Self-Assembly Bonding via Solid Metal Coating Phase Transition
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Solution Overview
Problem
The existing self-assembly methods for bonding components to a substrate using solder contacts face issues with premature dewetting and solidification due to metallization layer dissolution and mismatched melting points, leading to unreliable bonds.
Innovation Solution
A method where solder is formed on the substrate with a desired component arrangement, melting and solidifying without temperature reduction, using solid metal coatings that form a liquid phase upon contact, preventing premature degradation and ensuring a reliable bond through surface tension and diffusion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the medium is heated to melt solder contacts for self-assembly, then the solder contacts become liquid and can wet the bond metallisations, but the metallisation layers dissolve completely and the solder dewets or solidifies prematurely
Solution Approach 1:
The invention changes the temperature parameter from high (melting solder) to moderate (below solder melting point), and changes the solder state from solid to liquid by dissolving it in the liquid medium. This allows the solder to wet metallisations without causing excessive dissolution or premature solidification.
Solution Approach 2:
The liquid medium acts as an intermediary that dissolves the solder contacts, allowing them to become liquid without high heating. The medium facilitates the transition of solder from solid to liquid state and enables controlled wetting of metallisations while preventing harmful dissolution effects.
2Ease of operation
If the solder contacts remain liquid for a long period to allow component placement, then the components can be positioned correctly, but the solder dewets or the melting point is displaced causing premature solidification
Solution Approach 1:
The liquid solder contacts in the medium automatically wet the bond metallisations when components are placed, eliminating the need for external heating or pressure application. The system self-adjusts to achieve proper bonding as components settle into position.
Solution Approach 2:
The invention changes the controlling parameter for solder liquidity from temperature to concentration in the liquid medium. The solder remains liquid through dissolution rather than melting, allowing extended component placement time without dewetting or premature solidification.
3Reliability
If solid metal coatings are used instead of liquid solder, then unintentional interactions during contact are prevented, but bonding requires melting which occurs only upon contact
Solution Approach 1:
The metal coatings are prepared in advance as solid layers on components and substrate. They remain solid during handling and placement, preventing unintentional bonding. The melting and liquid phase formation occurs automatically upon contact during the bonding process itself.
Solution Approach 2:
The invention utilizes phase transition of metal coatings from solid to liquid upon contact through melting. This controlled phase change ensures that bonding occurs only when components are in the correct position, providing precise bonding while maintaining simplicity in the overall 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 method prevents premature dewetting and solidification issues, ensuring a stable bond between the substrate and components by maintaining the solder in a liquid state until it solidifies, reducing unintentional interactions and ensuring secure bonding.
Implementation Method 1
As a result of convection in the liquid solder, the solder reacts very much more rapidly with metallisations situated thereunder
Implementation Method 2
a solid solder contact degrades only as a result of diffusion processes which take place significantly more slowly
Implementation Method 3
the at least one element is adjusted by the surface tension of the solder on the substrate itself
Data Source
AI summary
A method is provided for the production of a bond between a first element having at least one first metal coating and at least one further element having a second metal coating, the at least one further element being freely moveable in a medium and the at least one first metal coating of the first element and the second metal coating of the at least one further element being in a solid state, a liquid phase being formed upon contact of the at least one first metal coating with the second metal coating.