Interposer Package Structure With Slanted Sidewalls Against Cracking
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Solution Overview
Problem
The reliability of multi-die semiconductor packages is compromised due to challenges in packaging materials and their arrangement, leading to issues with thermal and physical stresses, as well as electrical connections, which affect the overall performance and longevity of the packaged products.
Innovation Solution
A manufacturing method involving a carrier with an interposer, semiconductor dies, conductive vias, and a redistribution structure, where a molding compound encapsulates the dies, and a bevel-cutting process forms slanted cut lanes in the interposer to prevent corner cracking and delamination, accompanied by a protection layer to reinforce connectors and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging materials and arrangements are used, then manufacturing simplicity is maintained, but reliability deteriorates due to thermal and physical stresses
Solution Approach 1:
The interposer is segmented with cut lanes formed therein, dividing the rigid interposer structure into sections separated by flexible regions. This segmentation allows the packaging structure to accommodate thermal expansion and contraction differently in various regions, reducing stress concentration and improving overall reliability without requiring a complete redesign of the entire package.
Solution Approach 2:
The packaging structure employs composite materials including the interposer, molding compound, underfill material, and protection layer with different mechanical and thermal properties. These composite materials are arranged in layers with varying coefficients of thermal expansion, creating a gradient structure that mitigates thermal stress while maintaining structural integrity and reliability.
2Manufacturing precision
If rigid packaging structures are used, then manufacturing precision is maintained, but cracking risk increases due to thermal stress
Solution Approach 1:
The interposer is divided by cut lanes into multiple sections, creating flexible joints that can accommodate thermal expansion and contraction. This segmentation maintains precise alignment and positioning of semiconductor components while reducing the risk of cracking by allowing controlled movement at the cut lane regions during thermal cycling.
Solution Approach 2:
The protection layer is applied beforehand to cover and protect the connectors and vulnerable regions of the interposer. This protective layer acts as a cushioning element that absorbs and distributes thermal stress before it can cause cracking, preventing damage during subsequent manufacturing and operation while maintaining the precision of the underlying structure.
3Ease of operation
If connectors are exposed without protection, then electrical connection accessibility is improved, but reliability deteriorates due to corner cracking and delamination
Solution Approach 1:
The protection layer is applied in advance to cover the connectors and surrounding regions of the interposer. This layer provides mechanical protection against corner cracking and delamination while maintaining connector functionality. The protection layer acts as a cushioning element that absorbs stress during thermal cycling and handling, ensuring both accessibility and reliability.
Solution Approach 2:
The protection layer is made of material with different mechanical properties than the interposer and molding compound, creating a composite structure that protects the connectors. This composite arrangement provides both mechanical protection against cracking and delamination while maintaining the electrical connection accessibility needed for operation.
4Ease of manufacture
If uniform packaging structure is used, then manufacturing simplicity is maintained, but thermal stress distribution becomes uneven
Solution Approach 1:
The packaging structure introduces asymmetry through the cut lanes in the interposer, creating regions with different stiffness and thermal expansion characteristics. This asymmetric design allows different parts of the package to expand and contract differently during thermal cycling, distributing thermal stress more evenly throughout the structure rather than concentrating it in uniform regions.
Solution Approach 2:
The package uses composite materials with different coefficients of thermal expansion arranged in layers (interposer, molding compound, underfill, protection layer). This composite structure creates a gradient of thermal properties that distributes thermal stress more uniformly across the package, preventing hot spots and stress concentration while maintaining manufacturability.
Data Source
AI summary
A semiconductor package and a manufacturing method thereof are provided. The semiconductor package includes at least one semiconductor die, an interposer, an encapsulant, a protection layer and connectors. The interposer has a first surface, a second surface opposite to the first surface and sidewalls connecting the first and second surfaces. The semiconductor die is disposed on the first surface of interposer and electrically connected with the interposer. The encapsulant is disposed over the interposer and laterally encapsulating the at least one semiconductor die. The connectors are disposed on the second surface of the interposer and electrically connected with the at least one semiconductor die through the interposer. The protection layer is disposed on the second surface of the interposer and surrounding the connectors. The sidewalls of the interposer include slanted sidewalls connected to the second surface, and the protection layer is in contact with the slant sidewalls of the interposer.