Package Underfill Dam Structure for 3D-IC Delamination Control
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Solution Overview
Problem
3D-IC packages face manufacturing challenges due to delamination issues in the underfill layer, leading to cracks along the interface between the package component and the underfill layer, which affects the quality and integration density of semiconductor devices.
Innovation Solution
A method involving the formation of a dam structure over a substrate, followed by the creation of an underfill layer between the dam structure and the package component, with the dam structure being easily removable after the underfill layer is formed, controlling its size and profile to mitigate delamination problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the underfill layer is formed without a dam structure, then the manufacturing process is simpler, but delamination and cracks occur along the interface between the package component and the underfill layer
Solution Approach 1:
A dam structure is introduced as an intermediary element between the package component and the underfill layer. This dam structure serves as a mold or constraint that controls the flow and positioning of the underfill layer during the bonding process, preventing delamination and interface cracks while maintaining manufacturing feasibility
2Productivity
If the package size is reduced to improve integration density, then more components can be integrated, but manufacturing challenges and delamination issues increase
Solution Approach 1:
The dam structure provides localized control over the underfill layer in critical areas. By confining the underfill layer within the dam structure boundaries, precise control is achieved where needed (at the interface between package component and underfill) while allowing flexibility elsewhere, enabling high integration density without sacrificing manufacturing precision
3Reliability
If a permanent dam structure is used to control underfill layer, then delamination is prevented, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The dam structure is designed as a temporary, disposable element that is discarded after serving its purpose. It is removed after the underfill layer is formed and bonded, leaving no trace in the final product. This approach provides the manufacturing benefits of a controlled underfill layer formation while avoiding the complexity of permanent dam structures
Data Source
AI summary
A method for forming a package structure is provided. The method includes bonding a package component to a substrate through a plurality of first connectors. The package component comprises a first semiconductor die and a second semiconductor die. The method also includes forming a dam structure over the substrate and surrounding the first connectors. A top surface of the dam structure is lower than a bottom surface of the package component. The method further includes filling an underfill layer in a space between the dam structure and the first connectors. In addition, the method includes removing the dam structure after the underfill layer is formed.