Underfill Trenches for Electronic Device Package
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Solution Overview
Problem
The existing underfill techniques in electronic device packaging result in a significant 'keep out zone' (KOZ) on the substrate surface, which is inefficient and wasteful, as the underfill material flows beyond the necessary area, limiting the placement density and increasing package size and cost.
Innovation Solution
The introduction of trenches on the substrate with 'sharp' edges to confine and control the flow of underfill material, minimizing the KOZ by pinning the contact line and containing the underfill within designated boundaries, thereby reducing unnecessary material usage and optimizing substrate utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If underfill material is dispensed to fill the component-substrate gap, then the gap is filled and attachment joints are strengthened, but the material flows away from the component across the substrate surface forming an extended fillet that wastes material and creates a keep out zone
Solution Approach 1:
The patent extracts the harmful extended fillet formation by introducing trenches that remove the substrate surface area where the fillet would form. The trenches are filled with a material that prevents underfill from spreading beyond the component edges, thus taking out the source of material waste while preserving the beneficial underfill flow into the gap.
Solution Approach 2:
The substrate surface is segmented into functional zones by introducing trenches that divide the continuous surface into discrete areas. These trenches create boundaries that segment the underfill flow path, confining it to the gap region and preventing uncontrolled spread across the entire substrate surface.
2Reliability
If underfill material flows freely across the substrate surface, then the attachment joints are protected, but the keep out zone area increases reducing component placement density
Solution Approach 1:
The patent removes the unnecessary extended fillet region by extracting the substrate surface area beyond the component edges through trench formation. This extraction eliminates the keep out zone while maintaining the protective function of underfill within the gap, thus recovering valuable substrate surface area for additional component placement.
3Reliability
If more underfill material is used to ensure complete gap filling, then the underfill reliability is improved, but the material cost and waste increase
Solution Approach 1:
The patent extracts the wasted material consumption by introducing trenches that prevent underfill from flowing beyond the component edges. By removing the extended fillet formation zone, the trenches ensure that underfill material is directed solely into the gap region, completing the filling function without excessive material consumption.
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 approach effectively minimizes the underfill KOZ, allowing for increased package layout density, reduced size, and lower costs by precisely controlling the underfill geometry and preventing unwanted flow, thus enhancing the reliability and efficiency of electronic device packaging.
Implementation Method 1
Capillary underfill typically involves flowing an adhesive material between the component and the substrate, so that it contacts both the component and the substrate as it is drawn into and through an intervening gap by a wicking action.
Implementation Method 2
flowing an adhesive material between the component and the substrate, so that it contacts both the component and the substrate
Data Source
AI summary
Electronic device package technology is disclosed. In one example, an electronic device package can include a substrate having a top surface and a vertical surface extending downward from the top surface. The top surface and the vertical surface can define an edge. The electronic device package can also include an electronic component disposed on the top surface of the substrate and electrically coupled to the substrate. In addition, the electronic device package can include an underfill material disposed at least partially between the electronic component and the top surface of the substrate. A lateral portion of the underfill material can extend from the electronic component to at least the edge. Associated systems and methods are also disclosed.