Anti-tombstoning No-clean Solder Paste

SSA48-M955

Feature

1) Ensures outstanding continual printability with fine pitch (0.5mm/20mil) and even super fine pitch (0.4mm/16mil) applications at slow to fast (20-100mm/sec.) print speed, combined with long stencil idle time.

2) Carefully selected thixotropic materials ensure excellent slump resistivity and significantly reduced occurrence of bridging and solder beading.

3) Specially developed flux system ensures both extremely high reliability and superior solder wetting.

4) Extremely long stencil and tack time offers a wide process window.

5) A small percentage of antimony (Sb) reduces the wetting tension forces and as a result, effectively drastically reduces tombstoning.

Specifications

Application Printing - Stencil

Product SSA48-M955

Composition (%) Sn62.6, Pb36.8, Ag0.4, Sb0.2

Shape Spherical

Melting point (°C) 183, 179 ? 190 All

oy

Particle size (µm) 20 - 45

Halide content (%) 0.0

Initial value ( ) > 1 × 1012Surface

insulation

resistance *1 After humidification ( ) > 1 × 1011

Aqueous solution resistivity*2 ( cm) > 5 × 104

Flu

x

Flux type ROL0

Flux content (%) 10

Viscosity*3 (Pa.S) 200

Copper plate corrosion*4 Passed

Solder spread factor (%) 90

Tack time > 36 hours

Pro

duct

Shelf life (below 10°C) 6 months

1. SIR ....................... .....................................40 90%RH 96Hr 2. Aqueous solution resistivity.................... ... In accordance with MIL specifications. 3. Viscosity.................................................... Malcom spiral type viscometer, PCU-2 at 25 10rpm 4. Copper plate corrosion ............................... In accordance with JIS.

Printability Wettiing(Continual printing at 50mm/sec., w/out cleaning)

Self-alignment

To see the strength of wetting tension, which could cause tombstoning, the components, were mounted at angles of 0°,

10°, 20°, 30°, and 40°.

Result : SSA48-M955 indicates less wetting tension than Sn63Pb37 solder paste.

Tackiness Recommended reflow profile

1608 resistor

0

50

100

150

200

0 5 10 15 20 25 30 35

Time (hour)

Ta

ckin

ess

(g

f)

Tester : Malcom FG-1

Temperature : 23 2°C

Probe speed : 10mm/sec.

Probe load : 50gf

Probe loading time : 0.2sec.

SSA48-M955

Conventional paste

Mount angle

10°

0°

20°

30°

40°

SSA48-M955(Sn62.6Pb36.8Ag0.4Sb0.2)

Before reflow After reflow

SE48-M955(Sn63Pb37)

32-1, Senju Asahi-cho, Adachi-ku, Tokyo 120-0026

Tel : (03) 5244-1521 Fax : (03) 5244-1527 www.ko-ki.co.jp

Peak temp. 210~225°C 5sec.

Over 200°C 30~40sec.

50

100

150

200

250

Ramp-up temp. 1.5~3.0°C /sec.

12060 180 240 300

(sec.)

Pre-heat temp. 140~170°C 60~120sec.

(°C)

0.4mm pitch (30th print) NiFe QFP lead(SnPb plating)