Segmented Copper Shield for Semiconductor Adhesion
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Solution Overview
Problem
The adhesion between the copper shield section and the encapsulating resin in semiconductor devices is poor due to differences in thermal expansion coefficients and material properties, leading to peeling and reduced moisture resistance, which deteriorates the reliability of the product.
Innovation Solution
A semiconductor device with a shield section comprising parallel strip metallic thin films connected at their ends or centers, extending to external connecting positions, and encapsulated with resin, which also includes redistribution wirings and metallic posts for electrical and mechanical connections, ensuring better adhesion between the insulating layer and encapsulating resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the area of the copper plating film of the shield section is increased to enhance the shield effect, then the shielding performance is improved, but the adhesion between the shield section and the encapsulating resin is degraded due to poor adhesion between copper and resin, leading to peeling and reduced moisture resistance
Solution Approach 1:
The shield section is divided into multiple discrete copper plating patterns (e.g., grid pattern with lines and spaces) rather than using a continuous copper film. This segmentation reduces the total copper surface area in contact with the encapsulating resin while maintaining effective electromagnetic shielding through the distributed conductive structures.
Solution Approach 2:
The copper plating is applied selectively in specific patterns (such as grid patterns with controlled line widths and spacing) rather than uniformly across the entire shield region. This creates local variations in copper distribution that optimize both shielding effectiveness and adhesion characteristics by reducing continuous copper-resin contact areas.
2Object-affected harmful factors
If a continuous copper plating film is used for the shield section, then the shield effect is enhanced, but the difference in thermal expansion coefficient between copper and encapsulating resin causes peeling and degradation of moisture resistance
Solution Approach 1:
The continuous copper film is replaced with segmented copper plating patterns (such as grid patterns, dashed lines, or isolated patches). This segmentation creates multiple small copper regions instead of one large continuous area, reducing the cumulative thermal stress and preventing large-scale peeling by isolating stress concentration points.
Solution Approach 2:
The copper plating is designed with predetermined patterns and spacing that anticipate thermal expansion stresses. By pre-configuring the copper structures with gaps and discontinuities, the design accommodates thermal expansion differences before stress accumulation can cause peeling, effectively pre-compensating for thermal mismatch issues.
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
This configuration enhances the reliability of the semiconductor device by preventing peeling and improving moisture resistance, maintaining the adhesion between the shield section and encapsulating resin, thus effectively shielding the analog circuit from noise.
Implementation Method 1
a shield section in which a plurality of strip metallic thin films are disposed in parallel at predetermined intervals at spots where the strip metallic thin films are placed over the surface of the insulating layer and on the upper side of the analog circuit
Implementation Method 2
an encapsulating resin which exposes leading ends of the metallic posts and seals side surfaces of the metallic posts, the insulating layer, the redistribution wirings and the shield section
Data Source
AI summary
Strip metallic thin films each having a width of 180 μm or so are disposed in parallel at intervals of 10 μm to 50 μm on the surface of a protection layer formed on the silicon substrate and at their corresponding spots located on the upper side of an analog circuit formed in a silicon substrate. These strip metallic thin films are connected to one another at their ends or centers to form a comb-like shield section and one end thereof is connected to its corresponding external connecting post. Incidentally, the shield section is formed by copper plating in the same process as redistribution wirings that connect electrode pads at an outer peripheral portion of the silicon substrate to their corresponding external connecting posts. Since the encapsulating resin and the protection layer are reliably adhered to each other when the upper portions of the redistribution wirings and the shield section are sealed with the encapsulating resin, the shield section is adhered to the encapsulating resin and has no fear of being peeled therefrom.