Halogen-Free Solder Paste

Halogen-Free Solder Paste – TENSAN TS-503 Low-Silver Solution

In today's environmentally conscious electronics manufacturing landscape, the demand for solder paste lead free and halogen‑free materials has never been higher. Global regulations such as RoHS and REACH, combined with customer specifications for green products, drive manufacturers to seek solder paste lead free formulations that not only eliminate lead but also minimise halogens – chlorine, bromine, and other elements that can contribute to corrosion and ionic contamination. TENSAN TS‑503 is a Halogen-Free Solder Paste engineered to meet these stringent requirements while delivering excellent soldering performance. With its unique Sn‑Ag0.3‑Bi35 alloy, Type‑4 powder, and low‑halogen flux system (<1500 ppm), this solder paste lead free product offers the ideal balance of environmental compliance, thermal protection, and process reliability – making it the preferred Halogen-Free Solder Paste for LED lighting, consumer electronics, and heat‑sensitive assemblies.

What Is TENSAN TS-503 Halogen-Free Solder Paste?

TENSAN TS‑503 is a Halogen-Free Solder Paste designed for SMT assembly processes that demand environmental compliance and medium‑temperature reflow. This advanced solder paste lead free formulation is composed of:

• Lead‑free alloy – Sn‑Ag0.3‑Bi35, with lead impurities strictly controlled below 0.04%
• Low‑halogen flux – Halogen content below 1500 ppm, meeting strict industry standards
• Lower reflow temperature – Bismuth content (34.5–35.5%) reduces melting point, protecting heat‑sensitive components
• Excellent printability – Type 4 powder (20–38 μm) ensures consistent deposit volume for fine‑pitch applications
• No‑clean convenience – Minimal, clear residue that supports ICT testing without cleaning
• High reliability – Passes SIR and electromigration tests for long‑term electrical stability

As a Halogen-Free Solder Paste, TS‑503 is trusted by manufacturers who must comply with environmental regulations without compromising soldering quality or production efficiency.

Key Specifications

Alloy Composition & Physical Properties

Chemical & Electrical Properties

Physical Properties

Why Choose TENSAN TS-503 as Your Halogen-Free Solder Paste?

1. Low‑Halogen Content – Meets Strict Environmental Standards

TS‑503 is formulated with a flux system containing less than 1500 ppm halogens, comfortably meeting the "halogen‑free" definitions used by many OEMs and industry standards (typically < 1500 ppm total halogens). This Halogen-Free Solder Paste reduces the risk of ionic contamination and corrosion, making it ideal for applications where long‑term reliability is critical. As a solder paste lead free product, TS‑503 also eliminates lead entirely, ensuring full RoHS compliance.

2. Lead‑Free Compliance – A True Solder Paste Lead Free Product

TS‑503 is 100% lead‑free, with lead impurities strictly controlled below 0.04%. This solder paste lead free formulation meets the requirements of EU RoHS, REACH, and other global environmental regulations. By choosing TS‑503, manufacturers can confidently export their products to all major markets without concern for non‑compliance penalties. This Halogen-Free Solder Paste is the responsible choice for environmentally conscious manufacturing.

3. Lower Reflow Temperature – Protects Heat‑Sensitive Components

The Sn‑Ag0.3‑Bi35 alloy in TS‑503 reduces the peak reflow temperature to 210–230°C – significantly lower than SAC305. This protects heat‑sensitive components such as LEDs, plastic connectors, and flexible substrates from thermal degradation. The low‑halogen flux system ensures that even at these lower temperatures, the solder paste provides excellent wetting and strong joint formation.

4. Cost‑Effective Formulation – Low Silver Content

With silver content reduced to 0.3–0.5%, TS‑503 offers significant material cost savings compared to higher‑silver pastes. This makes it an attractive solder paste lead free choice for high‑volume production, where cost efficiency is as important as environmental compliance. The Halogen-Free Solder Paste formulation balances performance with affordability.

5. Excellent Printability – Consistent Fine‑Pitch Performance

With Type 4 powder (20–38 μm), TS‑503 delivers:

• Consistent paste volume transfer for fine‑pitch applications down to 0.25 mm
• Sharp edge definition and minimal slump after printing
• Compatibility with both standard and fine‑pitch stencil designs

Whether you use an automatic printer or manual equipment, this Halogen-Free Solder Paste adapts to your process requirements, ensuring high first‑pass yields.

6. No‑Clean, Low‑Residue – Saves Process Steps

The low‑halogen flux system leaves a clear, non‑conductive residue that:

• Supports ICT (In‑Circuit Test) without post‑reflow cleaning
• Eliminates cleaning process steps, reducing chemical costs and cycle time
• Maintains high surface insulation resistance even under humid conditions (SIR > 1.7 × 10⁹ Ω)

This no‑clean design makes TS‑503 a highly efficient solder paste lead free product for high‑volume production.

7. High Electrical Reliability – Essential for Long‑Term Performance

With SIR exceeding 1.7×10⁹ Ω (IPC) and 6.4×10¹² Ω (Bellcore), and passing 500‑hour electromigration testing, TS‑503 ensures that the residue left by this Halogen-Free Solder Paste does not compromise long‑term reliability – even in humid environments. This makes it a trusted solder paste lead free product for automotive, telecommunications, and industrial applications.

Recommended Application Parameters

Stencil Design Guidelines

Stencil Technologies: Electroformed and laser‑cut stencils with electro‑polishing provide optimal printing characteristics. "Roof‑shaped" aperture designs help reduce solder balling between components.

Printing Conditions

Reflow Profile (Recommended)

The lower peak temperature of this Halogen-Free Solder Paste provides a protective thermal environment for heat‑sensitive components while still delivering strong, reliable solder joints. Adjust profiles based on your specific reflow oven and PCB assembly requirements.

Storage and Handling Guidelines

Important: Do not mix leftover solder paste with fresh paste in the same container. Always warm up this Halogen-Free Solder Paste in its sealed container to prevent moisture condensation, which can cause spattering during reflow.

Alloy Composition Overview 

Typical Applications for This Halogen-Free Solder Paste

TS‑503 is ideal for applications requiring environmental compliance and medium‑temperature reflow:

• LED Lighting – Protects LED chips and phosphor layers from thermal degradation
• Consumer Electronics – Smartphones, tablets, wearables with heat‑sensitive components
• Automotive Electronics – Sensors, lighting modules, ECUs requiring low‑halogen materials
• Flexible PCBs – Prevents warpage and delamination of flexible substrates
• Step‑Soldering Processes – Secondary reflow after high‑temperature SAC assembly
• Telecommunications – RF modules, base station components

Green Products – Any application requiring solder paste lead free and low‑halogen complianceAs a versatile Halogen-Free Solder Paste, TS‑503 is trusted by manufacturers across these diverse industries.

Quality Assurance

Every batch of TENSAN TS‑503 is accompanied by a Certificate of Analysis confirming:

• Model and batch number
• Alloy composition (Sn‑Ag0.3‑Bi35) – verified solder paste lead free
• Powder size distribution (Type 4, 20–38 μm)
• Flux content (wt%)
• Halogen content (< 1500 ppm)

Viscosity at 25°COur manufacturing processes ensure consistent solder paste quality from lot to lot, giving you confidence in every production run with this Halogen-Free Solder Paste.

Frequently Asked Questions

Q: What makes TS‑503 a halogen-free solder paste?

A: TS‑503 is formulated with a flux system containing less than 1500 ppm halogens, meeting industry definitions for Halogen-Free Solder Paste. This reduces ionic contamination risks while maintaining excellent soldering performance.

Q: Is TS‑503 a solder paste lead free product?

A: Yes. TS‑503 is 100% lead‑free, with lead impurities strictly controlled below 0.04%. It fully complies with RoHS and REACH requirements as a solder paste lead free product.

Q: How does TS‑503 compare to standard SAC305 solder paste?

A: TS‑503 has a lower silver content (0.3–0.5% vs 3.0%) and contains bismuth, which lowers the melting point. It is a Halogen-Free Solder Paste with lower halogens and provides significant material cost savings.

Q: Does TS‑503 require post‑reflow cleaning?

A: No. TS‑503 is a no‑clean solder paste lead free product. The residue is clear, non‑conductive, and compatible with ICT testing, eliminating cleaning steps and reducing costs.

Q: What is the shelf life of this Halogen-Free Solder Paste?

A: Six months from production date when stored at 5–10°C. At room temperature, it can be kept for up to 15 days.

Q: Can TS‑503 be used for nitrogen reflow?

A: Yes, it performs well in both air and nitrogen reflow environments.

Q: What industries commonly use this solder paste lead free product?

A: TS‑503 is widely used in LED lighting, consumer electronics, automotive, flexible PCB, and telecommunications manufacturing – anywhere that solder paste lead free and low‑halogen compliance are required.

Conclusion

For manufacturers who demand environmental compliance without compromising soldering performance, TENSAN TS‑503 is the definitive Halogen-Free Solder Paste solution. This solder paste lead free product offers excellent printability, stable viscosity, low‑halogen content, no‑clean convenience, and proven electrical reliability – all at a cost‑effective low‑silver composition.

By choosing TS‑503, you select a Halogen-Free Solder Paste that:

• Meets strict low‑halogen and solder paste lead free requirements
• Protects heat‑sensitive components with lower reflow temperatures (210–230°C peak)
• Delivers consistent, fine‑pitch print performance with Type‑4 powder
• Eliminates cleaning steps with no‑clean residue
• Ensures long‑term reliability with high SIR and electromigration resistance

Reduces material costs with low silver content (0.3–0.5%)Upgrade to TENSAN TS‑503 – the Halogen-Free Solder Paste that combines compliance, performance, and cost efficiency.

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