stress distribution by utilizing the width dimension strategically at specific locations (intermediate region) rather than uniformly across the entire RDL. This dimensional variation allows stress management without compromising the overall compactness achieved through scaling.
Data Source
AI summary
A method of forming an integrated circuit (IC) package with improved performance and reliability is disclosed. The method includes forming a singulated IC die, coupling the singulated IC die to a carrier substrate, and forming a routing structure. The singulated IC die has a conductive via and the conductive via has a peripheral edge. The routing structure has a conductive structure coupled to the conductive via. The routing structure further includes a cap region overlapping an area of the conductive via, a routing region having a first width from a top-down view, and an intermediate region having a second width from the top-down view along the peripheral edge of the conductive via. The intermediate region is arranged to couple the cap region to the routing region and the second width is greater than the first width.