Lead-Free Solder Pastes
The key variables in lead-free SMT are the higher reflow temperatures, flux activity, residue characteristics, cleanability, and pin testability. The slower wetting speeds associated with lead-free alloys require enhanced flux systems. Kester solder pastes have innovative flux systems that are specifically designed for lead-free assmebly. 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 Sn-Ag-Cu (tin-silver-copper).

Formula EnviroMark™ 907
No-Clean		 EnviroMark™ 909
No-Clean		 EnviroMark™ 808
Water-Soluble		 R520A
Water-Soluble
Kester
Part No.		 500g Jar 57-3043-9909 57-3043-9809 55-3443-0609 57-3843-8109
600g Cartridge 57-3043-9913 57-3043-9813 55-3443-0613 57-3843-8113
Application No-Clean Stencil Printing No-Clean Stencil Printing Water-Soluble Stencil Printing Water-Soluble Stencil Printing
Product Characteristics Designed to exceed customers' expectations for high yeild lead-free manufacturing. EM907 is engineered for the high thermal demands of assembling with lead-free alloys such as the family of SnAgCu (SAC). Joints are as cosmetically bright as SnPb joints. Prints down to 0201 pad sites. Designed to be reflowable in air as well as nitrogen. EM909 is a pin probeable solder paste specifically designed for the thermal requirements of lead-free alloys, including Sn96.5Ag3.0Cu0.5 alloy. The resulting solder joints closely resemble those of SnPb alloys. EM909 is also capable of stencil printing downtimes up to 90 minutes with an effective first print down to 20 mils without any kneading. Kester EM808 provides hours of stable stencil life, tack time and repeatable print definition. EM808's robust printing characteristics result in consistent solder paste volume regardless of idle time and print speed. The activator package is very aggressive and provides superior wetting to OSP coated and Immersion Silver boards. R502A is designed to solder effectively difficult metal surfaces in an air or nitrogen reflow atmosphere. The activator package is able to withstand the higher temperatures without slump. The flux system is non-hygroscopic, reducing paste waste at the printer. It is available in all common lead-free alloys.
Residue Characteristics Light Colored Soft, Light Colored Cleanable in Warm Water Cleanable in Warm Water
Copper Mirror Corrosion Low Low High High
Halide Tests Halide-Free Halide-Free Halide-Free Halide-Free
Surface Insulation Resistance Pass (Uncleaned) Pass (Uncleaned) Pass (Cleaned) Pass (Cleaned)
Printing Characteristics Excellent to 16 mils pitch (0.4 mm) Excellent to 16 mils pitch (0.4 mm) Excellent to 16 mils pitch (0.4 mm) Excellent to 16 mils pitch (0.4 mm)
Idle Time 60 Minutes at 70°-77°F
and 40-60% R.H.		 90 Minutes at 70°-77°F
and 40-60% R.H.		 60 Minutes at 70°-77°F
and 40-60% R.H.		 90 Minutes at 70°-77°F
and 40-60% R.H.
Maximum Print Speed Up to 150 mm/sec Up to 150 mm/sec Up to 150 mm/sec Up to 150 mm/sec
Typical Metal Percentage 88.5% Type III Powder
for Stencil Printing		 88% Type III Powder
for Stencil Printing		 88% Type III Powder
for Stencil Printing		 89.5% Type III Powder
for Stencil Printing
Expected Stencil Life 12+ Hours at 70°-77°F
and 40-60% R.H.		 12+ Hours at 70°-77°F
and 40-60% R.H.		 8+ Hours at 70°-77°F
and 40-60% R.H.		 8+ Hours at 70°-77°F
and 40-60% R.H.
Reflow Atmosphere Air or Nitrogen Air or Nitrogen Air or Nitrogen Air or Nitrogen
Compliant Specifications Telcordia Issue 1 GR-78-CORE
IPC/J-STD-004
Flux Designator ROLO		 Telcordia Issue 1 GR-78-CORE
IPC/J-STD-004
Flux Designator ROLO		 IPC/J-STD-004
Flux Designator ORMO		 IPC/J-STD-004
Flux Designator ORHO

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