Height-Adjusted Molding Member for IC Package Reliability
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Solution Overview
Problem
The height difference between the polymer layer and the molding compound in integrated circuit manufacturing leads to fragile redistribution lines that are prone to breaking during temperature cycling, posing challenges in configuring lines with fine widths and thin thicknesses.
Innovation Solution
A molding member is formed with a top surface higher than the semiconductor substrate, reducing the step height between the molding member and the polymer layer, and extending over the edge of the semiconductor substrate to create a hooking structure, which seals the edge portion and reduces stress, thereby enhancing the reliability and yield of the package structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a height difference is present between the polymer layer and the molding compound, then the manufacturing process is simplified, but the redistribution lines are easily broken during temperature cycling
Solution Approach 1:
The molding member is formed with a top surface higher than the top surface of the polymer layer before the redistribution circuit structure is formed. This preliminary height adjustment prevents the formation of large step differences that would cause redistribution line breakage during subsequent temperature cycling.
Solution Approach 2:
The molding member is configured with different heights at different locations: the top surface is higher than the polymer layer to reduce step height, while extending over the edge of the semiconductor substrate to create a hooking structure. This localized height variation addresses both reliability and manufacturing considerations.
2Productivity
If the redistribution lines are configured with fine width and thin thickness, then the circuit density is improved, but the lines become more fragile and prone to breaking
Solution Approach 1:
The molding member extends over the edge of the semiconductor substrate to create a hooking structure that provides mechanical support and stress relief for the redistribution lines. This cushioning effect protects fine and thin redistribution lines from breaking during temperature cycling by reducing stress concentration at critical interfaces.
3Ease of manufacture
If the molding member top surface is lower than the polymer layer, then the manufacturing process is conventional, but the step height causes stress concentration and delamination
Solution Approach 1:
Instead of forming the molding member top surface lower than the polymer layer as in conventional processes, the invention inverts this approach by forming the molding member top surface higher than the polymer layer. This inversion reduces the step height and prevents stress concentration that leads to delamination at the interface.
Data Source
AI summary
Package structures and methods of forming the same are disclosed. A package structure includes a die, a molding member and a redistribution circuit structure. The die includes a semiconductor substrate, a connector and a passivation layer. The semiconductor substrate has a top surface. The connector is disposed over the top surface of the semiconductor substrate. The passivation layer is disposed over the top surface of the semiconductor substrate and exposes a portion of the connector. The molding member laterally surrounds the semiconductor substrate, wherein a top surface of the molding member is higher than the top surface of the semiconductor substrate and the molding member forms a hooking structure that embraces over an edge portion of the semiconductor substrate. The redistribution circuit structure extends over the passivation layer and the molding member, and is electrically connected to the connector.