Diffusion Solder Preform with Preformed Intermetallic Zone
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Solution Overview
Problem
The existing methods for forming diffusion solder connections require high precision and significant manufacturing effort, leading to increased costs and thermal loads, and are limited by the thickness of the solder molding and the time required for phase growth of intermetallic phases.
Innovation Solution
A solder molding composed of a tin-based solder material and a metallic material, where the metallic material diffuses into the solder material during heating, forming an intermetallic phase with a higher melting point, allowing for a diffusion zone to form between joining partners with a controlled distance and heat treatment to reduce thermal loads and enable efficient assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pre-formed solder components are used to create diffusion solder joints, then the diffusion paths can be kept short resulting in mechanically stable connections, but high precision in production is required increasing manufacturing effort and costs
Solution Approach 1:
The soldering element is segmented into distinct functional zones: a first region with solder material for forming the diffusion zone, and a second region with receiving surfaces for joining partners. This segmentation allows the diffusion process to be confined to specific areas while maintaining ease of manufacture.
Solution Approach 2:
The patent introduces an intermediary structure - the soldering element with pre-configured solder material regions - that mediates between the joining partners. This intermediary provides the necessary diffusion paths without requiring high precision alignment, as the solder material is already positioned in the first region.
2Length of moving object
If very thin pre-formed solder components are used to shorten diffusion paths, then mechanically stable connections are achieved, but very flat and clean surfaces on joining partners are required increasing joining accuracy demands
Solution Approach 1:
The soldering element divides the solder material into a first region for diffusion and a second region for joining, allowing the diffusion path to be controlled within the first region without requiring the entire component to be extremely thin.
Solution Approach 2:
The first region containing solder material is specifically designed to have the necessary thickness for diffusion, while the second region with receiving surfaces can have different properties. This local quality differentiation allows optimized diffusion paths without imposing stringent requirements on the entire component or joining surfaces.
3Loss of time
If diffusion zones are formed extending to joining surfaces to complete diffusion solder joints quickly, then shorter processing times are achieved, but higher thermal loads are applied to joining partners
Solution Approach 1:
The soldering element segments the material distribution such that solder material is concentrated in the first region, allowing diffusion to occur efficiently in this localized area without requiring the entire joining interface to be heated to high temperatures for extended periods.
Solution Approach 2:
The diffusion process is facilitated by providing sufficient solder material in the first region, allowing the diffusion zone to develop adequately without requiring excessive heating time or temperature that would increase thermal loads on the joining partners.
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 allows for the formation of reliable diffusion solder connections with reduced thermal loads and processing times, enabling the completion of diffusion solder connections in a single soldering process alongside ordinary solder connections, with the potential for faster assembly and lower energy input.
Implementation Method 1
the metallic material diffuses into the solder material during heating, forming an intermetallic phase
Implementation Method 2
forming an intermetallic phase with a higher melting point
Data Source
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AI summary
The invention relates to a solder preform for establishing a diffusion solder connection. The solder preform (11) has a solder material (20), which also forms the joining surfaces (12, 13) of the solder preform (11). The invention provides for the solder preform to have a further phase (18) for example in the form of particles, of which the material diffuses into the solder material (20) and thus forms a diffusion zone (19). The invention provides for this diffusion operation to be initiated in the solder preform during production of the latter (for example 1 by way of a heat treatment), as a result of which a diffusion solder connection forms more quickly when the solder preform (11) is subsequently soldered. Moreover, the diffusion zone (19), which may be formed by an intermetallic compound, stabilizes the solder preform while the solder material (20) is being liquefied. The invention nevertheless provides for the solder material still to be available at the joining surfaces (12, 13), in order for the solder connection to adjacent joining partners to be formed. The invention also relates to a method for producing such a solder preform.