Flip-Chip Substrate Composite Core Warpage Prevention
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Solution Overview
Problem
Current flip-chip package substrates face issues with warpage due to inconsistent thermal expansion coefficients, reduced conductive point density, increased circuit pitch, and poor heat dissipation, which are exacerbated by thickening the core structure to improve rigidity.
Innovation Solution
A flip-chip package substrate with a composite core structure comprising a middle layer made of insulative material and insulation layers made of highly rigid dielectric material, forming conductive structures with small end sizes and high density, and a dual-side built-up circuit structure to enhance rigidity and prevent warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the core structure is thickened to improve rigidity and prevent warpage, then the structural stability is improved, but the conductive point density is reduced and the circuit pitch is increased
Solution Approach 1:
The patent employs a composite core structure consisting of a glass fiber reinforced epoxy resin substrate combined with an organic dielectric material layer. This composite construction provides high rigidity and dimensional stability while maintaining a thin overall profile, thereby preventing warpage without requiring excessive thickness that would reduce conductive point density.
Solution Approach 2:
The patent optimizes the thickness parameters of different layers: the glass fiber reinforced substrate is controlled at 0.1-0.3mm and the organic dielectric layer at 0.05-0.2mm. By precisely controlling these parameters, the substrate achieves sufficient rigidity to prevent warpage while maintaining small hole diameters (0.05-0.15mm) for high conductive point density.
2Stability of the object's composition
If the core structure is thickened to improve rigidity, then the warpage resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent uses a composite structure of glass fiber reinforced epoxy resin and organic dielectric material that inherently provides high rigidity and warpage resistance. This composite design achieves the desired structural stability without requiring complex manufacturing processes or excessive material thickness, simplifying production while maintaining performance.
Solution Approach 2:
The patent applies different materials with specific properties to different functional requirements: the glass fiber reinforced epoxy provides mechanical strength and dimensional stability, while the organic dielectric material provides electrical insulation and surface planarity. This localized material optimization achieves warpage resistance without unnecessary complexity.
3Ease of manufacture
If materials with inconsistent coefficients of thermal expansion are used in the substrate, then the material availability and ease of manufacture are improved, but the connection reliability is reduced due to warpage and poor bonding
Solution Approach 1:
The patent uses a composite core structure where the glass fiber reinforced epoxy resin substrate and organic dielectric material are bonded together. This composite construction provides inherent dimensional stability and reduces warpage, ensuring reliable solder connections while maintaining ease of manufacture with readily available materials.
Solution Approach 2:
The patent controls the thickness of the organic dielectric material layer (0.05-0.2mm) to optimize the thermal expansion characteristics of the composite structure. This parameter control compensates for CTE mismatches between layers, preventing warpage and ensuring reliable connections while using commercially available materials.
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 solution provides a robust, thin flip-chip package substrate with increased conductive point density, improved circuit density, reduced electrical resistance, and enhanced heat dissipation, addressing the challenges of warpage and manufacturing costs while supporting high-integrated semiconductor packaging.
Implementation Method 1
an organic dielectric material layer bonded to the glass fiber reinforced epoxy resin substrate
Implementation Method 2
a plurality of conductive structures, each of which penetrates the middle layer and the insulation layer and is exposed from the first and second sides of the core structure
Data Source
AI summary
A flip-chip package substrate and a method for fabricating the same are provided. An insulation layer is formed on two opposing sides of a middle layer to form a composite core structure and increase the rigidity of the flip-chip package substrate. Therefore, the core structure can be made thinner. The conductive structures can also have a smaller end size, and more conductive points can be disposed within a unit area. Therefore, a circuit structure can be produced that have a fine line pitch and a high wiring density, satisfy the packaging demands of highly integrated circuit/large size substrate, and avoid an electronic package from being warpage.