Underfill Control Structures for Semiconductor Reliability
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Solution Overview
Problem
In semiconductor device manufacturing, the underfill material used to protect and isolate surface devices can creep and interfere with adjacent external connection underbump metallizations, leading to contamination and undesired interactions, which affects the reliability and efficiency of the device.
Innovation Solution
The use of spacers, such as first and second spacers formed from conductive materials like titanium or nickel, positioned between the surface device underbump metallizations and external connection underbump metallizations, acts as a physical barrier to prevent the underfill material from creeping and contacting the external connections, thereby maintaining the integrity of the metallizations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If underfill material is dispensed to protect and isolate surface devices, then device protection and isolation are improved, but underfill material creeps and contaminates external connection underbump metallizations
Solution Approach 1:
A spacer structure is introduced as an intermediary element positioned between the surface device underbump metallization and the external connection underbump metallization. This spacer acts as a physical barrier that prevents underfill material from creeping onto and contaminating the external connection metallizations, while still allowing the underfill to perform its protective function for the surface device.
Solution Approach 2:
The underbump metallization structure is segmented into distinct regions: a surface device underbump metallization area, an external connection underbump metallization area, and a spacer region separating them. This segmentation creates controlled zones that allow underfill dispensing for surface device protection while preventing underfill migration to external connection areas through the spacer boundary.
2Object-affected harmful factors
If spacers are added to prevent underfill creep, then contamination is prevented, but device complexity increases
Solution Approach 1:
The spacer structure is merged with the underbump metallization formation process. The spacer is formed as part of the same metallization layers and patterning steps, combining the spacer function with the existing underbump metallization structure rather than adding a completely separate component, thereby minimizing the increase in device complexity.
Data Source
AI summary
A semiconductor device and method of reducing the risk of underbump metallization poisoning from the application of underfill material is provided. In an embodiment a spacer is located between a first underbump metallization and a second underbump metallization. When an underfill material is dispensed between the first underbump metallization and the second underbump metallization, the spacer prevents the underfill material from creeping towards the second underbump metallization. In another embodiment a passivation layer is used to inhibit the flow of underfill material as the underfill material is being dispensed.