‌‌Solder Paste Failure Analysis & Solutions

1. Composition & Function‌

• ‌Solder Alloy Powder (85-90%)‌: Forms electrical connections (Sn-Pb, Sn-Ag-Cu, Sn-Bi).
• ‌Flux (10-15%)‌: Contains activators, thixotropic agents, resins, and solvents.

‌2. Common Failure Causes‌

• ‌Flux Overflow‌:
  • Excessive flux (>20%) or insufficient thixotropic agent.
  • Improper heating (rapid preheating causes solvent boiling).
• ‌Oxidation & Moisture‌: Degrades alloy powder and flux performance.

‌3. Analytical Methods‌

• ‌Metal Analysis (ICP-OES)‌: Measures Sn, Ag, Cu ratios.
• ‌Organic Analysis (GC-MS/Py-GCMS)‌: Identifies solvents and resins.

‌4. Improvement Solutions‌

• ‌Formula Adjustment‌: Reduce flux (<12%) or use high-boiling solvents.
• ‌Process Optimization‌: Extend preheating (60-120s) for better solvent evaporation.
• ‌Supplier Screening‌: Ensure thixotropic agent content meets standards.

‌Example‌: A smartphone manufacturer reduced flux overflow defects from 0.8% to 0.12% by adjusting flux content and preheating time, saving ¥2.3M annually.

(Note: For visual aids, include diagrams of solder paste composition, failure modes, and analytical techniques.)