Semiconductor Package Bump Support Structure for Cold Joint Prevention
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving high-density integration and reliable electrical connections due to limitations in feature size reduction and stress management during thermal cycles, which affect the yield and reliability of semiconductor packages.
Innovation Solution
The implementation of a semiconductor package structure that includes a redistribution layer with alternating dielectric and conductive layers, raised support structures around conductive bumps, and metal pillars for enhanced electrical connections, along with an interposer and encapsulant layer to provide structural support and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature size is reduced to achieve higher integration density, then integration density is improved, but manufacturing precision and reliability deteriorate due to stress management issues during thermal cycles
Solution Approach 1:
The patent segments the conductive bump structure into multiple functional layers: a base conductive bump, an intermediate raised support structure, and a top conductive feature. This segmentation allows each layer to independently manage stress and deformation during thermal cycling, preventing failure in high-density configurations
Solution Approach 2:
The patent transitions from a two-dimensional planar conductive bump to a three-dimensional raised support structure with vertical walls and a top surface. This dimensional change provides additional structural support and stress distribution pathways, enabling reliable electrical connections at reduced feature sizes
2Quantity of substance
If feature size is reduced to achieve higher integration density, then integration density is improved, but manufacturing precision deteriorates due to stress-related defects
Solution Approach 1:
The raised support structure is formed beforehand to provide a pre-engineered stress-absorbing framework before subsequent manufacturing steps. This preemptive structural reinforcement compensates for stress-induced dimensional variations that would otherwise occur during thermal cycling and processing
Solution Approach 2:
The patent applies different material properties and structural characteristics to different regions: the raised support structure has vertical walls with specific thicknesses for stress resistance, while the top conductive feature has optimized geometry for electrical performance. This localized optimization maintains precision across the entire structure despite overall size reduction
3Device complexity
If conventional packaging structures are used, then device complexity is maintained at acceptable levels, but electrical connection reliability deteriorates due to insufficient structural support to conductive bumps
Solution Approach 1:
The raised support structure is formed in advance before the final conductive bump is completed. This preliminary action establishes a robust structural foundation that prevents subsequent manufacturing defects and ensures reliable electrical connections without requiring complex post-processing steps
Data Source
AI summary
A package structure includes an interposer, a die, a conductive terminal and an interconnection structure that is disposed on a first side of the interposer. The die is electrically bonded to the interposer and disposed over the interconnection structure. The conductive terminal is connected to the interposer and the die via a conductive bump. In order to effectively avoid cold joint issues, round or rectangular polyimide structures are first disposed under the bumps to structurally support the bump and sufficiently increase bump height for improved electrical connection and long term reliability of the package structure.