Organic Preservative Films for Copper Bump Oxidation
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Solution Overview
Problem
The formation of oxide layers on metal bumps in solder joint structures degrades the reliability of solder joints, and while noble metals can prevent this, they increase material and fabrication costs.
Innovation Solution
The use of preservative films, specifically organic materials like nitrogen-containing compounds, metal-nitrogen compounds, and metal-azole compounds, are applied to inhibit oxide formation on metal bumps, such as copper, by forming a protective barrier on their surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metals are used to prevent oxide layer formation on metal bumps, then the reliability of solder joint structures is improved, but the material cost and fabrication cost increase
Solution Approach 1:
The patent replaces expensive noble metals with a cheap organic preservative film that can be applied as a temporary protective layer. The film is cost-effective and serves its protective function during storage and transport, then can be removed or degraded during soldering process, eliminating the need for costly noble metal materials while maintaining solder joint reliability
Solution Approach 2:
The patent changes the material parameter from noble metals to organic compounds with specific chemical properties. The preservative film uses organic materials containing nitrogen-containing groups (such as amino, imino, or azole groups) that can chemically interact with metal surfaces to prevent oxidation, providing a cost-effective alternative with comparable protective performance
2Reliability
If noble metals are used to prevent oxide layer formation on metal bumps, then the reliability of solder joint structures is improved, but the fabrication process complexity increases
Solution Approach 1:
The preservative film is designed as a temporary protective layer that simplifies the fabrication process. Unlike noble metals that require precise deposition control, the organic film can be applied through simpler methods such as dip-coating or spray application, reducing fabrication process complexity while providing effective oxidation protection
Solution Approach 2:
The organic preservative film acts as an intermediary layer between the metal bump and the oxidizing environment. This intermediate protective layer prevents direct contact between oxygen and the metal surface, eliminating the need for complex noble metal deposition processes while achieving the same protective effect
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
These preservative films effectively prevent oxide formation, ensuring stable physical and electrical interaction between metal bumps and soldering units, thereby enhancing the reliability of electronic devices without the need for costly noble metals.
Implementation Method 1
forming a protective barrier on their surfaces
Implementation Method 2
the preservative film includes one or more organic metal compounds (e.g., a metal-nitrogen compound, a metal-imino compound, a metal-amino compound, a metal-benzotriazole compound and/or a metal-imidazole compound)
Data Source
AI summary
The inventive concept provides methods for inhibiting the formation of one or more oxides on metal bumps during the formation of solder joint structures and solder joint structures including one or more preservative films. In some embodiments, the solder joint structure includes a metal bump having a preservative film disposed on the surface thereof.