Raft-Type RDL Structure with Ring-Shaped Vias for Semiconductor Packaging
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in efficiently forming redistribution layer structures that minimize area usage while ensuring structural integrity and reducing stress and cracking risks, particularly under temperature loading and coefficient of thermal expansion mismatches.
Innovation Solution
The formation of a raft-type redistribution layer (RDL) structure with ring-shaped vias and disk-shaped conductive plates, which increases contact area and enhances structural strength, and a spring-like configuration of RDLs to mitigate stress and cracking, allowing for efficient area usage and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional RDL structures are used, then manufacturing process is simpler, but area usage efficiency is poor and structural integrity is weak
Solution Approach 1:
The RDL structure is segmented into multiple functional components: ring-shaped vias for stress distribution, disk-shaped conductive plates for enhanced contact area, and spring-like configurations for flexibility. This segmentation allows each component to perform its specific function optimally, improving area usage efficiency while maintaining manageable manufacturing complexity through standardized fabrication processes.
Solution Approach 2:
The invention transitions from conventional planar RDL structures to a multi-dimensional configuration by incorporating vertical spring-like elements and stacked conductive plates. This dimensional transformation enables better space utilization and improved electrical connectivity without significantly increasing lateral footprint, thereby enhancing area usage efficiency.
2Reliability
If conventional RDL structures are used, then manufacturing process is simpler, but structural integrity and reliability are poor
Solution Approach 1:
The spring-like RDL configuration and ring-shaped vias are designed beforehand to cushion and absorb thermal expansion stresses before they can cause cracking or structural failure. This preventive design approach enhances reliability by addressing coefficient of thermal expansion mismatches proactively, while the standardized spring elements keep manufacturing complexity within acceptable limits.
Solution Approach 2:
The RDL structure employs composite material principles by combining different conductive materials and polymer layers with complementary properties. The ring-shaped vias and disk-shaped conductive plates create a composite structure that leverages the strengths of each material to improve overall structural integrity and reliability under thermal loading conditions.
3Strength
If contact area is increased to reduce stress, then structural strength improves, but area usage becomes less efficient
Solution Approach 1:
The spring-like RDL configuration acts as a flexible element that distributes contact stresses over a larger effective area without requiring a proportionally larger footprint. The flexible spring structure achieves enhanced structural strength through elastic deformation, allowing the same contact area to handle higher loads, thereby maintaining area usage efficiency while improving structural strength.
Solution Approach 2:
The ring-shaped vias and disk-shaped conductive plates introduce curvature and three-dimensional geometry to the RDL structure. This curvature increases the effective contact area and stress distribution capability without proportionally increasing the lateral footprint, thereby achieving improved structural strength while maintaining efficient area utilization.
Data Source
AI summary
A package structure is provided. The package structure includes a dielectric layer on a die, a RDL structure and a conductive terminal. The RDL structure comprises a redistribution layer in and on the dielectric layer. The redistribution layer comprises a via and a conductive plate. The via is located in and penetrating through the dielectric layer to be connected to the die. The conductive plate is on the via and the dielectric layer, and is connected to the die through the via. The conductive terminal is electrically connected to the die through the RDL structure. The via is ring-shaped.