Lead Free Solder Paste
Lead-Free Solder Paste The key variables in Lead-Free SMT are the higher reflow temperatures, flux activities, residue characteristics, cleanability, and pin testability. The slower wetting speeds associated with Lead-Free alloys require enhanced flux systems. Kester solder pastes have novel flux systems that are specifically designed for Lead-Free assembly. These new flux systems promote good wetting and excellent solder joint integrity at the higher temperatures commonly seen with most Lead-Free alloys such as SnAgCu.
No-Clean Lead-Free Solder Paste Formulas
| Formula | Application | Product Characteristics | Residue Removal Method | Atmosphere Required for Reflow | Compliant Specifications |
|---|---|---|---|---|---|
| R905 | Stencil Printing | Kester Lead-Free solder paste with a fine printing capability of 20 mils and a printing speed of 150mm/sec. Suitable for CSP and 0201 applications. Exhibits excellent compatibility with a wide variety of metallisation. The Exquisite paste flux system allows for a wide process printing window. | Not normally required but its residue can be easily removed using automated cleaning equipment (in-line or batch) with Kester #5252M Solvent Cleaner or #5260 Aqueous Cleaner. | Air or Nitrogen | Bellcore Issue 1 GR-78-Core IPC ANSI/J-STD-004 Flux Designator R0L0 |
| TCS-502-3 | Stencil Printing | A highly reliable paste with high insulation resistance flux residue. Exhibits great viscosity stability and excellent wettability. A robust paste that can be re-use even after printing. | Not normally required. | Air or Nitrogen | JIS-Z-3197 JIS-Z-3284 |
| TCS-531-1 | Stencil Printing | A newly developed Lead-Free paste that solves your CSP/BGA and fine pitch printing problems. TCS-531-1 uses fine solder powder and its flux system exhibits high reliability with high insulation and corrosion resistance. | Not normally required. | Air or Nitrogen | JIS-Z-3197 JIS-Z-3284 |
| TCS-552-1 | Stencil Printing | Designed for the fine pitch printing. Possesses good printing characteristics that do not promote bridging or smearing. The flux system is capable of controlling deactivation during pre-heating in order to achieve superior wettability and solder joints. A very stable paste suitable for long time printing. | Not normally required. | Air or Nitrogen | JIS-Z-3197 JIS-Z-3284 |
| R276 | Syringe Dispensing | Provides optimal performance in all types of dispensing applications. R276 is packaged void-free to ensure consistent dispensing in high speed automated processes. Exhibits excellent dispensing characteristics with a wide range of needle diameters. | Not normally required. | Air or Nitrogen | Bellcore Issue 1 GR-78-Core IPC ANSI/J-STD-004 Flux Designator R0L0 |
Water-Soluble Lead-Free Solder Paste Formulas
| Formula | Application | Product Characteristics | Residue Removal Method | Atmosphere Required for Reflow | Compliant Specifications |
|---|---|---|---|---|---|
| R520A | Stencil Printing | Designed to withstand higher temperatures that are needed when soldering with Lead-Free alloys. R520A exhibits minimal voiding, long stencil life and track time while still delivering exceptional solderability to a wide variety of metallic substrates. | Its residue can be easily removed using automated cleaning equipment (in-line or batch). Using de-ionised water at 49-60°C (120°F-140°F) or with 2% solution of Kester #5768 Bio-Kleen saponifier. | Air or Nitrogen | IPC ANSI/J-STD-004 Flux Designator 0RH0 |
| EnviroMark 522 | Stencil Printing | An organic acid formula specifically designed for the printing requirements of CSP, GBA and 0201 components. Its excellent paste release and print stability makes it ideal for challenging designs with ultra-fine pitches and small stencil openings. Offers good solderability and excellent wettability. | Its residue can be easily removed using automated cleaning equipment (in-line or batch). Use de-ionised water at 49°C-60°C (120°F-140°F). | Air or Nitrogen | IPC ANSI/J-STD-004 Flux Designator 0RH0 |
| R505 | Syringe Dispensing | Specially designed as a consistent dot dispensing paste for automated dispense equipment. The activator package in this formula is extremely aggressive; to remove tenacious oxide layers or to solder to OSP coated boards. Excellent dispensing characteristics with a capability to dispense 4 dots per second. | Its residue can be easily removed using automated cleaning equipment (in-line or batch). Use de-ionised water at 49°C-60°C (120°F-140°F) or with 2% solution of Kester #5768 Bio-Kleen saponifier. | Air or Nitrogen | IPC ANSI/J-STD-004 Flux Designator 0RH0 |