Advanced Solder Paste Formulation
Our innovative tin-bismuth solder paste represents a significant advancement in solder paste printing technology. This specialized formulation addresses critical challenges in electronic packaging, offering superior performance compared to conventional alternatives.
Developed for modern surface mount technology (SMT) applications, this solder paste delivers exceptional results in precision solder paste printing processes. Its unique composition ensures reliable performance across various electronic manufacturing scenarios, particularly where thermal sensitivity is a concern.
The formulation eliminates black ring phenomena, forms a uniform, transparent film on solder joints, and minimizes corrosion issues—all while maintaining excellent electrical insulation properties essential for high-quality electronic assemblies.
Technical Composition
Ingredient Composition
The tin-bismuth solder paste consists of the following components in precise quality percentages:
- Activator10% ~ 15%
- Solvent30% ~ 45%
- Film-forming agent30% ~ 40%
- Thixotropic agent7% ~ 15%
- Humectant1% ~ 10%
- Antioxidant3% ~ 4%
- Corrosion inhibitor2% ~ 3%
Key Advantages
- Eliminates black ring phenomenon in solder paste printing applications
- Forms uniform, transparent film on solder joints
- Creates crack-free solder connections
- Minimal corrosion to pads and solder joints
- Enhances electrical insulation properties
Composition Ratio Visualization
Component Details
Activator (10% ~ 15%)
The activator component plays a crucial role in the solder paste printing process by removing oxides from metal surfaces, ensuring proper wetting and adhesion. Our formulation uses carefully selected activators that balance reactivity with corrosion resistance.
The activator can be any one or a mixture of:
- o-iodobenzoic acid
- salicylic acid
- methylsuccinic acid
- sulfosalicylic acid
- adipic acid
Solvent (30% ~ 45%)
Solvents are essential for achieving the proper viscosity in solder paste printing applications, ensuring the paste flows correctly through stencils while maintaining shape after application. Our solvent system is designed for optimal performance across various temperature and humidity conditions.
The solvent can be any one or a mixture of:
- propylene glycol methyl ether
- ethylene glycol
- tetrahydrofurfuryl alcohol
Film-Forming Agent (30% ~ 40%)
The film-forming agent is critical for creating the protective layer that remains after solder paste printing and reflow. This component ensures the formation of a uniform, transparent film that covers the solder joint without flowing onto adjacent pads.
Our formulation uses rosin as the primary film-forming agent, selected for its excellent properties in creating protective barriers that enhance insulation and corrosion resistance while maintaining visual clarity.
This component is particularly important in solder paste printing applications where post-solder insulation and corrosion resistance are critical performance factors.
Thixotropic Agent (7% ~ 15%)
Thixotropic agents provide the essential viscosity characteristics required for successful solder paste printing. They ensure the paste flows under shear during application but maintains its shape afterward, preventing slumping and ensuring precise deposition.
Our formulation uses either:
- stearic acid amide
- modified castor oil derivatives
This component's concentration is carefully controlled to achieve optimal performance in various solder paste printing equipment and processes, from fine-pitch applications to larger component bonding.
Humectant (1% ~ 10%)
Humectants maintain the proper moisture balance in the solder paste, preventing premature drying during storage and ensuring consistent performance during solder paste printing operations.
Our formulation uses either:
- glycerol
- GE-511
Antioxidant (3% ~ 4%)
Antioxidants prevent oxidation of the metal components in the paste, maintaining shelf life and ensuring reliable performance during solder paste printing and reflow processes.
Our formulation uses tert-butylhydroquinone, selected for its stability and effectiveness in preventing oxidation at both room temperature and reflow temperatures.
Corrosion Inhibitor (2% ~ 3%)
Corrosion inhibitors play a vital role in protecting both the solder joints and the surrounding pads from degradation. This is particularly important in solder paste printing applications where residual materials might otherwise cause long-term reliability issues.
Our formulation uses 2-mercaptobenzothiazole, which forms a protective layer on metal surfaces. This inhibitor enhances the overall corrosion resistance of the solder joint assembly, extending the service life of electronic devices even in harsh environments.
The precise concentration of this component ensures effective corrosion protection without compromising the solder paste's performance in printing or reflow processes.
Preparation Method
Our tin-bismuth solder paste is manufactured using a precise, multi-step process designed to ensure consistent quality and performance in solder paste printing applications. Each step is carefully controlled to achieve the optimal formulation properties.
Ingredient Weighing
Accurately weigh each component according to the specified mass percentages: activator (10% ~ 15%), solvent (30% ~ 45%), film-forming agent (30% ~ 40%), thixotropic agent (7% ~ 15%), humectant (1% ~ 10%), antioxidant (3% ~ 4%), and corrosion inhibitor (2% ~ 3%). Ensure the total mass percentage sums to 100%.
Precise weighing is critical for maintaining the formulation's integrity and ensuring consistent performance in solder paste printing applications.
Initial Mixing
Add the weighed solvent and activator into a reaction kettle. Place the reaction kettle in a magnetic stirrer, set the appropriate temperature and rotation speed, and stir until the activator is completely dissolved.
Process Parameters:
- • Magnetic stirrer speed: 500 ~ 700 r/min
- • Stirring time: 5 ~ 10 minutes
- • Stirring temperature: 130 ~ 140°C
Film-Forming Agent Integration
Remove the reaction kettle from the magnetic stirrer and add the weighed film-forming agent and antioxidant. Return the reaction kettle to the magnetic stirrer, adjust the temperature and rotation speed, and continue stirring according to the specified parameters.
Process Parameters:
- • Initial reaction temperature: 110 ~ 125°C
- • Initial magnetic stirrer speed: 200 ~ 300 r/min
- • Initial stirring duration: 2 ~ 5 minutes
- • Increased speed: 500 ~ 700 r/min
- • Secondary stirring duration: 5 ~ 15 minutes (same temperature)
Final Formulation
Remove the reaction kettle again and add the weighed thixotropic agent, additional antioxidant, and corrosion inhibitor. Return the reaction kettle to the magnetic stirrer, reduce the reaction temperature, and stir until a paste-like consistency is achieved, resulting in the high-performance solder paste.
Process Parameters:
- • Reaction temperature: 90 ~ 110°C
- • Stirring speed: 500 ~ 700 r/min
- • Reaction duration: 10 ~ 15 minutes
- • Final step: Cool to room temperature
Throughout the reaction process, the reaction kettle is wrapped with plastic wrap to prevent contamination and maintain consistent conditions—an important detail for ensuring the paste's performance in critical solder paste printing applications.
Technical Background
Solder paste is a critical material in modern electronic packaging technology, enabling the precise placement and bonding of components in surface mount technology (SMT). In solder paste printing processes, the material must maintain appropriate viscosity at room temperature to hold components in place, then perform reliably during reflow soldering.
During reflow, the active components in the solder paste remove oxides from solder surfaces, reduce surface tension to facilitate proper wetting, while solvents and other components evaporate. Upon cooling, a metallurgical bond forms between the metal alloy and substrate, creating the electrical and mechanical connection between components and printed circuit boards.
Surface mount technology has become essential in electronic packaging due to its ability to accommodate the high integration and miniaturization requirements of modern electronic products. It offers advantages such as simplified工艺流程, excellent bonding performance, and broad applicability across various electronic manufacturing sectors.
Challenges in Traditional Formulations
While solder paste technology has advanced significantly, conventional formulations—particularly tin-bismuth based products—face several critical challenges that impact their performance in solder paste printing applications:
- Black ring formation around solder joints after reflow, which affects electrical insulation,焊接性能, corrosion resistance, and aesthetics
- Post-solder residue flowing onto pads, causing poor electrical insulation and corrosion
- Presence of metallic bismuth in black ring formations, which degrades alloy焊接性能 and electrical insulation
- Inadequate film formation by post-solder residues, failing to properly protect solder joints
- Corrosion of substrates and solder joints, particularly under thermal cycling conditions, leading to reduced product lifespan
Traditional approaches to addressing these issues, such as using inorganic acids or complex thixotropic agent blends, have achieved only limited success. These methods often fail to completely eliminate black rings, result in dull solder joint surfaces, and introduce formulation complexities that hinder industrial production.
Our innovative tin-bismuth solder paste formulation represents a breakthrough in addressing these challenges. By carefully selecting and balancing the components, we've developed a solution that excels in modern solder paste printing applications while overcoming the limitations of conventional products.
Applications & Performance Benefits
Electronics Manufacturing
Ideal for various electronic assembly processes, particularly where precision solder paste printing is required for miniaturized components.
- Printed circuit board assembly
- Consumer electronics production
- Automotive electronics
- Industrial control systems
Specialized Applications
Excels in applications where low-temperature processing is required, making it perfect for heat-sensitive components:
- LED lighting assemblies
- Solar photovoltaic systems
- Thermal-sensitive electronic components
- Medical device electronics
Performance Advantages in Solder Paste Printing
Eliminates Black Ring Phenomenon
Our formulation completely eliminates the unsightly and problematic black ring that forms around solder joints in conventional tin-bismuth pastes. This not only improves aesthetics but also enhances overall joint performance in solder paste printing applications.
Superior Protective Film Formation
The paste forms a uniform, transparent protective film over solder joints after reflow. This film remains precisely on the joint without flowing onto adjacent pads, maintaining excellent insulation properties critical for reliable electronic performance.
Crack-Free Solder Joints
The unique formulation ensures the formation of crack-free solder joints, even under thermal cycling conditions. This significantly enhances the mechanical reliability and longevity of electronic assemblies produced using our solder paste printing solutions.
Enhanced Electrical Insulation
By preventing residue flow and forming an effective protective barrier, our solder paste significantly improves electrical insulation properties compared to conventional formulations. This is particularly important in high-density electronic assemblies where component spacing is minimal.
Excellent Corrosion Resistance
The carefully balanced formulation, including specialized corrosion inhibitors, minimizes corrosion of both solder joints and pads. This is especially valuable in harsh environments or applications where thermal cycling could otherwise lead to moisture absorption and subsequent corrosion.
Industrial Viability
Unlike complex alternative formulations that address some issues but are difficult to produce at scale, our solder paste is designed for industrial manufacturing. Its straightforward production process ensures consistent quality while delivering superior performance in solder paste printing applications.
Conclusion
Our tin-bismuth solder paste represents a significant advancement in solder paste technology, addressing critical limitations of conventional formulations while maintaining excellent performance in solder paste printing applications.
By carefully balancing the composition and optimizing the manufacturing process, we've developed a product that eliminates black ring formation, forms effective protective films, prevents corrosion, and enhances electrical insulation—all while remaining suitable for large-scale industrial production.
This innovative formulation is particularly well-suited for modern electronic manufacturing challenges, including the miniaturization of components, the need for reliable performance in harsh environments, and the requirements of heat-sensitive electronic assemblies. Its superior properties make it an ideal choice for advanced solder paste printing processes across various industries.