Closed Chamber Diffusion Soldering for Oxidation Control
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Solution Overview
Problem
Open heating channels in diffusion soldering processes do not allow for the use of aggressive media to reduce oxidized surfaces, leading to incomplete solder formation and mechanical instability due to premature melting and uncontrolled alloy formation, especially at high operating temperatures.
Innovation Solution
A closed evacuated chamber with a combined transfer and pressing unit that includes a rotatable element to precisely place and press components on substrates, allowing for the use of aggressive media like formic acid to activate surfaces and maintain a controlled environment for diffusion soldering, minimizing oxidation and ensuring uniform contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If open heating channels are used for diffusion soldering, then the process is simple and accessible, but aggressive media cannot be used to reduce oxidized surfaces
Solution Approach 1:
The patent employs a closed heating channel that creates an inert or controlled atmosphere environment, allowing aggressive reducing media (such as formic acid vapor) to be introduced without contamination from external air. This enables effective reduction of oxidized surfaces while maintaining process control, resolving the contradiction between accessibility and surface activation capability.
2Reliability
If aggressive media are used to reduce oxidized surfaces, then surface activation is improved, but oxidation control becomes more difficult
Solution Approach 1:
The closed heating channel system creates a controlled inert atmosphere that prevents oxidation during the diffusion soldering process. By sealing the heating channel, the system can introduce aggressive reducing media for surface activation while simultaneously preventing oxygen ingress that would cause oxidation, thus resolving the contradiction between surface activation and oxidation control.
Solution Approach 2:
The closed heating channel enables continuous protection against oxidation throughout the entire diffusion soldering process. The sealed environment maintains consistent atmospheric conditions, allowing aggressive media to act on surfaces without interruption or loss of protective atmosphere, ensuring continuous surface activation and oxidation prevention.
3Object-affected harmful factors
If diffusion soldering is performed without aggressive media, then oxidation is minimized, but solder formation is incomplete and mechanically unstable
Solution Approach 1:
The closed heating channel creates an inert atmosphere that simultaneously achieves two objectives: it prevents oxidation of surfaces during heating, and it allows aggressive reducing media to be introduced for effective surface activation. This resolves the contradiction by providing a controlled environment where both low oxidation and complete solder formation can occur.
Solution Approach 2:
The closed heating channel acts as an intermediary system that mediates between the need for aggressive media (for complete solder formation) and the need to prevent oxidation. By providing a sealed controlled atmosphere, it enables the introduction of reducing media while blocking oxygen, thus facilitating both surface activation and oxidation prevention simultaneously.
4Stability of the object's composition
If the opening surface is small to maintain homogeneous gas flow, then protective gas flow is maintained, but the discharge of protective gas slightly disrupts the flow
Solution Approach 1:
The closed heating channel system creates a sealed inert atmosphere that eliminates gas flow disruption issues. By closing the heating channel, the system maintains homogeneous protective gas flow without the disturbances caused by openings or discharges, ensuring stable atmospheric conditions throughout the diffusion soldering process.
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 solution enables the formation of high-melting intermetallic phases with reduced oxidation, enhancing the thermal stability and reliability of solder connections by minimizing premature melting and ensuring complete alloy formation, thus improving the longevity of semiconductor devices under operating temperatures.
Implementation Method 1
diffusion soldering in a closed evacuated chamber
Implementation Method 2
heat is introduced into the substrates and the solder is remelted
Implementation Method 3
a flowing forming and protective gas atmosphere and a contact pressure are present for a period of time
Implementation Method 4
the use of aggressive media as an activating atmosphere for the reduction of oxidized surfaces
Implementation Method 5
Diffusion soldering provides an alternative technology to soft-soldering
Data Source
AI summary
An apparatus for connecting a component with a substrate by means of diffusion soldering in a closed evacuated chamber is disclosed. The component and the substrate to be connected are displaceable separate from one another in the chamber, and the chamber comprises a combined transfer and pressing unit being displaceable between the current position of the component and the current position of the substrate, for placing and pressing the component on the substrate. The combined transfer and pressing unit comprises a rotatable element, which, in response to the placing and pressing of the component on the substrate, assumes an angle between the normal of the lower side of the component to be connected and the pressing direction of the component, the angle corresponding to the angle between the normal of the substrate surface area to be connected and the pressing direction of the component.