Sealing Cap Non-Flat Surface Brazing Control
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Solution Overview
Problem
Existing sealing caps with cavities face challenges in suppressing wet-spreading of brazing material during sealing, and conventional Au plating methods are inefficient in reducing the amount of gold used, which is a precious and costly resource.
Innovation Solution
The cap features a brazing material-fused surface with a non-flat, three-dimensional work surface, increasing its surface area relative to the sealing surface, allowing controlled flow and reduced Au plating by applying Au only where needed, with a surface area ratio of 1<Sc/Sf≤1.6, and incorporating features like grooves, slopes, and protrusions to inhibit wet-spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Au plating is applied on the cap surface to ensure wettability of brazing material, then wettability is improved, but the amount of Au plating cannot be reduced due to cost considerations
Solution Approach 1:
The invention applies Au plating only on specific local areas where it is actually needed for brazing material fusion, rather than uniformly across the entire cap surface. The brazing material-fused surface is designed with a non-flat work surface that concentrates the Au plating application to regions where brazing occurs, thereby reducing overall Au consumption while maintaining necessary wettability for reliable bonding.
Solution Approach 2:
The cap is designed with a pre-formed non-flat work surface structure before Au plating is applied. This preliminary structural design creates specific geometric features (protrusions, recesses, inclined surfaces) that guide and control the subsequent Au plating process, ensuring Au is deposited only where needed for brazing, thus reducing total Au usage while ensuring wettability where required.
2Ease of manufacture
If the brazing material-fused surface is made flat, then manufacturing is simple, but the brazing material flows and spreads excessively during sealing
Solution Approach 1:
The invention replaces the flat brazing material-fused surface with a non-flat work surface featuring curved geometric elements such as protrusions, recesses, and inclined surfaces. These curved features create a three-dimensional topology that physically restricts the flow and spreading of molten brazing material during sealing, preventing excessive wet-spreading while maintaining manufacturability through standard forming processes.
Solution Approach 2:
The invention transitions from a two-dimensional flat surface to a three-dimensional non-flat work surface by adding vertical dimensionality through protrusions, recesses, and inclined surfaces. This dimensional change creates physical barriers and flow paths that control brazing material movement, suppressing harmful wet-spreading while preserving ease of manufacture through conventional forming techniques.
3Object-generated harmful factors
If a non-flat work surface is formed on the brazing material-fused surface to suppress wet-spreading, then wet-spreading is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The non-flat work surface is designed with smooth curved features (protrusions, recesses, inclined surfaces) that can be formed using standard manufacturing processes such as die-forming, stamping, or molding. These curved geometric elements provide effective wet-spreading suppression through their three-dimensional topology while remaining compatible with conventional manufacturing methods, thus limiting the increase in manufacturing complexity.
4Loss of substance
If the surface area of the brazing material-fused surface is increased relative to the sealing surface, then Au plating amount is reduced, but the surface area ratio must be precisely controlled
Solution Approach 1:
The invention optimizes the surface area ratio (Sc/Sf) between the brazing material-fused surface and sealing surface to a specific range (1.2 ≤ Sc/Sf < 1.6) that balances Au plating reduction with manufacturing feasibility. By establishing this quantitative parameter range, the invention provides clear design guidelines that enable manufacturers to achieve Au savings while maintaining reasonable manufacturing precision without requiring extremely tight tolerances.
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 effectively suppresses wet-spreading of the brazing material and reduces Au plating while ensuring sufficient wettability, resulting in improved airtight sealing and cost savings by minimizing Au usage.
Implementation Method 1
the brazing material may possibly be wet-spread and flow onto the surface of the base
Implementation Method 2
Au plating is typically applied on the surface of the cap
Implementation Method 3
the brazing material is fused and fixed onto the cap in advance; the base is covered with the cap when the sealing work is performed; and the brazing material is melted again for bonding
Data Source
AI summary
An electronic component cap for producing a package having a sealed region by being bonded to a base, having a brazing material-fused surface to which a brazing material is fused and a sealing surface corresponding to the sealed region. The brazing material-fused surface has a non-flat work surface formed by plastic working, and a ratio (Sc/Sf) of a surface area (Sc) of the brazing material-fused surface per unit area to a surface area (Sf) of the sealing surface per unit area satisfies 1<Sc/Sf≤1.6. The cross-sectional shape of the work surface may be one of various shapes such as a groove shape, an approximately V shape, and a circular-arc shape. The cap has a good wettability when a brazing material is fused. Also, the brazing material does not wet-spread excessively when the brazing material is melted again for sealing work.