RDL Substrate Trench Layout for Edge Stress Isolation
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Solution Overview
Problem
Conventional semiconductor packaging technologies face challenges in accommodating increasingly smaller dies with higher I/O pad densities, leading to packaging difficulties and yield reductions due to limited I/O pad pitch and potential solder bridge issues.
Innovation Solution
The implementation of a Redistribution Line (RDL) structure with a trench defined proximate to axial edges, which separates the active RDL portion from a pillar portion, allowing stresses from packaging housings to be absorbed by the pillar without damaging the active RDL area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fan-in packaging is used with smaller dies, then throughput and cost are improved, but the number of I/O pads is limited and solder bridges may occur
Solution Approach 1:
The patent transitions from fan-in packaging (I/O pads confined to die surface) to fan-out packaging (I/O pads redistributed to larger area beyond die boundaries). This dimensional expansion allows significantly more I/O pads to be accommodated while maintaining larger pad pitches, eliminating solder bridge issues and enabling higher productivity without sacrificing I/O capacity.
2Quantity of substance
If I/O pad pitch is decreased to increase pad density, then the number of I/O pads is increased, but solder bridges may occur
Solution Approach 1:
By redistributing I/O pads to a larger area through fan-out packaging, the patent maintains larger pad pitches while accommodating more total pads. This spatial redistribution in additional dimensions prevents solder bridges from forming between adjacent pads, simultaneously increasing pad quantity and maintaining reliability.
3Reliability
If known-good-dies are packaged after sawing, then reliability is improved, but only fan-out packages are possible with limited area
Solution Approach 1:
The patent combines the benefits of both approaches by implementing fan-out packaging that redistributes I/O pads to a larger area beyond the die boundaries. This allows known-good-die selection to be maintained while simultaneously expanding the effective I/O pad area, resolving the limitation of confined pad placement in traditional fan-in designs.
4Ease of manufacture
If I/O pads are confined to die surface area, then manufacturing is simplified, but the number of solder balls is limited
Solution Approach 1:
The patent expands the I/O pad placement area from the die surface to a larger footprint through fan-out packaging. This dimensional expansion allows more solder balls to be accommodated while maintaining manageable manufacturing processes, effectively increasing capacity without proportionally increasing manufacturing complexity.
Data Source
AI summary
A package comprises at least one first device die, and a redistribution line (RDL) structure having the at least one first device die bonded thereto. The RDL structure comprises a plurality of dielectric layers, and a plurality of RDLs formed through the plurality of dielectric layers. A trench is defined proximate to axial edges of the RDL structure through each of the plurality of dielectric layers. The trench prevents damage to portions of the RDL structure located axially inwards of the trench.