Semiconductor Package Fillet Layer Control With Side Trenches
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Solution Overview
Problem
Semiconductor packages with multiple chips face issues such as frequent defects and reliability degradation due to cracks, primarily caused by excessive fillet layer protrusion from the chip edges, which can lead to mechanical stress and failure.
Innovation Solution
The semiconductor package design incorporates side trenches and corner trenches in the protective layer to control the fillet layer's distribution, reducing its protrusion from the chip edges and enhancing the package's reliability by ensuring a denser fillet layer fill between the substrate and the chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple semiconductor chips are placed within a single package in a stacked structure, then the package size is reduced and functionality is diversified, but cracks and reliability degradation occur due to excessive fillet layer protrusion
Solution Approach 1:
The protective layer is segmented into multiple regions: a first region with a first depth, a second region with a second depth greater than the first depth, and a third region with a third depth greater than the second depth. This segmentation creates varying trench depths to control fillet layer distribution at different locations, preventing excessive protrusion while maintaining package compactness
Solution Approach 2:
Different regions of the protective layer are given different local qualities through varying trench depths. The first region (shallower) allows more fillet layer, the second region (intermediate depth) allows moderate fillet layer, and the third region (deepest) allows minimal fillet layer. This local differentiation prevents cracks at critical areas while maintaining overall package integrity
2Strength
If the fillet layer is allowed to fill the space between the protective layer and semiconductor chip, then structural support is improved, but excessive protrusion from chip edges causes mechanical stress and failure
Solution Approach 1:
Trenches are formed in the protective layer before the fillet layer is applied. These pre-formed trenches act as barriers that guide and limit fillet layer flow, preventing excessive protrusion from occurring in the first place rather than correcting it afterward
Solution Approach 2:
The trenches, which initially seem to reduce the filling space, actually benefit the structure by preventing harmful fillet layer protrusion. The reduced fillet layer volume in certain regions converts what would be a harmful protrusion into a beneficial controlled distribution, eliminating mechanical stress while maintaining structural support
Data Source
AI summary
A semiconductor package includes a base substrate having a first semiconductor substrate, and a first protective layer covering a top side thereof. A first semiconductor chip is on the first protective layer. A first fillet layer fills a space between the first protective layer and the first semiconductor chip. A first side surface of the base substrate extends in a first direction, and second and third side surfaces extend in a second direction. The base substrate includes two corner regions and a side region between the corner regions. A first protective layer in the side region includes a first side trench which overlaps the first semiconductor chip. A part of the first fillet layer fills the first side trench.