Solder Composition Void Reduction via Solvent Blend
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Solution Overview
Problem
Existing solder compositions struggle to prevent the generation of large-diameter voids when printed over large areas on electronic components with wide electrode terminals, despite the use of highly viscous solvents with high boiling points, which are not effective in reducing voids.
Innovation Solution
A solder composition incorporating a solvent blend of isobornyl cyclohexanol and a solvent with low viscosity and a specific boiling point range, along with a thixotropic agent, to enhance fluidity and gas release, thereby reducing void formation and maintaining printability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a highly viscous solvent with a high boiling point (e.g., isobornyl cyclohexanol) is used in a solder composition, then the solder composition can restrain the generation of small voids, but it is not effective for reducing large-diameter voids when applied to electronic components with large area electrode terminals
Solution Approach 1:
The patent changes the physical parameters of the solvent by using a blend of two solvents with different viscosities and boiling points. The first solvent has high viscosity and high boiling point, while the second solvent has low viscosity and intermediate boiling point. This parameter variation allows the solder composition to achieve both small void restraint and large-diameter void reduction when applied to large area electrode terminals.
Solution Approach 2:
The patent creates a composite solvent system by combining two different solvents in specific proportions. This composite approach allows the solder composition to exhibit both the void-restraining properties of high viscosity solvents and the large-diameter void reduction capability of low viscosity solvents, achieving synergistic effects that neither solvent could provide alone.
2Reliability
If a highly viscous solvent is used to prevent void formation, then small voids are restrained, but the solder composition fluidity is insufficient for large print areas, preventing gas release and causing large-diameter voids
Solution Approach 1:
The patent adjusts the viscosity parameter of the solvent system by introducing a low viscosity solvent with intermediate boiling point. This creates a balanced fluidity that allows gas to escape during the printing and heating processes while maintaining enough viscosity to restrain small void formation, resolving the contradiction between void prevention and gas release.
3Area of stationary object
If the solder composition is printed over a large print area, then it can accommodate large-sized electronic components, but large-diameter voids are likely to be generated
Solution Approach 1:
The patent modifies the solvent viscosity and boiling point parameters to enable the solder composition to be printed over large areas while preventing void formation. The low viscosity solvent enhances fluidity for large area coverage and gas release, while the high boiling point ensures solvent evaporation occurs after solder melting, preventing voids even in large print areas.
4Reliability
If a solvent with high boiling point is used, then solvent evaporation is prevented before solder melting, but the solder composition lacks fluidity for proper gas release
Solution Approach 1:
The patent optimizes the boiling point and viscosity parameters by using a solvent blend. The low viscosity solvent provides necessary fluidity for gas release, while its intermediate boiling point ensures it remains liquid during the critical phase of solder melting and void prevention, achieving the right balance between fluidity and void prevention.
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
The solder composition effectively restricts the generation of large-diameter voids and ensures sufficient printability even over large areas, as demonstrated by improved void ratios and printability in tests, with the solvent blend facilitating gas release and preventing shear drop during heating.
Implementation Method 1
the component (C1) has a high boiling point, the component (C1) hardly volatilizes before the solder melts
Implementation Method 2
a component (C2) in a form of a solvent whose viscosity at 20 degrees C. is 10 mPa·s or less
Implementation Method 3
a component (D) in a form of a thixotropic agent
Implementation Method 4
before the solder melts
Data Source
AI summary
A solder composition of the invention includes: a flux composition containing a component (A) in a form of a rosin-based resin, a component (B) in a form of an activator, a component (C) in a form of a solvent and a component (D) in a form of a thixotropic agent; and a component (E) in a form of a solder powder. The component (C) in a form of the solvent contains a component (C1) in a form of a isobornyl cyclohexanol and a component (C2) in a form of a solvent whose viscosity at 20 degrees C. is 10 mPa·s or less and whose boiling point ranges from 220 degrees C. to 245 degrees C.