Integrated Fan-Out Package Conductive Post Bonding
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing fabrication costs of integrated fan-out packages, which are becoming increasingly popular due to their compactness, while maintaining high integration density and efficiency.
Innovation Solution
The process involves using pre-fabricated conductive posts with specific profiles and a reflowing process to bond them onto redistribution conductive layers, eliminating the need for complex fabrication steps like sputtering, photolithography, and photoresist stripping, thereby reducing costs and cycle time, and ensuring coplanarity without additional grinding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fabrication processes (sputtering, photolithography, photoresist stripping) are used to form conductive posts, then manufacturing precision and reliability are improved, but fabrication cost and cycle time increase
Solution Approach 1:
Conductive posts are pre-formed with specific profiles (e.g., tapered shapes) before mounting onto the substrate. This preliminary formation of conductive posts with optimized geometries enables direct bonding through reflowing processes, eliminating the need for subsequent sputtering, photolithography, and photoresist stripping steps, thereby reducing fabrication cycle time while maintaining bonding reliability
Solution Approach 2:
The invention changes the physical and geometric parameters of conductive posts by pre-forming them with specific profiles (e.g., tapered shapes with controlled aspect ratios). These parameter optimizations enable the conductive posts to achieve proper alignment and bonding through reflowing alone, replacing complex multi-step fabrication processes and reducing overall manufacturing time
2Manufacturing precision
If additional grinding processes are applied to achieve coplanarity of conductive posts, then manufacturing precision is improved, but fabrication cost and process complexity increase
Solution Approach 1:
Conductive posts are pre-formed with controlled profiles (e.g., tapered shapes with specific angle ranges) that ensure proper alignment and coplanarity during the reflowing bonding process. This preliminary geometric control eliminates the need for additional grinding processes, reducing fabrication process complexity while maintaining manufacturing precision
Solution Approach 2:
The invention employs asymmetric tapered profiles for conductive posts rather than symmetric cylindrical shapes. The tapered geometry (with specific angle ranges like 10-45 degrees) provides self-aligning characteristics during reflowing, enabling coplanarity to be achieved through the bonding process itself without requiring subsequent grinding operations
3Productivity
If pre-fabricated conductive posts with specific profiles are used, then fabrication cost and cycle time are reduced, but manufacturing precision may be compromised
Solution Approach 1:
The invention optimizes specific geometric parameters of pre-formed conductive posts, including tapered angles (10-45 degrees), aspect ratios (0.5-2.0), and tip radii (1-10 micrometers). These parameter ranges are carefully selected to ensure that the conductive posts achieve proper alignment, coplanarity, and bonding strength through the reflowing process alone, maintaining manufacturing precision while improving fabrication efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces fabrication costs and cycle time, enhances coplanarity of conductive posts, and maintains high integration density, making the process more efficient and cost-effective for integrated fan-out packages.
Implementation Method 1
a reflowing process to bond them onto redistribution conductive layers
Implementation Method 2
a reflowing process to bond them onto redistribution conductive layers
Data Source
AI summary
Provided is an integrated fan-out package including a die, a first redistribution circuit structure, a second redistribution circuit structure, a plurality of solder joints, a plurality of conductive posts, and an insulating encapsulation. The first redistribution circuit structure and the second redistribution circuit structure are formed respectively over a back surface and an active surface of the die to sandwich the die. The solder joints are formed aside the die and connected to the first redistribution circuit structure. The conductive posts are formed on the solder joints and connected to the second redistribution circuit structure, and connected to the first redistribution circuit structure through the solder joints. A plurality of sidewalls of the die, a plurality of sidewalls of the conductive posts, and a plurality of sidewalls of the solder joints are encapsulated by the insulating encapsulation. A fabricating process of the integrated fan-out package is also provided.