Diffusion Soldering Cavities for Reliable Electronic Connections
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Solution Overview
Problem
Existing diffusion soldering methods face challenges in ensuring a reliable and mechanically stable connection between electronic components and substrates due to manufacturing tolerances and the need for precise application of solder material, which can lead to incomplete diffusion zones and mechanical instability.
Innovation Solution
The method involves equipping the mounting and contact surfaces with depressions that are filled with solder material, allowing for a sufficient thickness of solder to ensure a diffusion zone forms across the interface, even with manufacturing tolerances, and providing a buffer for excess solder, ensuring a mechanically stable connection with increased melting temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder material is applied with sufficient thickness to ensure complete filling and reliable connection formation, then connection reliability is improved, but manufacturing precision deteriorates due to difficulty in controlling exact application amount and gap variations
Solution Approach 1:
The patent introduces depressions in the mounting surface or contact surface that serve as pre-prepared buffer zones. These depressions are designed to accommodate excess solder material before diffusion occurs, cushioning against variations in solder application thickness and gap size. This allows solder to be applied with sufficient thickness to ensure complete filling without risking overflow or incomplete connection formation, thereby resolving the contradiction between connection reliability and manufacturing precision.
2Manufacturing precision
If manufacturing tolerances are tightened to ensure complete diffusion zone formation, then connection quality is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The depressions are formed as integral parts of either the mounting surface or contact surface during standard manufacturing processes. This pre-formed buffer structure absorbs the impact of manufacturing tolerances in gap size and solder application, allowing diffusion zones to form completely even with moderate tolerance variations. This eliminates the need for tight tolerance specifications and complex manufacturing processes, thereby resolving the contradiction between connection quality and manufacturing complexity.
3Reliability
If solder material is applied in excess to ensure complete gap filling, then connection completeness is improved, but heat dissipation efficiency deteriorates due to potential solder overflow and increased thermal resistance
Solution Approach 1:
The patent applies the principle of local quality by creating depressions only in specific locations where excess solder material needs to be contained. The depressions are strategically positioned to capture overflow solder without affecting the thermal path of the diffusion zone. This localized approach allows excess solder to be accommodated in non-critical areas while maintaining efficient heat dissipation through the properly formed diffusion connection, thereby resolving the contradiction between connection completeness and heat dissipation efficiency.
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 approach enables the formation of a reliable and thermally stable diffusion-soldered connection with increased melting temperature, ensuring mechanical stability and efficient heat dissipation, while reducing manufacturing complexity and tolerancing issues.
Implementation Method 1
the solder material is heated to a temperature which initiates a diffusion process between the solder material and the component and between the solder material and the substrate
Implementation Method 2
the diffusion zone may, in the case of a solder material comprising tin, be formed for example by the intermetallic compound of copper and tin
Implementation Method 3
The solder material may be liquefied, because in this way, the diffusion processes in the solder material can be greatly accelerated
Implementation Method 4
the mounting and contact surfaces with depressions that act as buffers for excess solder material
Data Source
AI summary
A diffusion soldering method for joining an electronic component to a substrate is provided. The joining surfaces are designed such that cavities are formed in a joining gap between the component and substrate. The formation of such cavities can be provided, e.g., by depressions in a mounting surface of the component and/or in a contact surface of the substrate, the depressions being cup-shaped and/or defining channels that surround columnar structural elements, the end faces of which define the mounting surface and/or contact surface. The cavities are designed such that solder material can leak into the cavities when the component during a heating process to achieve a desired width of the joining gap. This allows for the formation of a narrow-width joining having a diffusion zone that bridges the joining gap upon soldering. In this manner, a diffusion solder connection can be produced even using standard solder.