Protrusion Structure for Underfill Flow in Stacked Electronic Gaps
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Solution Overview
Problem
The challenge in stacked electronic structures is the difficulty in underfill flow due to small spaces between the wiring and package structures, leading to voids that affect reliability and performance, exacerbated by warpage which further restricts underfill flow.
Innovation Solution
Incorporating a protrusion structure in the gap between the circuit pattern and packaging structures to facilitate underfill distribution, utilizing capillary action to ensure complete filling and enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small size solders are used to electrically connect the wiring structure and the package structure, then bridging is prevented, but the space for underfill flow becomes smaller
Solution Approach 1:
The gap between the wiring structure and package structure is segmented into multiple regions by introducing protrusion structures. These protrusions create distinct zones that guide underfill flow from the outer edges toward the center, allowing complete filling even in reduced spaces while maintaining small solder sizes for bridging prevention.
Solution Approach 2:
Protrusion structures are strategically positioned at specific locations within the gap to create localized flow channels. The protrusions have varying heights and distributions optimized for different regions, enhancing underfill penetration in critical areas while preserving overall space constraints for reliable electrical connections.
2Stability of the object's composition
If the space between the wiring structure and package structure is reduced, then warpage effects are minimized, but underfill flow to the center becomes more difficult
Solution Approach 1:
The protrusion structures introduce a vertical dimension element into the horizontal gap space. By creating height variations through protrusions, the solution enables capillary-driven underfill flow to overcome the reduced horizontal space, allowing complete center filling while maintaining compact overall dimensions for warpage control.
Solution Approach 2:
The protrusion structures act as intermediary elements that mediate between the conflicting requirements of reduced gap space and adequate underfill flow. These protrusions create capillary channels that guide and accelerate underfill movement, enabling complete filling in constrained spaces without compromising structural stability.
3Volume of moving object
If the gap between the circuit pattern structure and packaging structure is smaller, then the stacked product size is reduced, but voids are more likely to form
Solution Approach 1:
The protrusion structures are pre-configured in the gap before underfill application. These protrusions create predetermined flow paths and capillary channels that actively guide underfill movement toward the center, preventing void formation from the outset. This preliminary structural arrangement ensures complete filling even in highly compact stacked product designs.
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
The protrusion structure enables effective underfill flow and distribution, preventing voids and enhancing the reliability and performance of the stacked electronic structure.
Implementation Method 1
it is difficult for the underfill to flow to a center of a space between the wiring structure and the package structure through capillary effect
Data Source
AI summary
An electronic structure includes a packaging structure, a circuit pattern structure, an underfill and a protrusion structure. The circuit pattern structure is disposed over the packaging structure. A gap is between the circuit pattern structure and the packaging structure. The underfill is disposed in the gap. The protrusion structure is disposed in the gap, and is configured to facilitate the distributing of the underfill in the gap.