Lead-Free No-Clean SnAgCu Solder Paste for High-Reliability SMT Assembly

In the rapidly evolving landscape of electronics manufacturing, the selection of an appropriate solder paste type has become increasingly critical for achieving consistent production quality and long-term product reliability. As component geometries continue to shrink and PCB designs grow more complex, the solder paste type chosen for your assembly line directly influences everything from printing yield to field performance. Among the various solder paste type options available, SnAgCu-based formulations have emerged as the industry standard for lead-free assembly, offering an optimal balance of melting characteristics, mechanical strength, and cost-effectiveness.

TS505 represents a premium solder paste type engineered specifically for high-reliability SMT applications. This no-clean, lead-free formulation is based on the Sn99Ag0.3Cu0.7 (SAC0307) alloy system and has been developed to address the critical challenges faced by modern electronics manufacturers: fine-pitch printing capability, excellent wetting performance, low voiding, and minimal residue. Whether you are producing telecommunications infrastructure, automotive electronics, or consumer devices, TS505 delivers the process stability and joint integrity that today's demanding applications require.

Product Specifications

Solder Paste Specifications

Core Advantages of This Solder Paste Type

1. Wide Reflow Process Window

This solder paste type supports reflow soldering in both air and nitrogen atmospheres and is compatible with various reflow oven types (infrared/hot air). The generous process window allows TS505 to adapt to PCBs of varying densities and thicknesses, effectively reducing defects such as solder beads, bridging, and tombstoning.

2. Excellent Wettability and Solder Wicking

Thanks to its optimally activated flux system, TS505 demonstrates superior wetting and solder wicking performance during the reflow stage. This solder paste type forms full, bright solder joints even on OSP-coated or mildly oxidized pads. The strong capillary action ensures consistent fillet formation, resulting in reliable mechanical and electrical connections.

3. Low Voiding

The refined flux formulation of this solder paste type effectively minimizes void formation during reflow – particularly critical for large thermal-mass components such as QFN, LGA, and thermal pads. Low voiding significantly enhances solder joint reliability by improving thermal conductivity and reducing mechanical stress points.

4. Outstanding Printability and Stencil Life

TS505 offers excellent rollability and thixotropic properties, making it fully compatible with solder paste printers. Whether using stainless steel or rubber squeegees, this solder paste type delivers stable, uniform paste release.

• Stable viscosity – Minimal shear degradation during extended printing, reducing the need for frequent parameter adjustments.
• Excellent shape retention – Printed deposits hold their geometry without slump, even on fine-pitch pads.
• Extended stencil life – The paste resists drying in apertures, reducing cleaning frequency and improving production line efficiency.

5. Minimal Residue and High Insulation Resistance

After reflow, this solder paste type leaves a dry, translucent residue that is non-conductive and probe-friendly. The residue characteristics include:

• Residue Dryness – Passed (JIS Z 3284)
• Surface Insulation Resistance (SIR) – ≥ 1.0 × 10⁸ Ω at 40°C / 90% RH; ≥ 5.0 × 10⁸ Ω at 80°C / 85% RH
• Water Extraction Resistance – ≥ 1.0 × 10⁵ Ω·cm
• Copper Corrosion Test – Passed
• Halogen Content – 0.085% (L1 level, meeting low-halogen requirements)

The low-residue characteristic gives this solder paste type a clear advantage in no-clean processes, effectively mitigating risks of leakage current and electromigration. The dry, clear residues are easily probe-tested, making them suitable for ICT (In-Circuit Test) without any cleaning step.

Process Guidelines

Storage & Thawing

Important: Always warm sealed containers to ambient temperature before opening to prevent moisture condensation, which can cause spattering and increased voiding – a concern for any solder paste type.

Solder Paste Mixing

After thawing, it is recommended to use a solder paste mixer or perform manual stirring for 1–2 minutes to ensure complete homogenization of powder and flux. This step restores the paste to its optimal rheology, ensuring consistent print performance.

Stencil Thickness Guidelines

Typical Applications

This solder paste type is designed for high-reliability assemblies where consistent printing and joint quality are paramount:

• Telecom Base Stations & Server Motherboards – Large-format PCBs with stringent voiding requirements
• Automotive Electronics (ECU, BMS) – Requiring high reliability and thermal cycling resistance
• Industrial Controls & Power Modules – Critical for joint strength and insulation resistance
• Consumer Electronics (TWS earbuds, smart wearables) – Fine-pitch components requiring precise printing

Quality Assurance

Each batch of TS505 is accompanied by a Certificate of Analysis covering:

• Solder paste model and batch number
• Alloy composition verification
• Flux content (wt%)
• Viscosity measurement (at 25°C)

Our quality system ensures consistent product performance from lot to lot, giving you confidence in your production process.

Packaging

Frequently Asked Questions

Q: Is TS505 suitable for both standard and fine-pitch printing?

A: Yes. This solder paste type is formulated to perform equally well on standard 0.5 mm pitch and ultra-fine 0.25 mm (10 mil) pitch applications.

Q: What stencil is recommended for this solder paste type?

A: Laser-cut stainless steel stencils with electro-polished apertures are recommended for optimal release and shape retention with this solder paste type.

Q: Does TS505 support paste-in-hole (PiH) applications?

A: Yes, this solder paste type is suitable for paste-in-hole processes.

Q: How long can TS505 sit on the stencil during production?

A: Under standard shop-floor conditions (20–25°C, RH <65%), TS505 maintains print performance throughout typical production shifts. Always reseal unused paste to maximize its usable life.

Q: What is the recommended storage temperature for this solder paste type?

A: This solder paste type should be stored at 2–10°C in a refrigerated environment. Do not freeze.

Conclusion

Selecting the right solder paste type is one of the most critical decisions in SMT assembly. TS505 delivers everything you need: consistent printing, superior wetting, minimal residue, and proven reliability across a wide range of applications. This solder paste type helps you achieve:

• Higher first-pass yieldsLower rework rates
• Reduced production downtime
• Consistent solder joint quality

For manufacturers seeking a stable, high-quality lead-free solder paste type that bridges the gap between tin-lead legacy processes and today's demanding lead-free requirements, TS505 is the proven choice.Product NameLead-Free No-Clean SnAgCu Solder Paste for High-Reliability SMT Assembly

Contact Information

TENSAN VIETNAM CO., LTD

TS10 Road, Tien Son Industrial Park, Bac Ninh Province, Vietnam

Tel: +84-222-650-8818

Email: mark@sztensan.com