Metallic Spring Anchor for FOPLP Die Placement
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Solution Overview
Problem
Advanced packaging technologies like FOPLP and FOWLP face challenges in die placement accuracy due to displacement errors during epoxy molding and pick-and-place processes, leading to yield penalties and high costs associated with sequential metrology and alignment corrections.
Innovation Solution
A die placement control method using metallic spring features anchored to the substrate, which provides precise positioning by forming metallic frames and spring features to securely hold chips in place during pick-and-place and epoxy molding, reducing displacement errors and eliminating the need for costly lithographic corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sequential metrology and alignment correction is performed at lithography process step, then die placement accuracy is improved, but throughput decreases and cost increases
Solution Approach 1:
The patent applies preliminary action by pre-defining targeted locations with predetermined dimensional tolerances and creating metallic spring anchor features before die placement. The metallic frame structures are formed in advance on the substrate, establishing precise positioning references that guide subsequent die placement without requiring post-placement metrology and correction steps, thus maintaining accuracy while improving throughput
Solution Approach 2:
The patent replaces the sequential metrology and lithographic correction system with a mechanical positioning system using metallic spring anchors and framed structures. The metallic frames provide physical constraints and positioning references that eliminate the need for complex optical measurement and iterative alignment correction processes, thereby improving throughput while maintaining placement accuracy
2Productivity
If dedicated metrology equipment is used to capture die displacement, then throughput increases and cost decreases, but large capital cost is required
Solution Approach 1:
The patent applies self-service by designing the substrate with integrated metallic frame structures and spring anchors that automatically provide positioning references and displacement compensation. The system is self-contained and does not require external dedicated metrology equipment to capture and correct die displacement, thereby improving throughput while avoiding large capital costs for specialized measurement tools
3Manufacturing precision
If site-by-site correction is performed after each site's displacement is characterized, then die placement accuracy is improved, but process time increases
Solution Approach 1:
The patent eliminates iterative site-by-site correction by pre-defining all targeted locations with predetermined dimensional tolerances and creating corresponding metallic spring anchor features before die placement begins. All positioning references are established in advance, allowing parallel processing and eliminating sequential correction steps, thus maintaining accuracy while reducing process time
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 significantly enhances die placement accuracy, reduces production costs, and increases throughput by ensuring accurate chip positioning without the need for conventional lithographic exposure corrections, making it suitable for heterogeneous integration and high-performance applications.
Implementation Method 1
The metal anchor structure is a spring feature, which provides force to fix the incoming chips at the locations without or with only minimized movement after die release
Implementation Method 2
The plated metallic anchor structure can be made by either a spring alloy or a magnetic spring alloy metal
Data Source
AI summary
An Fan-out packaging system, comprising dedicated frame with associated movable metallic spring feature(s) for incoming known-good-die (KGD), is invented. The movable spring anchor(s) along with the boundaries of the frame locks the KGD in its designated position during EMC implementation and subsequent processes. In this system/approach, the position accuracy of KGDs during the wafer reconstitution process will be mostly dominated by the dicing accuracy. The proposed system is a very low cost approach as it does not need the expensive software/tool set and does not have a low throughput site-to-site lithography correction during exposure after metrology is carried out for every flash field. This system is particularly useful for chiplet consisting of component chips from different technologies and from substrate made of different material. The frames can be further used as part of function component for the packaged system either as electromagnetic shield, or heat dissipation/heat sink, or even RF antenna as well as other passive devices or active components.