Mo Barrier Solder Bonding Structure for Reflow Interface Strength
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Solution Overview
Problem
Existing electronic devices face a decrease in interface strength of solder bonding portions due to metal reactions during high temperature processes like reflow bonding, leading to mechanical deterioration and potential cracking.
Innovation Solution
Incorporating a barrier layer made of Mo as the main component, accompanied by a bonding layer containing Ni, Ag, Au, or Cu, to reduce metal reactions and maintain interface strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple electrode structure is used, then manufacturing is easier, but interface strength decreases due to metal reactions during high temperature processes
Solution Approach 1:
The bonding portion is segmented into three distinct layers: barrier layer (Mo), bonding layer (Ni/Ag/Au/Cu), and solder layer. This segmentation allows each layer to perform its specific function - the barrier layer prevents metal reactions, the bonding layer provides bonding capability, and the solder layer enables soldering, thereby resolving the contradiction between manufacturing simplicity and interface strength
Solution Approach 2:
The bonding portion uses a composite structure of multiple metal layers with different properties. The barrier layer (Mo) provides oxidation resistance, the bonding layer (Ni/Ag/Au/Cu) provides bonding strength, and the solder layer provides solderability. This composite material approach maintains interface strength while preventing harmful metal reactions during high temperature processes
2Productivity
If high temperature processes like reflow bonding are performed, then soldering is achieved, but metal reactions occur causing mechanical deterioration and cracking
Solution Approach 1:
The barrier layer acts as an intermediary between the electrode and the bonding layer, preventing direct contact and chemical reactions between metals during high temperature processes. This intermediary layer allows the high temperature soldering process to proceed while blocking the harmful metal reactions that would otherwise cause mechanical deterioration and cracking
Solution Approach 2:
The barrier layer is applied in advance before soldering to prevent metal reactions. By establishing this protective layer beforehand, the patent prevents the harmful chemical reactions between electrode metals and solder metals during the high temperature reflow bonding process, thereby maintaining reliability while enabling productive soldering
Data Source
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AI summary
To secure sufficient interface strength in a solder bonding portion even after going through a high temperature process such as reflow bonding. A device has a base, an electrode comprising Ni and Cu, and a bonding portion located on the electrode. The bonding portion includes a barrier layer, a bonding layer, and a solder layer in this order from the electrode side. The barrier layer contains Mo as a main component, and the bonding layer contains at least one of Ni, Ag, Au, and Cu.