Semiconductor Package Metal Layer Adhesion via Surface Roughness
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Solution Overview
Problem
The existing semiconductor packages face challenges in achieving strong adhesion between the metal layer and the encapsulant in the upper portion of a semiconductor chip, which complicates the manufacturing process and can lead to degraded performance in electromagnetic interference shielding and heat dissipation.
Innovation Solution
A semiconductor package design that incorporates a first conductive layer with surface roughness in contact with the encapsulant, followed by a second conductive layer with smoother surface roughness, enhancing adhesion and simplifying the manufacturing process by using a copper foil layer as a seed layer for electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a chemical copper layer is formed after removing a carrier from an encapsulant, then a metal layer can be disposed on the encapsulant, but adhesion between the encapsulant and the chemical copper layer is degraded and the process becomes complicated
Solution Approach 1:
The patent applies preliminary action by forming a roughened surface layer on the encapsulant before depositing the metal layer. This roughening treatment is performed in advance to create surface irregularities that will mechanically interlock with the subsequent metal layer, ensuring strong adhesion from the outset and eliminating the need for complex chemical copper formation processes later.
Solution Approach 2:
The patent changes the surface parameter of the encapsulant by intentionally creating surface roughness. This parameter change transforms the smooth encapsulant surface into a rough surface with increased surface area and mechanical interlocking capability, which significantly improves adhesion to the metal layer while simplifying the overall manufacturing process.
2Ease of manufacture
If the metal layer is formed with smooth surface, then the manufacturing process is simplified, but adhesion between the metal layer and encapsulant is degraded
Solution Approach 1:
The patent applies local quality by creating a dual-layer metal structure where the first metal layer has a rough surface for strong adhesion to the encapsulant, while the second metal layer has a smooth surface for ease of manufacture and subsequent processing. This local differentiation of surface quality allows each layer to optimize its specific function.
Solution Approach 2:
The patent uses composite materials by combining two metal layers with different surface characteristics. The first metal layer provides rough surface adhesion, while the second metal layer provides smooth surface properties. This composite structure achieves both strong adhesion and manufacturing simplicity that neither single layer could provide alone.
3Ease of manufacture
If a single metal layer is used on the encapsulant, then the manufacturing process is simplified, but electromagnetic interference shielding and heat dissipation performance are insufficient
Solution Approach 1:
The patent applies segmentation by dividing the metal layer into multiple distinct layers, each performing specific functions. The first metal layer provides adhesion and rough surface characteristics, while the second metal layer provides smooth surface characteristics and contributes to EMI shielding and heat dissipation. This segmentation allows optimization of each layer's properties for its specific function.
Solution Approach 2:
The patent achieves multi-functionality by designing a multi-layer metal structure that simultaneously provides adhesion, EMI shielding, and heat dissipation functions. The combination of rough and smooth surface layers creates a system that performs multiple functions that a single layer could not achieve alone.
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 design improves the adhesion between the metal layer and the encapsulant, simplifies the manufacturing process, and enhances the package's performance in electromagnetic interference shielding and heat dissipation, making it suitable for miniaturized and thinned semiconductor packages.
Implementation Method 1
A lower surface of the first conductive layer is in contact with the first encapsulant and has first surface roughness
Implementation Method 2
a first conductive layer with surface roughness in contact with the encapsulant, followed by a second conductive layer with smoother surface roughness, enhancing adhesion and simplifying the manufacturing process by using a copper foil layer as a seed layer for electroplating
Data Source
AI summary
A semiconductor package includes a semiconductor chip having an active surface on which a connection pad is disposed and an inactive surface opposing the active surface, and a first encapsulant covering at least a portion of each of the inactive surface and a side surface of the semiconductor chip. A metal layer is disposed on the first encapsulant, and includes a first conductive layer and a second conductive layer, sequentially stacked. A connection structure is disposed on the active surface of the semiconductor chip, and includes a first redistribution layer electrically connected to the connection pad. A lower surface of the first conductive layer is in contact with the first encapsulant and has first surface roughness, and an upper surface of the first conductive layer is in contact with the second conductive layer and has second surface roughness smaller than the first surface roughness.