Sintering Preform via Desolvation and Compaction
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Solution Overview
Problem
Current methods for sintering electronic components using solder pastes and suspensions face challenges such as high viscosity, clogging, irregular application, and poor adhesion due to desolvation difficulties, which lengthen the sintering process and compromise the integrity of the metal particles.
Innovation Solution
A method involving desolvation and compaction of brazing compositions containing micrometric or nanometric metal particles to produce preforms with controlled shape, thickness, and density, utilizing filtration, vacuum desolvation, and compacting techniques to create a stable preform for sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If solder paste or suspension is used for sintering, then metal particles can be dispersed and applied, but high viscosity causes difficult application and clogging
Solution Approach 1:
The patent applies preliminary action by performing desolvation and compaction of metal particles before the sintering process. The metal particles are pre-treated to remove solvents and binders, then compacted into a porous preform structure. This preliminary preparation eliminates the viscosity issues of traditional pastes, allowing easy application of the dry preform while maintaining good adhesion during sintering.
2Productivity
If desolvation is carried out on the substrate before sintering, then metal particles can be prepared, but the process time is lengthened
Solution Approach 1:
The patent performs desolvation as a preliminary action before applying the composition to the substrate. The metal particles are desolvated and compacted into a preform in advance, then the preform is applied to the substrate and sintered. This reordering eliminates the need for desolvation on the substrate, reducing total process time while ensuring complete solvent removal.
3Strength
If desolvation is carried out upstream of sintering, then metal particles are agglomerated, but adhesion to substrate is not optimal
Solution Approach 1:
The patent applies local quality by creating a porous preform structure with specific local characteristics. The preform has controlled porosity and density that allow it to maintain particle distribution stability during handling while providing good adhesion to the substrate during sintering. The local porous structure enables both particle stability and substrate adhesion simultaneously.
4Productivity
If transport of metal powder is performed, then preforms can be prepared in advance, but oxidation risks and loss of coherence increase
Solution Approach 1:
The patent uses an inert atmosphere (nitrogen or argon) during the transport and handling of metal particles and preforms. The inert gas environment prevents oxidation of the metal particles during transport and storage, maintaining particle coherence and reliability. This allows advance preparation of preforms without compromising particle integrity.
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 reduces sintering cycle times, ensures uniform adhesion, and enhances mechanical strength, allowing precise control over the sintering process and reducing oxidation risks, resulting in improved parallelism and consistency of electronic components.
Implementation Method 1
a step of desolvating the brazing composition
Implementation Method 2
the suspension of metal grains or of metal oxalate is subjected to a preliminary filtration step through a filtration membrane placed on a suction device
Implementation Method 3
a step of compacting the desolvated brazing composition so as to obtain a preform of metal particles or of metal oxalate
Implementation Method 4
the preform being suitable to be used for the sintering of an electronic, photonic, thermal or mechanical component on a substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a pretreatment method for a soldering composition comprising metallic particles with a particle size on the order of micrometers or nanometers, one or more binders, and one or more solvents. The method comprises: - a desolvation step of the soldering composition (8) to obtain a desolvated soldering composition (11); - followed by a compaction step of the desolvated soldering composition (11) to obtain a preform (3) of metallic particles. This preform is suitable for use in sintering an electronic, photonic, thermal, or mechanical component onto a substrate. The soldering composition (11) is represented either by a solder paste or by a suspension of metallic grains or metallic oxalate in a solvent. The invention also relates to a device for carrying out the method.