Barrier Metal Bonding Structure for Void-Resistant Electronic Assembly
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Solution Overview
Problem
Existing electronic devices face issues with reduced reliability due to insufficient bonding strength and electrical conductivity caused by defects such as voids and excessive wetting of bonding layers, which are exacerbated by the direct contact of bonding layers with the wiring layer.
Innovation Solution
The implementation of barrier metals between the wiring layer and bonding layers, along with the fusion of plating layers during the bonding process, ensures adequate thickness and minimizes void formation, thereby enhancing bonding strength and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bonding layers directly contact the wiring layer, then the manufacturing process is simpler, but bonding strength and electrical conductivity are insufficient due to voids and excessive wetting
Solution Approach 1:
A barrier metal layer is introduced as an intermediary between the bonding layer and the wiring layer. This barrier metal prevents direct contact between the bonding layer and wiring layer, controlling the wetting process and preventing excessive spread that causes voids. The barrier metal serves as a mediator that maintains adequate bonding layer thickness while still enabling reliable electrical connection through the plating layer fusion process.
Solution Approach 2:
The invention changes the physical and chemical parameters of the bonding interface by introducing the barrier metal with specific material properties. The barrier metal has controlled surface energy and reactivity parameters that regulate the wetting behavior of the bonding layer, preventing both excessive wetting (which causes voids) and insufficient wetting (which reduces bonding strength). This parameter control ensures adequate bonding layer thickness is maintained.
2Device complexity
If bonding layers directly contact the wiring layer, then the device structure is less complex, but electrical conductivity is reduced due to defects and insufficient bonding
Solution Approach 1:
The barrier metal acts as an intermediary layer that ensures reliable electrical conductivity by controlling the interface between the bonding layer and wiring layer. It prevents defect formation (voids) that would disrupt electrical current flow, while the plating layer fusion process maintains low-resistance electrical pathways. The barrier metal's controlled presence actually simplifies the electrical performance by eliminating conductivity-destroying defects.
3Reliability
If barrier metals are introduced between wiring layer and bonding layers, then bonding strength and electrical conductivity are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The bonding interface is segmented into multiple functional layers: the barrier metal layer for wetting control and void prevention, and the plating layer for electrical conductivity and bonding strength. This segmentation allows each layer to perform its specific function optimally, with the barrier metal preventing defects and the plating layer providing strong, conductive bonding. The segmented structure actually simplifies the overall reliability by assigning specific functions to specific layers.
4Reliability
If barrier metals are introduced between wiring layer and bonding layers, then void formation is minimized and bonding layer thickness is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The barrier metal layer introduces controlled physical and chemical parameters that regulate the bonding process. Its surface energy, thickness, and material composition are optimized to control wetting behavior, ensuring the bonding layer spreads appropriately without forming voids. These parameter changes create a more forgiving manufacturing process by preventing defect formation through material property control rather than relying solely on precise geometric alignment.
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 effectively suppresses defects in bonding layers, maintaining reliability by preventing voids and ensuring sufficient bonding strength and electrical conductivity, thus improving the overall performance of the electronic device.
Implementation Method 1
a bonding step of bonding the electronic component by melting the bonding layer by reflow and cooling and solidifying the melted bonding layer
Data Source
AI summary
An electronic device includes a support member, a wiring layer, a barrier metal, a bonding layer, and an electronic component. The support member includes an obverse surface facing a side in a thickness direction. The wiring layer is formed on the obverse surface. The barrier metal is formed on the wiring layer. The bonding layer is formed on the barrier metal. The electronic component is bonded to the wiring layer via the bonding layer and the barrier metal, and is electrically connected to the wiring layer. The barrier metal and the wiring layer contain mutually different metals. The barrier metal is smaller than the wiring layer as viewed in the thickness direction.