Semiconductor Package Seal Ring Layout for Reflow Warpage
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Solution Overview
Problem
The packaging of integrated circuits faces issues with warpage due to elevated temperatures during the reflow process, leading to potential crack or delamination in organic materials, which affects the yield of the packaging process.
Innovation Solution
A semiconductor package is designed with a seal ring structure that includes via features arranged in a discontinuous manner to enhance connection reliability without voids or cracks, using a buffer region between the functional circuit and seal ring regions, and employing a sequence of interconnect layers and via patterns formed through specific processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic materials are used for package components, then ease of lamination is improved, but warpage occurs during reflow process
Solution Approach 1:
The package component is divided into multiple layers including organic material layers and intermediate layers with different material compositions. This segmentation allows each layer to be optimized for its specific function while collectively reducing warpage through controlled thermal expansion differences.
Solution Approach 2:
The patent employs composite material structures combining organic materials with intermediate layers containing inorganic fillers or different polymer matrices. This composite approach maintains the lamination ease of organic materials while adding dimensional stability through the composite structure's controlled thermal properties.
2Reliability
If elevated temperature reflow process is used, then connection reliability is improved, but crack or delamination occurs
Solution Approach 1:
The patent incorporates stress buffer layers and compliant intermediate layers before the reflow process that are designed to absorb and distribute thermal stresses. These layers act as a cushion during the high-temperature reflow, preventing stress concentration that would lead to cracks or delamination while still allowing reliable connections to form.
Solution Approach 2:
The patent modifies material parameters such as glass transition temperature, coefficient of thermal expansion, and viscosity of the organic materials to optimize their behavior during the reflow process. By carefully selecting materials with appropriate parameter ranges, the structure can withstand elevated temperatures without failing while maintaining connection integrity.
3Quantity of substance
If continuous via pattern is used, then connection density is improved, but voids and cracks increase
Solution Approach 1:
The via pattern is segmented into discrete, spaced-apart features rather than continuous traces. This segmentation reduces the total length of potential crack paths and void formation zones while maintaining adequate connection density through optimized via spacing and distribution patterns that concentrate connections where needed.
Data Source
AI summary
A semiconductor package and a manufacturing method thereof are provided. A package substrate of a device includes a functional circuit structure in a central region of the package substrate and a seal ring structure in a peripheral region of the package substrate and electrically isolated from the functional circuit structure. The seal ring structure includes a via pattern including outer discrete features arranged in an outer loop and inner discrete features arranged in an inner loop between the outer loop and the functional circuit structure. In a top view, ends of adjacent two of the inner discrete features are spaced apart from each other by a non-zero distance, and one of the outer discrete features overlaps the non-zero distance.