Type 4.5 UltraFine Powder Solder Paste

TS107E is a widely used no‑clean, leaded solder paste that is offered in several powder size options. This article specifically covers the Type 4.5 version, designated as Type 4.5 Ultra‑Fine Powder Solder Paste. As a leading Solder paste type 4.5 product, TS107E delivers outstanding performance in ultra‑fine pitch printing, head‑in‑pillow defect prevention, and in‑circuit probe test yield, making it ideal for high‑density electronic assembly applications that demand exceptional printing resolution and process stability.

Solder Paste Composition

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste consists of Sn63/Pb37 alloy powder and solder flux. According to the technical datasheet, this Solder paste type 4.5 uses the Sn63/Pb37 eutectic alloy (63% tin, 37% lead) with a melting point of 183°C. The flux content of this Type 4.5 Ultra‑Fine Powder Solder Paste is approximately 5% (by weight), utilising an ROL0‑grade activator system (the highest reliability level per IPC J‑STD‑004). This Solder paste type 4.5 formulation ensures minimal residue after reflow, full and reliable solder joints, and fully meets no‑clean process requirements.

Solder Paste Type – Customisable Powder Size Selection

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste is part of a broader product family that offers the industry’s widest range of Solder Paste Type options, including:

Among these, Type 4.5 is the core focus of this article. The Type 4.5 Ultra‑Fine Powder Solder Paste features a proprietary particle size distribution optimised for ultra‑fine pitch applications down to 200μm (8mil) apertures. This advantage distinguishes TS107E from other Solder paste type 4.5 products on the market.

Sn63/Pb37 Alloy Advantages

As a typical Type 4.5 Ultra‑Fine Powder Solder Paste, TS107E utilises the Sn63/Pb37 eutectic alloy, offering the following core benefits:

• Eutectic characteristics – melting point of 183°C, no plastic zone, rapid solidification during soldering, reducing cold solder risks;
• Mature technology – Sn63/Pb37 is the most widely applied alloy system among Solder paste type 4.5 and other leaded solder pastes;
• Superior wettability – excellent performance across various PCB surface finishes, especially on CuOSP;
• Cost‑effectiveness – compared to lead‑free alloys, Type 4.5 Ultra‑Fine Powder Solder Paste offers competitive material costs while enabling finer printing.

This Solder paste type 4.5 achieves complete alloy coalescence even on apertures as small as 200μm, producing uniform and full solder joints – a critical requirement for ultra‑fine pitch assemblies.

Flux and Electrical Reliability

The flux in TS107E employs an ROL0‑grade activator system (IPC J‑STD‑004 highest reliability level) and is halogen‑containing (confirmed by titration and silver halide tests). This flux system ensures that the Type 4.5 Ultra‑Fine Powder Solder Paste passes all of the following tests:

This flux system leaves colourless, transparent, dry, and reliably insulating residue after reflow, meeting no‑clean requirements while delivering IPC Class III voiding performance (the highest IPC 7095 classification).

Printing Performance and Process Parameters

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste demonstrates outstanding printing consistency and high process capability index (Cpk) on the printer, especially for fine‑pitch stencils. The key printing parameters for this Solder paste type 4.5 are:

• Printing speed: 25–150mm/s (1–6 in/s), supporting high‑speed printing for fast cycle times and high throughput;
• Squeegee pressure: 0.18–0.27kg/cm (1.0–1.5lbs/inch); higher speeds require increased pressure;
• Squeegee angle: 60° (standard);Squeegee material: metal or polyurethane rubber (hardness 80–90 Shore);
• Stencil thickness: 100–150μm (4–6mil);
• Stencil separation speed: 3–10mm/s;
• Stencil material: recommended Alpha series electroformed/laser‑cut stencils.

This Type 4.5 Ultra‑Fine Powder Solder Paste exhibits minimal viscosity variation during continuous printing at 25°C/50%RH, significantly reducing cleaning frequency and improving production line efficiency – particularly well‑suited for high‑throughput, fine‑pitch applications

Handling and Process Guidelines

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste must be stored refrigerated at 0–10°C (shelf life: 6 months). Prior to use, the Solder paste type 4.5 should be allowed to warm to room temperature for approximately 4 hours (ensure temperature ≥19°C before opening), and then mixed:

• Manual mixing: can be stirred with a spatula until uniform;
• Centrifugal mixer (solder paste mixer): recommended speed below 300 RPM, with a pause after every 30–60 seconds of mixing;
• Important: Never mix solder paste recovered from the stencil with unused paste in the same container, as this will alter the rheological properties of the unused Type 4.5 Ultra‑Fine Powder Solder Paste.

After printing, reflow should be completed as soon as possible. The reflow profile recommends a peak temperature of 210–220°C (above the 183°C melting point), and can be performed in air or nitrogen atmospheres.

Core Differentiating Advantages – Low Head‑in‑Pillow and High Probe Testability

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste offers two industry‑leading core advantages:

• Low head‑in‑pillow defect rate – This Solder paste type 4.5 delivers outstanding resistance to head‑in‑pillow defects in BGA/CSP soldering, effectively reducing open defects caused by PCB warpage and component coplanarity issues, improving first‑pass yield.
• Excellent probe testability – TS107E provides best‑in‑class in‑circuit probe test yield. After reflow, the solder joint surface has minimal, colourless, transparent flux residue, resulting in low probe contact resistance and significantly reducing ICT (in‑circuit test) misjudgements. This Type 4.5 Ultra‑Fine Powder Solder Paste is the preferred choice for leaded‑process ICT testing applications.
• Low voiding – Meets IPC 7095 Class III voiding performance (the highest level), ensuring long‑term reliability.

Application Scenarios and Supply Capacity

TS107E Type 4.5 Ultra‑Fine Powder Solder Paste has been deployed in volume production across the following sectors:

This Type 4.5 Ultra‑Fine Powder Solder Paste serves over 50 customers, with a monthly production capacity exceeding 3 tonnes and ample inventory, enabling delivery within 48 hours.