Lead-Free High-Temperature Solder Paste

Product Details

I. Solder Paste Composition

The Solder Paste Composition of TS-350-1 consists of Sn96.5Ag3Cu0.5 alloy powder and Solder Flux. According to the technical datasheet, the Solder Paste Composition contains 96.5% Tin, 3.0% Silver, and 0.5% Copper, belonging to the SnAgCu Solder Paste alloy family with a melting point of 221–227°C. The Solder Flux content within this Solder Paste Composition is 10.5±0.5wt%, presenting a light gray, smooth paste appearance with no separation, and a metal content of approximately 89.5%. This Solder Paste Composition design ensures the SnAgCu Solder Paste leaves minimal residue after high-temperature reflow with full and reliable solder joints.

II. Solder Paste Type and Printing Performance

TS-350-1 adopts Solder Paste Type 4 solder powder with a particle size of 20–38μm, suitable for fine-pitch and high-density printing applications. On the Solder Paste Printer, this SnAgCu Solder Paste operates with the following printing parameters: squeegee angle 60° (standard, adjustable to 45° for fine-pitch applications), printing pressure approximately 200g/cm², and recommended stencil materials including stainless steel, brass, or nickel-plated stencils. TS-350-1 delivers excellent printing performance and extended stencil life on the Solder Paste Printer, with minimal viscosity variation during continuous printing and stencil life exceeding 8 hours. This Solder Paste Type 4 powder size, when paired with the Solder Paste Printer, achieves stable and uniform paste release, significantly reducing cleaning frequency and improving production line efficiency.

III. Solder Paste Lead Free and SAC305 Alloy Advantages

TS-350-1 is a typical Solder Paste Lead Free product, fully compliant with RoHS environmental directives. The Sn96.5Ag3Cu0.5 (SAC305) alloy used in this Solder Paste Lead Free product is one of the most mature and widely applied formulations within the SnAgCu Solder Paste family, commonly referred to in the industry as Solder Paste 305. As a Solder Paste Lead Free product, TS-350-1's Solder Paste 305 alloy offers the following advantages:

• Optimal melting point: 221–227°C, compatible with standard high-temperature reflow processes
• High solder joint strength: 3.0% silver content provides excellent fatigue resistance
• Superior wettability: Forms full, bright solder joints even on OSP-coated or mildly oxidized pads

Compared to other Solder Paste Lead Free alloys, this SnAgCu Solder Paste achieves an excellent balance between cost and reliability, establishing itself as the industry standard in the Solder Paste 305 category.

IV. Solder Flux and Electrical Reliability

The Solder Flux in TS-350-1 employs a low-ionic activator system with halogen content of only 0.085% (L0 grade, <0.5%). This Solder Flux ensures the SnAgCu Solder Paste passes all of the following tests:

This Solder Flux system ensures TS-350-1 leaves minimal residue with reliable insulation after reflow, satisfying no-clean process requirements and effectively preventing leakage risks even under high-temperature and high-humidity conditions.

V. Solder Paste Mixer and Process Guidelines

TS-350-1 must be stored refrigerated at 2–10°C (do not freeze) with a shelf life of 6 months. Prior to use, the Solder Paste must be allowed to sit at room temperature for at least 4 hours for thawing, followed by mixing via a Solder Paste Mixer or manual stirring. The Solder Paste Mixer is recommended to operate for 1–2 minutes to ensure uniform Solder Paste Composition with viscosity restored to 220,000±30,000 mPa·s (Malcom Viscometer @25°C, 27.9RPM, Rotor R6). After printing this SnAgCu Solder Paste on the Solder Paste Printer, PCBs should be reflowed as soon as possible. The reflow profile recommends a peak temperature of 240–250°C, with time above 230°C maintained at 20–40 seconds, time above 221°C at 60–90 seconds, preheat ramp rate ≤2.5°C/s, and cooling rate ≥4°C/s (rapid cooling promotes fine grain structure formation).

• Reflow Profile
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VI. Wide Reflow Process Window and Low Voiding

TS-350-1 offers a wide reflow process window and can be reflowed in air or nitrogen atmospheres, accommodating PCBs of varying densities and geometries as well as different reflow oven types. The low voiding characteristic of this SnAgCu Solder Paste is particularly critical for large thermal-mass components (such as QFN, LGA, and thermal pads) . Combined with excellent wettability and solder wicking capability, this product significantly reduces defects including solder beads and bridging, enhancing overall solder joint reliability.

VII. Application Scenarios and Supply Capacity

This SnAgCu Solder Paste has been deployed in volume production across four major sectors: Telecom Base Stations and Server Motherboards (large-format PCBs with stringent voiding requirements), Automotive Electronics (ECU, BMS) (requiring high reliability and thermal cycling resistance), Industrial Controls and Power Modules (critical for joint strength and insulation resistance), and Consumer Electronics (TWS earbuds, smart wearables) (fine-pitch components). TS-350-1 maintains a monthly production capacity exceeding 3 tons with ample inventory, ensuring stable supply and fully supporting continuous SMT line production requirements.