Glass-Core Package Substrates Using Disaggregated Redistribution Blocks
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Solution Overview
Problem
The existing methods for fabricating package substrates with increasing interconnects face challenges such as high defect rates and yield losses, particularly with large substrates, and the fragile nature of glass cores limits the usable fabrication processes.
Innovation Solution
The approach involves disaggregating redistribution blocks from the glass core, allowing for individual testing and consolidation of only known good blocks, and using hybrid bonding or solder bonding to attach them back to the core, enabling more flexible and cost-effective fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional monolithic fabrication methods are used for package substrates, then manufacturing simplicity is maintained, but defect rates increase and yield losses occur particularly with large substrates
Solution Approach 1:
The package substrate is divided into multiple discrete redistribution blocks that can be fabricated, tested, and assembled separately. Each block contains a portion of the interconnects and is tested individually before consolidation, allowing defect isolation and reducing overall defect rates in the final substrate.
2Strength
If glass cores are used in package substrates, then mechanical strength is enhanced, but the fragile nature limits usable fabrication processes
Solution Approach 1:
By segmenting the substrate into redistribution blocks that are assembled onto the glass core rather than fabricated directly on it, the method enables use of fabrication processes that would be too aggressive for glass, while still achieving the mechanical strength benefits of glass cores in the final assembly.
Solution Approach 2:
The glass core serves as an intermediary substrate that provides mechanical strength and thermal stability during assembly, while the redistribution blocks provide the interconnect functionality. This separation allows independent optimization of each component's fabrication process.
3Productivity
If disaggregated redistribution blocks are used, then yield losses are reduced through individual testing, but device complexity increases
Solution Approach 1:
Each redistribution block is tested individually before consolidation into the final substrate assembly. This preliminary testing allows early detection and removal of defective blocks, preventing propagation of defects through subsequent fabrication steps and improving overall yield.
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 method reduces yield losses and costs by ensuring only defect-free blocks are used, and allows for the use of processes that might damage glass cores, enhancing the mechanical strength and efficiency of the package substrate fabrication.
Implementation Method 1
using hybrid bonding or solder bonding to attach them back to the core
Implementation Method 2
solder bumps are formed on contact pads at both ends of the TGVs
Data Source
AI summary
Disaggregated package substrates with glass cores are disclosed. An example package substrate includes a glass core having a first side and a second side opposite the first side. The example package substrate further includes a first block of redistribution layers on the first side of the glass core. The example package substrate also includes a second block of redistribution layers on the first side of the glass core. The first block is distinct from the second block.