Solder Composition
DSP718D- Sn/Ag/Cu (Tin/Silver/Cu) Alloys are designed as a lead-free alternative for Sn/Pb alloys for electronics
assembly operations (PCB assembly). The DSP718D Sn/Ag/Cu alloys conform and exceed the impurity requirements of J-Std-006
and all other relevant international standards.
Material Safety Data Sheets (MSDS)
XP718D Water Soluble Solder Paste MSDS
Typical Analysis
| |
Sn |
Ag |
Cu |
Pb |
Sb |
Bi |
In |
As |
Fe |
Ni |
Cd |
Al |
Zn |
Au |
| LF955-38 |
Bal |
3.6-4.0 |
0.5-0.9 |
0.050 Max |
0.050 Max |
0.050 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.005 Max |
0.001 Max |
0.001 Max |
0.001 Max |
0.002 Max |
| LF958-35 |
Bal |
3.3-3.7 |
0.5-0.9 |
0.050 Max |
0.050 Max |
0.050 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.005 Max |
0.001 Max |
0.001 Max |
0.001 Max |
0.002 Max |
| LF965-30 |
Bal |
2.8-3.2 |
0.3-0.7 |
0.050 Max |
0.050 Max |
0.050 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.005 Max |
0.001 Max |
0.001 Max |
0.001 Max |
0.002 Max |
| LF217 |
Bal |
3.8-4.2 |
0.3-0.7 |
0.050 Max |
0.050 Max |
0.050 Max |
0.050 Max |
0.010 Max |
0.010 Max |
0.005 Max |
0.001 Max |
0.001 Max |
0.001 Max |
0.002 Max | >
| |
Sn/Ag/Cu |
Sn63/Pb37 |
| Melting Point, °C |
217-221 |
183 E |
| Hardness, Brinell |
15HB |
14HB |
| Coefficient of Thermal Expansion |
Pure Sn=
23.5 |
24.7 |
| Tensile Strength, psi |
4312 |
4442 |
| Density, g/cc |
7.39 |
8.42 |
Electrical Resistivity,
(?ohm-cm) |
13.0 |
14.5 |
Electrical Conductivity,
%IACS |
16.6 |
11.9 |
| |
Sn/Ag/Cu |
Sn63/Pb37 |
| Yield Strength, psi |
3724 |
3950 |
| Total Elongation,% |
27 |
48 |
Joint Shear Strength,
at 0.1mm/min 20 °C |
27 |
23 |
Joint Shear Strength,
at 0.1mm/min 100 °C |
17 |
14 |
Creep Strength, N/mm2
at 0.1mm/min 20 °C |
13.0 |
3.3 |
Creep Strength, N/mm2
at 0.1mm/min 100 °C |
5 |
1 |
| Thermal Conductivity, W/m.K |
58.7 |
50.9 |
Particle Size
Sn/Ag/Cu alloys are available in Type 2 (75-45µm), 3(45-25µm), 4(38-20µm), and 5 (25-15µm) J-STD-005 powder
distribution. Solder powder distribution is measured utilizing laser diffraction, optical analysis and sieve analysis.
Careful control of solder powder manufacturing processes ensures the particles’ shape are 95% spherical
minimum (aspect ratio < 1.5) and that the alloy contains a typical maximum oxide level of 80 ppm.
Classification of Solder Powders by Particle Size
| Powder Type |
Fines |
Majority |
Coarse |
Typical Mesh |
| | <10% | >80% | >90% | <1% | 0% | |
| 1 | 20 | 75-150 | | 150 | 160 | 100/200 |
| 2 | 20 | 45-75 | | 75 | 80 | 200/325 |
| 3 | 20 | 25-45 | | 45 | 50 | 325/500 |
| 4 | 20 | | 20-38 | 38 | 40 | 400/635 |
| 5 | 15 | | 15-25 | 25 | 30 | 500 |
| 6 | 5 | | 5-15 | 15 | 20 | |
Metal Loading
Typical metal loading for dispensing application is 85-87 %. Compared to typical Sn63/Sn62 solder pastes
manufactured with 88% by weight metal loading, DSP718D Lead Free provides as much as 10-12% higher metal
volume than Sn63/Sn62. This increased in volume of DSP718D promotes better wetting and spreading of
Sn/Ag/Cu Lead Free alloy.
Solder Paste
Qualitek has developed a unique flux system designed specifically for high temperature lead free alloys. It
provides the fluxing activity levels that promote thermal stability and prevents thermal degradation when reflowing
under air atmosphere (normal). Since use of nitrogen is not required, 718D Lead Free Solder paste will provide
excellent cost savings.
In addition, 718D Lead Free solder paste exhibits superior joint strength, excellent wettability, extraordinary print
definition and tack life.
Main Features
- Low foaming
- Long tack time
- Excellent wettability
Dispensing
| |
Needle inner diameter |
Needle inner diameter |
Applicable powder |
| Needle Gauge |
in. |
µm |
(mesh cut) |
| 18 |
0.033 |
838 |
-200+325 |
| 20 |
0.023 |
584 |
-325+500 |
| 21 |
0.020 |
508 |
-325+500 |
| 22 |
0.016 |
406 |
-325+500 |
| 23 |
0.013 |
330 |
-325+500 |
| 25 |
0.010 |
254 |
-400+635 |
| 27 |
0.008 |
203 |
-500 |
The clearance gap between the needle and the substrate affects the shape and quality of the dot dispensed. If the
clearance is too little, the dot tends to be flattened out, and if too large, the dot tends to have long tailing.
Pressure
The pressure applied in the syringe should be kept at a minimum, and the proper head pressure kept in the range of 15-
25 lb/in2 (1.05-1.76 kg/cm2). In cases where a paste requires much higher pressure (more than 40 lb/in2 or 2.82 kg/
cm2) to dispense, the paste will become inconsistent and clogging may be expected. The external air pressure supply
should be maintained constant.
Open & Abandon Time
Tests have proven that DSP718D will perform during continuous dispensing for up to 8 hrs. The paste can be left in the
dispensing unit for up to 4 hours without paste drying out. If extended downtime is expected (>4 hrs) , the whole
dispensing system should be flushed without leaving any paste in any part of the system.
Paste Application
Solder paste should be taken out of the refrigerator at least 3 to 6 hours prior to use. This will give the paste enough
time to come to thermal equilibrium with the environment. The flow rate of paste in a dispensing application depends on
viscosity, which can be altered by temperature change. If solder paste is supplied in syringes pre-mixing is not
necessary due to the shear action produced from the dispensing.
APLICATION NOTES
Reflow
Best results have been acheived when DSP 718D is reflowed in a forced air convection oven with a minimum of 8
zones (top&bottom), however reflow is possible with a 4 zone oven (top & bottom).
The following is a recommended profile for a forced air convection reflow process. The melting temperature of the
solder, the heat resistance of the components, and the characteristics of the PCB (i.e. density, thickness, etc.)
determine the actual reflow profile.
Preheat Zone- The preheat zone, is also referred to as the ramp zone, and is used to elevate the temperature of the
PCB to the desired soak temperature. In the preheat zone the temperature of the PCB is constantly rising, at a rate that
should not exceed 2.5 C/sec. The oven’s preheat zone should normally occupy 25-33% of the total heated tunnel
length.
The Soak Zone- normally occupies 33-50% of the total heated tunnel length exposes the PCB to a relatively steady
temperature that will allow the components of different mass to be uniform in temperature. The soak zone also allows
the flux to concentrate and the volatiles to escape from the paste.
The Reflow Zone- or spike zone is to elevate the temperature of the PCB assembly from the activation temperature to
the recommended peak temperature. The activation temperature is always somewhat below the melting point of the
alloy, while the peak temperature is always above the melting point.
CLEANING
718D is water soluble formulation therefore the residues need to be removed. Residue removal is easily achieved, with
the use of hot 60 °C (140 °F) de-ionized water in either a batch or conveyorized cleaner. Spray pressures should be
maintained at 20-30 psi and conveyor speed of 3-6ft/min.
Storage & Shelf Life
It is recommended that solder paste be stored at a temperature of between 35-50 °F (2-10 °C) to minimize solvent
evaporation, flux separation, and chemical activity. If room temperature storage is necessary it should be maintain
between 68-77 °F (20-25 °C).
Shelf life
Unopened Container (35-50 °F/2-10°C) 6 months (from DOM)
Unopened Container (68-77 °F/20-25 °C)1 month (from DOM)
Opened Container (68-77 °F/20-25°C) 24 hours
Reusing Solder Paste
This is not normally recommended, because it typically generates more problems than it is worth. If you do decide to
reuse solder paste, these pointers may be helpful. This paste should be tightly sealed and refrigerated. Then, the
paste may be reused at a later date, provided that the paste has not separated or thickened significantly compared to its
original properties. Storage of syringes is preferred in an upright position with tip down to prevent flux separation and
air entrapment.
Working Environment
Solder paste performs best when used in a controlled environment. Maintaining ambient temperature of between 68-77
°F (20-25 °C) at a relative humidity of 40-65% will ensure consistent performance and maximum life of paste.
Cleaning Misprint Boards
If you should have a misprinted board, the paste may be cleaned off manually with alcohol (IPA) or Qualitek stencil
cleaner, SK-11. If you have a more elaborate board cleaner, the paste may be easily removed with use of a 5%
saponifier solution in hot DI water. Qualitek SK-44 saponifier could be used in this process.
Disposal
DSP 718D should be stored in a sealed container and disposed of in accordance with state & local authority
requirements.
Packaging
