Dummy Support Die Structure for Fan-Out Package Warpage
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Solution Overview
Problem
Conventional semiconductor packaging technologies face challenges with warpage in fan-out packages, which affect bonding and solder joint reliability, and limitations in I/O pad density due to pitch constraints, especially as semiconductor dies become smaller and more functional.
Innovation Solution
The integration of a dummy support die with high thermal conductivity and rigidity is used to mechanically support the package, reducing warpage and improving thermal dissipation, while allowing for increased I/O pad density through redistribution layers and electrical connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fan-out packages are used to increase I/O pad density, then the number of I/O pads can be increased, but warpage occurs affecting bonding and solder joint reliability
Solution Approach 1:
A dummy support die is introduced as an intermediary component between the fan-out package and the package substrate. This dummy die provides mechanical support to reduce warpage while allowing the I/O pads to be redistributed over a larger area, thus increasing pad density without compromising bonding reliability
Solution Approach 2:
The physical parameters of the package structure are modified by adding a dummy support die with specific mechanical properties. This changes the overall stiffness and thermal characteristics of the package assembly, reducing warpage deformation during bonding processes while maintaining the fan-out configuration for high I/O density
2Adaptability or versatility
If die size is decreased to increase functional integration, then more functions can be integrated, but I/O pad density is limited by pitch constraints
Solution Approach 1:
The I/O pad layout transitions from a two-dimensional arrangement constrained by die pitch to a three-dimensional redistribution structure. Redistribution layers are formed that extend I/O pads beyond the original die boundaries, effectively increasing pad density without requiring smaller die dimensions, thus preserving functional integration capabilities
3Productivity
If conventional packaging is used before wafer sawing, then throughput is greater and cost is lower, but I/O pad density is limited by fan-in type constraints
Solution Approach 1:
The packaging process is resequenced by performing fan-out redistribution and dummy die attachment before wafer sawing. This preliminary action enables high I/O pad density to be achieved in the packaged state while still maintaining batch processing throughput, as the entire wafer can be processed together through the redistribution layers
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
The solution effectively reduces warpage and enhances thermal management, improving the reliability and yield of semiconductor packaging by maintaining I/O pad density and facilitating better bonding to package substrates.
Implementation Method 1
dummy support die with high thermal conductivity and rigidity is used to mechanically support the package, reducing warpage and improving thermal dissipation
Data Source
AI summary
A method includes encapsulating a first device die and a second device die in an encapsulating material, forming redistribution lines over and electrically coupling to the first device die and the second device die, and bonding a bridge die over the redistribution lines to form a package, with the package including the first device die, the second device die, and the bridge die. The bridge die electrically inter-couples the first device die and the second device die. The first device die, the second device die, and the bridge die are supported with a dummy support die.