I. Definition and Core Features

Mini solder paste is a high-precision soldering material designed specifically for micro-pitch electronic packaging (such as MiniLED/MicroLED), requiring strict process demands such as ultra-fine pitch printing and high-reliability soldering. Its core features include:

• Ultra-fine Powder Size:
  • The powder particle size typically ranges from 1-15μm, with mainstream types including #6 powder (5-15μm), #7 powder (2-11μm), #8 powder (2-8μm), and #9 powder (1-5μm).
  • Some companies have achieved mass production of #T7-#T8 powder (2-8μm) to support higher-density packaging requirements.
• High-performance Flux System:
  • Optimized viscosity (approx. 50 Pa·s) and thixotropic index (4-7) ensure that the solder paste does not collapse after printing and maintains stable formation.
  • The stencil working time is greater than 10 hours, and the solder paste remains wet for over 10 hours after printing, offering a wide process window.

II. Key Industry Pain Points Addressed

Mini solder paste provides precise solutions for the four core problems in micro-pitch soldering:

• Solder Volume Accuracy: Supports ultra-fine printing with stencil apertures ≤40μm, effectively avoiding clogging or skipped printing during the printing process.
• Chip Placement: Through excellent rheological properties, it effectively reduces chip shifting, misalignment, and potential color difference issues during soldering.
• Thermal Shock Resistance: Some special alloys (such as SnSb10Ni0.5) can withstand secondary reflow soldering (peak temperature 265℃), significantly reducing the risk of desoldering.
• Solder Joint Quality: Good formation, full solder joints, strong thrust consistency, ensuring overall packaging reliability.

III. Main Application Scenarios

1. Mini LED / MicroLED Packaging

• Applicable to Flip-Chip structures, replacing silver paste can effectively reduce costs and thermal resistance, and improve thermal conductivity (up to 45W/M·K).
• Supports high-power LED packaging on ceramic substrates and other high-temperature carriers.

2. High-Density Electronic Assembly

• Used for mounting micro-components such as 01005 in SMT processes.
• Suitable for SiP (System-in-Package) and other high-precision soldering scenarios.

IV. Technical Evolution and Industry Trends

• Material Innovation: Water-soluble solder paste (e.g., DSP717HF) has gained industry recognition for its low-residue and high-reliability features. At the same time, environmentally friendly lead-free is a clear trend, with alloys such as SnSbNi gradually replacing traditional lead-containing formulations.
• Process Upgrade: By optimizing flux components such as thixotropic agents, the anti-slump performance of solder paste is enhanced to adapt to thinner stencils (e.g., 0.04mm). The synergistic optimization of solder paste materials with stencils and printing machines collectively pushes the soldering yield closer to the theoretical value of 99.99999%.